From theremin1 at worldnet.att.net  Fri Jan  1 10:50:17 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Fri, 1 Jan 1999 01:50:17 -0800
Subject: DJ
Message-ID: <001301be356c$242817e0$db744e0c@hpcustomer>


-----Original Message-----
From: Claire F. <wils0450 at itlabs.umn.edu>
To: Synth-DIY <synth-diy at mailhost.bpa.nl>
Date: Thursday, December 31, 1998 1:55 PM


> Pleasent thought for the day: Electronics aren't quite as tough as I
>thought they would be. Kinda'like being a DJ...sort of.

Seems you need to find more ambitious projects, then!  (;
Happy New Year to everyone.

-Art 





From james at newd.demon.co.uk  Fri Jan  1 17:28:20 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Fri, 01 Jan 1999 16:28:20 +0000
Subject: ASM-1
Message-ID: <1.5.4.32.19990101162820.0067c27c@pop3.demon.co.uk>

Has anybody made the above synth (ASM-1)? Is it good, easy to use etc.etc.

Thanks,
James.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk
-------------------------------------------------------------------------------




From magnus at analogue.org  Fri Jan  1 19:40:00 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 01 Jan 1999 19:40:00 +0100
Subject: ASM-1
In-Reply-To: Your message of "Fri, 01 Jan 1999 16:28:20 +0000"
References: <1.5.4.32.19990101162820.0067c27c@pop3.demon.co.uk>
Message-ID: <199901011840.TAA07114@mail2.it.kth.se>

>>>>> "JJ" == James Jackson <james at newd.demon.co.uk> writes:

Hi James!

 JJ> Has anybody made the above synth (ASM-1)? Is it good, easy to use etc.etc.

At the end of the ASM-1 homepage
(http://www.it.kth.se/~e93_mda/synths/friends/stopp/)
you can find a number of ASM-1 pages from people who built it (well,
the ASM-1 homepage is such a page in itself). Also, there are a bunch
of people here that does not have webpage (what!?) of their ASM-1, but
are more than competent to answer this question among others.

For my own part I can say that it is a fairly easy project to build.
Depending on how you design your frontpanel your flexibility may vary.

Cheers,
Magnus



From cyborg0 at GlobalEyes.net  Fri Jan  1 23:16:27 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 01 Jan 1999 16:16:27 -0600
Subject: MIDI port, uPD, and FPGA
References: <981231122753.53000bef@tnclus.ntc.nokia.com>
Message-ID: <368D493B.4C32570@globaleyes.net>

Mikko Helin wrote:


> An alternative and a better solution is a microcontroller
> like PIC16F84 with a DAC.
> 
I see someone other than myself has tried to get a complete discrete
logic midi2cv unit working! :))
That was one of my first projects.. I basically ended up building a
giant discrete specialized computer, but man did I learn a LOT!

I would say that if you can do it with a PIC, go for it..much easier..
I had blisters on my fingers from pulling wires in and out of the
breadboard when I was troubleshooting my hardware based midi2cv!

Or, you *might* be able to use an FPGA, that is, if you really want to
do it without having to program in assembler or C.. They have schematic
capture on some FPGA software, very cool.

Oh, BTW, anyone ever do any FPGA work? I am SUPER interested in
learning, but it seems such a morass of useless info when I try to find
details about it..
Rob



From magnus at analogue.org  Sat Jan  2 00:14:03 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 02 Jan 1999 00:14:03 +0100
Subject: Env vco!
In-Reply-To: Your message of "Fri, 01 Jan 1999 21:48:16 -0800"
References: <368DB320.63EC@swipnet.se>
Message-ID: <199901012314.AAA08263@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> Many years ago needed a VCO with a saw wave,and i
 B> found a way to do this using a 4046 PLL.

BJ, you forgot to put a value on R11. I suggest a 100k.

Also, why don't you let the cursuit take more of all that space?
I try to scale up my schematics when they don't take that much space.

 B> And the MC202 and SH101 envelopgenerator and a simple VCO are found at:
 B> http://home8.swipnet.se/~w-88660/schpcb.htm

For those that wishes to use an exponential cursuit with the 4046 VCO
may hook it in on the current input of pin 12. This input wishes to
see a current being drawn towards ground, so hooking it to the current
output of a standard dual-transistor expo-cursuit (like the ASM-1 for
instance) should go well.

Also, you may still use the VCO input for a real linear input (pin 9).

The 4046 VCO have a typical linearity of about +/- 1 % and a
temperature stability of +/- 0.12% (+/- 1200 ppm) at 5V. The linearity
depends on the resistor to ground from pin 11, it should be at least
10k, put 100k is recommended (for 0.5% linearity). The temperature
dependency drops to +/- 150 ppm when the powersuppy is at 15V.

You could make som strange form of modulation by dribbling with the
inhibit line, and thus pausing the load cycle (it shuts of the
current-mirror). It is not synching, it is just diffrent.

The old CMOS versions of this VCO would scream up to 0.8-2.4 MHz
(depending on powersupply), the newer onces get even higher. So, to
get a pretty good responce one should consider pretty quick op-amps.
The reset time is quite small, but if one would find it a trouble,
then you could allways add the Franco compensation resistor in series
with capacitor.

The upside about using the 4046 as a core for a VCO is that you get
the reset-cursuit for free as well as phase detectors to make PLL
loops, in case you would fancy that game. BJ reused one of those to
make a MS-20 style ringmod.

Oh, be carefull about loading the capacitor, use high-impedance
op-amps (about 1 Tohm). Also, it could be a good idea to feed back the
outputs of the op-amps to form guard rings around the capacitor
terminals. This would eat surface currents, usefull if you want it to
track good at low current (frequency).

 B> Regards
 B> Grommit.

Cheers,
Wallace



From magnus at analogue.org  Sat Jan  2 02:44:22 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 02 Jan 1999 02:44:22 +0100
Subject: Env vco!
In-Reply-To: Your message of "Sat, 02 Jan 1999 02:01:10 -0800"
References: <368DEE66.72FB@swipnet.se>
Message-ID: <199901020144.CAA09083@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

Hi there!

 >> BJ, you forgot to put a value on R11. I suggest a 100k.

 B> Sorry i forgot, the value depends on the range you want to use.
 B> 100k is fine. 

Right, but as things happends 100k is also a very good value for the
linearity. The linearity problem is partly due to the input FET, so
you may acheive better result by hooking in directly to the current
input, then you are pulling current directly from the current-mirror.
The linearity that the 4046 has is acceptable for most of the PLL
applications that it is intended for.
 
 >> Also, why don't you let the cursuit take more of all that space?
 >> I try to scale up my schematics when they don't take that much space.

 B> Because im lacy. :)

OK, I'll by that ;)

In my Postscript schematics I have a scale factor, so it is a small
thing fixing it compared to all the work getting the schematic in.
But then, my way of doing schematics is a bit braindamaging in the
first place, so I better have some freedome as a benefit ;)

 >> 
 B> And the MC202 and SH101 envelopgenerator and a simple VCO are found at:
 B> http://home8.swipnet.se/~w-88660/schpcb.htm
 >> 
 >> For those that wishes to use an exponential cursuit with the 4046 VCO
 >> may hook it in on the current input of pin 12. This input wishes to
 >> see a current being drawn towards ground, so hooking it to the current
 >> output of a standard dual-transistor expo-cursuit (like the ASM-1 for
 >> instance) should go well.

 B> Yes you may do so, i have , but the linearity is no good, One may use
 B> the HC7046 who has even better linearity, i think it was approx 0.15%.

Hmm... was there a need for high-end compensation maybe?
 
 >> Also, you may still use the VCO input for a real linear input (pin 9).

 B> Yes again, this is good, i dont have to explain my own designs 
 B> Magnus does it wery well indeed, great i can keep doing my 
 B> lacy ,sleepy things here! :)

Well, since you didn't someone had to ;^)

 >> The old CMOS versions of this VCO would scream up to 0.8-2.4 MHz
 >> (depending on powersupply), the newer onces get even higher. So, to
 >> get a pretty good responce one should consider pretty quick op-amps.
 >> The reset time is quite small, but if one would find it a trouble,
 >> then you could allways add the Franco compensation resistor in series
 >> with capacitor.
 
 >> The upside about using the 4046 as a core for a VCO is that you get
 >> the reset-cursuit for free as well as phase detectors to make PLL
 >> loops, in case you would fancy that game. BJ reused one of those to
 >> make a MS-20 style ringmod.

 B> Yes again, wery nice thanks for the "going thru" my designs, ooh i think 
 B> i have a cup of teee, and a smorgas while you other listening to Magnus
 B> .:) 

Funny, I was just about to get a cup of tea and a smorg?s too...
 
 >> Oh, be carefull about loading the capacitor, use high-impedance
 >> op-amps (about 1 Tohm). 

 B> Yes that right, or one may use FET's as buffers.
 B> The frequency will shift down a bit if the cap is loaded to much.
 B> When i did this design, it was for a pecussion synt voice,
 B> I was just measuring around, and foundout about the charging
 B> phases for the VCO and saw then the possibility to have a SAW wave.

Also, a little warning: When the 4046 flips, it will earth the
capacitor end that is positive, thus making the negative end going
below 0V (to -2.5 V in BJ's 5V design), so either is op-amps on a
differential supply (which the -5V feed to the summing op-amp needs
anyway) or (when you have the op-amp in +5V/0V single feed) you must
have op-amps that does not go crazy for the input to go below the
negativ rail.

 B> Pitty that the EN pin dont reset the charging phase of the cap!

Certainly, but if you add a CMOS (4066 or something) switch over the
cap, you may get a reset anyway. Another method would be a pair of
FETs on each side reseting to earth.

 B> Regards
 B> Haddock!

Cheers,
Tintin



From jdm at synthcom.com  Sat Jan  2 03:30:49 1999
From: jdm at synthcom.com (J.D.McEachin)
Date: Fri, 01 Jan 1999 18:30:49 -0800
Subject: ASM-1 on Album, Cover
Message-ID: <3.0.5.32.19990101183049.00ae2210@synthcom.com>

I guess it was inevitable.  The band "Dweller At The Threshold" has used
several ASM-1's on their new album, and even pictured them on the CD cover.
 There's a picture at:  http://www.eurock.com/features/dat/index.html , but
it's difficult to make out (it helps if you know what Chris List's panels
look like.

If you like Tangerine Dream inspired electronic music, then you'll probably
like their music.  Be sure to check out the realaudio clip.

JDM

PS I should probably warn you - I'm a friend of DAT member Dave Fulton, who
sometimes posts to this list...





From magnus at analogue.org  Sat Jan  2 04:57:46 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 02 Jan 1999 04:57:46 +0100
Subject: ASM-1 on Album, Cover
In-Reply-To: Your message of "Fri, 01 Jan 1999 18:30:49 -0800"
References: <3.0.5.32.19990101183049.00ae2210@synthcom.com>
Message-ID: <199901020357.EAA09434@mail2.it.kth.se>

>>>>> "JDM" == J D McEachin <jdm at synthcom.com> writes:

 JDM> I guess it was inevitable.  The band "Dweller At The Threshold" has used
 JDM> several ASM-1's on their new album, and even pictured them on the CD cover.
 JDM>  There's a picture at:  http://www.eurock.com/features/dat/index.html , but
 JDM> it's difficult to make out (it helps if you know what Chris List's panels
 JDM> look like.

Well, I added a link to them from the ASM-1 homepage, it seemed so appropriate!

 JDM> If you like Tangerine Dream inspired electronic music, then you'll probably
 JDM> like their music.  Be sure to check out the realaudio clip.

Well, I do.

 JDM> JDM

 JDM> PS I should probably warn you - I'm a friend of DAT member Dave Fulton, who
 JDM> sometimes posts to this list...

Good, now we know who to blame!

Could Dave maybe give any specifics?

Thanks for sharing this!

Cheers,
Magnus




From zzynt at swipnet.se  Sat Jan  2 06:48:16 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 01 Jan 1999 21:48:16 -0800
Subject: Env vco!
References: <yam7669.130.119872296@mail.mindspring.com>
Message-ID: <368DB320.63EC@swipnet.se>

Many years ago needed a VCO with a saw wave,and i
found a way to do this using a 4046 PLL.

And the MC202 and SH101 envelopgenerator and a simple VCO are found at:
http://home8.swipnet.se/~w-88660/schpcb.htm

Regards
Grommit.



From zzynt at swipnet.se  Sat Jan  2 07:00:25 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 01 Jan 1999 22:00:25 -0800
Subject: He
References: <001a01be348d$4718e700$1b7a4e0c@hpcustomer>
Message-ID: <368DB5F9.33BA@swipnet.se>

He



From zzynt at swipnet.se  Sat Jan  2 07:00:48 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 01 Jan 1999 22:00:48 -0800
Subject: ll
References: <yam7669.130.119872296@mail.mindspring.com>
Message-ID: <368DB610.1BA3@swipnet.se>

ll



From zzynt at swipnet.se  Sat Jan  2 07:01:22 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 01 Jan 1999 22:01:22 -0800
Subject: oo
References: <yam7669.130.119872296@mail.mindspring.com>
Message-ID: <368DB632.6F1F@swipnet.se>

oo!

:)
BJ



From don at till.com  Sat Jan  2 09:24:25 1999
From: don at till.com (Don Tillman)
Date: Sat, 2 Jan 1999 00:24:25 -0800 (PST)
Subject: Don's interpolating scanner
Message-ID: <199901020824.AAA16475@shell9.ba.best.com>

Happy New Year all!

I've *finally* finished the article I was writing about my
interpolating scanner design.  Enjoy...

http://www.till.com/articles/scanner/index.html

(It was heavily inspired by Juergen's work and benefits from
at least a couple of his suggestions.)

The basic idea is to build an N-way diff amp circuit to drive the
current-controlled amps, taking advantage of the symmetrical
exponential transfer characteristic for a smoother transition between
the inputs.  It also has a pretty low parts count.

  -- Don




From zzynt at swipnet.se  Sat Jan  2 11:01:10 1999
From: zzynt at swipnet.se (BJ)
Date: Sat, 02 Jan 1999 02:01:10 -0800
Subject: Env vco!
References: <368DB320.63EC@swipnet.se> <199901012314.AAA08263@mail2.it.kth.se>
Message-ID: <368DEE66.72FB@swipnet.se>

Magnus Danielson wrote:
> 
> >>>>> "B" == BJ  <zzynt at swipnet.se> writes:
> 
>  B> Many years ago needed a VCO with a saw wave,and i
>  B> found a way to do this using a 4046 PLL.
> 
> BJ, you forgot to put a value on R11. I suggest a 100k.

Sorry i forgot, the value depends on the range you want to use.
100k is fine. 
 
> Also, why don't you let the cursuit take more of all that space?
> I try to scale up my schematics when they don't take that much space.

Because im lacy. :)

> 
>  B> And the MC202 and SH101 envelopgenerator and a simple VCO are found at:
>  B> http://home8.swipnet.se/~w-88660/schpcb.htm
> 
> For those that wishes to use an exponential cursuit with the 4046 VCO
> may hook it in on the current input of pin 12. This input wishes to
> see a current being drawn towards ground, so hooking it to the current
> output of a standard dual-transistor expo-cursuit (like the ASM-1 for
> instance) should go well.

Yes you may do so, i have , but the linearity is no good, One may use
the HC7046 who has even better linearity, i think it was approx 0.15%.
 
> Also, you may still use the VCO input for a real linear input (pin 9).

Yes again, this is good, i dont have to explain my own designs 
Magnus does it wery well indeed, great i can keep doing my 
lacy ,sleepy things here! :)

> The old CMOS versions of this VCO would scream up to 0.8-2.4 MHz
> (depending on powersupply), the newer onces get even higher. So, to
> get a pretty good responce one should consider pretty quick op-amps.
> The reset time is quite small, but if one would find it a trouble,
> then you could allways add the Franco compensation resistor in series
> with capacitor.
 
> The upside about using the 4046 as a core for a VCO is that you get
> the reset-cursuit for free as well as phase detectors to make PLL
> loops, in case you would fancy that game. BJ reused one of those to
> make a MS-20 style ringmod.

Yes again, wery nice thanks for the "going thru" my designs, ooh i think 
i have a cup of teee, and a smorgas while you other listening to Magnus
.:) 
 
> Oh, be carefull about loading the capacitor, use high-impedance
> op-amps (about 1 Tohm). 

Yes that right, or one may use FET's as buffers.
The frequency will shift down a bit if the cap is loaded to much.
When i did this design, it was for a pecussion synt voice,
I was just measuring around, and foundout about the charging
phases for the VCO and saw then the possibility to have a SAW wave.

Pitty that the EN pin dont reset the charging phase of the cap!

Regards
Haddock!



From zzynt at swipnet.se  Sat Jan  2 11:18:20 1999
From: zzynt at swipnet.se (BJ)
Date: Sat, 02 Jan 1999 02:18:20 -0800
Subject: Env vco!
References: <368DB320.63EC@swipnet.se> <199901012314.AAA08263@mail2.it.kth.se>
Message-ID: <368DF26C.4A8A@swipnet.se>

Magnus Danielson wrote:
> 
> >>>>> "B" == BJ  <zzynt at swipnet.se> writes:
> 
>  B> Many years ago needed a VCO with a saw wave,and i
>  B> found a way to do this using a 4046 PLL.
> 
> BJ, you forgot to put a value on R11. I suggest a 100k.

Oh, now i remember, it was for the user to decide! :)

> Also, why don't you let the cursuit take more of all that space?
> I try to scale up my schematics when they don't take that much space.

I am a minimalist, therfore i build with SMD!!  horror!!!
Oahahah ,you "cursuit" person you. You missed the "i", one nill to meee
!

BJ :)



From vco at mindspring.com  Sat Jan  2 11:40:14 1999
From: vco at mindspring.com (tomg)
Date: Sat, 02 Jan 1999 05:40:14 -0500
Subject: VCO-1C
Message-ID: <yam7671.713.119020696@mail.mindspring.com>


Super simple 4 tranny unijunction VCO. May be the worlds
smallest descret 1V/OCT VCO. Works a lot better than it looks.

http://www.mindspring.com/~vco/misc/pics/vco1c_sd.gif

-tg




From varner at k-online.com  Sat Jan  2 19:10:25 1999
From: varner at k-online.com (Steve Varner)
Date: Sat, 02 Jan 1999 10:10:25 -0800
Subject: CA3046 exponential converter
Message-ID: <368E610E.13C89E69@k-online.com>

Barry Klein has a CA3046 exponential converter (fig.4-4, p.87) in his
"Electronic music circuits." This is the same as the ENS-76 VCO option
1A found in the "Preferred Circuits Collection." These schematics show
temperature compensation using the 2k tempco.
Barry also has a CA3046 2-transistor thermostat circuit (Fig. 4-3, p.86)
using the remaining transistors on the array (Q4 and Q5). It seems very
simple. (I suppose you would then leave off the tempco resistor and
replace it with a regular resistor.)
Has anyone built this exact VCO setup? If it works well... godbye
matched pairs and tempcos for me. 3046's only cost about 35 cents.

(And yes, I have seen the AN-299 VCO circuit. Anyone actually built one
of these into a VCO module?)

Steve Varner
mailto:varner at k-online.com




From synth1 at airmail.net  Sat Jan  2 20:10:18 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sat, 2 Jan 1999 13:10:18 -0600
Subject: CA3046 exponential converter
Message-ID: <000801be3683$9b968060$841588cf@paults>

I'm restoring a Moog 15 modular, and the 921 VCO uses 3046 arrays as the
expo gen.
It also uses 1K tempcos UNDER the chip (as opposed to on the top). The chip
is
in a socket, which is just tall enough to allow the 3046 to sit on top. I
did this in the MG-1
as well.

In fact, the MG-1 VCO is pretty much the same as the Moog modular. The main
difference
is the modular uses a CA3080 as the comparator (!!?!) to switch the PNP
across the integration
cap. Else, it's full of hand-selected 741s (BARF!!). No wonder they drift
like mad!! I suggest looking
at the OP-07 "family" of op amps for input summers (OP-07, OP-27, etc).
Input bias current is
not the issue, it's offset voltage and current drift. The Linear Tech LT1013
is also a good part.

As an aside, the circuitry in the Moog modular is sort of like looking under
the hood of a Model T.
Most of the pc boards don't even have solder masks or silkscreens. This
particular one was built
in 1977, and most of the electrolytic caps are starting to split apart. The
measured signal-to-noise
ratio (like on the filter and VCA) is around 58dB, which is like FM radio
(not to brag, but the SNR of
the MOTM VCA is 82 dB).

Paul Schreiber
Synthesis Technology
www.synthtech.com





From wils0450 at itlabs.umn.edu  Sat Jan  2 20:37:04 1999
From: wils0450 at itlabs.umn.edu (Claire F.)
Date: Sat, 2 Jan 1999 13:37:04 -0600 (CST)
Subject: archives
Message-ID: <Pine.GSO.4.05.9901021328150.17103-100000@beluga.itlabs.umn.edu>

Hello all. We had a synthesis group meeting this week and talked a lot
about what we wanted to do with the web page. One of the big concerns was
to make it as friendly as possible for the begining hobbiest. The only
problem  is, we are all beginners and haven't built a whole lot of
projects. 
What I was hoping was that we could "mirror" a lot of the projects that
you guys have designed and made available on your pages with a link to
your page from each project that you would allow us to have on the site. 
If this doesn't sound like something you would want to do, I beg you to at
least send me a short desc. of a poece or two from page with an
appropriate level of difficulty. A one-to-ten scale would be easiest for a
lot of people to understand (I think), because of the movies and all.
Looking forward to any contribution anyone wants to make, as well as the
usual criticisims, etc...

Kind of a community action one-stop DIY spot.   :)

                 "There always lies so near to us a realm
        in which we have escaped entirely from all our affliction..."






From edusilva at bahianet.com.br  Sat Jan  2 21:31:56 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 2 Jan 1999 18:31:56 -0200
Subject: Headphone amps 
Message-ID: <199901022037.SAA13266@postman.bahianet.com.br>

Peter Cornell <peterc at pop.onwe.co.za> wrote:

> Hi list
> 
> There was a query about headphone amps valve or otherwise recently.
> 
> Check out
> headwize.com
> for a few interesting circuits
> 
> Peter Cornell

The more I learn, the less I know...  ;)


_____________________
Edu Silva - ES2 Audio
Salvador-Bahia-Brasil



From edusilva at bahianet.com.br  Sat Jan  2 23:46:00 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 2 Jan 1999 20:46:00 -0200
Subject: Line Levels
Message-ID: <199901022340.VAA25791@postman.bahianet.com.br>

James Jackson <james at newd.demon.co.uk> wrote:
 
> Also, does anybody know of any phone pre-amp circuits?

Do you mean "phono"?
 
http://www.rane.com/ps1.htm
http://nyquist.ee.ualberta.ca/~charro/cookbook/audio/riaa.doc
http://www.infomaniak.ch/~bonavolt/audioel.htm#RIAA Preamps

> Thanks,
> James.

Ask again if you need more.

_____________________
Edu Silva - ES2 Audio
Salvador-Bahia-Brasil



From jhaible at primus-online.de  Sun Jan  3 00:14:40 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 3 Jan 1999 00:14:40 +0100
Subject: AW: Don's interpolating scanner
Message-ID: <19990102231747.6493.qmail@nuernberg2.pop.metronet.de>


> I've *finally* finished the article I was writing about my
> interpolating scanner design.  Enjoy...
> 
> http://www.till.com/articles/scanner/index.html
> 
> (It was heavily inspired by Juergen's work and benefits from
> at least a couple of his suggestions.)
> 
> The basic idea is to build an N-way diff amp circuit to drive the
> current-controlled amps, taking advantage of the symmetrical
> exponential transfer characteristic for a smoother transition between
> the inputs.  It also has a pretty low parts count.
> 
>   -- Don

Congrats to Don for further improoving the Scanner idea !
Now I hope you will soon come up with a ready circuit for the full
Hammond Chorus emulation ! (for the list: Don gave me valuable
hints to simplify a general gyrator circuit for this application, but
I never came to really try it.)

I really like the idea of a smooth, and even variable transition. 
Should have a real advantage in waveform generation.
You wrote about transistor matching. Did you simulate temperature
effects as well ? (If there is a temperature effect on the waveform,
one might compensate it with the shape control voltage ...)

I may have mentioned this before, but I also have worked out a
simplified all-transistor / smooth transition version of the Scanner.
There is not much description, but the schematics can be found
in the JH-4 section of my homepage (The filter scanner of the
JH-4 VCA). 
I use two cascaded transistors
for each channel, one driven from the base, and one driven from
the emitter. The design goals were different from Don's, however.
While I also wanted a simplified version, I needed different width
of the separate triangle windows. I can set both end points and both
ramps of each window separately, and I can even have a trapezoid
shape. The big downside is that it's all set by a handful of resistors
that are very different to calculate. (I only got the desired courves
with spice simulation parameter sweeps.) 

Don's circuit is very elegant - can't await the full Hammond Vibrato 
version !

JH.



From theremin1 at worldnet.att.net  Sun Jan  3 01:54:49 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Sat, 2 Jan 1999 16:54:49 -0800
Subject: archives
Message-ID: <001401be36b3$aaef2dc0$dc774e0c@hpcustomer>

Claire,

Please feel free to provide links to any articles or features on my 
theremin page.  Specifically, the article for a ten-transistor therry, at: 
http://home.att.net/~theremin1/SWTP.htm is a nice mid-level project.

Naturally, I would be happy to provide a reciprocal link, once you're
"up and running."  The folks at http://www.adsr.com/ might also like to 
provide a link to your "One Stop" page, from their page.  

I realize that there are fundamental differences in keyboard synthesis 
culture and theremin culture, but the theremin is, nonetheless, a viable 
and fascinating electronic musical instrument.

-Art Harrison

-----Original Message-----
From: Claire F. <wils0450 at itlabs.umn.edu>
To: Synth-DIY <synth-diy at mailhost.bpa.nl>
Date: Saturday, January 02, 1999 1:02 PM
Subject: archives


>Hello all. We had a synthesis group meeting this week and talked a lot
>about what we wanted to do with the web page. One of the big concerns was
>to make it as friendly as possible for the begining hobbiest. The only
>problem  is, we are all beginners and haven't built a whole lot of
>projects. 
>What I was hoping was that we could "mirror" a lot of the projects that
>you guys have designed and made available on your pages with a link to
>your page from each project that you would allow us to have on the site. 
>If this doesn't sound like something you would want to do, I beg you to at
>least send me a short desc. of a poece or two from page with an
>appropriate level of difficulty. A one-to-ten scale would be easiest for a
>lot of people to understand (I think), because of the movies and all.
>Looking forward to any contribution anyone wants to make, as well as the
>usual criticisims, etc...
>
>Kind of a community action one-stop DIY spot.   :)
>
>                 "There always lies so near to us a realm
>        in which we have escaped entirely from all our affliction..."
>
>
>




From magnus at analogue.org  Sun Jan  3 03:48:14 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 03 Jan 1999 03:48:14 +0100
Subject: archives
In-Reply-To: Your message of "Sat, 2 Jan 1999 13:37:04 -0600 (CST)"
References: <Pine.GSO.4.05.9901021328150.17103-100000@beluga.itlabs.umn.edu>
Message-ID: <199901030248.DAA22458@mail2.it.kth.se>

>>>>> "CF" == Claire F <wils0450 at itlabs.umn.edu> writes:

 CF> Hello all.

Hej!

 CF> We had a synthesis group meeting this week and talked a lot
 CF> about what we wanted to do with the web page. One of the big concerns was
 CF> to make it as friendly as possible for the begining hobbiest. The only
 CF> problem  is, we are all beginners and haven't built a whole lot of
 CF> projects. 

Just get going, once you see it you figure out what went wrong and
what went right. If you look at many of the pages out there, they have
too evolved over a long time. The key however, is to from the start
think big and allow for future expansion over years to come, without
breaking the old material. Think URL conservatively, that is, once you
put some page up, let that URL be there, since people will link it
from all over the place, thus trowing that page will trow a lots of
links to you, which is a bad thing. This requires that one try to put
some vauge basic structure up first, but which allows for expansion
later. The exact design is a moving target issue. Also, throw most of
the flying gizmo's stuff, it just anoys people, takes longer time to
download and rarely add any value to the content. Frames, JavaScripts,
jingles etc. are among the things I am talking about. Structure and
content beats all that, few people understood the need for both.

 CF> What I was hoping was that we could "mirror" a lot of the projects that
 CF> you guys have designed and made available on your pages with a link to
 CF> your page from each project that you would allow us to have on the site. 

Link all you like.

 CF> If this doesn't sound like something you would want to do, I beg you to at
 CF> least send me a short desc. of a poece or two from page with an
 CF> appropriate level of difficulty. A one-to-ten scale would be easiest for a
 CF> lot of people to understand (I think), because of the movies and all.

This varies in the world, a 5-grade scale is not uncommon, also in US
you see a lot of 5 and 6 grade scales. Then there is these that go very
hard on things and only see things in a 2-grade scale (good/bad, white/black).

I would settle for a 5-grade scale, it would give enought hints, also
consider that everyone does not have the same reference of what is
easy and what is difficult. What I may consider fairly simple may be
an astonashing mountain of diffictulties for others. How, would they
then consider the things I consider hard? They would settle for no
less than a full-blown rocket science project. Try to get some scale
up where we may compare things, then we have something common to
releate to. Also, there is allways diffrent difficulties, so one
should know what they are. Judgement without colourary comments are
hard to understand.

Dont forget traceability of information, in many cases one see that
information just pops up, and you don't know how to trace it to the
source either to learn more or to find an error.

 CF> Looking forward to any contribution anyone wants to make, as well as the
 CF> usual criticisims, etc...

 CF> Kind of a community action one-stop DIY spot.   :)

Ah, well...

PS. Check out my page at http://www.it.kth.se/~e93_mda/

Cheers,
Magnus



From magnus at analogue.org  Sun Jan  3 04:21:57 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 03 Jan 1999 04:21:57 +0100
Subject: AW: Don's interpolating scanner
In-Reply-To: Your message of "Sun, 3 Jan 1999 00:14:40 +0100"
References: <19990102231747.6493.qmail@nuernberg2.pop.metronet.de>
Message-ID: <199901030321.EAA22556@mail2.it.kth.se>

>>>>> "j" == jhaible  <jhaible at primus-online.de> writes:

 >> I've *finally* finished the article I was writing about my
 >> interpolating scanner design.  Enjoy...
 >> 
 >> http://www.till.com/articles/scanner/index.html
 >> 
 >> (It was heavily inspired by Juergen's work and benefits from
 >> at least a couple of his suggestions.)
 >> 
 >> The basic idea is to build an N-way diff amp circuit to drive the
 >> current-controlled amps, taking advantage of the symmetrical
 >> exponential transfer characteristic for a smoother transition between
 >> the inputs.  It also has a pretty low parts count.
 >> 
 >> -- Don

 j> Congrats to Don for further improoving the Scanner idea !
 j> Now I hope you will soon come up with a ready circuit for the full
 j> Hammond Chorus emulation ! (for the list: Don gave me valuable
 j> hints to simplify a general gyrator circuit for this application, but
 j> I never came to really try it.)

I agree, certainly an interesting piece of work!

Now, this rings a bell. I have also been pondering over the Hammond
A-100 schematics and the scanner chorus.

I have a little diffrent solution that does not require as many
VCAs. In it's basic layout it only requires 2 VCAs. Let's consider a
8-input scanner.

First I would have two 8-to-1 analog muxes (4051's) to select two
adjacent inputs, each being feed into the 2 VCAs. The VCAs are being
feed with linear CVs being directly invertion of the other (other
relations may be selected, I take this for simplification). When one
of the VCAs is in the bottom end, that VCAs channel is switched to the
other adjacent channel (say, if we just faded from 1 to 2, the
outfaded ch. 1 will now be replaced with a outfaded ch. 3). The
outputs of these VCAs is summed just as you would expect. You would
need to care some for the exact handling of scanner CV input to VCA
control as well as the machinery that selects channels. This becomes
apparent if you consider that a CV may change direction (the channel
selection must not be upset) or that you make a infinitely
increasing scan (for which a rising CV is eventually not healty and
you got a few kV arcs happening every now and then).

This is a budget cursuit, replacing many VCAs with pretty cheap CMOS
switches and extra control. However, the benefit with this approach is
that it scales better, it does not become very much more expensive as
you go up to 16 or 32 channels.

To make a infinitely increasing scan one would not be interested in
having the scan being linear to the CV, but the rise (or falltime) of
the scan to be linear with the CV, thus, it represents the scanning
frequency.

Basically this thing would remind one of a barber pole thing.

Anyway, with such a scanner you could redo one of the tricks that the
Hammond scanner does, frequency shifting the tone. This, shifted tone
is then added to create the beating effect. Designing a AP-filter
network that acheives the delays should be manegable. A gyrator or
leapfrog network is not a bad idea.

 j> Don's circuit is very elegant - can't await the full Hammond Vibrato 
 j> version !

That would be interesting indeed.

Cheers,
Magnus



From irish at eskimo.com  Sun Jan  3 11:28:10 1999
From: irish at eskimo.com (Irish)
Date: Sun, 3 Jan 1999 02:28:10 -0800
Subject: Hello All (introduction)
Message-ID: <99010302382502.30043@Pandemonium>

Hi there all, 
Most lists I've been on or run it's polite to introduce yourself when
you join. I've already posted this to AH, and this is going to two other related
lists. My apologies for those who see this more than once :) Pardon my cut and
paste. 

Everyone calls me Irish, really they do. I have been playing music on various
instruments since I was very small, so I can play practically anything. 

I have always liked electonic music, and recently sold all my guitar gear (that
I wan't playing anyway) to start making the music I like most. The inspiration
for this was DJ John Kelly and other 'desert' artists, although I don't
intend to do much DJ'ing, more like creation from scratch. 

So far I have a Korg Poly800 that I just put the filter mod on (along with a
midi thru port), and a wierd-ass item I'm hesitant to describe. It's a Miracle
piano, 49 keys, 6 built-in 'voices', velocity sensitive, and midi ports. I tried
to play a midi file on it via a SB and damned if it didn't grab the wav
samples and store them! It also now appears to have drum samples on ch8 (it
only has 8 midi channels). This will likely be the subject of several analogish
mods, once I learn how they're done. Any suggestions?  I also have a PC that has
never run anything but Linux in the last four years, equipped with a SB32 and
some promising software (Softwerk and kooBase). Also, a Korg DDD-5 should
appear soon. 
Anyone have (hardware) sequencer suggestions for someone on a budget? 

I was in the electronics manufacturing industry for several years, doing
everything from line assembly to department director. I have built everything
from Nintendos to heart defibrillators to industrial equipment. Needless to
say, I am quite at home with my Weller! And am looking forward to various DIY
mod projects. 
I no longer work in manufacturing (burnout); instead I have a 'low stress'
computer job (hah!). 

That's it. Sorry, I'm not normally this wordy; hope I didn't bore you to death
:) 

Irish



From mirwin1 at istar.ca  Sun Jan  3 11:53:51 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Sun, 03 Jan 1999 05:53:51 -0500
Subject: CA3046 exponential converter
References: <000801be3683$9b968060$841588cf@paults>
Message-ID: <368F4C3F.49BF4140@istar.ca>

The Moog Prodigy, Multimoog and Micromoog all use the "CA3046
Thermostat" circuit with no temperature compensating resistor (similar
to the AN-299 VCO). The rest of the VCO uses inexpensive dual BIFET op
amps (TL072 or LF353) with an LM393 dual comparator and a JFET for
capacitor reset. I duplicated and modified the Prodigy VCO design and it
works well-however I have never built a "Q81" thermistor compensated VCO
to compare it with.




From urekar.m at EUnet.yu  Sun Jan  3 12:36:55 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 03 Jan 1999 12:36:55 +0100
Subject: CA3046 exponential converter
References: <000801be3683$9b968060$841588cf@paults> <368F4C3F.49BF4140@istar.ca>
Message-ID: <368F5657.69AA@eunet.yu>

Michael B. Irwin wrote:
> 
> The Moog Prodigy, Multimoog and Micromoog all use the "CA3046
> Thermostat" circuit with no temperature compensating resistor (similar
> to the AN-299 VCO). The rest of the VCO uses inexpensive dual BIFET op
> amps (TL072 or LF353) with an LM393 dual comparator and a JFET for
> capacitor reset.

There's also Moog Rogue,but it uses just one transistor from the array
(like diode ?) and directly affects emitter current of expo pair
(someone can explain it better than me) and uses a PNP for cap reset.



marjan



From jhaible at primus-online.de  Sun Jan  3 17:30:46 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 3 Jan 1999 17:30:46 +0100
Subject: AW: CA3046 exponential converter
Message-ID: <19990103165925.18861.qmail@nuernberg2.pop.metronet.de>

> There's also Moog Rogue,but it uses just one transistor from the array
> (like diode ?) and directly affects emitter current of expo pair
> (someone can explain it better than me) and uses a PNP for cap reset.

I've seen this on some Moog synth (maybe the Rogue), too.
You don't really need an extra transistor for temperature sensing, if you
monitor the voltage across the transistor of the expo pair with the
reference 
current (the one inside the opamp feedback loop). This works perfectly
if you tie its base to GND and use the base of the "output" transistor for
the CV input. The only drawback of this method is that you will need a very
low impedance resistor divider for the CV in that case (best would be an
active divider, i.e. inverting omamp with gain << 1). That's because the
accuracy of the exponential function is very sensitive to a resistance in
the
base of the "output" transistor, while it's not so critical on the
reference
transistor (which operates at a fixed current anyway).

The good thing is that you can really build three tracking expo converters
from a single 3046: One reference transistor, 3 output transistors (with
individual CV's on their bases), and one heater transistor.

One Moog synth (The Rogue or the Micro ?) has a very well tracking VCF
built with this method, so it can serve as an additional, tuned VCO.

JH.



From jhaible at primus-online.de  Sun Jan  3 17:58:44 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 3 Jan 1999 17:58:44 +0100
Subject: AW: VCO-1C
Message-ID: <19990103165927.18861.qmail@nuernberg2.pop.metronet.de>

> Super simple 4 tranny unijunction VCO. May be the worlds
> smallest descret 1V/OCT VCO. Works a lot better than it looks.
> 
> http://www.mindspring.com/~vco/misc/pics/vco1c_sd.gif

I normally have mixed feelings about such minimal circuits: They are
tempting in their minimalistic elegance, but when you consider the
price of one single potentiometer of decent quality, there is not much
benefit from such low cost circuits anymore.

Normally, that is. But I wouldn't write this mail just to word this caveat.
Because I have found one reason to look at minimum parts count VCOs
meanwhile: That's for building a full polyphonic "ensemble" type keyboard
without divide-down circuitry, but with a lot of VCOs instead.

I have this old Roland VK-07 collecting dust, with a one contact per note
keyboard in almost perfect shape. I will try to sell the whole organ,
but if I don't get a good price for it, it's time to "modify" it a little.
That is,
keep the enclosure and replace the electronics.

What I have in mind is a VCO bank like the Korg VC-10 has it. A simple
linear, thyristor-based VCO per key, and a resistor string to apply LFO
modulation with slightly different strength to each VCO.

These VCOs don't have to cover a wide range (two octaves would be enough),
but they should be so stable that there is no need to re-tune individual
VCOs
at all. (Tuning the whole instrument is no problem with one common CV,
so some drift is ok as long as the whole VCO bank drifts in the same
way.)

I really don't know if I will actually start such a project, but I'd like
to
start collecting information about such instruments and their VCOs.
Any VC-10 owners: How stable is this thing ? (the internal VCOs)
Any Korg PE-1000 and PE-2000 owners: Do these instruments really have
individual VCOs, or are they divide-down units ? (I don't have schemos,
and what I heard about these instruments is contradictory.)
Any other instruments with individual VCOs ??

And last, not least: How temperature stable is your UJT VCO, Tom ?
(not asking about the expo converter, which is a low end compromise
no doubt - but the mere UJT / capacitor pair ?) And how does it perform
in comparison with a thyristor solution (like Korg) ?

JH.




From don at till.com  Sun Jan  3 19:02:41 1999
From: don at till.com (Don Tillman)
Date: Sun, 3 Jan 1999 10:02:41 -0800 (PST)
Subject: Don's interpolating scanner
In-Reply-To: <19990102231747.6493.qmail@nuernberg2.pop.metronet.de>
	(jhaible@primus-online.de)
Message-ID: <199901031802.KAA05912@shell9.ba.best.com>

   From: "jhaible" <jhaible at primus-online.de>
   Date: Sun, 3 Jan 1999 00:14:40 +0100

   Congrats to Don for further improoving the Scanner idea !

Thanks!

   Now I hope you will soon come up with a ready circuit for the full
   Hammond Chorus emulation !

I have some thoughts on emulating the Hammond Chorus; it's a very
interesting problem.  It requires some diagrams, so there'll be
another article soon I guess...

   I really like the idea of a smooth, and even variable transition. 
   Should have a real advantage in waveform generation.

Yeah, the biggest practical use for controlling the transition curve
shape is probably in waveform generation.

I've drawn up some ideas for voltage-controlled transition curve
shape, but I can't imagine a use for it right now.  Just a little too
featureful.

(Wait a second...  Using the scanner for waveform generation, changing
the transition curve shape is effectively a zero phase shift low pass
filter.  Hmmm...)

   You wrote about transistor matching. Did you simulate temperature
   effects as well ? (If there is a temperature effect on the waveform,
   one might compensate it with the shape control voltage ...)

The temperature effect is, I think, just a scale issue.  The scale of
the control voltage's range (the distance between the transistions)
is directly sensitive to the temperature change in degrees Kelvin.  So
like a lot of other synth circuitry, it probably only matters when
you're using this signal to tune a musical pitch.  (That's not going
to happen, right?  Or are there more uses for this thing?  :-) )

   I may have mentioned this before, but I also have worked out a
   simplified all-transistor / smooth transition version of the Scanner.

Nice!

  -- Don



From don at till.com  Sun Jan  3 19:28:44 1999
From: don at till.com (Don Tillman)
Date: Sun, 3 Jan 1999 10:28:44 -0800 (PST)
Subject: AW: Don's interpolating scanner
In-Reply-To: <199901030321.EAA22556@mail2.it.kth.se> (message from Magnus
	Danielson on Sun, 03 Jan 1999 04:21:57 +0100)
Message-ID: <199901031828.KAA10531@shell9.ba.best.com>

   From: Magnus Danielson <magnus at analogue.org>
   Date: Sun, 03 Jan 1999 04:21:57 +0100

   I agree, certainly an interesting piece of work!

Thanks!

   I have a little diffrent solution that does not require as many
   VCAs. In it's basic layout it only requires 2 VCAs. Let's consider a
   8-input scanner.

   First I would have two 8-to-1 analog muxes (4051's) to select two
   adjacent inputs, each being feed into the 2 VCAs. 

Yeah, this will work fine.  The big issue here is converting from an
input control voltage to the digital select lines for the mux and the
analog control voltages for the VCAs, and the circuitry to do this
accurately and without glitches is not easy.

But that's for a *linear* scanner, like the circuits JH and I did.

A *circular* scanner is where your approach becomes powerful.  A
circular scanner doesn't care about a scan control voltage so there's
no need to deal with that; a triangle wave oscillator and a counter
are all you need.  

A speed control voltage would change the frequency of the triangle
wave oscillator, and, yeah, through-zero is just begging, isn't it?

The original Hammond Chorus uses, clearly, a circular scanner.

  -- Don



From vco at mindspring.com  Sun Jan  3 20:13:58 1999
From: vco at mindspring.com (tomg)
Date: Sun, 03 Jan 1999 14:13:58 -0500
Subject: AW: VCO-1C
In-Reply-To: <19990103165927.18861.qmail@nuernberg2.pop.metronet.de>
Message-ID: <yam7672.2910.119058832@mail.mindspring.com>

On 03-Jan-99, jhaible wrote:
>> Super simple 4 tranny unijunction VCO. May be the worlds
>> smallest descret 1V/OCT VCO. Works a lot better than it looks.
>> 
>> http://www.mindspring.com/~vco/misc/pics/vco1c_sd.gif

>I normally have mixed feelings about such minimal circuits: They are
>tempting in their minimalistic elegance, but when you consider the
>price of one single potentiometer of decent quality, there is not much
>benefit from such low cost circuits anymore.

>Normally, that is. But I wouldn't write this mail just to word this caveat.
>Because I have found one reason to look at minimum parts count VCOs
>meanwhile: That's for building a full polyphonic "ensemble" type keyboard
>without divide-down circuitry, but with a lot of VCOs instead.

[snip]

>And last, not least: How temperature stable is your UJT VCO, Tom ?
>(not asking about the expo converter, which is a low end compromise
>no doubt - but the mere UJT / capacitor pair ?) And how does it perform
>in comparison with a thyristor solution (like Korg) ?

>JH.

I OTOH love minimal stuff and think this is neet! Sort of a
novelty circuit. Killer at the low end. rattles the rafters!

Would be great for a SHF vco to divide and shape. A micro-synth
two vco thing wouldn't be too bad. Also good as a single voice 
bass bomber! 

If you did the proper things to it I think it would be fine.
Like a pnp pair, 1K temco, poly cap, sealed trimmers ect...
However that would cost you a fortune.

Like it is NO WAY!... This thing blows with the wind. A bank
of 36/48 of these things would drive you nuts. Best to re-think
that divide-down idea.

-tg








From don at till.com  Sun Jan  3 21:21:30 1999
From: don at till.com (Don Tillman)
Date: Sun, 3 Jan 1999 12:21:30 -0800 (PST)
Subject: Don's interpolating scanner
In-Reply-To: <199901031828.KAA10531@shell9.ba.best.com> (message from Don
	Tillman on Sun, 3 Jan 1999 10:28:44 -0800 (PST))
Message-ID: <199901032021.MAA01070@shell9.ba.best.com>

   Date: Sun, 3 Jan 1999 10:28:44 -0800 (PST)
   From: Don Tillman <don at till.com>

   The original Hammond Chorus uses, clearly, a circular scanner.

[don't leave it hanging, Don...]

While the Hammond Chorus uses a circular scanner, that's somewhat
deceptive -- the scanner inputs are connected mapping back and forth
across a line.  Specifically the delay line.  So there's no barber
pole effect going on there or anything like that.

A circular scanner would really win for waveform generation; the
waveform just rotates through 360 degrees with no glitch for a
sawtooth reset.  I'll suggest that a circular scanner with voltage
controlled transition shape and through-zero FM would be a mighty
impressive VCO module.  Hmmm....

  -- Don









From idreamin3d at toad.net  Sun Jan  3 22:22:54 1999
From: idreamin3d at toad.net (I Dream In 3D)
Date: Sun, 03 Jan 1999 16:22:54 -0500
Subject: Looking for joysticks...
Message-ID: <3.0.1.32.19990103162254.006b2b98@toad.net>


Where can I find those little joysticks (X-Y Controllers).  I'm building a
synth, and I want to integrate a joystick into my design, but I can't find
a supplier for these anywhere.  I don't want to rape an old PC joystick or
anything...I want to use all new parts because I am building a prototype to
be viewed by investors.  Thanks for your help...

idreamin3d at toad.net




From mike_clancy at excite.com  Sun Jan  3 22:47:55 1999
From: mike_clancy at excite.com (Michael Clancy)
Date: Sun, 03 Jan 1999 13:47:55 PST
Subject: FS:Paia (and other) kits
Message-ID: <915400075.27492.229@excite.com>






_______________________________________________________
Get your free, private email at http://mail.excite.com/



From mike_clancy at excite.com  Sun Jan  3 23:08:16 1999
From: mike_clancy at excite.com (Michael Clancy)
Date: Sun, 03 Jan 1999 14:08:16 PST
Subject: FS:Paia (and other) kits
Message-ID: <915401296.28083.147@excite.com>

Paia Submix Master w/panel - completed, but I haven't started the power
supply kit yet.

Paia MIDI Studio Interface w/panel - haven't started yet.

Audio Visual Imagery MIDI Light Controller - got the printed circuit board
and about half of the components. Haven't started yet.

I would like to sell all three kits to someone with a little more ambition
than me. Please make an offer at:

Clancy.Michael at worldnet.att.net

Thanks.

Mike




_______________________________________________________
Get your free, private email at http://mail.excite.com/



From magnus at analogue.org  Sun Jan  3 23:59:44 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 03 Jan 1999 23:59:44 +0100
Subject: AW: Don's interpolating scanner
In-Reply-To: Your message of "Sun, 3 Jan 1999 10:28:44 -0800 (PST)"
References: <199901031828.KAA10531@shell9.ba.best.com>
Message-ID: <199901032259.XAA27500@mail2.it.kth.se>

>>>>> "DT" == Don Tillman <don at till.com> writes:

Hi!

 DT>    From: Magnus Danielson <magnus at analogue.org>
 DT>    Date: Sun, 03 Jan 1999 04:21:57 +0100

 DT>    I agree, certainly an interesting piece of work!

 DT> Thanks!

Anytime!

 DT>    I have a little diffrent solution that does not require as many
 DT>    VCAs. In it's basic layout it only requires 2 VCAs. Let's consider a
 DT>    8-input scanner.

 DT>    First I would have two 8-to-1 analog muxes (4051's) to select two
 DT>    adjacent inputs, each being feed into the 2 VCAs. 

 DT> Yeah, this will work fine.  The big issue here is converting from an
 DT> input control voltage to the digital select lines for the mux and the
 DT> analog control voltages for the VCAs, and the circuitry to do this
 DT> accurately and without glitches is not easy.

Sure. But once you have reduced the audio path you can do this.

 DT> But that's for a *linear* scanner, like the circuits JH and I did.

Right.

 DT> A *circular* scanner is where your approach becomes powerful.  A
 DT> circular scanner doesn't care about a scan control voltage so there's
 DT> no need to deal with that; a triangle wave oscillator and a counter
 DT> are all you need.  

Right again.

 DT> A speed control voltage would change the frequency of the triangle
 DT> wave oscillator, and, yeah, through-zero is just begging, isn't it?

Sure is.

 DT> The original Hammond Chorus uses, clearly, a circular scanner.

It does. Hooked to the synchronous motor shaft, you switch depth (and
those shift amount) by selecting how the scanner is hooked to the
AP-delay line.

Now, what I have been thinking lately is how one could combine the
linear and rotating scanners, so you have a linear (phi) and rotation
speed (omega) modulation input to a common scanning core.

To do this you would have to first transform the rotation speed
(omega) into a wrapped ramp (covering the full range), then add the
linear modulation (phi) and put this through a wrapper again. I
suppose that one could do this in the analog domain, but I really
think it is better done in the digital domain (like a PIC or so).
Could be done in analog as well, but it becomes a bit trickier.

Cheers,
Magnus



From vco at mindspring.com  Mon Jan  4 00:13:30 1999
From: vco at mindspring.com (tomg)
Date: Sun, 03 Jan 1999 18:13:30 -0500
Subject: AW: VCO-1C #2
In-Reply-To: <yam7672.2910.119058832@mail.mindspring.com>
Message-ID: <yam7672.1544.118972152@mail.mindspring.com>


>>And last, not least: How temperature stable is your UJT VCO, Tom ?
>>(not asking about the expo converter, which is a low end compromise
>>no doubt - but the mere UJT / capacitor pair ?) And how does it perform
>>in comparison with a thyristor solution (like Korg) ?

>>JH.

>Like it is NO WAY!... This thing blows with the wind. A bank
>of 36/48 of these things would drive you nuts. Best to re-think
>that divide-down idea.

>-tg

If you really are serious about this. Look at the VCO-3A 
again. I used it in the MM and Mini4. After considering 
your idea a little more, I think this might actually be 
a solution. 

Temp-stability is good. It would still require at least a tempco 
and maybe 3046s if you were going to gang them up.

This is (no offence...really) a pretty nutty idea. Having only 12/16 
CEM3340s in a poly they used a cpu to keep 'em almost in tune, some 
of the time, and those were Curtis chips.  

-tg (I push my tune buttons all the time)



 
  









From jhaible at primus-online.de  Mon Jan  4 00:49:02 1999
From: jhaible at primus-online.de (jhaible)
Date: Mon, 4 Jan 1999 00:49:02 +0100
Subject: circular interpolating scanner
Message-ID: <19990104001721.24894.qmail@nuernberg2.pop.metronet.de>

> While the Hammond Chorus uses a circular scanner, that's somewhat
> deceptive -- the scanner inputs are connected mapping back and forth
> across a line.  Specifically the delay line.  So there's no barber
> pole effect going on there or anything like that.
> 
> A circular scanner would really win for waveform generation; the
> waveform just rotates through 360 degrees with no glitch for a
> sawtooth reset.  I'll suggest that a circular scanner with voltage
> controlled transition shape and through-zero FM would be a mighty
> impressive VCO module.  Hmmm....
> 
>   -- Don

I think the Hammond circular scanner with "mapping back and forth"
can be emulated with a linear scanner of *half* the length and triangle
(not saw) input.
BTW, I rarely use my scanner with saw input even for waveform generation.
I triangle has prooved a much more effective source. Of course the sliders
do not represent the waveform then, but you rather draw the transfer
courve.
Think of a Fuzz box with graphical input for the clipping function. You
normally
drive it with a low harmonic content input wave, like sine, or triangle (or
electric
guitar).

JH.



From jhaible at primus-online.de  Mon Jan  4 00:57:47 1999
From: jhaible at primus-online.de (jhaible)
Date: Mon, 4 Jan 1999 00:57:47 +0100
Subject: AW: VCO-1C
Message-ID: <19990104001724.24894.qmail@nuernberg2.pop.metronet.de>

> Talking about old Korgs, is there any one besides me who like
> and use the MS20, JX3p VCA design?

I still think that it's responsible for the rather bad SNR of many Korg
Synths. I never have made tests on a MS-20 (and here the VCF probably
contributes a lot of noise, too), but I once replaced the VCA in a 
Mono/Poly with a SSM2020 VCA, and it was a *big* difference.
No more annoying hiss on low bass notes.

BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
and they have very different transfer courves when overdriven.
(1-transistor version is only clipping one side of the signal)

Interesting for sure, but you'd rather have the *option* of a low noise
VCA, at least.

JH.



From jhaible at primus-online.de  Mon Jan  4 01:01:23 1999
From: jhaible at primus-online.de (jhaible)
Date: Mon, 4 Jan 1999 01:01:23 +0100
Subject: AW: CA3046 exponential converter
Message-ID: <19990104001725.24894.qmail@nuernberg2.pop.metronet.de>

> Hmm, are you refering to my design around the shemo i sent
> to you OR have you seen this app in a other machines?Where one
> would use the reamining two transistors as an oven as i did.
> If so ,where is it done ,besides the Rouge and the Micro?

I'd say it probably was the Micro (it's been some time since I looked).
There even was a trimmer to adjust the temperature. But I don't want
to spread misinformation here.

JH.



From jhaible at primus-online.de  Mon Jan  4 01:14:51 1999
From: jhaible at primus-online.de (jhaible)
Date: Mon, 4 Jan 1999 01:14:51 +0100
Subject: VCO-1C #2
Message-ID: <19990104001734.24894.qmail@nuernberg2.pop.metronet.de>

> If you really are serious about this. Look at the VCO-3A 
> again. I used it in the MM and Mini4. After considering 
> your idea a little more, I think this might actually be 
> a solution. 
> 
> Temp-stability is good. It would still require at least a tempco 
> and maybe 3046s if you were going to gang them up.
> 
> This is (no offence...really) a pretty nutty idea. Having only 12/16 
> CEM3340s in a poly they used a cpu to keep 'em almost in tune, some 
> of the time, and those were Curtis chips.  

No, no, no - as I said, I would build *linear* VCOs and nothing else.
Why fooling around with expo converters when each VCO is dedicated
to one note on the keyboard anyway ?
(My question was about the stability of the VCO *core*, not the expo 
converter.)
And speaking of polysynths, my CS-50 is perfectly in tune for a year 
or more, without the need of any autotune, and even without touching
the Manual Fine Tune Knob ! (And I bet a CS-80 wouldn't be much worse
if it wouldn't produce that much heat on its own !)

JH.



From vco at mindspring.com  Mon Jan  4 02:49:01 1999
From: vco at mindspring.com (tomg)
Date: Sun, 03 Jan 1999 20:49:01 -0500
Subject: VCO-1C #2
In-Reply-To: <19990104001734.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <yam7672.78.118825512@mail.mindspring.com>

On 03-Jan-99, jhaible wrote:
>> If you really are serious about this. Look at the VCO-3A 
>> again. I used it in the MM and Mini4. After considering 
>> your idea a little more, I think this might actually be 
>> a solution. 
>> 
>> Temp-stability is good. It would still require at least a tempco 
>> and maybe 3046s if you were going to gang them up.
>> 
>> This is (no offence...really) a pretty nutty idea. Having only 12/16 
>> CEM3340s in a poly they used a cpu to keep 'em almost in tune, some 
>> of the time, and those were Curtis chips.  

>No, no, no - as I said, I would build *linear* VCOs and nothing else.
>Why fooling around with expo converters when each VCO is dedicated
>to one note on the keyboard anyway ?
>(My question was about the stability of the VCO *core*, not the expo 
>converter.)
>And speaking of polysynths, my CS-50 is perfectly in tune for a year 
>or more, without the need of any autotune, and even without touching
>the Manual Fine Tune Knob ! (And I bet a CS-80 wouldn't be much worse
>if it wouldn't produce that much heat on its own !)

>JH.

Ohhhh...I see (duh) maybe it's not so nutz after all...:-)
Sorry. 

In that case I would like to sell you on the 5A ota type 
that's just one LM13600/700, 5 resistors and one cap. 
About $1.50 a key. Probibly the most stable of the bunch.
and very pretty waveforms. You could set up a bank of 
analog switches and flip between the tri/sq. Might even
work out to be cheeper than some of the TOC chips I've
seen for sale these days..

I think the 1C is pretty cool and it's very small but I 
don't think I would use it for what you want to do.

Hope this helps.

poly stuff?

My jp-6 is better than my p-600 but even the mx-6 and
mx-1000 need tuning once in a while and they use DCOs.
Most of the other stuff is right on all the time. Once
in a blue moon the ex8000 (also DCOs) needs a tweek.

-tg




 




From zzynt at swipnet.se  Mon Jan  4 06:25:07 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 03 Jan 1999 21:25:07 -0800
Subject: AW: VCO-1C
References: <19990103165927.18861.qmail@nuernberg2.pop.metronet.de>
Message-ID: <369050B3.B0@swipnet.se>

jhaible wrote:

> 
> What I have in mind is a VCO bank like the Korg VC-10 has it. A simple
> linear, thyristor-based VCO per key, and a resistor string to apply LFO
> modulation with slightly different strength to each VCO.
> start collecting information about such instruments and their VCOs.
> Any VC-10 owners: How stable is this thing ? (the internal VCOs)
> Any Korg PE-1000 and PE-2000 owners: Do these instruments really have
> individual VCOs, or are they divide-down units ? (I don't have schemos,
> and what I heard about these instruments is contradictory.)
> Any other instruments with individual VCOs ??


Talking about old Korgs, is there any one besides me who like
and use the MS20, JX3p VCA design?

Have any one done any serious measurements between a CA3080
and this transistor OP amp VCA.

Some history:
If i can remember this right, the UJT VCO was a swedish invention
back in the 50/60's and then was the basis for the design of the
4151/331 IC.

BJ



From theremin1 at worldnet.att.net  Mon Jan  4 06:36:09 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Sun, 3 Jan 1999 21:36:09 -0800
Subject: Looking for joysticks...
Message-ID: <001d01be37a4$227f87e0$b77b4e0c@hpcustomer>

See Allied Electronic's on-line catalog:
http://www.allied.avnet.com/catalog_pages/646.pdf
(bottom left of page).
These are Maurey joysticks, and they are costly!
Then again, so are good discrete potentiometers,
these days.

-Art

-----Original Message-----
From: I Dream In 3D <idreamin3d at toad.net>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Sunday, January 03, 1999 3:34 PM
Subject: Looking for joysticks...


>
>Where can I find those little joysticks (X-Y Controllers).  I'm building a
>synth, and I want to integrate a joystick into my design, but I can't find
>a supplier for these anywhere.  I don't want to rape an old PC joystick or
>anything...I want to use all new parts because I am building a prototype to
>be viewed by investors.  Thanks for your help...
>
>idreamin3d at toad.net
>
>




From zzynt at swipnet.se  Mon Jan  4 06:39:53 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 03 Jan 1999 21:39:53 -0800
Subject: AW: CA3046 exponential converter
References: <19990103165925.18861.qmail@nuernberg2.pop.metronet.de>
Message-ID: <36905429.4B26@swipnet.se>

jhaible wrote:
> I've seen this on some Moog synth (maybe the Rogue), too.
> You don't really need an extra transistor for temperature sensing, if you
> monitor the voltage across the transistor of the expo pair with the
> reference
> current (the one inside the opamp feedback loop). This works perfectly
> if you tie its base to GND and use the base of the "output" transistor for
> the CV input. The only drawback of this method is that you will need a very
> low impedance resistor divider for the CV in that case (best would be an
> active divider, i.e. inverting omamp with gain << 1). That's because the
> accuracy of the exponential function is very sensitive to a resistance in
> the
> base of the "output" transistor, while it's not so critical on the
> reference
> transistor (which operates at a fixed current anyway).
> 
> The good thing is that you can really build three tracking expo converters
> from a single 3046: One reference transistor, 3 output transistors (with
> individual CV's on their bases), and one heater transistor.
> 
> One Moog synth (The Rogue or the Micro ?) has a very well tracking VCF
> built with this method, so it can serve as an additional, tuned VCO.
> 
> JH.

Hmm, are you refering to my design around the shemo i sent
to you OR have you seen this app in a other machines?Where one
would use the reamining two transistors as an oven as i did.
If so ,where is it done ,besides the Rouge and the Micro?

Regarding to the Rouge, is int the Rouge using a 100ohm tempco
resistors on the base of the expo transistors as temp comp!

This oven thing is nice, the Moog Source uses this scheme
but with a over designed oven and sensing circuit, but the VCOs
are rock solid stable, i vas fooling around with one of these
machines back in the mid 80 and was impressed with the stability
and since then i only do Oven VCO's.

BJ



From zzynt at swipnet.se  Mon Jan  4 06:51:43 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 03 Jan 1999 21:51:43 -0800
Subject: Filters?
References: <19990103165925.18861.qmail@nuernberg2.pop.metronet.de>
Message-ID: <369056EF.559B@swipnet.se>

Has anyone a mp3 or a wave file of the sound of a EMS filter
and a odinary Moog LP filter?Diode ladder versus TR ladder!

Im interested in the audio difference between those filter types!

Anyone who has done a close comparision between them
and have a opinion on the sonic differences?

BJ



From vco at mindspring.com  Mon Jan  4 07:38:27 1999
From: vco at mindspring.com (tomg)
Date: Mon, 04 Jan 1999 01:38:27 -0500
Subject: VCO-1C #2
In-Reply-To: <3690A9AF.47E6@swipnet.se>
Message-ID: <yam7673.1350.118778808@mail.mindspring.com>

On 04-Jan-99, BJ wrote:
>> My jp-6 is better than my p-600 but even the mx-6 and
>> mx-1000 need tuning once in a while and they use DCOs.
>> Most of the other stuff is right on all the time. Once
>> in a blue moon the ex8000 (also DCOs) needs a tweek.
>> 
>> -tg
>> 
>> 

>What kind of DCO is it in the Mx-1000?
>1000 dollars  that they used the 8253/4 counter!!

>Any prescaler?

>BJ

It's the CEM3396. Actually a complete synth voice on a chip.
It would be very cool for one of the bit masters to figure
out a way to use this chip without a pile of hard/software.

Maybe using flash converters or a basic stamp???? Anyway
Paul S. has a bunch. Sure would be nice. One chip and a 
little i/o stuff per voice....

-tg







From vco at mindspring.com  Mon Jan  4 07:53:37 1999
From: vco at mindspring.com (tomg)
Date: Mon, 04 Jan 1999 01:53:37 -0500
Subject: AW: VCO-1C
In-Reply-To: <369090A2.35AB@swipnet.se>
Message-ID: <yam7673.1893.118778808@mail.mindspring.com>

On 04-Jan-99, BJ wrote:
>jhaible wrote:
>> 
>> > Talking about old Korgs, is there any one besides me who like
>> > and use the MS20, JX3p VCA design?
>> 
>> I still think that it's responsible for the rather bad SNR of many Korg
>> Synths. I never have made tests on a MS-20 (and here the VCF probably
>> contributes a lot of noise, too), but I once replaced the VCA in a
>> Mono/Poly with a SSM2020 VCA, and it was a *big* difference.
>> No more annoying hiss on low bass notes.

>Actually i dont find the MS20 noisy it is in fact rater silent,
>but on the other hand the Monopoly is wery noisy, i have owned both.

>The one transistor VCA is  used in the JX3P and JX8P and they are
>not particular noisy i think!
> 
>> BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
>> and they have very different transfer courves when overdriven.
>> (1-transistor version is only clipping one side of the signal)
>> 
>> Interesting for sure, but you'd rather have the *option* of a low noise
>> VCA, at least.

>Yes, if one would overdrive the one transistor version at some 
>levels one get a sinus wave ot of a triangle wave.

>BJ

This is not really a VCA it's more of an attenuator. I call it
an emitter pass attenuator after the power supply regulator
of the same configuration. 

It drags the signal very close to ground. That's why it's 
followed by a op-amp set at a gain of 100,000 - 220,000. 
I think it kills the balls on the siginal. It's like turning
a level pot up to 5% then amping the hell out of it. Depending 
on the op-amp it can add a ton of noise set for that much gain. 
It's pretty close to fuzz-tone levels.

It works, it's simple and it's cheep, not bad but not 
really very good.

-tg







 




From vco at mindspring.com  Mon Jan  4 08:04:54 1999
From: vco at mindspring.com (tomg)
Date: Mon, 04 Jan 1999 02:04:54 -0500
Subject: Minimum Parts VCO was VCO-1C
In-Reply-To: <19990104001734.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <yam7673.2720.118778808@mail.mindspring.com>



I never posted this because I didn't finish testing
it completely. If you don't look at the waveforms
it sounds like a saw but they look like a bad tri.

If you get rid of the exp-conv's it leaves 1/2 a
13600 one cap 2 diodes and 4 resistors. Reduces
the cost to about $.70 per key. May be just what
you want...might not be though.


http://www.mindspring.com/~vco/misc/pics/vco6a_sd.gif

-tg





From hugo.haesaert at skynet.be  Mon Jan  4 08:20:57 1999
From: hugo.haesaert at skynet.be (Hugo Haesaert)
Date: Mon, 4 Jan 1999 08:20:57 +0100
Subject: Looking for joysticks...
In-Reply-To: <3.0.1.32.19990103162254.006b2b98@toad.net>
Message-ID: <199901040711.IAA23143@sunsoap.skynet.be>

Hi All !


Anybody tried to use those radio control joysticks ?

You might try Korg service dept .  The Wavestation and the WS AD both 
use 'em and these machines are not too old .

Just some thoughts .

Happy New Year .


Keep 'em oscillating :)


Hugo
=



From zzynt at swipnet.se  Mon Jan  4 08:26:10 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 03 Jan 1999 23:26:10 -0800
Subject: AW: CA3046 exponential converter
References: <19990103165925.18861.qmail@nuernberg2.pop.metronet.de> <36905429.4B26@swipnet.se>
Message-ID: <36906D12.6063@swipnet.se>

BJ wrote:
> 
> jhaible wrote:
> > I've seen this on some Moog synth (maybe the Rogue), too.
> > You don't really need an extra transistor for temperature sensing, if you
> > monitor the voltage across the transistor of the expo pair with the
> > reference
> > current (the one inside the opamp feedback loop). This works perfectly
> > if you tie its base to GND and use the base of the "output" transistor for
> > the CV input. The only drawback of this method is that you will need a very
> > low impedance resistor divider for the CV in that case (best would be an
> > active divider, i.e. inverting omamp with gain << 1). That's because the
> > accuracy of the exponential function is very sensitive to a resistance in
> > the
> > base of the "output" transistor, while it's not so critical on the
> > reference
> > transistor (which operates at a fixed current anyway).
> >
> > The good thing is that you can really build three tracking expo converters
> > from a single 3046: One reference transistor, 3 output transistors (with
> > individual CV's on their bases), and one heater transistor.
> >
> > One Moog synth (The Rogue or the Micro ?) has a very well tracking VCF
> > built with this method, so it can serve as an additional, tuned VCO.
> >
> > JH.
> 
> Hmm, are you refering to my design around the shemo i sent
> to you OR have you seen this app in a other machines?Where one
> would use the reamining two transistors as an oven as i did.
> If so ,where is it done ,besides the Rouge and the Micro?

The schemo of my proposal for this tripple expoconverter are found at:
http://home8.swipnet.se/~w-88660/schpcb.htm

Any reports regarding to faults or performance upgrading are welcome!

BJ



From jorgen.bergfors at idg.se  Mon Jan  4 09:28:19 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 4 Jan 1999 9:28:19 +0100
Subject: Tempco measurements
Message-ID: <TFSYFSTW@idg.se>

Happy new year DIYers!

During the christmas break I made some measurements on my ASM-1 clone VCO (I made my own board, otherwise it is identical to the ASM-1). It has a SMD tempco resistor ($0.60) and a BC847BS dual SMD transistor ($0.20) mounted on a hybride module and covered with Araldite. The module fits in an ordinary 8 pin DIP IC-socket.The timing capacitor is a Wima FKP2 (Polypropylene/metal film).
I put the VCO board (size 50 x 75 mm, 2 x 3") in a shoe box and put on the lid. 20 cm (8") from the box I placed a 300 watt infrared heater. After 15 minutes the temperature inside the box had rised from 24 to 34 degrees C.
With the tempco the frequency of the VCO increased from 518 to 523 Hz. This corresponds to 17 cents or 1/6 of a semitone. With the tempco replaced by a normal 1% metal film resistor, the frequency increased from 424 to 470 Hz. That's 190 cents or almost two semitones.

I don't know how this compares with other VCOs but at least the tempco resistor makes a big difference for sure! Anyone else who have made similar measurements?

/Jorgen




From vco at mindspring.com  Mon Jan  4 09:33:25 1999
From: vco at mindspring.com (tomg)
Date: Mon, 04 Jan 1999 03:33:25 -0500
Subject: Looking for joysticks...
In-Reply-To: <199901040711.IAA23143@sunsoap.skynet.be>
Message-ID: <yam7673.1280.118955488@mail.mindspring.com>

On 04-Jan-99, Hugo Haesaert wrote:
>Hi All !


>Anybody tried to use those radio control joysticks ?

>You might try Korg service dept .  The Wavestation and the WS AD both 
>use 'em and these machines are not too old .

>Just some thoughts .

>Happy New Year .


>Keep 'em oscillating :)


>Hugo
>=

Go to the thrift store. Goodwill, Salvation Army..ect.
Look for an apple II or color computer joystick. You
might have to look a little but cost is normaly in the
$2-3 range.

-tg





From zzynt at swipnet.se  Mon Jan  4 10:57:54 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 01:57:54 -0800
Subject: AW: VCO-1C
References: <19990104001724.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <369090A2.35AB@swipnet.se>

jhaible wrote:
> 
> > Talking about old Korgs, is there any one besides me who like
> > and use the MS20, JX3p VCA design?
> 
> I still think that it's responsible for the rather bad SNR of many Korg
> Synths. I never have made tests on a MS-20 (and here the VCF probably
> contributes a lot of noise, too), but I once replaced the VCA in a
> Mono/Poly with a SSM2020 VCA, and it was a *big* difference.
> No more annoying hiss on low bass notes.

Actually i dont find the MS20 noisy it is in fact rater silent,
but on the other hand the Monopoly is wery noisy, i have owned both.

The one transistor VCA is  used in the JX3P and JX8P and they are
not particular noisy i think!
 
> BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
> and they have very different transfer courves when overdriven.
> (1-transistor version is only clipping one side of the signal)
> 
> Interesting for sure, but you'd rather have the *option* of a low noise
> VCA, at least.

Yes, if one would overdrive the one transistor version at some 
levels one get a sinus wave ot of a triangle wave.

BJ



From Juergen.Haible at nbgm.siemens.de  Mon Jan  4 12:00:46 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 4 Jan 1999 12:00:46 +0100 
Subject: AW: AW: VCO-1C
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582011513C0@nbgm336a.nbgm.siemens.de>

	>Actually i dont find the MS20 noisy it is in fact rater silent,
	>but on the other hand the Monopoly is wery noisy, i have owned
both.

Was this an early MS-20 or a later model ?
I only played early ones (with Korg-35 ICs), and they were
quite noisy (more than my Mono/Poly). I never played
a later MS-20, but they have LM13600-based filters and
a deemphasis (470us, 6dB) after the VCA (where is the
preemphase counterpart ??), and they are said to be 
more quiet.

	>The one transistor VCA is  used in the JX3P and JX8P and they are
	>not particular noisy i think!

Never seen these schemos. Are they anywhere on the web?
>  
	JH.



From rsowa at WizjaTV.pl  Mon Jan  4 12:32:58 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 4 Jan 1999 12:32:58 +0100 
Subject: ODP: Looking for joysticks...
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6842@demon>

Hi all,

Well, I've seen various jousticks in my ELFA catalog.
Try http://www.elfa.se
They have cheapo and expensive ones, 
with spring return or not, or even 3D! - X, Y and rotary knob in the stick
(also with spring return).
or if you are wealthy, why not use inductive pot-free model...

Be prepared for little bit higher prices tho...

Roman

> -----Oryginalna wiadomo??-----
> Od:	I Dream In 3D [SMTP:idreamin3d at toad.net]
> Wys?ano:	3 stycznia 1999 22:23
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Looking for joysticks...
> 
> 
> Where can I find those little joysticks (X-Y Controllers).  I'm building a
> synth, and I want to integrate a joystick into my design, but I can't find
> a supplier for these anywhere.  I don't want to rape an old PC joystick or
> anything...I want to use all new parts because I am building a prototype
> to
> be viewed by investors.  Thanks for your help...
> 
> idreamin3d at toad.net



From zzynt at swipnet.se  Mon Jan  4 12:44:47 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 03:44:47 -0800
Subject: VCO-1C #2
References: <yam7672.78.118825512@mail.mindspring.com>
Message-ID: <3690A9AF.47E6@swipnet.se>

> My jp-6 is better than my p-600 but even the mx-6 and
> mx-1000 need tuning once in a while and they use DCOs.
> Most of the other stuff is right on all the time. Once
> in a blue moon the ex8000 (also DCOs) needs a tweek.
> 
> -tg
> 
> 

What kind of DCO is it in the Mx-1000?
1000 dollars  that they used the 8253/4 counter!!

Any prescaler?

BJ



From urekar.m at EUnet.yu  Mon Jan  4 12:52:32 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Mon, 04 Jan 1999 12:52:32 +0100
Subject: AW: VCO-1C
References: <19990104001724.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <3690AB80.652F@eunet.yu>

> I still think that it's responsible for the rather bad SNR of many Korg
> Synths. 

Polysix also uses such VCA (with two transistors) and it sounds rather
noisy to me (even with effect section turned off),but IMO it's not
so bad in final mix.


> BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
> and they have very different transfer courves when overdriven.
> (1-transistor version is only clipping one side of the signal)


as in MS20 (old version with korg vcf chip uses 1,and ota version vcf
uses 2 
transistors in VCA). But it sounds so great to me (ota version)... 



marjan



From urekar.m at EUnet.yu  Mon Jan  4 12:52:40 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Mon, 04 Jan 1999 12:52:40 +0100
Subject: AW: CA3046 exponential converter
References: <19990104001725.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <3690AB88.4762@eunet.yu>

> > Hmm, are you refering to my design around the shemo i sent
> > to you OR have you seen this app in a other machines?Where one
> > would use the reamining two transistors as an oven as i did.
> > If so ,where is it done ,besides the Rouge and the Micro?
> 
> I'd say it probably was the Micro (it's been some time since I looked).
> There even was a trimmer to adjust the temperature. But I don't want
> to spread misinformation here.

Rogue uses 1 tranny heather method,2 for vco expos,1 for vcf,1 not
used,2 100R 
tempcos for vcos
Micro uses 2 for standard expo for vco, 1 for heater,1 for vcf and 1 for 
current source,temp trim for 56'C adjust
Multi has 2 arrays for vcos, each: 2 for expo conv, 1 heater+temp trim,2
unused
Prodigy uses 2 for expo,1 unused,2 for sensor diode and heater (oven)
and temp
trim (also in Doepfer modular discrete vco)


marjan



From urekar.m at EUnet.yu  Mon Jan  4 12:52:44 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Mon, 04 Jan 1999 12:52:44 +0100
Subject: VCO-1C #2
References: <19990104001734.24894.qmail@nuernberg2.pop.metronet.de>
Message-ID: <3690AB79.667C@eunet.yu>

jhaible wrote:

> No, no, no - as I said, I would build *linear* VCOs and nothing else.
> Why fooling around with expo converters when each VCO is dedicated
> to one note on the keyboard anyway ?

How about linear vco from moog taurus I ?

>(My question was about the stability of the VCO *core*, not the expo 
>converter.)


sounds ok in my polysix (discrete vcos similar to ms20/tb303)


marjan



From rsowa at WizjaTV.pl  Mon Jan  4 13:22:00 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 4 Jan 1999 13:22:00 +0100 
Subject: ODP: 6-pole switched capacitor filter "Q's" (literally)
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6845@demon>

Just thinging loud...

Guess this filter is inverting phase by 180 deg just above
cutoff frequency. So if you invert its output once again
and feed its input with it, I say it would be resonant at that frequency.

And I don't see why it should freak out just because it is SC filter.
but anyway I'd put simple RC at output.

Roman

> -----Oryginalna wiadomo??-----
> Od:	Duane R Balvage [SMTP:dbalvage at ptdcs2.ra.intel.com]
> Wys?ano:	31 grudnia 1998 22:38
> Do:	Synth-DIY
> Temat:	6-pole switched capacitor filter "Q's" (literally)
> 
> Hello all -
> 
> I have ordered some switched cap 6-pole butterworth filter chips from
> National Semi... I originally got them to replace the anti-aliasing
> filter and reconstruction filter in my Prophet-2000 sampler, but I got a
> (strange) idea...
> 
> Can you loop the output through a VCA or variable attenuator back to the
> input for a resonance control? Or will the switched-cap filter freeak
> out if you do that? Anyone tried this? I don't have the chips yet, but I
> was thinking of trying this.
> 
> 				- Duane
> -- 
>    "That boy's got a mouth like a cannon ... Always shootin' it off..."
>                                 
>                              - Foghorn Leghorn
>                       ________________________________
>                      / o o oo              o ooo o   /\
>        -------------/ ////  Duane R. Balvage   //// / /---------
>                    /    _________________________  / /
>                   / // / // /// // /// // /// / / / /
>                  /___ //////////////////////////_/ /
>                  \____\________________________\_\/
> 
>                      Intel Corporation, RA1-303
>                    Portland Technology Development
>        =========================================================
> 
>               Phone: (503) 613-8055    FAX: (503) 613-8261
>                    E-Mail: dbalvage at ptdcs2.intel.com



From jlarryh at iquest.net  Mon Jan  4 13:43:31 1999
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Mon, 4 Jan 1999 06:43:31 -0600
Subject: Looking for joysticks...
Message-ID: <199901041137.MAA09327@mailhost.bpa.nl>

Be prepared to PAY if you get these kind of parts from Korg.  I have
several of their keyboards.  examples of prices in USD.

720K disk drive for DSS-1 $200 (should be less than $50)
Power supply board for T1 $175 (should have been under $75 max).

Larry Hendry

----------
> From: Hugo Haesaert <hugo.haesaert at skynet.be>
> 
> You might try Korg service dept .  The Wavestation and the WS AD both 
> use 'em and these machines are not too old .




From Juergen.Haible at nbgm.siemens.de  Mon Jan  4 15:13:10 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 4 Jan 1999 15:13:10 +0100 
Subject: AW: AW: VCO-1C
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582011514B5@nbgm336a.nbgm.siemens.de>

	>Polysix also uses such VCA (with two transistors) and it sounds
rather
	>noisy to me (even with effect section turned off),but IMO it's not
	>so bad in final mix.

Same for the Mono/Poly. It's grat for all kind of Lead sounds,
and you won't notice the noise. But for low bass sounds, or
dark pad sounds, a good VCA makes a great difference.
Not just in theory - I made a direct A / B comparison with
two different VCAs in the same synth.
I've sold it some years ago, unfortunately.

> > BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
> > and they have very different transfer courves when overdriven.
> > (1-transistor version is only clipping one side of the signal)
> 
> 
	>as in MS20 (old version with korg vcf chip uses 1,and ota version
vcf
	>uses 2 
	>transistors in VCA). But it sounds so great to me (ota version)... 

The OTA version is one thing that's high on my list for things
to build.
I have the old version (with two Korg-35 modules) as a standalone
module (Part of JH-3 Modular), *without* the VCA, and it sounds
very similar to the MS-20 I used to own. So my guess is most
of the MS-20 overdrive sound is due to the filter, and not the VCA.
(But I have no real A / B test in that case. Sold my MS-20 before
I finished the JH-3 Module, if memory serves ...)
BTW, this standalone filter is noisy as hell, too, so in the MS-20
a "better" VCA would be overkill. The SSM2044 filter synths
from Korg are a different thing. Imagine the bass power of a Trident
MKII, if it wasn't for the noise !

JH.




From Chris.List at sc.siemens.com  Mon Jan  4 16:19:44 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 4 Jan 1999 10:19:44 -0500
Subject: Looking for joysticks...
Message-ID: <81A062BC5305D111A9D700805F06596801836C36@maildepo.sc.siemens.com>

Yikes! I dig fancy high-quality parts, but these things are ridiculous!
I've gotten several different types of cheapo joysticks - all for less
than $10. My favorite is spring-loaded with a button on the top of the
stick, but I can't remember where I got it...
Check the various electronic surplus places like - 
Jameco ( http://www.jameco.com/ )
Electronics Goldmine ( http://www.goldmine-elec.com/ )
Meci ( http://www.meci.com/ )

- CList


> -----Original Message-----
> From:	Arthur Harrison [SMTP:theremin1 at worldnet.att.net]
> Sent:	Monday, January 04, 1999 12:36 AM
> To:	DIY
> Subject:	Re: Looking for joysticks...
> 
> See Allied Electronic's on-line catalog:
> http://www.allied.avnet.com/catalog_pages/646.pdf
> (bottom left of page).
> These are Maurey joysticks, and they are costly!
> Then again, so are good discrete potentiometers,
> these days.
> 
> -Art
> 
> -----Original Message-----
> From: I Dream In 3D <idreamin3d at toad.net>
> To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
> Date: Sunday, January 03, 1999 3:34 PM
> Subject: Looking for joysticks...
> 
> 
> >
> >Where can I find those little joysticks (X-Y Controllers).  I'm
> building a
> >synth, and I want to integrate a joystick into my design, but I can't
> find
> >a supplier for these anywhere.  I don't want to rape an old PC
> joystick or
> >anything...I want to use all new parts because I am building a
> prototype to
> >be viewed by investors.  Thanks for your help...
> >
> >idreamin3d at toad.net
> >
> >



From jhusted at halcyon.com  Mon Jan  4 17:00:05 1999
From: jhusted at halcyon.com (James Husted)
Date: Mon, 04 Jan 1999 08:00:05 -0800
Subject: Looking for joysticks...
Message-ID: <3.0.32.19990104075918.007bc610@mail.halcyon.com>

ALPS makes a few joysticks. Unfortunately you'll have to buy lots to get
any. I recently did a search on the word "surplus" looking for a place to
get Joysticks (I have a project that's a cross between a 8 step sequencer
and 4 VCAs that will use 8 joysticks - I call it the Vector-Effector) and
found a place called Goldmine electronics in AZ that has surplus Alps 150K
miniature joy sticks for about $3 each!!! I'm going to buy at least 10.
I'll let you know what shape  their in. I'm also designing a module for my
Doepfer that has a DB connector for the standard Analog PC joystick (which
can be had for as little as $8) and gives out 2 CVs and 2 gates (the 2 push
buttons). That way you can have a remote joystick on a cable. 
Oscillater-
 James
At 04:22 PM 1/3/99 -0500, I Dream In 3D wrote:
>
>Where can I find those little joysticks (X-Y Controllers).  I'm building a
>synth, and I want to integrate a joystick into my design, but I can't find
>a supplier for these anywhere.  I don't want to rape an old PC joystick or
>anything...I want to use all new parts because I am building a prototype to
>be viewed by investors.  Thanks for your help...
>
>idreamin3d at toad.net
>
>
*******************************************************
* James Husted - The Ersatz Planet Graphics and Sound *
*               jhusted at halcyon.com                   *
*     http://www.halcyon.com/jhusted/welcome.htm      *
*******************************************************



From amieuss at telcel.net.ve  Mon Jan  4 17:12:56 1999
From: amieuss at telcel.net.ve (Arturo Mieussens)
Date: Mon, 4 Jan 1999 12:12:56 -0400
Subject: OT:  Roland Space Echo Schematic
Message-ID: <19990104161746.AAA22188@mail01.t-net.net.ve@arturomi>

Hi folks.

I have a damaged Roland Space Echo wich I would like to repair. Does
anybody know where can I get a schematic for it?, Parts?.

Thanks in advance
Arturo
amieuss at telcel.net.ve



From dmf at lotek.org  Mon Jan  4 20:22:57 1999
From: dmf at lotek.org (dmf)
Date: Mon, 04 Jan 1999 14:22:57 -0500
Subject: FS/T Stuff...
In-Reply-To: <n1297781995.93454@smtp.directmedia.com>
Message-ID: <3.0.6.32.19990104142257.007ef100@lotek.org>

Korg DSM-1 sampler, great condition $400 or Trade
Roland s330 sampler, good condition $225 or Trade

Looking for the these in trade:

korg prophecy 
korg k3m
ms404
yamaha tg77
sci Tom
other rack synths make me an offer
thanx alot for your time, happy new year...



David




From cyborg0 at GlobalEyes.net  Mon Jan  4 22:15:00 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Mon, 04 Jan 1999 15:15:00 -0600
Subject: 3904/3906 tranny specs
Message-ID: <36912F54.9C48C213@globaleyes.net>

Just wondering if it is possible to overdrive a transistor circuit to
the point that it burns up the transistor.
The synth uses 3904/3906s...
I am not exceeding Vc of the circuit..
Is there max Vbe? 
Since I am using the transistors as switches, I wouldnt think Vbe=Vc as
being a problem.

let me know..
Rob



From urekar.m at EUnet.yu  Mon Jan  4 23:04:06 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Mon, 04 Jan 1999 23:04:06 +0100
Subject: AW: CA3046 exponential converter
References: <19990104001725.24894.qmail@nuernberg2.pop.metronet.de> <3690AB88.4762@eunet.yu> <369199B0.4C63@swipnet.se>
Message-ID: <36913AD6.6F45@eunet.yu>

> 
> What would the use for tempco transistors in the Rouge be if it has a
> heater (oven)???
> None to my mind!!

Right.So that one acts as some sort of sensing diode(?) in opamps
feedback
providing 0.6v for exp pair?Not much a heater with 2M resistor
in collector.There's rogue schematic at synth diy schematic archive.


marjan



From djblue at asu.edu  Mon Jan  4 23:11:19 1999
From: djblue at asu.edu (Reverend bluE)
Date: Mon, 04 Jan 1999 15:11:19 -0700 (MST)
Subject: voltage reg. Question
Message-ID: <Pine.GSO.3.96.990104145913.7175L-100000@general1.asu.edu>


what signs does a blown voltage regulator exhibit?  (besides no output
voltage).

I have one that gets really really hot really fast, and there is no output
voltage...  

and what causes this?  I installed it and tested it, I got the desired
voltage, then after I hooked up my LED's the one didn't come on, and now that
voltage reg is the one that gets really hot, while the other side (the
negative side) is. I'm using the big regulators that have a hole in the mfor
attaching a heat sink. (can't remember the part numbers)

again, much thanks.

VCO1 is done (mounted on a piece of cardboard for now) power supply is done
(except for the blown voltage reg), and I have my power cabling set-up and
made one cable (for the VCO).  gonna test it as soon as I put in the new
regulator (but I have to go buy one first)
-ben in Phoenix




From pab210 at is8.nyu.edu  Mon Jan  4 23:26:00 1999
From: pab210 at is8.nyu.edu (Plinio Andres Barraza)
Date: Mon, 4 Jan 1999 17:26:00 -0500 (EST)
Subject: quick question
Message-ID: <Pine.OSF.3.95.990104165956.26825A-100000@is8.nyu.edu>


Hi all

  Can anyone refer me to where I can find info on matching transistors?
I know I need to match impedances to make my circuits more efficient, but
when matching two transistors that work together (like in a current
mirror for example), am I looking for them to have the same gain?
  Also, I now can borrow a tester which tells me what the gain of a
transistor is, but what can I do to test transistors the low budget way,
when I don't have access to such test equipment.



For those that are curious, this is what i am planning:  

(keep in mind that I am very ignorant about electronics)

I want to make an powerful amplifyer, possibly followed by a step up
transformer.  The purpose of the device is to use this high voltage signal 
along with coils to drive physical objects as well as old monitor cathode
raytubes.  Could be an interesting module, (.. I imagine inducing signal
into a cymbal or sequencing onto acoustic [percussion or string]
instruments...or even playing with the resonant frequencies of real
objects...)

I promise I will not electrocute myself with the +/- 25k volts
running to the anode of some of these CRT's.

any comments welcome private or public

Plinio




From Jim at base.demon.co.uk  Tue Jan  5 00:24:47 1999
From: Jim at base.demon.co.uk (James Shearer)
Date: Mon, 4 Jan 1999 23:24:47 +0000
Subject: voltage reg. Question
In-Reply-To: <Pine.GSO.3.96.990104145913.7175L-100000@general1.asu.edu>
References: <Pine.GSO.3.96.990104145913.7175L-100000@general1.asu.edu>
Message-ID: <iwufHAA$2Uk2EwGu@base.demon.co.uk>

Hi,
   Have you got a current-limiting resistor in series with the LED?
               _________
               |       |
Vunreg --------| Reg   |---------| +Vreg
               |_______|         |
                                |-|
                                | | Rlim
                                |_|
                                 |
                                 |
                                _|_
                                \ / LED
                                ---
                                 |
_________________________________| 0v

Sorry if I'm teaching granny to suck eggs..:)

Jim

In message <Pine.GSO.3.96.990104145913.7175L-100000 at general1.asu.edu>,
Reverend bluE <djblue at asu.edu> writes
>
>what signs does a blown voltage regulator exhibit?  (besides no output
>voltage).
>
>I have one that gets really really hot really fast, and there is no output
>voltage...  
>
>and what causes this?  I installed it and tested it, I got the desired
>voltage, then after I hooked up my LED's the one didn't come on, and now that
>voltage reg is the one that gets really hot, while the other side (the
>negative side) is. I'm using the big regulators that have a hole in the mfor
>attaching a heat sink. (can't remember the part numbers)
>
>again, much thanks.
>
>VCO1 is done (mounted on a piece of cardboard for now) power supply is done
>(except for the blown voltage reg), and I have my power cabling set-up and
>made one cable (for the VCO).  gonna test it as soon as I put in the new
>regulator (but I have to go buy one first)
>-ben in Phoenix
>

-- 
James Shearer



From ben at stuyts.nl  Tue Jan  5 00:57:38 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue,  5 Jan 99 00:57:38 +0100
Subject: Digital DIY synths?
Message-ID: <199901042357.AAA07241@daneel.stuyts.nl>

Hello all,

I've been on this list for a few weeks now, and I'm enjoying a lot of your  
messages. However, the focus is purely on analog DIY synths. Are digital  
synths considered heretical here? You see, one of the main disadvantages I see  
with the pure analog way of doing things is that it is hard to reproduce the  
sound or performance afterwards. (I used to have a Teisco 110F in the early  
eighties, so I know.) You could go with digital pot's from e.g. Dallas and run  
the whole thing through midi I guess.

I'm asking because I just got this DSP demo board from Analog Devices, with  
an ADSP2181 DSP, stereo A/D and D/A, and rs232 port. It seems to me it would  
be fun writing software emulating an analog synth. (Like the current crop of  
analog modeling synths, the Yamaha An1x, Access Virus, Clavia and Waldorf  
stuff, etc.)

Anybody with experience with this?

With kind regards, and I hope I did not offend anyone... B-)
Ben



From a-davidh at microsoft.com  Tue Jan  5 01:00:59 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Mon, 4 Jan 1999 16:00:59 -0800 
Subject: voltage reg. Question
Message-ID: <C35556591D34D111BB5600805F1961B90BBEAF1F@RED-MSG-47>

Sounds like an Arp Odyssey that I fixed a couple years ago.

There was a shorted tantalum cap on the main board and it caused the power
supply to show the same symptoms you are seeing.

Try disconnecting the supply and see what happens then.  Use a multi-meter
to check the DC resistance across the various circuit boards - you are
looking for a dead short.  A couple ohms is fine but dead short is a dead
give-away.


My technique for isolating the bad cap was quick and dirty but effective - I
used an Xacto knife to cut the power traces until there was no short across
the power in.  Once I had the section of the circuit isolated, I started
unsoldering one leg of each capacitor I found, checking and resoldering it
until I found the bad one.

I then used a short length of solid wire to bridge the cut power traces.

This technique is not recommended because you are cutting the pc board and
destroying any "vintaj" value. The unit in question was pretty well trashed
cosmetically and belonged to a friend who needed it fixed for a show that
day.

Good luck!

-----Original Message-----
From: Reverend bluE [mailto:djblue at asu.edu]
Sent: Monday, January 04, 1999 2:11 PM
To: DIY
Subject: voltage reg. Question



what signs does a blown voltage regulator exhibit?  (besides no output
voltage).

I have one that gets really really hot really fast, and there is no output
voltage...  

and what causes this?  I installed it and tested it, I got the desired
voltage, then after I hooked up my LED's the one didn't come on, and now
that
voltage reg is the one that gets really hot, while the other side (the
negative side) is. I'm using the big regulators that have a hole in the mfor
attaching a heat sink. (can't remember the part numbers)

again, much thanks.

VCO1 is done (mounted on a piece of cardboard for now) power supply is done
(except for the blown voltage reg), and I have my power cabling set-up and
made one cable (for the VCO).  gonna test it as soon as I put in the new
regulator (but I have to go buy one first)
-ben in Phoenix



From uhb17 at rzserv2.fh-lueneburg.de  Tue Jan  5 01:41:35 1999
From: uhb17 at rzserv2.fh-lueneburg.de (Heiko Bajus)
Date: Tue, 05 Jan 1999 01:41:35 +0100
Subject: How to make enclosures! (was: aluminum plates and profiles)
Message-ID: <3.0.1.32.19990105014135.0082e320@rzserv2.fh-lueneburg.de>

Hi all,
this is late but perhaps interesting:

Sorry for beeing late about this topic:
For my ASM1 and Fatman I went to an iron trade store and bought a plate of
aluminum (2mm thick 1000x2000mm large, cost 130 DM=80$) and an L-profile
(2mm, 20x20x6000mm, 35 DM=20$).
The parts for the enclosure were cut on a benchpress by a local metal
working company for 15 DM!  That took half an hour. You should find such a
company in any larger town. I have 2/3 of the plate left over for other
projects that shuol last for the next three years! I can't imagine to make
enclosures cheaper.

Heiko




From uzs159 at uni-bonn.de  Tue Jan  5 01:54:30 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Tue, 05 Jan 1999 01:54:30 +0100
Subject: 3904/3906 tranny specs
In-Reply-To: <36912F54.9C48C213@globaleyes.net>
Message-ID: <3.0.5.32.19990105015430.008c9a80@ibm.rhrz.uni-bonn.de>

At 15:15 04.01.99 -0600, you wrote:
>Just wondering if it is possible to overdrive a transistor circuit to
>the point that it burns up the transistor.
>The synth uses 3904/3906s...
>I am not exceeding Vc of the circuit..
>Is there max Vbe?

Not exactly but base current raises exponentially with Vbe. I think it is 
possible to burn trannies by exceeding their base current if theres no
emmiter resistor, or base resistor.

Btw. For what purpose do you want to burn them ;-)

>Since I am using the transistors as switches, I wouldnt think Vbe=Vc as
>being a problem.

Actually in a switch application Vbe might exeed Vc which is about 0.1-0.2V
for the 
switch fully on.

Bye
 Rene


             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From harv23 at leland.Stanford.EDU  Tue Jan  5 02:47:18 1999
From: harv23 at leland.Stanford.EDU (Harvey Devoe Thornburg)
Date: Mon, 4 Jan 1999 17:47:18 -0800 (PST)
Subject: Digital DIY synths?
In-Reply-To: <199901042357.AAA07241@daneel.stuyts.nl> from "Ben Stuyts" at Jan 5, 99 00:57:38 am
Message-ID: <199901050147.RAA28946@amy7.Stanford.EDU>

> 
> Hello all,
> 
> I've been on this list for a few weeks now, and I'm enjoying a lot of your  
> messages. However, the focus is purely on analog DIY synths. Are digital  
> synths considered heretical here? You see, one of the main disadvantages
> I see  
> with the pure analog way of doing things is that it is hard to reproduce
> the  
> sound or performance afterwards. (I used to have a Teisco 110F in the early  
> eighties, so I know.) 

I think this has more to do with the interface (knobs) than the 
quality of components.  It is definitely possible to get repeatable 
sounds out of analog synths with a certain level of design.
VCO's with adequate temperature compensation (such as those used 
in Serge equipment) simply do not drift: you can run a complex 
FM patch for days and it will sound very much the same. Although
with a very large number of interconnected systems we approach
100% likelihood that something will go wrong...  With pots,
it is very difficult to set precise values.  You have to do everything
by ear rather than rely on mathematical relationships.  Also,
digital systems permit a reuse of components (no repetitive design).

There is little discussion about "digital DIY" because most 
people on the list seem to work primarily (perhaps not exclusively)
with analog.  I don't think there's an explicit attitude against
it, it just doesn't come up that often.  Personally,
I value more DSP discussion.

You might also be interested in the music-dsp list.  About 70% of
the posts are about audio DSP stuff, the other 30% discuss a 
certain member who likes to flood the list with manifestoes and
machine gibberish (I personally find him/her entertaining, and he/she
has developed some interesting software).  find out more at
http://shoko.calarts.edu/~glmrboy/musicdsp/music-dsp.html

so welcome, and I look forward to your posts!
--Harvey






From zzynt at swipnet.se  Tue Jan  5 05:15:55 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 20:15:55 -0800
Subject: AW: AW: VCO-1C
References: <1BF5E20E0C4DD111BBAB00805FE2D582011513C0@nbgm336a.nbgm.siemens.de>
Message-ID: <369191FB.54F3@swipnet.se>

Haible Juergen wrote:
> 
>         >Actually i dont find the MS20 noisy it is in fact rater silent,
>         >but on the other hand the Monopoly is wery noisy, i have owned
> both.
> 
> Was this an early MS-20 or a later model ?

Later one!

> I only played early ones (with Korg-35 ICs), and they were
> quite noisy (more than my Mono/Poly). I never played
> a later MS-20, but they have LM13600-based filters and
> a deemphasis (470us, 6dB) after the VCA (where is the
> preemphase counterpart ??), and they are said to be
> more quiet.

> 
>         >The one transistor VCA is  used in the JX3P and JX8P and they are
>         >not particular noisy i think!
> 
> Never seen these schemos. Are they anywhere on the web?

Well no, until now!!
I have scanned in the JX3 and 8P audio parts 
with my "wobbling" hand scanner at:
http://home8.swipnet.se/~w-88660/schpcb.htm

Have a look on the resonance feedback part of the JX3P!!

BJ



From zzynt at swipnet.se  Tue Jan  5 05:32:34 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 20:32:34 -0800
Subject: AW: AW: VCO-1C
References: <1BF5E20E0C4DD111BBAB00805FE2D582011514B5@nbgm336a.nbgm.siemens.de>
Message-ID: <369195E2.1E4B@swipnet.se>

Haible Juergen wrote:
> 
>         >Polysix also uses such VCA (with two transistors) and it sounds
> rather
>         >noisy to me (even with effect section turned off),but IMO it's not
>         >so bad in final mix.
> 
> Same for the Mono/Poly. It's grat for all kind of Lead sounds,
> and you won't notice the noise. But for low bass sounds, or
> dark pad sounds, a good VCA makes a great difference.
> Not just in theory - I made a direct A / B comparison with
> two different VCAs in the same synth.
> I've sold it some years ago, unfortunately.
> 
> > > BTW, there's a 1-transistor and a 2-transistor version of this Korg-VCA,
> > > and they have very different transfer courves when overdriven.
> > > (1-transistor version is only clipping one side of the signal)
> >
> >
>         >as in MS20 (old version with korg vcf chip uses 1,and ota version
> vcf
>         >uses 2
>         >transistors in VCA). But it sounds so great to me (ota version)...
> 
> The OTA version is one thing that's high on my list for things
> to build.
> I have the old version (with two Korg-35 modules) as a standalone
> module (Part of JH-3 Modular), *without* the VCA, and it sounds
> very similar to the MS-20 I used to own. So my guess is most
> of the MS-20 overdrive sound is due to the filter, and not the VCA.
> (But I have no real A / B test in that case. Sold my MS-20 before
> I finished the JH-3 Module, if memory serves ...)
> BTW, this standalone filter is noisy as hell, too, so in the MS-20
> a "better" VCA would be overkill. The SSM2044 filter synths
> from Korg are a different thing. Imagine the bass power of a Trident
> MKII, if it wasn't for the noise !
> 
> JH.

I heard a story once, it was a interwiew with the Korg designer 
who had designed all those old Korg machines, and his personal favorite 
was the Monopolly!
Personally i dont like the way the ADRS behaves in the MP!

Well, i still dont think that the JX3P or the MS20 (later) are noisy.

BJ
(in the land of noise!)



From dmf at lotek.org  Tue Jan  5 05:33:34 1999
From: dmf at lotek.org (dmf)
Date: Mon, 04 Jan 1999 23:33:34 -0500
Subject: FS/T Stuff... More
In-Reply-To: <3.0.6.32.19990104142257.007ef100@lotek.org>
References: <n1297781995.93454@smtp.directmedia.com>
Message-ID: <3.0.6.32.19990104233334.007f4330@lotek.org>

Korg DSM-1 sampler, great condition $400 or Trade
Roland s330 sampler, good condition $225 or Trade
Motu micro express 4ins/6outs + smpte *mint* in box $200 or Trade
JLCooper midi patchbay 8x8 great condition $100 or Trade (used it in
conjuction with the motu will do both for $250)

Looking for the these in trade:

korg prophecy 
korg k3m
ms404
yamaha tg77
sci Tom
mackie 1402vlz
other rack synths make me an offer
thanx alot for your time, happy new year...



David




From zzynt at swipnet.se  Tue Jan  5 05:38:53 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 20:38:53 -0800
Subject: AW: AW: VCO-1C
References: <1BF5E20E0C4DD111BBAB00805FE2D582011514B5@nbgm336a.nbgm.siemens.de>
Message-ID: <3691975D.2900@swipnet.se>

Haible Juergen wrote:
 
> Same for the Mono/Poly. It's grat for all kind of Lead sounds,
> and you won't notice the noise. But for low bass sounds, or
> dark pad sounds, a good VCA makes a great difference.
> Not just in theory - I made a direct A / B comparison with
> two different VCAs in the same synth.

Between wich VCA designs?

> The OTA version is one thing that's high on my list for things
> to build.
> I have the old version (with two Korg-35 modules) as a standalone
> module (Part of JH-3 Modular), *without* the VCA, and it sounds
> very similar to the MS-20 I used to own. So my guess is most
> of the MS-20 overdrive sound is due to the filter, and not the VCA.
> (But I have no real A / B test in that case. Sold my MS-20 before
> I finished the JH-3 Module, if memory serves ...)
> BTW, this standalone filter is noisy as hell, too, so in the MS-20
> a "better" VCA would be overkill. 

I think thats the reason Korg made a low noise OTA filter instead! 

>The SSM2044 filter synths
> from Korg are a different thing. Imagine the bass power of a Trident
> MKII, if it wasn't for the noise !

Did the trident use the same VCA design as the MS20?

BJ



From theremin1 at worldnet.att.net  Tue Jan  5 05:46:29 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Mon, 4 Jan 1999 20:46:29 -0800
Subject: Minimum Parts VCO was VCO-1C
Message-ID: <000e01be3866$5ce6c5c0$147e4e0c@hpcustomer>

Re:  http://www.mindspring.com/~vco/misc/pics/vco6a_sd.gif
I'd be somewhat concerned about the tempco of 13600's trasconductance.

-Art

-----Original Message-----
From: tomg <vco at mindspring.com>
To: jhaible <jhaible at metronet.de>; synth-diy at mailhost.bpa.nl
<synth-diy at mailhost.bpa.nl>
Date: Monday, January 04, 1999 12:41 AM
Subject: Minimum Parts VCO was VCO-1C


>
>
>I never posted this because I didn't finish testing
>it completely. If you don't look at the waveforms
>it sounds like a saw but they look like a bad tri.
>
>If you get rid of the exp-conv's it leaves 1/2 a
>13600 one cap 2 diodes and 4 resistors. Reduces
>the cost to about $.70 per key. May be just what
>you want...might not be though.
>
>
>http://www.mindspring.com/~vco/misc/pics/vco6a_sd.gif
>
>-tg
>
>
>




From zzynt at swipnet.se  Tue Jan  5 05:48:48 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 04 Jan 1999 20:48:48 -0800
Subject: AW: CA3046 exponential converter
References: <19990104001725.24894.qmail@nuernberg2.pop.metronet.de> <3690AB88.4762@eunet.yu>
Message-ID: <369199B0.4C63@swipnet.se>

Marjan wrote:

> Rogue uses 1 tranny heather method,2 for vco expos,1 for vcf,1 not
> used,2 100R
> tempcos for vcos
> Micro uses 2 for standard expo for vco, 1 for heater,1 for vcf and 1 for
> current source,temp trim for 56'C adjust
> Multi has 2 arrays for vcos, each: 2 for expo conv, 1 heater+temp trim,2
> unused
> Prodigy uses 2 for expo,1 unused,2 for sensor diode and heater (oven)
> and temp
> trim (also in Doepfer modular discrete vco)
> 
> marjan

That means that none are using 3 TR's for expo, 1 TR for heater, and 1
TR as sensor TR?
As i have done in the tripple expo conv shemo at:
http://home8.swipnet.se/~w-88660/schpcb.htm

Does any one have any coments on the design please?

What would the use for tempco transistors in the Rouge be if it has a
heater (oven)???
None to my mind!!

BJ



From cyborg0 at GlobalEyes.net  Tue Jan  5 06:12:02 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Mon, 04 Jan 1999 23:12:02 -0600
Subject: 3904/3906 tranny specs
References: <3.0.5.32.19990105015430.008c9a80@ibm.rhrz.uni-bonn.de>
Message-ID: <36919F22.CA572B38@globaleyes.net>

Rene Schmitz wrote:
> 
> At 15:15 04.01.99 -0600, you wrote:
> >Just wondering if it is possible to overdrive a transistor circuit to
> >the point that it burns up the transistor.
> >The synth uses 3904/3906s...
> >I am not exceeding Vc of the circuit..
> >Is there max Vbe?
> 
> Not exactly but base current raises exponentially with Vbe. I think it is
> possible to burn trannies by exceeding their base current if theres no
> emmiter resistor, or base resistor.
> 
> Btw. For what purpose do you want to burn them ;-)

Ahh, i was bored and I figured "Hey, I got a lot of these laying around,
lets make some  fire!" I watched that old 60's video "Fire" by that guy
and his mad world..' i am the god of hell and fire and I bring you:
3904s!! :)
sung amidst a breadboard full of burning 3904s whilst you pretend to
lick the flames..

No, honestly, I have a circuit in one of my synths that takes 5v and
converts it to 12v using 3904s trannies. BUT, i want to manipulate the
data with 4000 series cmos chips.. I want to run these off of the 12v
supply cuz they have better noise rejection @12v (and since there is
very critical circuits on the 5v supply, like the d/a converters that go
to the oscillator CVs) so I cant use the 5v supply.
> 
> >Since I am using the transistors as switches, I wouldnt think Vbe=Vc as
> >being a problem.
> 
> Actually in a switch application Vbe might exeed Vc which is about 0.1-0.2V
> for the
> switch fully on.
> 

Oh, ok.. then, if I add a series resistance to the 12v output of my
cmos, then that should limit the current enough to not cause a problem.. 
Its the voltage isnt the problem, the current is..
heh, I should have paid more attention in my discrete semiconductors
class.. :)

Rob



From vco at mindspring.com  Tue Jan  5 06:46:42 1999
From: vco at mindspring.com (tomg)
Date: Tue, 05 Jan 1999 00:46:42 -0500
Subject: Mad Mouse PCBs for Sale
Message-ID: <yam7674.2142.121023360@mail.mindspring.com>

By popular demand. The Mad Mouse PCB will soon be available.
The target date for delivery to me is the 18th of January. All 
orders received before then should be shipped by Friday the 
22nd. I have placed the order for 20 boards. These be be sold 
on a first come first serve basis. There is no limit you may buy
as many as you want. I'll have more made if I run out.

The first 20 orders will receive a *FREE* peel and press panel 
layout sticker.

The boards cost $25.00 each, includes S&H.

Look here for more info.

http://www.mindspring.com/~vco/madm/mm_order.html

-tg





From beszedes at cc.u-szeged.hu  Tue Jan  5 08:55:15 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Tue, 05 Jan 1999 08:55:15 +0100
Subject: quick question
References: <Pine.OSF.3.95.990104165956.26825A-100000@is8.nyu.edu>
Message-ID: <3691C563.5B745F57@cc.u-szeged.hu>

Hi!

I don't remember from where I have downloaded this file, but maybe it'll
help...

Regards, Arpad.


Plinio Andres Barraza wrote:
> 
> Hi all
> 
>   Can anyone refer me to where I can find info on matching transistors?
> I know I need to match impedances to make my circuits more efficient, but
> when matching two transistors that work together (like in a current
> mirror for example), am I looking for them to have the same gain?
>   Also, I now can borrow a tester which tells me what the gain of a
> transistor is, but what can I do to test transistors the low budget way,
> when I don't have access to such test equipment.
> 
> For those that are curious, this is what i am planning:
> 
> (keep in mind that I am very ignorant about electronics)
> 
> I want to make an powerful amplifyer, possibly followed by a step up
> transformer.  The purpose of the device is to use this high voltage signal
> along with coils to drive physical objects as well as old monitor cathode
> raytubes.  Could be an interesting module, (.. I imagine inducing signal
> into a cymbal or sequencing onto acoustic [percussion or string]
> instruments...or even playing with the resonant frequencies of real
> objects...)
> 
> I promise I will not electrocute myself with the +/- 25k volts
> running to the anode of some of these CRT's.
> 
> any comments welcome private or public
> 
> Plinio

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************
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From jorgen.bergfors at idg.se  Tue Jan  5 09:25:55 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 5 Jan 1999 9:25:55 +0100
Subject: Digital DIY synths?
Message-ID: <TFSACUTG@idg.se>

The main reason analog is more popular among DIY types is that it is much more suited to DIY. You can build almost any circuit with standard parts and if it doesn't work, you can follow the signal with an oscilloscope to diagnose it. With digital, almost everything is controlled by software. That means it is impossible to change unless you have access to the source code. Also digital synths normally use special-purpose ICs, which can't be bought from an electronics supplier. You also need special equipment, like PROM-burners and such, to do digital. And with the low prices of mass-produced digital synths, there wouldn't be any cost benefit to build them yourself either.

/Jorgen




From magnus at analogue.org  Tue Jan  5 10:47:51 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 05 Jan 1999 10:47:51 +0100
Subject: Digital DIY synths?
In-Reply-To: Your message of "Tue, 5 Jan 1999 9:25:55 +0100"
References: <TFSACUTG@idg.se>
Message-ID: <199901050947.KAA15300@mail2.it.kth.se>

>>>>> "jb" == jorgen bergfors <jorgen.bergfors at idg.se> writes:

 jb> The main reason analog is more popular among DIY types is that it
 jb> is much more suited to DIY. You can build almost any circuit with
 jb> standard parts and if it doesn't work, you can follow the signal
 jb> with an oscilloscope to diagnose it. With digital, almost
 jb> everything is controlled by software. That means it is impossible
 jb> to change unless you have access to the source code. Also digital
 jb> synths normally use special-purpose ICs, which can't be bought
 jb> from an electronics supplier. You also need special equipment,
 jb> like PROM-burners and such, to do digital. And with the low
 jb> prices of mass-produced digital synths, there wouldn't be any
 jb> cost benefit to build them yourself either. 

I agree, also...

Not only are many things hidded, but things is a bit more obscure than
you might find in analog cursuits. The frequency wrapping, the yeat
harder math, the impact of low resolution/quantization etc. all add
up.

Another thing is the availablility of free tools.

Yeat further reasons is that adapting it into the environment of
things that one already has is greater. With analogs you maybe just
need to adjust the signal levels or so, for control signals it is the
linear/expo limit that is among the more expensive ones that one
usually see, but it is still at a fairly low level after all.

Also, when you actually build something the complexity grows on you,
you quickly run into packages with many signals, more and more surface
mounting, timing, high frequency problems etc.

Mastering each of these fields enought certainly filters many people
out.

Never the less, it is fun to play with the thoughts.

Lately I have playing with the idea of using PICs for simpler tasks,
they are not the strongest DSPs, MCUs or CPUs you may find, but they
fit the smaller range. There are free tools available and a lot of
material online. They come in fairly small packages at a decent price.
The assembler has it sides, but you can do stuff with it. They may not
glue up with A/Ds and D/As as obviously simple as a larger DSP would,
but there are hints on how to do this aswell. It seems fairly
promessing.

Cheers,
Magnus





From per.mattsson at mkv.mh.se  Tue Jan  5 10:56:41 1999
From: per.mattsson at mkv.mh.se (Per Mattsson)
Date: Tue, 05 Jan 1999 10:56:41 +0100
Subject: TI-76477
Message-ID: <fc.000f49240037ff1b000f49240037ff1b.37ff1e@mkv.mh.se>

There was some talk about the Texas 76477 sound-chip. I have scanned a
good article on a mini-"synth" from Popular Electronics May 1980.
<http://www.mkv.mh.se/staff/per/76477/>
 I cannot promise that these scans will be here forever so if you  are
interested - get them!

//Per - back in 1980 this was also my first building project ever.
Needless to say it failed completely :) The 76477 survived though, I still
have thoughts on making a module based on the schematics in the article.




From jorgen.bergfors at idg.se  Tue Jan  5 10:59:12 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 5 Jan 1999 10:59:12 +0100
Subject: VC Phaser using the LM13600
Message-ID: <TFSAFZNZ@idg.se>

Hi all.
I designed and built a test circuit inspired by the EH Small Stone. Instead of the CA3094, I wanted to use the LM13600. The test circuit consists of an exponential voltage to current converter and two all-pass stages. In an actual phaser more than two stages of course would be used. The Small Stone has four, some other phasers have six. Phase shift is around zero at 0V CV and increases with increasing control voltage.

The following was measured om my test circuit:

Frequency Phase shift (0 to 10V CV)
18 Hz 45 - 350 degrees
37 Hz 30 - 340 degrees
75 Hz 20 - 330 degrees
150 Hz 15 - 300 degrees
300 Hz 10 - 250 degrees
600 Hz 0 - 250 degrees
1200 Hz 0 - 110 degrees
2400 Hz 0 - 55 degrees

As can be seen, there is some phase shift at lower frequencies even when the control voltage is 0 volts. The frequency response falls to -3 dB at 24 Hz. This is the worst case, at 5V CV. At 10V CV it seems to be flat down to DC. At 0V CV it goes down to 18 Hz. There is no HF damping (below 20 kHz).
Noise and distortion seems to be low. I haven't measured them, but they aren't noticable on the scope or at listening tests.
Note that phase shift is higher att low frequencies. Is this common to all phasers or are there phasers that are the other way round (higher phase shifts at high frequencies)?

/Jorgen





From alexandr at irit.fr  Tue Jan  5 11:27:31 1999
From: alexandr at irit.fr (Karl ALEXANDRE)
Date: Tue, 05 Jan 1999 11:27:31 +0100
Subject: BA6110 and pcb orders
References: <000501be38db$3a782c20$cb06883e@default>
Message-ID: <3691E913.516CF8EE@irit.fr>

Tony Allgood wrote:
> 
> Hi All,
> 
> Due to public request I may have to try out the above part as a sub for
> the 662. Has anyone tried it yet?

	I just get mine, not cheap. I'll try in a few days because 
	i'm busy on an other thing. 
	
	Btw, does anyone here have information on a pal programmer ?
	I want to build one, not to buy one.
	Not very synth related, excuse me ...



From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 11:38:01 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 11:38:01 +0100 
Subject: AW: AW: AW: VCO-1C
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820115166F@nbgm336a.nbgm.siemens.de>

	>>         >The one transistor VCA is  used in the JX3P and JX8P and
they are
	>>         >not particular noisy i think!
	>> 
	>> Never seen these schemos. Are they anywhere on the web?
	>
	>Well no, until now!!
	>I have scanned in the JX3 and 8P audio parts 
	>with my "wobbling" hand scanner at:
> http://home8.swipnet.se/~w-88660/schpcb.htm
	>
	>Have a look on the resonance feedback part of the JX3P!!

Thanks for scanning the stuff. The resonance feedback
VCA is weird indeed. Now who knows a textbook
for the theory of *that* ?? I'd try tro look at these transistors
as reverse conducting, for a start, i. e. emitters and collectors
swapped (which results in a very low beta, but has other
advantages) - but it's just a guess, and doesn't explain
everything ... if anything ...

JH.



From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 11:46:38 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 11:46:38 +0100 
Subject: AW: AW: AW: VCO-1C
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820115167D@nbgm336a.nbgm.siemens.de>

	> Personally i dont like the way the ADRS behaves in the MP!

What's wrong with it ? 

	> Well, i still dont think that the JX3P or the MS20 (later) are
noisy.

With a low SNR device, you always have a tradeoff between
noisy and distorted. Now distortion isn't such a bad thing
per se in the VCA of a single synth voice. The JX3P is
generally described as "harsh" sounding (don't beat me !),
so maybe they are more on the overdrive side ?
I really don't know - just a guess.

JH.




From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 11:47:53 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 11:47:53 +0100 
Subject: AW: BA6110 and pcb orders
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151682@nbgm336a.nbgm.siemens.de>

I've bought a couple, but haven't tried them yet.

JH.




From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 12:01:48 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 12:01:48 +0100 
Subject: AW: AW: CA3046 exponential converter
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820115168D@nbgm336a.nbgm.siemens.de>

	>That means that none are using 3 TR's for expo, 1 TR for heater,
and 1
	>TR as sensor TR?
	>As i have done in the tripple expo conv shemo at:
> http://home8.swipnet.se/~w-88660/schpcb.htm
> 
	>Does any one have any coments on the design please?

Looks pretty straight forward. I can't tell how stable the
temp regulation is - you'll have to build it to find out.

I was puzzled because I was looking for the "reference"
transistor (which would make an expo pair with each
of the 3 expo transistors) in vain. So you just use a single
transistor for each expo converter, and rely on the constant
temperature completely. I have seen this once, probably in 
the EML synths (from memory), using two halves of a 726
for two expo converters. I can't tell how well this works
(what's the general experience with the stability of EML
stuff ?), but most manufacturers didn't trust the temp regulation
to the extreme, and used the 1st order compensation of a 
transistor pair nevertheless.
I can see some reason to use a 726 economically, but there's
no real reason to go without a reference transistor in *your*
circuit. You could build a triple expo converter from 4 transistors
(like I did a quad from 5 in the 2040 style VCF), and still use
the 4th transistor as temperature sensor.
As I said; i can't tell how good the performance of your circuit
is, but I wanted to say that there might be a way to improove it
without much additional effort.

JH.




From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 12:07:53 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 12:07:53 +0100 
Subject: AW: AW: AW: VCO-1C
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151699@nbgm336a.nbgm.siemens.de>

	>Haible Juergen wrote:
	> 
	>> Same for the Mono/Poly. It's grat for all kind of Lead sounds,
	>> and you won't notice the noise. But for low bass sounds, or
	>> dark pad sounds, a good VCA makes a great difference.
	>> Not just in theory - I made a direct A / B comparison with
	>> two different VCAs in the same synth.
	>
	>Between wich VCA designs?

The original one, and my modification (two halves of a
SSM2020 in parallel).

	>> BTW, this standalone filter is noisy as hell, too, so in the
MS-20
	>> a "better" VCA would be overkill. 
	>
	>I think thats the reason Korg made a low noise OTA filter instead! 

Maybe so. Or they just ran out of Korg-35 modules. And while
redesigning it, they took care of the noise as well. The 
"deemphasis" trick would have worked on the Korg-35 filters
as well, and that alone brings 6dB improovement in the mid
and upper range.

	> Did the trident use the same VCA design as the MS20?

I think so. Can anybody confirm ? (Don't have schemos here)

JH.




From fa_diy at fa.camelot.de  Tue Jan  5 13:35:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 05 Jan 1999 14:35:00 +0200
Subject: AW: VCO-1C
In-Reply-To: <19990103165927.18861.qmail@nuernberg2.pop.metronet.de>
Message-ID: <78GnXMZ$HFB@fa.camelot.de>

Hello Juergen,


>Any Korg PE-1000 and PE-2000 owners: Do these instruments really have
>individual VCOs, or are they divide-down units ? (I don't have schemos,
Long time ago (10 years?) I saw the schemos (and I hope I do not mix them up  
with the Korg PS-3xxx Polysynths), but I think they had twelve VCOs and  
octave-dividers.


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From fa_diy at fa.camelot.de  Tue Jan  5 13:50:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 05 Jan 1999 14:50:00 +0200
Subject: Filters?
In-Reply-To: <369056EF.559B@swipnet.se>
Message-ID: <78GnXXt4HFB@fa.camelot.de>

Hello BJ


>Im interested in the audio difference between those filter types!
We tried once to compare several Moog-ladders (1 Minimoog, 2 Rogue, Doepfer  
A120) and a diy-diode-ladder filter and two TR-303. We used as Standard- 
Waveform a sawtooth from an CEM-3340 sent it over an TL064-buffer to the  
filters. Filter outputsignal via TL064 buffer to scope/audio monitoring.
For measurement we only used a scope and our ears.

What we found out, was, that the differences between two devices of the same  
type (Rogue, TR303) were bigger than the difference between the different  
brands!

Especially the behavior over a wide frequency range differred a lot.


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From magnus at analogue.org  Tue Jan  5 14:02:34 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 05 Jan 1999 14:02:34 +0100
Subject: VC Phaser using the LM13600
In-Reply-To: Your message of "Tue, 5 Jan 1999 10:59:12 +0100"
References: <TFSAFZNZ@idg.se>
Message-ID: <199901051302.OAA16696@mail2.it.kth.se>

>>>>> "jb" == jorgen bergfors <jorgen.bergfors at idg.se> writes:

 jb> Hi all.
 jb> I designed and built a test circuit inspired by the EH Small Stone. 
 jb> Instead of the CA3094, I wanted to use the LM13600. The test
 jb> circuit consists of an exponential voltage to current converter
 jb> and two all-pass stages. In an actual phaser more than two stages
 jb> of course would be used. The Small Stone has four, some other
 jb> phasers have six. Phase shift is around zero at 0V CV and
 jb> increases with increasing control voltage. 

 jb> The following was measured om my test circuit:

 jb> Frequency Phase shift (0 to 10V CV)
 jb> 18 Hz 45 - 350 degrees
 jb> 37 Hz 30 - 340 degrees
 jb> 75 Hz 20 - 330 degrees
 jb> 150 Hz 15 - 300 degrees
 jb> 300 Hz 10 - 250 degrees
 jb> 600 Hz 0 - 250 degrees
 jb> 1200 Hz 0 - 110 degrees
 jb> 2400 Hz 0 - 55 degrees

 jb> As can be seen, there is some phase shift at lower frequencies
 jb> even when the control voltage is 0 volts. The frequency response
 jb> falls to -3 dB at 24 Hz. This is the worst case, at 5V CV. At 10V
 jb> CV it seems to be flat down to DC. At 0V CV it goes down to 18 Hz.
 jb> There is no HF damping (below 20 kHz). 

 jb> Noise and distortion seems to be low. I haven't measured them,
 jb> but they aren't noticable on the scope or at listening tests. 
 jb> Note that phase shift is higher att low frequencies. Is this
 jb> common to all phasers or are there phasers that are the other way
 jb> round (higher phase shifts at high frequencies)? 

Well, the phase distorsion from a single pole or zero becomes greater
the nearer you come to them. In the s-plane your above analysis would
appear as a number of test-points on the jw-axis. The classical
allpass filters in phasers (such as the EH SmallStone) are built in a
1-pole/1-zero structure, where all the poles and zeros will be real,
and thus placed on the sigma-axis (which is real). I don't recall
exactly how the zero's moved when you made the feed-forward, but they
move. Now, when you place your analysis point on 18 Hz (113 rad) you
place yourself very close to origo (and thus very close to the sigma
axis) and this will be the closest point to the poles and zeros and
thus see the greatest phase distorsion as compared to the higher
frequencies (which are inherently farther away). As you modulate you
move the poles and zero on the sigma axis, closer (or further away) to
the jw-axis, and then will the higher frequency points become closer
and thus become more affected by the preccens of each of the poles and
zeros. In the allpass filters will the phase contribution of a pole
and its corrensponding zero be additative, so whatever phase
distorsion that the single pole would contribute with, the zero will
add exactly (well, in theory) the same.

With all this in mind... yes, if you allowed for complex poles and
zeros in your allpass filter function, you could move the effect. For
a full bank of allpass you could optimize them to acheive flattness
and all of a sudden you are making a Hilbert transform approximation,
oups!

For a Phaser, what really intests you is where zeros ends up (when
including the feed forward part), since the effect when these move all
over the place is at least in my mind much of the phaser sound, not
the phase itself.

Cheers,
Magnus



From fa_diy at fa.camelot.de  Tue Jan  5 14:45:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 05 Jan 1999 15:45:00 +0200
Subject: OT:  Roland Space Echo Schematic
In-Reply-To: <19990104161746.AAA22188@mail01.t-net.net.ve@arturomi>
Message-ID: <78GnXoEKHFB@fa.camelot.de>

Hello Arturo

>I have a damaged Roland Space Echo wich I would like to repair. Does
>anybody know where can I get a schematic for it?, Parts?.
Both you should get at the regional/national roland-distributor. (I don't  
know who it is for your country, with Roland-Germany there is no problem  
getting schematics or spare parts

Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From varner at k-online.com  Tue Jan  5 15:37:53 1999
From: varner at k-online.com (Steve Varner)
Date: Tue, 05 Jan 1999 06:37:53 -0800
Subject: CA3046 exponential converter
References: <368E610E.13C89E69@k-online.com>
Message-ID: <369223C0.E2B2715B@k-online.com>

I guess not many people have built the 3046 VCO and thermostat as shown in
Klein's book. The difference between this design and the AN-299 design is
that the matching transistors and one other transistor are used in the
standard VCO way, and the last two are used for temperature sensing and
heating. There is no transistor used for the clamp. I'll try this design
and let people know how it works.

SV


--------------------------------------
Steve Varner wrote earlier:

> Barry Klein has a CA3046 exponential converter (fig.4-4, p.87) in his
> "Electronic music circuits." This is the same as the ENS-76 VCO option
> 1A found in the "Preferred Circuits Collection." These schematics show
> temperature compensation using the 2k tempco.
> Barry also has a CA3046 2-transistor thermostat circuit (Fig. 4-3, p.86)
> using the remaining transistors on the array (Q4 and Q5). It seems very
> simple. (I suppose you would then leave off the tempco resistor and
> replace it with a regular resistor.)
> Has anyone built this exact VCO setup? If it works well... godbye
> matched pairs and tempcos for me. 3046's only cost about 35 cents.
>
> (And yes, I have seen the AN-299 VCO circuit. Anyone actually built one
> of these into a VCO module?)
>
> Steve Varner
> mailto:varner at k-online.com






From martink at cix.co.uk  Tue Jan  5 16:54:00 1999
From: martink at cix.co.uk (Martin J Keefe)
Date: Tue, 5 Jan 1999 15:54 +0000 (GMT)
Subject: 3904/3906 tranny specs
In-Reply-To: <36919F22.CA572B38@globaleyes.net>
Message-ID: <memo.19990105155431.257B@martink.compulink.co.uk>

> that guy and his mad world..

The Crazy World of Arthur Brown. Still performing apparently and was 
interviewed last year for one the BBC's "Rock Family Trees" programmes.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From mirwin1 at istar.ca  Tue Jan  5 17:43:25 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Tue, 05 Jan 1999 11:43:25 -0500
Subject: VC Phaser using the LM13600
References: <TFSAFZNZ@idg.se>
Message-ID: <3692412D.DBA9027@istar.ca>

Hello,
The phase versus frequency function for a typical single RC all-pass
filter is given by

 phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter and

phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type filter.

(This is the one op amp type filter with 1 capacitor, 2 fixed R's and 1
variable R). The function looks like an "S" elongated in the horizontal
direction. The rate of phase change is greatest at the turnover
frequency. Varying R (or the control current of the OTA) does not change
the overall shape of the curve, it just varies the turnover frequency.
When the phase-shifted signal is summed with the dry signal a notch will
be produced at the turnover frequency (for 2 all-pass filters in series
giving a cumulative phase shift of 180 degrees at the turnover
frequency). Putting more  filters in series produces additional
cancellations where in each case the cumulative phase shift (at each
notch frequency) is an odd  multiple of 180 degrees (for a summing-type
output stage).




From b.layer at vikingelectronics.com  Tue Jan  5 17:55:44 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 05 Jan 1999 10:55:44 -0600
Subject: Wiggins Circlotron
Message-ID: <3.0.6.32.19990105105544.007c46d0@192.168.210.18>

Hey All,

(This is a bit obscure, but...)

Has anyone on the list (besides me) ever experimented with Circlotron
output sections for pre or power amplifiers? This is a very unusual type of
circuit, and is currently highly controversial.

For those of you that don't know, the circlotron section is a novel method
of direct-coupling a signal output (sans caps or xfmrs, which have a way of
wrecking musical signals). An unusual feature of the design is that it
requires two identical floating power supplies to function.

Anyone?


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"



From thelab at sprint.ca  Tue Jan  5 18:26:18 1999
From: thelab at sprint.ca (|||| Philip Pilgrim ||||)
Date: Tue, 05 Jan 1999 13:26:18 -0400
Subject: ARP Odyssey AR Hacked
Message-ID: <36924B3A.6965@sprint.ca>

Hi all,

I used the simple Arp AR envelope from the Odyssey in my SH-101 NovaMod
upgrade (due to it's simplicity) but was never really satisfied with it.
The main problem was that the envelope could not be re-triggered by a
new key press thus it had a portamento-ish amplitude slurring. 

A few people on this list requested that I update them if I ever figured
out how to re-trigger the env....well here it is:

I finally had a chance to hack the circuit in my typical crude but
usually functional fashion and found that by adding a resistor and
transistor, the circuit could now accept a re-trigger signal. I never
checked to see if the odyssey had an available trigger signal however
the SH-101 has a hi to low transition trigger which I used (found at R36
on synth board btw).

The attached AR circuit (re-annotated from the Odyssey values) has the
two new parts R7 and Q3 added. It is obvious that the negative
trigger-in switches the transistor Q3 and drains the charge on the cap
C2 thus resetting the output to 0V.

For positive pulse triggers simply use a NPN (2N5172).

Finally the attack and decay times can be increased by increasing the
value of C2. I experimented last evening and found 4.7uf very useful.

All of these improvements should be easy to do on an odyssey from the
solder side of the board :)

enjoy!
Philip

-- 
Philip Pilgrim               The Lab
5 Evan's Drive               synth mods, software development
Hammond's Plains             digital audio recording/mastering
Nova Scotia, Canada          music architecture/construction
B4B 1M8
(902) 835-7844

           Home of NovaMod, UP and Microwave tools

           web page: http://www.robotnik.com/the_lab
           email:    mailto:thelab at sprint.ca
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From dbalvage at ptdcs2.ra.intel.com  Tue Jan  5 18:40:29 1999
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Tue, 05 Jan 1999 09:40:29 -0800
Subject: Sampling and Nyquist/Antialiasing filters
Message-ID: <36924E13.31DF@ptdcs2.intel.com>

Hello all -

Is there anyone out there who has any basic guidelines on how many dB

down "aliasing" frequencies have to be so they are not a problem?

I'm retrofitting my Prophet-2000 sampler with 2 switched-cap

6-pole filters in series (12 poles, 72 dB/oct) for the antialiasing

filter. (The antialiasing filters in it now are a bit, uhh, conservative
 
to say the least) Right now they sit at:

41Khz sample rate : 16Khz corner freq.

32Khz sample rate : 12Khz corner freq.

24Khz sample rate : 9Khz  corner freq.

They are using 4 pole input filters (I think - have to check the schems)

so the slopes are a bit gradual, taking off some of the "sparkle" of

the samples because they have to have their corner frequency set low 

enough to avoid aliasing. Any suggestions???

					- Duane
-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From tsheets at saturn5.com  Tue Jan  5 18:57:30 1999
From: tsheets at saturn5.com (Troy Sheets)
Date: Tue, 5 Jan 1999 09:57:30 -0800 (PST)
Subject: Digital DIY synths?
In-Reply-To: <199901050947.KAA15300@mail2.it.kth.se> from "Magnus Danielson" at Jan 5, 99 10:47:51 am
Message-ID: <199901051757.JAA18290@atari.saturn5.com>


Plus, working on analog circuits is just more of an art.  There
are so many more variables... Simple things like how well you have
matched a transistor pair have subtle influences on the sound 
quality... how hard you drive your filter, ect.  It is these
little details that make your own analog synth a real unique
artistic tool.  Plus, I don't know... I just think analog circuits
have more "life" in them... they breathe and pulsate and you can hear
the electrons squirting through your circuits.   Digital is just more 
sterile and mathmatic.

-troy


> 
> >>>>> "jb" == jorgen bergfors <jorgen.bergfors at idg.se> writes:
> 
>  jb> The main reason analog is more popular among DIY types is that it
>  jb> is much more suited to DIY. You can build almost any circuit with
>  jb> standard parts and if it doesn't work, you can follow the signal
>  jb> with an oscilloscope to diagnose it. With digital, almost
>  jb> everything is controlled by software. That means it is impossible
>  jb> to change unless you have access to the source code. Also digital
>  jb> synths normally use special-purpose ICs, which can't be bought
>  jb> from an electronics supplier. You also need special equipment,
>  jb> like PROM-burners and such, to do digital. And with the low
>  jb> prices of mass-produced digital synths, there wouldn't be any
>  jb> cost benefit to build them yourself either. 
> 
> I agree, also...
> 
> Not only are many things hidded, but things is a bit more obscure than
> you might find in analog cursuits. The frequency wrapping, the yeat
> harder math, the impact of low resolution/quantization etc. all add
> up.
> 
> Another thing is the availablility of free tools.
> 
> Yeat further reasons is that adapting it into the environment of
> things that one already has is greater. With analogs you maybe just
> need to adjust the signal levels or so, for control signals it is the
> linear/expo limit that is among the more expensive ones that one
> usually see, but it is still at a fairly low level after all.
> 
> Also, when you actually build something the complexity grows on you,
> you quickly run into packages with many signals, more and more surface
> mounting, timing, high frequency problems etc.
> 
> Mastering each of these fields enought certainly filters many people
> out.
> 
> Never the less, it is fun to play with the thoughts.
> 
> Lately I have playing with the idea of using PICs for simpler tasks,
> they are not the strongest DSPs, MCUs or CPUs you may find, but they
> fit the smaller range. There are free tools available and a lot of
> material online. They come in fairly small packages at a decent price.
> The assembler has it sides, but you can do stuff with it. They may not
> glue up with A/Ds and D/As as obviously simple as a larger DSP would,
> but there are hints on how to do this aswell. It seems fairly
> promessing.
> 
> Cheers,
> Magnus
> 
> 

------------------------------------------------------------------------------
tsheets at saturn5.com                        <- You have found me   
http://www.saturn5.com/tsheets/audio       <- my .mp3 tracks
http://www.saturn5.com/tsheets/Casey3.wav  <- Casey Kasem in rare form



From rsowa at WizjaTV.pl  Tue Jan  5 19:12:44 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 5 Jan 1999 19:12:44 +0100 
Subject: ODP: Digital DIY synths?
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D684E@demon>

Hi Ben and all,

Good to hear that someone is into DSP too...
Like others said, it is somehow harder to DIY in digital
and less fun too (at least for me), but things like
frequency shifter, or strange waveshaping I'd only
do in DSP.
I was very much convinced that my next gear would be
all-DSP until I subscribed to this list.
It's nice to have drift-free oscilators and excellent tracking
filters, but it involves so much of hitting-the-PC-keyboard...
and when you do analog, whatever you do it works in some way
not exactly what one wants, but nice too. with DSPs it's just
a matter of small error to have no signal at DAC output.

I'll return to this subject anyway, but first few analogs will
appear. I have some experience with this particular DSP
so maybe we could build something with it.

BTW seems like you have ezkitlite...
I never liked it, so I made my own system.
if you like, you might take a look:
http://www.multimania.com/romcio/evm2181.html

This isn't the best way to introduce my new (or rather first)
website since it's not finished yet (and never will be...)
But anyhow many thanks to all who replied to my question
regarding website providers.
And special thanks to greg.

Roman


> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	5 stycznia 1999 00:58
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Digital DIY synths?
> 
> Hello all,
> 
> I've been on this list for a few weeks now, and I'm enjoying a lot of your
> 
> messages. However, the focus is purely on analog DIY synths. Are digital  
> synths considered heretical here? You see, one of the main disadvantages I
> see  
> with the pure analog way of doing things is that it is hard to reproduce
> the  
> sound or performance afterwards. (I used to have a Teisco 110F in the
> early  
> eighties, so I know.) You could go with digital pot's from e.g. Dallas and
> run  
> the whole thing through midi I guess.
> 
> I'm asking because I just got this DSP demo board from Analog Devices,
> with  
> an ADSP2181 DSP, stereo A/D and D/A, and rs232 port. It seems to me it
> would  
> be fun writing software emulating an analog synth. (Like the current crop
> of  
> analog modeling synths, the Yamaha An1x, Access Virus, Clavia and Waldorf
> 
> stuff, etc.)
> 
> Anybody with experience with this?
> 
> With kind regards, and I hope I did not offend anyone... B-)
> Ben



From Juergen.Haible at nbgm.siemens.de  Tue Jan  5 19:17:04 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 5 Jan 1999 19:17:04 +0100 
Subject: AW: Filters?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582011517E5@nbgm336a.nbgm.siemens.de>

	>What we found out, was, that the differences between two devices of
the same  
	>type (Rogue, TR303) were bigger than the difference between the
different  
	>brands!
	>
	>Especially the behavior over a wide frequency range differred a
lot.

Great findings indeed. So these tiny electronic components 
do care more about the way they are arranged, than for the 
nameplate on the enclosure ? (Sorry, couldn't resist.)

JH.




From oakley at techrepairs.freeserve.co.uk  Tue Jan  5 19:42:58 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Tue, 5 Jan 1999 18:42:58 -0000
Subject: BA6110 and pcb orders
Message-ID: <000501be38db$3a782c20$cb06883e@default>

Hi All,

Due to public request I may have to try out the above part as a sub for
the 662. Has anyone tried it yet?

Does anyone want any more VCF-1 pcbs, because I may just order some more
from a new supplier? Resolution circuits went bust.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From magnus at analogue.org  Tue Jan  5 19:43:59 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 05 Jan 1999 19:43:59 +0100
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: Your message of "Tue, 05 Jan 1999 09:40:29 -0800"
References: <36924E13.31DF@ptdcs2.intel.com>
Message-ID: <199901051844.TAA19403@mail2.it.kth.se>

>>>>> "DRB" == Duane R Balvage <dbalvage at ptdcs2.ra.intel.com> writes:

 DRB> Hello all -
 DRB> Is there anyone out there who has any basic guidelines on how many dB
 DRB> down "aliasing" frequencies have to be so they are not a problem?

 DRB> I'm retrofitting my Prophet-2000 sampler with 2 switched-cap
 DRB> 6-pole filters in series (12 poles, 72 dB/oct) for the antialiasing
 DRB> filter. (The antialiasing filters in it now are a bit, uhh, conservative
 DRB> to say the least) Right now they sit at:

 DRB> 41Khz sample rate : 16Khz corner freq.
 DRB> 32Khz sample rate : 12Khz corner freq.
 DRB> 24Khz sample rate : 9Khz  corner freq.

Ugh!

Is this the reason people have considered oversampling? Certainly.

 DRB> They are using 4 pole input filters (I think - have to check the schems)
 DRB> so the slopes are a bit gradual, taking off some of the "sparkle" of
 DRB> the samples because they have to have their corner frequency set low 
 DRB> enough to avoid aliasing. Any suggestions???

The benefit of 48 db extra per octave allows us to move the cutoff
upwards. I made some quick calculations and assuming that we require
the same damping at the nyquist point, we can move it to

41 kHz	18.85 kHz
32 kHz	14.4 kHz
12 kHz	10.6 kHz

This using a very crude method (basically using a Bode-plot fashion of
view and let the nyquist frequency be the common intersection point) .

Cheers,
Magnus



From costello at seanet.com  Tue Jan  5 21:00:08 1999
From: costello at seanet.com (Sean Costello)
Date: Tue, 05 Jan 1999 12:00:08 -0800
Subject: Serge
References: <3692D97A.588D@swipnet.se>
Message-ID: <36926F48.3A6B4D8F@seanet.com>

BJ wrote:
 
> The serge VCO's are mentioned from time to time on the list
> like this above, so how are they designed??Is there any shemo
> somewhere on the net who covers the entire VCO design??

I don't know of any schematic, and I've searched.  However, someone on
this list (Grant Richter maybe?) has said that the New Timbral
Oscillator uses a CA3046 as the exponential convertor, using heated chip
technology (i.e. what has been discussed in the past few days).  

Sean Costello



From guidogoe at xs4all.nl  Tue Jan  5 21:17:50 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Tue, 05 Jan 1999 20:17:50 GMT
Subject: Test posting
Message-ID: <915564000-412659AEicMi@xs4all.nl>

Hi there, I'm new to this party.
So this is a test posting.
So: Test 1,2,3...
 
Greetings, Guido




From bduggan at netcom.com  Tue Jan  5 21:47:10 1999
From: bduggan at netcom.com (Brett Duggan)
Date: Tue, 5 Jan 1999 12:47:10 -0800 (PST)
Subject: Sherman Filterbank service manual?
Message-ID: <Pine.3.89.9901051204.A4870-0100000@netcom10>


Hi everyone,

I was wondering if anyone here on the list has the service manual for the 
Sherman Filterbank?  If so, could you please email me?

Thanks,
Brett D




From cyborg0 at GlobalEyes.net  Tue Jan  5 22:14:39 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Tue, 05 Jan 1999 15:14:39 -0600
Subject: ARP Odyssey AR Hacked
References: <36924B3A.6965@sprint.ca>
Message-ID: <369280BF.194773F@globaleyes.net>

|||| Philip Pilgrim |||| wrote:
> 
> Hi all,
> 
> I used the simple Arp AR envelope from the Odyssey in my SH-101 NovaMod
> upgrade (due to it's simplicity) but was never really satisfied with it.
> The main problem was that the envelope could not be re-triggered by a
> new key press thus it had a portamento-ish amplitude slurring.
> 
> A few people on this list requested that I update them if I ever figured
> out how to re-trigger the env....well here it is:
> 
> I finally had a chance to hack the circuit in my typical crude but
> usually functional fashion and found that by adding a resistor and
> transistor, the circuit could now accept a re-trigger signal. I never
> checked to see if the odyssey had an available trigger signal however
> the SH-101 has a hi to low transition trigger which I used (found at R36
> on synth board btw).
> 
> The attached AR circuit (re-annotated from the Odyssey values) has the
> two new parts R7 and Q3 added. It is obvious that the negative
> trigger-in switches the transistor Q3 and drains the charge on the cap
> C2 thus resetting the output to 0V.
> 
> For positive pulse triggers simply use a NPN (2N5172).
> 
> Finally the attack and decay times can be increased by increasing the
> value of C2. I experimented last evening and found 4.7uf very useful.
> 
> All of these improvements should be easy to do on an odyssey from the
> solder side of the board :)
> 
hohoooo! nifty! The Oddy always sounded less that crisp due to this
non-retriggerability..
Rob



From ben at stuyts.nl  Tue Jan  5 22:31:36 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue,  5 Jan 99 22:31:36 +0100
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: <36924E13.31DF@ptdcs2.intel.com>
References: <36924E13.31DF@ptdcs2.intel.com>
Message-ID: <199901052131.WAA07866@daneel.stuyts.nl>

Hello,

On Tue, 05 Jan 1999, Duane R Balvage wrote:

> Is there anyone out there who has any basic guidelines on how many dB
> down "aliasing" frequencies have to be so they are not a problem?
>
> I'm retrofitting my Prophet-2000 sampler with 2 switched-cap
> 6-pole filters in series (12 poles, 72 dB/oct) for the antialiasing

I'm not 100% sure about this, so correct me if I'm wrong but...

You have to be very careful with switched cap filters when using them for  
anti-aliasing purposes. As they themselved are sampling systems, they will  
need an anti-alias filter at the input, or else you will get aliasing in the  
filter. So if they switch at, say, 40 kHz, you will definitely need to make  
sure nothing above 20 kHz gets in! Which kind of makes the switched-cap  
excercise futile.

Best regards,
Ben



From brun at bart.nl  Tue Jan  5 23:16:14 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Tue, 5 Jan 1999 23:16:14 +0100
Subject: Looking for Korg 700s schems
Message-ID: <199901052216.XAA21460@Njord.bart.nl>

Well, the subject line says it all - I've been asked to help a Korg 
700s-owner out with schematics for his machine. Anyone care to 
help? Thank you! 






--> Brun, met een dakje op de u.

Nu ook op http://www.bart.nl/~brun/index.htm



From tom.verheyden at village.uunet.be  Tue Jan  5 23:31:41 1999
From: tom.verheyden at village.uunet.be (be053520)
Date: Tue, 5 Jan 1999 23:31:41 +0100
Subject: 3904/3906 tranny specs
Message-ID: <00cb01be38fe$61d8cf40$6c5907c2@be053520>

Rob wrote:


>Since I am using the transistors as switches, I wouldnt think Vbe=Vc as
>being a problem.
>
>let me know..
>Rob


No, not really...
But I've experienced another nasty thing about trannies as a switch.
The transistor was used in a voltage-shifter circuit and I had to connect a
square-generator (about 1Hz) to it.
I started the generator and left it alone for about half an hour.
When I came back the tranny was broken.
When I compared load-line and transistor-curve (ofcourse after the usual
cursing and wishing all trannies to hell :-))it seems to be that the
Vbe-capacitor (specific to every tranny) was the cause.
The transistor has switched to slow (the cap slowed it down) between on and
off-state, became hot and broke down...

Never got this problem before...

Strange huh, any other explainations?

bye

Tom Verheyden.






From guidogoe at xs4all.nl  Tue Jan  5 23:42:50 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Tue, 05 Jan 1999 22:42:50 GMT
Subject: PAIA?
Message-ID: <915572826-936148AEicMi@xs4all.nl>

Hi there once more,

Now that I see my mail is coming thru...
And yes, mr. BJ from Sweden, thank you for the welcome, but weren't you supposed to be in the A-team rocking your own party?
Thought so. (1,2,3, and off you go!)
Now for the serious stuff:
I'm planning to build a FATMAN from PAIA, as I have built lots of Vc-filters, ENV-generators and LFO's in the past years which I now intend to connect to the FATMAN, to expand it, e.g. use it as the base of a modulair system.
I always considered building VCO's/ MIDI to CV- converters as a bit to difficult etc., but maybe I can
learn from the PAIA-kit, or from you all out there.
Most of the stuff I constructed uses the old faithfull
CA 3080, LM 13600 and SSM's like the 2024 quad CCA.
I think I it will add nice to my over-digitalized set-up.
Anyone who has any experience with this out there?
Yes? Tune me in, please.
As for the DSP-part of the discussion, I bought my CLAB-falcon with that in mind, but as the ATARI-scene is a bit going under nowadays, it is so hard to obtain
good devolopment-software, so I dropped that idea, I quess. So sad. :((

Guido




From harv23 at leland.Stanford.EDU  Tue Jan  5 23:46:46 1999
From: harv23 at leland.Stanford.EDU (Harvey Devoe Thornburg)
Date: Tue, 5 Jan 1999 14:46:46 -0800 (PST)
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: <199901051844.TAA19403@mail2.it.kth.se> from "Magnus Danielson" at Jan 5, 99 07:43:59 pm
Message-ID: <199901052246.OAA01553@amy7.Stanford.EDU>

> 
> >>>>> "DRB" == Duane R Balvage <dbalvage at ptdcs2.ra.intel.com> writes:
> 
> Is this the reason people have considered oversampling? Certainly.
> 
>  DRB> They are using 4 pole input filters (I think - have to check the schems)
>  DRB> so the slopes are a bit gradual, taking off some of the "sparkle" of
>  DRB> the samples because they have to have their corner frequency set low 
>  DRB> enough to avoid aliasing. Any suggestions???
> 
> The benefit of 48 db extra per octave allows us to move the cutoff
> upwards. I made some quick calculations and assuming that we require
> the same damping at the nyquist point, we can move it to
> 
> 41 kHz	18.85 kHz
> 32 kHz	14.4 kHz
> 12 kHz	10.6 kHz
> 
> This using a very crude method (basically using a Bode-plot fashion of
> view and let the nyquist frequency be the common intersection point) .
>

This assumes that all of the poles are at the same frequency, right?
Maybe it is possible to distribute them somehow such that the slope
is steeper at the Nyquist frequency, or such that the response is
an even better approximation to a "brickwall" lowpass.  Elliptic
filters give you the best approximation, in the sense of minimizing
the maximum of the difference between your filter's response and the
desired "brickwall" response.

Unfortunately, elliptic filters as well as cascaded one poles have 
a highly nonlinear phase response.  This means certain frequencies
will be delayed relative to others. I would guess this becomes a 
bad problem near the Nyquist frequency. There is another type of filter
(called Bessel filter) which has approximately linear phase, but a more
gradual cutoff.  IMHO, nonlinear phase is not so important for a sampler,
but for "high-end" or mixing applications, recording engineers swear by
it.  Also in communications it is important not to distort the shape of 
the waveform; most of the "shape" information is contained in the pahse. for 
these reasons all of the DAC's I've seen employ Bessel filters, something 
like 6-8th order(*).  if this were my project I would try elliptic filters.

--Harvey




From magnus at analogue.org  Wed Jan  6 00:37:36 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 06 Jan 1999 00:37:36 +0100
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: Your message of "Tue, 5 Jan 1999 14:46:46 -0800 (PST)"
References: <199901052246.OAA01553@amy7.Stanford.EDU>
Message-ID: <199901052337.AAA21373@mail2.it.kth.se>

>>>>> "HDT" == Harvey Devoe Thornburg <harv23 at leland.Stanford.EDU> writes:

Hi Harvey and others!

 >> 
 >> >>>>> "DRB" == Duane R Balvage <dbalvage at ptdcs2.ra.intel.com> writes:
 >> 
 >> Is this the reason people have considered oversampling? Certainly.
 >> 
 DRB> They are using 4 pole input filters (I think - have to check the schems)
 DRB> so the slopes are a bit gradual, taking off some of the "sparkle" of
 DRB> the samples because they have to have their corner frequency set low 
 DRB> enough to avoid aliasing. Any suggestions???
 >> 
 >> The benefit of 48 db extra per octave allows us to move the cutoff
 >> upwards. I made some quick calculations and assuming that we require
 >> the same damping at the nyquist point, we can move it to
 >> 
 >> 41 kHz	18.85 kHz
 >> 32 kHz	14.4 kHz
 >> 12 kHz	10.6 kHz
 >> 
 >> This using a very crude method (basically using a Bode-plot fashion of
 >> view and let the nyquist frequency be the common intersection point) .
 >> 

 HDT> This assumes that all of the poles are at the same frequency, right?

Nope. It just assumes that their common responce resulted in the -3.01
dB point at the given frequencies and that their common slope where
-6.02 dB per octave and pole.

 HDT> Maybe it is possible to distribute them somehow such that the slope
 HDT> is steeper at the Nyquist frequency, or such that the response is
 HDT> an even better approximation to a "brickwall" lowpass.  Elliptic
 HDT> filters give you the best approximation, in the sense of minimizing
 HDT> the maximum of the difference between your filter's response and the
 HDT> desired "brickwall" response.

Well, actually, the -6 dB slop per octave _AND POLE_ is kind of
inherent if the poles sits in a brick wall optimisation like
Butterworth or Chebyshev (both are likely candidates here).
It is however true that Elliptic filters have even steper slopes, but
this is due to the fact that they also places zeros near the slope
region in the stop band instead of placing them in infinity (as with
Butterworth, Bessel or Chebyshev does).

Also, note that he was using integrated switch capacitor filters these
are very likely to be either Butterworth (maximum passband flatness)
or Chebyshev (maximum steepness). Elliptic/Cauer filters is rarely
seen in these filters, but they are fully realizable aswell.

 HDT> Unfortunately, elliptic filters as well as cascaded one poles have 
 HDT> a highly nonlinear phase response.  This means certain frequencies
 HDT> will be delayed relative to others. I would guess this becomes a 
 HDT> bad problem near the Nyquist frequency. There is another type of filter
 HDT> (called Bessel filter) which has approximately linear phase, but a more
 HDT> gradual cutoff.

Yes, Bessel/Thomson filters is really the maximum flat groupdelay
approximation to the brickwall filter.

In these respects the Chebyshev filters are just terrible and a
Butterworth is much smoother and Bessel further better, especially
when you get up to higher degrees (where Butterworth filters gets a
stonger bump in the groupdelay at the cutoff frequency).

 HDT> IMHO, nonlinear phase is not so important for a sampler, but for
 HDT> "high-end" or mixing applications, recording engineers swear by it.

On the other hand, there is not such a big difference after all in how
you design, and my experience tells me that smother, quieter filters
are usually prefered in the long run. The less strange things that
happends with the sound, the better. Yeat again, we are talking about
what happends in the over range, and dropping in a few zeros to kick
out distorsion effect is well worth it.

 HDT> Also in communications it is important not to distort the shape of 
 HDT> the waveform; most of the "shape" information is contained in the pahse. for 
 HDT> these reasons all of the DAC's I've seen employ Bessel filters, something 
 HDT> like 6-8th order(*).  if this were my project I would try elliptic filters.

When you talk about telephone cursuits you must also recall that for
longer runs they do echo-cancelling, and the screwier they get the
frequency and phase/group-delay responce, the hard work it
becomes. They have pure economics and reality of life pointing fingers
for them.

As for real communication curcuits (like SDH/SONET/PDH lines) long
runs of lines require many transponders which must resample the data
with a recovererd clock. Due to jitter accumulation and requirements
for low bit error rates is peaking in the phase responce of the clock
recovery an critical issue (an peaking of 0.05 dB is an issue for
these people).

Cheers,
Magnus




From ben at stuyts.nl  Wed Jan  6 00:42:58 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 00:42:58 +0100
Subject: Digital DIY synths?
In-Reply-To: <ISSMTP.1.3(1).19990104164120.4294106303B@Corp.wdc.com>
References: <ISSMTP.1.3(1).19990104164120.4294106303B@Corp.wdc.com>
Message-ID: <199901060004.BAA07991@daneel.stuyts.nl>

On Mon, 4 Jan 1999, Barry L Klein wrote:

> I received the same kit after attending one of AD's seminars.  Do these
> other synths you mention use this same 2181 chip?

They use all kinds of chips. I think the Nord's and/or Acces Virus use  
multiple Moto 563xx parts. My Zoom 1504 effect processes uses a TI TMS320  
derivative, and it can do pitch shifting, vocoding, plus the usual assorti of  
delays. I don't know of any synth that uses the 2181, but I happened to get my  
hands on the eval kit. That's why I was interested in using it for music.

>  At the seminar they
> demo'd a SHARC-based synth, which is a much more powerful chip, but it
> sounded pretty cheasy.

The demo 2181 board comes with a demo 'Stairway to heaven' song on a plucked  
guitar-like waveform. (Wayne's World?) It sounds pretty awful too.

> I think most of us would love to hear of digital synth attempts.  I
> haven't heard of any modular designs using that approach.

The Nord Modular uses that approach, but it is commercial and very expensive.  
You draw patch leads on a winblows program. Cute.

>  DSP chips like
> the 2181 are so cheap that it should be cheaper to do it with them than
> the custom analog chips.

Yep, the dsp eval board are usually around $100, and include full docco,  
assembler, etc.

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 00:56:12 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 00:56:12 +0100
Subject: Digital DIY synths?
In-Reply-To: <199901050147.RAA28946@amy7.Stanford.EDU>
References: <199901050147.RAA28946@amy7.Stanford.EDU>
Message-ID: <199901060004.BAA07994@daneel.stuyts.nl>

On Mon, 4 Jan 1999, Harvey Devoe Thornburg wrote:

> I think this has more to do with the interface (knobs) than the
> quality of components.  It is definitely possible to get repeatable
> sounds out of analog synths with a certain level of design.

Yes, but having programmable presets on an analog diy synth would be kind of  
nice. Has anybody done anything in thar area? It shouldn't be to difficult now  
that digital pot ic's are so common.

One other thing that I'm missing from pure analog synths is the fact that you  
can only record the end product, the output wave. You cannot record your  
performance in, for example, a midi sequencer. I recently got interested again  
in analog synths, and thought I'd buy a paia fatman kit. Then I looked at the  
Waldorf Pulse, which is a DSP based analog modeling synth, where they used  
the fact that all controls are available (in and out) through midi. I thought  
that was a pretty good point. Anyway, while looking in the shops for these  
kind of instruments, I found the Yamaha An1x, which I could try out over the  
holiday. (Yep, gonna keep it!) The whole DSP thing started to make more and  
more sense to me. Not to mention being able to use it polyphonically. (sp?)

Don't get me wrong though. I'm an electronics software *and* hardware  
designer by profession (mostly embedded turf), and I like them both. I have  
looked at and enjoyed a lot of the web pages the people on this list have  
published recently.

In contrast to a few of the replies here, I do not consider the whole  
software thing more difficult or less arty than the hardware approach. I think  
it is more a state of mind thing. I think one can just as well enjoy tweaking  
a musical algorithm for sound quality (or lack of! B-)) and performance, as  
one can enjoy tweaking R's and C's.

> You might also be interested in the music-dsp list.  About 70% of
> the posts are about audio DSP stuff, the other 30% discuss a
> certain member who likes to flood the list with manifestoes and
> machine gibberish (I personally find him/her entertaining, and he/she
> has developed some interesting software).  find out more at
> http://shoko.calarts.edu/~glmrboy/musicdsp/music-dsp.html

Thank you, I've subscribed immediately. I haven't seen any messages yet though.

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 00:59:45 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 00:59:45 +0100
Subject: Digital DIY synths?
In-Reply-To: <1.5.4.32.19970331114326.0072d4ac@popa.melbpc.org.au>
References: <1.5.4.32.19970331114326.0072d4ac@popa.melbpc.org.au>
Message-ID: <199901060004.BAA07997@daneel.stuyts.nl>

On Mon, 31 Mar 1997, Paul Perry wrote:

> A friend has built his own DSP monosynth from an AD dsp
> evaluation board (heard it in use at my local pub when he played it on
> New Years Eve).
> He was pretty pissed at how difficult it was to get a good sound, but

I can imaging that. One of the advantages of analog synth design is that  
there's so much out there, so many examples. With DSP synth's there's a lot  
less info, and you have to start from scratch. Anyway, I also have a theremin,  
so I'm used to awful sounds. (More due to the performance of the player, of  
course. <grin>)

> cheered up when he heard a Nord. It's a LOT better than that..

I played a Nord Lead a few weeks ago. I actually thought it was the worst of  
the lot I tested. The Access Virus was the best, sound wise, and the Yamaha  
An1x was the most fun to play with.

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 01:04:29 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 01:04:29 +0100
Subject: Digital DIY synths?
In-Reply-To: <TFSACUTG@idg.se>
References: <TFSACUTG@idg.se>
Message-ID: <199901060004.BAA07988@daneel.stuyts.nl>

On Tue, 5 Jan 1999, jorgen.bergfors at idg.se wrote:

> The main reason analog is more popular among DIY types is that it is much
> more suited to DIY. You can build almost any circuit with standard parts and
> if it doesn't work, you can follow the signal with an oscilloscope to
> diagnose it. With digital, almost everything is controlled by software. That
> means it is impossible to change unless you have access to the source code.

Well, the whole idea is that you design the source code, so access shouldn't  
be a problem.

> Also digital synths normally use special-purpose ICs, which can't be bought
> from an electronics supplier.

DSP's are pretty common parts nowadays. And the eval kits can be bought from  
most distributers for $100 or so.

> You also need special equipment, like
> PROM-burners and such, to do digital.

Nope, you just download code to the eval board. You can burn it in prom, of  
course, but that would mean you would have finished it. B-)

> And with the low prices of
> mass-produced digital synths, there wouldn't be any cost benefit to build
> them yourself either.

That's no argument. I guess there are a lot of people who have put more money  
in DIY than economically makes sense. The main point of DIY is (imho) the fun  
of actually creating something (be it hardware or software), and learning  
from it.

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 01:12:31 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 01:12:31 +0100
Subject: Digital DIY synths?
In-Reply-To: <199901050947.KAA15300@mail2.it.kth.se>
References: <TFSACUTG@idg.se> <199901050947.KAA15300@mail2.it.kth.se>
Message-ID: <199901060012.BAA08004@daneel.stuyts.nl>

On Tue, 05 Jan 1999, Magnus Danielson wrote:

> Lately I have playing with the idea of using PICs for simpler tasks,
> they are not the strongest DSPs, MCUs or CPUs you may find, but they
> fit the smaller range.

You could build a modular hybrid synth. For example, use an a/d -> cpu ->  
d/a. I've been thinking about that. The cpu could be a cheapo, like the faster  
8051 parts or the Scenix ones. (They are more or less PIC compatible but run  
at 50 MHz, all in a dip package.) The problem is that 16 bit a/d and d/a are  
still expensive. Maybe one of the audio codec's (e.g. AD1847 as used in pc's)  
would fit. Or, for fun, one could test the whole idea with 8 bit a/d and d/a.  
Makes the software much easier too.

The problem with this whole idea is of course that cost go up pretty quickly  
if you want a full modular this way. But I can imagine that a PIC with an 8  
bit DAC would make a nice envelope generator.

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 01:24:46 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 01:24:46 +0100
Subject: Digital DIY synths?
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D684E@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D684E@demon>
Message-ID: <199901060024.BAA08011@daneel.stuyts.nl>

On Tue, 5 Jan 1999, Roman Sowa wrote:

> I'll return to this subject anyway, but first few analogs will
> appear. I have some experience with this particular DSP
> so maybe we could build something with it.

That would be fun.

> BTW seems like you have ezkitlite...
> I never liked it, so I made my own system.
> if you like, you might take a look:
> http://www.multimania.com/romcio/evm2181.html

I just looked at it. It looks *very* nice. Will your software by any chance  
run on the ezkit lite? B-)

What exactly didn't you like about the ezkit? Too noisy?

BTW, I've downloaded a nice set of demo's and experiments for the ezkit. It  
is at http://www.ece.rutgers.edu/~orfanidi/ezkitl/ezkitl.html

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 01:30:08 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 01:30:08 +0100
Subject: Digital DIY synths?
In-Reply-To: <199901051757.JAA18290@atari.saturn5.com>
References: <199901051757.JAA18290@atari.saturn5.com>
Message-ID: <199901060030.BAA08018@daneel.stuyts.nl>

On Tue, 5 Jan 1999, Troy Sheets wrote:

> Plus, working on analog circuits is just more of an art.  There
> are so many more variables... Simple things like how well you have
> matched a transistor pair have subtle influences on the sound
> quality... how hard you drive your filter, ect.

Isn't it also the fun in designing a dsp based synth to make these things  
matter? To introdoce non-perfect saw pulses, to introduce non-linear  
transmission? I agree that a pure analog synth is more 'visible', but as I  
said in another message, I think it is just a matter of state of mind. In a  
dsp based synth, you are not trying to make the perfect mathematical pulse  
signal. That would be easy. You are trying to make the most musically pleasing  
pulse signal.

>  It is these
> little details that make your own analog synth a real unique
> artistic tool.  Plus, I don't know... I just think analog circuits
> have more "life" in them... they breathe and pulsate and you can hear
> the electrons squirting through your circuits.   Digital is just more
> sterile and mathmatic.

There's just as much electrons in them DSP's... This sound like it could grow  
out to an audiophile type of war. TUBES, USE TUBES! B-)

Best regards,
Ben



From ben at stuyts.nl  Wed Jan  6 01:37:42 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 01:37:42 +0100
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: <199901052131.WAA07866@daneel.stuyts.nl>
References: <36924E13.31DF@ptdcs2.intel.com>
	<199901052131.WAA07866@daneel.stuyts.nl>
Message-ID: <199901060037.BAA08027@daneel.stuyts.nl>

On Tue,  5 Jan 99, I wrote:

> > I'm retrofitting my Prophet-2000 sampler with 2 switched-cap
> > 6-pole filters in series (12 poles, 72 dB/oct) for the antialiasing
>
> I'm not 100% sure about this, so correct me if I'm wrong but...

And wrong I was...

> You have to be very careful with switched cap filters when using them for
> anti-aliasing purposes. As they themselved are sampling systems, they will
> need an anti-alias filter at the input, or else you will get aliasing in the
> filter. So if they switch at, say, 40 kHz, you will definitely need to make
> sure nothing above 20 kHz gets in! Which kind of makes the switched-cap
> excercise futile.

Duane pointed out to me that they actually sample at 50 times their cut-off  
frequence, so it is less of a problem. However, I've had problems with this in  
the past, but it was soooo long ago, that I forgot the details. I had a  
switched cap filter at 10 Hz for a low frequency amp, and I did have trouble  
with interference up to a few 100 Hz.

Best regards,
Ben



From amieuss at telcel.net.ve  Wed Jan  6 04:28:07 1999
From: amieuss at telcel.net.ve (Arturo Mieussens)
Date: Tue, 5 Jan 1999 23:28:07 -0400
Subject: OT:  Roland Space Echo Schematic
Message-ID: <19990106033303.AAA16959@mail01.t-net.net.ve@arturomi>


> De: Peter Blackett <dragonser at clara.net>
> A: Arturo Mieussens <amieuss at telcel.net.ve>
> Asunto: Re: OT:  Roland Space Echo Schematic
> Fecha: lunes 4 de enero de 1999 20:21
> 
> Dear Arturo,
> which Roland space echo is it ?

Space Echo RE-201

> Parts are hard to get hold off. Roland UK don't have any pinch wheels in
> stock , or any tape loops .

I'm lucky enough to have a "new" box of tapes (RT-1L echo chamber tape) and
a second working Space Echo.

Dealing with the venezuelan distrubutor is anything but a pleasure, they
refuse to do any servicing to equipment bought anywhere else. They once
refused to get me an LCD screen for an XP-10 I bought in a trip to the
states. I don't know what Roland would think of their behaviour but I have
though of writing them about it.

So if anybody could  scan or sell me a copy I would be gratefull.

Thanks, please keep me informed.
Arturo
amieuss at telcel.net.ve



From zzynt at swipnet.se  Wed Jan  6 04:33:14 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 05 Jan 1999 19:33:14 -0800
Subject: Serge
Message-ID: <3692D97A.588D@swipnet.se>

> I think this has more to do with the interface (knobs) than the
> quality of components.  It is definitely possible to get repeatable
> sounds out of analog synths with a certain level of design.
> VCO's with adequate temperature compensation (such as those used
> in Serge equipment) simply do not drift: you can run a complex
> FM patch for days and it will sound very much the same. 

The serge VCO's are mentioned from time to time on the list
like this above, so how are they designed??Is there any shemo
somewhere on the net who covers the entire VCO design??

Im curious!!

BJ



From da5id at vision.net.nz  Wed Jan  6 05:10:04 1999
From: da5id at vision.net.nz (David Shipman)
Date: Wed, 06 Jan 1999 16:10:04 +1200
Subject: Introduction
Message-ID: <yam7675.236.2018189848@smtp.sinesurf.co.nz>

Just thought I'd drop a line to introduce myself to the list...

I'm into electronic music, particularly noisy experimental stuff along
the lines of Einsturzende Neubauten...

My electronics experience is limited to high school physics, although
I can read schematics and am fairly handy with a soldering iron...

In particular I'd like to build some sound processing devices, perhaps
a modular sound processor along the lines of Kevin Lightner's
Polyfusion rig...

I'm also interested in modding synths (especially the wonderful SH-5,
and also fairly useless devices such as all the cheap dodgy Casio
stuff floating around...) and other sound devices (radios, tape
recorders, telephones etc)

I'd like to get a modular synth (Doepfer etc), and in the long term,
build my own, but of course this isn't going to by my first project :)

I'm not sure about the range of topics discussed here, but if anyone
has experience with custom pickups for Sitars, Mandolins and other less
convential string instruments, I'd be interested in hearing from them
too...

Thanks,

-- 
David Shipman
Email : david at vision.net.nz
WWW   : http://www.vision.net.nz/david/




From zzynt at swipnet.se  Wed Jan  6 06:45:17 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 05 Jan 1999 21:45:17 -0800
Subject: Serge
References: <3692D97A.588D@swipnet.se> <36926F48.3A6B4D8F@seanet.com>
Message-ID: <3692F86D.61CB@swipnet.se>

Sean Costello wrote:
> 
> BJ wrote:
> 
> > The serge VCO's are mentioned from time to time on the list
> > like this above, so how are they designed??Is there any shemo
> > somewhere on the net who covers the entire VCO design??
> 
> I don't know of any schematic, and I've searched.  However, someone on
> this list (Grant Richter maybe?) has said that the New Timbral
> Oscillator uses a CA3046 as the exponential convertor, using heated chip
> technology (i.e. what has been discussed in the past few days).
> 
> Sean Costello

Hip hip horrayyyy!! 
That means that I'm not the only one who does oven 
controlled expoconverter with a LM3046.

BJ
(in horrayable land.)



From zzynt at swipnet.se  Wed Jan  6 06:48:24 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 05 Jan 1999 21:48:24 -0800
Subject: Test posting
References: <915564000-412659AEicMi@xs4all.nl>
Message-ID: <3692F928.1B15@swipnet.se>

Guido Goebertus wrote:
> 
> Hi there, I'm new to this party.
> So this is a test posting.
> So: Test 1,2,3...
> 
> Greetings, Guido

A one, a twoo, a three, bomm shlabong ,lets rock a tune!

BJ



From zzynt at swipnet.se  Wed Jan  6 07:03:17 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 05 Jan 1999 22:03:17 -0800
Subject: CA3046 exponential converter
References: <368E610E.13C89E69@k-online.com> <369223C0.E2B2715B@k-online.com>
Message-ID: <3692FCA5.7690@swipnet.se>

Steve Varner wrote:
> 
> I guess not many people have built the 3046 VCO and thermostat as shown in
> Klein's book. The difference between this design and the AN-299 design is
> that the matching transistors and one other transistor are used in the
> standard VCO way, and the last two are used for temperature sensing and
> heating. There is no transistor used for the clamp. I'll try this design
> and let people know how it works.
> 
> SV
> 
> --------------------------------------
> Steve Varner wrote earlier:
> 
> > Barry Klein has a CA3046 exponential converter (fig.4-4, p.87) in his
> > "Electronic music circuits." This is the same as the ENS-76 VCO option
> > 1A found in the "Preferred Circuits Collection." These schematics show
> > temperature compensation using the 2k tempco.
> > Barry also has a CA3046 2-transistor thermostat circuit (Fig. 4-3, p.86)
> > using the remaining transistors on the array (Q4 and Q5). It seems very
> > simple. (I suppose you would then leave off the tempco resistor and
> > replace it with a regular resistor.)
> > Has anyone built this exact VCO setup? If it works well... godbye
> > matched pairs and tempcos for me. 3046's only cost about 35 cents.

> > Steve Varner
> > mailto:varner at k-online.com

I dont know about you other but the oven controlled expoconverter
works wery well, wery wery well i would say, one example is the
Moog Source, who happens to have a oven expo, a little clumsy
design but wer well working.Remembering the test i did again
with a mates source this winter.
Rock solid tuning for several ours.

There is one point in the design of a oven controlled LM3046 you 
have to be avare off, and thats the value of the cappacitor 
for the ovens comparator ,when the two comparing
voltages are wery close to each other the comparator switches on 
to compensate for the temp drif,if the capp is small in value the
switching may be at several kilo herz and can produce interference
if a bad PCB layout is made or the VCO becomes "jittery"!

This "may" in a bad PCB design be one of the oven designs drawbacks!
But only if one are a neurotic personality!!!

In some designs i use a fairly large capp to get a slower response
of the comparator.

BJ's
5 cent



From cyborg0 at GlobalEyes.net  Wed Jan  6 08:35:26 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Wed, 06 Jan 1999 01:35:26 -0600
Subject: Digital DIY synths?
References: <ISSMTP.1.3(1).19990104164120.4294106303B@Corp.wdc.com> <199901060004.BAA07991@daneel.stuyts.nl> <36934965.1B58@swipnet.se>
Message-ID: <3693123E.6F3405A2@globaleyes.net>

BJ wrote:

> The Novation Drumstation uses a 2181/83 DSP for the percussion
> emulation.
> And some people say that the new Superstation uses the same DSP but a
> bounch
> of them!!
> Hmm, would be more apropriate to use a Sharc instead!

Well, no, not really, since you really only need to mix the signals and
we all know the in the DSP world, most of the work is the code.. If you
just have to jerry rig a bunch of them together to get what you want,
why not?

I like my drumstation, but putting two of them in one box is not going
to make me run out and buy a new one. I rarely run out of voices.. I
havent heard of the superdrumstation, and it seems like a dubious
project in the first place, unless they add stuff like filters, analog
waveforms, LFOs, and FX..
Now, THAT would be cool.. :)


Rob



From dmf at lotek.org  Wed Jan  6 09:25:48 1999
From: dmf at lotek.org (dmf)
Date: Wed, 06 Jan 1999 03:25:48 -0500
Subject: FS/T Stuff... More (Last time)
In-Reply-To: <3.0.6.32.19990104233334.007f4330@lotek.org>
References: <3.0.6.32.19990104142257.007ef100@lotek.org>
 <n1297781995.93454@smtp.directmedia.com>
Message-ID: <3.0.6.32.19990106032548.007d41c0@lotek.org>

Add one more thing this is the last time I'm posting, thanx...


Sci Pro-One $300 or Trade
Roland s330 sampler, good condition $225 or Trade
JLCooper midi patchbay 8x8 great condition $100 or Trade

Looking for the these in trade:

korg prophecy 
korg k3m
ms404
yamaha tg77
Presonus acp8 compressor
other rack synths make me an offer
thanx alot for your time, happy new year...



David





From zzynt at swipnet.se  Wed Jan  6 09:33:30 1999
From: zzynt at swipnet.se (BJ)
Date: Wed, 06 Jan 1999 00:33:30 -0800
Subject: PAIA?
References: <915572826-936148AEicMi@xs4all.nl>
Message-ID: <36931FDA.65DE@swipnet.se>

Guido Goebertus wrote:
> 
> Hi there once more,
> 
> Now that I see my mail is coming thru...
> And yes, mr. BJ from Sweden, thank you for the welcome,
> but weren't you supposed to be in the A-team rocking your own party?

? 
No, I am a C timer!

BJ



From irish at eskimo.com  Wed Jan  6 09:36:20 1999
From: irish at eskimo.com (Irish)
Date: Wed, 6 Jan 1999 00:36:20 -0800
Subject: (OT)Re: Digital DIY synths?
References: <199901060030.BAA08018@daneel.stuyts.nl>
Message-ID: <99010600424400.08380@Pandemonium>

On Tue, 05 Jan 1999, Ben Stuyts typed:
>On Tue, 5 Jan 1999, Troy Sheets wrote:

>> I just think analog circuits
>> have more "life" in them... they breathe and pulsate and you can hear
>> the electrons squirting through your circuits.   Digital is just more
>> sterile and mathmatic.
>
>There's just as much electrons in them DSP's... This sound like it could grow  
>out to an audiophile type of war. TUBES, USE TUBES! B-)

Tubes? You use tubes? Why, there WAY too sterile and precise. 
Use Switches!  Lots of switches and knobs and relays! You can *definetly*
feel the electrons in a setup like that! :P

Irish



From blacet at metro.net  Wed Jan  6 10:03:48 1999
From: blacet at metro.net (John Blacet)
Date: Wed, 06 Jan 1999 09:03:48 +0000
Subject: strobe lights and tempo
References: <009701be3986$96de3b20$53d26ccb@ppp.ozemail.com.au>
Message-ID: <369326F4.A34@metro.net>

This fellow has a MIDI to beat IC that can trigger a strobe via a
transistor:

http://www.maxmidi.com/diy/
-- 

Regards.
-------------------------
John Blacet
Blacet Research Music Electronics
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html




From rsowa at WizjaTV.pl  Wed Jan  6 10:18:45 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Wed, 6 Jan 1999 10:18:45 +0100 
Subject: ODP: Digital DIY synths?
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6851@demon>

Hi,

it will not run on ezkitlite - it requires some additional hardware,
but first prototype was made around ezkitlite itself (+5 or 6 ICs)

what I did'nt like? slow downloads, noisy codec and it's way of
programming, poor RS232 link, sometimes I couldn't download
new program into DSP without reseting the board.
And the PC software had like *no* features.
But maybe it was just my unit - I bought it in 1995 (?)

I downloaded those examples you're refering to.
Looks promissing. Will play with it this weekend hopefully.

BTW is there something wrong with the list?
I just don't receive posts any more :-(
or maybe delay increased from 4 hours to over 20?

Roman

> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	6 stycznia 1999 01:25
> Do:	Roman Sowa
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: Digital DIY synths?
> 
> On Tue, 5 Jan 1999, Roman Sowa wrote:
> 
> > BTW seems like you have ezkitlite...
> > I never liked it, so I made my own system.
> > if you like, you might take a look:
> > http://www.multimania.com/romcio/evm2181.html
> 
> I just looked at it. It looks *very* nice. Will your software by any
> chance  
> run on the ezkit lite? B-)
> 
> What exactly didn't you like about the ezkit? Too noisy?
> 
> BTW, I've downloaded a nice set of demo's and experiments for the ezkit.
> It  
> is at http://www.ece.rutgers.edu/~orfanidi/ezkitl/ezkitl.html
> 
> Best regards,
> Ben



From ben at stuyts.nl  Wed Jan  6 10:30:02 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed,  6 Jan 99 10:30:02 +0100
Subject: Digital DIY synths?
In-Reply-To: <99010600424400.08380@Pandemonium>
References: <199901060030.BAA08018@daneel.stuyts.nl>
	<99010600424400.08380@Pandemonium>
Message-ID: <199901060930.KAA08288@daneel.stuyts.nl>

On Wed, 6 Jan 1999, Irish wrote:
> On Tue, 05 Jan 1999, Ben Stuyts typed:
> >On Tue, 5 Jan 1999, Troy Sheets wrote:
>
> >> I just think analog circuits
> >> have more "life" in them... they breathe and pulsate and you can hear
> >> the electrons squirting through your circuits.   Digital is just more
> >> sterile and mathmatic.
> >
> >There's just as much electrons in them DSP's... This sound like it could
> grow >out to an audiophile type of war. TUBES, USE TUBES! B-)
>
> Tubes? You use tubes? Why, there WAY too sterile and precise.
> Use Switches!  Lots of switches and knobs and relays! You can *definetly*
> feel the electrons in a setup like that! :P

Switches? You had switches? Man, we had to bang two rocks together to get any  
sound and use lightning for special effects. And we were grateful for it.

I feel a Monty Python thread coming up...

Best regards,
Ben



From john at nrtg.com  Wed Jan  6 10:41:11 1999
From: john at nrtg.com (John Tuffen)
Date: Wed, 6 Jan 1999 09:41:11 -0000
Subject: OT:  Roland Space Echo Schematic
Message-ID: <c=GB%a=_%p=NRTT%l=MARIUS_N-990106094111Z-9@pc130.nrtg.com>

As an aside, I think that I read this month in 'Sound On Sound' that
there is a company that is re-making tape loops for the space echo
devices..... I didn't pay too much attention as I don't have a space
echo!

john..


>-----Original Message-----
>
>> Parts are hard to get hold off. Roland UK don't have any pinch wheels in
>> stock , or any tape loops .
>



From urekar.m at EUnet.yu  Wed Jan  6 11:13:03 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Wed, 06 Jan 1999 11:13:03 +0100
Subject: 3904/3906 tranny specs
References: <00cb01be38fe$61d8cf40$6c5907c2@be053520>
Message-ID: <3693371E.2C91@eunet.yu>

perienced another nasty thing about trannies as a switch.
> The transistor was used in a voltage-shifter circuit and I had to connect a
> square-generator (about 1Hz) to it.
> I started the generator and left it alone for about half an hour.
> When I came back the tranny was broken.
> When I compared load-line and transistor-curve (ofcourse after the usual
> cursing and wishing all trannies to hell :-))it seems to be that the
> Vbe-capacitor (specific to every tranny) was the cause.
> The transistor has switched to slow (the cap slowed it down) between on and
> off-state, became hot and broke down...

if square goes negative more than 5 or 6 v directly to Vbe it can break
down
BE junction because of great inverse voltage
or you had too large collector current that fried(overheated) tranny


marjan



From zzynt at swipnet.se  Wed Jan  6 11:57:02 1999
From: zzynt at swipnet.se (BJ)
Date: Wed, 06 Jan 1999 02:57:02 -0800
Subject: The return of the V/F VCO!
References: <36924E13.31DF@ptdcs2.intel.com>
		<199901052131.WAA07866@daneel.stuyts.nl> <199901060037.BAA08027@daneel.stuyts.nl>
Message-ID: <3693417E.5003@swipnet.se>

Has any one done any test and considerations 
about using the TC9400 series V/F 14PIN DIP as a VCO?

The device has exelent data 0,05% linearity,0-100kHz,
and its outputs saw wave, and suare wave without any
external OP amps!

The IC is a form of a discreete integrator,comparator
saw VCO type in a 14 pin package!!

A couple of years back i wanted to try this one out
but eventually the IC was to expencive here so it went onto the ice.

BJ



From magnus at analogue.org  Wed Jan  6 12:30:29 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 06 Jan 1999 12:30:29 +0100
Subject: Digital DIY synths?
In-Reply-To: Your message of "Wed,  6 Jan 99 01:30:08 +0100"
References: <199901060030.BAA08018@daneel.stuyts.nl>
Message-ID: <199901061130.MAA03117@mail2.it.kth.se>

>>>>> "BS" == Ben Stuyts <ben at stuyts.nl> writes:

 BS> On Tue, 5 Jan 1999, Troy Sheets wrote:
 >> Plus, working on analog circuits is just more of an art.  There
 >> are so many more variables... Simple things like how well you have
 >> matched a transistor pair have subtle influences on the sound
 >> quality... how hard you drive your filter, ect.

 BS> Isn't it also the fun in designing a dsp based synth to make these things  
 BS> matter? To introdoce non-perfect saw pulses, to introduce non-linear  
 BS> transmission? I agree that a pure analog synth is more 'visible', but as I  
 BS> said in another message, I think it is just a matter of state of mind. In a  
 BS> dsp based synth, you are not trying to make the perfect mathematical pulse  
 BS> signal. That would be easy. You are trying to make the most musically pleasing  
 BS> pulse signal.

DSPs form another set of challanges, so do they really attract the
same people?

 >> It is these
 >> little details that make your own analog synth a real unique
 >> artistic tool.  Plus, I don't know... I just think analog circuits
 >> have more "life" in them... they breathe and pulsate and you can hear
 >> the electrons squirting through your circuits.   Digital is just more
 >> sterile and mathmatic.

 BS> There's just as much electrons in them DSP's... This sound like it could grow  
 BS> out to an audiophile type of war. TUBES, USE TUBES! B-)

Sure. Op-amps comes in tubes, DSPs come on tape or on charts ;^)

Cheers,
Magnus



From zzynt at swipnet.se  Wed Jan  6 12:30:32 1999
From: zzynt at swipnet.se (BJ)
Date: Wed, 06 Jan 1999 03:30:32 -0800
Subject: Digital DIY synths?
References: <199901050147.RAA28946@amy7.Stanford.EDU> <199901060004.BAA07994@daneel.stuyts.nl>
Message-ID: <36934958.1F69@swipnet.se>

Ben Stuyts wrote:

> One other thing that I'm missing from pure analog synths is the fact that you
> can only record the end product, the output wave. You cannot record your
> performance in, for example, a midi sequencer. I recently got interested again
> in analog synths, and thought I'd buy a paia fatman kit. Then I looked at the
> Waldorf Pulse, which is a DSP based analog modeling synth, where they used
> the fact that all controls are available (in and out) through midi. I thought

Well, the Pulse is not an modelling synth,its an odinary "old design"
Hybrid machine
usin two 68HC11's, one are used as inhouse doing the panel scanning,
midi, etc,
and the other 68HC11 as a DCO, generating three OSC's.
Besides that there is a analogue OTA LPF filter and VCA with pan.

If you listen carefully to it you can even hear the tech used in the
Pulse.

BJ



From zzynt at swipnet.se  Wed Jan  6 12:30:45 1999
From: zzynt at swipnet.se (BJ)
Date: Wed, 06 Jan 1999 03:30:45 -0800
Subject: Digital DIY synths?
References: <ISSMTP.1.3(1).19990104164120.4294106303B@Corp.wdc.com> <199901060004.BAA07991@daneel.stuyts.nl>
Message-ID: <36934965.1B58@swipnet.se>

Ben Stuyts wrote:
> 
> On Mon, 4 Jan 1999, Barry L Klein wrote:
> 
> > I received the same kit after attending one of AD's seminars.  Do these
> > other synths you mention use this same 2181 chip?
> 
> They use all kinds of chips. I think the Nord's and/or Acces Virus use
> multiple Moto 563xx parts. My Zoom 1504 effect processes uses a TI TMS320
> derivative, 

Do you know exactly wich one used TMS320c5xx series??
Iiiiih i have to open upp my ZOOM 1202 to see whats in it!!

>and it can do pitch shifting, vocoding, plus the usual assorti of
> delays. I don't know of any synth that uses the 2181, but I happened to get my
> hands on the eval kit. That's why I was interested in using it for music.

The Novation Drumstation uses a 2181/83 DSP for the percussion
emulation.
And some people say that the new Superstation uses the same DSP but a
bounch
of them!!
Hmm, would be more apropriate to use a Sharc instead!
 
> >  At the seminar they
> > demo'd a SHARC-based synth, which is a much more powerful chip, but it
> > sounded pretty cheasy.
> 
> The demo 2181 board comes with a demo 'Stairway to heaven' song on a plucked
> guitar-like waveform. (Wayne's World?) It sounds pretty awful too.

Agree, sounded crap the karplus strong algorithm, lousy way to promote a
DSP.

> > I think most of us would love to hear of digital synth attempts.  I
> > haven't heard of any modular designs using that approach.
 
> The Nord Modular uses that approach, but it is commercial and very expensive.
> You draw patch leads on a winblows program. Cute.

uNerd is fairly cheap,approx 623USD!!Only four voices but patch 
compatible with the Nerd Modular.
 

BJ



From beszedes at cc.u-szeged.hu  Wed Jan  6 12:33:33 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Wed, 06 Jan 1999 12:33:33 +0100
Subject: [Fwd: Re: quick question]
Message-ID: <36934A0D.5332003@cc.u-szeged.hu>



-------- Original Message --------
Subject: Re: quick question
Date: Tue, 05 Jan 1999 12:09:28 +0000
From: Peter Blackett <dragonser at clara.net>
Organization: Dragon servicing
To: Beszedes Arpad <beszedes at cc.u-szeged.hu>
References: <Pine.OSF.3.95.990104165956.26825A-100000 at is8.nyu.edu>
<3691C563.5B745F57 at cc.u-szeged.hu>

Hi,
it from the moog modular service manual ,at the synth diy site.
regards Peter 
South London England



From magnus at analogue.org  Wed Jan  6 12:43:13 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 06 Jan 1999 12:43:13 +0100
Subject: (OT)Re: Digital DIY synths?
In-Reply-To: Your message of "Wed, 6 Jan 1999 00:36:20 -0800"
References: <99010600424400.08380@Pandemonium>
Message-ID: <199901061143.MAA03169@mail2.it.kth.se>

>>>>> "I" == Irish  <irish at eskimo.com> writes:

 I> On Tue, 05 Jan 1999, Ben Stuyts typed:
 >> On Tue, 5 Jan 1999, Troy Sheets wrote:

 >>> I just think analog circuits
 >>> have more "life" in them... they breathe and pulsate and you can hear
 >>> the electrons squirting through your circuits.   Digital is just more
 >>> sterile and mathmatic.
 >> 
 >> There's just as much electrons in them DSP's... This sound like it could grow  
 >> out to an audiophile type of war. TUBES, USE TUBES! B-)

 I> Tubes? You use tubes? Why, there WAY too sterile and precise. 
 I> Use Switches!  Lots of switches and knobs and relays! You can *definetly*
 I> feel the electrons in a setup like that! :P

Why emulate when you can do the real stuff?

While it is true that my private symphony orchestra takes up a wing in
my little chatau, I think there is a special warmth in there.

Cheers,
Magnus



From irish at eskimo.com  Wed Jan  6 12:51:06 1999
From: irish at eskimo.com (Irish)
Date: Wed, 6 Jan 1999 03:51:06 -0800
Subject: Kits n stuff
Message-ID: <99010604320608.08380@Pandemonium>

Alright, I've read for a couple of days now, and to be truthful a bunch of this
is over my head. 
Let me explain; I am (was) a GMP/MilSpec rated assembler. I can ID almost any
part made, interpret schematics and drawings, and perform amazing feats of art
in solder using a dizzying array of tools from $2.98 snips to $160,000 PnP
machines.  
What I am not is an engineer. I know what various components are and do, and
in a general way I know what happens when you put certain ones in a circuit
together. I can use a meter but not a scope. 

Now, what I'd like to do is learn some theory, specifically as it relates
to our mutual interest :) , but to start out it might help me to understand
what all these things (like LFOs, VCFs, filters, modulators, etc. ) DO
individually and when hooked together. To that end I would like to find some
kits. I've already ordered the MadMouse - looks like fun to make and use. I'd
also like to find some signal processing / effects type stuff. Ring Mod maybe,
or analog delay? Stuff that's a kit, but winds up being cool useable gear. I've
tried a few web searches, but come up empty. Any pointers folks? 

If I may, I'd also like to ask your patience if I come up with some
ridiculously simple sounding questions. For example, I want to build a Midi
Thru box. I have a very simple diagram (it's not rocket science...) that calls
for a 74LS14. I can get it at RS or a local distrib for under a buck, BUT it's
a 14 pin DIP and the diagram naturally just shows the symbols, not the pinout.
Where can I find pinout for this and other common-as-dirt ICs? Again, web
searches I made were fruitless. This really seems silly - these must be
referenced somewhere on the net! 

Thanks for your help, 
Irish



From ms6gpm at bath.ac.uk  Wed Jan  6 12:58:49 1999
From: ms6gpm at bath.ac.uk (Gez)
Date: Wed, 6 Jan 1999 11:58:49 +0000 (BST)
Subject: strobe lights and tempo
In-Reply-To: <781753dd.3658b9e9@aol.com>
Message-ID: <Pine.GSO.4.04.9901061156410.11554-100000@ss1.bath.ac.uk>



Would the same type of bpm calculation be used to provide an interface
whereby an audio signal is analysed and a midi clock signal of the
correct tempo put out? Could this be done or would big DSP be needed? 




On Sun, 22 Nov 1998 Aranakin at aol.com wrote:

> how does a strobe that flashes with the beat (like at a dance club) work?
> whatis the principal behind it and who would sell a kit that would allow you
> to build your own sound reponsive strobe light?
> anthony
> 




From james at newd.demon.co.uk  Wed Jan  6 13:36:14 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Wed, 06 Jan 1999 12:36:14 +0000
Subject: Digital DIY synths?
Message-ID: <1.5.4.32.19990106123614.006baab8@pop3.demon.co.uk>

>The problem is that 16 bit a/d and d/a are  
>still expensive. Maybe one of the audio codec's (e.g. AD1847 as used in pc's)  
>would fit. Or, for fun, one could test the whole idea with 8 bit a/d and d/a.  
>Makes the software much easier too.

Unless Microchip bring out a 16 bit PIC!

James.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk
-------------------------------------------------------------------------------




From james at newd.demon.co.uk  Wed Jan  6 13:36:16 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Wed, 06 Jan 1999 12:36:16 +0000
Subject: Day Jobs
Message-ID: <1.5.4.32.19990106123616.0067b2b8@pop3.demon.co.uk>

What are all of your 'Day Jobs'?

If you want to know about me.......

I am 14, and live in England. I have had a passion for electronics,
computers and music for as long as I can remember. I put two and two
together one day and realised that I could design amd make music electronic
products. My interest in synths came about whilst using my schools's Juno
106. (Mmmm, lovely!). To feed my hobby, I design web-sites, and am currently
working on a Synth / Musical Electronics page.

James Jackson.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk
-------------------------------------------------------------------------------




From james at newd.demon.co.uk  Wed Jan  6 13:36:17 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Wed, 06 Jan 1999 12:36:17 +0000
Subject: Digital Stuff
Message-ID: <1.5.4.32.19990106123617.00679460@pop3.demon.co.uk>

Hi,
        Can anybody point me towards some stuff of designing synths and
other musical stuff with DSPs. Can you reccomend and DSP evaluation kits,
that have the power to do that kind of thing, and have D/A converters
on-board (maybe even A/D as well), but also have documentation, and info on
how to program them (I have experience with PICs)

Thanks,
James Jackson.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk
-------------------------------------------------------------------------------




From uzs159 at uni-bonn.de  Wed Jan  6 14:21:37 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 06 Jan 1999 14:21:37 +0100
Subject: 3904/3906 tranny specs
In-Reply-To: <00cb01be38fe$61d8cf40$6c5907c2@be053520>
Message-ID: <3.0.5.32.19990106142137.0089b770@ibm.rhrz.uni-bonn.de>

At 23:31 05.01.99 +0100, you wrote:

>No, not really...
>But I've experienced another nasty thing about trannies as a switch.
>The transistor was used in a voltage-shifter circuit and I had to connect a
>square-generator (about 1Hz) to it.
>I started the generator and left it alone for about half an hour.
>When I came back the tranny was broken.
>When I compared load-line and transistor-curve (ofcourse after the usual
>cursing and wishing all trannies to hell :-))it seems to be that the
>Vbe-capacitor (specific to every tranny) was the cause.
>The transistor has switched to slow (the cap slowed it down) between on and
>off-state, became hot and broke down...
>
>Never got this problem before...
>
>Strange huh, any other explainations?

This problem might also lie in the reduced safe operation area of transistors,
that is you can't rely on the maximum power dissipation alone, and there is
a further restriction on the maximum current for a certain power. 

I doubt that you blew the tranny because of the miller cap, since even if
you draw substantial power for a few microseconds there is still almost a
second of no power dissipation.

One cure for such problems is to use small signal mosfets in such
applications, they come in TTL /CMOS compatible flavors (with thresholds of
1.5V or so),
and they reduce your driving circuitry since you can ommit the base
resistor, and these are free from second breakdown and reduced safe
operation area. 
(But watch out for problems arising out of the gate capacitance.)

Rene


             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From Chris.List at sc.siemens.com  Wed Jan  6 15:59:42 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 6 Jan 1999 09:59:42 -0500
Subject: Digital DIY synths?
Message-ID: <81A062BC5305D111A9D700805F06596801836C42@maildepo.sc.siemens.com>

> -----Original Message-----
> From:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Sent:	Tuesday, January 05, 1999 6:56 PM
> To:	Harvey Devoe Thornburg
> Subject:	Re: Digital DIY synths?
> 
> In contrast to a few of the replies here, I do not consider the whole
> 
> software thing more difficult or less arty than the hardware approach.
> I think  
> it is more a state of mind thing. I think one can just as well enjoy
> tweaking  
> a musical algorithm for sound quality (or lack of! B-)) and
> performance, as  
> one can enjoy tweaking R's and C's.
> Best regards,
> Ben
> 
	I firmly agree, and while I personally have stayed away from
DSP, and while there were a lot of negatively-biased to your original
post, I encourage and request more discussion on this topic here on this
list. "Analog" is not part of the synth-diy charter.

	OTOH, I'd like to mention my own big reason for staying away
from DSP, and it's purely a matter of practicality and laziness...
	...Everything I've made from scratch (about 20 or 30 modules
now) has been made on pad-per-hole "vectorboard". SMD components and
wide data buses are a pain in the ass on vectorboard. :)

	- CList



From budweiser at ozemail.com.au  Wed Jan  6 16:09:40 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Thu, 7 Jan 1999 01:39:40 +1030
Subject: strobe lights and tempo
Message-ID: <009701be3986$96de3b20$53d26ccb@ppp.ozemail.com.au>

An envelope follower tuned to the frequency required would work.
Say, working between10Hz and 60Hz, a bass drum "beat" could
be extracted and a gate signal produced at the output, and used
to trigger a strobe midi clock (via some form for DSP for midi).

<bUd>

>Would the same type of bpm calculation be used to provide an interface
>whereby an audio signal is analysed and a midi clock signal of the
>correct tempo put out? Could this be done or would big DSP be needed?
>
>
>
>
>On Sun, 22 Nov 1998 Aranakin at aol.com wrote:
>
>> how does a strobe that flashes with the beat (like at a dance club) work?
>> whatis the principal behind it and who would sell a kit that would allow
you
>> to build your own sound reponsive strobe light?
>> anthony
>>
>
>




From martink at cix.co.uk  Wed Jan  6 16:18:00 1999
From: martink at cix.co.uk (Martin J Keefe)
Date: Wed, 6 Jan 1999 15:18 +0000 (GMT)
Subject: Digital DIY synths?
In-Reply-To: <199901060004.BAA07994@daneel.stuyts.nl>
Message-ID: <memo.19990106151839.265A@martink.compulink.co.uk>

> I haven't seen any messages yet though.

It seems pretty quiet at the moment -- I haven't seen any messages since 
the 4th.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From james at newd.demon.co.uk  Wed Jan  6 16:53:45 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Wed, 06 Jan 1999 15:53:45 +0000
Subject: DSP Stuff
Message-ID: <1.5.4.32.19990106155345.00679fe4@pop3.demon.co.uk>

Hi,
        I've found what looks like a good development kit for DSP based
synths... It's the EZ-Kit Lite. It's got a 16 bit stereo audio codec, and it
runs a sharc DSP. Has anybody got one / used one for synth stuff?

James.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk
-------------------------------------------------------------------------------




From debus at cityweb.de  Wed Jan  6 17:46:48 1999
From: debus at cityweb.de (Ingo Debus)
Date: Wed, 06 Jan 1999 17:46:48 +0100
Subject: AW: VCO-1C #2
References: <yam7672.1544.118972152@mail.mindspring.com>
Message-ID: <36939376.2BEB@cityweb.de>

tomg wrote:
> This is (no offence...really) a pretty nutty idea. Having only 12/16
> CEM3340s in a poly they used a cpu to keep 'em almost in tune, some
> of the time, and those were Curtis chips.
> 
> -tg (I push my tune buttons all the time)

Did all commercial 3340-based polyphonic synths have that "autotune"
feature or were there some without?

I'm asking because in my selfmade poly synth (without autotune) nine of
the ten 3340s are pretty stable, after a warm up time of 20 minutes or
so. But one is drifting very much. I thought that one had gone bad, but
maybe I just had luck with the other nine?

Ingo





From debus at cityweb.de  Wed Jan  6 17:52:53 1999
From: debus at cityweb.de (Ingo Debus)
Date: Wed, 06 Jan 1999 17:52:53 +0100
Subject: voltage reg. Question
References: <C35556591D34D111BB5600805F1961B90BBEAF1F@RED-MSG-47>
Message-ID: <369394E3.4033@cityweb.de>

David Halliday (Volt Computer) wrote:
> There was a shorted tantalum cap on the main board and it caused the power
> supply to show the same symptoms you are seeing.
[...]
> My technique for isolating the bad cap was quick and dirty but effective - I
> used an Xacto knife to cut the power traces until there was no short across
> the power in.  Once I had the section of the circuit isolated, I started
> unsoldering one leg of each capacitor I found, checking and resoldering it
> until I found the bad one.

Sometimes you can see if a tantalum cap has gone bad: there's a tiny
silver ball on it, looks like a tiny splash of solder.

Ingo




From halmans at globalxs.nl  Wed Jan  6 18:13:40 1999
From: halmans at globalxs.nl (Maarten Halmans)
Date: Wed, 06 Jan 1999 18:13:40 +0100
Subject: components in the Netherlands
Message-ID: <369399C4.F6BEFE0E@globalxs.nl>

Hi,

I am looking for a component supplier in the Netherlands. I usually buy
my components at Display, but they are expensive and their assortment is
very limited. I have been looking for  mail order businesses, but they
all demand that you are registered as a company. So I was wondering
where the dutch people on this list get their components.

Thanks,
Maarten





From chordman at flash.net  Wed Jan  6 18:40:05 1999
From: chordman at flash.net (Scott Gravenhorst)
Date: Wed, 06 Jan 99 18:40:05
Subject: Digital DIY synths? Somewhat diverging
Message-ID: <199901070242.UAA09467@echo.flash.net>

Digital methodology other than DSP can also be employed.  Such as Walsh
Function Generators.  I believe that someone else on this list has
experimented with Walsh.  I certainly would like to play with this.  I
have also mixed analog with digital for hybrid systems.  Some things
are very simple using digital, such as frequency division (flip flop
divide down) and multiplication (PLL at least).

-- Scott Gravenhorst
-- RedWebMail by RedStarWare (srg)
-- FatMan Site: www.teklab.com/~chordman
-- Linux Rex, Linux Vobiscum





From costello at seanet.com  Wed Jan  6 20:11:47 1999
From: costello at seanet.com (Sean Costello)
Date: Wed, 06 Jan 1999 11:11:47 -0800
Subject: AW: VCO-1C #2
References: <yam7672.1544.118972152@mail.mindspring.com> <36939376.2BEB@cityweb.de>
Message-ID: <3693B573.3F907EA2@seanet.com>

Ingo Debus wrote:

> Did all commercial 3340-based polyphonic synths have that "autotune"
> feature or were there some without?

I know a lot of them did.  I know that the Prophet 5 I once owned had
that feature.  If I am not mistaken, the original Memorymoog did not
have autotune, or had a very poor autotune.  Of course, people claim
today that the autotune function makes for a very sterile sound, and
that synths without autotune are "fatter."  Hey, if you don't like the
sound, don't push the autotune button!  

Sean Costello



From cyborg0 at GlobalEyes.net  Wed Jan  6 20:31:55 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Wed, 06 Jan 1999 13:31:55 -0600
Subject: DSP Stuff
References: <1.5.4.32.19990106155345.00679fe4@pop3.demon.co.uk>
Message-ID: <3693BA2B.9DE5D5E9@globaleyes.net>

James Jackson wrote:
> 
> Hi,
>         I've found what looks like a good development kit for DSP based
> synths... It's the EZ-Kit Lite. It's got a 16 bit stereo audio codec, and it
> runs a sharc DSP. Has anybody got one / used one for synth stuff?
> 
> James.

Nope.. this is also the misconception I had.. its not actually a SHARC..
The devkit for the SHARC is about  1k dollars... Although, the ezkit
lite is very cool, you could build a drumstation with it..it uses the
2181. Not too shabby..

I have wanted to get one, but that means pretty much that I would have
to take calculus for the third time to understand how to program it...
I cant do calc worth a crap... Although i can understand it well enough
that i tutored ppl who were getting 100 percent on tests I could barely
get 70 percent on.. :( I can recite theorems verbatim, but can't keep
track of the steps and signs.
I guess I can always start the whole sequence again from basic math
2+2=4 like my counselor suggested.. *sniff*

This whole business is what scares the hell out of me and makes me avoid
DSP like the plague. Although I wish I had the time to learn it and the
math behind it.

Rob
I am the infamous sign dropper youve heard so much about..



From guidogoe at xs4all.nl  Wed Jan  6 22:35:42 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Wed, 06 Jan 1999 21:35:42 GMT
Subject: Kits n stuff
Message-ID: <915655118-333337AEicMi@xs4all.nl>

>Irish wrote:

>Now, what I'd like to do is learn some theory, especicically as it relates to our mutual interest :),but to start out it might help me to understand what all these things (like LFOs, VCFs, filters, modulators, etc.) DO individually and when hooked together.

All of this synth. building blocks are dealing with CONTROL VOLTAGES.
For example: a LFO (Low Frequency Oscillator) ,usually with sine/triangle/square-wave output is able to modulate a VCO (Voltage Controlled Oscillator) or a VCF (Voltage Controlled Filter).
A VCO is the unit which produces the sound you can hear when you play a keyboard. It has a sound output with different harmonical content. (e.g. different timbres/waveforms).

When you modulate a VCO with an LFO's SINEWAVE you'll get a vibrato effect by low depht settings, and a siren effect by deep settings.
A TRIANGLE will produce simulair effects, a SQUARE wave is much more choppy and radical, but all of these effects are pitch related.

The same thing goes when you modulate a VCF with an LFO waveform: you'll get periodical changes in timbre depending on the LFO waveform you use and the speed of the LFO.
In general: Deep modulation settings provide more radical changes in the resulting sound. But all of this will be timbre related.

ADSR generators are also controllers, they control the shape of the resulting sound, assignable to VCF (timbre), VCO (pitch) and VCA (volume).

ADSR stands for: Attack/Decay/Sustain/Release (Envelop Generator).
Supllied to a VCA (Voltage Controlled Amplifier) it controlles the range between (fast attack) piano or string (slow attack) like sounds. So this one is volume related (contour).
But supplied to a VCO it will be pitch related, and to a VCF timbre related.

So, in short: LFO's and ADSR's and the like are controllers and blocks like VCO's and VCF are receiving that info and become controlled.

In general, you should experiment with this, that is if you own an (analog) synth, you do, don't you???

Guido /THD Studio




From DinedHavoC at aol.com  Wed Jan  6 23:51:56 1999
From: DinedHavoC at aol.com (DinedHavoC at aol.com)
Date: Wed, 6 Jan 1999 17:51:56 EST
Subject: Kits n stuff
Message-ID: <343c8448.3693e90c@aol.com>

In a message dated 1/6/99 4:28:49 PM Central Standard Time, guidogoe at xs4all.nl
writes:

<< In general, you should experiment with this, that is if you own an (analog)
synth, you do, don't you???
 
 Guido /THD Studio >>

Im almost sure that Irish here doesnt own an analog synth, but if u decide to
get one Irish, then id like to make some suggestions.
The Sequential Circuits Pro One is an analog synth, 2 oscillators, one VCF
(voltage controlled filter) with ADSR, one VCA (VOltage controller amplifier),
a 40 step sequencer, an arpeggiator with two patterns, glide control, and an
LFO.  I suggest it  as a great first analog as it is your basic "ordinary"
analog synth.  ofcourse, the sound is not ordinary by most standards, u get
your basic analog sounds (the sounds u hear in a lot of electronic music these
days, or "techno" as some call it), plus a few wild things unique to the Pro
One that are hard to explain. 
A few things u have to understand when making an analog synth purchase:
1.  They are unstable.  You have to tune them often.
2.  To much heat (above room temp) is BAD for an analog synth.
3.  You have to buy most of them used, as most are out of production except a
chosen few (Pulse, ATC1, etc.).
4.  You dont get ANY MIDI unless you retrofit it which costs $$$$$ squared!!!
Ofcourse you always have control voltage outputs, which i think r a lot cooler
( ;
5.  Because most analog synths stopped production around the early eighties,
its quite a task to find one in perfect working order.  Much less mostly
working order.
6.  Most analogs are MONOPHONIC. This means one note at a time!

I suggest you get an analog in decent shape, and explore the VCOs, VCAs, LFOs,
and VCFs... get to know them.
Heres some links to get ya going...
http://www.sonicstate.com/synth/test.html  -  Synthsite. User reviews of
synths. Check out the Moog Minimoog review, its a great review.

www.dancetech.com  -  Dancetech. some ok reviews here.

http://www.synthmuseum.com/dir.html  -  Synth Museum. I LUV this site.

http://www.pacificnet.net/~hypno/  -  Vintage Synth Explorer. Not bad.

heres some Synth DIY links for ya:
http://metro.net/blacet/music.html  -  Blacet Research, home of the Dark Star
and Klangwerk.

http://www.tomg.vivid.net/  -  Tom G kits.  Good stuff.

http://www.synthtech.com/  -  Synth Tech.  Paul makes some neato keen modules.

Sorry for the bandwidth,
~Dave~



From ben at stuyts.nl  Thu Jan  7 00:09:14 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 00:09:14 +0100
Subject: components in the Netherlands
In-Reply-To: <369399C4.F6BEFE0E@globalxs.nl>
References: <369399C4.F6BEFE0E@globalxs.nl>
Message-ID: <199901062309.AAA08688@daneel.stuyts.nl>

(I'll keep it in English in case other people on the list are interested.)

On Wed, 06 Jan 1999, Maarten Halmans wrote:

> I am looking for a component supplier in the Netherlands. I usually buy
> my components at Display, but they are expensive and their assortment is
> very limited. I have been looking for  mail order businesses, but they
> all demand that you are registered as a company. So I was wondering
> where the dutch people on this list get their components.

Have you checked RS components in Haarlem? (phone 023 5166555, and they have  
a web site which I can't locate right now.) They do mail order, but I'm not  
sure about delivery to individuals. They are also expensive, but their have a  
broader range of components.

Anyway, what kind of components are you looking for? My company has access to  
all the electronics distributors in NL.

Best regards,
Ben



From magnus at analogue.org  Thu Jan  7 00:21:06 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 07 Jan 1999 00:21:06 +0100
Subject: BJ's 4046 oscillator
Message-ID: <199901062321.AAA07024@mail2.it.kth.se>

Hi!

It just truck me that there is more to BJs 4046 oscillator.

>From the two buffer op-amps comes two waveforms that look like this


0 V -   ---   ---   ---   ---
     \  |  \  |  \  |  \  |  
      \ |   \ |   \ |   \ |  
       \|    \|    \|    \|  

0V   ---   ---   ---   ---   -
     |  \  |  \  |  \  |  \  |
     |   \ |   \ |   \ |   \ |
    \|    \|    \|    \|    \|

Adding them creates a saw, but subtracting them and you got yourself a
triangle. Using the saw+square trick you can have a sawtooth of the
same frequency as the triangle, and they are in phase. A deglitching
is assumed ofcourse.

Cheers,
Magnus



From ben at stuyts.nl  Thu Jan  7 00:26:03 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 00:26:03 +0100
Subject: Kits n stuff
In-Reply-To: <99010604320608.08380@Pandemonium>
References: <99010604320608.08380@Pandemonium>
Message-ID: <199901062326.AAA08700@daneel.stuyts.nl>

On Wed, 6 Jan 1999, Irish wrote:

> To that end I would like to find some
> kits.

Have you looked at http://www.paia.com ? They have the FatMan synth. It is  
similar to the MadMouse. The Paia site is a nice site to browse anyway.

> calls for a 74LS14. I can get it at RS or a local distrib for under a buck,
> BUT it's a 14 pin DIP and the diagram naturally just shows the symbols, not
> the pinout. Where can I find pinout for this and other common-as-dirt ICs?

You could get the RS CDROM. It has many data sheets on it.

There are some site which have lists of the most common ICs. For example:  
http://www.falstaff.demon.co.uk/giicm.html (the Giant Internet IC  
Masturbator). There's also http://www.repairfaq.org/filipg/ which might  
interest you. It looks very repair-oriented, but there's some good stuff  
there.

> Again, web searches I made were fruitless. This really seems silly - these
> must be referenced somewhere on the net!

You might also want to have a look at some newsgroups. comp.arch.hobbyist or  
the various sci.electronics.design, sci.electronics.misc, etc. Also, the  
people on this list have been posting interesting web pages, which sometimes  
contain more links than mortals can follow. B-)

Best regards,
Ben



From ben at stuyts.nl  Thu Jan  7 00:51:35 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 00:51:35 +0100
Subject: Digital DIY synths?
In-Reply-To: <36934958.1F69@swipnet.se>
References: <199901050147.RAA28946@amy7.Stanford.EDU>
	<199901060004.BAA07994@daneel.stuyts.nl> <36934958.1F69@swipnet.se>
Message-ID: <199901062351.AAA08723@daneel.stuyts.nl>

On Wed, 06 Jan 1999, BJ wrote:

> Well, the Pulse is not an modelling synth,its an odinary "old design"
> Hybrid machine
> usin two 68HC11's, one are used as inhouse doing the panel scanning,
> midi, etc,
> and the other 68HC11 as a DCO, generating three OSC's.
> Besides that there is a analogue OTA LPF filter and VCA with pan.

Aha, I was misinformed then. Thanks for the info. Do you have some more  
information about it? Or have you opened one up? Schematics? B-)

Best regards,
Ben



From ben at stuyts.nl  Thu Jan  7 01:00:08 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 01:00:08 +0100
Subject: Digital DIY synths?
In-Reply-To: <36934965.1B58@swipnet.se>
References: <ISSMTP.1.3(1).19990104164120.4294106303B@Corp.wdc.com>
	<199901060004.BAA07991@daneel.stuyts.nl> <36934965.1B58@swipnet.se>
Message-ID: <199901070000.BAA08730@daneel.stuyts.nl>

On Wed, 06 Jan 1999, BJ wrote:

> > They use all kinds of chips. I think the Nord's and/or Acces Virus use
> > multiple Moto 563xx parts. My Zoom 1504 effect processes uses a TI TMS320
> > derivative,
>
> Do you know exactly wich one used TMS320c5xx series??
> Iiiiih i have to open upp my ZOOM 1202 to see whats in it!!

I don't know. I just had a cursory look at it when I took it apart to paint  
the back of the case black. (I don;t have it in a 19" rack, so the bare metal  
color was annoying me.)

> The Novation Drumstation uses a 2181/83 DSP for the percussion
> emulation.
> And some people say that the new Superstation uses the same DSP but a
> bounch
> of them!!
> Hmm, would be more apropriate to use a Sharc instead!

Well, we've done some designs where the availability of tools (compilers,  
debuggers, emulators, existing source code) played a bigger part than the cost  
or neatness of the solution. It is all a matter of economics.

>From what I have seen, it is indeed better to use a Sharc or any other  
floating point DSP. It makes the software probably simpler. The AD 2818  
doesn't have a large dynamic range. For example, the Moto 56xxx range has a 56  
bit intermediate accumulator, so although it is fixed point, it has better  
range.

Best regards,
Ben
 



From ben at stuyts.nl  Thu Jan  7 01:10:15 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 01:10:15 +0100
Subject: Digital DIY synths?
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D6851@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6851@demon>
Message-ID: <199901070010.BAA08746@daneel.stuyts.nl>

On Wed, 6 Jan 1999, Roman Sowa wrote:

> it will not run on ezkitlite - it requires some additional hardware,
> but first prototype was made around ezkitlite itself (+5 or 6 ICs)

So you probably use the parallel dma port to download code?

> what I did'nt like? slow downloads, noisy codec and it's way of
> programming, poor RS232 link, sometimes I couldn't download
> new program into DSP without reseting the board.
> And the PC software had like *no* features.
> But maybe it was just my unit - I bought it in 1995 (?)

Sounds similar to the latest release.

Best regards,
Ben



From ben at stuyts.nl  Thu Jan  7 01:18:53 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 01:18:53 +0100
Subject: Digital DIY synths?
In-Reply-To: <81A062BC5305D111A9D700805F06596801836C42@maildepo.sc.siemens.com>
References: <81A062BC5305D111A9D700805F06596801836C42@maildepo.sc.siemens.com>
Message-ID: <199901070024.BAA08759@daneel.stuyts.nl>

On Wed, 6 Jan 1999, "List, Christopher" wrote:

> OTOH, I'd like to mention my own big reason for staying away
> from DSP, and it's purely a matter of practicality and laziness...
> ...Everything I've made from scratch (about 20 or 30 modules
> now) has been made on pad-per-hole "vectorboard". SMD components and
> wide data buses are a pain in the ass on vectorboard. :)

I can imagine that. That is why those ready made evaluation boards are so  
neat. They usually offer an audio-grade a/d and d/a, and some development  
software for use on a pc, so it is plug and go. Motorola, Texas Instruments  
and Analog Devices offer them, plus probably some other chip mfgrs too. And  
there's lots of demo code to get you started.

And in any case, you could play with digital synthesis on a simple PC with a  
sound card. Although that doesn't really appeal to me. B-)
CSound is a good example of the latter, although it goes much further than  
only sound synthesis. (http://www.leeds.ac.uk/music/Man/c_front.html)

Best regards,
Ben



From ben at stuyts.nl  Thu Jan  7 01:23:28 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 01:23:28 +0100
Subject: Digital Stuff
In-Reply-To: <1.5.4.32.19990106123617.00679460@pop3.demon.co.uk>
References: <1.5.4.32.19990106123617.00679460@pop3.demon.co.uk>
Message-ID: <199901070024.BAA08762@daneel.stuyts.nl>

On Wed, 06 Jan 1999, James Jackson wrote:

> Can anybody point me towards some stuff of designing synths and
> other musical stuff with DSPs. Can you reccomend and DSP evaluation kits,
> that have the power to do that kind of thing, and have D/A converters
> on-board (maybe even A/D as well), but also have documentation, and info on
> how to program them (I have experience with PICs)

I have an Analog Devices EZKIT-lite. It has the ADSP2181 on board including  
the (stereo) a/d and d/a converters. But you might look at a kit from motorola  
with a 563xx dsp on it. These 56k DSP's are quite good for sound  
applications. I have one in my NeXT computer, and there are quite a few neat  
music applications for it.

Also, thanks to the recent hint on this list about the music-dsp mailing  
list, I found the music-dsp web site quite informative:  
http://shoko.calarts.edu/~glmrboy/musicdsp/music-dsp.html

It has many links to music dsp related items.

Best regards,
Ben



From ben at stuyts.nl  Thu Jan  7 01:28:51 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 01:28:51 +0100
Subject: DSP Stuff
In-Reply-To: <1.5.4.32.19990106155345.00679fe4@pop3.demon.co.uk>
References: <1.5.4.32.19990106155345.00679fe4@pop3.demon.co.uk>
Message-ID: <199901070028.BAA08767@daneel.stuyts.nl>

On Wed, 06 Jan 1999, James Jackson wrote:

> I've found what looks like a good development kit for DSP based
> synths... It's the EZ-Kit Lite. It's got a 16 bit stereo audio codec, and it
> runs a sharc DSP. Has anybody got one / used one for synth stuff?

Beware, there are two EZ-Kit's: one with the ADSP2181, which is about $100.  
This is a fixed point DSP. Then there's another one with the floating point  
Sharc DSP, but it is more expensive. The floating point capabilities should  
make it easier to program, but I have no experience with that.

I have the 2181 kit, and it works, although I think it is a bit noisy. (Bad  
pcb layout?) It comes with an assembler and some demo programs, and it is easy  
to program (if you have some experience in assembler). I recently found a web  
site (http://www.ece.rutgers.edu/~orfanidi/ezkitl/ezkitl.html) with some  
additional lab excercises for the EZKIT.

Best regards,
Ben



From zzynt at swipnet.se  Thu Jan  7 01:53:12 1999
From: zzynt at swipnet.se (BJ)
Date: Wed, 06 Jan 1999 16:53:12 -0800
Subject: OT:  Roland Space Echo Schematic,
References: <19990106033303.AAA16959@mail01.t-net.net.ve@arturomi>
Message-ID: <36940578.7E92@swipnet.se>

Arturo Mieussens wrote:

> Dealing with the venezuelan distrubutor is anything but a pleasure, they
> refuse to do any servicing to equipment bought anywhere else. They once
> refused to get me an LCD screen for an XP-10 I bought in a trip to the
> states. I don't know what Roland would think of their behaviour but I have
> though of writing them about it.

Dealing with anything in venezuela is everyting but a pleasure!!
I know, i have spent four months in venezuela and the caribbean!!

The Guarda Nacional steel my backpack at the last military stop at the
gran sabana,south american highway when i was going to Santa Helena de
uarien!!

Ass hole people,thats costed me 16000 bolivares, and when i was going to
take a cab back to the military outpost to try to pick up my backpack
two military ass holes "just" jumped in to the cab to have a free ride 
back to their asshole outpost!!!

Just wanted to mention this since this MP people use to take peoples
packings
and put drugs in them just so they can black mail them to handle over
some
"""green bills"" .Just remember that the venuzulano prisons are the
worst on the 
planet. A common saying is, "no one lasts more then two years in our
prisons" 

Do not belive that one can travel around in venezuela just speking
english, spanish is necessary,otherwise one are just regarded as a 
""walking bank.""

Besides the hassle o stress by the MP or any other police the 
country is wery interesting and has a loot to offer the traveller! 

> So if anybody could  scan or sell me a copy I would be gratefull.

Can for sure understand your conserns!

One solution for you (if you live there or close near by)is to order
everything you need from the outside world to one of the internattional
package delivery companieses(DHL, feedex etc) office at Isla Margarita
Its a tax free zone and gods deliverys are taken several times each day
from Miami, Orlando etc, Florida.
To make this smooth(fairly smooth)you need a VISA card. 

BJ



From budweiser at ozemail.com.au  Thu Jan  7 04:47:18 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Thu, 7 Jan 1999 14:17:18 +1030
Subject: Digital DIY synths?
Message-ID: <012801be39f0$6d9d1d20$53d26ccb@ppp.ozemail.com.au>


-----Original Message-----
From: Arthur Harrison <theremin1 at worldnet.att.net>
To: DIY <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 2:10 PM
Subject: Re: Digital DIY synths?


>
>-----Original Message-----
>From: Ben Stuyts <ben at stuyts.nl>
>To: irish at eskimo.com <irish at eskimo.com>
>Cc: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
>Date: Wednesday, January 06, 1999 3:48 AM
>Subject: Re: Digital DIY synths?
>
>
>>On Wed, 6 Jan 1999, Irish wrote:
>>> On Tue, 05 Jan 1999, Ben Stuyts typed:
>>> >On Tue, 5 Jan 1999, Troy Sheets wrote:
>>>
>>> >> I just think analog circuits
>>> >> have more "life" in them... they breathe and pulsate and you can hear
>>> >> the electrons squirting through your circuits.   Digital is just more
>>> >> sterile and mathmatic.
>>> >
>>> >There's just as much electrons in them DSP's... This sound like it
could
>>> grow >out to an audiophile type of war. TUBES, USE TUBES! B-)
>>>
>>> Tubes? You use tubes? Why, there WAY too sterile and precise.
>>> Use Switches!  Lots of switches and knobs and relays! You can
*definetly*
>>> feel the electrons in a setup like that! :P
>>
>>Switches? You had switches? Man, we had to bang two rocks together to get
>any
>>sound and use lightning for special effects. And we were grateful for it.
>
>Well, you guys just don't know how bad things can be until you try building
>an amplifier from nothing more than a neon lamp and some ordinary carbon
>rods!
>



I wish some of you would get a life....like join my life long hobby of
trying
to get a Gameboy to run Windows NT.... and network it to a c64, and Sun
Sparc....


<bUd>  is having a party




From idreamin3d at toad.net  Thu Jan  7 05:39:36 1999
From: idreamin3d at toad.net (I Dream In 3D)
Date: Wed, 06 Jan 1999 23:39:36 -0500
Subject: Digital DIY synths?
In-Reply-To: <012801be39f0$6d9d1d20$53d26ccb@ppp.ozemail.com.au>
Message-ID: <3.0.1.32.19990106233936.006cf038@toad.net>

At 02:17 PM 1/7/99 +1030, Budweiser [FTS] wrote:
>
>-----Original Message-----
>From: Arthur Harrison <theremin1 at worldnet.att.net>
>To: DIY <synth-diy at mailhost.bpa.nl>
>Date: Thursday, January 07, 1999 2:10 PM
>Subject: Re: Digital DIY synths?
>
>
>>
>>-----Original Message-----
>>From: Ben Stuyts <ben at stuyts.nl>
>>To: irish at eskimo.com <irish at eskimo.com>
>>Cc: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
>>Date: Wednesday, January 06, 1999 3:48 AM
>>Subject: Re: Digital DIY synths?
>>
>>
>>>On Wed, 6 Jan 1999, Irish wrote:
>>>> On Tue, 05 Jan 1999, Ben Stuyts typed:
>>>> >On Tue, 5 Jan 1999, Troy Sheets wrote:
>>>>
>>>> >> I just think analog circuits
>>>> >> have more "life" in them... they breathe and pulsate and you can hear
>>>> >> the electrons squirting through your circuits.   Digital is just more
>>>> >> sterile and mathmatic.
>>>> >
>>>> >There's just as much electrons in them DSP's... This sound like it
>could
>>>> grow >out to an audiophile type of war. TUBES, USE TUBES! B-)
>>>>
>>>> Tubes? You use tubes? Why, there WAY too sterile and precise.
>>>> Use Switches!  Lots of switches and knobs and relays! You can
>*definetly*
>>>> feel the electrons in a setup like that! :P
>>>
>>>Switches? You had switches? Man, we had to bang two rocks together to get
>>any
>>>sound and use lightning for special effects. And we were grateful for it.
>>
>>Well, you guys just don't know how bad things can be until you try building
>>an amplifier from nothing more than a neon lamp and some ordinary carbon
>>rods!
>>
>
>
>
>I wish some of you would get a life....like join my life long hobby of
>trying
>to get a Gameboy to run Windows NT.... and network it to a c64, and Sun
>Sparc....
>
>
><bUd>  is having a party
>
>

I wrote a graphical WWW browser for the C64 about two years ago.  It was
painfully slow (took about an hour to view a page which was mostly text.)
and would crash whenever you ran into a script or JAVA, but it was still
cool.....well, atleast I thought it was.

Jason McMahon
experimental musician/electrician
i break things on purpose




From mwmjr at ix.netcom.com  Thu Jan  7 05:46:40 1999
From: mwmjr at ix.netcom.com (Michael Maloney)
Date: Wed, 06 Jan 1999 23:46:40 -0500
Subject: DSP Stuff
Message-ID: <3.0.5.32.19990106234640.007cab40@popd.ix.netcom.com>

>Beware, there are two EZ-Kit's: one with the ADSP2181, which is about $100.  
>This is a fixed point DSP. Then there's another one with the floating point  
>Sharc DSP, but it is more expensive. The floating point capabilities should  
>make it easier to program, but I have no experience with that.
>
Obviously the floating point stuff allows you to skip a few steps (e.g.
re-scaling), but the 21061 ezkit lite also comes with a "light" version of
the G21K C compiler...as I recall it was about $300.00.  I'm ashamed to say
that mine is still in the box, so I can't comment on its noise levels.

Mike Maloney



From theremin1 at worldnet.att.net  Thu Jan  7 06:07:01 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 6 Jan 1999 21:07:01 -0800
Subject: Digital DIY synths?
Message-ID: <004101be39fb$8ff18fe0$d642440c@hpcustomer>


-----Original Message-----
From: Ben Stuyts <ben at stuyts.nl>
To: irish at eskimo.com <irish at eskimo.com>
Cc: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Wednesday, January 06, 1999 3:48 AM
Subject: Re: Digital DIY synths?


>On Wed, 6 Jan 1999, Irish wrote:
>> On Tue, 05 Jan 1999, Ben Stuyts typed:
>> >On Tue, 5 Jan 1999, Troy Sheets wrote:
>>
>> >> I just think analog circuits
>> >> have more "life" in them... they breathe and pulsate and you can hear
>> >> the electrons squirting through your circuits.   Digital is just more
>> >> sterile and mathmatic.
>> >
>> >There's just as much electrons in them DSP's... This sound like it could
>> grow >out to an audiophile type of war. TUBES, USE TUBES! B-)
>>
>> Tubes? You use tubes? Why, there WAY too sterile and precise.
>> Use Switches!  Lots of switches and knobs and relays! You can *definetly*
>> feel the electrons in a setup like that! :P
>
>Switches? You had switches? Man, we had to bang two rocks together to get
any
>sound and use lightning for special effects. And we were grateful for it.

Well, you guys just don't know how bad things can be until you try building
an amplifier from nothing more than a neon lamp and some ordinary carbon
rods!

-Art





From harv23 at leland.Stanford.EDU  Thu Jan  7 06:14:15 1999
From: harv23 at leland.Stanford.EDU (Harvey Devoe Thornburg)
Date: Wed, 6 Jan 1999 21:14:15 -0800 (PST)
Subject: Digital DIY synths? Somewhat diverging
In-Reply-To: <199901070242.UAA09467@echo.flash.net> from "Scott Gravenhorst" at Jan 6, 99 06:40:05 pm
Message-ID: <199901070514.VAA16944@saga0.Stanford.EDU>

> 
> Digital methodology other than DSP can also be employed.  Such as Walsh
> Function Generators.  I believe that someone else on this list has
> experimented with Walsh. 

Walsh is kind of a DSP technique, just not a linear one.
You can do nonlinear filtering with Walsh functions
as well as function generation.

Some time ago I experimented with the Walsh-Hadamard transform
for image processing, which projects the image onto a set of
Walsh functions rather than the standard Fourier (sine wave)
basis.  If you do a "lowpass filter" in the Walsh domain this
is the same as averaging blocks, which produces "blocky" images like 
when you don't want to show someone's face on TV.  Of course
this can be done just be averaging blocks, but other kinds of
filters (like bandpass) don't have so obvious results.  Because
of the implicit downsampling and stairstep interpolation, the 
Walsh lowpass has a lot of aliasing/imaging but they could be
useful for a variety of noise and percussion sounds. 
 
The cool thing about the Walsh-Hadamard transform is that 
it is all done with addition and subtraction, and it obeys 
a FFT recursion.  So it turns out to be fast and more suited
to real-time.

--Harvey

> have also mixed analog with digital for hybrid systems.  Some things
> are very simple using digital, such as frequency division (flip flop
> divide down) and multiplication (PLL at least).
> 
> -- Scott Gravenhorst
> -- RedWebMail by RedStarWare (srg)
> -- FatMan Site: www.teklab.com/~chordman
> -- Linux Rex, Linux Vobiscum
> 

 




From theremin1 at worldnet.att.net  Thu Jan  7 06:43:44 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 6 Jan 1999 21:43:44 -0800
Subject: Kits n stuff
Message-ID: <007001be3a00$b1907d00$d642440c@hpcustomer>

Irish,

If you have a .pdf reader on your machine, see:
http://www.fairchildsemi.com/ds/DM/DM74LS14.pdf
for a 'LS14 data sheet.

Also, you might want to register with:
http://www.questlink.com/
It is a really nice index of many IC manufacturers' data,
and it is free.

Let me know if this works for you.

-Art in thereminland


-----Original Message-----
From: Irish <irish at eskimo.com>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Wednesday, January 06, 1999 10:10 AM
Subject: Kits n stuff


>Alright, I've read for a couple of days now, and to be truthful a bunch of
this
>is over my head.
>Let me explain; I am (was) a GMP/MilSpec rated assembler. I can ID almost
any
>part made, interpret schematics and drawings, and perform amazing feats of
art
>in solder using a dizzying array of tools from $2.98 snips to $160,000 PnP
>machines.
>What I am not is an engineer. I know what various components are and do,
and
>in a general way I know what happens when you put certain ones in a circuit
>together. I can use a meter but not a scope.
>
>Now, what I'd like to do is learn some theory, specifically as it relates
>to our mutual interest :) , but to start out it might help me to understand
>what all these things (like LFOs, VCFs, filters, modulators, etc. ) DO
>individually and when hooked together. To that end I would like to find
some
>kits. I've already ordered the MadMouse - looks like fun to make and use.
I'd
>also like to find some signal processing / effects type stuff. Ring Mod
maybe,
>or analog delay? Stuff that's a kit, but winds up being cool useable gear.
I've
>tried a few web searches, but come up empty. Any pointers folks?
>
>If I may, I'd also like to ask your patience if I come up with some
>ridiculously simple sounding questions. For example, I want to build a Midi
>Thru box. I have a very simple diagram (it's not rocket science...) that
calls
>for a 74LS14. I can get it at RS or a local distrib for under a buck, BUT
it's
>a 14 pin DIP and the diagram naturally just shows the symbols, not the
pinout.
>Where can I find pinout for this and other common-as-dirt ICs? Again, web
>searches I made were fruitless. This really seems silly - these must be
>referenced somewhere on the net!
>
>Thanks for your help,
>Irish




From theremin1 at worldnet.att.net  Thu Jan  7 07:05:04 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 6 Jan 1999 22:05:04 -0800
Subject: components in the Netherlands
Message-ID: <009401be3a03$ac54bce0$d642440c@hpcustomer>

It was said:

>Have you checked RS components in Haarlem? (phone 023 5166555, and they
have
>a web site which I can't locate right now.)

I say:

Try:
http://www.worldserver.pipex.com/rs/
(A lot of folks here in the US think "RS" means Radio Shack, but they're two
different
companies.)

-Art





From harv23 at leland.Stanford.EDU  Thu Jan  7 07:30:39 1999
From: harv23 at leland.Stanford.EDU (Harvey Devoe Thornburg)
Date: Wed, 6 Jan 1999 22:30:39 -0800 (PST)
Subject: DSP Stuff
In-Reply-To: <3.0.5.32.19990106234640.007cab40@popd.ix.netcom.com> from "Michael Maloney" at Jan 6, 99 11:46:40 pm
Message-ID: <199901070630.WAA18549@saga0.Stanford.EDU>

> 
> >Beware, there are two EZ-Kit's: one with the ADSP2181, which is about $100.  
> >This is a fixed point DSP. Then there's another one with the floating point  
> >Sharc DSP, but it is more expensive. The floating point capabilities should  
> >make it easier to program, but I have no experience with that.
> >

Floating point is really the most natural for audio, because our 
perception of frequencies and amplitudes is logarithmic, and also 
because the most efficient attempts to simulate floating point
with long ints in fixed point instructions almost always generates 
unreadable code (reliance on shifts etc.) for ex. to divide by 255 
(common in graphics and image processing) on a fixed point 
machine it is easier use the 
relation 1/255 = 1/256 + 1/256^2 + 1/256^3 + ... and use shifts and
accumulates.  I have seen, but thankfully never had to write, this kind
of stuff in audio applications.  Do you really want to be thinking 
about this stuff (hint: the compiler never helps you) or thinking 
about the algorithm?

One thing might be disturbing with floating point is the generation 
of underflow errors. let's say you're using a one-pole filter for an 
envelope generator (like for a 303 model) and there's a long time 
between gates, then sooner or later you will underflow. 
some processors (Pentium) react very poorly to this, causing much 
slowdown (or maybe this is due to Microsoft DirectSound standard?)  

Traditionally the audio industry has used Motorola 56K's but many new
companies are transitioning to ADSP21061 or 21160 (600 mflops) sharc.
The main issue seems to be floating point, the availablity of
C development environments, and parallelization (hardware support
for multiprocessing stuff like semaphores). I think Digidesign still 
uses 56K (which isn't much consolation for the $$$$$ for protools systems)!
There is some effort underway to port Csound to the sharc but I am
not up on this.

Something which interests me is the TI stuff like TMS320C60 floating
point series.  Performance is supposed to be in excess of 1000 mflops.
But the evaluation kit costs $1500 not to mention 3rd party development
tools.  I've been considering it (just to be different and to work
with a more powerful machine) but I don't know many in industry who
are adopting TI.

--Harvey



From harv23 at leland.Stanford.EDU  Thu Jan  7 07:36:59 1999
From: harv23 at leland.Stanford.EDU (Harvey Devoe Thornburg)
Date: Wed, 6 Jan 1999 22:36:59 -0800 (PST)
Subject: Tracking bandpass filter
Message-ID: <199901070636.WAA18653@saga0.Stanford.EDU>

now for something analog...
has anybody seen or built something like this?

http://www.electronicdevelopment.com/mod3800.htm

a tracking bandpass filter, enabled to extract frequency 
information from audio inputs through several different modes 
(adaptive filter or PLL (?))

and it has automatic gain control... this would be really cool for 
feedback loops.

--Harvey



From varner at k-online.com  Thu Jan  7 08:52:30 1999
From: varner at k-online.com (Steve Varner)
Date: Wed, 06 Jan 1999 23:52:30 -0800
Subject: Vishay tempco info
Message-ID: <369467BC.30E222DF@k-online.com>

I recieved the following letter from a Vishay rep:

-------------------------------------------------------------

Steven:

In response to your inquiry regarding temperature-sensitive resistors
(old Tel Labs Q81):

The Ultronix division of Vishay, located here in Malvern, PA,
manufactures a line of precision wirewound resistors, including
temperature-sensitive (i.e. high positive TCR) types.

Tel Labs is now a defunct outfit, of course; they were bought by
Ultronix some years ago.  While the Q81 itself is no longer
available, Ultronix still manufactures a product, called the model U81,
that is very similar to the Q81, however there are some differences as
follows:

The Q81 was a power-type wirewound resistor built on a ceramic core;
the U81 is built on a plastic core, and therefore has a much lower
power and temperature rating.  Specifically, the Q81 was rated 3 Watts
at 25?C, with a max. operating temperature of 275?C.  The U81 is rated
1/8 Watt up to 125?C, with a max. operating temperature of 145?C.

The lead diameter of the Q81 was 0.032" (#20AWG); the lead diameter of
the U81 is 0.026" (#22AWG).

Other than these slight differences, the Q81 and U81 are electrically
identical.  The TCR, ohmic value range, tolerance range, etc. of the
Q81 and U81 are the same.

(You referred to the Tel Labs "model Q81k" in your e-mail.  I don't
recognize what the "k" signifies; I've only ever heard of a plain old
Q81.)

Also, Ultronix can produce a +3500ppm/?C resistor in any of a variety
of package sizes and styles; these might be an option if the physical
size, power rating, lead diameter, etc. of the U81 are not acceptable.
For more info., visit the Ultronix web site at
http://www.vishayultronix.com/006/Product.html.

Yes, this part is available either through distribution, or direct from
the factory, in small quantities.  The part number for a 2kohm ? 1%
resistor would be:

U81 2K0000 1%

A list of distributors is on the web at
http://www.vishay.com/RepList/americas.html

Any further questions, please ask me by e-mail.

Regards,

Jim Vukich
Jim.Vukich at VISHAY.Com
-----------------------------------------

Steve Varner
varner at k-online.com






From zzynt at swipnet.se  Thu Jan  7 09:11:05 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 07 Jan 1999 00:11:05 -0800
Subject: DSP source!
Message-ID: <36946C19.5315@swipnet.se>

Need info about DSP?
Have a look at Roy Tates exelent source of DSP related things!! at:
http://www.hut.fi/Misc/Electronics/dsp.html
http://www.ionet.net/~roytate/#Other

BJ



From jorgen.bergfors at idg.se  Thu Jan  7 09:20:43 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 7 Jan 1999 9:20:43 +0100
Subject: VC Phaser using the LM13600
Message-ID: <TFSDWYIN@idg.se>

Hi Paul. The frequency shift at lower frequencies with 0V CV is probably due to the fact that I had to add a 2M2 resistor to ground, from the OTA output. Without it, the DC level will sometimes drift with no CV (the  OTA turned off). The load impedance in my circuit is very high because I used JFET opamp buffers instead of the LM13600 Darlington buffers. If I had used the buffers, I suppose the load resistance would have been lower than 2M2 ohms. The Small Stone used the Darlington buffers in the CA3094, so I suppose it is worse than my circuit in this respect. It is possible that I could improve it by using an even larger resistor, but 2M2 was the largest that I got.


/Jorgen





MIME:pfperry at melbpc.org.au on 99-01-05 13:39:41
To:  Jorgen Bergfors at IDGSE
cc:  Subject: Re: VC Phaser using the LM13600 

At 10:59 AM 5/01/99 +0100, you wrote:
>Hi all.

>The following was measured om my test circuit:

>As can be seen, there is some phase shift at lower frequencies even when
the control voltage is 0 volts. The frequency response falls to -3 dB at 24
Hz. This is the worst case, at 5V CV. At 10V CV it seems to be flat down to
DC. At 0V CV it goes down to 18 Hz. There is no HF damping (below 20 kHz).
>Noise and distortion seems to be low. I haven't measured them, but they
aren't noticable on the scope or at listening tests.
>Note that phase shift is higher att low frequencies. Is this common to all
phasers or are there phasers that are the other way round (higher phase
shifts at high frequencies)?

perhaps this is a function of the filter capacitors?
Try making them all one quarter the size..

paul perry melbourne australia










From varner at k-online.com  Thu Jan  7 09:30:34 1999
From: varner at k-online.com (Steve Varner)
Date: Thu, 07 Jan 1999 00:30:34 -0800
Subject: Kits n stuff
References: <99010604320608.08380@Pandemonium>
Message-ID: <369470A5.26631198@k-online.com>

Irish,

You are way ahead of a lot of people with your knowledge of electronics! I'm a
physicist, so I know some theory but lack all your experience. I think all you
need are some books. You should have no trouble building synth modules. One thing
you might do is to build a few simple modules and not worry about drift, tracking,
controllers, etc. There are some "utility" voltage controlled oscillator designs
and even some that use only transistors (no ICs!). You could build a VCO, a simple
filter, a voltage controlled amplifier, a simple triangle-square low frequency
oscillator, and a simple attack-decay envelope generator to define the note's
beginning and end. With your experience you could probably build these very
quickly.
One experience I *did* have was taking three semesters of electronic music at
university. One of our machines was a very big modular in a very tiny room (think
closet). Patching all those modules together in weird ways really taught me a lot.
You might look around for classes, it could happen that some university near you
has some synth studio in the basement.

SV

Irish wrote:

> Alright, I've read for a couple of days now, and to be truthful a bunch of this
> is over my head.
> Let me explain; I am (was) a GMP/MilSpec rated assembler. I can ID almost any
> part made, interpret schematics and drawings, and perform amazing feats of art
> in solder using a dizzying array of tools from $2.98 snips to $160,000 PnP
> machines.
> What I am not is an engineer. I know what various components are and do, and
> in a general way I know what happens when you put certain ones in a circuit
> together. I can use a meter but not a scope.
>
> Now, what I'd like to do is learn some theory, specifically as it relates
> to our mutual interest :) , but to start out it might help me to understand
> what all these things (like LFOs, VCFs, filters, modulators, etc. ) DO
> individually and when hooked together. To that end I would like to find some
> kits. I've already ordered the MadMouse - looks like fun to make and use. I'd
> also like to find some signal processing / effects type stuff. Ring Mod maybe,
> or analog delay? Stuff that's a kit, but winds up being cool useable gear. I've
> tried a few web searches, but come up empty. Any pointers folks?
>
> If I may, I'd also like to ask your patience if I come up with some
> ridiculously simple sounding questions. For example, I want to build a Midi
> Thru box. I have a very simple diagram (it's not rocket science...) that calls
> for a 74LS14. I can get it at RS or a local distrib for under a buck, BUT it's
> a 14 pin DIP and the diagram naturally just shows the symbols, not the pinout.
> Where can I find pinout for this and other common-as-dirt ICs? Again, web
> searches I made were fruitless. This really seems silly - these must be
> referenced somewhere on the net!
>
> Thanks for your help,
> Irish






From jorgen.bergfors at idg.se  Thu Jan  7 09:35:26 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 7 Jan 1999 9:35:26 +0100
Subject: VC Phaser using the LM13600
Message-ID: <TFSDXLKC@idg.se>

>Hello,
>The phase versus frequency function for a typical single RC all-pass
>filter is given by

> phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter and

>phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type filter.

Well, I suppose my question should have been: Which of the commercial phasers use lagging and which use leading filters? Can the Hammond scanning vibrato be considered leading or lagging?

I suppose my phaser (and the Small Stone) would be of the leading type, as the frequency shift gets lower at higher frequencies (if f=0 then phase is -180 degrees). But if you look at the oscilloscope, the signal moves left when the phase shift is increased. Because the oscilloscope trace moves from left to right, it must mean the signal is delayed and therefore lagging! Right?

/Jorgen 



From jorgen.bergfors at idg.se  Thu Jan  7 09:43:48 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 7 Jan 1999 9:43:48 +0100
Subject: Wiggins Circlotron
Message-ID: <TFSDXSVJ@idg.se>

Well, you always need dual power supplies to be able to DC-couple signals. That is the basis for all normal op-amp designs. What is so special about this? It sounds like some mumbo-jumbo designed to impress audiophiles that know nothing about electronics design.

/Jorgen





MIME:b.layer at vikingelectronics.com on 99-01-05 19:20:04
To:  synth-diy at mailhost.bpa.nl @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Wiggins Circlotron 

Hey All,

(This is a bit obscure, but...)

Has anyone on the list (besides me) ever experimented with Circlotron
output sections for pre or power amplifiers? This is a very unusual type of
circuit, and is currently highly controversial.

For those of you that don't know, the circlotron section is a novel method
of direct-coupling a signal output (sans caps or xfmrs, which have a way of
wrecking musical signals). An unusual feature of the design is that it
requires two identical floating power supplies to function.

Anyone?


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"









From irish at eskimo.com  Thu Jan  7 10:19:38 1999
From: irish at eskimo.com (Irish)
Date: Thu, 7 Jan 1999 01:19:38 -0800
Subject: Kits n stuff
References: <343c8448.3693e90c@aol.com>
Message-ID: <99010701311002.10364@Pandemonium>

Wow, thank you everyone! Got quite a lot of information on both subjects to
keep me busy, for a few days at least :) 

On Wed, 06 Jan 1999, DinedHavoC at aol.com typed:
>In a message dated 1/6/99 4:28:49 PM Central Standard Time, guidogoe at xs4all.nl
>writes:
><< In general, you should experiment with this, that is if you own an (analog)
>synth, you do, don't you???
> 
> Guido /THD Studio >>
>
>Im almost sure that Irish here doesnt own an analog synth, 

Well, I sort of do. I have a Korg Poly800, but as you probably know this not
the greatest instrument to learn on (not that there's anything wrong with it
for what it is...). 

> but if u decide to
>get one Irish, then id like to make some suggestions.
>The Sequential Circuits Pro One is an analog synth, 2 oscillators, one VCF
>(voltage controlled filter) with ADSR, one VCA (VOltage controller amplifier),
>a 40 step sequencer, an arpeggiator with two patterns, glide control, and an
>LFO.  I suggest it  as a great first analog as it is your basic "ordinary"
>analog synth.  

Woah! Sounds very cool indeed. I'd love to own one; what do they cost usually? 

>A few things u have to understand when making an analog synth purchase:
>1.  They are unstable.  You have to tune them often.
>2.  To much heat (above room temp) is BAD for an analog synth.
>3.  You have to buy most of them used, as most are out of production except a
>chosen few (Pulse, ATC1, etc.).
>4.  You dont get ANY MIDI unless you retrofit it which costs $$$$$ squared!!!
>Ofcourse you always have control voltage outputs, which i think r a lot cooler
>( ;
>5.  Because most analog synths stopped production around the early eighties,
>its quite a task to find one in perfect working order.  Much less mostly
>working order.
>6.  Most analogs are MONOPHONIC. This means one note at a time!

These are decidedly Good Things to Know - thank you. 

I have questions about CV, as I know nothing about it, but am pretty
comfortable with MIDI. I'll save them for another thread though...
 >
>Sorry for the bandwidth,
>~Dave~

No need to apologise, very helpful stuff! :) 
Thank you, 
Irish



From Colin.Fraser at scottishpower.plc.uk  Thu Jan  7 11:57:12 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Thu, 7 Jan 1999 10:57:12 -0000 
Subject: Dodgy 3340s
Message-ID: <BA865FF10473D211BC6F00805F0D830702D28E@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Tony Allgood [mailto:oakley at techrepairs.freeserve.co.uk]
> Sent: 07 January 1999 21:17
> To: synth diy
> Subject: Re: AW: VCO-1C #2
> 
> 
> Ingo wrote:
> I'm asking because in my selfmade poly synth (without 
> autotune) nine of
> the ten 3340s are pretty stable, after a warm up time of 20 minutes or
> so. But one is drifting very much. I thought that one had 
> gone bad, but
> maybe I just had luck with the other nine?
> 
> Tony writes:
> Me too. I have two bad ones out of 16 VCOs. I replaced the really bad
> one with another and I think its liveable with. I have just 
> been mailed
> by someone, Colin F I think, who said that Roland selected their CEMs
> for the Jp8. I don't know whether thats true, but some 3340s 
> are better
> than others. They will always be fine for a mono, it is as you say, a
> real bummer in a poly. 

Kevin L has a copy of the Roland service bulletin about this at
http://www.synthfool.com/cem3340.gif 
Roland selected the 3340s for the JP6, MKS80 and SH101.

Seems like that later production runs weren't so good...
Someone recently said somewhere that Roland may still have stock of spare
3340s, which would already be selected, so that may be a good source.
Personally, I'm not planning on using 3340s again (except for replacement if
a Pro-One vco dies). It's cheaper and not much more difficult to build a
stable discrete oscillator.

Colin f






From fa_diy at fa.camelot.de  Thu Jan  7 12:12:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 07 Jan 1999 13:12:00 +0200
Subject: AW: Filters?
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D582011517E5@nbgm336a.nbgm.siemens.de>
Message-ID: <78OoPhg4HFB@fa.camelot.de>

Hallo Juergen

>>type (Rogue, TR303) were bigger than the difference between the
>>different brands!
>[...]do care more about the way they are arranged, than for the
>nameplate on the enclosure ? (Sorry, couldn't resist.)
;-)) got me.

What I meant: we had a 303-Filter that sounded very close to a Rogue, while  
the two Rogues differed a lot and also the Rogue, which was close to the 303,  
differed a lot from the MiniMoog.

Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 12:24:58 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 12:24:58 +0100 
Subject: AW: VC Phaser using the LM13600
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151CD2@nbgm336a.nbgm.siemens.de>

	>> phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter
and
	>
	>>phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type
filter.
	>
	>Well, I suppose my question should have been: Which of the
commercial >phasers use lagging and which use leading filters? Can the
Hammond scanning >vibrato be considered leading or lagging?
	>
	>I suppose my phaser (and the Small Stone) would be of the leading
type, as the >frequency shift gets lower at higher frequencies (if f=0 then
phase is -180 >degrees). But if you look at the oscilloscope, the signal
moves left when the >phase shift is increased. Because the oscilloscope
trace moves from left to right, >it must mean the signal is delayed and
therefore lagging! Right?

I have a stupid question: Does this leading / lagging distinction
make any sense at all ? I mean, you only can *delay* a signal
anyway, and the phase shift is just the delay normalized to an
angle for a certain frequency. I'd say the 180 degree difference
in the above equation is just a signal inversion. (I know there
are cases where it's useful to speak of lead and lag, but I doubt
it is when you build delay units like phasers.)

JH.




From fa_diy at fa.camelot.de  Thu Jan  7 12:31:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 07 Jan 1999 13:31:00 +0200
Subject: Sampling and Nyquist/Antialiasing filters
In-Reply-To: <36924E13.31DF@ptdcs2.intel.com>
Message-ID: <78OoQ224HFB@fa.camelot.de>

Hello Duane


>Is there anyone out there who has any basic guidelines on how many dB
>down "aliasing" frequencies have to be so they are not a problem?
I had the same problem with my Casio FZ-1. (36 kHz sampling rate and 14 kHz  
filter). After two heretical thoughts, I decided only to modify the input  
filter that way, that I can switch it off(!):

1.) the most sounds that I am sampling come from media that don't have the  
critical frequency-range (even on the best recorded CD there is no frequency  
over 22 kHz) so I don't have to care for.

2.) A sampler like a Prophet 2000 or the FZ-1 is a sampler and the sampler  
should sound like a sampler - not as perfect as the real world. If there is a  
little aliasing noise it doesn't disturb me, it is more like some glittering  
exciter effect.

Now I have a simple switch, witch bypasses the input-filter (and also one,  
that disables the signal routing for filtering at lower sampling rates, which  
is done in the FZ-1 with the Playback-DCFs). I insert a 24 dB Curtis filter  
(modified Doepfer A-122) in the input signalpath so that I can adjust the  
cutoff frequency to my desire. Easy thing, works very well ...


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 12:36:23 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 12:36:23 +0100 
Subject: AW: AW: VCO-1C #2
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151CE9@nbgm336a.nbgm.siemens.de>

	>Ingo wrote:
	>I'm asking because in my selfmade poly synth (without autotune)
nine of
	>the ten 3340s are pretty stable, after a warm up time of 20 minutes
or
	>so. But one is drifting very much. I thought that one had gone bad,
but
	>maybe I just had luck with the other nine?
	>
	>Tony writes:
	>Me too. I have two bad ones out of 16 VCOs. 

Same for me. Some are fine, some not.

	>I have just been mailed
	>by someone, Colin F I think, who said that Roland selected their
CEMs
	>for the Jp8. I don't know whether thats true, but some 3340s are
better
	>than others. They will always be fine for a mono, it is as you say,
a
	>real bummer in a poly.

The JP8 has discrete VCOs - no 3340's here. It might have been
the MKS-80. What I heard (but that's only from hearsay, too) is
that Roland selected just the other way round: The good ones
for the Monosynth (without autotune), and the not so good ones
for the Polysynth (where you need an autotune anyway).

JH.




From jorgen.bergfors at idg.se  Thu Jan  7 12:37:46 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 7 Jan 1999 12:37:46 +0100
Subject: AW: VC Phaser using the LM13600
Message-ID: <TFSEDRFU@idg.se>

>>> phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter
and
 >>
 >>>phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type
filter.
 >
 >>Well, I suppose my question should have been: Which of the
commercial >phasers use lagging and which use leading filters? Can the
Hammond scanning >vibrato be considered leading or lagging?
 >>
 >>I suppose my phaser (and the Small Stone) would be of the leading
type, as the >frequency shift gets lower at higher frequencies (if f=0 then
phase is -180 >degrees). But if you look at the oscilloscope, the signal
moves left when the >phase shift is increased. Because the oscilloscope
trace moves from left to right, >it must mean the signal is delayed and
therefore lagging! Right?

>I have a stupid question: Does this leading / lagging distinction
make any sense at all ? I mean, you only can *delay* a signal
anyway, and the phase shift is just the delay normalized to an
angle for a certain frequency. I'd say the 180 degree difference
in the above equation is just a signal inversion. (I know there
are cases where it's useful to speak of lead and lag, but I doubt
it is when you build delay units like phasers.)

>JH.

I suppose the difference is that the leading type delays mainly low frequecies, whereas the lagging type delays high frequencies the most. Or have I got it wrong? But if that is the case, how does it affect the sound? I.e. how different do the leading and lagging types sound?

/Jorgen





From fa_diy at fa.camelot.de  Thu Jan  7 12:41:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 07 Jan 1999 13:41:00 +0200
Subject: Digital DIY synths?
In-Reply-To: <99010600424400.08380@Pandemonium>
Message-ID: <78OoQbVpHFB@fa.camelot.de>

Hello Ben,

>Switches? You had switches? Man, we had to bang two rocks together to get any
>sound and use lightning for special effects. And we were grateful for it.
Did you read Magnus answer? We should bang not two rocks, we should bang two  
symphonic orchestras...

>I feel a Monty Python thread coming up...
The first violinist will say: "ooh, it's only a scratch..."


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 13:08:45 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 13:08:45 +0100 
Subject: gifs on diy
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>

Hi all,

I have seen several pictures posted to the entire list recently.
This used to be unwanted in the past, because it costs bandwidth
for *everyone* who is subscribed, not only the ones particularly 
interested in the pictures.

OTAH, I would rather have sent one or the other little image 
myself, rather than making long verbal descriptions, but I
didn't so far, because of the "rules".

Now speed and bandwidth surely have improoved meanwhile,
so it would make sense to loosen the rules a little. 
So I don't want this to be a "don't post pictures" post. But we
should find a general rule about pictures, IMO. At least a size
limit. 

What do you think ?

JH.



From fa_diy at fa.camelot.de  Thu Jan  7 13:30:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 07 Jan 1999 14:30:00 +0200
Subject: Dodgy 3340s
In-Reply-To: <BA865FF10473D211BC6F00805F0D830702D28E@catsprntp01.cat.scottishpower.plc.uk>
Message-ID: <78OoU8bKHFB@fa.camelot.de>

Hallo Colin

>Someone recently said somewhere that Roland may still have stock of spare
>3340s, which would already be selected, so that may be a good source.
That is true. But they let ble... eeehm, ... pay you (70 Deutschmarks!)



Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From fa_diy at fa.camelot.de  Thu Jan  7 13:46:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 07 Jan 1999 14:46:00 +0200
Subject: AW: VC Phaser using the LM13600
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58201151CD2@nbgm336a.nbgm.siemens.de>
Message-ID: <78OoUKMKHFB@fa.camelot.de>

Hello Juergen

>it is when you build delay units like phasers.)
I am not the hero of electronic theory, but as far as I understand the  
explanation of allpass-filters. I have read but not completely understood  
Tietze/Schenk, Halbleiterschaltungstechnik, Berlin, 1980, pg. 317ff.

To my knowledge you are theoretically right, but practically a "phaser" is  
not a perfect delay. It is an allpass filter, which makes a delay, but only  
below the centerfrequency. Around and over the centerfrequency, the delay  
gets shorter. Therefor Tietze/Schenk do not call it delay but "frequency  
depending phase shift".

The (audible) difference between phaser an flanger is the difference of the  
combfiltershapes which result from the difference between the perfect digital  
delay that is used for the flanger and the "nonlinear" (don't know how to  
explain) delay of the phaser.


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From james at newd.demon.co.uk  Thu Jan  7 13:50:58 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Thu, 07 Jan 1999 12:50:58 +0000
Subject: gifs on diy
Message-ID: <1.5.4.32.19990107125058.006734d0@pop3.demon.co.uk>

>Now speed and bandwidth surely have improoved meanwhile,
>so it would make sense to loosen the rules a little. 
>So I don't want this to be a "don't post pictures" post. But we
>should find a general rule about pictures, IMO. At least a size
>limit. 

How about a 5-10KB size limit?

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 14:12:39 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 14:12:39 +0100 
Subject: AW: AW: VC Phaser using the LM13600
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201151DEB@nbgm336a.nbgm.siemens.de>

	>I suppose the difference is that the leading type delays mainly low
frequecies, >whereas the lagging type delays high frequencies the most. 

I don't think so. The group delay for both cases is exactly the
same. It's fairly constant for low freq, and then goes down for 
higher freq. The 180 degrees "phase difference" between the
two circuits is actually a signal inversion, *not* an additional
delay. (Always look at the delay, not the phase, in the first place.
Phase is quite ambiguous.)

	>Or have I got it wrong? But if that is the case, how does it affect
the sound? I.e. how >different do the leading and lagging types sound?

Different implementations will differ because of different parasitics,
different nonlinearities etc.

JH.




From Colin.Fraser at scottishpower.plc.uk  Thu Jan  7 14:17:38 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Thu, 7 Jan 1999 13:17:38 -0000 
Subject: gifs on diy
Message-ID: <BA865FF10473D211BC6F00805F0D830702D293@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 07 January 1999 12:09
> To: DIY
> Subject: gifs on diy
> 
> I have seen several pictures posted to the entire list recently.
> This used to be unwanted in the past, because it costs bandwidth
> for *everyone* who is subscribed, not only the ones particularly 
> interested in the pictures.
> 
> OTAH, I would rather have sent one or the other little image 
> myself, rather than making long verbal descriptions, but I
> didn't so far, because of the "rules".
> 
> Now speed and bandwidth surely have improoved meanwhile,
> so it would make sense to loosen the rules a little. 
> So I don't want this to be a "don't post pictures" post. But we
> should find a general rule about pictures, IMO. At least a size
> limit. 

I only use e-mail at work, where we have plenty bandwidth, so I don't mind
small files at all. *But* if it is seen as normal to send files to the list,
someone who doesn't understand how big a file is may piss a lot of people
off by sending a huge file to a list - I know a guy who sent a 1.6Meg bitmap
to another list, and he wasn't very popular.

I would say if a file is less than 100k it would be OK for most people - but
what if someone mistakes M for k ?

Colin f



From wils0450 at itlabs.umn.edu  Thu Jan  7 15:19:50 1999
From: wils0450 at itlabs.umn.edu (Claire F.)
Date: Thu, 7 Jan 1999 08:19:50 -0600 (CST)
Subject: gifs on diy
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>
Message-ID: <Pine.GSO.4.05.9901070818120.10745-100000@whale.itlabs.umn.edu>

On Thu, 7 Jan 1999, Haible Juergen wrote:
> Now speed and bandwidth surely have improoved meanwhile,
> so it would make sense to loosen the rules a little. 
> So I don't want this to be a "don't post pictures" post. But we
> should find a general rule about pictures, IMO. At least a size
> limit. 

Not a bad idea. In fact, if you don't mind H.J., I'd like to steal it as
an idea for a "Bulletin Board" type user post area (redundancy) on my web
page! :)

                 "There always lies so near to us a realm
        in which we have escaped entirely from all our affliction..."






From beszedes at cc.u-szeged.hu  Thu Jan  7 15:40:11 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Thu, 07 Jan 1999 15:40:11 +0100
Subject: gifs on diy
References: <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>
Message-ID: <3694C74B.C34673D8@cc.u-szeged.hu>

Hi!

Haible Juergen wrote:

> for *everyone* who is subscribed, not only the ones particularly
> interested in the pictures.
> 

Well, this is not completely the truth, because one can disable in the
mailing program downloading messages greater than some limit. Eg. in
Netscape Messanger: Preferences/Disk space. 

> should find a general rule about pictures, IMO. At least a size
> limit.
> 

Say, 50kbytes would be okay?

Regards,
  Arpad.

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************



From wils0450 at itlabs.umn.edu  Thu Jan  7 15:52:28 1999
From: wils0450 at itlabs.umn.edu (Claire F.)
Date: Thu, 7 Jan 1999 08:52:28 -0600 (CST)
Subject: Beginner's question
Message-ID: <Pine.GSO.4.05.9901070844150.10770-100000@whale.itlabs.umn.edu>

Ok, I am trying to build a real "etheral" and "Pad-friendly" synth. I want
to do it up kind of *like* the OB Matrix-100, but with frontpanel controls
and twisty knobs. The only problem is, I don't know what (if it even
matters) *kinds* of oscillators to use to produce an "etheral" effect.
Can one kind of oscillator be that much better for one kind of sound than
another? If so, would this same aspect apply to VCA, VCF etc. ? 
Thanks in advance!


			 The Family Werks presents...
                          Performing live at "Love"
		Valentine's day weekend in Minneapolis, MN USA
             ****Sonic Boom of Love featuring Clarissa Fragile*****
	       (also Boo WIlliams and some other big-name chumps)





From brun at bart.nl  Thu Jan  7 16:17:02 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Thu, 7 Jan 1999 16:17:02 +0100
Subject: gifs on diy
In-Reply-To: <BA865FF10473D211BC6F00805F0D830702D293@catsprntp01.cat.scottishpower.plc.uk>
Message-ID: <199901071518.QAA12027@smtp3.xs4all.nl>

I agree. For smaller pics, it's ok. And for those that are bigger than 
100k, one could upload it to a website and only post the URL here. 
It would save a lot of unnecessary downloadseconds.

> > Now speed and bandwidth surely have improoved meanwhile,
> > so it would make sense to loosen the rules a little. 
> > So I don't want this to be a "don't post pictures" post. But we
> > should find a general rule about pictures, IMO. At least a size
> > limit. 
> 
> I only use e-mail at work, where we have plenty bandwidth, so I don't mind
> small files at all. *But* if it is seen as normal to send files to the list,
> someone who doesn't understand how big a file is may piss a lot of people
> off by sending a huge file to a list - I know a guy who sent a 1.6Meg bitmap
> to another list, and he wasn't very popular.
> 
> I would say if a file is less than 100k it would be OK for most people - but
> what if someone mistakes M for k ?




-> Brun, met een dakje op de u.

Nu aan het knutselen op http://www.bart.nl/~brun/index.htm



From b.layer at vikingelectronics.com  Thu Jan  7 16:18:00 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 07 Jan 1999 09:18:00 -0600
Subject: Wiggins Circlotron
In-Reply-To: <TFSDXSVJ@idg.se>
Message-ID: <3.0.6.32.19990107091800.007ba310@192.168.210.18>

Hi Jorgen,

>Well, you always need dual power supplies to be able to DC-couple signals.
That is the basis for all normal op-amp designs. What is so special about
this? It sounds like some mumbo-jumbo designed to impress audiophiles that
know nothing about electronics design.

OK.

The Circlotron stage was invented in the mid 1950's, and today forms the
basis of design for Balanced Audio Technology, Sumo, Atma-Sphere and
others. It is a fully symmetrical balanced design, which requires only
*two* active devices, and is not an operational amplifier. It was first
conceived as a cost-saving approach to the problem of large, expensive
transformers required for increasingly powerful tube amplifiers.

Since the output has no DC, the transformer may be much smaller as bias
current saturation is a non-issue. It was later realized that the
transformer was not actually required, if the output impedance of the power
tubes could be made low enough to transfer usable power to a load. 

The point of this, is that the design works even better for solid state
devices, as they have naturally low output impedances. By substituting a
Circlotron section for an op-amp, the cost of the op-amp is saved and the
signal maintains better integrity as it passes through only a single
differential pair (which also has a very high degree of common-mode
cancellation), rather than the group of active devices in the op-amp.

A second consideration is the tremendous potential bandwidth, or speed of
the design.

Also, I tend to think of op-amp power supplies as bi-polar, rather than
dual. The supplies of the circlotron are not necessarily referenced to one
another, and may be thought of as two  simple batteries. In practice, the
_negative_ side of _both_ supplies are often referenced to ground, for the
practical purpose of controlling bias in the output devices. 

I'll make available a .gif of a circlotron section later today.

In the meantime, those interested should check out
<hrrp://www.condor-connection.org/asog>. There may be one posted already.


___      ___
\  \    /  /    E L E C T R O N I C S                Bill Layer
 \  \  /  / _   _  _   _   __  _   _____          Sales Technician
  \  \/  / | | | |/ / | | |  \| | /  _  \  <b.layer at vikingelectronics.com>
   \    /  | | |   \  | | |     | | (_) | 
    \__/   |_| |_|\_\ |_| |_|\__| \___  |     1531 Industrial Street
                                    __/ /     Hudson, WI. 54016 U.S.A
 http://www.vikingelectronics.com> /___/      715.386.8861 ext. 210




From Colin.Fraser at scottishpower.plc.uk  Thu Jan  7 16:27:33 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Thu, 7 Jan 1999 15:27:33 -0000 
Subject: Dodgy 3340s
Message-ID: <BA865FF10473D211BC6F00805F0D830702D294@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: fa_diy at fa.camelot.de [mailto:fa_diy at fa.camelot.de]
> Sent: 07 January 1999 12:30
> To: synth-diy at mailhost.bpa.nl
> Subject: Re: Dodgy 3340s
> 
> >Someone recently said somewhere that Roland may still have 
> stock of spare
> >3340s, which would already be selected, so that may be a good source.
> That is true. But they let ble... eeehm, ... pay you (70 
> Deutschmarks!)

Unfotunately, 70DM (= 25UKP = 40USD) is not such a bad price for a 3340
these days...
I paid about 15UKP each for them when I bought some direct from the
manufacturers (OnChip), and that was a couple of years ago.

It's one of those supply/demand things.

Colin f



From martink at cix.co.uk  Thu Jan  7 16:56:00 1999
From: martink at cix.co.uk (Martin J Keefe)
Date: Thu, 7 Jan 1999 15:56 +0000 (GMT)
Subject: DSP Stuff
In-Reply-To: <3693BA2B.9DE5D5E9@globaleyes.net>
Message-ID: <memo.19990107155654.262C@martink.compulink.co.uk>


> Nope.. this is also the misconception I had.. its not actually a SHARC..
> The devkit for the SHARC is about  1k dollars... Although, the ezkit

There is a SHARC EZ-KIT (has an ADSP-21061 on it). I got mine from Maplin 
in the UK for about ?160. Haven't had much time to play with it yet. The 
chip itself is definitely NOT a DIY item -- 100s of the tiniest surface 
mount legs I've seen, spaced very close together.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From don at till.com  Thu Jan  7 17:53:27 1999
From: don at till.com (Don Tillman)
Date: Thu, 7 Jan 1999 08:53:27 -0800 (PST)
Subject: VC Phaser using the LM13600
Message-ID: <199901071653.IAA01561@shell9.ba.best.com>

   From: jorgen.bergfors at idg.se
   Date: Thu, 7 Jan 1999 9:35:26 +0100

   Well, I suppose my question should have been: Which of the
   commercial phasers use lagging and which use leading filters? Can
   the Hammond scanning vibrato be considered leading or lagging? 

The Hammond scanner lags, but it's a delay line, not a phase shifter.  

   From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
   Date: Thu, 7 Jan 1999 12:24:58 +0100 

   I have a stupid question: Does this leading / lagging distinction
   make any sense at all ? 

No difference at all.  It's just signal inversion (and individual
circuit peculiarities, of course).

   Date: 07 Jan 1999 14:46:00 +0200
   From: fa_diy at fa.camelot.de (Florian Anwander)

   To my knowledge you are theoretically right, but practically a
   "phaser" is not a perfect delay. It is an allpass filter, which
   makes a delay, but only below the centerfrequency. 

Phase shift and delay are very different and should not be confused.

A phase shifter circuit really has no delay, above or below the center
frequency.  It just shifts the phase.  This is important: any change
at the input of a phase shifter will always show up in the output
immediately.

The amount of phase shift in a phase shift circuit below the center
frequency is roughly equivalent to the measured phase shift of a delay
line, but that's a case of two different processes measuring
similiarly on some arbitrary gauge.

  -- Don




From magnus at analogue.org  Thu Jan  7 18:02:49 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 07 Jan 1999 18:02:49 +0100
Subject: AW: VC Phaser using the LM13600
In-Reply-To: Your message of "Thu, 7 Jan 1999 12:24:58 +0100 "
References: <1BF5E20E0C4DD111BBAB00805FE2D58201151CD2@nbgm336a.nbgm.siemens.de>
Message-ID: <199901071702.SAA17860@mail2.it.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 >>> phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter
 HJ> and
 >> 
 >>> phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type
 HJ> filter.
 >> 
 >> Well, I suppose my question should have been: Which of the
 HJ> commercial >phasers use lagging and which use leading filters? Can the
 HJ> Hammond scanning >vibrato be considered leading or lagging?
 >> 
 >> I suppose my phaser (and the Small Stone) would be of the leading
 HJ> type, as the >frequency shift gets lower at higher frequencies (if f=0 then
 HJ> phase is -180 >degrees). But if you look at the oscilloscope, the signal
 HJ> moves left when the >phase shift is increased. Because the oscilloscope
 HJ> trace moves from left to right, >it must mean the signal is delayed and
 HJ> therefore lagging! Right?

 HJ> I have a stupid question: Does this leading / lagging distinction
 HJ> make any sense at all ? I mean, you only can *delay* a signal
 HJ> anyway, and the phase shift is just the delay normalized to an
 HJ> angle for a certain frequency. I'd say the 180 degree difference
 HJ> in the above equation is just a signal inversion. (I know there
 HJ> are cases where it's useful to speak of lead and lag, but I doubt
 HJ> it is when you build delay units like phasers.)

Well, for the all-pass filter, you got n poles at -v on the real axis
and n zeros at +v on the real axis. Thus

                n
         (s - v)
H  (s) = --------
 AP             n
         (s + v)

where n is typically 4 or 6. The phase responce becomes

                     -w              -w              w
phi(jw) = n * arctan -- - n * arctan -- = 2*n*arctan -
                     -v               v              v

For this type of all-pass filters there is not really much more to
add, this is the way they behave.

Now, an all-pass filter is not all there is to a phaser, you need to
sum the output of the all-pass with the input. This has the responce
of
                                                     n            n
                                        n   c (s + v)  + c (s - v)
                                 (s - v)     1            2
H  (s) = c  + c H  (s) = c  + c  -------- = ---------------------
 PH       1    2 AP       1    2        n                 n
                                 (s + v)           (s + v)

So, dependent on how set mix c1:c2 is set, the zeros are moved from -v
(the pole positions, no effect) to +v (the all-pass zero
position). This will ofcourse change the phase behaviour between these
two cases.

Then, you could also throw in some feedback term, just for the fun of
it, this will spread the poles and the phase responce will not be as
simple.

As for lead/lag - you can't break the casuallilty without getting into
trouble with Einstein. There have been some trouble regarding how low
intensity (photon per photon) interferometers actually work with this
respect and the best explanation comes from the transaction
description of this interaction. Also, further trouble have been in
the discussions of how fast a jump over a barriers (such as in a
tunnel diod) actually takes, there are people discussing speeds in
superluminar levels (that is, _faster_ than light). In Germany they
had some fun and sent Mozart at 4.5 times the speed of light, without
any noticable distorsion over a distance of 11 cm. Hope this is
confusing ;)

Cheers,
Magnus



From magnus at analogue.org  Thu Jan  7 18:06:59 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 07 Jan 1999 18:06:59 +0100
Subject: Digital DIY synths?
In-Reply-To: Your message of "07 Jan 1999 13:41:00 +0200"
References: <78OoQbVpHFB@fa.camelot.de>
Message-ID: <199901071706.SAA17936@mail2.it.kth.se>

>>>>> "FA" == Florian Anwander <fa_diy at fa.camelot.de> writes:

 FA> Hello Ben,
 >> Switches? You had switches? Man, we had to bang two rocks together to get any
 >> sound and use lightning for special effects. And we were grateful for it.

 FA> Did you read Magnus answer? We should bang not two rocks, we should bang two  
 FA> symphonic orchestras...

Right, is this what they call "Orchestra hit"?

Used to be such a common sample, but maybe there is no more orhestras
to hit...

 >> I feel a Monty Python thread coming up...

 FA> The first violinist will say: "ooh, it's only a scratch..."

... and here is the machine that goes BING!

Cheers,
Magnus



From costello at seanet.com  Thu Jan  7 18:25:20 1999
From: costello at seanet.com (Sean Costello)
Date: Thu, 07 Jan 1999 09:25:20 -0800
Subject: AW: AW: VCO-1C #2
References: <1BF5E20E0C4DD111BBAB00805FE2D58201151CE9@nbgm336a.nbgm.siemens.de>
Message-ID: <3694EE00.75E9EFA1@seanet.com>

Haible Juergen wrote:

> The JP8 has discrete VCOs - no 3340's here. It might have been
> the MKS-80. What I heard (but that's only from hearsay, too) is
> that Roland selected just the other way round: The good ones
> for the Monosynth (without autotune), and the not so good ones
> for the Polysynth (where you need an autotune anyway).

I thought that the CEM VCO's for the JP-6 and MKS-80 were selected for
how well they would behave using Roland's hard sync.  Chips that would
not sync properly would still be perfectly suited for the SH-101 and
MC-202, where no syncing ability was necessary.

I don't know where I heard it, and I have no idea why I would remember
such a factoid.

Sean Costello



From Chris.List at sc.siemens.com  Thu Jan  7 18:26:01 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 7 Jan 1999 12:26:01 -0500
Subject: DSP Stuff
Message-ID: <81A062BC5305D111A9D700805F06596801836C48@maildepo.sc.siemens.com>

This is available from Newark Electronics for $178.55
- seems pretty darn cheap to me!

go here;
http://search.newark.com/product_search.phtml

and enter "Mfg. Part No. Starts With:     ADDS"

...and you'll find all the SHARC development kits available.
  
A short description of the ADDS-21061-EZLITE can be found here;
http://www.newark.com/C115_modules/19238.html

and the full specs are available in PDF format from Analog Devices here;
http://products.analog.com/products/pdf.asp?product=210XX-EZLITE

...Seems like a good deal, comes with a C compiler and whatnot. Anyone
care to comment?

- CList


> -----Original Message-----
> From:	martink at cix.co.uk [SMTP:martink at cix.co.uk]
> Sent:	Thursday, January 07, 1999 10:56 AM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Re: DSP Stuff
> 
> 
> > Nope.. this is also the misconception I had.. its not actually a
> SHARC..
> > The devkit for the SHARC is about  1k dollars... Although, the ezkit
> 
> There is a SHARC EZ-KIT (has an ADSP-21061 on it). I got mine from
> Maplin 
> in the UK for about ?160. Haven't had much time to play with it yet.
> The 
> chip itself is definitely NOT a DIY item -- 100s of the tiniest
> surface 
> mount legs I've seen, spaced very close together.
> 
>   ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 18:26:58 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 18:26:58 +0100 
Subject: AW: AW: VC Phaser using the LM13600
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820117E944@nbgm336a.nbgm.siemens.de>

	>To my knowledge you are theoretically right, but practically a
"phaser" is  
	>not a perfect delay. 

The delay is a function of frequency. It's not constant.
(but it's "fairly constant at low frequencies.")
My point was that it's always a *positive* delay, regardless of
the implementation of the all pass filter stage.

	>It is an allpass filter, which makes a delay, but only  
	>below the centerfrequency. Around and over the centerfrequency, the
delay  
	>gets shorter. Therefor Tietze/Schenk do not call it delay but
"frequency  
	>depending phase shift".

Sure. Which doesn't mean that you can't look at it as a "frequency
dependent delay" as well. One is the d/df of the other. Phase is
ambiguous in respect of N*360 degrees, and a 180 degrees
difference looks the same as a (zero delay) signal inversion.
Looking at the Delay rather than just the Phase may help avoiding
some confusion (in the original question). When we're going
on to look for the peaks and notches of the whole phaser, the use of Phase
rather than Delay is much more comfortable, of course.

	>The (audible) difference between phaser an flanger is the
difference of the  
	>combfiltershapes which result from the difference between the
perfect digital  
	>delay that is used for the flanger and the "nonlinear" (don't know
how to  
	>explain) delay of the phaser.

A delay that's constant over frequency (as in a Flanger) will result in
an extremely high amount of phase shift for high frequencies.
(The same very basic mathematical relationship
of phase shift, delay and frequency again.) So for high freq
you're crossing N*360 degree lines all the time. Thus the 
"comb" filter effect when you add the non-delayed signal.

As for implementation, a Flanger is no way restricted to digital
implementation. Reportetly it was invented with two tape reels
running in parallel (therefore the name), and there are many 
BBD-based flangers out there.

And as for "perfect digital delay", I always have problems with 
the words "perfect" and "digital" in one sentence (;->).

JH.




From B.vdWal at cetis.hvu.nl  Thu Jan  7 18:44:24 1999
From: B.vdWal at cetis.hvu.nl (Bauke van der Wal)
Date: Thu, 7 Jan 1999 17:44:24 +0000
Subject: gifs on diy
In-Reply-To: <BA865FF10473D211BC6F00805F0D830702D293@catsprntp01.cat.scottishpower.plc.uk>
Message-ID: <199901071644.RAA29759@Prlwytskofski.cetis.hvu.nl>

> > Now speed and bandwidth surely have improoved meanwhile,
> > so it would make sense to loosen the rules a little. 
> > So I don't want this to be a "don't post pictures" post. But we
> > should find a general rule about pictures, IMO. At least a size
> > limit. 
> 
> I would say if a file is less than 100k it would be OK for most people - but
> what if someone mistakes M for k ?

a short message from someone who is mainly on the list to read and 
learn (allthough very soon i will ask for your help because my fatman 
still doesn't work and i don't know where to look anymore - but due 
to a time-shortage ... well .. y'all get the point ...)

i think pictures in some cases are very clearifying, but i think it 
is better to find a small place somewhere on a server and keep it 
posted there for say 1 or two weeks (or even longer) because:

a) _if_ someone is interested he or she can download it anytime.

b) if a pic leads to a discussion, you are able to download it in the 
next couple of days - even in the midst of the discussion and it 
doesn't have to be resent to the list - which might lead to 
irritation to those not interested.

c) if the finger hits the delete button to fast ... well ... pointing 
your browser to a earlier made bookmark is easier than sending a mail 
to the list with the subject "urgent: needing pic from they day 
before yesterday, sent around 12 pm CET"

jmho ...

greetings
bauke

Bauke van der Wal - Cetis
Ontwikkelaar Nieuwe Media
Tel: 030 - 2586285



From bmcdonald at chyron.com  Thu Jan  7 19:05:47 1999
From: bmcdonald at chyron.com (Brian McDonald)
Date: Thu, 07 Jan 1999 10:05:47 -0800
Subject: Odyssey VCO problem
Message-ID: <3694F77B.E61044DE@chyron.com>

Well, I'm still trying to fix my Odyssey (model 2800) VCO problem
(problem being that VCO 2 will not scale and its frequency range is much
different from 20Hz-20kHz - seems like it goes to like 40kHz, although I
didn't measure this).  I brought it to a local tech (Thang Ho at
Musicians Service Center in San Jose), who couldn't determine the exact
problem, but suggested that it may be the CD4011 chip (a quad NAND gate)
or the 2N5459 FET.  

Does this sound like a possibility?  Any other possibilities?  I found
replacement parts for these at Mouser, and figure if all the tech was
going to do was trying swapping parts and rescaling the VCO, that I
could just as easily do that.  These parts are pretty cheap.

I have already verified that it is not the Tempco resistor, which was a
good suggestion from an AHer.  I had a similar problem when I built the
ASM-1 (I left out the Tempco and the VCO scaling was way, way out of
range - like a few octaves in the range of three notes!).

thanks for any help!

brian

-- brian mcdonald ---- -- --- -- - --- -- --- --- - software engineer --
-- bmcdonald at chyron.com -- --- Liberty! -- --- - -- chyron west coast --
-- (408) 873-3818 -- --- ---- -- - --- -- - ---- -- cupertino, ca     --



From costello at seanet.com  Thu Jan  7 19:09:55 1999
From: costello at seanet.com (Sean Costello)
Date: Thu, 07 Jan 1999 10:09:55 -0800
Subject: Beginner's question
References: <Pine.GSO.4.05.9901070844150.10770-100000@whale.itlabs.umn.edu>
Message-ID: <3694F873.CBF9269D@seanet.com>

Claire F. wrote:
> 
> Ok, I am trying to build a real "etheral" and "Pad-friendly" synth. I want
> to do it up kind of *like* the OB Matrix-100, but with frontpanel controls
> and twisty knobs. The only problem is, I don't know what (if it even
> matters) *kinds* of oscillators to use to produce an "etheral" effect.
> Can one kind of oscillator be that much better for one kind of sound than
> another? If so, would this same aspect apply to VCA, VCF etc. ?
> Thanks in advance!

A couple of options:

1) Do it up kind of *like* a Matrix 1000, and get the CEM 3396 chips
from Synthtech. Same chips used in the Matrix 1000.  Each chip has
waveshapers for two seperate oscillator pulse trains, as well as a
lowpass filter and an output VCA.  You will need a source for the pulse
trains - either VCOs, or DCOs.  The waveshaping probably contributes to
that sound you are looking for.

2) Do it up exactly *like* a Matrix 1000, and get a Matrix 1000. Then,
design a front panel for the Matrix 1000 with plenty of knobs, that
works by sending MIDI CC messages.  There is already at least one
commercial implementation of this, but it doesn't have knobs for every
controller.  Either you can design your own knob panel engine from
scratch, or you can purchase a kit from PAiA that takes 8 control
voltages and outputs 8 MIDI CC messages of your choice.  8 knobs might
not seem like enough, but how many knobs do you REALLY need to
manipulate a sound during performance?  Personally, I tend to mess with
filter cutoff, filter resonance, filter FM (if it is availabe on a
synth), oscillator detuning, envelope amount going to filter, pulse
width, and modulation amounts.  You could add a control on the Matrix
1000 panel, and control waveshaping live.  Everything else could be
programmed via the front panel or with an editing program; less
convenient for programming, but maybe not that inconvenient for live
performance.  8 knobs would fit nicely above the keyboard controller of
your choice (I have a nice cheap portable Roland PC-200 Mk II, which is
fairly nice, although I prefer wheels to the Roland bender stick). 
Hmmm...maybe I should look into getting this setup myself...

Beyond that, you need to answer a big question for yourself: What do you
consider "ethereal"?  Is it a quality of spectral motion?  Is it
regular, random, or somewhere in between?  I know that my Polysix does a
better job of producing sounds I would call "ethereal" than the Prophet
5 I once owned, due to the ensemble chorus.  For me, complex pitch
modulation, such as you get with a multiple delay line chorus, or three
or more oscillators, sounds much more ethereal than a 2 osc synth. 
However, there are variables beyond chorusing, such as filter type,
reverberation, and so on, that might be factors in "ethereal" sounds. 
Some people might argue that the meaty fatness of a Moog filter is
better for ethereal sounds than the clean precision of a Roland IR3109
filter, while others might argue the opposite.

Quite frankly, the most ethereal sounds I have ever heard are those that
come from the pure digital realm.  One of my first sounds in Csound was
a tone consisting of sine waves in octave relationship (e.g. x, 2x, 4x,
8x, 16x, 32x...), where each sine wave was ring modulated by a different
low frequency noise generator (the frequency of the noise rose with the
frequency of the sine wave).  Sounds like a whole orchestra playing one
note. Granular synthesis (synthesis where each sound is made up of
dozens to hundreds of smaller "grains" of sound) is also very good for
generating ethereal sounds.  If you have a Windows machine, try
Granulab; for Macs, there are several good granular synthesis programs
(I think Curtis Roads has written one), but look them up yourself
because I am a bitter PC owner who desperately wants a Mac so I can run
Metasynth, but can't justify buying another computer just to run a
single program.  Anyway, Csound and most other Music V type programs can
do granular synthesis.  Even the much maligned FM can create beautiful
ethereal wet textures, if you know how to program it.  Brian Eno used a
DX7 extensively for his ambient textures, while I have generated some FM
tones that are a dead ringer for ultra-slow filter sweeps on my beloved
Moog Rogue.

Anyway, hopefully my rambling helps to some degree.

Sean Costello



From kday at netcom.com  Thu Jan  7 19:21:22 1999
From: kday at netcom.com (Kevin Day)
Date: Thu, 07 Jan 1999 13:21:22 -0500
Subject: Tony Allgood's VCF PCB - parts list for US supplier?
Message-ID: <3694FB22.EB5E51@netcom.com>

Hello... 

I'm the happy owner of a bare VCF PCB courtesy of Tony Allgood, and I'm
about ready to order the parts for it.  Has anyone done this from a US
supplier such as Digi-Key?  It'd save me some work if you could email me
a list of part numbers :)

Thanks.

(the board looks _very_ nice, btw)

kevin

-- 
"sometimes I watch MTV just to see what I hate" - Blixa Bargeld



From Juergen.Haible at nbgm.siemens.de  Thu Jan  7 19:37:51 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 7 Jan 1999 19:37:51 +0100 
Subject: AW: AW: VC Phaser using the LM13600
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820117E954@nbgm336a.nbgm.siemens.de>


	[...]

	>The same inverse relationship applies to
	>the 4 x 135 degree notches. Both cases produce identical amplitude
	>responses (theoretically). I don't know how they compare in
practice,
	>but simulations using Electronics Workbench show identical results
when
	>the response is displayed with the Bode plotter.

Yes. You would see a difference for 5 (or any odd number of)
stages, however, because you have an inversion in each stage
in one case vs. the other.
If you add the direct signal normal and / or inverted you can
get both options with each topology. Same for the sign of the
feedback loop.
(Most phasers use an even number of stages anyway.)

JH.



From Mintlake at aol.com  Thu Jan  7 19:46:54 1999
From: Mintlake at aol.com (Mintlake at aol.com)
Date: Thu, 7 Jan 1999 13:46:54 EST
Subject: [AH] Odyssey VCO problem
Message-ID: <ee84be99.3695011e@aol.com>


In a message dated 1/7/99 11:16:21 AM, bmcdonald at chyron.com wrote:

<<Well, I'm still trying to fix my Odyssey (model 2800) VCO problem
(problem being that VCO 2 will not scale and its frequency range is much
different from 20Hz-20kHz - seems like it goes to like 40kHz, although I
didn't measure this).  I brought it to a local tech (Thang Ho at
Musicians Service Center in San Jose), who couldn't determine the exact
problem, but suggested that it may be the CD4011 chip (a quad NAND gate)
or the 2N5459 FET.  >>

Have you made sure that the 2nd voice CV is behaving normal?  If there is a
component failure in the VCO circuit causing what I am interpreting your
symptom to be, it could be the charge cap (heart of the VCO).  

Larry Church



From mirwin1 at istar.ca  Thu Jan  7 20:21:18 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Thu, 07 Jan 1999 14:21:18 -0500
Subject: AW: VC Phaser using the LM13600
References: <TFSEDRFU@idg.se>
Message-ID: <3695092E.49D5F30E@istar.ca>

Hello,
There should be no difference in the sound of a phaser using either
leading or lagging stages.
Consider a phaser made up of 4 leading (or lagging) simple all-pass
stages in series, with an output summing stage where the phase-delayed
signal is summed with the unmodified input signal. Assume the input
signal phase is zero degrees.  A reinforcement peak will be present at
the turnover freq ( total shift=360 degrees with a 90 degree
contribution from each stage). This is the case for both leading and
lagging stages. Two notches are present. If the turnover freq is
normalized to 1 the notches are at the following freqs :

    0.414 (4 x 45 degrees) and 2.414 (4 x 135 degrees) for leading and
lagging stages.

For the lagging stage case  the 4 x 45 degree notch is at 0.414 x
turnover freq while for the leading stage case  the 4 x 45 degree notch
is at 2.414 x turnover freq. The same inverse relationship applies to
the 4 x 135 degree notches. Both cases produce identical amplitude
responses (theoretically). I don't know how they compare in practice,
but simulations using Electronics Workbench show identical results when
the response is displayed with the Bode plotter.




From costello at seanet.com  Thu Jan  7 20:36:40 1999
From: costello at seanet.com (Sean Costello)
Date: Thu, 07 Jan 1999 11:36:40 -0800
Subject: Regarding DSP synths...
Message-ID: <36950CC8.64513C44@seanet.com>

Hi all:

This message just appeared on the Csound mailing list. If anyone is
interested in developing a hardware DSP synth, using Analog Devices'
XTCsound might be the way to go.  One warning: I've heard that the
performace of the current XTCsound evaluation board isn't that hot (i.e.
a 450 Mhz Pentium II running DirectCsound with no DSP board can
outperform the XTCsound on the evaluation board). However, they are
supposedly trying to iron out the bugs. Maybe the SHARC chips will be
used someday to produce a Nord Modular type device, that can also be
programmed in Csound, without the annoying hardware limitations of the
Nord (i.e. the Nord can't do any type of synthesis, like granular
synthesis, sampling, reverberation, etc. that requires delay memory).

Sean Costello

P.S.  I think that Scotty Vercoe is the son of Barry Vercoe, the MIT
Media Lab professor who originally developed Csound.

> Subject: RE: Linux Journal Csound article now on-line
> Date: Thu, 7 Jan 1999 13:57:06 -0500
> From: "Vercoe, Scotty" <Scotty.Vercoe at analog.com>
> To: Richard Dobson <rwd at cableinet.co.uk>
> CC: CSOUND <csound at maths.ex.ac.uk>
> 
> 
> I'm not one to start rumors but...
> 
> ADI has been making a multi-processor version of Extended Csound (XTCsound) for
> a customer.  It's fairly stable now, and our deadline is in a few months, so it
> should solidify soon.  I'm not sure when ADI will make these boards available to
> the public though.
> 
> For anyone using our card, we'll soon have a 32-bit driver that crashes much
> less.  I'll post a message when it's on our site.
> 
> Also, for a few of you who were interested in porting XTCsound to Linux (Mac
> anyone?), I will be getting a shipment of boards week after next (only 7 months
> late!!).  Send me a note if you're still interested in a free card.
> 
> thanks,
> Scotty Vercoe
> XTCsound Applications Consultant
> Analog Devices Software & Systems Technology Division
> Tel: (781) 461-3569       FAX: (781) 461-4291
> Support: Csound.support at analog.com
> Website: http://www.geocities.com/researchtriangle/thinktank/2138/



From jc at lynx.bc.ca  Thu Jan  7 21:20:14 1999
From: jc at lynx.bc.ca (jc)
Date: Thu, 7 Jan 1999 12:20:14 -0800 (PST)
Subject: gifs on diy
In-Reply-To:  <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>
Message-ID: <v04003a00b2ba523fe895@[209.82.89.91]>

I think this situation may have a little to do with the fact that pictures
tend to resurface over and over because of newcomers who seek the same info
that earlier memebers posted or requested ... since a lot of the
information is archived at individual sites maybe what we need is some kind
of links index, though I am not averse to receiving small GIF files (<50k)
once in a while ...

Here's a proposition: we can try to get everyone on the synth-DIY and
Analog lists to post their own and others' links to schematics archives and
then we can collate the info into a "pseudo-standard" link pages that can
be mirrored at anyone's page ... the info on this GIF-links page need only
specify basic info of image files stored at the link pointed to ...

With the inconvenience of having the lists flooded with house-keeping posts
for a few weeks we can flush out what's out there, round up the info and
make the accumulated information more readily available to all, especially
newcomers ... list members may include a link to this link page in their
SIG file whenever they post so that newbies can notice it without asking
openly for something they don't know exists ... a similar strategy seems to
have worked well with the Capacitor FAQ sheet, maybe we could even open up
a few different categories like (i) synth-DIY, (ii) vacuum-tube DIY and
(iii) Sound Processing (effects) DIY GIF/JPG links ...

my CDN 0.02$
jc

>so it would make sense to loosen the rules a little.
>So I don't want this to be a "don't post pictures" post. But we
>should find a general rule about pictures, IMO. At least a size
>limit.
>
>What do you think ?
>
>JH.






From gmuir at sympatico.ca  Thu Jan  7 22:14:27 1999
From: gmuir at sympatico.ca (Gavin Muir)
Date: Thu, 7 Jan 1999 16:14:27 -0500
Subject: Strange source for SSM2040 ICs?
Message-ID: <199901072115.QAA11621@smtp13.bellglobal.com>

Hi all,

	This is my second posting, so before I get to the point, thanks to those
who wrote in regards to my question on the SSM2040 and 2020 circuits.

	On this same track, I performed a search awhile back and noticed that
there is a catalogue offering SSM 2040 Ics (incorrectly labelled as a VCO,
but corrected elsewhere as a VCF). On a hunch I picked one up (along with a
2020), and was a bit surprised at what I got. 

	Apparently Thomas Organs used to do some contract work for Moog or
something, and somehow the SSM chips eventually got used in some of their
products. What I got was a clearly marked SSM 2020, but also an oddly
marked IC with a Thomas parts number on it - 5099. I phoned and asked about
this, and apparently this is supposed to be a 2040, only it has been
screened with the Thomas parts number instead of the usual SSM2040. I don't
really have a circuit to test these in (I'm not putting this in a
synthesizer to test it thank you!),  so I was just wondering whether or not
anyone else had found this site or tested one of these chips? Is it fairly
normal for such chips to be re-screened by a manufacturer? Any ideas on a
quick circuit which I could use to test this IC?

Cheers,
Gavin Muir 

P.S. I'm still looking for a basic VCA circuit for the 2020 if anyone can
point me towards one!




From oakley at techrepairs.freeserve.co.uk  Thu Jan  7 22:17:07 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Thu, 7 Jan 1999 21:17:07 -0000
Subject: AW: VCO-1C #2
Message-ID: <009901be3a83$6b534a60$f522883e@default>

Ingo wrote:
I'm asking because in my selfmade poly synth (without autotune) nine of
the ten 3340s are pretty stable, after a warm up time of 20 minutes or
so. But one is drifting very much. I thought that one had gone bad, but
maybe I just had luck with the other nine?

Tony writes:
Me too. I have two bad ones out of 16 VCOs. I replaced the really bad
one with another and I think its liveable with. I have just been mailed
by someone, Colin F I think, who said that Roland selected their CEMs
for the Jp8. I don't know whether thats true, but some 3340s are better
than others. They will always be fine for a mono, it is as you say, a
real bummer in a poly. I actually reduced my 8-voice to four because I
was fed up with retuning each VCO before a gig. Funny thing was I used
to have internal trimmers only until I had to gig with the thing. Then I
put them all on the front.

However, I must say that after 30 minutes any drift seems to have
stopped. But my Poly will soon be undergoing a major rehouse, with a new
front panel from Germany and internal MIDI.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From brucejd at interlog.com  Thu Jan  7 22:31:45 1999
From: brucejd at interlog.com (Bruce Duncan)
Date: Thu, 7 Jan 1999 16:31:45 -0500 (EST)
Subject: Bulk Pot order
Message-ID: <199901072131.QAA04634@smtp.interlog.com>

Hi,


Would anybody be interested in contributing to a bulk order of 50K
potentiometers
The ones I want to order are identical to the Mouser 16mm Miniature Carbon
Composition part 31JN405 on page 192 of their cataloge (depending on which
issue you have).
They aren't the best pots available but I have found them excellent for
general use
and have them in projects that are 3 years old with no problems. The body of
the pot is not
too small but allows for 1 inch (25mm) spacing between pots. The metal shaft
style is round with no flats or grooves (ideal for knobs with set screws)
.25inches or 6mm in diameter X .5inches or 12mm long. The panel hole size is
9/32"(7.2mm) and will work on panels up to 1/8th inch (3.17mm)thick
I would like to keep the minimum order to 100 pieces per person
and the cost would be $0.47US per pot. plus postage which on 100 should be
about $6.00 to the US
Mouser sells them for $1.27 each or $0.87 if you get 100 or more.

Let me know if you are interested and we can go from there.

Bruce
 






From uzs159 at uni-bonn.de  Thu Jan  7 23:24:31 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Thu, 07 Jan 1999 23:24:31 +0100
Subject: gifs on diy
In-Reply-To: <v04003a00b2ba523fe895@[209.82.89.91]>
References: < <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>
Message-ID: <3.0.5.32.19990107232431.008a1100@ibm.rhrz.uni-bonn.de>

At 12:20 07.01.99 -0800, you wrote:
>I think this situation may have a little to do with the fact that pictures
>tend to resurface over and over because of newcomers who seek the same info
>that earlier memebers posted or requested ... since a lot of the
>information is archived at individual sites maybe what we need is some kind
>of links index, though I am not averse to receiving small GIF files (<50k)
>once in a while ...

Yes it should not be common to receive 20 gifs of 50k size.
There is something to say about images:
If we would restrict ourselves to images with only 16 colors and only in 
gif format we could spice up the otherwise excellent discussions with
smaller images, without wasting too much bandwidth.
My personal idea is that the sender must try to conserve bandwidth as much
as possible. A file greater than 50k is better suited to be put on a
web-server.
And don't forget the possibility that another one might put it up somewhere, 
if the sender doesn't do a webpage.

>Here's a proposition: we can try to get everyone on the synth-DIY and
>Analog lists to post their own and others' links to schematics archives and
>then we can collate the info into a "pseudo-standard" link pages that can
>be mirrored at anyone's page ... the info on this GIF-links page need only
>specify basic info of image files stored at the link pointed to ...

Basically this is the Idea of Martin Czechs "Unofficial DIY Archive"
All posts are archived in certain intervals, and there is a list of URLs of
listmembers as well. Martin did check all the links if they are working!!

my 0.02 EUR



             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From ben at stuyts.nl  Thu Jan  7 23:47:58 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Thu,  7 Jan 99 23:47:58 +0100
Subject: gifs on diy
In-Reply-To: <3694C74B.C34673D8@cc.u-szeged.hu>
References: <1BF5E20E0C4DD111BBAB00805FE2D58201151D38@nbgm336a.nbgm.siemens.de>
	<3694C74B.C34673D8@cc.u-szeged.hu>
Message-ID: <199901072248.XAA09404@daneel.stuyts.nl>

On Thu, 07 Jan 1999, Beszedes Arpad wrote:

> Haible Juergen wrote:
>
> > for *everyone* who is subscribed, not only the ones particularly
> > interested in the pictures.
> >
>
> Well, this is not completely the truth, because one can disable in the
> mailing program downloading messages greater than some limit. Eg. in
> Netscape Messanger: Preferences/Disk space.

Not true either. Remember, all the mail has to be distributed over the  
internet anyway to the various mail servers, so it takes up bandwidth and disk  
space. Also, I get my mail over UUCP, so all mail is downloaded, whether I  
want it or not.

> Say, 50kbytes would be okay?

We're talking about black & white GIF's of schematics, so 20 KB should be  
more than enough. Above that, I'd prefer that people put it on a web/ftp site.

Best regards,
Ben



From b.layer at vikingelectronics.com  Thu Jan  7 23:59:41 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 07 Jan 1999 16:59:41 -0600
Subject: Bulk crack order
Message-ID: <3.0.6.32.19990107165941.007cc440@192.168.210.18>

Just kiddin.





From ben at stuyts.nl  Fri Jan  8 00:37:30 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri,  8 Jan 99 00:37:30 +0100
Subject: DSP Stuff: floating point or fixed point
In-Reply-To: <3.0.5.32.19990106234640.007cab40@popd.ix.netcom.com>
References: <3.0.5.32.19990106234640.007cab40@popd.ix.netcom.com>
Message-ID: <199901072337.AAA09436@daneel.stuyts.nl>

On Wed, 06 Jan 1999, Michael Maloney wrote:

> Obviously the floating point stuff allows you to skip a few steps (e.g.
> re-scaling), but the 21061 ezkit lite also comes with a "light" version of
> the G21K C compiler...as I recall it was about $300.00.  I'm ashamed to say
> that mine is still in the box, so I can't comment on its noise levels.

I happened to read a couple of messages on comp.dsp about how a fixed point  
DSP might be actually preferable over a floating point DSP. Here are some  
quotes:

> From: chris at bores.com (Chris Bore)
> Newsgroups: comp.dsp
> Subject: Re: The best DSP for digital audio
> Date: Mon, 04 Jan 1999 15:18:41 GMT
> Message-ID: <3691d3e5.21289755 at news.globalnet.co.uk>
...
> 1) Floating point operation modulates the noise floor in a signal
> dependent way. Floating point parts automatically scale and normalise
> each number as it is processed. This means that the noise floor is
> modulated in a signal-dependent way. It can be shown that the noise
> floor is always less than that of a fixed point device with same
> mantissa length - but some people claim the modulation of the noise
> floor is audible. With fixed point devices the programmer has control
> of normalisation and scaling - so these devices may be preferred for
> digital audio.

And:

> From: Randy Yates <yates at shadow.net>
> Newsgroups: comp.dsp
> Subject: Re: The best DSP for digital audio
> Date: Tue, 05 Jan 1999 20:15:24 -0600
> Message-ID: <3692C73C.89C2623F at shadow.net>
> Reply-To: yates at ieee.org
...
> For operations such as FIR filtering, a fixed-point part has
> GREATER precision (i.e., LESS noise) than a floating-point
> device. This is because all fixed-point processors (that I've
> ever seen, at least) that operate on N-bit data provide at
> least a 2N-bit accumulator. For example, even a lowly 16-bit
> fixed-point device such as the TI TMS320C50 has a 32-bit
> accumulator. Thus one can carry forward 32 bits of precision
> in the sum involved in the filter convolution, and if
> noise-shaping is used, one can preserve much of that precision
> when converting back to 16-bit values.
>
> As you have already alluded to, the (32-bit) floating-point part
> is "stuck" at 24 bits of precision, i.e., that afforded by
> its mantissa, and I would venture a guess that a 16-bit
> value that has been properly noise-shaped from a 32-bit
> result is going to sound better than a 24-bit result with
> no noise shaping.
>
> If we up the fixed-point ante to the 56/24 architecture afforded
> by the Motorola 56k, then there's no more comparison to be had,
> because we have as a result 24-bit samples that have been
> noise-shaped from 56-bit accuracy.
>
> People, get the idea out of your head that floating point == more accuracy!

I thought that was interesting.

Best regards,
Ben



From DrXex at aol.com  Fri Jan  8 00:44:12 1999
From: DrXex at aol.com (DrXex at aol.com)
Date: Thu, 7 Jan 1999 18:44:12 EST
Subject: Hello AH
Message-ID: <26ee2fbc.369546cc@aol.com>

My former email address was DinedHavoC at aol.com
Its now DrXex at aol.com

On a more analog note...
anyone got some tips n tricks for a SCI Pro One?
~Xex. Dr. Xex.~

PS- someone send me subbing info for Digital Hell please?



From magnus at analogue.org  Fri Jan  8 00:45:43 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 08 Jan 1999 00:45:43 +0100
Subject: Digital DIY synths?
In-Reply-To: Your message of "Thu, 07 Jan 1999 23:52:09 -0800"
References: <3695B929.5E9D@swipnet.se>
Message-ID: <199901072345.AAA20997@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 FA> Did you read Magnus answer? We should bang not two rocks, we should bang two
 FA> symphonic orchestras...
 >> 
 >> Right, is this what they call "Orchestra hit"?

 B> Yes , when you hit the orcestra on the heads!!

Don't you?

Also, this is how I keep the percussionist happy, he get extra money
for hitting the other orchestra members for me so I don't have to.
We have even made it a solo number for him... hillarious!
 
 FA> The first violinist will say: "ooh, it's only a scratch..."
 >> 
 >> ... and here is the machine that goes BING!

 B> ...And here is the swedish preminister!!
 B> ooh noo, Mr Kreosot!!!

Bring me another bucket!

This is BTW where the Bucket-Brigade (BBD) comes from.

Oh, no, not a leaf-thin mint chocolate!

KABOOOM!!!

[The explotion and sudden death of a very fat man.]

Somewhere I _think_ we have gotten a bit off-topic ;^)

Cheers,
Magnus



From gmuir at sympatico.ca  Fri Jan  8 00:56:03 1999
From: gmuir at sympatico.ca (Gavin Muir)
Date: Thu, 7 Jan 1999 18:56:03 -0500
Subject: Strange source for SSM2040 ICs?
Message-ID: <199901072358.SAA29205@smtp11.bellglobal.com>

Hi BJ,

> Whats the name and URL for the catalogue?
> It might be a source for SSM2040 VCF's
> 
> BJ

	Well, hopefully I'm not getting hopes up for nothing (as apparently nobody
other than the supplier can confirm that the part I got is the now infamous
2040), however I see no reason why it wouldn't be. They also have 2020s and
2050s. Check the IC section out though for any other bizarre chips out
there (lotsa weird rhythm generator LSIs etc.)

	The URL is www.mitatechs.com/thomas.html. 

	They have a lot of oddball parts for organs and other tidbits. I  feel
weird though, as if I could find this with a search engine, anybody could
(or should) have too. The SSMs are $30 US each plus shipping. Now, if I can
just put together a quickie external circuit to test this puppy and confirm
its identity!! 

	I guess I'm just paranoid, as it seems like a bit of a dream to find such
a rare item for a mere $30. Also, I was romantically  looking forward to
seeing the glorious SSM2040 plastered on the top of the chip. But if it's
the one, who cares about the numbers on the lid!




From magnus at analogue.org  Fri Jan  8 02:51:48 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 08 Jan 1999 02:51:48 +0100
Subject: AW: VC Phaser using the LM13600
In-Reply-To: Your message of "Fri, 08 Jan 1999 01:47:36 -0800"
References: <3695D438.13E@swipnet.se>
Message-ID: <199901080151.CAA00769@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

Hi!

I just thought someone would jump on this one... ;)

 B> Magnus Danielson wrote:
 >> As for lead/lag - you can't break the casuallilty without getting into
 >> trouble with Einstein. There have been some trouble regarding how low
 >> intensity (photon per photon) interferometers actually work with this
 >> respect and the best explanation comes from the transaction
 >> description of this interaction. Also, further trouble have been in
 >> the discussions of how fast a jump over a barriers (such as in a
 >> tunnel diod) actually takes, there are people discussing speeds in
 >> superluminar levels (that is, _faster_ than light). In Germany they
 >> had some fun and sent Mozart at 4.5 times the speed of light, without
 >> any noticable distorsion over a distance of 11 cm. Hope this is
 >> confusing ;)
 >> 
 >> Cheers,
 >> Magnus

 B> Well , isn't that infact to get in trouble with Einstein?
 B> Since he said, at the speed of light the time is still!!
 B> Or iam lost in space?

Well, this is a bit confusing... Einstein said that nothing could
travel faster than light and that due to time dilation time would
stand still... well, dependent on the reference frame ofcoarse.

The problem that I refered to, the interferometer, where announced by
Richard Feynman (Nobel lautherate in physics for quantum
electrodynamics - which he claimed that no one understands!) as one of
the big mysterious that no one understands. The problem is that even
when you pass a single photon through the interferometer it will
suddenly behave as a wave and interfer with itself and suddenly
reappear as a photon for the photo-multipliers set out there. This is
odd since the photon (as seen as a particle) could only take on one
passage of the two possible (there is two slits). The handshaking of
which way to take will happen at light speed, while the time stays
still for us observers... hmm. I think I got that right. It is a bit
confusing, but you have to accept waves going backwards in time and
so. This is allowed by the Schroedinger equation, but we are just used
to do them in one direction. This also happends over impossible
barriers, where a photon or electron may tunnel over. They have done
this with lasers and microwaves. There are several interesting
articles online on this. There are some less-serious or less-valid
things to this... as you might imagine. Check out the FTL FAQ for
instance: http://hepweb.rl.ac.uk/ppUK/PhysFAQ/FTL.html

It is most annoying, but it seems to hold as far as I can tell.

 B> BJ
 B> (who practises Einsteins "relativ'ely" theory all the tima at the speed
 B> of light in my bed!!) :)

You got a mighty fast bed I hear...

Cheers,
Magnus



From magnus at analogue.org  Fri Jan  8 03:04:05 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 08 Jan 1999 03:04:05 +0100
Subject: BJ's 4046 oscillator
In-Reply-To: Your message of "Fri, 08 Jan 1999 01:52:52 -0800"
References: <3695D574.929@swipnet.se>
Message-ID: <199901080204.DAA00890@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 >> Magnus Danielson wrote:
 >> >>
 >> >> Hi!
 >> >>
 >> >> It just truck me that there is more to BJs 4046 oscillator.
 >> >>
 >> >> >From the two buffer op-amps comes two waveforms that look like this
 >> >>
 >> >> 0 V -   ---   ---   ---   ---
 >> >> \  |  \  |  \  |  \  |
 >> >> \ |   \ |   \ |   \ |
 >> >> \|    \|    \|    \|
 >> >>
 >> >> 0V   ---   ---   ---   ---   -
 >> >> |  \  |  \  |  \  |  \  |
 >> >> |   \ |   \ |   \ |   \ |
 >> >> \|    \|    \|    \|    \|
 >> >>
 >> >> Adding them creates a saw, but subtracting them and you got yourself a
 >> >> triangle. Using the saw+square trick you can have a sawtooth of the
 >> >> same frequency as the triangle, and they are in phase. A deglitching
 >> >> is assumed ofcourse.
 >> >>
 >> >> Cheers,
 >> >> Magnus
 >> 
 B> Sorry, but the waves looks like this:
 >> 
 B> /|        /|        /
 B> / |       / |       /
 B> /  |      /  |      /
 B> 0V-----/   |-----/   |-----/
 >> 
 B> /|        /|        /|
 B> / |       / |       / |
 B> /  |      /  |      /  |
 B> 0V/   |-----/   |-----/   |-----

[Big fat hand slaming an obviuosly empty head...]

I was obviously tired when I wrote this, so sorry.

The point was that the spaced-saw waves where 180 degrees out of
phase, that I happend to get them in wrong polarity was due to a empty
and tired head.

 B> Therefore the final sawtoth wave is twice in
 B> frequecy of the sqare wave available at pin 3 .
 >> 
 B> A nother nice thing with this design is the ability to get PWM
 B> by the usage of the Xor gate.It generates 100% PWM, no need for
 B> external comparator.infact one can get PWM and Ring mod at the same time
 B> from the same Xor gate.
 >> 
 B> In wich way did you have in mind to do the saw to tri conversation?
 B> Im not so sure that you relly get a nice and clean tri wave due to the
 B> "out of phase" acting by each saw! If one would phase reverse one of the
 B> waves then you might get a tri! I have to try to see!

 B> BJ 
 B> again

Well, in the normal saw-to-tri case you would extract such a spaced
sawtooth that you then subtract with the saw (in a 1:2 mix) to get a
triangle. Here you allready got the spaced saws, so it is only
subtract these to each other.

Infact, the diff-voltage over the capacitor has a triangle shape, so
setting up an op-amp as a diff-amp (using the existing buffer amps in
BJs schematic) is a simple matter of a op-amp and a few resistors.

I even think that this might be a better solution than a normal
saw-to-tri converter.

I will try it out, I have all the stuff around.

Cheers,
Magnus



From jhaible at primus-online.de  Fri Jan  8 03:25:25 1999
From: jhaible at primus-online.de (jhaible)
Date: Fri, 8 Jan 1999 03:25:25 +0100
Subject: VC Phaser using the LM13600
Message-ID: <19990108022833.11743.qmail@nuernberg2.pop.metronet.de>

> A phase shifter circuit really has no delay, above or below the center
> frequency.  It just shifts the phase.  This is important: any change
> at the input of a phase shifter will always show up in the output
> immediately.

At least *something* will show up in the output immediately. But the
shape of your input will be altered, as different spectral components of
your
input signal will get different delay. That's how I think it works, at
least.
The concept of group delay is difficult to apply to real world signals, as
the d phi / df at a certain frequency asumes a sine signal that was
switched on a long time before. Nevertheless it has some relation to
finite, real life signals, too. Think of a burst of several cycles of a
certain
frequency - the group delay should be seen at least approximately.
Or think of the response to a input step - the change in shape at the
output resembles the (different) delay for each frequency component
of the input step.
Another argument that a "real" delay is involved in all pass filters:
You can make a nice vibrato just with a variable all pass filter. Just
as in a BBD, you can get positive and negative frequency deviation
because there is some delay to "store" the signal for a short time.

JH.



From magnus at analogue.org  Fri Jan  8 04:19:25 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 08 Jan 1999 04:19:25 +0100
Subject: VC Phaser using the LM13600
In-Reply-To: Your message of "Fri, 8 Jan 1999 03:25:25 +0100"
References: <19990108022833.11743.qmail@nuernberg2.pop.metronet.de>
Message-ID: <199901080319.EAA01311@mail2.it.kth.se>

>>>>> "j" == jhaible  <jhaible at primus-online.de> writes:

 >> A phase shifter circuit really has no delay, above or below the center
 >> frequency.  It just shifts the phase.  This is important: any change
 >> at the input of a phase shifter will always show up in the output
 >> immediately.

 j> At least *something* will show up in the output immediately. But the
 j> shape of your input will be altered, as different spectral components of
 j> your
 j> input signal will get different delay. That's how I think it works, at
 j> least.
 j> The concept of group delay is difficult to apply to real world signals, as
 j> the d phi / df at a certain frequency asumes a sine signal that was
 j> switched on a long time before. Nevertheless it has some relation to
 j> finite, real life signals, too. Think of a burst of several cycles of a
 j> certain
 j> frequency - the group delay should be seen at least approximately.

Well... there are two types of delay, phase delay and group delay.

If phi(w) is the phase responce of a network...

Phase delay is the delay of a single sine signal, the phase delay is

         phi(w)
tau(w) = ------
           w

Group delay is the delay of a packet of nearby frequencies, the group
delay is

       d phi(w)
D(w) = --------
         d w

Who every said things where simple?

 j> Or think of the response to a input step - the change in shape at the
 j> output resembles the (different) delay for each frequency component
 j> of the input step.
 j> Another argument that a "real" delay is involved in all pass filters:
 j> You can make a nice vibrato just with a variable all pass filter. Just
 j> as in a BBD, you can get positive and negative frequency deviation
 j> because there is some delay to "store" the signal for a short time.

Yes, but while delay is a linear property, this is infact not a linear
property since a lineary network should be time invariant which the
allpass obviously isn't since you modulate it.

On the other hand, synths becomes sooooo boring when they are truely
linear... no VCA, VCF, no envelope, only unstable sine oscillators etc.
Be happy and slightly nonlinear ;)

Cheers,
Magnus




From theremin1 at worldnet.att.net  Fri Jan  8 04:50:13 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Thu, 7 Jan 1999 19:50:13 -0800
Subject: gifs on diy
Message-ID: <001f01be3ab9$ffa95200$d9784e0c@hpcustomer>

Yes!  most schematic gifs don't take too much, anyway!

-Art

-----Original Message-----
From: James Jackson <james at newd.demon.co.uk>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 5:42 AM
Subject: gifs on diy


>>Now speed and bandwidth surely have improoved meanwhile,
>>so it would make sense to loosen the rules a little.
>>So I don't want this to be a "don't post pictures" post. But we
>>should find a general rule about pictures, IMO. At least a size
>>limit.
>
>How about a 5-10KB size limit?
>
>-JJ
>---------------------------------------------------------------------------
----
>James Jackson - New Era Web Designs
>          |
>          ------------------- james at newd.demon.co.uk
>Sales ------------------- sales at newd.demon.co.uk
>Information ------------ info at newd.demon.co.uk
>
>Website ---------------- http://www.newd.demon.co.uk
>---------------------------------------------------------------------------
----
>
>




From aschrock at cs.brandeis.edu  Fri Jan  8 05:56:58 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Thu, 7 Jan 1999 23:56:58 -0500 (EST)
Subject: Strange source for SSM2040 ICs?
In-Reply-To: <199901072358.SAA29205@smtp11.bellglobal.com>
Message-ID: <Pine.SGI.3.95.990107235258.16045A-100000@peridot.cs.brandeis.edu>

Is $30 really that big a steal for a 2040? Or maybe just finding them is a
trick unto itself? Just curious, I got one in a box with some CEMs and was
wondering if it's worth that much. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|

On Thu, 7 Jan 1999, Gavin Muir wrote:
> 	They have a lot of oddball parts for organs and other tidbits. I  feel
> weird though, as if I could find this with a search engine, anybody could
> (or should) have too. The SSMs are $30 US each plus shipping. Now, if I can
> just put together a quickie external circuit to test this puppy and confirm
> its identity!! 
> 
> 	I guess I'm just paranoid, as it seems like a bit of a dream to find such
> a rare item for a mere $30. Also, I was romantically  looking forward to
> seeing the glorious SSM2040 plastered on the top of the chip. But if it's
> the one, who cares about the numbers on the lid!




From qfulsom at usa.net  Fri Jan  8 06:41:16 1999
From: qfulsom at usa.net (Quint)
Date: Thu, 7 Jan 1999 23:41:16 -0600
Subject: Strange source for SSM2040 ICs?
Message-ID: <000b01be3ac9$836dc800$622e5380@s8p8t9>

Yep its them all, in fact they were $10-20 before synthtech went up!  Still
not a bad price if you need them.

-----Original Message-----
From: Gavin Muir <gmuir at sympatico.ca>
To: <zzynt at swipnet.se>
Cc: <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 7:09 PM
Subject: Re: Strange source for SSM2040 ICs?


>Hi BJ,
>
>> Whats the name and URL for the catalogue?
>> It might be a source for SSM2040 VCF's
>>
>> BJ
>
> Well, hopefully I'm not getting hopes up for nothing (as apparently nobody
>other than the supplier can confirm that the part I got is the now infamous
>2040), however I see no reason why it wouldn't be. They also have 2020s and
>2050s. Check the IC section out though for any other bizarre chips out
>there (lotsa weird rhythm generator LSIs etc.)
>
> The URL is www.mitatechs.com/thomas.html.
>
> They have a lot of oddball parts for organs and other tidbits. I  feel
>weird though, as if I could find this with a search engine, anybody could
>(or should) have too. The SSMs are $30 US each plus shipping. Now, if I can
>just put together a quickie external circuit to test this puppy and confirm
>its identity!!
>
> I guess I'm just paranoid, as it seems like a bit of a dream to find such
>a rare item for a mere $30. Also, I was romantically  looking forward to
>seeing the glorious SSM2040 plastered on the top of the chip. But if it's
>the one, who cares about the numbers on the lid!
>




From don at till.com  Fri Jan  8 06:46:06 1999
From: don at till.com (Don Tillman)
Date: Thu, 7 Jan 1999 21:46:06 -0800 (PST)
Subject: Phase vs. Delay (was VC Phaser using the LM13600)
In-Reply-To: <19990108022833.11743.qmail@nuernberg2.pop.metronet.de>
	(jhaible@primus-online.de)
Message-ID: <199901080546.VAA24364@shell9.ba.best.com>

   From: "jhaible" <jhaible at primus-online.de>
   Date: Fri, 8 Jan 1999 03:25:25 +0100

   Don:
   > A phase shifter circuit really has no delay, above or below the center
   > frequency.  It just shifts the phase.  This is important: any change
   > at the input of a phase shifter will always show up in the output
   > immediately.

   At least *something* will show up in the output immediately. But
   the shape of your input will be altered, as different spectral
   components of your input signal will get different delay. That's
   how I think it works, at least.

Well, let's see...  Imagine a single phase shift stage in front of
you, the classic opamp circuit.

At low frequencies you'll have near 0 degrees phase shift, there's no
delay because the signal goes straight through.

At high frequencies there's 180 degrees phase shift.  Well not exactly
phase shift; it's a straightforward polarity inversion.  No delay
there either.

At the center frequency there's 90 degrees phase shift (-90 actually),
but this happens instantaneously -- it's computed from the derivative
of the the signal (or integral, depending the circuit).  That happens
instantly in the same way the you can find the slope of a curve
instantly.  So there's no delay there either.

At any point in between it's just a mix of the above three signals.
Thus no actual delay.

   Another argument that a "real" delay is involved in all pass filters:
   You can make a nice vibrato just with a variable all pass filter. Just
   as in a BBD, you can get positive and negative frequency deviation
   because there is some delay to "store" the signal for a short time.

Good argument!  It's certainly true that a phase shift circuit makes a
fine vibrato.  But I'll claim that that this vibrato effect happens
because the phases of the component sines are changing and not because
of any Doppler-like pitch shift due to storing the signal in a medium
and pulling it out at a different rate.

  -- Don




From cyborg0 at GlobalEyes.net  Fri Jan  8 07:05:03 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 08 Jan 1999 00:05:03 -0600
Subject: Arp Oddy VCO 2 trubbles..
Message-ID: <3695A00F.648CC10E@globaleyes.net>

Well, I have investigated this strange vco 2 problem.. and I have come
up with a few speculative reasons why its always just VCO 2 crapping out
and why vco 1 is usually unaffected..

1)on the schematics you have the second voice CV porting into the vco 2
CV buss.VCO 1 doesnt have this connection

2)VCO 2 also has the sync connection coming from VCO 1.. This is a
potential, but unlikely culprit..

Now, mind you, I have had problems before with that second voice CV
circuit AND the keyboard trigger processor. they act together to
allocate the second cv from the keyboard to VCO 2. I would say that if
you suspect this to remove R57 on board B. This disconnects the second
voice CV from the CV buss of VCO 2..  (boy, that was a mouthful) 

NEway, removing r57 will isolate CV #2 from VCO 2. If it works ok then,
you know it has something to do with the sample and hold circuit (i
think) they use to hold the second CV.. Its drooping or whatever. 

As for myself, I am prlly just going to disconnect the second voice CV
AND the main CV from vco2 and rig it up so I can have each vco playing
seperate melodies on my Oddy by using one midi/cv channel on each vco.
At least that way then, I dont have to worry about it anymore. Let it be
broke already! :))

OH, BTW, I just realized that you could make VCO 2 into an LFO just like
vco 1 very easily.. This could be cool if you run a lot of stuff through
it..and you could make vco 1 sync to vco2 kinda easily.. wow..Lots o
neat stuff going on here..

Oh well, I will cease my brain droppings.. :)

Rob



From qfulsom at usa.net  Fri Jan  8 07:07:11 1999
From: qfulsom at usa.net (Quint)
Date: Fri, 8 Jan 1999 00:07:11 -0600
Subject: DSP Stuff
Message-ID: <002f01be3acd$222f8980$622e5380@s8p8t9>

TI has unbelievable support for their development products and I usually see
c54x dev. kits (www.ti.com/sc/details52) with software as cheap as $100 with
coupon or $150 flat out.  The materials available are unreal for all TI
stuff, cd or book of all data FREE!  Their new c6000 is just unreal.  Its
kit is $1k - $1.5k.  This is a totally different best though.  The COOLEST
thing is their new analog devices, such as the MSP's or mixed-signal
processor that take dsp output to analog output!  They have conferences for
free I believe bi/years? as well as deelopment contest.  Check it out.
Coupons are usually available in EE times and such.

Also if you on a quest with a budget don't forget that what started the
craze was apples usage for programmable lucent dsp's in the 660, 880 av
(audiovisual) series you can now pluck up from $150-$300, giving you a
programmable dsp, realtime input & output (hard disk recording) of audio &
video.
They was also an early ppc version 601's but I think 6600,8800? which also
are very cheap.  This is a great way to go if your just learning.

Quint


-----Original Message-----
From: Martin J Keefe <martink at cix.co.uk>
To: <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 10:57 AM
Subject: Re: DSP Stuff



> Nope.. this is also the misconception I had.. its not actually a SHARC..
> The devkit for the SHARC is about  1k dollars... Although, the ezkit

There is a SHARC EZ-KIT (has an ADSP-21061 on it). I got mine from Maplin
in the UK for about ?160. Haven't had much time to play with it yet. The
chip itself is definitely NOT a DIY item -- 100s of the tiniest surface
mount legs I've seen, spaced very close together.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk




From zzynt at swipnet.se  Fri Jan  8 08:52:09 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 07 Jan 1999 23:52:09 -0800
Subject: Digital DIY synths?
References: <78OoQbVpHFB@fa.camelot.de> <199901071706.SAA17936@mail2.it.kth.se>
Message-ID: <3695B929.5E9D@swipnet.se>

Magnus Danielson wrote:
> 
> >>>>> "FA" == Florian Anwander <fa_diy at fa.camelot.de> writes:
> 
>  FA> Hello Ben,
>  >> Switches? You had switches? Man, we had to bang two rocks together to get any
>  >> sound and use lightning for special effects. And we were grateful for it.
> 
>  FA> Did you read Magnus answer? We should bang not two rocks, we should bang two
>  FA> symphonic orchestras...
> 
> Right, is this what they call "Orchestra hit"?

Yes , when you hit the orcestra on the heads!!
 
> Used to be such a common sample, but maybe there is no more orhestras
> to hit...
> 
>  >> I feel a Monty Python thread coming up...
> 
>  FA> The first violinist will say: "ooh, it's only a scratch..."
> 
> ... and here is the machine that goes BING!

...And here is the swedish preminister!!
ooh noo, Mr Kreosot!!!

BJ



From zzynt at swipnet.se  Fri Jan  8 08:53:31 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 07 Jan 1999 23:53:31 -0800
Subject: Strange source for SSM2040 ICs?
References: <199901072115.QAA11621@smtp13.bellglobal.com>
Message-ID: <3695B97B.6E1F@swipnet.se>

Gavin Muir wrote:
> 
> Hi all,
> 
>         This is my second posting, so before I get to the point, thanks to those
> who wrote in regards to my question on the SSM2040 and 2020 circuits.
> 
>         On this same track, I performed a search awhile back and noticed that
> there is a catalogue offering SSM 2040 Ics (incorrectly labelled as a VCO,
> but corrected elsewhere as a VCF). On a hunch I picked one up (along with a
> 2020), and was a bit surprised at what I got.
> 
>         Apparently Thomas Organs used to do some contract work for Moog or
> something, and somehow the SSM chips eventually got used in some of their
> products. What I got was a clearly marked SSM 2020, but also an oddly
> marked IC with a Thomas parts number on it - 5099. I phoned and asked about
> this, and apparently this is supposed to be a 2040, only it has been
> screened with the Thomas parts number instead of the usual SSM2040. I don't
> really have a circuit to test these in (I'm not putting this in a
> synthesizer to test it thank you!),  so I was just wondering whether or not
> anyone else had found this site or tested one of these chips? Is it fairly
> normal for such chips to be re-screened by a manufacturer? Any ideas on a
> quick circuit which I could use to test this IC?
> 
> Cheers,
> Gavin Muir
> 
> P.S. I'm still looking for a basic VCA circuit for the 2020 if anyone can
> point me towards one!

Whats the name and URL for the catalogue?
It might be a source for SSM2040 VCF's

BJ



From irish at eskimo.com  Fri Jan  8 09:44:59 1999
From: irish at eskimo.com (Irish)
Date: Fri, 8 Jan 1999 00:44:59 -0800
Subject: gifs on diy
References: <1.5.4.32.19990107125058.006734d0@pop3.demon.co.uk>
Message-ID: <99010800474508.10364@Pandemonium>

On Thu, 07 Jan 1999, James Jackson typed:
>>Now speed and bandwidth surely have improoved meanwhile,
>>so it would make sense to loosen the rules a little. 
>>So I don't want this to be a "don't post pictures" post. But we
>>should find a general rule about pictures, IMO. At least a size
>>limit. 
>
>How about a 5-10KB size limit?
>
It is possible to impose a size limit in some Mailing List software - on one of
the dev lists I run I occasionally get "Hey, this 250k file I tried to post
bounced!" and I always respond "Good." :) 

Irish 



From irish at eskimo.com  Fri Jan  8 09:48:00 1999
From: irish at eskimo.com (Irish)
Date: Fri, 8 Jan 1999 00:48:00 -0800
Subject: DSP Stuff
References: <memo.19990107155654.262C@martink.compulink.co.uk>
Message-ID: <9901080052130A.10364@Pandemonium>

On Thu, 07 Jan 1999, Martin J Keefe typed:
>
>There is a SHARC EZ-KIT (has an ADSP-21061 on it). I got mine from Maplin 
>in the UK for about ?160. Haven't had much time to play with it yet. The 
>chip itself is definitely NOT a DIY item -- 100s of the tiniest surface 
>mount legs I've seen, spaced very close together.

Maybe not DIY for *you* :) but I'll bet not everyone has a Metcal either (or a
couple of years SMT rework experience). 

If it's a kit, how are you supposed to mount the IC? Or does it come already
soldered onto the board? 

Irish



From irish at eskimo.com  Fri Jan  8 09:53:06 1999
From: irish at eskimo.com (Irish)
Date: Fri, 8 Jan 1999 00:53:06 -0800
Subject: Strange source for SSM2040 ICs?
References: <199901072115.QAA11621@smtp13.bellglobal.com>
Message-ID: <9901080108070C.10364@Pandemonium>

On Thu, 07 Jan 1999, Gavin Muir typed:
>Hi all,

>	Apparently Thomas Organs used to do some contract work for Moog or
>something, and somehow the SSM chips eventually got used in some of their
>products. What I got was a clearly marked SSM 2020, but also an oddly
>marked IC with a Thomas parts number on it - 5099. I phoned and asked about
>this, and apparently this is supposed to be a 2040, only it has been
>screened with the Thomas parts number instead of the usual SSM2040. I don't
>really have a circuit to test these in (I'm not putting this in a
>synthesizer to test it thank you!),  so I was just wondering whether or not
>anyone else had found this site or tested one of these chips? Is it fairly
>normal for such chips to be re-screened by a manufacturer? 

Yes. I've seen a lot of ways that manufacturers will attempt to
disguise key parts (usually ICs) in a product. Rescreening is being nice - at
least you might have a chance at cross-reference. Other not so nice ways
include removing all ID marks and epoxy encapsulation. 

It's also fairly common practice for one IC to have several ID numbers,
depending on chip maker (usually a prefix/suffix change). They all work
identically. In fact,  the only numbering 'standard' for IC's is there *is* no
standard! It's not like caps or resistors. A chip maker can call it anything
they want. 

I'm certain the part you have (if cross-refed correctly) is a drop in
replacement. 

Irish



From irish at eskimo.com  Fri Jan  8 10:08:47 1999
From: irish at eskimo.com (Irish)
Date: Fri, 8 Jan 1999 01:08:47 -0800
Subject: gifs on diy
References: <v04003a00b2ba523fe895@[209.82.89.91]>
Message-ID: <9901080112370E.10364@Pandemonium>

On Thu, 07 Jan 1999, jc typed:
>
>Here's a proposition: we can try to get everyone on the synth-DIY and
>Analog lists to post their own and others' links to schematics archives and
>then we can collate the info into a "pseudo-standard" link pages that can
>be mirrored at anyone's page ... the info on this GIF-links page need only
>specify basic info of image files stored at the link pointed to ...

I have an abundance of available space on my host. It's not limitless, but I
could probably store a goodly number of drawings and B&W gifs. If we really
wind up with a huge lot, perhaps an appeal to Hyperreal for a 'area'. I'd
volunteer to maintain it. 

Irish



From Colin.Fraser at scottishpower.plc.uk  Fri Jan  8 10:22:01 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 8 Jan 1999 09:22:01 -0000 
Subject: AW: AW: VCO-1C #2
Message-ID: <BA865FF10473D211BC6F00805F0D830702D299@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Sean Costello [mailto:costello at seanet.com]
> Sent: 07 January 1999 17:25
> To: Haible Juergen
> Cc: DIY; Tony Allgood
> Subject: Re: AW: AW: VCO-1C #2
> 
> I thought that the CEM VCO's for the JP-6 and MKS-80 were selected for
> how well they would behave using Roland's hard sync.  Chips that would
> not sync properly would still be perfectly suited for the SH-101 and
> MC-202, where no syncing ability was necessary.

One of the worst things about the 3340 is the implementation of osc sync -
to do it properly you have to use external circuitry (as Roland did).
I made some comparisons between the oscillators on my Pro-One and my
Prodigy. There isn't really any audible difference between the unfiltered
waves by themselves but the difference between the depth of swept synced
oscillator effects is incredible, the Prodigy blows the P1 away - pity the
Prodigy doesn't have the same modulation section (yet !).

According to Roland - "The factory has had to selectively use the ..
CEM3340. This is because of characteristic variations among later CEM3340s
supplied from the manufacturer. And this makes VCO adjustments difficult
especially in SH-101."

The selection criteria are - "Can generate at very low frequency with low
CV." and "Can linearly track to VCO adjustment."
They put selected chips into two groups, both groups may turn up in the JP6
and MKS80, only the best turn up in the SH101.

Colin f



From zzynt at swipnet.se  Fri Jan  8 10:47:36 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 08 Jan 1999 01:47:36 -0800
Subject: AW: VC Phaser using the LM13600
References: <1BF5E20E0C4DD111BBAB00805FE2D58201151CD2@nbgm336a.nbgm.siemens.de> <199901071702.SAA17860@mail2.it.kth.se>
Message-ID: <3695D438.13E@swipnet.se>

Magnus Danielson wrote:

> As for lead/lag - you can't break the casuallilty without getting into
> trouble with Einstein. There have been some trouble regarding how low
> intensity (photon per photon) interferometers actually work with this
> respect and the best explanation comes from the transaction
> description of this interaction. Also, further trouble have been in
> the discussions of how fast a jump over a barriers (such as in a
> tunnel diod) actually takes, there are people discussing speeds in
> superluminar levels (that is, _faster_ than light). In Germany they
> had some fun and sent Mozart at 4.5 times the speed of light, without
> any noticable distorsion over a distance of 11 cm. Hope this is
> confusing ;)
> 
> Cheers,
> Magnus

Well , isn't that infact to get in trouble with Einstein?
Since he said, at the speed of light the time is still!!
Or iam lost in space?

BJ
(who practises Einsteins "relativ'ely" theory all the tima at the speed
of light in my bed!!) :)



From zzynt at swipnet.se  Fri Jan  8 10:52:52 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 08 Jan 1999 01:52:52 -0800
Subject: BJ's 4046 oscillator
References: <3695B73D.4C47@swipnet.se> <199901072336.AAA20900@mail2.it.kth.se>
Message-ID: <3695D574.929@swipnet.se>

> Magnus Danielson wrote:
>  >>
>  >> Hi!
>  >>
>  >> It just truck me that there is more to BJs 4046 oscillator.
>  >>
>  >> >From the two buffer op-amps comes two waveforms that look like this
>  >>
>  >> 0 V -   ---   ---   ---   ---
>  >> \  |  \  |  \  |  \  |
>  >> \ |   \ |   \ |   \ |
>  >> \|    \|    \|    \|
>  >>
>  >> 0V   ---   ---   ---   ---   -
>  >> |  \  |  \  |  \  |  \  |
>  >> |   \ |   \ |   \ |   \ |
>  >> \|    \|    \|    \|    \|
>  >>
>  >> Adding them creates a saw, but subtracting them and you got yourself a
>  >> triangle. Using the saw+square trick you can have a sawtooth of the
>  >> same frequency as the triangle, and they are in phase. A deglitching
>  >> is assumed ofcourse.
>  >>
>  >> Cheers,
>  >> Magnus
> 
>  B> Sorry, but the waves looks like this:
> 
>  B>           /|        /|        /
>  B>          / |       / |       /
>  B>         /  |      /  |      /
>  B> 0V-----/   |-----/   |-----/
> 
>  B>      /|        /|        /|
>  B>     / |       / |       / |
>  B>    /  |      /  |      /  |
>  B> 0V/   |-----/   |-----/   |-----

>  B> Therefore the final sawtoth wave is twice in
>  B> frequecy of the sqare wave available at pin 3 .
> 
>  B> A nother nice thing with this design is the ability to get PWM
>  B> by the usage of the Xor gate.It generates 100% PWM, no need for
>  B> external comparator.infact one can get PWM and Ring mod at the same time
>  B> from the same Xor gate.
> 
>  B> In wich way did you have in mind to do the saw to tri conversation?
>  B> Im not so sure that you relly get a nice and clean tri wave due to the
>  B> "out of phase" acting by each saw! If one would phase reverse one of the
>  B> waves then you might get a tri! I have to try to see!

BJ 
again



From rsowa at WizjaTV.pl  Fri Jan  8 11:03:33 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 11:03:33 +0100 
Subject: ODP: Digital DIY synths?
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6863@demon>

my 0.03 PLN
I can't say 16-bit A/D/As are expensive. I buy them for 4-10$, and they
sometimes are dual (or stereo if you like)

As for DAC-based envelope - in my Poly i use 7-bit control voltage, and
when I tweek, say VCF cutoff, the steps are not only noticable,
but anoying

Roman

> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	6 stycznia 1999 01:13
> Do:	Magnus Danielson
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: Digital DIY synths?
> 
> You could build a modular hybrid synth. For example, use an a/d -> cpu ->
> 
> d/a. I've been thinking about that. The cpu could be a cheapo, like the
> faster  
> 8051 parts or the Scenix ones. (They are more or less PIC compatible but
> run  
> at 50 MHz, all in a dip package.) The problem is that 16 bit a/d and d/a
> are  
> still expensive. Maybe one of the audio codec's (e.g. AD1847 as used in
> pc's)  
> would fit. Or, for fun, one could test the whole idea with 8 bit a/d and
> d/a.  
> Makes the software much easier too.
> 
> The problem with this whole idea is of course that cost go up pretty
> quickly  
> if you want a full modular this way. But I can imagine that a PIC with an
> 8  
> bit DAC would make a nice envelope generator.
> 
> Best regards,
> Ben



From zzynt at swipnet.se  Fri Jan  8 11:19:28 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 08 Jan 1999 02:19:28 -0800
Subject: Bobb de moog! delete if not piano!
References: <199901072358.SAA29205@smtp11.bellglobal.com>
Message-ID: <3695DBB0.332@swipnet.se>

Bob Moog have started to play piano again!

http://www.vankoevering.com/HTML/04about.htm

BJ



From irish at eskimo.com  Fri Jan  8 11:22:59 1999
From: irish at eskimo.com (Irish)
Date: Fri, 8 Jan 1999 02:22:59 -0800
Subject: Totally new to CV 
Message-ID: <99010802491200.13512@Pandemonium>

First, sorry for the cross-post, but I think it applies to both. 

While I am not a digital guru, I have a pretty good grip on how
DSP/sampler/MIDI stuff works. CV on the other hand is confusing me -
remarkable, because it's very simple. I get it; one volt per octave, OK. 
I am going to have at least one CV synth (a MadMouse, and I'm looking at that
quintisential Fatman) and I have been thinking about how I was going to control
it. I had this notion that a Midi/CV converter would allow me to use a Midi
keyboard/sequencer, but I really don't know how these work, and the pages I've
looked at so far seem to assume you do. Will it work the way I think it will?
Do I want it to? 
So I'm looking at Tom Gs pages more, and find this description on making a CV
controller by *chopping up a working keyboard!* Ahh! Now, it's not the doin'
that bugs me - I got the tools and the skill, it's the need. Do I need to do
this (have a CV controller)? Should I? He used a Miracle piano - I have one of
these, and will sacrifice it to the Analog Synth Cause if it's worth it (even
if I have discovered a drum section in it on channel 8 :) ) Also, while not
really much good for anything but a controller, it IS velocity sensitive; will I
lose that if I convert it? 

Thanks for cluing me in, 
Irish



From ben at stuyts.nl  Fri Jan  8 12:23:47 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri,  8 Jan 99 12:23:47 +0100
Subject: DSP Stuff
In-Reply-To: <9901080052130A.10364@Pandemonium>
References: <memo.19990107155654.262C@martink.compulink.co.uk>
	<9901080052130A.10364@Pandemonium>
Message-ID: <199901081123.MAA09754@daneel.stuyts.nl>

On Fri, 8 Jan 1999, Irish wrote:

> On Thu, 07 Jan 1999, Martin J Keefe typed:
>
> >The chip itself is definitely NOT a DIY item -- 100s of the tiniest surface 
> >mount legs I've seen, spaced very close together.
>
> If it's a kit, how are you supposed to mount the IC? Or does it come already
> soldered onto the board?

The name (EZKIT) is misleading. All those eval boards are fully assembled and  
tested. They want people to start _using_ the DSP, not burn it. B-) It's for  
learning about DSP's not about soldering SMD's...

Best regards,
Ben



From Juergen.Haible at nbgm.siemens.de  Fri Jan  8 12:28:14 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 8 Jan 1999 12:28:14 +0100 
Subject: AW: Phase and Delay (was: Phase vs. Delay)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820117EC86@nbgm336a.nbgm.siemens.de>


	>It's certainly true that a phase shift circuit makes a
	>fine vibrato.  But I'll claim that that this vibrato effect happens
	>because the phases of the component sines are changing and not
because
	>of any Doppler-like pitch shift due to storing the signal in a
medium
	>and pulling it out at a different rate.

I'd say it's not an either / or ; it's just a different view of the same
thing.
There is *something* stored in the capacitors (and inductors) of
a filter circuit. It's just that the waveform of the original is not
preserved, or in other words "the medium shows dispersion".

	>   At least *something* will show up in the output immediately. But
	>   the shape of your input will be altered, as different spectral
	>   components of your input signal will get different delay. That's
	>   how I think it works, at least.
	>
	>Well, let's see...  Imagine a single phase shift stage in front of
	>you, the classic opamp circuit.
	>
	>At low frequencies you'll have near 0 degrees phase shift, there's
no
	>delay because the signal goes straight through.
	>
	>At high frequencies there's 180 degrees phase shift.  Well not
exactly
	>phase shift; it's a straightforward polarity inversion.  No delay
	>there either.

What exactly does it mean when we speak of applying
one frequency f, and looking at phase and / or delay ?
It means that a sine wave of this frequency was switched
on in the infinite past. Otherwise we can't look at one single
frequency. Now we look at the input and output signal at
times >= 0. Asume we have a positive zero crossing at the input
at t = 0. The "same" zero crossing will appear at the output
after a certain time t1 > 0. Now we can refer to this time
directly (i.e. as delay), or in relation to the period of the sine
wave (i.e. as phase). Both descriptions are equivalent.

The problem is that you cannot know *which* zero crossing
is which, from just looking at input and output signal. The
zero crossing at the output at t1 might also be the result of
a zero crossing at the input an t = 0 - N * 1/f. So the delay
of the filter might be any N * 1/f + t1. You can measure 
phase (with its inherent ambiguity), but you cannot measure
the delay in this configuration. Not being able to measure it
doesn't mean it's not there, of course. And if you know a little
about the filter under test (number of poles etc.) you can 
decide which N is the right one, and thus decide on the 
right delay, too.

But accepted: That's not a typical experiment you would do
to measure a delay. And it's obvious why the *concept* of
frequency domain is generally described with amplitude
and phase rather than amplitude and delay.

But now let's look at time domain again. 

	>At low frequencies you'll have near 0 degrees phase shift, there's
no
      >delay because the signal goes straight through.

Let's make things easier and go to very low frequency, to
0Hz / DC.
We're switching on a DC source at the input at t=0.
(the same concept works for *any* frequency, but it's
easier to look at it for DC).
You're right: There is an (almost) immediate response on the 
output. But this is not a result of DC (or any other constant
low frequency applied) at all.
Switching the DC source on actually means a *step* that
contains all frequencies (and not just a single one). What
you see at the output immediately are the highest components
of the step's spectrum, and in fact this first part of the step
response is *inverted* (in the topology that has no inversion
for DC). After some time, the output signal crosses zero
and then approximates the DC input voltage.

Unfortunately, I cannot directly look at the step response
and see the group delay. (The step response is infinite,
but the delay on very low freq signals is finite ...) But one can
see a certain trend at least: There is an immediate
response with sharp corners <=> group delay approaches
zero for high frequencies. Output approaches input after
after some time <=> gain at low freq = 1, but there is some
delay ... things like that. I bet the system theory specialists
can read out much more, but not me ...

JH.




From ben at stuyts.nl  Fri Jan  8 12:31:32 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri,  8 Jan 99 12:31:32 +0100
Subject: DSP Stuff: computers with builtin DSP's
In-Reply-To: <002f01be3acd$222f8980$622e5380@s8p8t9>
References: <002f01be3acd$222f8980$622e5380@s8p8t9>
Message-ID: <199901081131.MAA09762@daneel.stuyts.nl>

On Fri, 8 Jan 1999, "Quint" wrote:

> Also if you on a quest with a budget don't forget that what started the
> craze was apples usage for programmable lucent dsp's in the 660, 880 av
> (audiovisual) series you can now pluck up from $150-$300, giving you a
> programmable dsp, realtime input & output (hard disk recording) of audio &
> video.
> They was also an early ppc version 601's but I think 6600,8800? which also
> are very cheap.  This is a great way to go if your just learning.

Actually, Steve Job's NeXT computers were there first. (1990?)

They have a Motorola 56002 on board, and it comes with development tools  
(assembler, graphical debugger). Also, they look much neater than Apple's.  
("He said, looking one right in the face.")

NeXT's are cheap too. Their main cpu is only a 68040 on 25 or 33 MHz, so they  
aren't the speediest ones. Although I still prefer them over wintel or mac  
boxes.

There's a very extensive MusicKit software for the NeXT somewhere at  
Stanford.edu. (I think it is at  
http://ccrma-www.stanford.edu/CCRMA/Software/MusicKit/MusicKit.html, but this  
might be outdated.) It also runs on pc's with NeXTSTEP a certain soundcards.

Best regards,
Ben



From ben at stuyts.nl  Fri Jan  8 12:35:07 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri,  8 Jan 99 12:35:07 +0100
Subject: gifs on diy
In-Reply-To: <99010800474508.10364@Pandemonium>
References: <1.5.4.32.19990107125058.006734d0@pop3.demon.co.uk>
	<99010800474508.10364@Pandemonium>
Message-ID: <199901081135.MAA09767@daneel.stuyts.nl>

On Fri, 8 Jan 1999, Irish wrote:

> On Thu, 07 Jan 1999, James Jackson typed:
> >>Now speed and bandwidth surely have improoved meanwhile,
> >>so it would make sense to loosen the rules a little.
> >>So I don't want this to be a "don't post pictures" post. But we
> >>should find a general rule about pictures, IMO. At least a size
> >>limit.
> >
> >How about a 5-10KB size limit?
> >
> It is possible to impose a size limit in some Mailing List software - on one
> of the dev lists I run I occasionally get "Hey, this 250k file I tried to
> post bounced!" and I always respond "Good." :)

Excellent idea! I've CC's the list maintainer, so maybe he can tell us if  
this is possible with the current list software.

Best regards,
Ben



From martink at cix.co.uk  Fri Jan  8 12:40:00 1999
From: martink at cix.co.uk (Martin J Keefe)
Date: Fri, 8 Jan 1999 11:40 +0000 (GMT)
Subject: DSP Stuff
In-Reply-To: <9901080052130A.10364@Pandemonium>
Message-ID: <memo.19990108114035.264A@martink.compulink.co.uk>


> Maybe not DIY for *you* :) but I'll bet not everyone has a Metcal 
> either (or a couple of years SMT rework experience). 

Hmm, I'd have a go at normal SMT stuff but these things have two 
connections per mm! That's 0.25mm pads with 0.25mm gaps between. And 
they're about 13mm on a side. Pretty demanding precision without 
specialist tools. Fabricating a PCB to those precisions and with 
multilayers would also be a challenge.

> If it's a kit, how are you supposed to mount the IC? Or does it come 
> already soldered onto the board?

It's a pre-built board with SHARC, stereo Codec, UART etc. Linked to PC 
via serial port.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From qfulsom at usa.net  Fri Jan  8 15:44:45 1999
From: qfulsom at usa.net (Quint)
Date: Fri, 8 Jan 1999 08:44:45 -0600
Subject: DSP Stuff
Message-ID: <000f01be3b15$6fc6bcc0$87fe5380@s8p8t9>

None of this is really meant to be soldered really, I dont see that you
could, if so its by wave.  The parts are too small and low in voltage to
traditionally solder.  That is why analog is so cool to work with for me.

-----Original Message-----
From: Ben Stuyts <ben at stuyts.nl>
To: <irish at eskimo.com>
Cc: DIY <synth-diy at mailhost.bpa.nl>
Date: Friday, January 08, 1999 7:19 AM
Subject: Re: DSP Stuff


>On Fri, 8 Jan 1999, Irish wrote:
>
>> On Thu, 07 Jan 1999, Martin J Keefe typed:
>>
>> >The chip itself is definitely NOT a DIY item -- 100s of the tiniest
surface
>> >mount legs I've seen, spaced very close together.
>>
>> If it's a kit, how are you supposed to mount the IC? Or does it come
already
>> soldered onto the board?
>
>The name (EZKIT) is misleading. All those eval boards are fully assembled
and
>tested. They want people to start _using_ the DSP, not burn it. B-) It's
for
>learning about DSP's not about soldering SMD's...
>
>Best regards,
>Ben




From rsowa at WizjaTV.pl  Fri Jan  8 15:51:33 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 15:51:33 +0100 
Subject: ODP: gifs on diy
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6866@demon>

Just an idea...

my website is yet under preparation, so I have few megs of space
to spare. Maybe I could provide it as a temporary URL for all pictures you
want to send to the list. Such a picture would sit there until
there wouldn't be place for new ones.
But I could be doing this with about half-day delay from receiving
picture to putting it on web.
Excluding weekends

Roman

> -----Oryginalna wiadomo??-----
> Od:	Haible Juergen [SMTP:Juergen.Haible at nbgm.siemens.de]
> Wys?ano:	7 stycznia 1999 13:09
> Do:	DIY
> Temat:	gifs on diy
> 
> Hi all,
> 
> I have seen several pictures posted to the entire list recently.
> This used to be unwanted in the past, because it costs bandwidth
> for *everyone* who is subscribed, not only the ones particularly 
> interested in the pictures.
> 
> JH.



From rsowa at WizjaTV.pl  Fri Jan  8 16:03:04 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 16:03:04 +0100 
Subject: ODP: Day Jobs
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6867@demon>

Aren't you too little to DIY young man? ;-)

It doesn't sound like 14-year-old boy
if I recall what I was doing at that age.
although i made my first circuit much earlier.

btw, my job is not in any way related to synths
or even electronics...
couldn't find good job :-(

Roman

> -----Oryginalna wiadomo??-----
> Od:	James Jackson [SMTP:james at newd.demon.co.uk]
> Wys?ano:	6 stycznia 1999 13:36
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Day Jobs
> 
> What are all of your 'Day Jobs'?
> 
> If you want to know about me.......
> 
> I am 14, and live in England. I have had a passion for electronics,
> computers and music for as long as I can remember. I put two and two
> together one day and realised that I could design amd make music
> electronic
> products. My interest in synths came about whilst using my schools's Juno
> 106. (Mmmm, lovely!). To feed my hobby, I design web-sites, and am
> currently
> working on a Synth / Musical Electronics page.
> 
> James Jackson.
> --------------------------------------------------------------------------
> -----
> James Jackson - New Era Web Designs
>           |
>           ------------------- james at newd.demon.co.uk
> Sales ------------------- sales at newd.demon.co.uk
> Information ------------ info at newd.demon.co.uk
> --------------------------------------------------------------------------
> -----



From chordman at flash.net  Fri Jan  8 15:52:32 1999
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 08 Jan 99 15:52:32
Subject: FatMan VCOs (Was Re: PAiA?)
Message-ID: <199901082353.RAA02759@echo.flash.net>

Guido Goebertus <guidogoe at xs4all.nl> wrote:
>Bill wrote:
>
>
>>The VCO outputs of the FatMan are sawtooth waveform. Not surprising, as the sawtooth is the easiest shape to generate with a r>
>
>>In the FatMan, the VCO input is a voltage-to-current conveter, the current charging the cap in the relaxation circuit. You can> 
> 
>>Bill Layer
>
>OK Bill, sounds very convincing, but I don't know, as I am not owning 
>a FATMAN yet, i merely planned to use it as the base of a modular setup.
Me too, when I can rub two minutes together... 

>I suggest you and Andrew perhaps discuss this further.
>Nevertheless, there was an article in a Dutch mag and they said it was 
>sawtooth, they truely did...
>
>Guido..

Stock, these are sawtooth only machines.  
However, the design invites addons.
IMHO that is _not_ a bad thing.


-- Scott Gravenhorst
-- RedWebMail by RedStarWare (srg)
-- FatMan Site: www.teklab.com/~chordman
-- Linux Rex, Linux Vobiscum





From Juergen.Haible at nbgm.siemens.de  Fri Jan  8 17:02:08 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 8 Jan 1999 17:02:08 +0100 
Subject: AW: AW: AW: VCO-1C #2
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820117EF48@nbgm336a.nbgm.siemens.de>

	>One of the worst things about the 3340 is the implementation of osc
sync -
	>to do it properly you have to use external circuitry (as Roland
did).
	>I made some comparisons between the oscillators on my Pro-One and
my
	>Prodigy. There isn't really any audible difference between the
unfiltered
	>waves by themselves but the difference between the depth of swept
synced
	>oscillator effects is incredible, the Prodigy blows the P1 away 

The 3340's *internal* hard sync is strange, no doubt.
(The Synton Syrinx uses this.)
But you're comparing the one-external-transistor method
(I asume the P1 has this one) with the Prodigy, aren't you ?

JH.



From rsowa at WizjaTV.pl  Fri Jan  8 17:09:08 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 17:09:08 +0100 
Subject: ODP: DSP Stuff
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6868@demon>

Hi Harvey and all
see my comments below:

> -----Oryginalna wiadomo??-----
> Od:	Harvey Devoe Thornburg [SMTP:harv23 at leland.Stanford.EDU]
> Wys?ano:	7 stycznia 1999 07:31
> Do:	mwmjr at ix.netcom.com
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: DSP Stuff
> 
> > 
> > >Beware, there are two EZ-Kit's: one with the ADSP2181, which is about
> $100.  
> > >This is a fixed point DSP. Then there's another one with the floating
> point  
> > >Sharc DSP, but it is more expensive. The floating point capabilities
> should  
> > >make it easier to program, but I have no experience with that.
> > >
	[Roman Sowa]  
	I have seen that one (SHARC that is) in action,
	and I almost bought it then. I costs about 300$.
	As for 2181 ezkit - well, it has software tools included and
manuals,
	but programs I develop on another platform

> Floating point is really the most natural for audio, because our 
> perception of frequencies and amplitudes is logarithmic, and also 
> because the most efficient attempts to simulate floating point
> with long ints in fixed point instructions almost always generates 
> unreadable code (reliance on shifts etc.) for ex. to divide by 255 
> (common in graphics and image processing) on a fixed point 
> machine it is easier use the 
> relation 1/255 = 1/256 + 1/256^2 + 1/256^3 + ... and use shifts and
> accumulates.  I have seen, but thankfully never had to write, this kind
> of stuff in audio applications.  Do you really want to be thinking 
> about this stuff (hint: the compiler never helps you) or thinking 
> about the algorithm?
	[Roman Sowa]  
	floating point is helpful when for example
	filter coefficients are more than 1 (and they like to be very much).
	In fix-pt you have to scale the coefs and signal, process it and
	rescale again. Besides SHARC's architecture is *much* easier
	to write especially in assembler. There are multi-purpose registers
	instead of ALU or MAC oriented. And there are more of them.
	more instructions and better cyclical addressing.
	I could go like this for hours...
	btw 2181 can divide. It takes 16 cycles, but can be done with
	2 instructions
>  
> One thing might be disturbing with floating point is the generation 
> of underflow errors. let's say you're using a one-pole filter for an 
> envelope generator (like for a 303 model) and there's a long time 
> between gates, then sooner or later you will underflow. 
> some processors (Pentium) react very poorly to this, causing much 
> slowdown (or maybe this is due to Microsoft DirectSound standard?) 
	[Roman Sowa]  
	That's why I cancelled subscribtion to music-dsp list. Everybody
	were Pentium-oriented, while most of the stuff made with real
	DSPs is simpler.
	In no way underflow will affect float-DSPs speed or funcionality.

> Traditionally the audio industry has used Motorola 56K's but many new
> companies are transitioning to ADSP21061 or 21160 (600 mflops) sharc.
> The main issue seems to be floating point, the availablity of
> C development environments, and parallelization (hardware support
> for multiprocessing stuff like semaphores). I think Digidesign still 
> uses 56K (which isn't much consolation for the $$$$$ for protools
> systems)!
> There is some effort underway to port Csound to the sharc but I am
> not up on this.
	[Roman Sowa]  
	SHARC is gaining because of $$$ droppings. When I first heard about
it
	it cost about 300-500$. Now I can buy it for 50$ in single
quantities.
	(10$ for OEMs)
	I no nothing about paralel processing, so this quad SHARC chip was
	for me only a cool looking device.

> Something which interests me is the TI stuff like TMS320C60 floating
> point series.  Performance is supposed to be in excess of 1000 mflops.
> But the evaluation kit costs $1500 not to mention 3rd party development
> tools.  I've been considering it (just to be different and to work
> with a more powerful machine) but I don't know many in industry who
> are adopting TI.
	[Roman Sowa]  
	I'd be interesting to see someone DIY with TMS320C6xxx.
	It's BGA package. Not to assemble with known to me tools IMHO.
	I was also considering buying this development system (fixed point)
	(I had an discount offer for just 1k$), but I'd rather spend it
	on Yamaha AN1x and tweek it ;-)
	TMS320C6xxx floating point so new that it's too hot for me.

	Roman
>  



From thudson at cygnus.com  Fri Jan  8 17:09:36 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Fri, 08 Jan 1999 11:09:36 -0500
Subject: ODP: Day Jobs
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6867@demon>
Message-ID: <36962DC0.7B335EE8@cygnus.com>

Roman Sowa wrote:
> 

> What are all of your 'Day Jobs'?
Software geek. But our office does have a soldering
station, so I can go and get a "fumes fix" when
the urge becomes too strong...

Thomas



From mark at spooky-solutions.co.uk  Fri Jan  8 17:10:39 1999
From: mark at spooky-solutions.co.uk (Mark Havard-Brown)
Date: Fri, 8 Jan 1999 16:10:39 -0000
Subject: gifs on diy
Message-ID: <00fe01be3b22$0606fa40$f48393c3@spookymb>

All,

I have access to some web space used by my company. It's not much, but I'd
be happy to publish any schematics received from Synth-DIY members. As for
downloading gifs, putting in a limit of 20K (whatever size) is fine, but
limits have a habit of being ignored or gradually growing until people start
to complain (again!).



Mark.






From Colin.Fraser at scottishpower.plc.uk  Fri Jan  8 17:13:56 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 8 Jan 1999 16:13:56 -0000 
Subject: AW: AW: VCO-1C #2
Message-ID: <BA865FF10473D211BC6F00805F0D830702D29C@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 08 January 1999 16:02
> To: Fraser, Colin J
> Cc: DIY
> Subject: AW: AW: AW: VCO-1C #2
> 
> The 3340's *internal* hard sync is strange, no doubt.
> (The Synton Syrinx uses this.)
> But you're comparing the one-external-transistor method
> (I asume the P1 has this one) with the Prodigy, aren't you ?

I don't know for sure - I don't have the schematics for the Pro-One. 
I looked over the circuit board briefly, and I couldn't see an external
transistor, so I assumed it was using the built in sync function.
Anyone with the schematic know for sure ?
The oscillators in my modular are also 3340s and their sync sound is pretty
much the same as the p1, with minor variations between the soft and hard
sync options, but no exciting sync noises to be had compared to the moog.

Is the sync on the Syrinx crap too ?

Colin f



From rsowa at WizjaTV.pl  Fri Jan  8 17:16:42 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 17:16:42 +0100 
Subject: ODP: DSP Stuff
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6869@demon>

I've read the manual of those experiments yesterday
(this is complete class-work tutorial)

This is great stuff for beginers, although some signal processing
background would help. Many simple programs.
Good start point to making nice DSP-based F/X

Roman

> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	7 stycznia 1999 01:29
> Do:	James Jackson
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: DSP Stuff
> 
> I recently found a web  
> site (http://www.ece.rutgers.edu/~orfanidi/ezkitl/ezkitl.html) with some  
> additional lab excercises for the EZKIT.
> 
> Best regards,
> Ben



From Juergen.Haible at nbgm.siemens.de  Fri Jan  8 17:38:56 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 8 Jan 1999 17:38:56 +0100 
Subject: AW: AW: AW: VCO-1C #2
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820117EF68@nbgm336a.nbgm.siemens.de>

	>I don't know for sure - I don't have the schematics for the
Pro-One. 
	>I looked over the circuit board briefly, and I couldn't see an
external
	>transistor, so I assumed it was using the built in sync function.
	>Anyone with the schematic know for sure ?

I don't have P1 schemos either, but I asume it's the same as
in the P5 (and the OB-Xa, OB-8, and even shown as an option
in the 3340 data sheet).

	>The oscillators in my modular are also 3340s and their sync sound
is pretty
	>much the same as the p1, with minor variations between the soft and
hard
	>sync options, but no exciting sync noises to be had compared to the
moog.

	>Is the sync on the Syrinx crap too ?

Speaking of crap in the Syrinx is sacrilegious - but yes, it *is* crap, IMO.
That is, if it's your synth's *only* hard sync. It's quite nice as an
option,
though - sonically somewhat between ordinary hard sync and soft sync.

A (crappy (:->) ) drawing with several 3340 sync types can be found at
http://www.synthfool.com/diy/hj2vco.gif
I have a 6-position switch that selects separate sync modes. You
can clearly see the external transistor for the P5 etc. style sync.
I have *never* really understood how it works - note that the transistor
is *not* connected to the VCO's capacitor, but to the buffered capacitor's
voltage. Somehow it discharges the cap thru the buffer (?).

I think this sounds *similar* to ordinary hard sync at least. But then
again I'm used to the sync sound of my OB-8 and Prophet 5 ...

Does anybody know what the Roland sync circuit (JP6 and MKS-80)
does ? The must have had some reason to use lots of transistors
instead of a single one. Is this an improovement over the P5
style sync, or did they just not know the one-transistor trick back
then ??

JH.





From Colin.Fraser at scottishpower.plc.uk  Fri Jan  8 18:20:42 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 8 Jan 1999 17:20:42 -0000 
Subject: 3340 sync
Message-ID: <BA865FF10473D211BC6F00805F0D830702D29D@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 08 January 1999 16:39
> To: Fraser, Colin J
> Cc: DIY
> Subject: AW: AW: AW: VCO-1C #2
> 
> 
> A (crappy (:->) ) drawing with several 3340 sync types can be found at
> http://www.synthfool.com/diy/hj2vco.gif
> I have a 6-position switch that selects separate sync modes. You
> can clearly see the external transistor for the P5 etc. style sync.
> I have *never* really understood how it works - note that the 
> transistor
> is *not* connected to the VCO's capacitor, but to the 
> buffered capacitor's
> voltage. Somehow it discharges the cap thru the buffer (?).
> 
> I think this sounds *similar* to ordinary hard sync at least. But then
> again I'm used to the sync sound of my OB-8 and Prophet 5 ...

I guess the 'buffer' in the 3340 is not really a buffer - otherwise it
shouldn't need another op-amp buffer on this output.
I used a voltage follower on this output - I haven't seen a summing node
used as in the schema above. Doesn't this load the cap ?

The E&MM Spectrum synth, which uses 3340s, uses an external FET which resets
the voltage on the timing cap directly.
See http://www.tellus.vallentuna.se/gymninfo/personal/anders/andersus.html
for the schematics.

I always meant to try this method out, maybe I will soon as I have a problem
with the octave position selector in a 3340 vco on the modular.

Colin f




From rsowa at WizjaTV.pl  Fri Jan  8 18:25:50 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 8 Jan 1999 18:25:50 +0100 
Subject: Vermona info needed
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D686B@demon>

Hi all,

Yesterday I buoght Vermona electronic percussion in pawn shop
for about 12$ :-O
totally not working, but after cleanning the fuse area it worked!
The sound is rather boring, as well as presets, but anyway it is
fine instrument. And vintage too! First in my future collection...

I was thinking about throwing up all those diode-memory and strange control
logic
and put uC in it.
But then it won't be so 'vintage' any more.

Does any of you good ppl have any info like schematics?
It is about 45x30x10cm box, 9 instrument volume knobs, master volume
with power switch, tempo knob, start/stop button, 15 preset buttons
(tango, samba, rock - this kind) + 1 shuffle, and two big (compared to LEDs)
flashing lamps.
No type name, just big VERMONA logo on control panel

Thanks

Roman



From cyborg0 at GlobalEyes.net  Fri Jan  8 18:27:42 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 08 Jan 1999 11:27:42 -0600
Subject: Day Jobs
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6867@demon>
Message-ID: <3696400E.EF5C19F5@globaleyes.net>

My day job used to be working for a dept. of defense contractor as an
instrumentation engineer.. I made LOADS of money, but the job was so
stifling,boring, and unpredictable (vacation, OH, you mean that
vacation, well we had something come up and...) I actually thought I was
going to go postal someday, so rather than kill my boss, I quit! :)) 

The title, instrumentation engineer, implied electronics, but in reality
it was nothing but 90% political BS and 10% electronics for 14+ hrs a
day. I guess I would have got along better if I would have drank lots of
beer, took prozac, didnt inhale, and cheated on my wife! <g> 

I think DOD contractors are the ONLY place that ppl with barely a high
school degree and NO experience can get the title of research
engineer(!?!?) and make 80k a yr. 

So, everybody, put on your poker face, takes LOTS of prozac (aka
breakfast to DOD contractor employees) and you too can have a money
filled unrewarding carreer with NO chance of promotion EVER! :)) (that
is, unless you get good photographs of the CEO with a hooker!)


Rob



From clark at andrews.edu  Fri Jan  8 18:43:50 1999
From: clark at andrews.edu (Tony Clark)
Date: Fri, 8 Jan 1999 12:43:50 -0500 (EST)
Subject: gifs on diy
In-Reply-To: <00fe01be3b22$0606fa40$f48393c3@spookymb>
Message-ID: <Pine.SOL.3.91.990108124150.15471D-100000@edmund.cs.andrews.edu>

> I have access to some web space used by my company. It's not much, but I'd
> be happy to publish any schematics received from Synth-DIY members. As for
> downloading gifs, putting in a limit of 20K (whatever size) is fine, but
> limits have a habit of being ignored or gradually growing until people start
> to complain (again!).

   Larger images can be sent to me personally for posting to the DIY Archive 
(as longs as they won't get me in trouble for posting them!).

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From Hcabnivek at aol.com  Fri Jan  8 18:48:23 1999
From: Hcabnivek at aol.com (Hcabnivek at aol.com)
Date: Fri, 8 Jan 1999 12:48:23 EST
Subject: SSM2040 (400 of them)
Message-ID: <b86a7a71.369644e7@aol.com>

Well it's official.  This organ repair co. has SSM2040's for $30. 
http://www.mitatechs.com/thomas.html
They confirmed that they had about 400 of them and that many of them were
marked "SSM2040", though others were marked with the Thomas organ part number
of 13-5009-6.  And I reminded them that their site listed is as a vco  but
that it actually was a vcf and they confirmed that  yes they were 2040's and
that yes they were vcf's.  If you ask nicely they will even make sure that the
ones they send you will actually say 2040 on them - until there gone.  Kind of
pricey, but I've gotta think this is the last big source out there.
I got mine, come and get 'em everyone!

Kevin



From guidogoe at xs4all.nl  Fri Jan  8 19:22:02 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 08 Jan 1999 18:22:02 GMT
Subject: gifs on diy
References: <9901080112370E.10364@Pandemonium>
Message-ID: <915816186-337008AEicMi@xs4all.nl>

Irish wrote:


>I have an abundance of available space on my host. It's not limitless, but I could probably store a goodly number of drawings and B&W gifs. If we really wind up with a huge lot, perhaps an appeal to Hyperreal for a 'area'. I'd volunteer to maintain it. 

>Irish

OK, you're in!

Guido




From b.layer at vikingelectronics.com  Fri Jan  8 19:47:19 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 08 Jan 1999 12:47:19 -0600
Subject: day job...
Message-ID: <3.0.6.32.19990108124719.007c1100@192.168.210.18>

Hey,

You've read the title, now hear the job:

"Sales Technician". Applications engineer, technical support, document
creation and development, general electro-mechanical engineering,
hand-holding, mule-skinning, meeting-attending, phone-talking jerk
blow-offing.

BTW, I'm actually a motorcycle mechanic by trade. Moto Guzzi, BMW, Triumph,
Ducati, Japanese etc.

 
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"



From vco at mindspring.com  Fri Jan  8 19:47:26 1999
From: vco at mindspring.com (tomg)
Date: Fri, 08 Jan 1999 13:47:26 -0500
Subject: Totally new to CV
In-Reply-To: <99010802491200.13512@Pandemonium>
Message-ID: <yam7677.1340.119073040@mail.mindspring.com>

On 08-Jan-99, Irish wrote:
>First, sorry for the cross-post, but I think it applies to both. 

>While I am not a digital guru, I have a pretty good grip on how
>DSP/sampler/MIDI stuff works. CV on the other hand is confusing me -
>remarkable, because it's very simple. I get it; one volt per octave, OK. 
>I am going to have at least one CV synth (a MadMouse, and I'm looking at that
>quintisential Fatman) and I have been thinking about how I was going to
>control
>it. I had this notion that a Midi/CV converter would allow me to use a Midi
>keyboard/sequencer, but I really don't know how these work, and the pages
I've
>looked at so far seem to assume you do. Will it work the way I think it will?

You press a key on your midi keyboard and the converter puts out
a gate and CV.
 
>Do I want it to?

Yes you do.
 
>So I'm looking at Tom Gs pages more, and find this description on making a CV
>controller by *chopping up a working keyboard!* Ahh! Now, it's not the doin'
>that bugs me - I got the tools and the skill, it's the need. Do I need to do
>this (have a CV controller)? 

No, any 1V/Oct source will work. Like PAiAs Midi2cv and a midi keyboard.

Should I? 

I really like having a CV controller. It's nice and simple being able 
to hook it up and go without having to crank up all the midi stuff. 

He used a Miracle piano - I have one of
>these, and will sacrifice it to the Analog Synth Cause if it's worth it (even
>if I have discovered a drum section in it on channel 8 :) ) Also, while not
>really much good for anything but a controller, it IS velocity sensitive;
will
>I
>lose that if I convert it? 

Yes. Coverting it changes everything. Much easier just to buy a
Midi2CV8 then use the Miracle as a midi controller. Although the 
Miracle does not have pitch bend or mod.

If you want a CV controller don't use your Miracle. Even though I
think it's pretty crappy, it does work as a midi controller. When
I built mine I did not have a good 1 switch per key curcuit. I do
now. A cheep Casio would be a lot easier to sacrifice. Find one
at the thrift store, cut it up and then use the 1 switch per key
converter at....

http://www.mindspring.com/~vco/misc/kbd_2d.html
 
If you use the Miracal anyway the sound module can be put in 
another case for use as a midi module. 

>Thanks for cluing me in, 
>Irish

Sure let me know if you have more questions.

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From vco at mindspring.com  Fri Jan  8 19:57:52 1999
From: vco at mindspring.com (tomg)
Date: Fri, 08 Jan 1999 13:57:52 -0500
Subject: Digital DIY synths?
In-Reply-To: <199901060004.BAA07994@daneel.stuyts.nl>
Message-ID: <yam7677.2622.119073040@mail.mindspring.com>

>I found the Yamaha An1x, which I could try out over the  
>holiday. (Yep, gonna keep it!) The whole DSP thing started to make more and  
>more sense to me. Not to mention being able to use it polyphonically.

Yeah! I spent a little time with this the other day. Pretty
good, the nord has a lot more edge but I like the sound of
the JP-8K best. If your going to buy a DSP machine check it 
out first.

I think it's interesting that all this DSP stuff sounds very
different depending on the name plate.

-tg










From qfulsom at usa.net  Fri Jan  8 20:11:31 1999
From: qfulsom at usa.net (Quint)
Date: Fri, 8 Jan 1999 13:11:31 -0600
Subject: Regarding DSP synths...
Message-ID: <002a01be3b3a$ede06280$44dd5380@s8p8t9>

speaking of could we maybe begin a list of dsp synths and what dsp is in
what synth?
I think that might be very helpful.
Quint


-----Original Message-----
From: Sean Costello <costello at seanet.com>
To: <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 3:11 PM
Subject: Regarding DSP synths...


>Hi all:
>
>This message just appeared on the Csound mailing list. If anyone is
>interested in developing a hardware DSP synth, using Analog Devices'
>XTCsound might be the way to go.  One warning: I've heard that the
>performace of the current XTCsound evaluation board isn't that hot (i.e.
>a 450 Mhz Pentium II running DirectCsound with no DSP board can
>outperform the XTCsound on the evaluation board). However, they are
>supposedly trying to iron out the bugs. Maybe the SHARC chips will be
>used someday to produce a Nord Modular type device, that can also be
>programmed in Csound, without the annoying hardware limitations of the
>Nord (i.e. the Nord can't do any type of synthesis, like granular
>synthesis, sampling, reverberation, etc. that requires delay memory).
>
>Sean Costello
>
>P.S.  I think that Scotty Vercoe is the son of Barry Vercoe, the MIT
>Media Lab professor who originally developed Csound.
>
>> Subject: RE: Linux Journal Csound article now on-line
>> Date: Thu, 7 Jan 1999 13:57:06 -0500
>> From: "Vercoe, Scotty" <Scotty.Vercoe at analog.com>
>> To: Richard Dobson <rwd at cableinet.co.uk>
>> CC: CSOUND <csound at maths.ex.ac.uk>
>>
>>
>> I'm not one to start rumors but...
>>
>> ADI has been making a multi-processor version of Extended Csound
(XTCsound) for
>> a customer.  It's fairly stable now, and our deadline is in a few months,
so it
>> should solidify soon.  I'm not sure when ADI will make these boards
available to
>> the public though.
>>
>> For anyone using our card, we'll soon have a 32-bit driver that crashes
much
>> less.  I'll post a message when it's on our site.
>>
>> Also, for a few of you who were interested in porting XTCsound to Linux
(Mac
>> anyone?), I will be getting a shipment of boards week after next (only 7
months
>> late!!).  Send me a note if you're still interested in a free card.
>>
>> thanks,
>> Scotty Vercoe
>> XTCsound Applications Consultant
>> Analog Devices Software & Systems Technology Division
>> Tel: (781) 461-3569       FAX: (781) 461-4291
>> Support: Csound.support at analog.com
>> Website: http://www.geocities.com/researchtriangle/thinktank/2138/




From dpattee at magi.com  Fri Jan  8 20:36:30 1999
From: dpattee at magi.com (David Pattee)
Date: Fri, 08 Jan 1999 19:36:30 +0000
Subject: day job...
References: <Pine.SOL.3.96.990108183718.8497D-100000@muss.cis.McMaster.CA>
Message-ID: <36965E36.FFC2248E@magi.com>

Graphic designer/Sound designer and composer for an interactive media company.
A dream job.

dave





From tom.verheyden at village.uunet.be  Fri Jan  8 20:45:33 1999
From: tom.verheyden at village.uunet.be (be053520)
Date: Fri, 8 Jan 1999 20:45:33 +0100
Subject: Day Jobs
Message-ID: <013b01be3b3f$74ff0100$3c9507c2@be053520>


-----Original Message-----
From: be053520 <tom.verheyden at village.uunet.be>
To: James Jackson <james at newd.demon.co.uk>
Date: woensdag 6 januari 1999 22:51
Subject: Re: Day Jobs


>
>
>>What are all of your 'Day Jobs'?
>
>
>Hi,
>I'm Tom Verheyden, I'm 22 years old and I live in Geel, Belgium.
>I work for Alcatel Bell telecom as a tester/troubleshooter
>(nothing really special, but now I'm aiming for a job @ Roland Benelux.
Hope
>it 'll work :-))
>My interest into synths came also from the Juno 106 (was about the first
>synth I've got (long time ago :-)).
>I combined music and electronics and made my first synth 4 years ago, now
>I'm mainly into modifying and repairing synths, drumcomputers and other...
>
>Bye
>
>Tom Verheyden
>
>
>
>




From aschrock at cs.brandeis.edu  Fri Jan  8 20:50:18 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Fri, 8 Jan 1999 14:50:18 -0500 (EST)
Subject: PAIA?
In-Reply-To: <915821778-455424AEicMi@xs4all.nl>
Message-ID: <Pine.SGI.3.95.990108144720.26686A-100000@opal.cs.brandeis.edu>

Nope! The fatman is a pulse (actually, really a square) wave only output.
Which is why it has a pretty inflexible sound unmodded... but you can mod
it with PWM and assumedly, waveshapers to add tri, saw, or whatever you
like. Just be careful, the power supply doesn't look too beefy, you might
want to put most of your mods on another PS. 

BTW, anybody know if the band 'not breathing' uses a fatman? I could swear
I hear it whining away on a track on their new double-cd album. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|

On Fri, 8 Jan 1999, Guido Goebertus wrote:

> Andrew wrote:
> 
> >You would definitely be interested in getting on the fatman mailing list.
> >I don't have the address offhand, but I'm sure if you search for it you'll find it. 
> 
> >The paia kit is IMO a good choice for modularization due to its price and the fact it's a kit. I have made a few fatmen semi-modular in the past,it's actually quite easy as long as you keep your wiring neat..
> 
> 
> O.K. , but do you know anything about the Fatman's VCO outputs?
> Is it a neat sawtooth output? (This is because I like to try the old multi-comparetor/LFO trick on it.)
> 
> Guido...
> 
> 




From guidogoe at xs4all.nl  Fri Jan  8 20:51:00 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 08 Jan 1999 19:51:00 GMT
Subject: PAIA?
References: <Pine.HPP.3.95.990106150502.5551A-100000@bay.cs.brandeis.edu>
Message-ID: <915821778-455424AEicMi@xs4all.nl>

Andrew wrote:

>You would definitely be interested in getting on the fatman mailing list.
>I don't have the address offhand, but I'm sure if you search for it you'll find it. 

>The paia kit is IMO a good choice for modularization due to its price and the fact it's a kit. I have made a few fatmen semi-modular in the past,it's actually quite easy as long as you keep your wiring neat..


O.K. , but do you know anything about the Fatman's VCO outputs?
Is it a neat sawtooth output? (This is because I like to try the old multi-comparetor/LFO trick on it.)

Guido...




From james at newd.demon.co.uk  Fri Jan  8 20:58:47 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Fri, 08 Jan 1999 19:58:47 +0000
Subject: Filters
Message-ID: <1.5.4.32.19990108195847.00674294@pop3.demon.co.uk>

Hi all,
        What are the reccomended cut-off ranges for a low pass filter. Would
0 to 20KHz be acceptable?

Thanks,
-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From theremin1 at worldnet.att.net  Fri Jan  8 21:12:07 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Fri, 8 Jan 1999 12:12:07 -0800
Subject: Digital DIY synths?
Message-ID: <003801be3b43$2b48ee00$14754e0c@hpcustomer>

I suppose we should REALLY bang two coconut shell halves together, if you
want to keep the Python motif!

-Art
-----Original Message-----
From: Florian Anwander <fa_diy at fa.camelot.de>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 7:56 AM
Subject: Re: Digital DIY synths?


>Hello Ben,
>
>>Switches? You had switches? Man, we had to bang two rocks together to get
any
>>sound and use lightning for special effects. And we were grateful for it.
>Did you read Magnus answer? We should bang not two rocks, we should bang
two
>symphonic orchestras...
>
>>I feel a Monty Python thread coming up...
>The first violinist will say: "ooh, it's only a scratch..."
>
>
>Gruss,
> Florian Anwander
>-------------------------------------------------------------------------
>Maus-Netz: Florian Anwander at M4
>Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
>## CrossPoint v3.11 R ##




From theremin1 at worldnet.att.net  Fri Jan  8 21:25:51 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Fri, 8 Jan 1999 12:25:51 -0800
Subject: Beginner's question
Message-ID: <004701be3b45$167c9c40$14754e0c@hpcustomer>

My 2 cents:

I am assuming, perhaps incorrectly, that your use of the term "etheral" is
in the conceptual, and not a brand-name, sense.  I'll take your meaning as
"ethereal," as in "other-worldly."

The pure sine wave is considered ethereal among thereminists.
This has some historic precedence in the work of Dr. Paul Tanner, who used
a sine wave laboratory oscillator to score everything from commercial
jingles
to the Beach Boys' "Good Vibrations."  Tanner's invention was akin to a
modern
ribbon controller, and its sound is often incorrectly attributed to a
theremin.
In fact, heterodyne 'mins do not make sines over the entire frequency range.
Tanners work was quite influential, and is invariably connected to many
ethereal arts genre.

-Art

-----Original Message-----
From: Claire F. <wils0450 at itlabs.umn.edu>
To: Synth-DIY <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 07, 1999 9:32 AM
Subject: Beginner's question


>Ok, I am trying to build a real "etheral" and "Pad-friendly" synth. I want
>to do it up kind of *like* the OB Matrix-100, but with frontpanel controls
>and twisty knobs. The only problem is, I don't know what (if it even
>matters) *kinds* of oscillators to use to produce an "etheral" effect.
>Can one kind of oscillator be that much better for one kind of sound than
>another? If so, would this same aspect apply to VCA, VCF etc. ?
>Thanks in advance!
>
>
> The Family Werks presents...
>                          Performing live at "Love"
> Valentine's day weekend in Minneapolis, MN USA
>             ****Sonic Boom of Love featuring Clarissa Fragile*****
>        (also Boo WIlliams and some other big-name chumps)
>
>




From magnus at analogue.org  Fri Jan  8 21:36:21 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 08 Jan 1999 21:36:21 +0100
Subject: AW: AW: AW: VCO-1C #2
In-Reply-To: Your message of "Fri, 8 Jan 1999 17:02:08 +0100 "
References: <1BF5E20E0C4DD111BBAB00805FE2D5820117EF48@nbgm336a.nbgm.siemens.de>
Message-ID: <199901082036.VAA10902@mail2.it.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 >> One of the worst things about the 3340 is the implementation of osc
 HJ> sync -
 >> to do it properly you have to use external circuitry (as Roland
 HJ> did).
 >> I made some comparisons between the oscillators on my Pro-One and
 HJ> my
 >> Prodigy. There isn't really any audible difference between the
 HJ> unfiltered
 >> waves by themselves but the difference between the depth of swept
 HJ> synced
 >> oscillator effects is incredible, the Prodigy blows the P1 away 

 HJ> The 3340's *internal* hard sync is strange, no doubt.
 HJ> (The Synton Syrinx uses this.)
 HJ> But you're comparing the one-external-transistor method
 HJ> (I asume the P1 has this one) with the Prodigy, aren't you ?

The EMM Spectrum synth (see Anders Sponton's webpage) uses external
cursuit to acheive 'propper' sync and also goes into describing how to
do it.

Cheers,
Magnus



From clark at andrews.edu  Fri Jan  8 21:40:19 1999
From: clark at andrews.edu (Tony Clark)
Date: Fri, 8 Jan 1999 15:40:19 -0500 (EST)
Subject: day job...
In-Reply-To: <3.0.6.32.19990108124719.007c1100@192.168.210.18>
Message-ID: <Pine.SOL.3.91.990108151024.5247A-100000@edmund.cs.andrews.edu>

   Okay, I'll byte:

   My official title is 'Production Manager' of A.U. Physics Enterprises, 
a small semi-independent company of Andrews University here in 
south-western Michigan.  I have been working here for about 7 years, 4 as 
a student worker and 3 as Production Manager after graduating from 
Andrews University with a BSET degree (engineering technology).
   A.U. Physics Enterprises manufactures teaching equipment specifically 
for the high school and college level.  Mostly Physics related.  Feel 
free to visit the company web page for a look at the products.  :)  It's 
quite possible that if you took college Physics, you've used a product of 
ours!
   Although my title is production manager, I also do all of the 
electronic design work, from PCB design to prototyping (the fun stuff!) and 
worker training.  Who likes bossing people around?  Give me a soldering 
iron and a schematic any 'ole day!
   I also teach a PCB design class for the Engineering Dept., utilizing 
OrCAD Capture and Layout.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From b.layer at vikingelectronics.com  Fri Jan  8 22:15:07 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 08 Jan 1999 15:15:07 -0600
Subject: PAIA?
In-Reply-To: <Pine.SGI.3.95.990108144720.26686A-100000@opal.cs.brandeis.
 edu>
References: <915821778-455424AEicMi@xs4all.nl>
Message-ID: <3.0.6.32.19990108151507.007cabd0@192.168.210.18>

Hi Andrew,

>Nope! The fatman is a pulse (actually, really a square) wave only output.
>Which is why it has a pretty inflexible sound unmodded...    

Oh-oh. I told out friend that it was a saw output... 

As I remember, the PAiA uses simple relaxation oscillators (not really
'oscillators' in the true sense). Relaxation circuits are inherely
sawtoothed...

As the circuit charges, you get your linear ascending ramp, when it
relaxes, you get a nearly vertical line... Isn't that a sawtooth?

Or is Billy boy a dumb bunny today?

BTW, I'm 29 years in age. I'll even go so far as to say that I'm 6'3" and
about 205lbs. My turn-ons include...






___      ___
\  \    /  /    E L E C T R O N I C S                Bill Layer
 \  \  /  / _   _  _   _   __  _   _____          Sales Technician
  \  \/  / | | | |/ / | | |  \| | /  _  \  <b.layer at vikingelectronics.com>
   \    /  | | |   \  | | |     | | (_) | 
    \__/   |_| |_|\_\ |_| |_|\__| \___  |     1531 Industrial Street
                                    __/ /     Hudson, WI. 54016 U.S.A
 http://www.vikingelectronics.com  /___/      715.386.8861 ext. 210




From aschrock at cs.brandeis.edu  Fri Jan  8 22:26:00 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Fri, 8 Jan 1999 16:26:00 -0500 (EST)
Subject: PAIA?
In-Reply-To: <3.0.6.32.19990108151507.007cabd0@192.168.210.18>
Message-ID: <Pine.SGI.3.95.990108162421.27038A-100000@opal.cs.brandeis.edu>

On Fri, 8 Jan 1999, Bill Layer wrote:

> Hi Andrew,
> 
> >Nope! The fatman is a pulse (actually, really a square) wave only output.
> >Which is why it has a pretty inflexible sound unmodded...    
> 
> Oh-oh. I told out friend that it was a saw output... 
> 
> As I remember, the PAiA uses simple relaxation oscillators (not really
> 'oscillators' in the true sense). Relaxation circuits are inherely
> sawtoothed...
> 
> As the circuit charges, you get your linear ascending ramp, when it
> relaxes, you get a nearly vertical line... Isn't that a sawtooth?

Yeah. Damn, I knew that. Uhm... sorry, my mistake. Haven't used the fatman
in a while.. I think I thought it was pulse since I saw a PWM mod for it
recently. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From james at newd.demon.co.uk  Fri Jan  8 22:37:21 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Fri, 08 Jan 1999 21:37:21 +0000
Subject: DSP Synth
Message-ID: <1.5.4.32.19990108213721.0066d57c@pop3.demon.co.uk>

Following on from the various DSP discussions flying around, I have finally
put up my prepositions for a DSP Based synth at the following address:

http://www.newd.demon.co.uk/dsp/index2.htm

As an added bonus, you get to see a picture of me!

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From vco at mindspring.com  Fri Jan  8 22:38:08 1999
From: vco at mindspring.com (tomg)
Date: Fri, 08 Jan 1999 16:38:08 -0500
Subject: Digital DIY synths?
In-Reply-To: <yam7677.2622.119073040@mail.mindspring.com>
Message-ID: <yam7677.412.118764312@mail.mindspring.com>

On 08-Jan-99, tomg wrote:
>>I found the Yamaha An1x, which I could try out over the  
>>holiday. (Yep, gonna keep it!) The whole DSP thing started to make more and 

>>more sense to me. Not to mention being able to use it polyphonically.

>Yeah! I spent a little time with this the other day. Pretty
>good, the nord has a lot more edge but I like the sound of
>the JP-8K best. If your going to buy a DSP machine check it 
>out first.

>I think it's interesting that all this DSP stuff sounds very
>different depending on the name plate.

I should also say the filter functions on most of this stuff
leaves me feeling unsatisfied! It's possible some sort of hybrid
would be really cool. 

Shamless Plug...

I'm just gona velco a Mad Mouse or two to the M1.(Sorry I tried 
but could not stop myself...:-)                 
                                     
-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From tsheets at saturn5.com  Fri Jan  8 22:50:16 1999
From: tsheets at saturn5.com (Troy Sheets)
Date: Fri, 8 Jan 1999 13:50:16 -0800 (PST)
Subject: day job...
In-Reply-To: <3.0.6.32.19990108124719.007c1100@192.168.210.18> from "Bill Layer" at Jan 8, 99 12:47:19 pm
Message-ID: <199901082150.NAA11076@atari.saturn5.com>


I'm troy, I am 26 and I am an electrical engineer in the Silicon Valley 
at Sun Microsystems...

I design boards for Sun's multiprocessor enterprise servers.

-troy

------------------------------------------------------------------------------
tsheets at saturn5.com                        <- You have found me   
http://www.saturn5.com/tsheets/audio       <- my .mp3 tracks
http://www.saturn5.com/tsheets/Casey3.wav  <- Casey Kasem in rare form



From guidogoe at xs4all.nl  Fri Jan  8 23:08:20 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 08 Jan 1999 22:08:20 GMT
Subject: PAIA?
References: <Pine.SGI.3.95.990108144720.26686A-100000@opal.cs.brandeis.edu>
Message-ID: <915829744-710402AEicMi@xs4all.nl>

My question:

> O.K. , but do you know anything about the Fatman's VCO outputs?
> Is it a neat sawtooth output? (This is because I like to try the old multi-comparetor/LFO trick on it.)
> 

Andrew wrote:

>Nope! The fatman is a pulse (actually, really a square) wave only output.
>Which is why it has a pretty inflexible sound unmodded... but you can mod it with PWM and assumedly, waveshapers to add tri, saw, or whatever you like. Just be careful, the power supply doesn't look too beefy, you mightwant to put most of your mods on another PS.

Oops... I'm glad you told me that.
I remember some 10 years ago (at least) I was trying to built an analog synth with various CPU timer circuits (6840 etc.) as a DCO connected to a Commodore 64 which was triggering a EG/VCF/VCA at the same time.
I also tried the C64's built in soundchip wich had an 8-bit tri/sq/sine/noise output, but they were very unreliable.
And it all sounded terrible squary.
Is there any alternative, (besides coocking transistors) or should I practise the fine art of waveshaping? :)

Thanx: Guido..




From eduni at ucsd.edu  Fri Jan  8 23:24:13 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Fri, 8 Jan 1999 14:24:13 -0800 (PST)
Subject: day job...
Message-ID: <199901082224.OAA15129@smtp.ucsd.edu>

-currently a sophomore at UCSD in EE (of course).  during breaks i intern at
Los Alamos National Laboratory (home of the atomic bomb), in the group
"LANSCE-9: High Power Microwave Sources and Effects, Advanced Accelerators
and Electrodynamics".  Basically lots of pulsed power (explosive and
traditional), high-power RF source development (reltrons, etc.) and so on.
I personally do most of my work on R&D of a "Spatially Modulated Non-linear
dielectric transmission line system", wherein we are trying to use
non-linear dielectrics to turn fast pulses into trains of high-frequency
solitons in an all solid-state system.  right now we mostly test prototype
solid-state high-power switches (Pulsed power Thyristors, MOS-Controlled
Thyristors, etc.) and hassle ceramics companies right now...  being the
student on the project, i actually spend most of my time hacking with messy
C code written by some guy at Oxford and reverse-engineering LabVIEW GPIB
drivers for archaic HP scopes that pre-date the GPIB protocol.. 

but the money is pretty good.. 

Ethan Duni




From dbalvage at ptdcs2.ra.intel.com  Fri Jan  8 23:24:49 1999
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Fri, 08 Jan 1999 14:24:49 -0800
Subject: day job...
Message-ID: <369685B1.167E@ptdcs2.intel.com>

Hello all -

I am Duane, I am 30, and I work for Intel Corp. as a chip layout

(mask) designer... I draw the innards of Pentium(r) II's by day,

and hack synthesizer guts by night. I have a BSAMT (automated 

manufacturing/robotics) from ITT Tech (don't laugh, it may not be

a big college, but I still make good money %^P ), and I have been toying

with electronics since I was a "wee lad"...And have wanted synths since

I first heard "Dream Weaver." ;^) 

BTW, it's very interesting to see the varied backgrounds we all come 

from. Kinda puts things in perspective.

				- Duane Balvage
-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From james at newd.demon.co.uk  Fri Jan  8 23:49:29 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Fri, 08 Jan 1999 22:49:29 +0000
Subject: EZ Kit Lite
Message-ID: <1.5.4.32.19990108224929.006c76ac@pop3.demon.co.uk>

Hi all,
        A question to anyone with an EZ Kit Lite (SHARC ADSP-21061 version)
Does the PCB allow the developer acces to all of the remainng data ports?

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From guidogoe at xs4all.nl  Fri Jan  8 23:50:58 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 08 Jan 1999 22:50:58 GMT
Subject: PAIA?
Message-ID: <915833718-505482AEicMi@xs4all.nl>

Discussion:
> 
> >The paia kit is IMO a good choice for modularization due to its price and the fact it's a kit. I have made a few fatmen semi-modular in the 
past,it's actually
> 
> O.K. , but do you know anything about the Fatman's VCO outputs?
> Is it a neat sawtooth output? (This is because I like to try the old multi-comparetor/LFO trick on it.)
> 
> Guido...

>Could you explain the "multi-comparetor/LFO trick" to me?

>thanks 

>Phillip

This is a bit hard to explain in words. I have the schematic, but as I'm writing this on 'obsolete' Atari 030 machine I will ask a PC friend to scan the image for me. I will post it when ready, but basicly it's a multi VCO simu.

OK?  Guido..
                           




From james at newd.demon.co.uk  Fri Jan  8 23:56:03 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Fri, 08 Jan 1999 22:56:03 +0000
Subject: Filters
Message-ID: <1.5.4.32.19990108225603.006c5f10@pop3.demon.co.uk>

>>What are the reccomended cut-off ranges for a low pass filter. Would
>>0 to 20KHz be acceptable?
>It would, if it was physically possible.
>No normal config will actually go to 'zero'.
>My filters are about 10Hz to 20K.

Ahh, I am designing my filters on a DSP chip, so it might be possible to
take it to zero. Thanks alot.

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From idreamin3d at toad.net  Sat Jan  9 00:06:09 1999
From: idreamin3d at toad.net (I Dream In 3D)
Date: Fri, 08 Jan 1999 18:06:09 -0500
Subject: day job...
In-Reply-To: <199901082150.NAA11076@atari.saturn5.com>
References: <3.0.6.32.19990108124719.007c1100@192.168.210.18>
Message-ID: <3.0.1.32.19990108180609.006b7220@toad.net>


I'm not supposed to talk about my job, but as long as I'm not too specific,
I guess I can tell all of you...

I work for the world's largest computer-based testing and education firm as
a Windows programmer.  I also get previews of tests from corp.'s such as
Microsoft, Novell, Sun, and other big guys.  And, I also have access to the
questions for just about every computer-based test from the A+ to MCSE.
Not as cool as it sounds...I am no longer eligible to take any of these
certifications which means my job is pretty much a dead end :-(

j at son
experimental musician
i break things on purpose




From guidogoe at xs4all.nl  Sat Jan  9 00:14:24 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 08 Jan 1999 23:14:24 GMT
Subject: PAIA?
References: <3.0.6.32.19990108144936.007cabd0@192.168.210.18>
Message-ID: <915833722-506266AEicMi@xs4all.nl>

Bill wrote:


>The VCO outputs of the FatMan are sawtooth waveform. Not surprising, as the sawtooth is the easiest shape to generate with a rudimentary VCO, which in most cases is a simple relaxation oscillator.

>In the FatMan, the VCO input is a voltage-to-current conveter, the current charging the cap in the relaxation circuit. You can see that increasing the current will speed the charging rate, and hence the frequency of the signal.
 
>Bill Layer

OK Bill, sounds very convincing, but I don't know, as I am not owning a FATMAN yet, i merely planned to use it as the base of a modular setup.
I suggest you and Andrew perhaps discuss this further.
Nevertheless, there was an article in a Dutch mag and they said it was sawtooth, they truely did...

Guido..




From limsf at muss.cis.McMaster.CA  Sat Jan  9 00:38:06 1999
From: limsf at muss.cis.McMaster.CA (Sen!)
Date: Fri, 8 Jan 1999 18:38:06 -0500 (EST)
Subject: day job...
In-Reply-To: <199901082150.NAA11076@atari.saturn5.com>
Message-ID: <Pine.SOL.3.96.990108183718.8497D-100000@muss.cis.McMaster.CA>

I'm an occupational therapist by day.

I specialize in augmentative communication and assistive technology.

Sen

     ____  ____  __/ /  l i m s f @ m u s s . c i s . m c m a s t e r . c a
    / _ / / _ / / _ /  s e n - f o o n g l i m b . s c b i o 9 4 & o t 9 9
   / __/ /___/ /___/  w e v e c o m e t o d e b a s e t h e c o i n a g e
  / /                t r i p h o p j u n g l e d u b d r u m ' n b a s s




From magnus at analogue.org  Sat Jan  9 03:01:26 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 09 Jan 1999 03:01:26 +0100
Subject: BJ's 4046 oscillator
In-Reply-To: Your message of "Sat, 09 Jan 1999 01:11:25 -0800"
References: <36971D3D.5A49@swipnet.se>
Message-ID: <199901090201.DAA13236@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> The new 4046 osc with PWM and ring mod at:(as usuall)
 B> http://home8.swipnet.se/~w-88660/schpcb.htm

 B> Besides that ,Magnus your triangle proposal will not work out!
 B> The reason! study the shape and the phase of the "half" saw wave
 B> and what happends when you try to invert it!! ;)

Argh! I forgot that the protection diod empties the cap... as allways
the devil is in the details, and the worst thing is that I knew it!!!

What you do get is a tri+square wave.

However, in the spirit of not giving up:
If you compare the one of the ramps to earth (actually, just above)
you get a close to perfect square that you can add the the soup and
kill out the square... but this is not really a neat solution.

 B> BJ
 B> (! nosaer eht staht,rehto chae fo esahp fo tuo ged 09 era sevaw eht)

 .mrofevaw eht no pu ti deweercs I tub ,esahp fo tuo ged 081 era yehT !epoN)
(!1+ ot 0 fo daetsni 1+ ot 1- norf seog pmar eht nehw sneppah tahw tuo kcehC

Cheers,
Magnus



From matthew at lith.com  Sat Jan  9 03:04:17 1999
From: matthew at lith.com (Matthew Allen)
Date: Fri, 8 Jan 1999 18:04:17 -0800 
Subject: day job...
Message-ID: <A4616F893E30D11199CD0000C0618AE56E27F8@mailserver.lith.com>

I'll one up ya. :-)

Lead artist video game company. Companies small enough that I have also done
sound design and music.

Fun
m.

		-----Original Message-----
		From:	David Pattee [mailto:dpattee at magi.com]
		Sent:	Friday, January 08, 1999 11:37 AM
		To:	synth-diy at mailhost.bpa.nl
		Subject:	Re: day job...

		Graphic designer/Sound designer and composer for an
interactive media company.
		A dream job.

		dave
		
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From 104065.2340 at compuserve.com  Sat Jan  9 03:10:26 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Fri, 8 Jan 1999 21:10:26 -0500
Subject: Day job...
Message-ID: <199901082110_MC2-6601-4799@compuserve.com>

Hi all:

For the last 15 years or so I have been running a laser lightshow business,
which had its beginnings in my synthesizer design work in the '70s.  Along
the way I've done a lot of analog and digital circuit design,
manufacturing, and outside consulting.  Recently I've grown tired of the
laser lightshow business, and I'm currently trying to sell it (any
takers?).

I now operate a new business in the cellular communications field.  I spend
a lot of time working with various wireless carriers, assisting RF
engineers in implementing their networks.  I still do circuit design here
and there,  more RF design, less analog and digital.  I also build and own
communications towers. 

Terry Michaels



From DJFonzi at pacbell.net  Sat Jan  9 04:28:22 1999
From: DJFonzi at pacbell.net (Cranium)
Date: Fri, 08 Jan 1999 19:28:22 -0800
Subject: Day job...
References: <199901082110_MC2-6601-4799@compuserve.com>
Message-ID: <3696CCD6.F0A29E75@pacbell.net>

    Just recently (by choice) unemployed.  Spent the last almost eight years
working in Bay Area (Ca.) music stores.  Worked quite a few at one of the
coolest used stores around.  Saw LOTS of neato vintage stuff there! (BTW, I'm
still on good terms, and know they have a boatload of service manuals, so if
you have specifics, let me know!)
    Just graduated from San Jose State, so now I'm outta work and school.
Trying to push my band IBOPA up the next rung, and have innumerable projects
laying around my garage.  Anybody know where I can buy an attention span?

                                                Mikel Z




From eboyz at obv-records.com  Sat Jan  9 04:34:58 1999
From: eboyz at obv-records.com (Steve)
Date: Fri, 08 Jan 1999 17:34:58 -1000
Subject: Day job...
References: <199901082110_MC2-6601-4799@compuserve.com>
Message-ID: <3696CE61.FE4ABB6F@obv-records.com>

My so-called 'real' job is a nuclear trained submarine electrician in the US
Navy.  I'm  a E-6.  I am currently a shore based instructor.  I also teach at a
local business college.  I am VERY eager to seperate from the military and
enter the real work force and get paid for what I do.

I have been to some pretty cool schools that help my synth DIY/modding habit.
I am a '2m' technician - meaning I have been to miniature and micro electronics
repair course.  Soldering from hell.  I learned to repair traces 3 layers down
on a damn flex-print, fix broken (as in 2 pieces) circuit boards,
non-destructive conformal coating removal and a host of other fun tasks that
are required to be done to specs that meet / exceed those of NASA.

Anyone need some assistance making their MOTM modules?? - They rock BTW if you
have not checked them out.

Steve (stuck in Hawaii because of said job)





From zzynt at swipnet.se  Sat Jan  9 04:54:02 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 08 Jan 1999 19:54:02 -0800
Subject: SSM2040 (400 of them)
References: <b86a7a71.369644e7@aol.com>
Message-ID: <3696D2DA.2BE4@swipnet.se>

Hcabnivek at aol.com wrote:
> 
> Well it's official.  This organ repair co. has SSM2040's for $30.
> http://www.mitatechs.com/thomas.html
> They confirmed that they had about 400 of them and that many of them were
> marked "SSM2040", though others were marked with the Thomas organ part number
> of 13-5009-6.  And I reminded them that their site listed is as a vco  but
> that it actually was a vcf and they confirmed that  yes they were 2040's and
> that yes they were vcf's.  If you ask nicely they will even make sure that the
> ones they send you will actually say 2040 on them - until there gone.  Kind of
> pricey, but I've gotta think this is the last big source out there.
> I got mine, come and get 'em everyone!
> 
> Kevin

Hip Hip horray!! Hip Hop horray!!

Klaus Shultze.



From vco at mindspring.com  Sat Jan  9 05:17:44 1999
From: vco at mindspring.com (tomg)
Date: Fri, 08 Jan 1999 23:17:44 -0500
Subject: UK MM orders?
In-Reply-To: <E0zynSk-0004rO-00.1999-01-09-01-45-14@mail2.svr.pol.co.uk>
Message-ID: <yam7677.2250.119395112@mail.mindspring.com>

Help! I got this from someone on the list and don't
know the answers? Names have been deleted.. private
mail and all...

I want to build a Mad Mouse..

>1. Are tha parts easy to find in the UK?

Can you guys from the UK order parts from US or is there
a better option? What about the rest of the world? I'm
getting a few international orders.

>2. How could I pay for the board from the UK?

There must be a way... I can't see getting involved with
credit cards to sell 40 pc boards.

>3. I dont have too much experience, How difficult is the synth 
>and how long will it take me to build?

If you don't have a CV controller (read old analog synth) add 
time to buy and build a paia midi2cv8. You must at least have a 
midi keyboard and a cv converter that sends pitch and gate.

I would say not too bad but the more experience the better
a good understanding of how a CV synth works is the most
important aspect. I would think about 4-6 hours assembly 
time. Others might have a different take on that. 

You have to punch and drill the case, stuff the board, 
mount the controls, fly the wires, mount the board and
scale the VCOs.

If it doesn't work it will take time to trouble-shoot and
fix the problem.

I'm still working on the assembly/setup guide and help page.

What do you think guys? It's a good time to find things like
this out. I can add it to the order/help pages.

-tg

BTW i'm getting requests for Maxx boards. I may do a two 
board set, use a 723 supply, heat up the VCOs, add the CA3280 
sine shaper to all 3 VCOs, throw in a full ms20 filter and the 
ultimate moog filter I've been working on and stuff it all into 
a 6 space rack. So if everything goes ok with the Mouse and it 
looks pretty good so far, maybe Maxx boards by April. I'm
thinking both boards for $75 bucks.

So if your thinking about the Maxx a Mad Mouse would be really
good practice..:-)

Or would you guys rather have something else?

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From budweiser at ozemail.com.au  Sat Jan  9 05:32:34 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Sat, 9 Jan 1999 15:02:34 +1030
Subject: day job...
Message-ID: <009101be3b89$154ed9c0$a0d26ccb@ppp.ozemail.com.au>


I'm a uni student pulling my way through Computer Systems Engineering.
Entering my 3rd year this year, ive just started an online business called
Funk Tech Systems (home of the 606 modbox, and Tom G's soon to be
released Maxx Modular). I also specialise in web design, some programming,
some unix stuff, and other things relating to
music/computers/electronics/consulting.

<bUd> / FTS




From honcho at paia.com  Sat Jan  9 06:00:49 1999
From: honcho at paia.com (honcho at paia.com)
Date: Fri, 8 Jan 1999 23:00:49 -0600 (CST)
Subject: FatMan VCOs (Was Re: PAiA?)
Message-ID: <199901090500.XAA18097@qns1.qns.net>



On Fri, 08 Jan 99, Scott Gravenhorst <chordman at flash.net> wrote:

>Stock, these are sawtooth only machines.  
>>>
Just so, and the power supply is beefy enough to handle another whole 
FatMan analog portion - exlusive of uC and PROM.

Another question that routinely comes up is: V/oct or V/Hz? It's V/Hz 
and the CV outputs on the panel are V/Hz also.

-John

---------------------------------------------------------
John Simonton                  PAiA Electronics, Inc
3200 Teakwood Ln.              honcho at paia.com
Edmond OK 73013                http://www.paia.com
405-340-6300                   fax 405-340-6378



From zzynt at swipnet.se  Sat Jan  9 06:10:11 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 08 Jan 1999 21:10:11 -0800
Subject: ODP: Day Jobs!! And deadly behaviour!
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6867@demon> <36962DC0.7B335EE8@cygnus.com>
Message-ID: <3696E4B3.4C7D@swipnet.se>

Thomas Hudson wrote:
> 
> Roman Sowa wrote:
> >
> 
> > What are all of your 'Day Jobs'?
> Software geek. But our office does have a soldering
> station, so I can go and get a "fumes fix" when
> the urge becomes too strong...
> 
> Thomas

Well, seriously speaking this is some thing you really should avoid
because most solder contaions led (Heavy Mettal)
This soldering smoke will instantly go upp your nose and plugg your
nose holes full with Heavy Metal!(guitar music).

When this happens your front part of your head gets extremly heavy and 
will fall forward with a "bang" into the PC keyboard where you 
(just at this moment) have finished your latest DSP synth software
for the Synth DIY list members.

When you crash your head into the PC keboard your 
nose(who is full of heavy metal)just happens too
poke the "del" buttom and all your nice software is gone.

What will this story tell you!

Well ,it will tell you that hevy metal is poisionus for the body
and your brain get "spoky" and you start to function badly!!!

Have a look at "Ozzy Osborne" and you will see why its 
dangerous to solder and to inhale the fumes!!

BJ
(who dont play the guitar but inhales the fresh swedish mountain air)



From jamos at technotoys.com  Sat Jan  9 06:45:39 1999
From: jamos at technotoys.com (Jim Johnson)
Date: Fri, 08 Jan 1999 21:45:39 -0800
Subject: day job...
In-Reply-To: <A4616F893E30D11199CD0000C0618AE56E27F8@mailserver.lith.com>
References: <A4616F893E30D11199CD0000C0618AE56E27F8@mailserver.lith.com>
Message-ID: <199901082145390840.00184411@smtp.transport.com>

OK, I'll bite - 

Software developer for Seer Systems, a software synth manufacturer. Someday
I'll get sick of synthesizers - maybe... :')






Jim Johnson
Seer Systems
jim at seersystems.com
(541) 431-0624




From dug at be.com  Sat Jan  9 07:59:23 1999
From: dug at be.com (Douglas Wright)
Date: Fri, 08 Jan 1999 22:59:23 PST
Subject: day job...
Message-ID: <199901090705.IAA03546@mailhost.bpa.nl>

I'm a software engineer at Be, Inc. working on audio drivers, the system audio mixer and our media kit.  BeOS is really coo, but I secretly wish I could play with analog gear all day.

dug
http://www.be.com



From jlarryh at iquest.net  Sat Jan  9 08:38:40 1999
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Sat, 9 Jan 1999 01:38:40 -0600
Subject: Steve's horrible day gig and MOTM
Message-ID: <199901090632.HAA29414@mailhost.bpa.nl>

----------
> From: Steve <eboyz at obv-records.com>
> 
> Anyone need some assistance making their MOTM modules?? - They rock BTW
if you
> have not checked them out.

Ditto.  I'm pretty excited about the ones shipping over the next few
months.
 
> Steve (stuck in Hawaii because of said job)

Steve, I am stuck in near zero weather in the Midwest with snow 1/2 way up
to my butt.  Please don't tell me you are "stuck" in Hawaii.  What a bummer
man.  NOT !!   <grin>

Larry Hendry






From aschrock at cs.brandeis.edu  Sat Jan  9 09:25:59 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 9 Jan 1999 03:25:59 -0500 (EST)
Subject: day job...
In-Reply-To: <Pine.SOL.3.91.990108151024.5247A-100000@edmund.cs.andrews.edu>
Message-ID: <Pine.SGI.3.95.990108163302.27038B-100000@opal.cs.brandeis.edu>

Day job? We students don't have a day job... Actually hell most of us need
one but I'm lucky.. 

As quick description, I'm a computer science / fine arts double
major (mostly painting/drawing) at Brandeis University who dabbles heavily
with synths and electronic music. Having so many hobbies is actually quite
a trick on no official income :) It's interesting to see how much of what
I learn crosses over from visual arts to music or vice-versa. (as has been
noted by others before in many different fields such as Edgar Froese,
David Lynch, and Autechre) 

Andrew
[ spreading himself too thin with too many interests... but therein lies
the fun.. or so I hope... ]

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From aschrock at cs.brandeis.edu  Sat Jan  9 09:54:14 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 9 Jan 1999 03:54:14 -0500 (EST)
Subject: UK MM orders?
In-Reply-To: <yam7677.2250.119395112@mail.mindspring.com>
Message-ID: <Pine.SGI.3.95.990109032026.19191A-100000@peridot.cs.brandeis.edu>

Mmm.. the maxx PCB would be a good idea. ASM-1 boards are still available
(i assume) but there's a gap to be filled in the DIY area between kits
such as MOTM or paia, which are reasonably idiot-proof, and 'total DIY',
where you fab or breadboard your own circuits. The intermediate range,
where you buy the PCB but locate your own parts/front panel is a little
empty at the moment. I know I certainly wouldn't be where I am now without
the ASM-1 and all the hell I went though trying to get that working. Just
last week I redid the entire wiring because it was pretty ferociously
noisy.. amazing how much you can learn in a year. 

As for sending money overseas, the absolute easiest way is via credit
card, since there's no overhead charges on your end. Other than that, if
you can't do a direct money transfer, your options are getting a global
money order or bank draft. I got one made up for Tony Allgood and it ran
me around 7$. A little steep, but certainly nothing too bad. Any bank will
do it for ya, altho you might get some raised eyebrows if you're only
getting it done for $25. 

IMO 4-6 hours is pretty conservative estimate for putting the mouse
together, especially if you're dealing with an intro-level project where 
lotsa newbies will be involved.. just a front panel could take you all
night if you're making it look purrty. 

Andrew
[ who just got his dual CEM3330 ringmod working... yeehaw.. CEM circuits
are lotsa fun to throw together... ] 

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|










From zzynt at swipnet.se  Sat Jan  9 10:11:25 1999
From: zzynt at swipnet.se (BJ)
Date: Sat, 09 Jan 1999 01:11:25 -0800
Subject: BJ's 4046 oscillator
References: <3695D574.929@swipnet.se> <199901080204.DAA00890@mail2.it.kth.se>
Message-ID: <36971D3D.5A49@swipnet.se>

> Well, in the normal saw-to-tri case you would extract such a spaced
> sawtooth that you then subtract with the saw (in a 1:2 mix) to get a
> triangle. Here you allready got the spaced saws, so it is only
> subtract these to each other.
> 
> Infact, the diff-voltage over the capacitor has a triangle shape, so
> setting up an op-amp as a diff-amp (using the existing buffer amps in
> BJs schematic) is a simple matter of a op-amp and a few resistors.
> 
> I even think that this might be a better solution than a normal
> saw-to-tri converter.
> 
> I will try it out, I have all the stuff around.
> 
> Cheers,
> Magnus

The new 4046 osc with PWM and ring mod at:(as usuall)
http://home8.swipnet.se/~w-88660/schpcb.htm

Besides that ,Magnus your triangle proposal will not work out!
The reason! study the shape and the phase of the "half" saw wave
and what happends when you try to invert it!! ;)

BJ
(! nosaer eht staht,rehto chae fo esahp fo tuo ged 09 era sevaw eht)



From brun at bart.nl  Sat Jan  9 11:51:12 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Sat, 9 Jan 1999 11:51:12 +0100
Subject: day job...
In-Reply-To: <3.0.6.32.19990108124719.007c1100@192.168.210.18>
Message-ID: <199901091052.LAA03104@Njord.bart.nl>

Well, my turn then.

I'm a copywriter  - daily writing loads and loads of texts about 
information and communication technology and financial stuff, like 
advertisements, brochures, mailings, web texts etc. Mostly in 
Dutch though. The company I work for is located in Hoofddorp, 
near Schiphol Amsterdam Airport. And oh: I like my job :-)

Jeroen




--> Brun, met een dakje op de u.

Nu ook op http://www.bart.nl/~brun/index.htm



From irish at eskimo.com  Sat Jan  9 13:11:27 1999
From: irish at eskimo.com (Irish)
Date: Sat, 9 Jan 1999 04:11:27 -0800
Subject: ODP: Day Jobs!! And deadly behaviour!
References: <3696E4B3.4C7D@swipnet.se>
Message-ID: <99010904132600.15936@Pandemonium>

On Fri, 08 Jan 1999, BJ typed:
>Thomas Hudson wrote:
>> 
>> Roman Sowa wrote:
>> > What are all of your 'Day Jobs'?
>> Software geek. But our office does have a soldering
>> station, so I can go and get a "fumes fix" when
>> the urge becomes too strong...
>> 
>Well, seriously speaking this is some thing you really should avoid
>because most solder contaions led (Heavy Mettal)
>This soldering smoke will instantly go upp your nose and plugg your
>nose holes full with Heavy Metal!(guitar music).
>
>When this happens your front part of your head gets extremly heavy and 
>will fall forward with a "bang" into the PC keyboard where you 
>(just at this moment) have finished your latest DSP synth software
>for the Synth DIY list members.

Would this be the source of the term 'head-banging' that is associated with
this kind of music? 

Irish



From jhaible at primus-online.de  Sat Jan  9 13:12:04 1999
From: jhaible at primus-online.de (jhaible)
Date: Sat, 9 Jan 1999 13:12:04 +0100
Subject: AW: day job
Message-ID: <19990110011756.22120.qmail@nuernberg2.pop.metronet.de>

I'm working for Siemens Automation & Drive.
We're still doing analogue things here, though most of it
is analogue behaviour of digital circuits, such as signal
integrity, EMC and hf decoupling of power supplies.
Working with Spice and with various electromagnetic field 
simulators.

JH.



From irish at eskimo.com  Sat Jan  9 13:14:01 1999
From: irish at eskimo.com (Irish)
Date: Sat, 9 Jan 1999 04:14:01 -0800
Subject: Day Job...
Message-ID: <99010904385002.15936@Pandemonium>

Um, OK. 
Until recently I worked on the assembly lines and in chop shops of a variety of
electronics manufacturers, including HP, Nintendo and Physio Control, for a
total of about 8 years. Eventually wound up as a Stores and Inventory director.
You name it, I've probably seen it and soldered it. 

Then I got a cool job... 

I now work in the Operations Center of the worlds largest NT datacenter. Come
and see it at MSN.com, Msnbc.com or Microsoft.com. I don't write code, me and
my team of ops keep the servers running. Which is not easy considering they
run NT... :) I'd tell ya more, but they won't let me :( 

Irish



From grbridgw at facstaff.wisc.edu  Sat Jan  9 13:20:40 1999
From: grbridgw at facstaff.wisc.edu (Gary R.Bridgwater)
Date: Sat, 09 Jan 1999 12:20:40 +0000
Subject: PLEASE remove
Message-ID: <3.0.2.32.19880101004313.007254c0@facstaff.wisc.edu>

Please remove grbridgw at facstaff.wisc.edu from your synth-diy email send
list. Thank you. 





From jhaible at primus-online.de  Sat Jan  9 13:31:55 1999
From: jhaible at primus-online.de (jhaible)
Date: Sat, 9 Jan 1999 13:31:55 +0100
Subject: AW: Re: Strange source for SSM2040 ICs?
Message-ID: <19990110011758.22120.qmail@nuernberg2.pop.metronet.de>

> Is $30 really that big a steal for a 2040? Or maybe just finding them is
a
> trick unto itself? Just curious, I got one in a box with some CEMs and
was
> wondering if it's worth that much. 

Well, you all know that I have repeatedly stated that the SSM2040 low pass
is 
my favorite filter ever.
Nevertheless, I think an SSM2040 is *not* worth 30 Dollars for a DIY
project.
I would surely spend 30 Dollars if Ihad a Rev. 2 Prophet with one defunct
VCF 
chip, because there is not much of an alternative. But for DIY ? That's
insane.
Build the replacment from hy homepage if you want that famous sound and
if you have enough PCB space. Don't get me wrong: I don't say the *price*
is 
insane - in fact I would not even sell one of my own 2040s for that price.
I just
say don't buy them for that price for new projects, even if there are 400
out there.
You neither do yourself a favor (at that price), nor does it any good to
Prophets
and Kobols that might desperatly need one at some time.

Just my opinion, of course. All I can offer is a free schematic of a
replacement
circuit (;->).

JH.





From irish at eskimo.com  Sat Jan  9 13:39:05 1999
From: irish at eskimo.com (Irish)
Date: Sat, 9 Jan 1999 04:39:05 -0800
Subject: Soldering from Hell. (was: Re: DSP Stuff) 
Message-ID: <99010905122804.15936@Pandemonium>

Sorry if this doesn't make the synth part of synth DIY... 

Martin Keefe wrote:
> Hmm, I'd have a go at normal SMT stuff but these things have two 
>connections per mm! That's 0.25mm pads with 0.25mm gaps between. And 
>they're about 13mm on a side. Pretty demanding precision without 
>specialist tools. Fabricating a PCB to those precisions and with 
>multilayers would also be a challenge. 

I ran a SMT machine that would place .25 parts at the rate of 60,000
parts per hour (standard sized chip resistors at upwards of 120,000 pph). Had
to rework by hand when the machine missed... 
PCB suppliers will usually go to that pad size (but not smaller) for about the
same price as thru-hole. Actually less for unmixed technology - no drilling! 

Quint wrote:
>None of this is really meant to be soldered really, I dont see that you 
>could, if so its by wave.  The parts are too small and low in voltage to 
>traditionally solder.

SMT parts are not usually soldered by wave, but by oven - a
solder paste is screened onto the board, and hold the parts in place when the 
machine places them. Then it gets baked :) But again, we did hand rework when
things went wrong. Had nice irons (and a heat gun), but really wasn't any
different than TH; you just had to be good! 

Then Steve wrote in another thread:
>I learned to repair traces 3 layers down  on a damn flex-print, fix broken
>(as in 2 pieces) circuit boards,  non-destructive conformal coating removal
>and a host of other fun tasks that  are required to be done to specs that meet
> / exceed those of NASA. 

Man, now *there's* stuff I wouldn't try to MilSpec! The multi-layer flex I
wouldn't even try, period. Although I have repaired unit that were in pieces
('run-overs') sucessfully, I doubt they would have passed any standard other
than 'smoke test' :) 

OK, I'll shut up now....

Irish



From uros.maver at ksop-cscp.si  Sat Jan  9 14:27:59 1999
From: uros.maver at ksop-cscp.si (uros maver)
Date: Sat, 9 Jan 1999 14:27:59 +0100
Subject: remove
Message-ID: <045401be3bd6$2dc86320$2f05f9c2@eniac>

remove
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/19990109/743489d7/attachment.htm>

From DCMagnuson at aol.com  Sat Jan  9 14:48:37 1999
From: DCMagnuson at aol.com (DCMagnuson at aol.com)
Date: Sat, 9 Jan 1999 08:48:37 EST
Subject: day job...
Message-ID: <fe675bd9.36975e35@aol.com>

I live in the tedious an not-too-stimulating world of heating, air
conditioning and refridgeration...  So if you need some extra cooling capacity
in your work shop for those long hot summer nights, you know who to call

I did start going to school for EE several years back, but had to drop out for
financial reasons.  I learned enough to understand how most circuits work, and
enough to get me tinkering.  

I also have a decent home recording studio that I hope to bump up into the
world of project studio, too.  A little recording on nights and weekends,
etc..

Dave Magnuson
Independent Music Site
http://members.aol.com/dcmagnuson 



From fa_diy at fa.camelot.de  Sat Jan  9 14:53:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 09 Jan 1999 15:53:00 +0200
Subject: day job...
In-Reply-To: <199901082224.OAA15129@smtp.ucsd.edu>
Message-ID: <78WpTHY$HFB@fa.camelot.de>

1983 - 1990 I did soundengineering in a recording studio in Munich, also did  
a lot of music, 1990 - 1996 I studied (politics and law) and while this  
earned money as writer for a german KEYS-magazine (similar to keyboards).  
Since 1997 I work as editor and layout-guy for a small magazine for public  
light rail systems (funnny thing), but at the moment I try to get back to  
music area also with my day job.


Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From peterc at pop.onwe.co.za  Sat Jan  9 15:02:05 1999
From: peterc at pop.onwe.co.za (peter_cornell)
Date: Sat, 9 Jan 1999 14:02:05 +0000
Subject: Day & night job....
Message-ID: <199901091154.NAA29623@mail-intertech.onwe.co.za>

Hi list

I do post audio for TV commercials on a Synclavier PostPro system. 
Could this fit into the Vintage Digital category?

Keep myself sane by building mic pre-amps (valve & discreet solid 
state) guitar amps & synth modules

Peter Cornell
Johannesburg



From varner at k-online.com  Sat Jan  9 15:53:25 1999
From: varner at k-online.com (Steve Varner)
Date: Sat, 09 Jan 1999 06:53:25 -0800
Subject: Beginner's question
References: <Pine.GSO.4.05.9901070844150.10770-100000@whale.itlabs.umn.edu>
Message-ID: <36976D64.1B856288@k-online.com>

Yeah, you need a sine wave generator in the VCO, or at least a good triangle
wave. You can try to filter more complex waveforms, but it's easier to start
with the simple waves. As was said, a ring modulator (balanced modulator)
will help give it a real spooky sound. These modulators are pretty simple to
make, a couple dollars worth of parts.

Claire F. wrote:

> Ok, I am trying to build a real "etheral" and "Pad-friendly" synth. I want
> to do it up kind of *like* the OB Matrix-100, but with frontpanel controls
> and twisty knobs. The only problem is, I don't know what (if it even
> matters) *kinds* of oscillators to use to produce an "etheral" effect.
> Can one kind of oscillator be that much better for one kind of sound than
> another? If so, would this same aspect apply to VCA, VCF etc. ?
> Thanks in advance!
>
>                          The Family Werks presents...
>                           Performing live at "Love"
>                 Valentine's day weekend in Minneapolis, MN USA
>              ****Sonic Boom of Love featuring Clarissa Fragile*****
>                (also Boo WIlliams and some other big-name chumps)






From budweiser at ozemail.com.au  Sat Jan  9 16:13:35 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Sun, 10 Jan 1999 01:43:35 +1030
Subject: Simple sample playback using EPROMs
Message-ID: <011201be3be2$a210a4c0$a0d26ccb@ppp.ozemail.com.au>

I was think about making a simple sample play back module that used
EPROMs, specifically for storing a 909 hihat and cymbol samples, complete
with the pitch control like the 909. I take it decay can be easily made
using
VCAs on the outputs together with an EG....

Does anyone have schematics on the web somewhere?
Obviously i'm going to need some sort of microcontroller,and i
assume this sort of technology has been used in all kinds of
machines over the years like the drumtracks, 707 909 etc..


<bUd>




From rsowa at WizjaTV.pl  Sat Jan  9 16:39:46 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Sat, 9 Jan 1999 16:39:46 +0100 
Subject: ODP: DSP Stuff: floating point or fixed point
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D686C@demon>


> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	8 stycznia 1999 00:38
> Do:	Michael Maloney
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: DSP Stuff: floating point or fixed point
> 
> I happened to read a couple of messages on comp.dsp about how a fixed
> point  
> DSP might be actually preferable over a floating point DSP. Here are some
> 
> quotes:
> ...
> > For operations such as FIR filtering, a fixed-point part has
> > GREATER precision (i.e., LESS noise) than a floating-point
> > device. This is because all fixed-point processors (that I've
> > ever seen, at least) that operate on N-bit data provide at
> > least a 2N-bit accumulator. For example, even a lowly 16-bit
> > fixed-point device such as the TI TMS320C50 has a 32-bit
> > accumulator. Thus one can carry forward 32 bits of precision
> > in the sum involved in the filter convolution, and if
> > noise-shaping is used, one can preserve much of that precision
> > when converting back to 16-bit values.
	[Roman Sowa]  
	Say, what?...
	Not satisfied with IEEE floating point format? Why not use
	40-bit floats in SHARC. And you can also use it as 32-bit
	fixed poit DSP

	Roman
>  
> 



From jdec at mindspring.com  Sat Jan  9 17:37:50 1999
From: jdec at mindspring.com (Bright Boy)
Date: Sat, 9 Jan 1999 11:37:50 -0500 (EST)
Subject: Simple sample playback using EPROMs
Message-ID: <199901091637.LAA28823@camel7.mindspring.com>

>Does anyone have schematics on the web somewhere?
>Obviously i'm going to need some sort of microcontroller,and i
>assume this sort of technology has been used in all kinds of
>machines over the years like the drumtracks, 707 909 etc..

There was an issue of Electronic Musician back in the late
80's that featured such an article.  The project is probably
simpler than you think because it didn't use a microcontroller
at all.  You basically just need to reset and fire off a counter
that drives the address lines on the EPROM every time you
trigge the module.  Of course you'll also need a D/A converter
connected to the data lines of the EPROM to reconstruct the
audio....

If I can find the issue I'll let you know.  I could possibly scan
the schematic at work and email it to you....

Cheers,

Jeff R. Dec




From blayer at uswest.net  Sat Jan  9 17:45:03 1999
From: blayer at uswest.net (Bill Layer)
Date: Sat, 09 Jan 1999 10:45:03 -0600
Subject: My site is up...
Message-ID: <3.0.6.32.19990109104503.007b31d0@192.168.0.1>

Hey all,

Finally!

Check out <http://www.condor-connection.org/blayer>

There is an issue with the graphics loading slowly, we are working on it.


+----------------------------------------------------------+
|      "The" Bill Layer - Frogtown, Minnesota. U.S.A.      |
| Vacuum tubes, Analog, Motorcycles and Other Alternatives |
+----------------------------------------------------------+	
+---------------------+  +---------------------------------+
| <blayer at uswest.net> |  | <b.layer at vikingelectronics.com> |
+---------------------+  +---------------------------------+




From Ullrich at kapsch.net  Sat Jan  9 17:48:40 1999
From: Ullrich at kapsch.net (Ullrich at kapsch.net)
Date: Sat, 9 Jan 1999 17:48:40 +0100
Subject: day job
Message-ID: <13673333E22DD211B57F0000F8CB39FFABAF23@tick.kapsch.co.at>

I am working as a "hardware and software development enginner" in the medium sized Austrian company KAPSCH. I am currently working on a European railway radio system based on GSM-R.

Prozessors: 8051, 80C166 (hardware), ADSP2181 (a little bit of software - analog synth emulator)

	Ciao
	Peter

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/                                                                  




From ben at stuyts.nl  Sat Jan  9 18:04:03 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sat,  9 Jan 99 18:04:03 +0100
Subject: Filters
In-Reply-To: <1.5.4.32.19990108225603.006c5f10@pop3.demon.co.uk>
References: <1.5.4.32.19990108225603.006c5f10@pop3.demon.co.uk>
Message-ID: <199901091704.SAA10577@daneel.stuyts.nl>

On Fri, 08 Jan 1999, James Jackson wrote:

> Ahh, I am designing my filters on a DSP chip, so it might be possible to
> take it to zero. Thanks alot.

That is interesting. What kind of filter are you designing? I'm interested in  
the topology, and what kind of effect it has. Will it have the usual cut-off  
and resonance controls?

Are you trying to get something similar to an existing analog filter?

Best regards,
Ben



From edusilva at bahianet.com.br  Sat Jan  9 18:40:36 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 9 Jan 1999 15:40:36 -0200
Subject: day job...
Message-ID: <199901091743.PAA03626@postman.bahianet.com.br>

I work for ES2 Audio, a small P.A. rental company. In fact, so small that
I'm the owner and the only full-time employee...

Not a "synthish" job, but real DIY - more than 50% of the audio gear I use
was designed and built all by myself. Lightning, cables, racks, direct
boxes, instrument monitors and a processed system: speakers with lots of
electronics (amps, eq, crossover, limiters, etc) stuffed in. Believe it or
not, it works! (well, not always... :( )

BTW, if you want to know more about the P.A. systems we have here in my
city, follow the link below

http://galileo.mpc.com.br/users/p/paulo.albuquerque/trio/trio.htm

Ax?!
Edu

_____________________
Edu Silva - ES2 Audio
Salvador-Bahia-Brasil



From martin at manikin.force9.co.uk  Sat Jan  9 19:54:58 1999
From: martin at manikin.force9.co.uk (Martin Fay)
Date: Sat, 09 Jan 1999 18:54:58 GMT
Subject: UK MM orders?
In-Reply-To: <Pine.SGI.3.95.990109032026.19191A-100000@peridot.cs.brandeis.edu>
References: <Pine.SGI.3.95.990109032026.19191A-100000@peridot.cs.brandeis.edu>
Message-ID: <36994cc4.1565695@relay.force9.net>

Andrew wrote:
>As for sending money overseas, the absolute easiest way is via credit
>card, since there's no overhead charges on your end. Other than that, if
>you can't do a direct money transfer, your options are getting a global
>money order or bank draft. I got one made up for Tony Allgood and it ran
>me around 7$. A little steep, but certainly nothing too bad. Any bank will
>do it for ya, altho you might get some raised eyebrows if you're only
>getting it done for $25. 

It might be an option to arrange a bulk order if someone has the
time/inclination to arrange it?

While I'm posting I might as well join in the jobs thing:

Job #1 is just turning into a project to implement a distributed
search system to integrate both public/proprietry information/contacts
on corrosion.

Job #2 is creating software synths (VAZ+, VAZ Modular)...

On the diy front I intend to add some kind of support for very
lightweight "prototype" modules to be added to VazMod, a full plugin
system would almost certainly be too difficult to work with to be
worthwhile. The approach I intend to use would be more like a dll with
a single exported function.



Martin




From james at newd.demon.co.uk  Sat Jan  9 20:06:53 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Sat, 09 Jan 1999 19:06:53 +0000
Subject: Filters
Message-ID: <1.5.4.32.19990109190653.0067a53c@pop3.demon.co.uk>

>> Ahh, I am designing my filters on a DSP chip, so it might be possible to
>> take it to zero. Thanks alot.
>Are you trying to get something similar to an existing analog filter?

Yes, I am designing a Physical Modelling synth. See:

http://www.newd.demon.co.uk/dsp/

for details of it so far.

>What kind of filter are you designing?

There will be three types available to the user: High - Pass, Low - Pass and
notch Pass.

>I'm interested in the topology, and what kind of effect it has.
>>Will it have the usual cut-off and resonance controls?

The filters will be based around Fourier Transform algorithms, so I'll have
to teach myself how to do Fourier Transforms! Yes, they  have the usual
'Analog Style' controls, as I want to make my synth as Analog as possible.

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From magnus at analogue.org  Sat Jan  9 20:15:49 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 09 Jan 1999 20:15:49 +0100
Subject: Filters
In-Reply-To: Your message of "Sat,  9 Jan 99 18:04:03 +0100"
References: <199901091704.SAA10577@daneel.stuyts.nl>
Message-ID: <199901091915.UAA18058@mail2.it.kth.se>

>>>>> "BS" == Ben Stuyts <ben at stuyts.nl> writes:

 BS> On Fri, 08 Jan 1999, James Jackson wrote:
 >> Ahh, I am designing my filters on a DSP chip, so it might be possible to
 >> take it to zero. Thanks alot.

 BS> That is interesting. What kind of filter are you designing? I'm interested in  
 BS> the topology, and what kind of effect it has. Will it have the usual cut-off  
 BS> and resonance controls?

 BS> Are you trying to get something similar to an existing analog filter?

The benefit with digital IIR filters is that 0 Hz is as achievable as
1 kHz. An integrator for instance can be perfect as long as it does
not saturate (it will wrap). An analog filter will would suffer the
leakage of the capacitor and surrounding curcuit to be anyway near 0
Hz, but it may get efficiently near 0 Hz seen from a audio
perspective.

These filters are fairly simple to acheive, a few multiplies and a few
additions. The calculations are a bit worse, but they are managable.

Cheers,
Magnus



From james at newd.demon.co.uk  Sat Jan  9 20:26:45 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Sat, 09 Jan 1999 19:26:45 +0000
Subject: Web Site
Message-ID: <1.5.4.32.19990109192645.00684944@pop3.demon.co.uk>

Hi All,
        I've had an idea... Would you all think it would bea good idea to
have a list web site, with a bit of information on the list, and where list
members can have a little about themselves on it (See Day Job Items), and
maybe even a photo. I would be happy to look after and host this, as I have
about 10MBs spare on my server.

We could also have information about projects people are working on on it.

Any comments?

If anybody wants to send me photos / information, then please E-Mail me
privately (james at newd.demon.co.uk) and I'll design a site and get it up and
running.

-JJ
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From per.mattsson at mkv.mh.se  Sat Jan  9 20:46:18 1999
From: per.mattsson at mkv.mh.se (Per Mattsson)
Date: Sat, 09 Jan 1999 20:46:18 +0100
Subject: Day job...
Message-ID: <fc.000f49240038190a000f49240038190a.381924@mkv.mh.se>

My job is divided between lecturing "normal" 2D and 3D graphics and design
at a Swedish university and beeing the sysadmin of our faculty. The days
are filled with Photoshop, Quark Xpress, TCP/IP, hung servers etc. 
Before this I worked as a photographer and graphics artist at a
tevestation.  I still do alot of CD-covers, posters etc, hint-hint :)

---Per Mattsson




From cyborg0 at GlobalEyes.net  Sat Jan  9 21:00:06 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sat, 09 Jan 1999 14:00:06 -0600
Subject: touch interfaces, tact buttons, covers, interfaces, etc..
Message-ID: <3697B546.A85323BD@globaleyes.net>

WEll, I have a LOT of questions about interfaces..
Ok, has anyone had any real-world experience with touch panels? How
reliable are they? I kind of like these because they incorporate
debounce within the touch circuit and they take up very little space. I
also think that these could be made to work with resistive ribbon like
having little ribbon controller squares with zones marked on it for the
various functions instead of buttons.
downside is they have no touchy feeliness to them and they would be
labor intensive.

Next, is the good ol tact switches.. Now, I can find a regular banquet
of these little things which would do the trick, but the downside is
that I cannot find decent tact switch button covers. I have found some,
but they need buttons that are too high for my application. Anybody know
where the heck to get buttons that will just "sit" over the tact
switches? It is pretty much that I will have to go to a plastics
manufacturer to get polystyrene button "trees" made? 

At first glance, I wouldnt mind doing this, but then that means I have
to get on autocad and design a 3d prototype and then have the mold made
(now this is expensive!) but after that, the per button cost would be
extremely cheap, like .001 dollars per tree. The startup would really
kill me though..

I have actually thought about going to a local machine shop and having a
guy make me just 6mm squares of brushed aluminum stock with little nubs
underneath just big enough to keep the buttons from slipping through the
button holes when you turn the machine upside down.
The drawback to this is I will prlly pay about $1 a piece for these
nifty brushed aluminum button caps, and per unit there are about 25. 
The machinist said it would take him about 20 minutes to make a set of
em, and the only reason it takes that long is that he has to pull out
milling bits he usually doesnt use! :)
This seems like by FAR the coolest way to do it, but if someone knows of
a place that can do it for cheaper, let me know!

Any and ALL opinions appreciated.

My god, I NEVER knew how intensive panel layout could BE! Esp. when you
are modding already existing interfaces.. I would have prolly been
easier for me to design an entirely new product from the ground up.. but
I still like this a lot better than reading off projectile velocities
from a radar screen all day.. :))

Rob



From magnus at analogue.org  Sat Jan  9 21:16:38 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 09 Jan 1999 21:16:38 +0100
Subject: Web Site
In-Reply-To: Your message of "Sat, 09 Jan 1999 19:26:45 +0000"
References: <1.5.4.32.19990109192645.00684944@pop3.demon.co.uk>
Message-ID: <199901092016.VAA18412@mail2.it.kth.se>

>>>>> "JJ" == James Jackson <james at newd.demon.co.uk> writes:

 JJ> Hi All,
 JJ>         I've had an idea... Would you all think it would bea good idea to
 JJ> have a list web site, with a bit of information on the list, and where list
 JJ> members can have a little about themselves on it (See Day Job Items), and
 JJ> maybe even a photo. I would be happy to look after and host this, as I have
 JJ> about 10MBs spare on my server.

Well, there is one... at:

http://zoutmijn.bpa.nl/Rick.Jansen/Emusic/Synth-diy/synth-diy.html

also, in the Analogue Synth FAQ you find a reference:

http://pages.pomona.edu/~jmaxwell/faq.html

But, that doesn't really say that your idea is particullarly bad one.
I would say that the list's website is just distributed but with a bit
unorganized central reference. Fixing that is easy, fixing all the
info is a much troughter job.

Like others I try to collect relevant information under
http://www.it.kth.se/~e93_mda/synths/

Cheers,
Magnus



From aschrock at cs.brandeis.edu  Sat Jan  9 21:21:56 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 9 Jan 1999 15:21:56 -0500 (EST)
Subject: Web Site
In-Reply-To: <1.5.4.32.19990109192645.00684944@pop3.demon.co.uk>
Message-ID: <Pine.SGI.3.95.990109151503.20421A-100000@peridot.cs.brandeis.edu>

I suggested something similar a while ago (a page with list members music)
and it got put down enough so that I lost enthusiasm for it. I still think
it's a good idea, but many thought it was rather off-topic for the list..
but in light of all the off-topic posts, a web page with this sort of info
might prove to have a de-cluttering effect. I'd be happy to help out if
you need it. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|

On Sat, 9 Jan 1999, James Jackson wrote:

> Hi All,
>         I've had an idea... Would you all think it would bea good idea to
> have a list web site, with a bit of information on the list, and where list
> members can have a little about themselves on it (See Day Job Items), and
> maybe even a photo. I would be happy to look after and host this, as I have
> about 10MBs spare on my server.
> 
> We could also have information about projects people are working on on it.
> 
> Any comments?
> 
> If anybody wants to send me photos / information, then please E-Mail me
> privately (james at newd.demon.co.uk) and I'll design a site and get it up and
> running.




From theremin1 at worldnet.att.net  Sat Jan  9 21:44:12 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Sat, 9 Jan 1999 12:44:12 -0800
Subject: Soldering from Hell. (was: Re: DSP Stuff) 
Message-ID: <007901be3c10$d11af260$ce794e0c@hpcustomer>

Irish wrote:

>OK, I'll shut up now....

I write:

No! Don't hold back!  It is really nice to have some 
production folks like you on this list.  Gives a whole 
lotta insight regarding the practical aspects of 
electronics manufacturing, and that could never be 
a bad thing.

Art Harrison,
Once a TH machine technician








From edusilva at bahianet.com.br  Sat Jan  9 22:13:49 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 9 Jan 1999 19:13:49 -0200
Subject: SH09 service manual
Message-ID: <199901092115.TAA15180@postman.bahianet.com.br>

My little SH09 (Roland) needs its service manual, or at least, a
schematic. Can any of you guys help this unhappy synth?

Edu


_____________________
Edu Silva - ES2 Audio
Salvador-Bahia-Brasil



From halfmast at clubmet.metrobbs.com  Sat Jan  9 22:47:30 1999
From: halfmast at clubmet.metrobbs.com (halfmast at clubmet.metrobbs.com)
Date: Sat, 9 Jan 1999 16:47:30 -0500 
Subject: Summing node/S+H generator question
Message-ID: <TCPSMTP.19.1.9.-16.47.30.16623.2952@clubmet.metrobbs.com>


As my first experiment with sample and hold, I sampled some white noise
and applied the output to an attenuated CV input of my VCO.  A problem
arose as I lessened the attenuation.  A peak detector connected to the
summing amplifier of the VCO would register 2.5v (which is really only
half of the s+h's theoretical swing--it gives +-5v unattenuated), the
VCO's frequency would go up past an audible level, and then the peak
detector reads 12.5v. The thing is, the oscillator can handle such a
swing when my LFO is controlling it; so why can't I get the full
swing from the S+H?  I should probably also add that it would never
reach the high frequencies without becoming unstable, and that the S+H
never has problems when its not connected to the VCO.  Any ideas?
Thanks in advance for any input.

Evan Keller
halfmast at clubmet.metrobbs.com





From magnus at analogue.org  Sun Jan 10 00:53:22 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 10 Jan 1999 00:53:22 +0100
Subject: Summing node/S+H generator question
In-Reply-To: Your message of "Sat, 9 Jan 1999 16:47:30 -0500 "
References: <TCPSMTP.19.1.9.-16.47.30.16623.2952@clubmet.metrobbs.com>
Message-ID: <199901092353.AAA19539@mail2.it.kth.se>

>>>>> "h" == halfmast  <halfmast at clubmet.metrobbs.com> writes:

 h> As my first experiment with sample and hold, I sampled some white noise
 h> and applied the output to an attenuated CV input of my VCO.  A problem
 h> arose as I lessened the attenuation.  A peak detector connected to the
 h> summing amplifier of the VCO would register 2.5v (which is really only
 h> half of the s+h's theoretical swing--it gives +-5v unattenuated), the
 h> VCO's frequency would go up past an audible level, and then the peak
 h> detector reads 12.5v. The thing is, the oscillator can handle such a
 h> swing when my LFO is controlling it; so why can't I get the full
 h> swing from the S+H?  I should probably also add that it would never
 h> reach the high frequencies without becoming unstable, and that the S+H
 h> never has problems when its not connected to the VCO.  Any ideas?
 h> Thanks in advance for any input.

I come to think of the rise-time of the signal. What if the S/H will
have a real quick responce? What happends if you suddenly see a step
which has a very quick rise time and a step large enought, would you
bet that your filter would be stable under these conditions?

Try using some lowpass filter to dampen the risetimes, preferably a
variable filter so you can move close to the edge.

It is also worth noting that the behaviour that a curcuit has under
normal conditions and under high noise levels is apprechiably
diffrent. For instance will a high noiselevel at the input of the PLL
change the loopgain of that PLL to some degree dependent on the phase
detector responce. Nonlinearities like comparators etc start to behave
strangely. I say this to point out that noise is not just any signal,
it is a particularly mean signal to deal with.

Cheers,
Magnus



From removable at mediaone.net  Sun Jan 10 02:13:08 1999
From: removable at mediaone.net (removable at mediaone.net)
Date: Sat, 09 Jan 1999 19:13:08 -0600
Subject: SH09 service manual
References: <199901092115.TAA15180@postman.bahianet.com.br>
Message-ID: <3697FEA4.30000583@mediaone.net>

Edu Silva wrote:
> 
> My little SH09 (Roland) needs its service manual, or at least, a
> schematic. Can any of you guys help this unhappy synth?


The service manual is on the web in Adobe PDF format.
It's at http://www.electromusic.com/sc--__--__.html

Don



From budweiser at ozemail.com.au  Sun Jan 10 02:53:14 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Sun, 10 Jan 1999 12:23:14 +1030
Subject: Simple sample playback using EPROMs
Message-ID: <018301be3c3b$fd6a6d20$a0d26ccb@ppp.ozemail.com.au>



>
>There was an issue of Electronic Musician back in the late
>80's that featured such an article.  The project is probably
>simpler than you think because it didn't use a microcontroller
>at all.  You basically just need to reset and fire off a counter
>that drives the address lines on the EPROM every time you
>trigge the module.  Of course you'll also need a D/A converter
>connected to the data lines of the EPROM to reconstruct the
>audio....
>
>If I can find the issue I'll let you know.  I could possibly scan
>the schematic at work and email it to you....


Please do!!

Thanx,

<bUd>




From magnus at analogue.org  Sun Jan 10 05:07:28 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 10 Jan 1999 05:07:28 +0100
Subject: Moog Bp filter!
In-Reply-To: Your message of "Sun, 10 Jan 1999 02:27:44 -0800"
References: <369880A0.4DAD@swipnet.se>
Message-ID: <199901100407.FAA29574@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> Will the gentleman who told us about
 B> that he had made a BP filter out of a 
 B> Moog ladder please stand up!!

Well, if you mix the diffrential taps from the 3 top capacitors in
1:-2:1 you would end up with a BP filter from one ladder.

Actually you can make just about any responce you would fancy out of
that same ladder. LP, BP, HP, BS, AP, EQ, whatever. I have just done
the homework on that.

But then I recall that someone mentioned that he got a 904c filter
coupler that connects the 904a and 904b into an bandpass, but then you
are really using a LP ladder and a HP ladder.

Cheers,
Magnus



From mamundso at mr.net  Sun Jan 10 05:43:45 1999
From: mamundso at mr.net (Mark Amundson)
Date: Sat, 09 Jan 1999 20:43:45 -0800
Subject: day job...
References: <009101be3b89$154ed9c0$a0d26ccb@ppp.ozemail.com.au>
Message-ID: <36983001.C19@mr.net>

I'll take a step forward.

Hi, I am Mark Amundson and I am a licensed Electrical Engineer and work
for Guidant Corporation by day. My specialties are RF and Analog design
which I apply to the development next generation implantable cardiac
pacemakers and defibrillators.

When I am not working there, I write for Gig Magazine about technical
issues for professional musicians. On the weekends, I tend to be playing
keyboards and guitars in a local band. I got the DIY bug back in the
mid-seventies and was constructing projects from Craig Anderton's column
in Guitar Player Mag. I have published a couple of DIY projects in
Performer's Audio Magazine and will probably release a few more onto the
AMPAGE or AX84 websites. I also have worked with Tom Henry on products
for his Midwest Analog Products website.

Mark,



From vco at mindspring.com  Sun Jan 10 06:22:45 1999
From: vco at mindspring.com (tomg)
Date: Sun, 10 Jan 1999 00:22:45 -0500
Subject: Summing node/S+H generator question
In-Reply-To: <TCPSMTP.19.1.9.-16.47.30.16623.2952@clubmet.metrobbs.com>
Message-ID: <yam7679.2250.119102688@mail.mindspring.com>

On 09-Jan-99, halfmast at clubmet.metrobbs.com wrote:

>As my first experiment with sample and hold, I sampled some white noise
>and applied the output to an attenuated CV input of my VCO.  A problem
>arose as I lessened the attenuation.  A peak detector connected to the
>summing amplifier of the VCO would register 2.5v (which is really only
>half of the s+h's theoretical swing--it gives +-5v unattenuated), the
>VCO's frequency would go up past an audible level, and then the peak
>detector reads 12.5v. The thing is, the oscillator can handle such a
>swing when my LFO is controlling it; so why can't I get the full
>swing from the S+H?  I should probably also add that it would never
>reach the high frequencies without becoming unstable, and that the S+H
>never has problems when its not connected to the VCO.  Any ideas?
>Thanks in advance for any input.

>Evan Keller
>halfmast at clubmet.metrobbs.com


This works very well. Super simple sample and hold w/clock.

1 dual op-amp
2 fets
1 npn

http://www.mindspring.com/~vco/misc/ssh.html

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From irish at eskimo.com  Sun Jan 10 06:25:46 1999
From: irish at eskimo.com (Irish)
Date: Sat, 9 Jan 1999 21:25:46 -0800
Subject: Soldering from Hell. (was: Re: DSP Stuff)
References: <007901be3c10$d11af260$ce794e0c@hpcustomer>
Message-ID: <99010921295306.15936@Pandemonium>

On Sat, 09 Jan 1999, Arthur Harrison typed:
>Irish wrote:
>
>>OK, I'll shut up now....
>
>I write:
>
>No! Don't hold back!  It is really nice to have some 
>production folks like you on this list.  Gives a whole 
>lotta insight regarding the practical aspects of 
>electronics manufacturing, and that could never be 
>a bad thing.
>
>Art Harrison,
>Once a TH machine technician

Well, alright then. As long as you all don't mind me yakking about it, I will :)
That 8 years was a pretty wild ride through some very different types of places
(A lot of it was contract work - 'Iron for Hire'). 

Irish



From zzynt at swipnet.se  Sun Jan 10 11:27:44 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 10 Jan 1999 02:27:44 -0800
Subject: Moog Bp filter!
References: <4.1.19990109174046.00b10370@127.0.0.1>
Message-ID: <369880A0.4DAD@swipnet.se>

Will the gentleman who told us about
that he had made a BP filter out of a 
Moog ladder please stand up!!

BJ



From mark at spooky-solutions.co.uk  Sun Jan 10 11:42:19 1999
From: mark at spooky-solutions.co.uk (Mark Havard-Brown)
Date: Sun, 10 Jan 1999 10:42:19 -0000
Subject: day job...
Message-ID: <006401be3c86$175e68e0$ba8493c3@spookymb>

Computer/IT contractor based in the New Forest in England. I work on
Unix/OpenVMS/NT/Internet-Intranet systems - development and support.
Normally employed by financial institutions (banks, stockbrokers etc).
Played withs synths since my late teens, now almost forty (yip, I'm old and
sad).

Mark.






From irish at eskimo.com  Sun Jan 10 13:24:44 1999
From: irish at eskimo.com (Irish)
Date: Sun, 10 Jan 1999 04:24:44 -0800
Subject: Easy chip question
Message-ID: <99011004534208.15936@Pandemonium>

I'm trying to build a Midi thru box, and the diagram I have (which is
practically the only one out there!) has a chip drawn with each
out/thru port connected to individual inverter, plus one addtional at the
input end (sorry if the terms aren't right). 
My questions are: this chip (74LS244) has individual inverters, plus also has
additional inverters in it that chain the individual ones together by their
base (? I guess - they are drawn as a triangle, and this comes out the side).
Do I need to use these somehow? 
It confused me because the other chip I looked at for a similar
application (74LS05) did not have this 'chained together' piece. 

Also, (duh question) do I need to supply +V and gnd for the chip to work, or can
it be used as a passive(?) device? 

Sorry if these questions are kinda basic - it's amazing how much you can know
about something and still not know about it....

Thank you, 
Irish



From daniels at xs4all.nl  Sun Jan 10 13:46:28 1999
From: daniels at xs4all.nl (D. Schouten)
Date: Sun, 10 Jan 1999 13:46:28 +0100
Subject: day job...
Message-ID: <00ed01be3c9b$3219c660$a4856dc2@daniels.xs4all.nl>

I'm working at TBS ELECTRONICS as an electronics engineer in the field
of switch power supplies ranging from 1W to 3.5kW mostly DC to AC and
AC to DC converters.
SMPS design requires proper fundamental knowledge on analog circuit
design, magnetics design and the 'black magic' of EMI control. I must
say SMPS design can be quite exciting and I'm learning new things
almost every day.

Growing up in a family full of electronics enthousiasts I learned
soldering when I was ten years old and stuffed around with electronics
eversince. I'm also a great fan of electronic music and of course
electronic musical instruments. In my spare time I'm doing the TBS303
project.

Daniel...




From hhelland at usa.net  Sun Jan 10 14:23:47 1999
From: hhelland at usa.net (Hallgeir Helland)
Date: Sun, 10 Jan 1999 14:23:47 +0100
Subject: PCB layout software
Message-ID: <3698A9E3.E5AFAD3B@usa.net>

Hello,

What are you all using for PCB board layout?

I've just started on my synth-project at school, and
I'll be needing software to help me design the PCB's.
At school they have somthing called OrCAD, but it's
very complicated and nobody have used it for a long 
time. (so noone knows how it works.) So I'm looking 
for a simple but effective PCB/schematic tool. 

I visited the Protel web page, and I'll probably get
a time-limited demo version of their program. But
it probably costs a whole lot of money to register
it. 

So.... any suggestions? I'll be thankful. :-)

Hallgeir




From gmuir at sympatico.ca  Sun Jan 10 16:15:20 1999
From: gmuir at sympatico.ca (Gavin Muir)
Date: Sun, 10 Jan 1999 10:15:20 -0500
Subject: Strange source for SSM2040 ICs?
Message-ID: <199901101517.KAA29404@smtp11.bellglobal.com>

Hi all,

	As the guy who unkowingly started this "frenzy" for 2040s, I figure maybe
I should explain myself.

> Nevertheless, I think an SSM2040 is *not* worth 30 Dollars for a DIY
> project.
> I would surely spend 30 Dollars if Ihad a Rev. 2 Prophet with one defunct
> VCF 
> chip, because there is not much of an alternative. But for DIY ? That's
> insane.

	I agree. My interests were not solely for DIY (although the chip may find
a use until I have an emergency), as a few of my beasties which I treasure
use these. At that point, the concern that I would not find another supply
at a later date struck me when I found the $30 supply (which I agree is
excessive, although for DIY purposes no more excessive than $60 or so for a
single CEM3340 when I see them!)

> I just
> say don't buy them for that price for new projects, even if there are 400
> out there.
> You neither do yourself a favor (at that price), nor does it any good to
> Prophets
> and Kobols that might desperatly need one at some time.

	I agree. Hopefully the $30 premium will give people some pause.

> Just my opinion, of course. All I can offer is a free schematic of a
> replacement
> circuit (;->).

	Thanks for the work put into the discrete design Juergen. When I think I
can handle something with that many trannies, I'll probably build a version
which can have a permanent home in my modular!

Cheers,
Gavin Muir



From ben at stuyts.nl  Sun Jan 10 16:49:42 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 16:49:42 +0100
Subject: Filters
In-Reply-To: <1.5.4.32.19990109190653.0067a53c@pop3.demon.co.uk>
References: <1.5.4.32.19990109190653.0067a53c@pop3.demon.co.uk>
Message-ID: <199901101549.QAA01125@daneel.stuyts.nl>

On Sat, 09 Jan 1999, James Jackson wrote:

> Yes, I am designing a Physical Modelling synth. See:
>
> http://www.newd.demon.co.uk/dsp/

Looks interesting. Any idea when you will start implementing it?

> The filters will be based around Fourier Transform algorithms, so I'll have
> to teach myself how to do Fourier Transforms! Yes, they  have the usual
> 'Analog Style' controls, as I want to make my synth as Analog as possible.

If I understand you correctly you want to do an fft on the signal, then in  
the frequency domain do the filtering, and then reverse fft back to the audio  
signal? You'll be having a lot of fun with that. An important problem is that  
you'll have to do this on multiple overlapping windows, using some sort of  
windowing functions. Otherwise, you'll get audible clicks at the points where  
one fft starts and the next one ends. Also important is the choice of the size  
of your fft.

Wouldn't a more conventional filter type (FIR or IIR) be more practical for this?

> James Jackson - New Era Web Designs |

BTW, I looked at http://www.newd.demon.co.uk/ and all I got was "Please Wait,  
determining browser type...". There it ended. (Hint: there's more to life  
than Netscape, Internet Explorer and Javascript.) Not very good advertizing  
for somebody who has Web Designs in his signature. B-)

Best regards,
Ben



From ben at stuyts.nl  Sun Jan 10 17:17:09 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 17:17:09 +0100
Subject: Digital DIY synths?
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D6863@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6863@demon>
Message-ID: <199901101617.RAA01145@daneel.stuyts.nl>

On Fri, 8 Jan 1999, Roman Sowa wrote:

> I can't say 16-bit A/D/As are expensive. I buy them for 4-10$, and they
> sometimes are dual (or stereo if you like)

What kind do you use? Any comments on their sound quality?

> As for DAC-based envelope - in my Poly i use 7-bit control voltage, and
> when I tweek, say VCF cutoff, the steps are not only noticable,
> but anoying

10 bit would probably be more than enough for this kind of stuff, right?

Best regards,
Ben



From ben at stuyts.nl  Sun Jan 10 17:23:07 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 17:23:07 +0100
Subject: Digital DIY synths?
In-Reply-To: <yam7677.2622.119073040@mail.mindspring.com>
References: <yam7677.2622.119073040@mail.mindspring.com>
Message-ID: <199901101623.RAA01151@daneel.stuyts.nl>

On Fri, 08 Jan 1999, tomg wrote:

> >I found the Yamaha An1x, which I could try out over the
> >holiday. (Yep, gonna keep it!) The whole DSP thing started to make more and
> >more sense to me. Not to mention being able to use it polyphonically.
>
> Yeah! I spent a little time with this the other day. Pretty
> good, the nord has a lot more edge but I like the sound of
> the JP-8K best. If your going to buy a DSP machine check it
> out first.

Did that too, but didn't like it. The Roland has only a 4 octave keyboard,  
which is not enough for me. Also no aftertouch I think, but I do not consider  
that very important. The JP8000 does have a few more knobs though. The other  
day I found a patch file for the Yamaha An1x with all the JP8000 sounds. B-)  
Can't really compare them as I don't have a JP8000 handy.

I also played a Nord Lead, but was very disappointed with it. The sound  
didn't do much to me, and the controls and keyboard were awful.

My favorite was the Access Virus, but it is quite a bit more expensive, and  
as it is only a module I'd have to buy another master keyboard.

> I think it's interesting that all this DSP stuff sounds very
> different depending on the name plate.

Yeah, that's good. It just means that you can have just as many different  
characters in dsp based synths as you have in analog based ones. It goes  
contrary to the myth that all this digital stuff sounds the same.

Best regards,
Ben



From ben at stuyts.nl  Sun Jan 10 17:27:02 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 17:27:02 +0100
Subject: Digital DIY synths?
In-Reply-To: <yam7677.412.118764312@mail.mindspring.com>
References: <yam7677.412.118764312@mail.mindspring.com>
Message-ID: <199901101627.RAA01159@daneel.stuyts.nl>

On Fri, 08 Jan 1999, tomg wrote:

> >I think it's interesting that all this DSP stuff sounds very
> >different depending on the name plate.
>
> I should also say the filter functions on most of this stuff
> leaves me feeling unsatisfied!

I wonder if that has anything to do with the fact that you have to be  
conservative in your dsp filtering code. I mean, if you turn up the resonance  
there is a pretty good chance that you run out of headroom. So clipping (or  
worse: wrapping) will occur, and digital clipping isn't very musical.

> It's possible some sort of hybrid
> would be really cool.

>From a previous message from Roman Sowa I understand that the Waldorf Pulse  
does that.

Best regards,
Ben



From cyborg0 at GlobalEyes.net  Sun Jan 10 17:28:52 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 10 Jan 1999 10:28:52 -0600
Subject: PCB layout software
References: <3698A9E3.E5AFAD3B@usa.net>
Message-ID: <3698D544.1BD1BF0C@globaleyes.net>

Hallgeir Helland wrote:
> 
> Hello,
> 
> What are you all using for PCB board layout?
> 
> I've just started on my synth-project at school, and
> I'll be needing software to help me design the PCB's.
> At school they have somthing called OrCAD, but it's
> very complicated and nobody have used it for a long
> time. (so noone knows how it works.) So I'm looking
> for a simple but effective PCB/schematic tool.
> 
> I visited the Protel web page, and I'll probably get
> a time-limited demo version of their program. But
> it probably costs a whole lot of money to register
> it.
> 
> So.... any suggestions? I'll be thankful. :-)
> 
> Hallgeir

EAGLE PCB is the easiest and the best and has a full working demo
version.. wonderful software..
Rob



From ben at stuyts.nl  Sun Jan 10 17:29:39 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 17:29:39 +0100
Subject: DSP Stuff
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D6868@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6868@demon>
Message-ID: <199901101629.RAA01162@daneel.stuyts.nl>

On Fri, 8 Jan 1999, Roman Sowa wrote:

> (I had an discount offer for just 1k$), but I'd rather spend it
> on Yamaha AN1x and tweek it ;-)

Do you really think there's something to tweek inside the AN1x? I wonder.  
Will have to open it one of these days. B-)

Best regards,
Ben



From cyborg0 at GlobalEyes.net  Sun Jan 10 17:30:47 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 10 Jan 1999 10:30:47 -0600
Subject: day job...
References: <00ed01be3c9b$3219c660$a4856dc2@daniels.xs4all.nl>
Message-ID: <3698D5B7.54D49070@globaleyes.net>

"D. Schouten" wrote:
 In my spare time I'm doing the TBS303
> project.
> 
> Daniel...

Ok, Daniel, From the availability of the tbs303, I guess you havent much
free time then! ;)
Rob



From cyborg0 at GlobalEyes.net  Sun Jan 10 17:57:24 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 10 Jan 1999 10:57:24 -0600
Subject: Rubber button supply
References: <ebcff200.3697c1d6@aol.com>
Message-ID: <3698DBF4.55E900AD@globaleyes.net>

Well, I found a place called ARC-USA that will sell rubber buttons for
experimenters and modders! www.arc2.arcpv.com

For those applications where space is crucial, these buttons are a MUST!
They are also really neat in that you can use just about anything as a
button with these, because you merely need something to fit in the
button hole so that you can press down the conductive rubber. E-switch
has some really neat chrome plated button covers for cheap. To add to
the conductivity, you can also get nickel or gold contactors underneath
rather than the carbon.

One question though: I see on a lot of gear where the PCB trace is
coated with carbon where it contacts the rubber button. Does anyone know
if you can get some sort of mixture or conductive glue to glue the
carbon to the traces? 
I *think* this is the very reason why MMT-8s button overlay goes bad. I
don't recall seeing carbon on the PCB contact pads.


	I guess it will work ok with just the copper, but copper tends to
oxidize after a time. Maybe just using the old trick of glueing aluminum
foil on the bottom of the button will work.

Rob



From ben at stuyts.nl  Sun Jan 10 18:00:16 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 18:00:16 +0100
Subject: DSP Stuff: floating point or fixed point
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D686C@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D686C@demon>
Message-ID: <199901101700.SAA01185@daneel.stuyts.nl>

On Sat, 9 Jan 1999, Roman Sowa wrote:

> Say, what?...
> Not satisfied with IEEE floating point format? Why not use
> 40-bit floats in SHARC. And you can also use it as 32-bit
> fixed poit DSP

I think one of the points being made was that you need to have a high  
precision accumulator. Like the Motorola 56k series: fixed point 24 bit data,  
but 56 bit results. That gives you lots of headroom. With the SHARC I think  
you are limited to 32 or 40 bits, right?

Best regards,
Ben



From mwmjr at ix.netcom.com  Sun Jan 10 19:19:19 1999
From: mwmjr at ix.netcom.com (Michael Maloney)
Date: Sun, 10 Jan 1999 13:19:19 -0500
Subject: DSP Stuff: floating point or fixed point
Message-ID: <3.0.5.32.19990110131919.007aa7a0@popd.ix.netcom.com>

>I think one of the points being made was that you need to have a high  
>precision accumulator. Like the Motorola 56k series: fixed point 24 bit
data,  
>but 56 bit results. That gives you lots of headroom. With the SHARC I think  
>you are limited to 32 or 40 bits, right?

The accumulator on the 21061 is 80-bit.


Maloney



From ijfritz at earthlink.net  Sun Jan 10 19:57:28 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sun, 10 Jan 1999 11:57:28 -0700
Subject: day jobs
References: <002b01be3d83$6db45ee0$d438883e@default>
Message-ID: <3698F818.41F99822@earthlink.net>


research physicist -- govt. lab

  Ian



From mirwin1 at istar.ca  Sun Jan 10 20:01:38 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Sun, 10 Jan 1999 14:01:38 -0500
Subject: DIY Surface Mount Soldering
References: <99010905122804.15936@Pandemonium>
Message-ID: <3698F911.C527D173@istar.ca>

It is possible to solder tiny SMD parts using ordinary  equipment if you
have a steady hand, good eyes, a magnifier and patience. I use a cheap
Radio Shack 15 watt soldering iron. File down the (interchangeable) tip
to a needle point and use fine gauge wire solder. Align the chip on the
PCB (with the help of a magnifier) and hold it in place by soldering a
pin at each corner. I have soldered (and replaced) 100-pin QFP (flat
pack) microcontrollers on many occasions using these tools. When solder
bridges occur between pins (as FREQUENTLY happens) use a fine-braid
solder wick to remove the excess solder. The remaining solder will be
enough to secure the pin to the pad.

To remove a QFP a special tool that heats up all pins at once is best.
Otherwise use a very sharp knife to gently cut the pins off each side
to remove a defective chip, and desolder the remains of each pin. The
biggest risk here is peeling the tiny pads off the PCB. Adapters are
available for a number of  many-pin flat packs which have sockets for
the chip and PCB pads or wire-wrap pins for connecting to a main board.
By the way, most DSP evaluation boards have connectors to bring out
control and data lines for interfacing to a larger system. The
difficult-to-do soldering has already been done for you on the board.




From ben at stuyts.nl  Sun Jan 10 21:32:28 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Sun, 10 Jan 99 21:32:28 +0100
Subject: Filters
In-Reply-To: <1.5.4.32.19990110181326.00675cb8@pop3.demon.co.uk>
References: <1.5.4.32.19990110181326.00675cb8@pop3.demon.co.uk>
Message-ID: <199901102032.VAA01315@daneel.stuyts.nl>

On Sun, 10 Jan 1999, James Jackson wrote:

> >Wouldn't a more conventional filter type (FIR or IIR) be more practical for
> this?
>
> Do you know where I can get information on performing these types of
> filtering?

I've cc'd the list as this might be useful to others. Yes, there's a *great*  
site with a DSP tutorial on it. Look on www.bores.com. There is probably a  
link on their main page.

> >(Hint: there's more to life
> >than Netscape, Internet Explorer and Javascript.) Not very good advertizing
> >for somebody who has Web Designs in his signature. B-)
>
> Yes, what browser are you using? If it is not netscape 4 it should go to
> 'ns3index.htm' and if it is NS 4, it should go to 'ns4index.htm'.

OmniWEB (v2.7 I think) on NeXTSTEP.

Best regards,
Ben



From a-davidh at microsoft.com  Sun Jan 10 21:37:29 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Sun, 10 Jan 1999 12:37:29 -0800
Subject: day job
Message-ID: <C35556591D34D111BB5600805F1961B90BBEAF6F@RED-MSG-47>

I manage a software test lab for Microsoft.  http://www.microsoft.com/data/

Our group doesn't do any database programming languages per se. ( FoxPro,
SQL Server, Access... ) but we do all of the "glue" that allows other
programs to access databases.  If you write something in C++ or Visual Basic
that talks to an Oracle or SQL database, you are using our bits.

It's a lot of fun - I have been working here for about two years.  The lab
has over 300 computers ranging from 486's ( hey - we have to make sure it
will run anywhere ) up to 4-proc Xeon and 8-proc PPro mega servers.
Operating systems range from Windows95, 98, NT & Windows 2000 ( the new
offering )

Basically, I pound on one kind of keyboard all day and then go home and
pound on another kind of keyboard for relaxation...

Dave Halliday	( Cc... MSPAGE )
B2/2132  /  2121	office  /  lab
x20161	voice




From cyborg0 at GlobalEyes.net  Sun Jan 10 21:38:31 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 10 Jan 1999 14:38:31 -0600
Subject: Rubber button supply
References: <ebcff200.3697c1d6@aol.com> <3698DBF4.55E900AD@globaleyes.net>
Message-ID: <36990FC7.1FB9CE33@globaleyes.net>

Rob wrote:
> 
> Well, I found a place called ARC-USA that will sell rubber buttons for
> experimenters and modders! www.arc2.arcpv.com
> 
Oops.. that won't work.. here it is..
http://arc2.arcpv.com/stdprice.htm
This will get you to the price list
rob



From a-davidh at microsoft.com  Sun Jan 10 21:40:00 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Sun, 10 Jan 1999 12:40:00 -0800
Subject: DIY Surface Mount Soldering
Message-ID: <C35556591D34D111BB5600805F1961B90BBEAF70@RED-MSG-47>

I forget the brand name but there is a very clever solder out there for
desoldering SMD parts.  It has a lot better "wetting" ability than standard
solder but has almost zero mechanical strength.  

You reflow this solder onto the pins, it displaces the old solder and then
you can pick the part off the board with ease.

I ran into this in one of Don lancaster's columns - www.tinaja.com



-----Original Message-----
From: Michael B. Irwin [mailto:mirwin1 at istar.ca]
Sent: Sunday, January 10, 1999 11:02 AM
To: irish at eskimo.com
Cc: DIY
Subject: DIY Surface Mount Soldering


It is possible to solder tiny SMD parts using ordinary  equipment if you
have a steady hand, good eyes, a magnifier and patience. I use a cheap
Radio Shack 15 watt soldering iron. File down the (interchangeable) tip
to a needle point and use fine gauge wire solder. Align the chip on the
PCB (with the help of a magnifier) and hold it in place by soldering a
pin at each corner. I have soldered (and replaced) 100-pin QFP (flat
pack) microcontrollers on many occasions using these tools. When solder
bridges occur between pins (as FREQUENTLY happens) use a fine-braid
solder wick to remove the excess solder. The remaining solder will be
enough to secure the pin to the pad.

To remove a QFP a special tool that heats up all pins at once is best.
Otherwise use a very sharp knife to gently cut the pins off each side
to remove a defective chip, and desolder the remains of each pin. The
biggest risk here is peeling the tiny pads off the PCB. Adapters are
available for a number of  many-pin flat packs which have sockets for
the chip and PCB pads or wire-wrap pins for connecting to a main board.
By the way, most DSP evaluation boards have connectors to bring out
control and data lines for interfacing to a larger system. The
difficult-to-do soldering has already been done for you on the board.



From guidogoe at xs4all.nl  Sun Jan 10 21:48:22 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Sun, 10 Jan 1999 20:48:22 GMT
Subject: Digital DIY synths?
References: <199901101627.RAA01159@daneel.stuyts.nl>
Message-ID: <915997812-050418AEicMi@xs4all.nl>

Ben wrote:

>I wonder if that has anything to do with the fact that you have to be conservative in your dsp filtering code. I mean, if you turn up the resonance there is a pretty good chance that you run out of headroom. So clipping (or worse: wrapping) will occur, and digital clipping isn't very musical.

I'm studying DSP-filters the last few months. I'm working on a Atari030
which has a Motorola 56001 DSP on board, as well as a 16Bit ad/da stereo CODEC, I think made by Crystal.
The whole system is capable of 8 channel/50Khz sampling/processing.
I haven't learned that much yet, but I recall there were some window coefficients necessary to keep the filter-things within range.
Not much help I quess...
Anybody else working on a Falcon out there?

Guido...




From oakley at techrepairs.freeserve.co.uk  Sun Jan 10 21:49:39 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Sun, 10 Jan 1999 20:49:39 -0000
Subject: 3340 sync
Message-ID: <001401be3d82$85e25cc0$d438883e@default>

Colin wrote:
The E&MM Spectrum synth, which uses 3340s, uses an external FET which
resets
the voltage on the timing cap directly.



Bloody brill this one. Total mayhem. Oh and don't forget to add linear
FM at the same time. Mind you, the extra tranny with a pair of 3340s is
quite good anyhow, similar to the Rogue but maybe not quite as cutting.
But as Juergen says why not have both.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From daniels at xs4all.nl  Sun Jan 10 22:08:17 1999
From: daniels at xs4all.nl (D. Schouten)
Date: Sun, 10 Jan 1999 22:08:17 +0100
Subject: [OT] Midi via PC serial port
Message-ID: <002501be3cdd$59df54c0$f2876dc2@daniels.xs4all.nl>

Hi all,

I'm looking for a Windows driver which can output midi data on a
serial
comm port of my PC.
Anyone ever heard of such a driver?

Thanks.

Daniel




From LEG at btinternet.com  Sun Jan 10 23:01:31 1999
From: LEG at btinternet.com (george & lorraine)
Date: Sun, 10 Jan 1999 22:01:31 -0000
Subject: re day job
Message-ID: <01be3ce4$c8091100$bdfdabc3@windows95>

Explosive's technician and general nasty thing's put it together merchant in
sunny old U.K. (well you gotta relax between music session's aint ya!!)

George

8 track man,Bath,England.




From alexandr at irit.fr  Sun Jan 10 23:24:38 1999
From: alexandr at irit.fr (Karl ALEXANDRE)
Date: Sun, 10 Jan 1999 23:24:38 +0100
Subject: PCB layout software
References: <3698A9E3.E5AFAD3B@usa.net> <3698D544.1BD1BF0C@globaleyes.net>
Message-ID: <369928A6.C2445269@irit.fr>

> EAGLE PCB is the easiest and the best and has a full working demo
> version.. wonderful software..
> Rob

	I agree, it's very intuitive and easy to lurn. It takes me
	3 minutes to add an IC which is not in the libraries...
	Unless you don't use the auto-router, it is perfect. This is
	the one for homebrew projects.



	Karl.



From jamos at technotoys.com  Sun Jan 10 23:33:52 1999
From: jamos at technotoys.com (Jim Johnson)
Date: Sun, 10 Jan 1999 14:33:52 -0800
Subject: [OT] Midi via PC serial port
In-Reply-To: <002501be3cdd$59df54c0$f2876dc2@daniels.xs4all.nl>
References: <002501be3cdd$59df54c0$f2876dc2@daniels.xs4all.nl>
Message-ID: <199901101433520420.0549B6A0@smtp.transport.com>

>I'm looking for a Windows driver which can output midi data on a
>serial
>comm port of my PC.
>Anyone ever heard of such a driver?

Check over at www.maxmidi.com - I think he has one, along with a DIY
project for the hardware. Might be bad memory on my part, but I think he's
got it.

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 1/10/99, at 5:06 PM, D. Schouten wrote: 

>Hi all,
>
>I'm looking for a Windows driver which can output midi data on a
>serial
>comm port of my PC.
>Anyone ever heard of such a driver?
>
>Thanks.
>
>Daniel



From a-davidh at microsoft.com  Mon Jan 11 01:01:49 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Sun, 10 Jan 1999 16:01:49 -0800
Subject: PCB layout software
Message-ID: <C35556591D34D111BB5600805F1961B90BBEAF7A@RED-MSG-47>

I just spent a lot of time going over several packages and Eagle was the one
for me too...  EdWin is a close second but it seems to be more oriented
towards large group efforts.

MicroCode CircuitMaker and TraxMaker are cute but don't really have the full
package.  They tout a built-in analog simulation and Spice capability but
they only have +10 and +5 voltages, no +15 and NO -15!!!  Analog my
patootie!  The manual states that these can be built but I don't see why I
should have to build something as basic as this...

Ivex is good but I liked Eagle better.

I had also bought a copy of Tango PCB and Schematic capture at an auction
but I got the package minus the dongle.  I called the company, told them the
situation, told them that I had the original manuals, the original bill of
sale to the parent company, the original disks and my bill of sale from the
auctioneer.  I just needed the dongle and the older version of the software
would be fine for my needs.  

They told me that I had to upgrade to the current version to get a new
dongle and that was about $1,400  -  I will not ever consider dealing with
that company again...

-----Original Message-----
From: Karl ALEXANDRE [mailto:alexandr at irit.fr]
Sent: Sunday, January 10, 1999 2:25 PM
To: synth-diy at mailhost.bpa.nl
Subject: Re: PCB layout software


> EAGLE PCB is the easiest and the best and has a full working demo
> version.. wonderful software..
> Rob

	I agree, it's very intuitive and easy to lurn. It takes me
	3 minutes to add an IC which is not in the libraries...
	Unless you don't use the auto-router, it is perfect. This is
	the one for homebrew projects.



	Karl.



From IXQY at aol.com  Mon Jan 11 02:00:42 1999
From: IXQY at aol.com (IXQY at aol.com)
Date: Sun, 10 Jan 1999 20:00:42 EST
Subject: day jobs
Message-ID: <c36fbc3c.36994d3a@aol.com>

 Hello,  
  I'm an electronic tech for Sony Semiconductor. I work in the Test Department
keeping the machines that test each die running to spec. This is the final
stage of the wafer fab process (other than final visual inpsection and
packaging).
 I was considering quitting my job in order to commit more to the band that I
recently joined. The CD is drawing great response on a worldwide level for
this style of music (prog rock/metal). After doing some reading though, I'm
finding out that musicians are not paid as well as I previously thought, even
if the release sells well.
 So I guess it's back to work this week.....
 
 Andrew Sanchez

 P.S. Feel free to email me privately if you have any thoughts on the business
aspect of the music industry. thanks



From vco at mindspring.com  Mon Jan 11 05:51:33 1999
From: vco at mindspring.com (tomg)
Date: Sun, 10 Jan 1999 23:51:33 -0500
Subject: PCB layout software
In-Reply-To: <C35556591D34D111BB5600805F1961B90BBEAF7A@RED-MSG-47>
Message-ID: <yam7679.1664.119057568@mail.mindspring.com>

What it the deal with the old DOS version of Protel's
EasyTraks.

One of the guys on the list sent me a copy of V2.06 and 
told me it was free. I've heard others say the same thing.

I really don't care at this point you would have to fight
me and win to get it away now.

It's 10 years old but this thing ROCKS! I tried all of that 
windows crap doing the MM pcb and it just didn't do it for 
me. Most of the time would NOT! do it for me.

Once I got into it ET was great! It's easy to add to the lib
most of the stuff was all ready there. Way fast! Gerber and
postscript output.

Anyway if it really is free you guys should grab a copy.
I like it...a lot!

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From vco at mindspring.com  Mon Jan 11 05:53:30 1999
From: vco at mindspring.com (tomg)
Date: Sun, 10 Jan 1999 23:53:30 -0500
Subject: [OT] Midi via PC serial port
In-Reply-To: <002501be3cdd$59df54c0$f2876dc2@daniels.xs4all.nl>
Message-ID: <yam7679.1506.119057568@mail.mindspring.com>

On 10-Jan-99, D. Schouten wrote:
>Hi all,

>I'm looking for a Windows driver which can output midi data on a
>serial
>comm port of my PC.
>Anyone ever heard of such a driver?

>Thanks.

>Daniel

Yep...The Yamaha TG-100 driver shoots midi out the serial
port. DL it from Yamaha.

-tg


-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From vco at mindspring.com  Mon Jan 11 05:54:05 1999
From: vco at mindspring.com (tomg)
Date: Sun, 10 Jan 1999 23:54:05 -0500
Subject: DIY Surface Mount Soldering
In-Reply-To: <C35556591D34D111BB5600805F1961B90BBEAF70@RED-MSG-47>
Message-ID: <yam7679.291.119057568@mail.mindspring.com>

On 10-Jan-99, David Halliday (Volt Computer) wrote:
>I forget the brand name but there is a very clever solder out there for
>desoldering SMD parts.  It has a lot better "wetting" ability than standard
>solder but has almost zero mechanical strength.  

>You reflow this solder onto the pins, it displaces the old solder and then
>you can pick the part off the board with ease.

>I ran into this in one of Don lancaster's columns - www.tinaja.com

It melts at a very low temp. So you just run it arround the edges
of the SMD and push it off the board. I bought some from Projector
Belt to replace the DSP in my S01. Works great! 

BTW had to buy a weller princess to put it back on and
it's still working.

-tg



-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From jlarryh at iquest.net  Mon Jan 11 06:07:17 1999
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Sun, 10 Jan 1999 23:07:17 -0600
Subject: PCB software
Message-ID: <199901110401.FAA08671@mailhost.bpa.nl>

EAGLE PCB is the easiest and the best and has a full working demo
> version.. wonderful software..

Where might one find a copy of the demo version of this software?
Larry Hendry



From stew at uq.net.au  Mon Jan 11 07:31:11 1999
From: stew at uq.net.au (Stewart Pye)
Date: Mon, 11 Jan 1999 17:31:11 +1100
Subject: M6530 delay IC
Message-ID: <199901110736.RAA06716@uq.net.au>

Hi All,

A local electronics store has some M6530P delay chips for a reasonable
price. I cant find any info on this chip. Does anyone know anything about
them or where I could find the data sheet??

Thanks,

Stewart Pye




From vco at mindspring.com  Mon Jan 11 08:15:58 1999
From: vco at mindspring.com (tomg)
Date: Mon, 11 Jan 1999 02:15:58 -0500
Subject: OT: Cringely HAHAHA
Message-ID: <yam7680.2911.119247600@mail.mindspring.com>

I know (based on the recent day job disclosures) that some
of you get Info Week. Cringely cracks me up every time.

His predictions for 1999 include Netscape and Microsoft
actually suporting the same web standards at the same
time. No truth to the rumor it's in responce to the 
class action lawsuit filed by angry web developers. 
snicker....

Microsoft releases Office 2000 for Linux. Planning a 
full demonstration of the new product because they
don't expect any system crashes. HAHAHAHAHA!!!

Apple's working full time to deliver the backlog
of corporate orders for the iMac. Jobs says he's
completely suprised IT departments are going with
Mac OS X rather than wait for Win2000's delivery
sometime in late 2001.

hehe..he..heheheh

It's much funnier in Info Week. I just stole the best
bits for the folks who can't get Info Week. It's hard
to come by if your not in the industry up to your
eyeballs. 

I can't prove it but I think this guy is the infamous
Bandeedo. If you are clueless to this referance, you
are probibly in the majority.

It's gona be a Great Year!

-tg

BTW picked up a Quadra 605 040/55 80mhd/16mm OS 7.1
for $20. All of my old Mac software is very happy. Got
Netscape installed gona pick up a modem cable tomorrow.
I don't think the person who sold it to me had a hint
of a clue.

I still think the Mac's timing feels the best for midi. 
I gota big'ol southern grin in Atlanta.

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From don at till.com  Mon Jan 11 08:21:46 1999
From: don at till.com (Don Tillman)
Date: Sun, 10 Jan 1999 23:21:46 -0800 (PST)
Subject: day job
Message-ID: <199901110721.XAA01828@shell9.ba.best.com>

I'm a senior software engineer at a small startup company called
Marimba, Inc.  We make some interesting packages for distributing,
licensing and updating software products over the internet.  I've been
working in Java for the last three years, mostly Lisp before that.

I moved from electrical engineering to software engineering 12 years
ago, roughly the time "the building blocks changed" and most
processors and subsystems were put on chips.

  -- Don






From martin.czech at intermetall.de  Mon Jan 11 08:38:13 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 11 Jan 1999 08:38:13 +0100 (MET)
Subject: day job
Message-ID: <199901110738.IAA24854@window.intermetall.de>

Back to work in 1999.

Happy new year for all!

I'm a design engineer at Micronas Intermetall, I design CMOS digital
(sometimes also analog) circuits, mostly for controller ICs (6502 based).
I also take care of the design of the companys ESD-protection structures.
So far I worked only on little ICs, say 500.000 transistors, so one man,
one IC, no team.


m.c.




From budweiser at ozemail.com.au  Mon Jan 11 08:39:08 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Mon, 11 Jan 1999 18:09:08 +1030
Subject: PCB layout software
Message-ID: <001701be3d35$79df7040$6ba66ccb@ppp.ozemail.com.au>


Where can i get this? Could someone please email it to me?

<bUd>


>What it the deal with the old DOS version of Protel's
>EasyTraks.
>
>One of the guys on the list sent me a copy of V2.06 and 
>told me it was free. I've heard others say the same thing.
>
>I really don't care at this point you would have to fight
>me and win to get it away now.
>
>It's 10 years old but this thing ROCKS! I tried all of that 
>windows crap doing the MM pcb and it just didn't do it for 
>me. Most of the time would NOT! do it for me.
>
>Once I got into it ET was great! It's easy to add to the lib
>most of the stuff was all ready there. Way fast! Gerber and
>postscript output.
>
>Anyway if it really is free you guys should grab a copy.
>I like it...a lot!
>
>-tg
>
>-------------------------------------------------
>  Mad Mouse - PC Boards - Analog For Everybody
>http://www.mindspring.com/~vco/madm/mm_order.html
>-------------------------------------------------
>
>




From jorgen.bergfors at idg.se  Mon Jan 11 08:49:33 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 11 Jan 1999 8:49:33 +0100
Subject: PCB layout software
Message-ID: <TFSGZWEU@idg.se>

I use Corel Draw both for PCBs and schematics. It is of course completely manual, but the automatic routing programs won't give you optimised results anyway. I have found that I can do quite a bit more compact boards with fewer wire links than the automatic programs. It is actually rather fun. A bit like laying a puzzle. Another big advantage is that you don't have to learn another program. A general drawing program can be used to so many other things. I design and print my front panel layouts with it too.

/Jorgen




MIME:hhelland at usa.net on 99-01-10 15:31:25
To:  synth-diy at mailhost.bpa.nl @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: PCB layout software 

Hello,

What are you all using for PCB board layout?

I've just started on my synth-project at school, and
I'll be needing software to help me design the PCB's.
At school they have somthing called OrCAD, but it's
very complicated and nobody have used it for a long time. (so noone knows how it works.) So I'm looking for a simple but effective PCB/schematic tool. 

I visited the Protel web page, and I'll probably get
a time-limited demo version of their program. But
it probably costs a whole lot of money to register
it. 

So.... any suggestions? I'll be thankful. :-)

Hallgeir










From alexandr at irit.fr  Mon Jan 11 08:56:27 1999
From: alexandr at irit.fr (Karl ALEXANDRE)
Date: Mon, 11 Jan 1999 08:56:27 +0100
Subject: PCB software
References: <199901110401.FAA08671@mailhost.bpa.nl>
Message-ID: <3699AEAA.D9686B56@irit.fr>

> Where might one find a copy of the demo version of this software?
> Larry Hendry

	The home of Eagle is something like www.cadsoft.de or 
	an url like this...

	Karl.



From djblue at asu.edu  Mon Jan 11 09:23:36 1999
From: djblue at asu.edu (Reverend bluE)
Date: Mon, 11 Jan 1999 01:23:36 -0700 (MST)
Subject: PCB layout software
In-Reply-To: <3698D544.1BD1BF0C@globaleyes.net>
Message-ID: <Pine.GSO.3.96.990111012231.14972E-100000@general1.asu.edu>


Rob wrote:
> EAGLE PCB is the easiest and the best and has a full working demo
> version.. wonderful software..

and I inquire:

 is this for PC?  (it probably is, so on to my next q)  is there any PCB
design software for Macs?
-ben




From brun at bart.nl  Mon Jan 11 09:53:56 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Mon, 11 Jan 1999 09:53:56 +0100
Subject: Website help needed! Looking for schematics links
Message-ID: <199901110854.JAA29408@smtp1.xs4all.nl>

 am attempting to write a comprehensive listing of all the 
schematics and manuals that are readily available on the web. A 
first attempt can be found on http://www.bart.nl/~brun/index.htm, 
go to the Schematics-DIY section of the site. It's meant to help 
finding the right documentation for analog synths. As for me, I 
always have to spend hours on the web before I find the scanned 
schematic I need, if there is any. 

Your input is appreciated and needed! I will list all links to scanned 
or 'webbed' manuals, viewable or downloadable schematics and 
repair-FAQs concerning commercial analog synthesizers. Please 
mail me your suggestions, and include a short description of the 
synths that are covered. Of course I'll only link to the sites, to avoid 
bandwith theft and to give full credit to the owners.

You can send your suggestions to brun at bart.nl.

Thanks,

Jeroen



-> Brun, met een dakje op de u.

Nu aan het knutselen op http://www.bart.nl/~brun/index.htm



From vco at mindspring.com  Mon Jan 11 10:08:07 1999
From: vco at mindspring.com (tomg)
Date: Mon, 11 Jan 1999 04:08:07 -0500
Subject: MM Assembly and Setup Manual
Message-ID: <yam7680.371.120625320@mail.mindspring.com>

I replaced all of the Mad Mouse files. It is now the 
assembly and setup manual in html form. Fairly 
represenitive of the DTP document I intend to include 
with the MM. Includes a new parts list and wiring
diagram, lots more.

I will put pics back up when the boards come in and I
can complete the referance unit.

If you bought a MM you can get a head start.

http://www.mindspring.com/~vco/madm/title.html

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From beszedes at cc.u-szeged.hu  Mon Jan 11 10:48:53 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Mon, 11 Jan 1999 10:48:53 +0100
Subject: day jobs
References: <002b01be3d83$6db45ee0$d438883e@default>
Message-ID: <3699C905.28CBD993@cc.u-szeged.hu>


Tony Allgood wrote:
> Before that I was a teacher. And before that I designed Soundcraft
> mixers.

Hello Tony (all),

I understand that you probably know everything about mixers, equlizers,
etc. I would like to build for myself a 6-8 channel home-studio mixer
which has e.g. the following controls for each channel: gain, 3-channel
equ, pan, effect, volume. So I'm looking for some schematics,
(relatively good quality -> fet opamps?). Could you help me?

Thanks in advance,

Arpad.

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************



From rsowa at WizjaTV.pl  Mon Jan 11 10:54:39 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 11 Jan 1999 10:54:39 +0100
Subject: ODP: Filters
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6879@demon>

Hi,
good luck on this project...
It's nice as soon as you'll manage to do it all

Could you specify what you mean by Fourier Transform based filters?

Roman

> -----Oryginalna wiadomo??-----
> Od:	James Jackson [SMTP:james at newd.demon.co.uk]
> Wys?ano:	9 stycznia 1999 20:07
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	Re: Filters
> 
> Yes, I am designing a Physical Modelling synth. See:
> 
> http://www.newd.demon.co.uk/dsp/
> 
> for details of it so far.
> 
> The filters will be based around Fourier Transform algorithms, so I'll
> have
> to teach myself how to do Fourier Transforms! Yes, they  have the usual
> 'Analog Style' controls, as I want to make my synth as Analog as possible.
> 
> -JJ
> --------------------------------------------------------------------------
> -----
> James Jackson - New Era Web Designs
>           |
>           ------------------- james at newd.demon.co.uk
> Sales ------------------- sales at newd.demon.co.uk
> Information ------------ info at newd.demon.co.uk
> 
> Website ---------------- http://www.newd.demon.co.uk
> --------------------------------------------------------------------------
> -----



From rsowa at WizjaTV.pl  Mon Jan 11 11:26:22 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 11 Jan 1999 11:26:22 +0100
Subject: ODP: Digital DIY synths and DSP stuff
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D687A@demon>

find few compiled comments:

What kind of 16-bit converters?
AD1877, AD1859, AD1851 from Analog Devices
Sound Quality - 1851 low noise, 1859 low distortion
1877 - you ned no better ADC
unles you make heavy in $$$ digital mixing console

10-bit DAC PIC-based envelope
Yeah I think it would be enough, but with 10-bits you have to
use double precision calculations. Maybe no problem for C
but I use assembler only. (I have no C!)
Then we get to the point when analog ADSR becomes better option.
Personally I'd use digital envelopes only in all-digital synth

Bit resolution in floating point
Maybe someone could make some experiments and tell us all
if it is really heard.
And if SHARC's MAC result is stored in 40-bit float does it really
suffer from low headroom?

AN1x tweek
I ment playing with this as it is. No mods. Kinda minimalist for a DIYer
but if you asked me what I would do with spare 1k$...
And Ben, if you have AN1x, please open it and make some pictures too.

Roman






From Colin.Fraser at scottishpower.plc.uk  Mon Jan 11 11:55:56 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 11 Jan 1999 10:55:56 -0000
Subject: Simple sample playback using EPROMs
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2A0@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Budweiser [FTS] [mailto:budweiser at ozemail.com.au]
> Sent: 09 January 1999 15:14
> To: Quint; Sean Costello; synth-diy at mailhost.bpa.nl
> Subject: Simple sample playback using EPROMs
> 
> 
> I was think about making a simple sample play back module that used
> EPROMs, specifically for storing a 909 hihat and cymbol 
> samples, complete
> with the pitch control like the 909. I take it decay can be 
> easily made
> using
> VCAs on the outputs together with an EG....
> 
> Does anyone have schematics on the web somewhere?
> Obviously i'm going to need some sort of microcontroller,and i
> assume this sort of technology has been used in all kinds of
> machines over the years like the drumtracks, 707 909 etc..

It's not so complicated to need a microcontroller.
I have built all the 909 sound generator circuits myself, and have a put a
bit of info about the sample playback sounds on my extremely minimal web
site at http://www.octavo.demon.co.uk/colinf/home.htm including wav files of
the sounds generated from the original 909 rom data.

I will be adding more to this page soon, so I will scan in the 909 cymbal
schematics if I can't find them somewhere else.
Also to come will be very simple tune mods for the 909 bass drum and hihats.

Colin f



From Colin.Fraser at scottishpower.plc.uk  Mon Jan 11 12:44:40 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 11 Jan 1999 11:44:40 -0000
Subject: Digital DIY synths and DSP stuff
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2A2@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Roman Sowa [mailto:rsowa at WizjaTV.pl]
> Sent: 11 January 1999 10:26
> To: synth-diy at mailhost.bpa.nl
> Subject: ODP: Digital DIY synths and DSP stuff
> 
> 
> 10-bit DAC PIC-based envelope
> Yeah I think it would be enough, but with 10-bits you have to
> use double precision calculations. Maybe no problem for C
> but I use assembler only. (I have no C!)
> Then we get to the point when analog ADSR becomes better option.
> Personally I'd use digital envelopes only in all-digital synth

I wouldn't use a PIC to generate an ADSR envelope as this is easy enough
with an analogue circuit (no point using a sledgehammer to crack a nut).

I've been considering using a PIC as the basis for a more complicated
'transient sequencer'.
This would be an slew limiter with rate, target and slope (log-lin-exp)
controls, driven by a PIC via a DAC, with a window comparator to tell the
PIC when the target level is reached. 
It would need an interface to allow input of the parameters for generation
of complex n-stage envelopes, with options for gate control, repeating
cycles etc. The number of stages would only be limited by the memory
capacity of the PIC, but a serial eeprom on an I2C connection could provide
greater, non-volatile storage of parameters.
The interface would consist of rotary encoders for rate, target and slope,
with a numeric readout of the stage number, and the values for the current
stage.

Unfortunately, this idea is at the end of a long list of projects waiting
for the day when my girlfriend is rich enough for me to retire ;-)


Colin f





From wils0450 at itlabs.umn.edu  Mon Jan 11 14:42:34 1999
From: wils0450 at itlabs.umn.edu (Claire F.)
Date: Mon, 11 Jan 1999 07:42:34 -0600 (CST)
Subject: dayjobs
Message-ID: <Pine.GSO.4.05.9901110725130.4544-100000@urchin.itlabs.umn.edu>


I guess I'm a Rock Star. No kidding :) !!! 

I also produce visuals, compete in snowboarding on the amateur level
(easier to win :), produce a couple of different local acts, attend
university (got to fill up that free time), and occasionally participate
on dance and electronic oriented performance art. I also do social work
for AIDS patients and Native American children on the weekends (the AIDS
gig is inly once a month though...) I also seeem to get roped in to
touring once in a while, but not often.

(I was going to avoid doing this, but since my box was flooded with "day
job" messages - oh what the hell...)

			 The Family Werks presents...
                          Performing live at "Love"
		Valentine's day weekend in Minneapolis, MN USA
             ****Sonic Boom of Love featuring Clarissa Fragile*****
	       (also Boo WIlliams and some other big-name chumps)





From martin.czech at intermetall.de  Mon Jan 11 14:52:31 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 11 Jan 1999 14:52:31 +0100 (MET)
Subject: Website help needed! Looking for schematics links
Message-ID: <199901111352.OAA25987@window.intermetall.de>

>  am attempting to write a comprehensive listing of all the 
> schematics and manuals that are readily available on the web. A 
> first attempt can be found on http://www.bart.nl/~brun/index.htm, 
> go to the Schematics-DIY section of the site. It's meant to help 
> finding the right documentation for analog synths. As for me, I 
> always have to spend hours on the web before I find the scanned 
> schematic I need, if there is any. 
> 
> Your input is appreciated and needed! I will list all links to scanned 
> or 'webbed' manuals, viewable or downloadable schematics and 
> repair-FAQs concerning commercial analog synthesizers. Please 
> mail me your suggestions, and include a short description of the 
> synths that are covered. Of course I'll only link to the sites, to avoid 
> bandwith theft and to give full credit to the owners.
> 

Scanning all the 600 mails today (returned from vacation!), I found
out that there are severall attempts to collect and archive synth diy
data. I've started something similar in 98.

As you might know, mainly the mail traffic, ie. ascii data. But also
links.

Perhaps it would be better to do something together, instead of each
one inventing the wheel again and again?

Any comments, proposals ?

m.c.

see: http://www.geocities.com/SoHo/Museum/4459/grey_pages/grypag_index.html
see: http://www.geocities.com/SoHo/Museum/4459




From Chris.List at sc.siemens.com  Mon Jan 11 15:46:49 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 11 Jan 1999 09:46:49 -0500
Subject: dayjobs
Message-ID: <81A062BC5305D111A9D700805F06596801836C53@maildepo.sc.siemens.com>

> -----Original Message-----
> From:	Claire F. [SMTP:wils0450 at itlabs.umn.edu]
> (I was going to avoid doing this, but since my box was flooded with
> "day
> job" messages - oh what the hell...)
> 
	...me to.

	30 years old. Been programming in one language or another since
I was about 13. Comp. Sci. degree from Rutgers Univ. Had a couple of big
corporate IT development jobs and started my own consulting company
about a year ago - my one and only client being Siemens Corp. here in
NYC. My main job (for each company) since I got out of school has been
customizing J.D.Edwards (integrated business software, like SAP). It's
RPG programming on AS/400's and it's mighty boring compared to windows
and GUI stuff, but (IMHO) for business apps it's a lot easier, more
reliable, faster to develop, easier to troubleshoot, and easier to
upgrade than the client/server stuff (green-screen terminals are the
original "thin client"!). I've also done (and do) work in Oracle,
Powerbuilder, VB, Java, and C++.

	Started doing diy about 2 1/2 (or is it 3?) years ago, and
originally got into building electronics kits as a kid thanks to my dad
who was an EE (he's retired now).

	- Chris



From wils0450 at itlabs.umn.edu  Mon Jan 11 15:57:26 1999
From: wils0450 at itlabs.umn.edu (Claire F.)
Date: Mon, 11 Jan 1999 08:57:26 -0600 (CST)
Subject: Website help needed! Looking for schematics links
In-Reply-To: <199901111352.OAA25987@window.intermetall.de>
Message-ID: <Pine.GSO.4.05.9901110856480.4615-100000@urchin.itlabs.umn.edu>

A good idea...I have 50 megs of space availablle for such a project. :)


			 The Family Werks presents...
                          Performing live at "Love"
		Valentine's day weekend in Minneapolis, MN USA
             ****Sonic Boom of Love featuring Clarissa Fragile*****
	       (also Boo WIlliams and some other big-name chumps)





From sdcurtin at lucent.com  Mon Jan 11 16:08:48 1999
From: sdcurtin at lucent.com (Curtin, Steven D (Steven))
Date: Mon, 11 Jan 1999 10:08:48 -0500
Subject: day job...
Message-ID: <2E12619580C0D1118C6400805F9F4C9501BE5863@nj7460exch001u.ho.lucent.com>

I'm an applications engineer and project manager for a satellite radio
project here at Lucent.  This is a lot more fun than the last project I did
here which was Wave drivers for PC audio.  Prior to this I was in the Music
Industry for ten years after building my first analog synth ten years
before, eventually working at Ensoniq in their R&D department.  I went to
Lucent and more mainstream communications work because I got tired of being
laid off every two years working on something to make the perfect piano
sound.  Now I can be as "weird as I wanna be" with my weekend basement
experiments (see the web page for more info).  I do feel fortunate having a
job that grew out of my hobby in music and electronics, and my "day job" and
weekend fun continue to reinforce and compliment each other.  I would
encourage someone who wants to work on making musical instruments to go for
it, it was great fun for a while.

Steve C

-----------------------------------------------------------------
Steven Curtin  
Lucent Technologies Microelectronics
ph: (732)957-2996   fax: (732)957-6878
http://www.emf.org/subscribers/curtin/
sdcurtin at lucent.com
-----------------------------------------------------------------





From alexandr at irit.fr  Mon Jan 11 16:10:15 1999
From: alexandr at irit.fr (Karl ALEXANDRE)
Date: Mon, 11 Jan 1999 16:10:15 +0100
Subject: PCB layout software
References: <TFSGZWEU@idg.se>
Message-ID: <369A1457.2BE43406@irit.fr>

jorgen.bergfors at idg.se wrote:
> 
> I use Corel Draw both for PCBs and schematics. It is of course completely manual, but the automatic routing programs won't give you optimised results anyway. I have found that I can do quite a bit more compact boards with fewer wire links than the automatic programs. It is actually rather fun. A bit like laying a puzzle. Another big advantage is that you don't have to learn another program. A general drawing program can be used to so many other things. I design and print my front panel layouts with it too.
> 
> /Jorgen

	Well, why don't you use a dedicated software ? You can still use a
manual routing, but you have back-annotation, electrical
	rule check, etc... that way, if you have a correct schematic, you're
sure to have a correct pcb (electricaly speaking).

	Karl.



From martin.czech at intermetall.de  Mon Jan 11 16:30:27 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 11 Jan 1999 16:30:27 +0100 (MET)
Subject: gnuplot
Message-ID: <199901111530.QAA26333@window.intermetall.de>

gnuplot is a very nice tool for visualising data and formula etc.
I don't need to explain why some thing like this is very usefull for 
diy, ok ?

And it's free. Does anybody know if there is a windooze version ?

I have checked http://www.cs.dartmouth.edu/gnuplot_info.html
but there's only a dos version in protected mode, I fear.

Is there anything else free and comparable ?

m.c.




From thudson at cygnus.com  Mon Jan 11 16:34:57 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Mon, 11 Jan 1999 10:34:57 -0500
Subject: ODP: Day Jobs!! And deadly behaviour!
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6867@demon> <36962DC0.7B335EE8@cygnus.com> <3696E4B3.4C7D@swipnet.se>
Message-ID: <369A1A21.9B2CF787@cygnus.com>

BJ wrote:
> Well, seriously speaking this is some thing you really should avoid
> because most solder contaions led (Heavy Mettal)
> This soldering smoke will instantly go upp your nose and plugg your
> nose holes full with Heavy Metal!(guitar music).
>
I could blame guitar music (and that weird electronic noise)
for causing far worse substances to be ingested. Now, did
I like these substances because of electronic music, or did
these substances cause me to like electronic music?

> Have a look at "Ozzy Osborne" and you will see why its
> dangerous to solder and to inhale the fumes!!
Well, I turned 40 today, hopefully the years don't show
quite as much wear (though he has more hair than I).

Thomas, still suprised he made this far...



From urekar.m at EUnet.yu  Mon Jan 11 16:39:16 1999
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Mon, 11 Jan 1999 16:39:16 +0100
Subject: Simple sample playback using EPROMs
References: <BA865FF10473D211BC6F00805F0D830702D2A0@catsprntp01.cat.scottishpower.plc.uk>
Message-ID: <369A1B24.178D@eunet.yu>

> It's not so complicated to need a microcontroller.
> I have built all the 909 sound generator circuits myself, and have a put a
> bit of info about the sample playback sounds on my extremely minimal web
> site at http://www.octavo.demon.co.uk/colinf/home.htm including wav files of
> the sounds generated from the original 909 rom data.
> 
> I will be adding more to this page soon, so I will scan in the 909 cymbal
> schematics if I can't find them somewhere else.
> Also to come will be very simple tune mods for the 909 bass drum and hihats.


There are complete schematics for 909 at 

http://hardware.freepage.de/raf909/



marjan



From brun at bart.nl  Mon Jan 11 16:42:18 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Mon, 11 Jan 1999 16:42:18 +0100
Subject: dayjobs
In-Reply-To: <Pine.GSO.4.05.9901110725130.4544-100000@urchin.itlabs.umn.edu>
Message-ID: <199901111543.QAA16139@smtp2.xs4all.nl>

I think it's time for a new thread now.

Nightjobs anyone?  :-)



-> Brun, met een dakje op de u.

Nu aan het knutselen op http://www.bart.nl/~brun/index.htm



From oakley at techrepairs.freeserve.co.uk  Mon Jan 11 17:53:36 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Mon, 11 Jan 1999 16:53:36 -0000
Subject: Moog Bp filter!
Message-ID: <002501be3d82$f1230700$d438883e@default>

It was me. Take diff taps from the top and bottom caps and subtract
them. All you need is one quad op-amp.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html


-----Original Message-----
From: BJ <zzynt at swipnet.se>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Sunday, 10th January, 1999 2:51 AM
Subject: Moog Bp filter!


Will the gentleman who told us about
that he had made a BP filter out of a
Moog ladder please stand up!!

BJ





From oakley at techrepairs.freeserve.co.uk  Mon Jan 11 17:57:07 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Mon, 11 Jan 1999 16:57:07 -0000
Subject: day jobs
Message-ID: <002b01be3d83$6db45ee0$d438883e@default>

I am a househusband now. But I also fix guitar amps, keyboards etc for a
couple days a week for a bit of extra money.

Before that I was a teacher. And before that I designed Soundcraft
mixers.

Variety is the spice of life.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From hhelland at usa.net  Mon Jan 11 18:41:09 1999
From: hhelland at usa.net (Hallgeir Helland)
Date: Mon, 11 Jan 1999 18:41:09 +0100
Subject: Oberheim Xpander
Message-ID: <369A37B5.CDD857A1@usa.net>

Hullo,

Does anyone know if the schematics for the Xpander
is available on the Web anywhere...? I'm only interested
in the technology, I'm not gonna repair one or anything.

Thanx-a-lot,
Hallgeir


BTW thanks for the PCB software tips! I'll try the Eagle thing. :-)



From dslater at ix.netcom.com  Mon Jan 11 18:52:47 1999
From: dslater at ix.netcom.com (Dan Slater)
Date: Mon, 11 Jan 1999 09:52:47 -0800
Subject: day job...
References: <009101be3b89$154ed9c0$a0d26ccb@ppp.ozemail.com.au> <36983001.C19@mr.net>
Message-ID: <369A3A6F.93A6498F@ix.netcom.com>

Hi everyone;

    I currently work as an aerospace engineer in the areas of near-field
antenna measurements, launch vehicle avionics and electrooptical systems.
Web site is www.nearfield.com. Previously I worked in the entertainment
industry as a designer of special effects camera systems and laser light
show projectors.

    My current musical interests are toward the far fringes of electronic
music. I use Moog, Buchla, EMS and homebuilt equipment for both abstract
sound and visual synthesis. The synthesizers are augmented by various pieces
of aerospace surplus equipment including analog computers, telemetry
equipment, flight simulation hardware, etc.

Dan Slater





From rsowa at WizjaTV.pl  Mon Jan 11 18:58:41 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Mon, 11 Jan 1999 18:58:41 +0100
Subject: my ssm2164 quad VCO again
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6880@demon>

Hi all,

I have finally finished some pictures to put it on the web.
(meanwhile I found some errors in it)
I'm talking about my fresh, just finished quad VCO using
SSM2164 quad VCA chip.
To be even more strange, when I needed VCA, I didn't use SSM.

There are also some other stuff, and will be more
So here is the question:
I was thinkig that it would be cool if I wrote a little segment
for each circuit called "How Does It Work"
Do you think it is a good idea, or just a waste of space?
Is my style completely not understandable?
For this VCO there isn't much to write about, but others got more.

Anyway I'd be thankful for any comments about this website.
BTW I'm not so good at this as some of you are, so don't expect
to find any Java, frames, cool graphics etc.
Just plain text, and schemos

Ah, the URL!
here it is: http://www.multimania.com/romcio

Roman



From james at newd.demon.co.uk  Mon Jan 11 20:47:58 1999
From: james at newd.demon.co.uk (James Jackson)
Date: Mon, 11 Jan 1999 19:47:58 +0000
Subject: ODP: Filters
Message-ID: <1.5.4.32.19990111194758.00679144@pop3.demon.co.uk>

At 10:54 11/01/99 +0100, you wrote:
>Hi,
>good luck on this project...
>It's nice as soon as you'll manage to do it all
>
>Could you specify what you mean by Fourier Transform based filters?

Yes, I'll try, but I havn't learnt much about them yet. It would seem
through feedback from the list, that fourier transforms are not the best way
to do filtering on DSPs, but I'll try to explain anyway. Fourier transforms
allow you to extract the amplitude and other usefull stuff of any given
frequency when provided with a spectrum of audio (Or more usually, RF) data.
You can use this information to make any type of filter you want.

This may well be wrong, so mail the list if it is!

James Jackson.
-------------------------------------------------------------------------------
James Jackson - New Era Web Designs
          |
          ------------------- james at newd.demon.co.uk
Sales ------------------- sales at newd.demon.co.uk
Information ------------ info at newd.demon.co.uk

Website ---------------- http://www.newd.demon.co.uk
-------------------------------------------------------------------------------




From ka4hjh at gte.net  Mon Jan 11 21:02:33 1999
From: ka4hjh at gte.net (KA4HJH)
Date: Mon, 11 Jan 1999 15:02:33 -0500
Subject: PCB layout software
In-Reply-To: <Pine.GSO.3.96.990111012231.14972E-100000@general1.asu.edu>
References: <3698D544.1BD1BF0C@globaleyes.net>
Message-ID: <v04011700b2c0090f7d28@[208.255.152.16]>

>Rob wrote:
>> EAGLE PCB is the easiest and the best and has a full working demo
>> version.. wonderful software..
>
>and I inquire:
>
> is this for PC?  (it probably is, so on to my next q)  is there any PCB
>design software for Macs?
>-ben

Try this one:

http://www.swcp.com/~jchavez/osmond.html

Looks pretty decent. Almost Maclike.

Terry Bowman, KA4HJH
"The Mac Doctor"



From buchanan at qualcomm.com  Mon Jan 11 21:57:12 1999
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Mon, 11 Jan 1999 12:57:12 -0800
Subject: day jobs
In-Reply-To: <199901111543.QAA16139@smtp2.xs4all.nl>
References: <Pine.GSO.4.05.9901110725130.4544-100000@urchin.itlabs.umn.edu>
Message-ID: <3.0.3.32.19990111125712.016b3100@mage.qualcomm.com>

Hi all,

First off, three cheers to the 14 year old who started this thread - it's
been interesting to see what everybody else does + I'm stoked for anyone as
young as that and has rescource as vast as this list! (I didn't have anyone
to talk to about this stuff when I was 14).

I'm an RF Engineering Technician at Qualcomm in San Diego.  I work on phone
designs coming up with mods, tests, some minor design, and lots of
soldering - the tiny 0402 stuff you solder under a micrsocope.  It's a
great job!  I never worked above 100KHz before I came here and now I'm Zen
with 2GHz!  You know RF people refer to the audio band as DC?  I still get
kinda miffed by it....  ;-)

One cool thing is I've become sort of a sythnthesizer guru around here
which is an interesting parellel to my music synth stuff.... except these
synths run at 1.9GHz.  Working with RF makes you really appreciate how
straight forward life is below 1MHz!

C-ya,

Buck



From brun at bart.nl  Mon Jan 11 22:24:08 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Mon, 11 Jan 1999 22:24:08 +0100
Subject: Website help needed! Looking for schematics links
In-Reply-To: <Pine.GSO.4.05.9901110856480.4615-100000@urchin.itlabs.umn.edu>
References: <199901111352.OAA25987@window.intermetall.de>
Message-ID: <199901112129.WAA05097@Njord.bart.nl>

A good idea...I have 50 megs of space availablle for such a project. :)


Might come in handy... I'll give you a mail when I run out of my 
10... which might me sooner than I think.




--> Brun, met een dakje op de u.

Nu ook op http://www.bart.nl/~brun/index.htm



From buchi at dci.de  Mon Jan 11 23:17:45 1999
From: buchi at dci.de (Michael Buchstaller)
Date: Mon, 11 Jan 1999 22:17:45 GMT
Subject: PCB layout software
In-Reply-To: <C35556591D34D111BB5600805F1961B90BBEAF7A@RED-MSG-47>
References: <C35556591D34D111BB5600805F1961B90BBEAF7A@RED-MSG-47>
Message-ID: <369b7877.10177746@mail.dci.de>

On Sun, 10 Jan 1999 16:01:49 -0800, you wrote:

>I just spent a lot of time going over several packages and Eagle was the one
>for me too...  EdWin is a close second but it seems to be more oriented
>towards large group efforts.
>
>MicroCode CircuitMaker and TraxMaker are cute but don't really have the full
>package.  They tout a built-in analog simulation and Spice capability but
>they only have +10 and +5 voltages, no +15 and NO -15!!!  Analog my
>patootie!  The manual states that these can be built but I don't see why I
>should have to build something as basic as this...
>
>Ivex is good but I liked Eagle better.
>
>I had also bought a copy of Tango PCB and Schematic capture at an auction
>but I got the package minus the dongle.  I called the company, told them the
>situation, told them that I had the original manuals, the original bill of
>sale to the parent company, the original disks and my bill of sale from the
>auctioneer.  I just needed the dongle and the older version of the software
>would be fine for my needs.  
>
>They told me that I had to upgrade to the current version to get a new
>dongle and that was about $1,400  -  I will not ever consider dealing with
>that company again...
>
>-----Original Message-----
>From: Karl ALEXANDRE [mailto:alexandr at irit.fr]
>Sent: Sunday, January 10, 1999 2:25 PM
>To: synth-diy at mailhost.bpa.nl
>Subject: Re: PCB layout software
>
>
>> EAGLE PCB is the easiest and the best and has a full working demo
>> version.. wonderful software..
>> Rob
>
>	I agree, it's very intuitive and easy to lurn. It takes me
>	3 minutes to add an IC which is not in the libraries...
>	Unless you don't use the auto-router, it is perfect. This is
>	the one for homebrew projects.
>
>
>
>	Karl.


-Michael Buchstaller



From eduni at ucsd.edu  Tue Jan 12 00:23:25 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Mon, 11 Jan 1999 15:23:25 -0800 (PST)
Subject: day jobs
Message-ID: <199901112323.PAA06844@smtp.ucsd.edu>

At 12:57 PM 1/11/99 -0800, you wrote:
>Working with RF makes you really appreciate how
>straight forward life is below 1MHz!

-AMEN!!

-Ethan




From ben at stuyts.nl  Tue Jan 12 00:37:26 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue, 12 Jan 99 00:37:26 +0100
Subject: Digital DIY synths and DSP stuff... and drums
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D687A@demon>
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D687A@demon>
Message-ID: <199901112337.AAA02091@daneel.stuyts.nl>

On Mon, 11 Jan 1999, Roman Sowa wrote:

> What kind of 16-bit converters?
> AD1877, AD1859, AD1851 from Analog Devices
> Sound Quality - 1851 low noise, 1859 low distortion
> 1877 - you ned no better ADC
> unles you make heavy in $$$ digital mixing console

Aha, so none of the combined a/d and d/a's are any good?
I see some of them are single +5V supply. Very convenient!

> AN1x tweek
> I ment playing with this as it is. No mods. Kinda minimalist for a DIYer
> but if you asked me what I would do with spare 1k$...

Well, next thing I want to have is some sort of drum box. Nothing fancy, but  
something with lots of rhythms/instruments would be nice. The Yamaha RS8 or  
RS20 look nice, and aren't too expensive. Especially the RS8 look good value  
for money. Again, probably as digital as it gets from power supply to  
output...

(Insert wobbly vertical lines here.)
Long time ago I built a full analog drum computer. It was published in  
Elektuur (of Formant fame), somewhere in the early 1970's. It had a tip-touch  
panel to select the various drum patterns for each instrument separately. I  
never got the front panel to work well, so I finally replaced it with a ton of  
mechanical switches. The drums were based on a gyrator circuit. Quite complex  
as I remember, all discrete's. I think there were 200+ transistors in that  
thing. Only the sequencer had some 7400 stuff in it. The cymbals always used  
to sound more like a gunshot... In the end, the sequencer died too, so I  
connected it the instrument pcb's (yes, each instrument had a separate pcb,  
the snare even had two) to the parallel port of a Comodore Pet 2001. So that's  
how old I am. B-) I still have a recording somewhere where I used it  
(softly!) in a blues rhythm for a song I did with some classroom mates in  
highschool. I don't think I have it anymore. Haven't seen it in 10+ years. It  
probably got lost during moving.

Is there anybody else out there who built this thing? I can't recall the  
exact name. Something like Elekdrum? Elektrom?

> And Ben, if you have AN1x, please open it and make some pictures too.

Good idea, I will put some pictures up soon. (Will do the Zoom 1204 too.)

Best regards,
Ben



From edusilva at bahianet.com.br  Tue Jan 12 00:49:57 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Mon, 11 Jan 1999 21:49:57 -0200
Subject: SH09 service manual
Message-ID: <199901121210.KAA07823@postman.bahianet.com.br>

Thanks for all the replies! My SH is happy now!  :)

Edu
 (hearing his SH09 bleepin' and blop?n' again)



From lfutten at readysoft.es  Tue Jan 12 01:03:03 1999
From: lfutten at readysoft.es (lfutten at readysoft.es)
Date: Tue, 12 Jan 1999 00:03:03 +0000
Subject: day job...
In-Reply-To: <369A3A6F.93A6498F@ix.netcom.com>
Message-ID: <199901112317.AAA21962@www.readysoft.es>

OK, as everybody seems to talk about our day job, here I am...

Being a Computer Science engineer, working in the IT field for about 
9 years, now I'm in a career transition into the music field.
I used to attend to a lot of recording engineering workshops and 
courses as a hobby, but now I want to live from this.
I'm also a singer, I worked for 12 years as a weekend DJ, play 
percussions, sing oldies in a band every tuesday night, sometimes I 
collaborate in many churchs' chorals, I'm setting up a more decent 
home-studio right now... 
I'm learning to play violin in my spare time, and as I live in a 
small town of southern spain, is not difficult to find me on the 
beach on sundays mornings.... My sport is to swimm.
As I'm still in 'transition', I can't say I can earn my life only by 
my music skills yet, so I'm still working part time with computers.

And I guess that's all.

Luz Futten
on the way to be a rock star ;) hehe..

???



From eduni at ucsd.edu  Tue Jan 12 01:17:09 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Mon, 11 Jan 1999 16:17:09 -0800 (PST)
Subject: ODP: Filters
Message-ID: <199901120017.QAA13988@smtp.ucsd.edu>


>Yes, I'll try, but I havn't learnt much about them yet. It would seem
>through feedback from the list, that fourier transforms are not the best way
>to do filtering on DSPs, but I'll try to explain anyway. Fourier transforms
>allow you to extract the amplitude and other usefull stuff of any given
>frequency when provided with a spectrum of audio (Or more usually, RF) data.
>You can use this information to make any type of filter you want.
>
>This may well be wrong, so mail the list if it is!

-i wouldn't say outright "wrong", but perhaps it could be more correct.. the
Fourier Transform allows you to look at amplitude vs. time data and
calculate amplitude vs. frequency data as well as phase vs. frequency data.
Once you are into the frequency domain, you can impose arbitrary filter
contours onto the data and then use an inverse Fourier Transform to get back
to the time domain.  

In digression: this can be done in the time domain as well.  The "filter
contour" above is the frequency response of the filter.  The frequency
response of a (linear, time-invariant) system is the Fourier Transform of
its impulse response.  The impulse response is defined as what happens at
the output of a system when you feed in an "impulse" -a spike of infinite
amplitude and zero duration with an integral of one.  (this is where the
terms FIR- Finite Impulse Response and IIR- Infinite Impulse Response come
in).  You can take the impulse response and the input signal and feed them
into the Convolution Integral to get the output.  however, directly
evaluating the Convolution Integral is, at best, a very computationally
expensive process and as it turns out (should be apparent from this
digression) it is equivalent to taking the Fourier Transform of both data
and multiplying them together and then taking the inverse Fourier Transform
of the result.  This is usually significantly faster and is how the
Convolution Intgeral is often calculated.  

anyway, back to the point.. using an FFT based filter, while very cool, is
probably overkill for doing analog synth modelling (that is what you were
wanting to do, no?).  Making an FFT filter do modulable resonance and cutoff
in real time (while really cool) would be a severe pain in the ass,
especially compared to using "FIR" and "IIR" methods, which will probably be
just as good for doing analog-synth style filtering (anyone have any
opinions here?).  

On the other hand, another approach might be to not use an FFT at all; just
start in the frequency domain and build your oscillators as collections of
harmonics with various amplitudes and phases (i've written a windows
softsynth with labview that does this, incidentally.. not in real time
though.  if anyone would like to play with it, let me know).  The fourier
series for common shapes like triangles, sawtooths, pulses and (of course)
sines are well known and easy to plug into a frequency-domain array.  then
you just multiply the thing by a filter contour and iFFT it.  however, at
this point we are talking about building a K5000 (additive synth) instead of
an analog-style one.  this also requires you to become familiar with the
frequency-scaling algorithms to keep the harmonics, well, harmonic.. but
controlling aliasing becomes somewhat trivial.  also (as mentioned above),
there is the problem of getting the filter contour to interpolate properly
between different cutoffs and resonances.. i've never tried it, but i
imagine it would require some pretty tricky coding to do in real-time..
another thing about the fourier transforms in general is that they output
complex numbers, which complicates all the calculations (anyone familiar
with the SHARC instruction set care to comment?)

all depends on what you want to do i suppose.. i hope this was some help.. 

incidentally, i have a big design project coming up in the next couple of
years for my degree.  what i've been thinking of doing is sort of along
these lines.. I'm calling it a convolution-synth for lack of a better term;
the idea is to start in the frequency domain as described above.  what i'd
like to do is go and get the impulse responses of a whole bunch of filters,
instruments, drums, reverb units, etc. and then transform all of them and
keep them as a bank of filter contours.  i'd also like to construct  models
of (if not directly record) common real-world "impulses" (plucking violin
strings, blowing into a tube, hitting something with a stick, etc.).  these
would then be used to initially fill the frequency-domain array (as well as
some algorithmically generated ones like sines, pulses, various noise,
etc.).  then this would be multiplied by whatever frequency response (or
responses if there's time) you have decided to use and iFFT'd.  of course
the magic would come in with interpolating between different shapes and
inputs with different controllers.  also, ideally, the filter responses
would be "multi-sampled" in different registers, etc.  another nice bonus
would be an external audio input tot he thing.. we'll see.. This whole thing
of course would be fed into adsr's etc. once back into the time-domain.  of
course doing this in real-time is going to be the really hard part.. 

hope that made sense..

anyone have more ideas?
Ethan




From edusilva at bahianet.com.br  Tue Jan 12 01:30:37 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Mon, 11 Jan 1999 22:30:37 -0200
Subject: PCB layout software
Message-ID: <199901121210.KAA07826@postman.bahianet.com.br>

Let's see:

	- I'm using TangoPRO eval version (windows, full-working), but someone
told me the DOS version is better. Why didn't he sent me a copy?
	- EasyTraks (free) doesn't have a driver for my Epson SC 600, so I put it
aside.
	- There's a copy of Ultimate PCB (DOS) in my HD, but I haven't tryed it
yet.
	- Winboard/Windraft are nice, but the demo versions are limited to 100
pins, not enough for me. (And not enough money to register my copy...)
	- Corel Draw doesn't seems to have any advantage over a real PCB layout
soft, but I tried it once (don't like automatic routing, too).

Think it's time to download Eagle PCB!


_____________________
Edu Silva - ES2 Audio
Salvador-Bahia-Brasil




From corley.brigman at intel.com  Tue Jan 12 01:58:00 1999
From: corley.brigman at intel.com (Brigman, Corley)
Date: Mon, 11 Jan 1999 16:58:00 -0800
Subject: ODP: Filters
Message-ID: <199901120109.RAA11234@hebe.or.intel.com>

>especially compared to using "FIR" and "IIR" methods, which will probably
be
>just as good for doing analog-synth style filtering (anyone have any
>opinions here?).

ok, i don't know a whole lot about filtering (some from a DSP class), and I 
answered this for the below instead, but: most real filters can be better 
approximated with IIR filters. the main difference between FIR filters and
IIR 
filters is that the FIR filter uses a finite number of data points and the
IIR 
filter an infinte number of data points. infinite, you say? how's that?
well, 
FIR filters take as input only samples in the input data stream; an IIR
filter 
also takes samples in the output data stream. which is to say, that if x is
the 
input stream, y is the output stream, and a is an array of constants:

FIR:
y[n] = a[n-k]x[n-k] + ... + a[n]x[n] + a[n+1]x[n+1] + ... + a[n+k]x[n+k]

where as:
IIR:
y[n] = a[n-k]x[n-k] + ... + a[n]x[n] + a[n+1]x[n+1] + ... + a[n+k]x[n+k] +
       b[n-k]y[n-k] + ... + b[n]y[n] + b[n+1]y[n+1] + ... + b[n+k]y[n+k]

Theoretically, k can be infinity, but practically of course it's not :)
Since 
the y[n] for the IIR is recursive, however, it kind of implicitly goes to 
infinity since even the simple:

y[n] = .9y[n-1] + x[n]

depends on EVERY previous data point back to -infinity. 

IIR filters usually require less terms and are much easier to implement 
realtime. At least, AFAIK - i've never actually done one :) I will 
eventually....

>(i've written a windows
>softsynth with labview that does this, incidentally.. not in real time
>though.  if anyone would like to play with it, let me know).  

i would! i built something similar (no filters yet though), except it really
was
additive i.e. no ifft. and definitely not real time. so there's no problem
with 
harmonics not becoming "harmonic". the filter contour just affects the gain
of 
each harmonic, so adding a filter becomes just a simple multiplication per 
harmonic. 

the main problem with the FFT-based implementation is, afaik, that each
"window"
of the FFT don't have a 1:1 correspondence to frequency. i.e.: at 44.1KHZ,
if 
you take a sample of 512 samples, then each sample corresponds to approx. 43
HZ 
(iirc) and I THINK it is linear?? can't remember for sure. increasing the
window
size helps, but for each band you are increasing/decreasing a frequency
RANGE 
and not a frequency per se - i guess this is why you have the "harmonic" 
problems? note that I'm not real familiar 
with the iFFT math (it's simpler than FFT math, right?) but doing it as
straight
sines can be very precise, allowing specific detuning, etc. (which is
included 
in the program I wrote) phase doesn't matter at this point, although I did 
include it :) also, given some memory it can be very fast. you can use a
kind of
"phase accumulator" (at least this is what I though you guys meant when you
were
first talking about it) where you divide 2pi by the number of samples per
cycle 
(yes, this can be a fraction) giving you the increment to phase, which is
then 
fed into a sine function (there are several ways to speed this up, i think,
one 
way is lookup tables, but there are many others - you can trade accuracy for

speed here if desired). one more multiplication per harmonic gives you
filter, 
just like the FFT version. i don't know if it's simpler or more complex, but

it's different.

a preview of the (dos) version of this program is at 
http://members.xoom.com/elev8. it's early and is a VERY simple additive
synth 
with no filters. i wrote it to send basic waveforms to my prophet 3000
sampler, 
which has nice cem3387 analog filters....

anyway, i plan to add modulations (envs, lfos, etc), a formant filter which
will
have several models that are mathematically pure as well as a user-definable

X-band graphic EQ. as well as other waveforms for the additive engine (this 
won't work for the formant filter, at the moment). the k5000 formant filter
is a
128-band graphic EQ. an FFT-based system might work better here, since
that's 
kind of what it is, for non-sinewave base waveform. but maybe an FFT-type 
analyzer might give me a good harmonic list here, which I could use to add 
together instead.. anyway this is heavy into additive. although they are
very 
related.

one more advantage of this is that I plan to have FM-style feedback loops 
available as well i.e. in addition to the envelopes for each harmonic, the 
harmonics themselves can be used as modulation sources, which could modulate

volume of other harmonics for instance or pitch (FM) of another harmonic.
i'm 
planning to allow phase mod too for those casio CZ-style patches :) anyway i

wrote the above program in a couple of days a few months ago, with not much 
progress since. time to get cracking again....

<design idea>

sounds very cool.

corley brigman
intel corp.
corley.brigman at intel.com

speaking for me, not for intel.



From bjbean at digizen.net  Tue Jan 12 02:02:21 1999
From: bjbean at digizen.net (Bernie Bean)
Date: Mon, 11 Jan 1999 20:02:21 -0500
Subject: Oberheim Schematic Needed
Message-ID: <3.0.32.19990111200214.00697620@mail.digizen.net>

Hello;

Does anyone out there have service manuals or schematics for Oberheim DMX and 
Xpander? Service in my area has become unavailable and while I don't have
time I am on my own.

Thank You
Bernie Bean



From zzynt at swipnet.se  Tue Jan 12 02:53:26 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 11 Jan 1999 17:53:26 -0800
Subject: dayjobs
References: <Pine.GSO.4.05.9901110725130.4544-100000@urchin.itlabs.umn.edu>
Message-ID: <369AAB16.2A68@swipnet.se>

Claire F. wrote:
> 
> I guess I'm a Rock Star. No kidding :) !!!
> 
> I also produce visuals, compete in snowboarding on the amateur level
> (easier to win :), produce a couple of different local acts, attend
> university (got to fill up that free time), and occasionally participate
> on dance and electronic oriented performance art. I also do social work
> for AIDS patients and Native American children on the weekends (the AIDS
> gig is inly once a month though...) I also seeem to get roped in to
> touring once in a while, but not often.
> 
> (I was going to avoid doing this, but since my box was flooded with "day
> job" messages - oh what the hell...)

Perhapps it is like this, the things you do as a "day job"
is infact the things all the rest of the diy list members
"actually" wishes to do, or at least dreams of to do!  :)

BJ
(just speculating some)



From eduni at ucsd.edu  Tue Jan 12 03:15:25 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Mon, 11 Jan 1999 18:15:25 -0800 (PST)
Subject: ODP: Filters
Message-ID: <199901120215.SAA24665@smtp.ucsd.edu>

>i would! i built something similar (no filters yet though), except it really
>was
>additive i.e. no ifft. and definitely not real time. so there's no problem
>with 
>harmonics not becoming "harmonic". the filter contour just affects the gain
>of 
>each harmonic, so adding a filter becomes just a simple multiplication per 
>harmonic. 

-the harmonic distortion i was referring to wasn't in the filter.. it
actually comes up more when you are trying to pitch-shift some signal with
an FFT.  if you just shift the whole spectrum up by a given amount the
harmonic relationships in the signal can get distorted.  e.g., say you have
some signal that is 100Hz + 200Hz.  now you FFT it and shift it by 50Hz.
now you have 150Hz and 250Hz; uh oh! so much for that second harmonic.. not
really a complicated problem, and if you are doing purely additive synthesis
(i.e., just filling a frequency-domain array from scratch), it's easy enough
to avoid, but i thought i'd mention it anyway.. 

>the main problem with the FFT-based implementation is, afaik, that each
>"window"
>of the FFT don't have a 1:1 correspondence to frequency. i.e.: at 44.1KHZ,
>if 
>you take a sample of 512 samples, then each sample corresponds to approx. 43
>HZ 
>(iirc) and I THINK it is linear?? can't remember for sure. increasing the
>window
>size helps, but for each band you are increasing/decreasing a frequency
>RANGE 
>and not a frequency per se - i guess this is why you have the "harmonic" 
>problems? 

-isn't it 86Hz per frequency-domain data point at 44.1KHz with 512 samples
(half of the frequencies being negative- meaning above the nyquist
frequency)?  and yeah, i think it is linear.  this also brings up the issue
of frequency resolution vs. time resolution.  you need bigger windows to get
better frequency accuracy, but in doing so you can only define the
frequencies over the period of the window.  i've seen the Heisenberg
Uncertainty Principle applied to this problem to show that delta t times
delta f is greater than or equal to the inverse of (i think) 4 pi.  this is
all to say that you can only define frequency exactly over infinite time and
as you approach instantaneity (smaller and smaller time intervals), your
frequency resolution goes to hell.  This all is a bummer for music
applications because of course we'd like our sounds to be very fluid and
dynamic, but this screws the accuracy of the frequencies in the transform..
there are some advanced and sneaky workarounds for this, but i'm not really
familiar with them.. anyone?

>note that I'm not real familiar 
>with the iFFT math (it's simpler than FFT math, right?) 

-i think that computationally it's very similar.. 

>but doing it as
>straight
>sines can be very precise, allowing specific detuning, etc. (which is
>included 
>in the program I wrote) phase doesn't matter at this point, although I did 
>include it :) also, given some memory it can be very fast. you can use a
>kind of
>"phase accumulator" (at least this is what I though you guys meant when you
>were
>first talking about it) where you divide 2pi by the number of samples per
>cycle 
>(yes, this can be a fraction) giving you the increment to phase, which is
>then 
>fed into a sine function (there are several ways to speed this up, i think,
>one 
>way is lookup tables, but there are many others - you can trade accuracy for
>
>speed here if desired). one more multiplication per harmonic gives you
>filter, 
>just like the FFT version. i don't know if it's simpler or more complex, but
>
>it's different.

-that's an interesting approach.. i'd speculate that this would be more
efficient for the case of smaller numbers of constituent frequencies, but
i'd think an ifft would be better for more complicated stuff.. you'd
acutally need more than one multiplication per harmonic for the filter; the
frequency response of the filter could be achieved this way, but with the
FFT method you are using an array of complex numbers that represents  both
the frequency and phase response of the filter in question (although if you
are looking to implement a perfectly phase-distortion-free filter, this
isn't a problem :])

>a preview of the (dos) version of this program is at 
>http://members.xoom.com/elev8. it's early and is a VERY simple additive
>synth 
>with no filters. i wrote it to send basic waveforms to my prophet 3000
>sampler, 
>which has nice cem3387 analog filters....
>
>anyway, i plan to add modulations (envs, lfos, etc), a formant filter which
>will
>have several models that are mathematically pure as well as a user-definable
>
>X-band graphic EQ. as well as other waveforms for the additive engine (this 
>won't work for the formant filter, at the moment). the k5000 formant filter
>is a
>128-band graphic EQ. an FFT-based system might work better here, since
>that's 
>kind of what it is, for non-sinewave base waveform. 

-uh-oh, we're dangerously close to wavelet analysis here :]  
and isn't the k5000's formant filter FFT-based (or rather iFFT; i'm not sure
the data has ever left the frequency domain at that point)? 

>but maybe an FFT-type 
>analyzer might give me a good harmonic list here, which I could use to add 
>together instead.. anyway this is heavy into additive. although they are
>very 
>related.

-you know, i like this idea.. i'm thinking that, from an oscillator point of
view, having arbitrary basis functions (perhaps even different functions for
a given harmonic?) would let you produce a wider variety of waveforms, and
then use an FFT-style filter after the fact (hey, the filter won't know you
cheated and didn't start with sines).  though at this point, i'm seriously
wondering if moving the whole thing into a Wavelet Transform based system
wouldn't work better to this end.. guess i'll have to go learn more about
them.. 

>one more advantage of this is that I plan to have FM-style feedback loops 
>available as well i.e. in addition to the envelopes for each harmonic, the 
>harmonics themselves can be used as modulation sources, which could modulate
>
>volume of other harmonics for instance or pitch (FM) of another harmonic.
>i'm 
>planning to allow phase mod too for those casio CZ-style patches :) 

-another good idea.




From costello at seanet.com  Tue Jan 12 03:18:55 1999
From: costello at seanet.com (Sean Costello)
Date: Mon, 11 Jan 1999 18:18:55 -0800
Subject: ODP: Filters
References: <199901120109.RAA11234@hebe.or.intel.com>
Message-ID: <369AB10F.3F285E5B@seanet.com>

Brigman, Corley wrote:

> the main problem with the FFT-based implementation is, afaik, that each
> "window"  of the FFT don't have a 1:1 correspondence to frequency. i.e.: at 
> 44.1KHZ, if  you take a sample of 512 samples, then each sample corresponds to 
> approx. 43 HZ (iirc) and I THINK it is linear?? can't remember for sure.
> increasing the window size helps, but for each band you are increasing/decreasing > a frequency RANGE and not a frequency per se - i guess this is why you have the 
> "harmonic" problems? 

OK, this is an area I am not too comfortable with yet, but I have done a
little reading. ("I'm not a doctor - but I watch a lot of TV.")  The
phase vocoder resolves this problem by tracking the phase of each
frequency bin in the FFT, and using the change in phase for each window
to determine the actual frequency.  A phase vocoder can analyse a sound,
and perfectly reconstitute the sound from the analysis material,
provided that no changes have been made in between analysis and
resynthesis.  Various other nifty techniques can be applied - for
example, SMS analysis (developed by Xavier Serra during his stint at
CCRMA) analyses a signal and breaks it down into sinusoids plus a
"residual" of filtered noise.  I think this is done by assuming that
components in the frequency bins that are slowly changing are the
sinusoidal components of the signal, while components that change
amplitude and phase rapidly are better described as "noise."

BTW, I am planning on taking some EE courses soon, so I should hopefully
know what the hell I am talking about soon.  The computer music course I
am taking is cool, but the teacher doesn't have time to get into the
technical nitty-gritty. He certainly knows how to do it (he developed
time strecting and phase vocoding opcodes for Csound), but the class has
to be tailored towards the music composition students.  Time to squeeze
into those EE classes.

Sean Costello

"I'm not a doctor - but I'm Charles Manson."



From theremin1 at worldnet.att.net  Tue Jan 12 03:50:27 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Mon, 11 Jan 1999 18:50:27 -0800
Subject: my ssm2164 quad VCO again
Message-ID: <009501be3dd6$500122e0$fb744e0c@hpcustomer>

Yeah!  Explanatory documentation is always a good companion 
for a schematic; it turns a design into a lesson.

-Art

-----Original Message-----
From: Roman Sowa <rsowa at WizjaTV.pl>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Monday, January 11, 1999 2:03 PM
Subject: my ssm2164 quad VCO again


>Hi all,
>
>I have finally finished some pictures to put it on the web.
>(meanwhile I found some errors in it)
>I'm talking about my fresh, just finished quad VCO using
>SSM2164 quad VCA chip.
>To be even more strange, when I needed VCA, I didn't use SSM.
>
>There are also some other stuff, and will be more
>So here is the question:
>I was thinkig that it would be cool if I wrote a little segment
>for each circuit called "How Does It Work"
>Do you think it is a good idea, or just a waste of space?
>Is my style completely not understandable?
>For this VCO there isn't much to write about, but others got more.
>
>Anyway I'd be thankful for any comments about this website.
>BTW I'm not so good at this as some of you are, so don't expect
>to find any Java, frames, cool graphics etc.
>Just plain text, and schemos
>
>Ah, the URL!
>here it is: http://www.multimania.com/romcio
>
>Roman




From theremin1 at worldnet.att.net  Tue Jan 12 04:07:53 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Mon, 11 Jan 1999 19:07:53 -0800
Subject: PCB layout software
Message-ID: <00b101be3dd8$bf99a3a0$fb744e0c@hpcustomer>

I use uSoft Paintbrush to bitmap my schematics.  (Just slightly more
sophisticated than a pencil and eraser!)

PCBs?  I wirewrap EVERYTHING, even my 8nS comparators and 25MHz HCMOS
circuits.  It works, if you're careful.  Nothing beats wirewrapping for a
quick turnaround, and it is relatively inexpensive.

Does anyone else on the list use wirewrapping???  How about a wood cutting
board with small finishing nails?  (That is, after all, where the term
"breadboard" came from!)

-Art in Thereminland


-----Original Message-----
From: Karl ALEXANDRE <alexandr at irit.fr>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Monday, January 11, 1999 8:06 AM
Subject: Re: PCB layout software


>jorgen.bergfors at idg.se wrote:
>>
>> I use Corel Draw both for PCBs and schematics. It is of course completely
manual, but the automatic routing programs won't give you optimised results
anyway. I have found that I can do quite a bit more compact boards with
fewer wire links than the automatic programs. It is actually rather fun. A
bit like laying a puzzle. Another big advantage is that you don't have to
learn another program. A general drawing program can be used to so many
other things. I design and print my front panel layouts with it too.
>>
>> /Jorgen
>
> Well, why don't you use a dedicated software ? You can still use a
>manual routing, but you have back-annotation, electrical
> rule check, etc... that way, if you have a correct schematic, you're
>sure to have a correct pcb (electricaly speaking).
>
> Karl.
>




From sidlar at norlink.net  Tue Jan 12 05:10:16 1999
From: sidlar at norlink.net (Frank Lemieux)
Date: Mon, 11 Jan 1999 23:10:16 -0500
Subject: day job...
In-Reply-To: <009101be3b89$154ed9c0$a0d26ccb@ppp.ozemail.com.au>
Message-ID: <3.0.2.32.19990111231016.007a2780@nomin.norlink.net>


I'm a first year college student studying Electronic Engineering with a
specialization in computer networking.  I've come to synthesis with a love
of surreality, and to diy from a love of electronics.  I like gear
optimized for performance, and a lot of what i do is repairing, modding, or
customizing my gear for myself.  I play keyboards in a black metal band,
and drums in a funk band...  slowly working towards electronicizing my kit.
 I'll get there, piece by piece...

I actually credit Synth-DIY for my decision to follow my inclination and go
into electronics.  I've learned so much here that I am now many many months
ahead in my studies.  Thank you, Synth-DIY! :)




From aschrock at cs.brandeis.edu  Tue Jan 12 05:30:48 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 11 Jan 1999 23:30:48 -0500 (EST)
Subject: web site annoucement
In-Reply-To: <369A3A6F.93A6498F@ix.netcom.com>
Message-ID: <Pine.SGI.3.95.990111153934.2324A-100000@pearl.cs.brandeis.edu>

Hey all..

I've been putting some work into my web site recently, and am fairly
pleased with the results. It has two sections right now: the Buchla
sampling CD page (which ultimately won't be released until the summer) and
the sh-101 modification page. The former has a few samples and is about
as done as it will be for a while (unless I add more samples) and the
latter is pretty unfinished, maybe 50% done. Several updates will occur
over the next few days, only a few steps are finished. Anyhow, take a
look, tell me what ya think of ANY part of the web page (buchla samples,
101 mod, whatever!), I'd appreciate it. 

The address is: www.cs.brandeis.edu/~aschrock/jnk, the "jnk" stands for my
pet project called "Jacks and Knobs". I figured it was better than another
company of the form "synth-noun".. :) 

Thanks all, 
Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From pinknoiz at pinknoiz.com  Tue Jan 12 06:15:53 1999
From: pinknoiz at pinknoiz.com (Bob Gonsalves)
Date: Mon, 11 Jan 1999 21:15:53 -0800
Subject: day job...
In-Reply-To: <Pine.SOL.3.96.990108183718.8497D-100000@muss.cis.McMaster.CA>
References: <199901082150.NAA11076@atari.saturn5.com>
Message-ID: <v04020a02b2c0897c4fa4@[207.21.142.185]>

At 6:38 PM -0500 1/8/99, Sen! wrote:
>I'm an occupational therapist by day.
>
>I specialize in augmentative communication and assistive technology.
>

My day job is somewhat related. For the past 8 years I've worked at a
startup company developing and then propagating a computer based device
used to help brain stroke survivors recover their use of language (in
conjunction with a specific treatment plan). I'm rewriting the current
iteration in Java.

I built my first PAiA kit around 1975 when I was an undergraduate student.
Over the years the time devoted to electronic music has varied greatly
(it's increased in the past year) but my interest in it has never wavered.

Bob Gonsalves, Research Director, Pink Noise Studios
Art*Technology*Politics  http://www.pinknoiz.com/




From qfulsom at usa.net  Tue Jan 12 07:31:26 1999
From: qfulsom at usa.net (Quint)
Date: Tue, 12 Jan 1999 00:31:26 -0600
Subject: web site annoucement
Message-ID: <000901be3df5$2f32e8e0$62fd5380@s8p8t9>

>The address is: www.cs.brandeis.edu/~aschrock/jnk, the "jnk" stands for my
>pet project called "Jacks and Knobs". 

You could be steppin on a lawsuit from russ meyers with that, ha ha.





From ullrich at vienna.at  Tue Jan 12 07:44:55 1999
From: ullrich at vienna.at (Peter Ullrich)
Date: Tue, 12 Jan 1999 07:44:55 +0100
Subject: Digital DIY synths?
Message-ID: <369AEF67.FBC64AB0@vienna.at>

I started programming a n analog synth emulator with the Analog Devices
EZKIT-Lite Board (ADSP2181). As my time is very limited I stopped at the
most difficult part: the filter.

This is what the software can do at the moment:

generate sawtooth and rectangle/pwm sounds
simple envelope generator
noise generator
sine modulator
vca-equivalent

So these are only the very first modules - not a synth at all!

If anyone is interested in the simple code I could thing of putting it
on my webpage...

If anyone programmed a VCF-like filter for these board I would be
interested in it!!!

Ciao
Peter
-- 

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/



From zzynt at swipnet.se  Tue Jan 12 07:45:53 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 11 Jan 1999 22:45:53 -0800
Subject: OSCar is up on the net!
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6880@demon>
Message-ID: <369AEFA1.5B5@swipnet.se>

OK people, the OSCar shematics is no on the net at:
http://home8.swipnet.se/~w-88660/schpcb.htm
(as usuall )

7 pages, including the latest midi retrofit for the
OSCar in a piggy back, orginal drawing is an A3 format
who i have scaled down to a A4 and the into a easily
handled PDF files.

I have compressed the files as much as possible without 
loosing the resolution, i hope.This is the original shemo
that Criss Hugget (Novaton) made by hand!!! Beware!!!.

The pages is betwen 39k to 87k in size.

BJ



From martin.czech at intermetall.de  Tue Jan 12 08:43:39 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 12 Jan 1999 08:43:39 +0100 (MET)
Subject: PCB layout software
Message-ID: <199901120743.IAA02523@window.intermetall.de>

> 	Well, why don't you use a dedicated software ? You can still use a
> manual routing, but you have back-annotation, electrical
> 	rule check, etc... that way, if you have a correct schematic, you're
> sure to have a correct pcb (electricaly speaking).
> 

Shure.

But one thing is also shure:

It takes a hell lot of time to set up the system.  You have to define
object bodys, schematic views, simulation code, pinouts and a footprint
for EVERY single type of component you use.  Most probably you have to
define a lot of resistor and capacitor types because of varying wire
length (instead using wire bridges you often use resistors with long
wires to get over some pcb trakcks, whenever possible etc.).

Most software packages I know have lots of 74LSXXX in their librarys,
and maybe a 741, but most of our analog stuff is not there.

Not to mention all the debugging afterwards, because of wrong defined
pinouts etc. etc. I do this all day long in my day job, every cell I
design gets a schematic body, simulation code (hand coded if necessary)
etc etc, and very often I get netlist problems at first, because I've
forgotten something, or mixed it up.

I estimated that setting up such a system with all the components you will ever use will take the time of 3-4 complete modules alltogether. 
I think that this is much to much for diy (but ok for professional use).

So Jorgen has some reason for hand layout.

Maybe I have just evaluated the wrong software package.
Then I would be greatfull for any hint to a package which doesn't have all
the disadvantages I've mentioned above.


m.c.




From varner at k-online.com  Tue Jan 12 09:34:37 1999
From: varner at k-online.com (Steve Varner)
Date: Tue, 12 Jan 1999 00:34:37 -0800
Subject: No PCB layout software! (plus Mac info)
References: <Pine.GSO.3.96.990111012231.14972E-100000@general1.asu.edu>
Message-ID: <369B0918.49DE660D@k-online.com>

Firstly, let me say that I don't use any layout software. Most analog
modules are pretty basic. I played around for days with some software and
got really frustrated. I just want to put a chip or two and a handful of
resistors and the odd transistor and capacitor on a small board (10x15cm,
4x6"). Most software has several layers, color, and a complex interface. I
can lay out a board from a simple schematic in much less time than I can
fiddling with software. I use Barry Klein's method. I lay out the standard
parts on 0.1 inch (2.5mm) engineering (graph) paper. Resistors for instance
are 0.5 inch from hole to hole. I lay all chips with + and - buses running
under the chips. It's like a puzzle, fun!
I tape the paper onto the PC board (with clear tape covering the design). I
use my Dremel Moto tool on its drill press ($45 for the press from
Micro-Mark plus some special small-bit chucks and bits) to drill the holes.
I take off the drawing, flip it upside-down and use it as a guide to draw
the traces on the copper side using a Sharpie pen. Etch and you're done!

As for Macintosh software, look at:

Douglas Layout Freeware
http://www.douglas.com/

PCBWarrior
ftp://ftp.informatik.rwth-aachen.de/pub/packages/PlatoonPCB/


-----------------------------------------
Reverend bluE wrote:

> Rob wrote:
> > EAGLE PCB is the easiest and the best and has a full working demo
> > version.. wonderful software..
>
> and I inquire:
>
>  is this for PC?  (it probably is, so on to my next q)  is there any PCB
> design software for Macs?
> -ben






From Neil.Johnson at camcon.co.uk  Tue Jan 12 10:12:03 1999
From: Neil.Johnson at camcon.co.uk (Neil Johnson)
Date: Tue, 12 Jan 1999 09:12:03 +0000
Subject: Day job
Message-ID: <802566F7.0030D76A.00@CCLGatewayUK-01.camcon.co.uk>

(not wanting to be left out ...)

I am a Chartered Electronics Engineer for a large engineering consultancy
firm here in Cambridge, UK.  I design everything from hardware (analogue,
digital, FPGA, ASIC) to software (various assembler, C, little bit of
Tcl/Tk and LabView), usually sitting on the fence between these two
disparate regimes.  I've been doing this stuff professionally (that is, for
money) for about 10 years, and I've also picked up a couple of degrees
along the way.  Privately, I've been soldering things together for _much_
longer (almost 20 years I reckon) and had an active interest in electronic
music synthesis for the best part of 15 years, building various synthesizer
gadgets and experiments along the way.  Check out my web page for some
musings on Walsh function synthesis.

My current home set up mostly consists of ready-made stuff (Emu, Roland,
Yamaha, etc) which, blush, shame, I am slowly enhancing with home-brew
things.  My current project is a MIDI routing unit so I can at last get a
grip on patching my MIDI gadgets.  I built one a few years back, and it was
published in the UK magazine Practical Everyday Electronics, but it only
has 6 channels and is manually switched.  This new design will have 8
channels and will be digitally controlled, and will respond to MIDI
messages as well as front-panel controls, 64 patch memories, direct SysEx
control, etc.  After this one, well, I've got plenty of other ideas waiting
to be realised (MIDI message processor, polyphonic digital-analogue-hybrid
synth, Walsh function synth, etc)

If you read the magazine produced by Maplin Electronics ("Electronics &
Beyond - The Maplin Magazine") you've probably come across my IBUS system
in the last year or so.

So, tuppence spent (or 2 cents for our American cousins)

Neil
------

+======================================================+
|     Neil Johnson  BEng(Hons) MSc CEng MIEE MIEEE     |
|         http://members.xoom.com/Neil_Johnson         |
|"I can hardly speak for myself, let alone my employer"|
+======================================================+





From blacet at metro.net  Tue Jan 12 10:13:22 1999
From: blacet at metro.net (John Blacet)
Date: Tue, 12 Jan 1999 09:13:22 +0000
Subject: DIY MIDI Clock-Arpeggiator Clock Convertor?
References: <l03130300b2c10dc7dd47@[203.37.26.241]>
Message-ID: <369B1231.2F36@metro.net>

Hi Simon:

Have you looked at our MIDI-Sync PIC IC on the website below?

Regards.
-------------------------
John Blacet
Blacet Research Music Electronics
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html




From zzynt at swipnet.se  Tue Jan 12 10:29:26 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 12 Jan 1999 01:29:26 -0800
Subject: my ssm2164 quad VCO again
References: <2BF6F749A4A3D11185AD00A0C94CF67A4D6880@demon>
Message-ID: <369B15F6.25D8@swipnet.se>

Roman Sowa wrote:

> Anyway I'd be thankful for any comments about this website.
> BTW I'm not so good at this as some of you are, so don't expect
> to find any Java, frames, cool graphics etc.
> Just plain text, and schemos
> 
> Ah, the URL!
> here it is: http://www.multimania.com/romcio
> 
> Roman

Wery well and nicely done Roman.
Interesting approach you have done with the ssm2164!

BJ



From john at nrtg.com  Tue Jan 12 10:36:43 1999
From: john at nrtg.com (John Tuffen)
Date: Tue, 12 Jan 1999 09:36:43 -0000
Subject: day job
Message-ID: <c=GB%a=_%p=NRTT%l=MARIUS_N-990112093643Z-4@pc130.nrtg.com>

Well, Seeing as everyone(?) else has chipped in, I'll tell you what I
do.

I'm a software engineer for a real-time software company - largely
working on automotive systems (CAN-bus based if anyone wants to know!).
We have just released a product to market which is the smallest, fastest
real-time-embedded OS on the planet (really! see
http://www.nrtg.com/nrta/ ).

Synths etc. are strictly spare-time hobbies..... although there are a
couple of DIY-ers here at work too!!

cheers,

john..



From rsowa at WizjaTV.pl  Tue Jan 12 11:06:22 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 12 Jan 1999 11:06:22 +0100
Subject: day job...
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6883@demon>

I've never seen so wide response to any question ever...
So here's mine:

I work for Polish digital satelite TV (www.wizjatv.pl)
and run big switch, where our toll-free numbers are serviced.
This is my first job since I finished school and it get's boring now.
I've been soldering since I was in my early teens, and never stopped.
DIYing is my only way to keep up to date with all new stuff in electronics.
Sometimes I even get paid for it when I do little project for someone else.

Roman



From jorgen.bergfors at idg.se  Tue Jan 12 11:26:11 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 12 Jan 1999 11:26:11 +0100
Subject: PCB layout software
Message-ID: <TFSJCJIH@idg.se>

>>  Well, why don't you use a dedicated software ? You can still use a
>> manual routing, but you have back-annotation, electrical
>>  rule check, etc... that way, if you have a correct schematic, you're
>> sure to have a correct pcb (electricaly speaking).
>> 

>Shure.

>But one thing is also shure:

>It takes a hell lot of time to set up the system.  You have to define
>object bodys, schematic views, simulation code, pinouts and a footprint
>for EVERY single type of component you use.  Most probably you have to
>define a lot of resistor and capacitor types because of varying wire
>length (instead using wire bridges you often use resistors with long
>wires to get over some pcb trakcks, whenever possible etc.).

>Most software packages I know have lots of 74LSXXX in their librarys,
>and maybe a 741, but most of our analog stuff is not there.

>Not to mention all the debugging afterwards, because of wrong defined
>pinouts etc. etc. I do this all day long in my day job, every cell I
>design gets a schematic body, simulation code (hand coded if necessary)
>etc etc, and very often I get netlist problems at first, because I've
>forgotten something, or mixed it up.

>I estimated that setting up such a system with all the components you will >ever use will take the time of 3-4 complete modules alltogether. I think that >this is much to much for diy (but ok for professional use).

>So Jorgen has some reason for hand layout.

>Maybe I have just evaluated the wrong software package.
>Then I would be greatfull for any hint to a package which doesn't have all
>the disadvantages I've mentioned above.

A couple more reasons for not using PCB layout software:

1. Most software cost money. A general drawing program is useful for so many other things, that you want to have it in any case. But an extra program for PCB layout means extra cost.

2. When I design the board manually, I can do sneaky things like shaving off portions of pads to make room for a trace that would not otherwise fit. The boards I have seen other people do are not as compact and have more wire links than mine, that's a fact.

3. I can design the schematics symbols to look exactly like I want them. I have emulated the style in Elektor magazine, for nostalgic reasons.

4. I can have beautiful full color parts placement diagrams. My parts symbols look almost exactly like the real parts.

5. It is good brain gymnastics to keep the routing in the head. Occasionally I make a mistake, but it is necessary to build a prototype anyway. Board layout errors are usually easy to correct on the prototype.
Nowadays I make a prototype board before i try out the circuit at all. So I can test the board at the same time as I test the circuit itself. If I need to add say an IC, I make a small Veroboard "dongle". Then when everyting works as it should, I correct the board in Corel Draw and etch a new one. This is quick and easy because I print the films on transparencies and use pre-coated boards that give perfect results every time.

/Jorgen




From alexandr at irit.fr  Tue Jan 12 11:48:18 1999
From: alexandr at irit.fr (Karl ALEXANDRE)
Date: Tue, 12 Jan 1999 11:48:18 +0100
Subject: PCB layout software
References: <199901120743.IAA02523@window.intermetall.de>
Message-ID: <369B2872.E85E0AC0@irit.fr>

> It takes a hell lot of time to set up the system.  You have to define
> object bodys, schematic views, simulation code, pinouts and a footprint
> for EVERY single type of component you use.  Most probably you have to

	95% of the component I use are in the packages.

> define a lot of resistor and capacitor types because of varying wire
> length (instead using wire bridges you often use resistors with long
> wires to get over some pcb trakcks, whenever possible etc.).

	One good thing with eagle is when you capture a schematic, you can
	tell the size of a component (for passive ones). Later, when you	
	route your board, you can change the body of anything very simply.
	If you your resistor was to short, just change the distance between
	pads with another footprint...
	
> Most software packages I know have lots of 74LSXXX in their librarys,
> and maybe a 741, but most of our analog stuff is not there.

	See above. Sure if you want an AD538 you have to create it yourself...

> I estimated that setting up such a system with all the components you will ever use will take the time of 3-4 complete modules alltogether.
> I think that this is much to much for diy (but ok for professional use).

	Sure, the first time you use a software, it takes 2 hours to board
	a blinking led :) But after...

	In 3 hours, with orcad, i didn't manage that.... I'm not intelligent :)	

> > So Jorgen has some reason for hand layout.

	Sure, for simple analog modules, you can... But i also make some
digital
	stuff on double sided eurocards... I used to hand-wire some module, but
	it isn't reliable, at least durable...
	
	We have all habits which are difficult to change :)

	Don't start a "my method is the best" thread...

	

				Karl.

	PS: speaking of th AD538, did anybody checked this "Analog
computational unit" at
	analog device. It's a chip which compute 
	Vout = Va * ( (Vb/Vc) ^^ m)
	Analog device gives free samples of this thing, i have two and will
test them soon...



From rsowa at WizjaTV.pl  Tue Jan 12 12:35:39 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 12 Jan 1999 12:35:39 +0100
Subject: ODP: Easy chip question
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6885@demon>

244 is not an inverter
it is 8 buffers i.e. acts like 2-state amplifier with the ability
to turn outputs into high impedance.
And yes, it has strangely reversed buffers inside.
I think it is from the times when 4-bit uC were popular.
If you want buffers, use 245 device. It has not only all buffers
turned in one direction, but you can also change that direction!
(bidirectional buffer)
Or 241, which is simply one-direction 8-bit buffer

And use HC245. LS are relict of the past (HC too, but not so distant past)

Duh answer: they're not passive devices. Require +5V

Roman

> -----Oryginalna wiadomo??-----
> Od:	Irish [SMTP:irish at eskimo.com]
> Wys?ano:	10 stycznia 1999 13:25
> Do:	DIY
> Temat:	Easy chip question
> 
> My questions are: this chip (74LS244) has individual inverters, plus also
> has
> additional inverters in it that chain the individual ones together by
> their
> base (? I guess - they are drawn as a triangle, and this comes out the
> side).
> 
> Also, (duh question) do I need to supply +V and gnd for the chip to work,
> or can
> it be used as a passive(?) device? 
> 
> Thank you, 
> Irish



From zzynt at swipnet.se  Tue Jan 12 12:41:49 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 12 Jan 1999 03:41:49 -0800
Subject: Magnus book list!
Message-ID: <369B34FD.3824@swipnet.se>

Once again ,i would recomend any one who
needs info on electronic books .musik or not to go to :

http://www.it.kth.se/~e93_mda/synths/books.html

Good work Magnus!!

BJ



From rsowa at WizjaTV.pl  Tue Jan 12 13:15:03 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 12 Jan 1999 13:15:03 +0100
Subject: ODP: Filters
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6886@demon>

This is filtering the hard way IMO, but also very interesting.
Like others already posted it will cause problems between IFFT windows
if you don't overlap them in a good way.
Somehow an analogy to MiniDisc rises - it is afterall some Discrete
Cosine Transforms similar in a way to your proposition,
and it sounds not bad (although I wasn't satisfied with low frequency
sawtooth recordings)
It's a huge topic anyway.
Personally I would go the usual way - IIR or FIR.

According to Magnus Danielson's post, I wouldn't agree with him.
At low frequencies IIR coefficients are dangerously closing 0 or 1
and we deal with resolution problems, where 16 or even 24 bit
for coeficient is not enough and filter becomes unstable.

Roman

> -----Oryginalna wiadomo??-----
> Od:	James Jackson [SMTP:james at newd.demon.co.uk]
> Wys?ano:	11 stycznia 1999 20:48
> Do:	Roman Sowa
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: ODP: Filters
> 
> >Could you specify what you mean by Fourier Transform based filters?
> 
> Yes, I'll try, but I havn't learnt much about them yet. It would seem
> through feedback from the list, that fourier transforms are not the best
> way
> to do filtering on DSPs, but I'll try to explain anyway. Fourier
> transforms
> allow you to extract the amplitude and other usefull stuff of any given
> frequency when provided with a spectrum of audio (Or more usually, RF)
> data.
> You can use this information to make any type of filter you want.
> 
> 



From Juergen.Haible at nbgm.siemens.de  Tue Jan 12 13:30:46 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 12 Jan 1999 13:30:46 +0100
Subject: AW: my ssm2164 quad VCO again
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582011A6EBB@nbgm336a.nbgm.siemens.de>

	>Wery well and nicely done Roman.
	>Interesting approach you have done with the ssm2164!

I like your discrete VCA !

JH.



From halmans at globalxs.nl  Tue Jan 12 15:05:52 1999
From: halmans at globalxs.nl (Maarten Halmans)
Date: Tue, 12 Jan 1999 15:05:52 +0100
Subject: Day job
Message-ID: <369B56C0.32AFD592@globalxs.nl>

I am a first year student, studying electronic engineering. A couple of
years ago I got interested in electronic music and started to make music
with a couple of friends. We released two records and did a couple of
live performances. After a while a got more and more interested in
building my own synthesizers. So I went back to school.

Maarten





From rsowa at WizjaTV.pl  Tue Jan 12 15:32:55 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 12 Jan 1999 15:32:55 +0100
Subject: ODP: Digital DIY synths and DSP stuff... and drums
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D6889@demon>


> -----Oryginalna wiadomo??-----
> Od:	Ben Stuyts [SMTP:ben at stuyts.nl]
> Wys?ano:	12 stycznia 1999 00:37
> Do:	Roman Sowa
> DW:	synth-diy at mailhost.bpa.nl
> Temat:	Re: Digital DIY synths and DSP stuff... and drums
> 
> On Mon, 11 Jan 1999, Roman Sowa wrote:
> 
> > What kind of 16-bit converters?
> > AD1877, AD1859, AD1851 from Analog Devices
> > Sound Quality - 1851 low noise, 1859 low distortion
> > 1877 - you ned no better ADC
> > unles you make heavy in $$$ digital mixing console
> 
> Aha, so none of the combined a/d and d/a's are any good?
> I see some of them are single +5V supply. Very convenient!
	[Roman Sowa]  
	Well, there's one CODEC which I find good. It is a Crystal
	device, 20-bit ADC and DAC, but expect them to be pricey
	(I got it as samples)

> Long time ago I built a full analog drum computer.
	[Roman Sowa]  
	So, I guess you had a lot of free time back then ;-)




From clark at andrews.edu  Tue Jan 12 15:38:44 1999
From: clark at andrews.edu (Tony Clark)
Date: Tue, 12 Jan 1999 09:38:44 -0500 (EST)
Subject: PCB layout software
In-Reply-To: <TFSJCJIH@idg.se>
Message-ID: <Pine.SOL.3.91.990112083445.29859A-100000@edmund.cs.andrews.edu>

   A few replies here...

> >It takes a hell lot of time to set up the system.  You have to define
> >object bodys, schematic views, simulation code, pinouts and a footprint
> >for EVERY single type of component you use.  Most probably you have to
> >define a lot of resistor and capacitor types because of varying wire
> >length (instead using wire bridges you often use resistors with long
> >wires to get over some pcb trakcks, whenever possible etc.).

   In a good package program, most of the work has been done for you.  
They usually come with a fairly extensive libraries so that you do not 
have to do more than pull in a component and assign a footprint.
   Also, unless you really need it, simulation code is unnecessary in PCB 
software.  It is nice to have when you are actually _designing_ circuits, 
I suppose, but for just schematic entry and PCB layout, not needed.

> >Most software packages I know have lots of 74LSXXX in their librarys,
> >and maybe a 741, but most of our analog stuff is not there.

   Well I remember when the Engineering dept. was trying out MicroSim as 
a possible schematic entry/PCB layout software for the PCB class I 
teach.  I had already been using windows OrCAD (learned on DOS OrCAD!) 
for a good year, so I told them it'd be easier to use what I knew instead 
of retraining myself on a new package.
   But I went ahead and evaluated the MicroSim package and was abhorred 
to learn that the libraries were vastly incomplete!  They were seriously 
lacking in analog component primitives (ie no transistor pinout 
variations) and completely missing interconnection components!

> >Not to mention all the debugging afterwards, because of wrong defined
> >pinouts etc. etc. I do this all day long in my day job, every cell I
> >design gets a schematic body, simulation code (hand coded if necessary)
> >etc etc, and very often I get netlist problems at first, because I've
> >forgotten something, or mixed it up.

   Again, a decent program should already have a library of parts.  
Although I will say that even OrCAD goofed in this regard!  When the 
Engineering dept. bought their copies of OrCAD for their lab, I made the 
awful discovery that all of the IC parts in the libraries had the power 
pins incorrectly assigned!  Funny that it wasn't goofed in the copy I 
have.  :/
   So maybe you really can't escape some amount of hardship, even with 
top of the line programs!

> A couple more reasons for not using PCB layout software:
> 
> 1. Most software cost money. A general drawing program is useful for 
> so many other things, that you want to have it in any case. But an extra 
> program for PCB layout means extra cost.

   This is true.  OrCAD tops in at 10 grand with the advanced PCB layout 
program!  But comes in much less for educational institutions!  And of 
course there are MUCH more expensive packages out there!  I know of a few 
that are in the 40-60 grand range!  The nice thing about OrCAD is that 
you can buy different levels of software so that you don't have to pay 
for extra features (such as autorouting - see below).

> 2. When I design the board manually, I can do sneaky things like 
> shaving off portions of pads to make room for a trace that would not 
> otherwise fit. The boards I have seen other people do are not as compact 
> and have more wire links than mine, that's a fact.

   Firstly, any decent PCB program should allow you to assign different 
kinds of pads!  With OrCAD you can either change pads on the fly or you 
can edit the footprint library to customize regularly used footprints.
   As far as wiring, this is an art, not a science.  Absolutely NO PCB 
program on the planet will save you from badly routed PCBs!  The most 
unreliable feature of any PCB program is the auto-router!  I have yet to 
see one handle high-density (compact) designs!

> 3. I can design the schematics symbols to look exactly like I want 
> them. I have emulated the style in Elektor magazine, for nostalgic reasons.

   Any good PCB program will let you edit or create your own part library.

> 5. It is good brain gymnastics to keep the routing in the head. 
> Occasionally I make a mistake, but it is necessary to build a prototype 
> anyway. Board layout errors are usually easy to correct on the prototype.

   Well everyone should be doing this!  I always prototype my boards 
before committing to pre-production prototype circuit boards!  It costs 
too much to continually run new batches of circuit boards if you discover 
flaws along the way.  Far better to hand-wire or vero-board a circuit and 
work out flaws first!
   Really, we can discuss what programs are better or what features they 
should have all day!  I think that we all have a method that suits our 
needs.  For those that are still looking, all I can say is get the best 
that you are willing to afford, because it makes a world of difference!
   To me, the most important thing to determine is whether or not you'll 
be doing your own circuit boards or if you will be farming them to 
outside sources.  If you are farming them out, then be sure it will 
support Gerber photoplotter files and use Excellon format.  These are 
universal with PCB fab houses (in the US, anyway).  This is also a good 
idea if you want to share your PCB files with others.  Anyone can then 
take the data and have circuit boards made from those files without any 
further editing!
   Anything else beyond file output format is purely up to your own 
personal preference!
   This is a great thread!

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From simon at dynamite.com.au  Tue Jan 12 15:49:26 1999
From: simon at dynamite.com.au (Simon)
Date: Wed, 13 Jan 1999 00:49:26 +1000
Subject: DIY MIDI Clock-Arpeggiator Clock Convertor?
In-Reply-To: <802566F7.0030D76A.00@CCLGatewayUK-01.camcon.co.uk>
Message-ID: <l03130300b2c10dc7dd47@[203.37.26.241]>

Can anyone point me to information about building a MIDI Clock-Arpeggeator
Clock convertor?

I want to be able to turn MIDI Clock into a clock signal that will drive
the arpeggiator/sequencers in my pre-MIDI synths by their clock inputs.

I would like the outputed arpeggiator clock to offer different divisions of
the incoming MIDI Clock, and be switchable to different MIDI channels. Does
this sort of DIY project exist anywhere?


I have a Roland SH-101. Roland Jupiter 6, Moog Source and a friend has a
Roland Juno 6. All of these would benifit from a synced clock from my MIDI
drum machines.

I also have a Sequential Circuits Drumtrax which has a clock input, but I
have no manuals so I'm not sure if it is a different signal to the others.
It would be good to sync the Drumtrax to MIDI clock as well, as the inbuilt
tempo doesn't seem to have very small increments so I havn't used it much,
but maybe I can just sync the Drumtrax tempo directly to MIDI Clock coming
in it's MIDI IN, does any know or have a manual and could tell me?


Thanks
Simon
Canberra
AUSTRALIA





From ryckebu at subasehp.san.mrms.navy.mil  Tue Jan 12 16:04:49 1999
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Tue, 12 Jan 1999 15:04:49 +0000
Subject: Day Job
Message-ID: <199901122311.PAA28832@subasehp.san.mrms.navy.mil>

Hey All, I am Jules Ryckebusch. I have 18 years in US Navy as a 
Nuclear/Electrical engineer kind of guy. I built my first PAiA kit 
when I was 16 and now I design an occasional thing or two for them. I 
have a home studio and have built everything except for the DAT 
machine and a couple outboard Digital Processors.

Jules



From budweiser at ozemail.com.au  Tue Jan 12 16:15:08 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Wed, 13 Jan 1999 01:45:08 +1030
Subject: Sequencer microprocessors
Message-ID: <00d501be3e3e$5a5580c0$eed26ccb@ppp.ozemail.com.au>

I am really interested in the idea of a cloning the 909 drum machine,
now that i have enough information about the circuits (especially the
the sample playback circuits for the hihats/cymbals).

What sort of processor would be best for such a design? Keeping in
mind I want to add more recent features found on modern instruments
like realtime midi control of the sounds, and leaving the sequencer
running while changing from play to write mode (like the 606).....

I haven't done much on uP's, apat from a PLC and one of the simple
motorola devices....

<bUd>




From brun at bart.nl  Tue Jan 12 16:32:26 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Tue, 12 Jan 1999 16:32:26 +0100
Subject: Well, website help implemented
Message-ID: <199901121533.QAA21937@smtp1.xs4all.nl>

I just gave a first shot at a page with links to synth-manuals and 
commercial schematics on the web. Comments and input more than 
welcome! Look (of course) in the schematics-DIY section.

http://www.bart.nl/~brun/index.htm



-> Brun, met een dakje op de u.

Nu aan het knutselen op http://www.bart.nl/~brun/index.htm



From john at nrtg.com  Tue Jan 12 17:32:31 1999
From: john at nrtg.com (John Tuffen)
Date: Tue, 12 Jan 1999 16:32:31 -0000
Subject: DIY MIDI Clock-Arpeggiator Clock Convertor?
Message-ID: <c=GB%a=_%p=NRTT%l=MARIUS_N-990112163231Z-45@pc130.nrtg.com>

Hi,
	If you have access to a PIC programmer then my MIDI->Sync converter may
be what you want.... see
http://www.york.ac.uk/~jat5/electronics/PIC/sync.html .

It converts MIDI clocks into various pulse trains (from 48ppqn down to
1ppqn) The source code for the PIC is available via email :) (It'll soon
be on the web site!!!) since I am no longer offering the sale of
pre-programmed PICs for this project.

cheers,

john..

>-----Original Message-----
>From:	Simon [SMTP:simon at dynamite.com.au]
>Sent:	Tuesday, January 12, 1999 3:35 PM
>To:	synth-diy at mailhost.bpa.nl
>Subject:	DIY MIDI Clock-Arpeggiator Clock Convertor?
>
>Can anyone point me to information about building a MIDI Clock-Arpeggeator
>Clock convertor?
>



From mmcintos at ball.com  Tue Jan 12 17:55:14 1999
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Tue, 12 Jan 1999 09:55:14 -0700
Subject: Day job
Message-ID: <09DB74475204D1119C8200805F19D00302E20BDC@aeromsg1.ball.com>

I am an optical engineer at Ball Aerospace in Boulder, Colorado, USA.  I
have a masters in physics.  In a pervious life I worked at the Oak Ridge
National Laboratory.  I can tell you little about that, and you really don't
want to know.  At Ball, I design, test, trouble shoot and integrate optical
subsystems into larger systems.  Mostly space based instrumentation, earth
imagers, space based telescope stuff, laser tracking and illumination,
etc....  It's fun and challenging.  However, I have always loved
synthesizers since I saw a demonstration of a Moog synthesizer in the public
library at age 10!  (The Moog consisted of a 3 boxes with modules in it and
a separate keyboard.  The thing would fold up so that the outer two boxes
closed over the center one.  If anyone knows what kind of Moog that was, I
appreciate the information!)  I took a break from music and synthesizers for
about 10 years.  But, the love of analog sound synthesis hit me like a ton
of bricks.  So, now I am forced to learn about analog electronics.  Long
term goal and dream: build a polyphonic analog synthesizer with 8 voices
which beats the memorymoog!




From mmcintos at ball.com  Tue Jan 12 18:03:56 1999
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Tue, 12 Jan 1999 10:03:56 -0700
Subject: No PCB layout software!
Message-ID: <09DB74475204D1119C8200805F19D00302E20BDD@aeromsg1.ball.com>

As a novice, I really like what MAP uses: PCB Development Tools by A.
Waldherr Software Engineering 

http://www.waldherr.com/

I find it has just the right amount of features and is super easy to use.
Cost: $50 US.  The Eagle stuff looked good to, but I need boards larger than
X by Y.

If you don't want auto-routing you should check out ExpressPCB

http://www.expresspcb.com/

They will take your circuit and make PCB's for you from it!  The software is
free and I think it will print out to your printer too.

Have fun!

Malcolm



From td at pixar.com  Tue Jan 12 18:41:44 1999
From: td at pixar.com (Tom Duff)
Date: Tue, 12 Jan 1999 09:41:44 -0800
Subject: ODP: Filters
In-Reply-To: Ethan Duni <eduni@ucsd.edu>
        "Re: ODP: Filters" (Jan 11,  4:17pm)
References: <199901120017.QAA13988@smtp.ucsd.edu>
Message-ID: <9901120941.ZM195425@marvin>

> On the other hand, another approach might be to not use an FFT at all; just
> start in the frequency domain and build your oscillators as collections of
> harmonics with various amplitudes and phases
...
> incidentally, i have a big design project coming up in the next couple of
> years for my degree.  what i've been thinking of doing is sort of along
> these lines.. I'm calling it a convolution-synth for lack of a better term;
> the idea is to start in the frequency domain as described above.

Ph. Depalle and Xavier Rodet have worked out the details of how to do this --
the hairiest problem is keeping signals in phase from frame to frame so you
don't get phase cancellation when adding up the output signal.

There's a good introduction on the web at
http://cnmat.cnmat.berkeley.edu/~adrian/FFT-1/FFT-1_ICSPAT.html

-- 
Tom Duff.  At the end, one person called for an encore.



From simon at dynamite.com.au  Tue Jan 12 19:16:20 1999
From: simon at dynamite.com.au (Simon)
Date: Wed, 13 Jan 1999 04:16:20 +1000
Subject: Sequencer microprocessors
In-Reply-To: <00d501be3e3e$5a5580c0$eed26ccb@ppp.ozemail.com.au>
Message-ID: <l03130300b2c1416601a3@[203.37.26.241]>

>I am really interested in the idea of a cloning the 909 drum machine,
>now that i have enough information about the circuits (especially the
>the sample playback circuits for the hihats/cymbals).
>
>What sort of processor would be best for such a design? Keeping in
>mind I want to add more recent features found on modern instruments
>like realtime midi control of the sounds, and leaving the sequencer
>running while changing from play to write mode (like the 606).....
>
>I haven't done much on uP's, apat from a PLC and one of the simple
>motorola devices....


Sounds interesting, I would be interested if you get it together. If not in
the whole thing, then just the 808/909 kick/snare sound circuits themselves
fired by control voltage would be enough for me.

Simon
Canberra
AUSTRALIA





From buchi at dci.de  Tue Jan 12 19:54:34 1999
From: buchi at dci.de (Michael Buchstaller)
Date: Tue, 12 Jan 1999 18:54:34 GMT
Subject: Paia Midi2CV8 kit in germany ?
Message-ID: <369b9984.14592620@mail.dci.de>

Hello list members,

i want to order the midi2CV8 kit from Paia.
But i think shipping from the US to germany (where i do live) will
be quite costly, maybe there is anybody out there who wants to
get this kit, too ?
Then i would order two kits from Paia at their discount price for 2
units, and i think UPS charges will differ minimally whether the packet
includes 1 or 2 kits.
If anyone is interested, please send me PM.

Thank you !


-Michael Buchstaller



From cyborg0 at GlobalEyes.net  Tue Jan 12 20:11:32 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Tue, 12 Jan 1999 13:11:32 -0600
Subject: Sequencer microprocessors
References: <00d501be3e3e$5a5580c0$eed26ccb@ppp.ozemail.com.au>
Message-ID: <369B9E64.9593CEBF@globaleyes.net>

"Budweiser [FTS]" wrote:
> 
> I am really interested in the idea of a cloning the 909 drum machine,
> now that i have enough information about the circuits (especially the
> the sample playback circuits for the hihats/cymbals).
> 
> What sort of processor would be best for such a design? Keeping in
> mind I want to add more recent features found on modern instruments
> like realtime midi control of the sounds, and leaving the sequencer
> running while changing from play to write mode (like the 606).....
> 
WEll, a PIC would be good enough just to control the interface and
memory. You would still prlly have to go down and dirty and use discrete
logic otherwise you will be debugging forever with a play/write
simultaneous mode.
Rob



From oakley at techrepairs.freeserve.co.uk  Tue Jan 12 20:31:04 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Tue, 12 Jan 1999 19:31:04 -0000
Subject: Mixer schematics
Message-ID: <000901be3e63$08519000$2478883e@default>

Hi Arpad and all,

My advice. Buy one. The price of Behringer, Spirit and Mackie is now so
good it is very unlikely you will be able to build cheaper. I built my
own out of front panels thrown in the skip outside the factory, but it
is the components that are pricey. Mainly because of the large number of
pots. You will be buying pots at about 1UKP a go. Soundcraft get them
for a tenth of that, and the knobs are less still. The older Spirit
range are still being sold. These are good value and use do not use SMD
parts, and are therefore very easy to mod.

Regards,

Tony Allgood, Cumbria, UK

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html



>Hello Tony (all),

I understand that you probably know everything about mixers, equlizers,
etc. I would like to build for myself a 6-8 channel home-studio mixer
which has e.g. the following controls for each channel: gain, 3-channel
equ, pan, effect, volume. So I'm looking for some schematics,
(relatively good quality -> fet opamps?). Could you help me?

Thanks in advance,

Arpad.





From td at pixar.com  Tue Jan 12 20:59:57 1999
From: td at pixar.com (Tom Duff)
Date: Tue, 12 Jan 1999 11:59:57 -0800
Subject: Day job
In-Reply-To: "McIntosh, Malcolm" <mmcintos@ball.com>
        "RE: Day job" (Jan 12,  9:55am)
References: <09DB74475204D1119C8200805F19D00302E20BDC@aeromsg1.ball.com>
Message-ID: <9901121159.ZM146314@marvin>

Hi.  I just joined synth-diy.
I write 3-D image generation
software at Pixar Animation
Studios in northern California.
The rain storm at the end of
A Bug's Life was my responsibility.
I've done similar work for more than
20 years now.

In my spare time I've built musical
instruments and used computers and
analog electronics to compose music
for more than 30 years.  In the
beginning I worked in a traditional
tape studio, using test equipment,
tape recorders, custom-built gadgetry &
a lot of splicing tape, and worked from
scores produced on mainframe computers.
I won't bore you with details of subsequent
spins of the technology wheel.  Lately,
I've started building analog gadgets again,
and even things with acoustic components
(strings, plates, pipes), although usually
electrically excited and processed.

For a holiday performance this Christmas,
I built a thing that interfaced the guts
of a pile of Christmas-card noisemakers
(you know, the ones that play Jolly Old St
Nicholas in square waves when you open the
card) to some guitar toys.

-- 
Tom Duff.  Strange Mathematical, Rhythmic Equations



From magnus at analogue.org  Tue Jan 12 21:13:32 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 12 Jan 1999 21:13:32 +0100
Subject: Day job
Message-ID: <199901122013.VAA27207@mail2.it.kth.se>

Hi!

Well, this day-job thread seems bubbeling, so I just thought I would
join you.

Well, I work for Net Insight AB (http://www.netinsight.se/) a small
startup company in Sweden. We develop network products based around
the DTM technology. I act as a system architect and designs and invent
signaling protocols, hardware, software, ASIC etc. while helping out
my colleages. Lately I have been designing a completely digital and
tweakable PLL for our ASIC, implementing it in VHDL (which I just
learned). Not very analog, but I try to be pretty linear about it ;)
Fortunatly there is some analog asspects to higher speeds, so I keep
the mind fresh ;)

Synt at work does not really means the same as at home.

Cheers,
Magnus



From magnus at analogue.org  Tue Jan 12 21:21:15 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 12 Jan 1999 21:21:15 +0100
Subject: gnuplot
In-Reply-To: Your message of "Mon, 11 Jan 1999 16:30:27 +0100 (MET)"
References: <199901111530.QAA26333@window.intermetall.de>
Message-ID: <199901122021.VAA27313@mail2.it.kth.se>

>>>>> "MC" == Martin Czech <martin.czech at intermetall.de> writes:

 MC> gnuplot is a very nice tool for visualising data and formula etc.
 MC> I don't need to explain why some thing like this is very usefull for 
 MC> diy, ok ?

Not only is Gnuplot usefull, but also Octave a free Matlab-ish tool.
Octave uses Gnuplot for plotting, but processing stuff in Octave is
much more convenient than Gnuplot alone.

 MC> And it's free. Does anybody know if there is a windooze version ?

 MC> I have checked http://www.cs.dartmouth.edu/gnuplot_info.html
 MC> but there's only a dos version in protected mode, I fear.

 MC> Is there anything else free and comparable ?

There are several tools, but I never took the time to investigate all
of them since Octave and Gnuplot fullfills most of my neads. Octave
has many usefull processing routines at hand, and if they don't fill
the need it is not hard to add some of your own.

Cheers,
Magnus



From g.ramsay at easynet.co.uk  Tue Jan 12 21:32:12 1999
From: g.ramsay at easynet.co.uk (Gordon Ramsay)
Date: Tue, 12 Jan 1999 20:32:12 -0000
Subject: Day job
Message-ID: <002501be3e6a$a2352540$f340d4d4@oemcomputer>

Seeing as everyone else has.......

Hello,

My name is Max Ramsay, I am in the Final (Honours Year) of a degree in Electronics and Music Technology at Caledonian University in Glasgow, Scotland. The course is pretty interesting and I am focusing on DSP audio + Synth design for my thesis, although my main base is in  analog electronics, however this may change once I get the DSP stuff going.

I have worked for a major electronics manufacturer here in Scotland debugging their malfunctioning mobile phone designs and manufacturing process. In my spare time I concentrate on trying to make old Moogs stay in tune long enough to get them recorded.

Cheers 

Max Ramsay

P.S. Out of interest is their anyone else on the list working on synths in Scotland?
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From capry at bulldog.unca.edu  Tue Jan 12 21:44:00 1999
From: capry at bulldog.unca.edu (Chad Ashley Pry)
Date: Tue, 12 Jan 1999 15:44:00 -0500 (EST)
Subject: Synar(star instruments0
Message-ID: <Pine.OSF.3.95.990112154243.23089C-100000@bulldog.unca.edu>

Hello.

  I'm trying to get ahold of schematics and a manual for the star
instruments Synare9 the one that looks like a flying saucer) Please let me
know if you can help me out. thanks.

Sincerly,
  cHAD pRY
tIMiNaCTiON
http://listen.to/timinaction





From magnus at analogue.org  Tue Jan 12 22:01:15 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 12 Jan 1999 22:01:15 +0100
Subject: ODP: Filters
In-Reply-To: Your message of "Mon, 11 Jan 1999 19:47:58 +0000"
References: <1.5.4.32.19990111194758.00679144@pop3.demon.co.uk>
Message-ID: <199901122101.WAA27620@mail2.it.kth.se>

>>>>> "JJ" == James Jackson <james at newd.demon.co.uk> writes:

 JJ> At 10:54 11/01/99 +0100, you wrote:
 >> Hi,
 >> good luck on this project...
 >> It's nice as soon as you'll manage to do it all
 >> 
 >> Could you specify what you mean by Fourier Transform based filters?

 JJ> Yes, I'll try, but I havn't learnt much about them yet. It would seem
 JJ> through feedback from the list, that fourier transforms are not the best way
 JJ> to do filtering on DSPs, but I'll try to explain anyway. Fourier transforms
 JJ> allow you to extract the amplitude and other usefull stuff of any given
 JJ> frequency when provided with a spectrum of audio (Or more usually, RF) data.
 JJ> You can use this information to make any type of filter you want.

 JJ> This may well be wrong, so mail the list if it is!

Well, the Fourier transform exist in two major versions and two
directions, it exist in both continous and discrete time. The
continous time is the actual Fourier transform. The discrete time
Fourier transform is often called DFT (Discrete time Fourier
Transform). The discrete time is really saying that the time is
sampled into discrete events, which is a much diffrent thing than
having continous time.

Now, you may preform the Fourier transform in either forward or
backword direction. If you have the function f(t) in the continous
time t you can transform it into the transfer function F(jw) with the
continous frequency w. This transfer function holds both the amplitude
and phase responce as a complex function of the frequency w (2*pi*f as
usual). The inverse Fourier transform takes the transfer function
F(jw) and returns the function f(t). The discrete time version of the
Fourier transform (DFT and IDFT) will do the same but for discrete
time and discrete frequency.

This FFT thing is just a name for a special set of methods to preform
an DFT analysis in a efficient way, it is the same thing but with
restriction on the number of points that the analysis is being done
for.

Now, how can this possibly apply to filters?
Well, a filter is said to have a transfer function, this function can
also be fully described (assuming that the filter is linear and time
invariant) by it's impulse responce h(t). The transfer function would
thus become H(jw). When you implement a FIR (Finit Impulse Responce)
filter you actually set up the taps from a sample per sample basis of
a delay line. The taps has weigths and is then summed
together. Analysis of this filter shows that the tap values are
equivalent to the impulse responce the filter has, so Fourier
transforming the tap values will give the transfer functions of those
taps. However, in filter design we are much more likely to start of
with some target curve for the transfer function and try to design the
filter parameters to approximate this function. In FIR filter design
you can do this by actually dream up the amplitude and phase responce,
inverse Fourier transform this into a impulse responce and assign it
to the FIR filter.

So, this sounds very optimal indeed, but infact, the hard part is
among others to keep the number of taps down to a minimum as well as
conveying the values in this amount of frequencies that now has gone
down (you have equalently amount of frequencies as well as taps, DC
included, an they are spread in a linear manor between DC and half of
the sampling frequency). So, at 256 frequencies you get 256 taps, and
256 taps means 256 multiplications (which is kind of expensive) and
255 additions (not as expensive). There are methods (Remez-exchange)
to design filters that match some specification but allows the
algorithm to pick a bit more freely, this may cut the number of taps
significantly. Also, if the filter is neatly done it is balanced so
that only half the number of multiplication needs to be done.

Then, many people beleive that Fourier transforms is all the is to
filters, but they should try using LaPlace-transform and its discrete
time version the z-transform.

Cheers,
Magnus



From magnus at analogue.org  Tue Jan 12 22:12:12 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 12 Jan 1999 22:12:12 +0100
Subject: day jobs
In-Reply-To: Your message of "Mon, 11 Jan 1999 12:57:12 -0800"
References: <3.0.3.32.19990111125712.016b3100@mage.qualcomm.com>
Message-ID: <199901122112.WAA27728@mail2.it.kth.se>

>>>>> "BB" == Buck Buchanan <buchanan at qualcomm.com> writes:

 BB> Hi all,
 BB> First off, three cheers to the 14 year old who started this thread - it's
 BB> been interesting to see what everybody else does + I'm stoked for anyone as
 BB> young as that and has rescource as vast as this list! (I didn't have anyone
 BB> to talk to about this stuff when I was 14).

 BB> I'm an RF Engineering Technician at Qualcomm in San Diego.  I work on phone
 BB> designs coming up with mods, tests, some minor design, and lots of
 BB> soldering - the tiny 0402 stuff you solder under a micrsocope.  It's a
 BB> great job!  I never worked above 100KHz before I came here and now I'm Zen
 BB> with 2GHz!  You know RF people refer to the audio band as DC?  I still get
 BB> kinda miffed by it....  ;-)

 BB> One cool thing is I've become sort of a sythnthesizer guru around here
 BB> which is an interesting parellel to my music synth stuff.... except these
 BB> synths run at 1.9GHz.  Working with RF makes you really appreciate how
 BB> straight forward life is below 1MHz!

Oh, how true!

Are you all aware just how many trick you are using just cause you are
so near DC? There's a lot of them!

There are so called electronic experts (at time self-appointed such)
that just can't deal with the > 1 GHz range simply since things no
longer behave as they thought. Actually things have gone hey-wire way
before you reach 1 GHz. Is that cap really acting as a capacitor?
Is that copper plane really at the same level all over? Why is there
no signal here? Where did THAT signal come from? Oh, is this box
radiating????

Cheers,
Magnus



From LEG at btinternet.com  Tue Jan 12 22:29:31 1999
From: LEG at btinternet.com (george & lorraine)
Date: Tue, 12 Jan 1999 21:29:31 -0000
Subject: Day job moog
Message-ID: <01be3e72$a41b50c0$LocalHost@windows95>


-----Original Message-----
From: McIntosh, Malcolm <mmcintos at ball.com>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: 12 January 1999 18:52
Subject: RE: Day job


>I am an optical engineer at Ball Aerospace in Boulder, Colorado, USA.  I
>have a masters in physics.  In a pervious life I worked at the Oak Ridge
>National Laboratory.  I can tell you little about that, and you really
don't
>want to know.  At Ball, I design, test, trouble shoot and integrate optical
>subsystems into larger systems.  Mostly space based instrumentation, earth
>imagers, space based telescope stuff, laser tracking and illumination,
>etc....  It's fun and challenging.  However, I have always loved
>synthesizers since I saw a demonstration of a Moog synthesizer in the
public
>library at age 10!  (The Moog consisted of a 3 boxes with modules in it and
>a separate keyboard.  The thing would fold up so that the outer two boxes
>closed over the center one.  If anyone knows what kind of Moog that was, I
>appreciate the information!)  I took a break from music and synthesizers
for
>about 10 years.  But, the love of analog sound synthesis hit me like a ton
>of bricks.  So, now I am forced to learn about analog electronics.  Long
>term goal and dream: build a polyphonic analog synthesizer with 8 voices
>which beats the memorymoog!
>


Hi malcolm
I may very well be wrong but i think that monster Moog was used by Wendy
(nee Walter) Carlos on " switched on Bach".
I seem to remember it's shown on the album cover (a copy of which i  sadly
got rid of a long! time ago).
I think it was the 101, or something like that?.

Live long and prosper.

George,8track man,Bath,U.K.





From ben at stuyts.nl  Tue Jan 12 23:11:26 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue, 12 Jan 99 23:11:26 +0100
Subject: Digital DIY synths and DSP stuff... and drums
In-Reply-To: <199901120246.UAA05776@saucer.cc.umr.edu>
References: <199901120246.UAA05776@saucer.cc.umr.edu>
Message-ID: <199901122211.XAA02718@daneel.stuyts.nl>

On Mon, 11 Jan 1999, oncken at umr.edu wrote:

> > (Insert wobbly vertical lines here.)
> > Long time ago I built a full analog drum computer. It was published in
> > Elektuur (of Formant fame), somewhere in the early 1970's. It had a
> > tip-touch panel to select the various drum patterns for each instrument
> > separately. I never got the front panel to work well, so I finally replaced
> > it with a ton of ..
> ..
> ..
> > Is there anybody else out there who built this thing? I can't recall the  
> > exact name. Something like Elekdrum? Elektrom?
> >
>
> Am I understanding you?  A touch panel step sequencer?  Several
> insturments?  16 steps?  Perfect!

No, although that sounds cool. You basically had about 6 preprogrammed  
patterns for the bass drum, 6 other ones for the snare, etc. You chose one (or  
more, you could 'or' them) for each instrument and a meter (3/4 or 4/4 I  
think were the choices), and that was it. You couldn't change the patterns.  
Unless you took out the soldering iron, and started patching the pcb with the  
matrix of 1n4148's on it. B-)

> I for one would love to see this schematic.  Especially the sequencer
> portion.

I don't have it anymore, but it was in early 1970's Elektuur. Back when it  
was a Dutch-only magazine.

> Someone please tell me that they have the schematics and were just about
> to scan them and post them somewhere.  ;)

I'd like to see them again as well.

Best regards,
Ben



From corley.brigman at intel.com  Tue Jan 12 23:13:00 1999
From: corley.brigman at intel.com (Brigman, Corley)
Date: Tue, 12 Jan 1999 14:13:00 -0800
Subject: ODP: Filters
Message-ID: <199901122215.WAA10676@thalia.fm.intel.com>

First, i also am still learning this, so i won't guarantee anything i say to
be 
correct :) but at least i believe it to be correct...it's been a couple
years, 
and i didn't know it well then....

>The
>phase vocoder resolves this problem by tracking the phase of each
>frequency bin in the FFT, and using the change in phase for each window
>to determine the actual frequency. 

fft's don't have to be complex, there is a simplification (i forget what it
is) 
or a certain type of signal that most signals fall into that mean the
complex 
part is all 0 i.e. all real. i'd be interested to hear more about why the
phase 
information is needed. in my (admittedly short) analyses, for an ADDITIVE
synth 
(not fourier-based, but they are similar), the phase is unimportant - the 
waveform is quite different, but the sound is the same. the FFT guarantees 
sample accuracy, of course, so it's a little different. my testing was for 
relatively simple waveforms though - square and saw. if you want to try it,
the 
additive engine at my homepage http://members.xoom.com/elev8 lets you play
with 
this. I tried both shifting all harmonics by, say, 90 degrees, as well as 
shifting different harmonics different amounts. They will probably be
different 
when played polyphonically, maybe, but the basic sound was the same to my
ears. 
This would follow from the above simplification. I believe the
simplification is
for finite, deterministic signals or something like that. looks like it's
time 
to crack open the book again.

> A phase vocoder can analyse a sound,
>and perfectly reconstitute the sound from the analysis material,
>provided that no changes have been made in between analysis and
>resynthesis. 

this is a direct property of the DFT, as i recall, in both discrete and 
continuous forms. as far as I know, though, you don't need a complex FFT for

this relation to be true - can anyone correct me? I throw this stuff out as
much
to learn as anything....phase vocoding is a good way to pitch shift though, 
since it maintains the harmonic relationships of the source signal (at
least, 
IIRC). at least it's an easier way to get right. to do proper phase vocoding
i 
suppose you need an exponential FFT, i think these exist but I wouldn't
swear to
it....you could "fake" it coarsely using a linear FFT of course.

enjoying this discussion,

corley brigman
intel corp.
corley.brigman at intel.com

speaking for me, not for intel.



From ben at stuyts.nl  Tue Jan 12 23:16:01 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue, 12 Jan 99 23:16:01 +0100
Subject: Digital DIY synths?
In-Reply-To: <369AEF67.FBC64AB0@vienna.at>
References: <369AEF67.FBC64AB0@vienna.at>
Message-ID: <199901122216.XAA02723@daneel.stuyts.nl>

On Tue, 12 Jan 1999, Peter Ullrich wrote:

> I started programming a n analog synth emulator with the Analog Devices
> EZKIT-Lite Board (ADSP2181). As my time is very limited I stopped at the
> most difficult part: the filter.

This is what I think would be the heart of the synth. It probably makes or  
breaks the sound. It was the one thing I wanted to concentrate on, so...

> If anyone is interested in the simple code I could thing of putting it
> on my webpage...

Please do! Or email it to me.

I was looking into getting midi into the EZKIT. I found an app note from AD  
about a software UART. That would be nice as it doesn't take up the existing  
serial ports which are already used for RS232 (downloading code) and the audio  
codec. Do you have a midi input on your EZKIT?

> If anyone programmed a VCF-like filter for these board I would be
> interested in it!!!

I don;t have much time at the moment, but I will be looking into it in the  
near future.

Best regards,
Ben



From bjbean at cisco.com  Tue Jan 12 23:28:25 1999
From: bjbean at cisco.com (Bernie Bean)
Date: Tue, 12 Jan 1999 17:28:25 -0500
Subject: Test equipment Web Site
Message-ID: <3.0.32.19990112172821.00730ff0@pentagon.cisco.com>

To All:

I have an associate that has a website related to analog/digital test
equiptment which I have used in some of my projects. Check it out:
www.3dnet.com/mike

Bernie



From ben at stuyts.nl  Tue Jan 12 23:28:55 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Tue, 12 Jan 99 23:28:55 +0100
Subject: Filters
In-Reply-To: <199901120017.QAA13988@smtp.ucsd.edu>
References: <199901120017.QAA13988@smtp.ucsd.edu>
Message-ID: <199901122228.XAA02731@daneel.stuyts.nl>

On Mon, 11 Jan 1999, Ethan Duni wrote:

> anyway, back to the point.. using an FFT based filter, while very cool, is
> probably overkill for doing analog synth modelling (that is what you were
> wanting to do, no?).  Making an FFT filter do modulable resonance and cutoff
> in real time (while really cool) would be a severe pain in the ass,
> especially compared to using "FIR" and "IIR" methods, which will probably be
> just as good for doing analog-synth style filtering (anyone have any
> opinions here?).

I think one of the bigger problems would be that you would like your control  
inputs to change things like the VCF cut-off frequency, amount of resonance,  
etc. Those parameters are not directly accessible with a FIR or IIR filter,  
and the coefficients of the filter terms are not easily calculated from the  
requested input. (Please correct me if I'm wrong though.)

I was wondering if a slightly different approach would work. Why not just  
model the analog circuit of a VCF in real time? Basically it's just R's and  
C's and some op-amps. You could take a SPICE-like approach, but then very much  
simplified.

I have done something like this a long time ago to simulate (in basic,  
duh...) a charging circuit for a stroboscope I built. It had a diode, R and C,  
and was fed using 220 VAC. I wanted to know the charging time of the C, but  
because of the AC input voltage I couldn't figure out how to compute it  
directly. So I just stepped (in 1 ms increments or so) through time, and  
calculated the currents and voltages. Worked great, and it is very easy to  
follow!

Having the power of a DSP at your hands, this could be easily done (I  
suppose) for a 44 kHz sampling rate.

> incidentally, i have a big design project coming up in the next couple of
> years for my degree.  what i've been thinking of doing is sort of along
> these lines.. I'm calling it a convolution-synth for lack of a better term;
[snip]

That was an interesting explanation you gave. Please keep us informed about  
your progress.

Best regards,
Ben



From corley.brigman at intel.com  Tue Jan 12 23:34:00 1999
From: corley.brigman at intel.com (Brigman, Corley)
Date: Tue, 12 Jan 1999 14:34:00 -0800
Subject: ODP: Filters
Message-ID: <199901122235.WAA14264@thalia.fm.intel.com>

<harmonic distortion>
ok, this makes sense, but isn't totally easy to avoid, since you don't 
really know the frequency content of the bin, and must redistribute its 
energy among multiple bins. dividing it evenly may not be correct. suppose 
we have a 512 element FFT, and a sine wave at 440 Hz. Bin 6 contains the 
info for ~430 to ~516. all the energy for this waveform shows up in this 
bin? at least that's the general idea, since it's basically an impulse it 
probably doesn't actually work that way. anyway to pitch shift up would 
distributing the energy equally between the bins that correspond to ~860 to 
~1032 (4 or 5 bins likely). However, only 1 of these bins should actually 
have any energy in it, the one at 880. Or am I doing this wrong? Even so 
I'm sure there are standard ways to deal with this, i guess this is where 
you need the phase information? to give additional info about the frequency 
content of the bin? i'm really curious about this, now that I am thinking 
about it...i know the frequencies when I do it additive but this is a 
different creature....

>i'd think an ifft would be better for more complicated stuff.. you'd
>acutally need more than one multiplication per harmonic for the filter; the
>frequency response of the filter could be achieved this way, but with the
>FFT method you are using an array of complex numbers that represents  both
>the frequency and phase response of the filter in question (although if you
>are looking to implement a perfectly phase-distortion-free filter, this
>isn't a problem :])

in my very limited empirical analysis :), phase doesn't matter that much
when 
you deal with additive. see my other message for a possible explanation. or 
maybe my sample was too small (very easy, i only used variations on 2
waveforms,
single-note)....

>-uh-oh, we're dangerously close to wavelet analysis here :]
>and isn't the k5000's formant filter FFT-based (or rather iFFT; i'm not
sure
>the data has ever left the frequency domain at that point)?

that's kind of the idea, although I have only conceptual knowledge of
wavelets, 
no experience or even theory. the k5000's filter is described as a 128-band 
graphic eq, which afaik can be modeled as a 128-point FFT, so it wouldn't 
surprise me....and also AFAIK even though the k5000 DOES have some sampled 
transients, i don't think these go through the formant filter, so it sounds
like
it probably is just an IFFT...128 points wouldn't be so bad after all...

enough for now. i'll break out my dsp book tonight and after a couple months
to 
make sense of it :) i'll correct all the mistakes i'm sure i made above....

corley brigman
intel corp.
corley.brigman at intel.com

speaking for me, not for intel.



From eduni at ucsd.edu  Wed Jan 13 02:39:21 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Tue, 12 Jan 1999 17:39:21 -0800 (PST)
Subject: ODP: Filters
Message-ID: <199901130139.RAA00927@smtp.ucsd.edu>


>fft's don't have to be complex, there is a simplification (i forget what it
>is) 
>or a certain type of signal that most signals fall into that mean the
>complex 
>part is all 0 i.e. all real. 

-ah; i believe i know what you are referring to.  There are some confusing
semantics surrounding this area.. in the general case, Fourier transforms
work on complex-valued inputs (time domain functions).  However, much of the
time we are only concerned with real signals (imaginary part is zero), in
which case the output of the transform is symmetric, so you can stop short
of calculating half of it.  however, the OUTPUT of a fourier transform
always conatins both the phase and amplitude information, usually in the
form of a complex number (i believe there are some other ways of notating
that come out differently).  perhaps this is causing some confusion.

>i'd be interested to hear more about why the
>phase 
>information is needed. in my (admittedly short) analyses, for an ADDITIVE
>synth 
>(not fourier-based, but they are similar), the phase is unimportant - the 
>waveform is quite different, but the sound is the same. 

-Ah! one has to be careful here.  It is true that if you listen to a given
waveform and then you stop and shift the phases of a bunch of the harmonics
in it and listen to that, they won't sound different.  But, if you create a
sound such that one or more of the harmonics' phase changes throughout the
sound you should be able to distinguish it fromt he case where the phases do
not change (for instance, what if one of the harmonics was to be continually
shifted forward in phase throughout the duration of the sound; this would be
identical to throwing the harmonic out of tune (!)).. it also is probably
more relevant in the case of filters; a filter will shift each frequency a
different amount (generally), which can be really significant in the case of
feeding the filter's output back.. 

>the FFT guarantees 
>sample accuracy, of course, so it's a little different. my testing was for 
>relatively simple waveforms though - square and saw. if you want to try it,
>the 
>additive engine at my homepage http://members.xoom.com/elev8 lets you play
>with 
>this. I tried both shifting all harmonics by, say, 90 degrees, as well as 
>shifting different harmonics different amounts. They will probably be
>different 
>when played polyphonically, maybe, but the basic sound was the same to my
>ears.
 
-i think what would happen polyphonically is that you'd get unexpected
cancellations in the end product.  another place phase is importnat is in
stereo; phase differences between sounds is one of the big ques that your
ears use to locate objects spatially (think about when you hear, say, a
truck that is 10 feet in front of you and 5 feet to your left.  the sound
won't really be any louder in one ear than the other, but if you close your
eyes you'll still be able to spatially locate the source of the sound; it's
the phase difference incurred by the path length difference).  another thing
to do is to shift some of the phases of the harmonics on one side of a
stereo pair; same signals, different phases= stereo!

>this is a direct property of the DFT, as i recall, in both discrete and 
>continuous forms. as far as I know, though, you don't need a complex FFT for
>
>this relation to be true - can anyone correct me? I throw this stuff out as
>much
>to learn as anything....phase vocoding is a good way to pitch shift though, 
>since it maintains the harmonic relationships of the source signal (at
>least, 
>IIRC). at least it's an easier way to get right. to do proper phase vocoding
>i 
>suppose you need an exponential FFT, i think these exist but I wouldn't
>swear to
>it....you could "fake" it coarsely using a linear FFT of course.

-i had the impression that FFT's were linear beasts; i was doing some
readings on wavelets (http://www.amara.com/current/wavelet.html - great
page) wherein one of the touted advantages of wavelet analysis over FFT
analysis was the wavelet transform's nonlinear frequency resolution.  though
it doesn't seem that it would be too difficult to define any operations done
on a frequency-domain FFT signal to be nonlinear with frequency (i believe
this is all that's done in the pitch-scaling algorithms used in various
products.. check this page out for some more info:
http://www.prosoniq.com/time_pitch_faq.html ).. 

as long as i'm recommending literature, let me throw out a book that i
thought was a great intro into the world of FFTs: 

The FFT: Fundamentals and Concepts by Ramirez (i think).  it seems it was
actually written for tektronix scope customers to enlighten them about what
those FFT plug-in boards for the scopes would do, but it's pretty general.
doesn't go into too much mathematical depth or complexity, but it clearly
illustrates all of the ideas that one has to grasp to understand and use
fft's (as well as fourier series and continuous transforms).  it also has
some neat introductory information on convolution and correlation and their
relations to the FFT.

Ethan




From thudson at cygnus.com  Wed Jan 13 02:49:34 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Tue, 12 Jan 1999 20:49:34 -0500
Subject: Heaviness (was Re: Day job)
References: <yam7681.1225.118991008@mail.mindspring.com> <369C3874.6B5D1579@seanet.com>
Message-ID: <369BFBAE.BF30E308@cygnus.com>

Sean Costello wrote:
> A few benchmarks for you, in the heaviness realm:
> 
[snip]

I'll add some more:

Jimi Hendrix' Machine Gun, from Band of Gypsies.

Death and Transfiguration, Strauss. Tone Poem about an 
existentialist artist on his deathbed... heavy and pretty.

Gang of Four's Antrax. I love feedback...

Heaviest oscillator circuit:
Stratocaster thru MXR dynacomp thru fuzz face thru 100 watt
Marshall. Set everything to ten and walk around the room.
Tap on back of neck. Change angles of guitar when it settles
into a single pitch. Bang on floor.

Thomas



From vco at mindspring.com  Wed Jan 13 02:51:24 1999
From: vco at mindspring.com (tomg)
Date: Tue, 12 Jan 1999 20:51:24 -0500
Subject: Day job
In-Reply-To: <002501be3e6a$a2352540$f340d4d4@oemcomputer>
Message-ID: <yam7681.1225.118991008@mail.mindspring.com>

ok...

I started life cloning stuff. I copied my first fuzz-tone
at 12. I've been a repair tech for just about everything. 
I spent the last 3 years running my own repair shop, before 
that I worked as a service manager for several large corps. 
including RS.

I got rid of the shop and I've been building synthesizers 
for the last 2 years. I wanted to have a few things I could
not buy. Most of the stuff I have came to me broken, I have
the feeling it's the only reason I have been able to find
anything at all.

I'm a guitar player first.I got on keys late, pretty much had 
to become a keyboard tech first before I realized how cool the 
whole midi thing was for a roaming guitarist. Once into it, it 
has taken over a large part of my life. I have gone though a 
ton of stuff and have little room left for more.

I have always been in a band or playing with somebody. I 
am now in production of quote "The heaviest music ever 
recorded." the source was a true fan...:-) I hope to have 
a CD or 2 ready soon.

I have a great little project studio. I can go from open mic 
to multi track-HD to CD and do my own short run Cd2Cd 
duplication w/labels.

These days I record music/noise and build synthesizers. Lately 
I've been selling a few rodents...:-)

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From moxie at idonex.se  Wed Jan 13 03:30:10 1999
From: moxie at idonex.se (Johan Gustavsson)
Date: Wed, 13 Jan 1999 03:30:10 +0100 (MET)
Subject: my ssm2164 quad VCO again
In-Reply-To: <2BF6F749A4A3D11185AD00A0C94CF67A4D6880@demon> (message from
	Roman Sowa on Mon, 11 Jan 1999 18:58:41 +0100)
Message-ID: <199901130230.DAA03762@jolt.idonex.se>

> Anyway I'd be thankful for any comments about this website.
> BTW I'm not so good at this as some of you are, so don't expect
> to find any Java, frames, cool graphics etc.
> Just plain text, and schemos

Well, Y'know, what I want is schemos and text. If there is something I
hate, it's animated GIFs, javashockwaveimplosionenhanceframed sites
that are so busy being cool that it is impossible to find stuff in
it. Or even better, that is made only for one platform ("This site
must be viewed with MicroBlows Exploder").

In other words, methinks you are a lot better for *not* using all that
fancy-but-meaningless crap. More power to you! And that's even
*before* looking at the actual site :-)

*click, click* Ah...Looks nice. If I get hold of a 2164 or two, I'd
definitely be interested in that envelope generator...Keep up the good
works! Oh, and there seems to be some sort of cgi script thingie that
keeps pushing me back to the schematics page if i try to go "back"
from it. Don't do that. It's evil, and will make your palms go all
hairy.

Ah, yes, envgenerators...My Maxx modular is almost up and running! The
PS isn't quite in place yet, but we have four modules all built (a
dual LFO, a dual VCA, one VCO-5 and a dual KLM filter) and another
bunch quite in the works (APM module, SSH, audio mixer, cv mixer,
tranny ladder filter, bandpass filter, dual VCO-2...), all put behind
psychedelically/graffittish panels in an old suitcase...Definitely
going for a keyboard magazine "keyboard of the month" photo on this
one! :-) Anyone thinks it is an odd choice of modules to start off
with? Well, we're learning as we go along, so we started out with
those that looked simple :-)

I'm quite excited - I mean, I've been talking about building a modular
for about two years now, and suddenly it is happening! That's cool :-)

Ah, well, time to stop gushing. Soon we'll start plugging things
together and try to tune everything, and I guess I'll come back to
reality by then :-)
/Moxie (The quite easily excited, these days)




From ijfritz at earthlink.net  Wed Jan 13 03:44:44 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Tue, 12 Jan 1999 19:44:44 -0700
Subject: Filters
References: <199901120017.QAA13988@smtp.ucsd.edu> <199901122228.XAA02731@daneel.stuyts.nl>
Message-ID: <369C089C.BF64A477@earthlink.net>


Ben Stuyts wrote:

> I think one of the bigger problems would be that you would like your control
> inputs to change things like the VCF cut-off frequency, amount of resonance,
> etc. Those parameters are not directly accessible with a FIR or IIR filter,
> and the coefficients of the filter terms are not easily calculated from the
> requested input. (Please correct me if I'm wrong though.)
> 
> I was wondering if a slightly different approach would work. Why not just
> model the analog circuit of a VCF in real time? Basically it's just R's and
> C's and some op-amps. You could take a SPICE-like approach, but then very much
> simplified.


Hal Chamberlin's book shows how to do this. First, you make a diagram of
the (analog) filter's topology, using integrators, amplifiers and
summers.  Then for the digital implementation you just need to realize
that a digital integrator is implemented by summing an input signal with
a delayed version of itself: y(n) = x(n) + y(n-1). A state variable
filter requires five additions and three multiplications per time step.
Six lines of BASIC.

  Ian



From eduni at ucsd.edu  Wed Jan 13 03:59:49 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Tue, 12 Jan 1999 18:59:49 -0800 (PST)
Subject: ODP: Filters
Message-ID: <199901130259.SAA04915@smtp.ucsd.edu>

At 02:34 PM 1/12/99 -0800, you wrote:
>the k5000's filter is described as a 128-band 
>graphic eq, which afaik can be modeled as a 128-point FFT, so it wouldn't 
>surprise me....and also AFAIK even though the k5000 DOES have some sampled 
>transients
-more than transients; it's a fully functional rompler.  actually, if you
use sounddiver with it, you can supposedly input .wav files and analyze them
into additive patches for the thing.  never tried it, as i don't have a
k5000 (my friend does), but it sounds really neato.. imagine modulating the
even harmonics in a sample with the modwheel while aftertouch adjusts their
phases relations.. neat.. 

gotta get one of those things and find out about it.. 

Ethan




From ka4hjh at gte.net  Wed Jan 13 04:49:02 1999
From: ka4hjh at gte.net (KA4HJH)
Date: Tue, 12 Jan 1999 22:49:02 -0500
Subject: Sequencer microprocessors
In-Reply-To: <00d501be3e3e$5a5580c0$eed26ccb@ppp.ozemail.com.au>
Message-ID: <v04011701b2c1c719efbe@[208.252.40.19]>

>What sort of processor would be best for such a design? Keeping in
>mind I want to add more recent features found on modern instruments
>like realtime midi control of the sounds, and leaving the sequencer
>running while changing from play to write mode (like the 606).....
>
>I haven't done much on uP's, apat from a PLC and one of the simple
>motorola devices....

Any decent 8 bit processor will do. PIC's, HCO5's (I love Motorola), even
(shudder) Intel. You want to use something that either has built-in ERPOM
or EEPROM, or start off with a single-board controller that sockets for
external non-volatile memory (lots of those around these days--some even
have I/O for LCD displays and what-not built-in). There's MIDI code for the
6805 at the Midwest Analog Products page.

Terry Bowman, KA4HJH
"The Mac Doctor"



From costello at seanet.com  Wed Jan 13 06:54:11 1999
From: costello at seanet.com (Sean Costello)
Date: Tue, 12 Jan 1999 21:54:11 -0800
Subject: Filters
References: <199901120017.QAA13988@smtp.ucsd.edu> <199901122228.XAA02731@daneel.stuyts.nl> <369C089C.BF64A477@earthlink.net>
Message-ID: <369C3503.95F30E30@seanet.com>

Ian Fritz wrote:
> 
> Hal Chamberlin's book shows how to do this. First, you make a diagram of
> the (analog) filter's topology, using integrators, amplifiers and
> summers.  Then for the digital implementation you just need to realize
> that a digital integrator is implemented by summing an input signal with
> a delayed version of itself: y(n) = x(n) + y(n-1). A state variable
> filter requires five additions and three multiplications per time step.
> Six lines of BASIC.

The topology that Chamberlin gives for a state-variable filter is
considered to be pretty decent in the literature - Jon Dattoro wrote
about it recently in the JAES, and states that it may be the filter
design used in the Kurzweil synths.  We are learning about filters in my
computer music class right now, but without going into detail about the
topologies - not enough time (sigh).  

There have been several attempts to bring the Moog filter into the
digital realm, mostly based on the work of Timothy Stilson at CCRMA at
Stanford (check out
http://www-ccrma.stanford.edu/~stilti/papers/Welcome.html for his paper
on the subject).  Josep Comajuncosas ported the Stilson design over into
a Csound orchestra, and Hans Mikelson coded it into a Csound unit
generator.  It sounds very good, although not as dirty as a real Moog -
closer to a Roland SH-101 filter. Unfortunately, the Csound moogvcf unit
generator tends to blow up, at least when I use it (i.e. the output
suddenly jumps from an acceptable amplitude like 16000 or so, to values
like 50389823798379, infinity, and so on), so it may not be the best
example of how to code such a filter.  

Off I go to read F. Richard Moore's Elements of Computer Music, and/or
fall asleep.

Sean Costello



From costello at seanet.com  Wed Jan 13 07:08:52 1999
From: costello at seanet.com (Sean Costello)
Date: Tue, 12 Jan 1999 22:08:52 -0800
Subject: Heaviness (was Re: Day job)
References: <yam7681.1225.118991008@mail.mindspring.com>
Message-ID: <369C3874.6B5D1579@seanet.com>

tomg wrote:

> I have always been in a band or playing with somebody. I
> am now in production of quote "The heaviest music ever
> recorded." 

A few benchmarks for you, in the heaviness realm:

1) The song "Holy Mountain" by Sleep.  Black Sabbath on half speed.
2) The album "Eggnog" by the Melvins.  Black Sabbath on eighth speed;
or, Slayer on the edge of a black hole.  Most older Melvins albums
should be considered as well.
3) Godflesh's self-titled first album.
4) Songs about Fucking, by Big Black.  Crisper, but still quite heavy.
5) "Jimi" by the Butthole Surfers
6) Cluster '71, by Cluster.  Heavy like staring into the void.
7) "Ventolin" by Aphex Twin (well, heavy in terms of psychological
destruction, as well as physical destruction to your ears for listening
to it too much)

Not too aware of the black metal bands.  Admittedly heavy stuff, but it
sounds too much like Cookie Monster singing about Satan.  The book
"Lords of Chaos" is a great read, however.

Apologies for the off-topicness of the thread, but I spent far too much
of my life thinking about "heavy" to pass this up.  Will hopefully post
useful FFT-related stuff as soon as I understand it better.

Heaviest circuit ever: Univox Super-Fuzz.  Full-wave rectifier provides
ring-modulation distortion on chords, germanium diodes provide clipping
on that, and a notch filter makes it sound like a thousand amps blowing
up.  If someone has a heavier circuit, please post it.

Sean Costello

P.S.  Heaviness prototypes: "Summertime Blues" by Blue Cheer, and pretty
much everything Black Sabbath ever touched, but especially the album
Masters of Reality.



From jdm at synthcom.com  Wed Jan 13 08:30:08 1999
From: jdm at synthcom.com (J.D.McEachin)
Date: Tue, 12 Jan 1999 23:30:08 -0800
Subject: Heaviness (was Re: Day job)
In-Reply-To: <369C3874.6B5D1579@seanet.com>
References: <yam7681.1225.118991008@mail.mindspring.com>
Message-ID: <3.0.5.32.19990112233008.007a7850@synthcom.com>

At 10:08 PM 1/12/99 -0800, Sean Costello wrote:

>4) Songs about Fucking, by Big Black.  Crisper, but still quite heavy.

>Apologies for the off-topicness of the thread, 

Here's your on-topic out - Songs about Fucking has a Kraftwerk cover, The
Model, pretty hilarious as I remember - bass of doom, grindy guitar,
booming Linndrum, and distorto vox.

JDM

PS Most beautiful Kwerk cover - Neon Lights by Love Tractor...



Anyone trying to attach a standard of truthfulness to a politician's
behavior is naive and worthy of contempt.



From Zsolt.Homlokos at rz.ruhr-uni-bochum.de  Wed Jan 13 10:46:47 1999
From: Zsolt.Homlokos at rz.ruhr-uni-bochum.de (Zsolt Homlokos)
Date: Wed, 13 Jan 1999 10:46:47 +0100
Subject: MODULARS!!??
References: <199901120017.QAA13988@smtp.ucsd.edu> <199901122228.XAA02731@daneel.stuyts.nl>
Message-ID: <369C6B87.8CE21599@rz.ruhr-uni-bochum.de>

Hello,
this is no DIY question but i think you are the people who know the modulars best.

the thing is that i am desperately looking for an analogue modular
and of course i am lookiing for a special one,
and i dont know whether it should be a vintage or a new modular
what is important to me is a great sound and the flexibility to create a vast
range
of different sounds.1 VCO-1VCF-1VCA module wouldnt be that improvement to me , i
think.
i already asked the people of AH, and i realized that everybody has a different
opinion......
one says ARP 2600, the other Moog,Serge and the new styled gear like MOTM
and Doepfer
so if somebody could give some good advice then i probably could stop thinking
of these machines for at least 5 minutes
thanks and have a nice day
Zsolt




From buchi at dci.de  Wed Jan 13 11:18:34 1999
From: buchi at dci.de (Michael Buchstaller)
Date: Wed, 13 Jan 1999 10:18:34 GMT
Subject: No PCB layout software!
In-Reply-To: <09DB74475204D1119C8200805F19D00302E20BDD@aeromsg1.ball.com>
References: <09DB74475204D1119C8200805F19D00302E20BDD@aeromsg1.ball.com>
Message-ID: <369d72ba.70207485@mail.dci.de>

>Cost: $50 US.  The Eagle stuff looked good to, but I need boards larger than
>X by Y.

in Eagle, you can set the PCB board size to anything you want, even
irregular (non-rectangular) shapes are possible !


-Michael Buchstaller



From vco at mindspring.com  Wed Jan 13 11:25:50 1999
From: vco at mindspring.com (tomg)
Date: Wed, 13 Jan 1999 05:25:50 -0500
Subject: Heaviness (was Re: Day job)
In-Reply-To: <369C3874.6B5D1579@seanet.com>
Message-ID: <yam7682.2527.119057352@mail.mindspring.com>

On 13-Jan-99, Sean Costello wrote:
>tomg wrote:

>> I have always been in a band or playing with somebody. I
>> am now in production of quote "The heaviest music ever
>> recorded." 

>A few benchmarks for you, in the heaviness realm:

There are others but when it comes to heavy Iommi's riffs
RULE! 

I didn't mean to sound like I was bragging, I really do know
better. It's just something someone said, I thought it was 
funny. Pretty dammed heavy thought. The first time my wife
heard any of it she screwed up her face and said "It sounds 
like a wall of noise to me." A lot of people are really
going to hate this crap...probibly my wife too. She likes the
stuff that sounds like songs (humph)...but I like to hurt things 
and record it. A little brain damage now and then is a good
thing...%:-)

Anyway if you think that I think that I am recording the quote 
"heaviest music ever recorded.".....the answer is No! But it's
cool that someone does.

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From martin.czech at intermetall.de  Wed Jan 13 11:30:25 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 13 Jan 1999 11:30:25 +0100 (MET)
Subject: MODULARS!!??
Message-ID: <199901131030.LAA12007@window.intermetall.de>


> the thing is that i am desperately looking for an analogue modular
> and of course i am lookiing for a special one,
> and i dont know whether it should be a vintage or a new modular
> what is important to me is a great sound and the flexibility to create a vast
 
SNIP

So you want to buy a system, that may be cheaper than diy.

The problem is where to find a vintage system, and what you can pay
for it.  The new breed of remakes that is now on the market looks quite
good.  I'd try a Nord Modular (softwrae , I know, but nervertheless)
, or a Technosaurus. Doepfer seems to be a bit too cheap to me, little
frontplates, tiny knobs, no good jacks.

m.c.




From rsowa at WizjaTV.pl  Wed Jan 13 11:59:42 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Wed, 13 Jan 1999 11:59:42 +0100
Subject: PCB layout, Filters, SEQ uP
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D688F@demon>

Hi all,
recently I've seen too much posts from me on the list, so here is
a compilation of my comments

First of, thank you all for nice words about my website
www.multimania.com/romcio
Now I'm more convinced that I'm doing it the right way.

PSBs - wirewrap:
Maybe I'll put a photo of my first VCO prototype on the web.
Then you'll see what wirewrap means to me - no board and works!

according to Jorgen's post:
> 1. Most software cost money. A general drawing program is useful for so
many
> other things, that you want to have it in any case.
True, they cost money, but when I played with evaluation version of Corel
Draw
I uninstaled it after two hours. Much worse for me to use than any PCB
software.

> 2. When I design the board manually, I can do sneaky things like shaving
off
> portions of pads to make room for a trace that would not otherwise fit.
The boards I
> have seen other people do are not as compact and have more wire links than
mine,
> that's a fact.
That's becouse you haven't seen mine ;-). But seriously, you can always
define other than circle pad type.

> 3. I can design the schematics symbols to look exactly like I want them. I
have
> emulated the style in Elektor magazine, for nostalgic reasons.
PCB software can do that

> 4. I can have beautiful full color parts placement diagrams. My parts
symbols look
> almost exactly like the real parts.
You make PCB or painting for art gallery?

> 5. It is good brain gymnastics to keep the routing in the head.
Occasionally I make
> a mistake, but it is necessary to build a prototype anyway. Board layout
errors are
> usually easy to correct on the prototype.
Yes, I sometimes get up from designing PCB completely exhausted. And they
always contain mistakes anyway. But with PCB software you can draw
the schematic and it will check if it matches PCB you've drawn.

Filters:
I made some time back a Windoze software which turns your mouse
drawn FIR frequency response into coefficients.
And btw uploads them to my DSP board or writes to file.
Anyone interested? Should I bother making english version? Free!

Tuning FIR filters:
Make large FIR, and sample its coeffs like you do with wavetable.
Then you get low freq filter with narrow spaced samples
and high freq filter with wide spaced coefficient samples.
Somehow I feel this description wasn't clear...

Sequencer microprocessors:
It might be overkill, but when PIC16F84 is running out of resources
I like to put 80C188 in action. Then I'm limited only but imagination.
Although it requires some extra ICs.
btw there is new PIC coming out soon. It's flash version of 16C7x
or something like that. At last!
And Hitachi makes nice uPs. 128kB of flash, free C, about 20$
don't remember part name tho...

Roman



From Ullrich at kapsch.net  Wed Jan 13 12:16:18 1999
From: Ullrich at kapsch.net (Ullrich at kapsch.net)
Date: Wed, 13 Jan 1999 12:16:18 +0100
Subject: AW: Digital DIY synths?
Message-ID: <13673333E22DD211B57F0000F8CB39FFABAF6E@tick.kapsch.co.at>

	Hallo Ben!

	>> If anyone is interested in the simple code I could thing of putting it
	>> on my webpage...
	>
	>Please do! Or email it to me.

	I will have a look for it on my harddisk at home and will send it to you.
	Maybe I can make a simple download-link on my homepage.

	>I was looking into getting midi into the EZKIT. I found an app note from AD  
	>about a software UART. That would be nice as it doesn't take up the existing  
	>serial ports which are already used for RS232 (downloading code) and the audio  
	>codec. Do you have a midi input on your EZKIT?

	I want to build an 8051 processor around the EZKIT-LITE that connect through the IDMA-interface. The schematics are ready for quite a long time but I had no chance to test it as my time is very limited.

	>> If anyone programmed a VCF-like filter for these board I would be
	>> interested in it!!!

	>I don;t have much time at the moment, but I will be looking into it in the  
	>near future.

	If you have anything I would be happy if you could send it to me!

	Ciao
	Peter

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/                                                                  




From LesPaul52 at aol.com  Wed Jan 13 12:47:15 1999
From: LesPaul52 at aol.com (LesPaul52 at aol.com)
Date: Wed, 13 Jan 1999 06:47:15 EST
Subject: Digital poly scan keyboard
Message-ID: <3c481e7c.369c87c3@aol.com>

To whom might know!

I need some help with a polyphonic keyboard scanner, It is gonna use the 8:1
mux idea but I don't know if It scans off resistors or diodes, and i don't
know how to address them using 6 bits, if anybody can be a help with this, it
will be greatly appreciated,

Thanks
Tom Howell
LesPaul52 at aol.com
ICQ#13710243



From jorgen.bergfors at idg.se  Wed Jan 13 13:23:11 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Wed, 13 Jan 1999 13:23:11 +0100
Subject: PCB layout, Filters, SEQ uP
Message-ID: <TFSLDNHB@idg.se>

>> 4. I can have beautiful full color parts placement diagrams. My parts
symbols look
>> almost exactly like the real parts.

>You make PCB or painting for art gallery?

I'm only in it for the art. Music is art and I want my synthesizer to be a piece of art too. I have seen too many homebuilt synths that look like piles of junk. Mine is going to look as good as commercial synths. No, make that "better than commercial synths". This is a hobby and to me there is no joy in making it if it doesn't look good. And that holds for internal parts like circuit boards too.

/Jorgen




From Juergen.Haible at nbgm.siemens.de  Wed Jan 13 13:33:18 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 13 Jan 1999 13:33:18 +0100
Subject: AW: MODULARS!!??
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582011C5BE6@nbgm336a.nbgm.siemens.de>

This is not really Modular, but if you're tired of the usual
"1 VCO-1VCF-1VCA" stuff - have you considered an EMS VCS-3 ?

As for the new Modulars, stay away from low budget stuff.
Invest in quality rather than quantity, and expand in the future.

JH.


	>Hello,
	>this is no DIY question but i think you are the people who know the
modulars best.
	>
	>the thing is that i am desperately looking for an analogue modular
	>and of course i am lookiing for a special one,
	>and i dont know whether it should be a vintage or a new modular
	<what is important to me is a great sound and the flexibility to
create a vast
	>range
	>of different sounds.1 VCO-1VCF-1VCA module wouldnt be that
improvement to me , i
	>think.
	>i already asked the people of AH, and i realized that everybody has
a different
	>opinion......
	>one says ARP 2600, the other Moog,Serge and the new styled gear
like MOTM
	>and Doepfer
	>so if somebody could give some good advice then i probably could
stop thinking
	>of these machines for at least 5 minutes
	>thanks and have a nice day
	>Zsolt




From julian at flashmail.com  Wed Jan 13 13:43:05 1999
From: julian at flashmail.com (Julian)
Date: Wed, 13 Jan 1999 23:43:05 +1100
Subject: Synar(star instruments0
References: <Pine.OSF.3.95.990112154243.23089C-100000@bulldog.unca.edu>
Message-ID: <369C94D9.3878F3C5@flashmail.com>

Chad Ashley Pry wrote:



>   I'm trying to get ahold of schematics and a manual for the star

> instruments Synare9 the one that looks like a flying saucer)



I've got a synare3 that I've been meaning to reverse engineer for about

2 years now!

:)


I bought 2 from from a "junk" store, AU$5 apiece. They were full of mud.
one works, the other is still "sleeping". With the working one, all I
had to do was clean it up a bit, put a new plug on the power cord and
replace a physically damaged pot, and it worked. the other one seems to
be a little bit sicker than that.



looking inside quickly now: has a 4093 (CMOS hex inverter????) and 5

LM3080's plus 19 transistors, then a pile of caps/resistors. 

it uses a small speaker as the pickup to sense when it's been hit.
Mine have mains power supplles built in, but by the looks of them, they
appear to be more recent additions, or a very late design afterthought.



It's a pretty fun unit, basically a 2 osc normalised synth with vcf and

vca, kind of novel in that osc2 can control filter cutoff. Nothing too
fancy, but you hit it on the top and then wiggle the knobs madly to get
wibbly whooshing noises. :)



sections are as follows:



Oscillator 1

	tune

	switch (off, noise, osc1)



Oscillator 2

	tune

	switch (off, slo, osc2)



Filter

	tune

	osc2

	sweep

	res

	decay



Amplifier

	decay

	vol


Would anyone on the list be interested, when I eventually (soon?!?!) get
this thing reverse engineered, to see how it's built? or is there the
schematic for this thing already on the web? (I'd hate to do all this
tedious reverse engineering if it's not necessary) But say if you're
interested, if there's a bit of interest that will definately hurry me
up.

Also, if anyone knows what they originally looked like (photos?), I'd
like to know what knobs they had (mine have bare shafts) It'd be nice to
get them both back to mint condition some day.


> Please let me

> know if you can help me out. thanks.

> 

well, it's not quite a synare9. I've never seen a synare9 in my life but
I'm guessing it's pretty close. It's even flying saucer shaped. how
about you build 2 of them, and multiply the outs. after all,
synare3*synare3=synaresynare9 !!!!!!
ha. haha. ha.ha.ha.ha.ha.ha.ha.ha. *slaps self on forehead*


julian



From Ullrich at kapsch.net  Wed Jan 13 14:35:49 1999
From: Ullrich at kapsch.net (Ullrich at kapsch.net)
Date: Wed, 13 Jan 1999 14:35:49 +0100
Subject: AW: Digital poly scan keyboard
Message-ID: <13673333E22DD211B57F0000F8CB39FFABAF7B@tick.kapsch.co.at>

	Hallo!

	>I need some help with a polyphonic keyboard scanner, It is gonna use the 8:1
	>mux idea but I don't know if It scans off resistors or diodes, and i don't
	>know how to address them using 6 bits, if anybody can be a help with this, it
	>will be greatly appreciated,

	If you want I could scan the schematics of my Crumar masterkeyboard.
	I also have the Intelhex-file for the 8751 controller that does the decoding.
	It outputs polyphonic midi-data on midi channel 1 so you could directly control a synth with it.

	The keyboard part is the same as in the Crumar BitOne keyboards as far as I know.

	Ciao
	Peter

        \|/
       (o o)
--oOOO--(_)--OOOo------------------------------------------------------
                   Ing. Peter Ullrich         mailto:ullrich at kapsch.net
                   Homepage: http://come.to/ullrich    or the full link
                   http://www.geocities.com/SiliconValley/Heights/3586/
                   Hardware & Software Developer /  Electronic Musician
   .oooO           KAPSCH AG / SGB2                    Vienna / Austria
   (   )   Oooo.            Traffic Control and Transmission Technology
----\ (----(   )-------------------------------------------------------
     \_)    ) /
           (_/                                                                  




From mmcintos at ball.com  Wed Jan 13 17:08:22 1999
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Wed, 13 Jan 1999 09:08:22 -0700
Subject: PCB layout software!
Message-ID: <09DB74475204D1119C8200805F19D00302E20BDE@aeromsg1.ball.com>

Sorry this is long.   :-/

Well,  The online information on the FREEWARE version on EAGLE Layout Editor
at CadSoft (http://www.CadsoftUSA.com/) is as follows:

<	The useable board area is limited to 100 x 80 mm (4 x 3.2 inches). 
<	Only two signal layers can be used (Top and Bottom). 
<	The schematic editor can only create one sheet. 
<	Support is only available via email or through our forum (no fax or
phone support). 
<	Use is limited to non-profit applications or evaluation purposes. 

And here is some information on the DEMO version (which is different than
the FREEWARE version):

<	The demo version which we have been offering so far (and which is
still available)
<	allows you to handle boards and schematics without the
aforementioned limitations.
<	So if you want to see how EAGLE can handle large boards, you can use
the demo
<	version to do so. However, the demo version cannot save files ....

OK, I confess, I actually have not tried to set up a board larger than 4" X
3.2" (101.6 mm X 81.28 mm) with the FREEWARE version.  Also, I have not
downloaded and tried to actually save a file with the DEMO version.

To register the FREEWARE version for commercial applications cost $49 US.
The Standard Edition costs $199 US per module and the Professional Edition
cost $399 US per module (layout editor module, schematic editor module and
autorouter module)

It seems to be really good software, but to get to unlimited board sizes I
have to pay allot of money.  I only need the power of the FREEWARE version
but I need the board size of the Professional Edition.  So, that's why I
chose "PCB Development Tools".  The $49 version of this software has
limitations too: 15 X 15 inch (380 x 380 mm)  board size, 1500 lines and
1000 pads.

I truly don't know because I am new at this but, is 1500 lines and 1000 pads
enough?

malcolm

> -----Original Message-----
> From:	buchi at dci.de [SMTP:buchi at dci.de]
> Sent:	Wednesday, January 13, 1999 3:19 AM
	To:	synth-diy at mailhost.bpa.nl 
> Subject:	Re: No PCB layout software!
> 
> >Cost: $50 US.  The Eagle stuff looked good to, but I need boards larger
> than
> >X by Y.
> 
> in Eagle, you can set the PCB board size to anything you want, even
> irregular (non-rectangular) shapes are possible !
> 
> 
> -Michael Buchstaller



From dbalvage at ptdcs2.ra.intel.com  Wed Jan 13 17:18:09 1999
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Wed, 13 Jan 1999 08:18:09 -0800
Subject: Synar(star instruments0
References: <Pine.OSF.3.95.990112154243.23089C-100000@bulldog.unca.edu> <369C94D9.3878F3C5@flashmail.com>
Message-ID: <369CC741.167E@ptdcs2.intel.com>

Hey -

I have what I believe to be the "Synare 1" so to speak. (it just says

Synare by Star Industries on the top.) It's not shaped like a UFO at 

all, but like a cutout suitcase(!) It's kinda big - it has 4 "position 

sensitive" pads on it, and it's a 1 osc beast w saw/square/PWM

filter w/ cutoff/rez, ring mod w/ mod osc, env gen w/delay and

vca. Oh yeah, white AND pink noise, and an LFO with square/tri out.

Anyone ever seen one of these?? Or a <snicker> schematic??


				- Duane
-- 
   "That boy's got a mouth like a cannon ... Always shootin' it off..."
                                
                             - Foghorn Leghorn
                      ________________________________
                     / o o oo              o ooo o   /\
       -------------/ ////  Duane R. Balvage   //// / /---------
                   /    _________________________  / /
                  / // / // /// // /// // /// / / / /
                 /___ //////////////////////////_/ /
                 \____\________________________\_\/

                     Intel Corporation, RA1-303
                   Portland Technology Development
       =========================================================

              Phone: (503) 613-8055    FAX: (503) 613-8261
                   E-Mail: dbalvage at ptdcs2.intel.com



From edusilva at bahianet.com.br  Wed Jan 13 18:38:11 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Wed, 13 Jan 1999 15:38:11 -0200
Subject: Day job moog
Message-ID: <199901131821.QAA29362@postman.bahianet.com.br>

Malcolm McIntosh wrote:

> ...(The Moog consisted of a 3 boxes with modules in it and
> a separate keyboard.  The thing would fold up so that the outer two boxes
> closed over the center one.  If anyone knows what kind of Moog that was,
I
> appreciate the information!)...

And George replied:

> Hi malcolm
> I may very well be wrong but i think that monster Moog was used by Wendy
> (nee Walter) Carlos on " switched on Bach".
> I seem to remember it's shown on the album cover (a copy of which i 
sadly
> got rid of a long! time ago).
> I think it was the 101, or something like that?.
> 
> Live long and prosper.
> 
> George,8track man,Bath,U.K.

But I say:

No, it was the Moog IIIp. (p = portable) Similar to the Moog IIIc (c =
console).

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil



From varner at k-online.com  Wed Jan 13 18:55:31 1999
From: varner at k-online.com (Steve Varner)
Date: Wed, 13 Jan 1999 09:55:31 -0800
Subject: THE Ultimate Web Site
Message-ID: <369CDE0D.3B022CF9@k-online.com>

No... it doesn't exist yet. But, for those of you making web sites, this
is my wish list.

Some of you have already implemented some of these, but no site has all
of them. Please don't write indignantly saying, "Well I have this one!"
I know you do and I appreciate all your efforts.

1. A web-based forum so we don't have to get 150 messages in our mail
and only need to read the threads that interest us. Oh... and an archive
for this, too.

2. Schematics for each part of a synth (VCA, VCO, etc.) from many
sources - not just for one person's synth. Also, possible PCB layouts
for these.

3. Schematics, text and panels for commercial modulars of the past.

4. Lessons on building, including: panel construction, case
construction, PCB layout, soldering, troubleshooting, tuning, using an
O-scope, finding parts (Art's Theramin Page is really good for this last
one: http://home.att.net/~theremin1/ ).

5. Articles posted by DIY builders on various topics (including the
above topics). This could include more in-depth monthly features such as
how to make a certain thing from beginning to end.

6. Semiconductor data sheets and pinouts for ICs commonly used in DIY
applications - with links to the less common parts.

7. Lists of substitute ICs, especially for defunct parts (eg. What best
replaces the KE4859 FET in the ENS sawtooth-based VCO...).

8. Patches for modular synths to get certain effects (I haven't seen too
many of these around).

9. Info on synth-based musical groups (old and new).

10. A categorized links page: Semiconductor companies, personal pages,
people who sell modules and parts, other DIY pages, etc.

11. Articles for those of us who are not electronics experts on the
various parts of a music circuit: inverting amps, comparators, summing
nodes, Schmidt triggers, integrators, buffers, etc.

12. Reprints of articles from old magazines (with permission of course).

I'm sure I'll think of some more later, but even these twelve would make
one helluva great page!


Steve Varner
My work (not a synth page): http://www.bahai-site.org/
varner at k-online.com
webmaster at bahai-site.org






From costello at seanet.com  Wed Jan 13 19:00:49 1999
From: costello at seanet.com (Sean Costello)
Date: Wed, 13 Jan 1999 10:00:49 -0800
Subject: Heaviness (was Re: Day job)
References: <yam7682.2527.119057352@mail.mindspring.com>
Message-ID: <369CDF51.143B4165@seanet.com>

tomg wrote:

> I didn't mean to sound like I was bragging, I really do know
> better. It's just something someone said, I thought it was
> funny. Pretty dammed heavy thought. The first time my wife
> heard any of it she screwed up her face and said "It sounds
> like a wall of noise to me." A lot of people are really
> going to hate this crap...probibly my wife too. She likes the
> stuff that sounds like songs (humph)...but I like to hurt things
> and record it. A little brain damage now and then is a good
> thing...%:-)

Try hurting things and making it sound like songs. I have found that the
more melody, catchiness, hooks, and general "songability" you add in one
direction, the more noise, distortion, feedback, and evil sludge you can
add in the other direction.  There are plenty of bands out there that
are heavier than the ones I've listed, but at some point it becomes
unlistenable.  It is very easy to be unlistenable; the trick is taking
previously unlistenable sounds and putting them in a song where they
become listenable.  Riding that edge is where the excitement comes from.

A few other choices:

- "Come to Daddy" by Aphex Twin.  Take "Jimi" by the Butthole Surfers,
and put audio-rate jungle drums in there.  Brilliant.
- "Acid Police" (pronounced "A-CID! PO-LI-SAY!!") by the Boredoms.

As far as sonic heaviness, it is a difficult quality to quantify. For
some people, sludginess defines heaviness: lots of bass energy, sloppy
attacks on the notes, somewhat chaotic (think guitars and bass tuned
down several tones, run through a nasty fuzz like a Big Muff or
Superfuzz; the Fuzz Face also generates this sort of sludginess, with
its characteristic sluggish attack response).  Other people want a
sharpened crispness for their heaviness, which requires instruments at
tighter tension, and distortion that emphasizes the attacks and clarity
of the notes.  

A common theme for heaviness seems to be a "notched-out" midrange, with
lots of bass and sizzling treble.  All of the really "huge" sounding
distortion boxes do this, and most "heavy" bands try to approach this
with EQ.  I wonder if this sort of frequency response approximates the
ear's frequency response to sounds above a certain decibel level. For
myself, full-wave rectification (or maybe a balanced modulator where the
input signal is the same as the modulation signal) emulates the sort of
intermodulation effects that the ear produces at high volumes - in other
words, the sort of "internal" distortion I heard at Metallica in 1988 or
Soundgarden in 1991.  Add a few high sine wave generators for the
tinnitus, and you're set!  (Fortunately, I haven't been to any loud
concerts in a year, and my tinnitus is fading - gotta take care of those
ears.)

OK, enough ranting from me.  I just REALLY used to love very very loud
and distorted music. Still do, in smaller doses.

Sean Costello



From edusilva at bahianet.com.br  Wed Jan 13 19:15:49 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Wed, 13 Jan 1999 16:15:49 -0200
Subject: Mixer schematics and Rane's site
Message-ID: <199901131821.QAA00264@postman.bahianet.com.br>

But, if you really wanna try, there's lotsa good schemos and info at Rane's
site:

http://www.rane.com/

BTW, one of the most interesting site I've ever seen (kinda treasure island
for me)! Not synth-related but, what the hell, how would we hear our
bleeps, whooshes and blops without audio gear? I invite the whole list to
take a look - nobody will be disappointed, I assure.

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil

----------
> De: Tony Allgood <oakley at techrepairs.freeserve.co.uk>
> Para: synth diy <synth-diy at mailhost.bpa.nl>
> Assunto: Mixer schematics
> Data: Ter?a-feira, 12 de Janeiro de 1999 17:31
> 
> Hi Arpad and all,
> 
> My advice. Buy one. The price of Behringer, Spirit and Mackie is now so
> good it is very unlikely you will be able to build cheaper. I built my
> own out of front panels thrown in the skip outside the factory, but it
> is the components that are pricey. Mainly because of the large number of
> pots. You will be buying pots at about 1UKP a go. Soundcraft get them
> for a tenth of that, and the knobs are less still. The older Spirit
> range are still being sold. These are good value and use do not use SMD
> parts, and are therefore very easy to mod.
> 
> Regards,
> 
> Tony Allgood, Cumbria, UK




From DrXex at aol.com  Wed Jan 13 21:26:15 1999
From: DrXex at aol.com (DrXex at aol.com)
Date: Wed, 13 Jan 1999 15:26:15 EST
Subject: AW: MODULARS!!??
Message-ID: <fa5fd486.369d0167@aol.com>

In a message dated 1/13/99 8:10:49 AM Central Standard Time,
Juergen.Haible at nbgm.siemens.de writes:

<< This is not really Modular, but if you're tired of the usual
 "1 VCO-1VCF-1VCA" stuff - have you considered an EMS VCS-3 ?
 
 As for the new Modulars, stay away from low budget stuff.
 Invest in quality rather than quantity, and expand in the future.
 
 JH.
  >>

Yeah, the VCS3, thats awesome! if your a more live performance oriented person
get the Synthi AKS.  u can get em used or the "new" ones but i suggest used as
the used ones r around 2grand or more and the new ones r about 2700!!!!
but seriously this is a NICE piece of BEAUTIFUL gear i luv it... i wish i
could afford one...
~Dr Xex~



From guidogoe at xs4all.nl  Wed Jan 13 22:07:34 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Wed, 13 Jan 1999 21:07:34 GMT
Subject: WEB DIY database
Message-ID: <916258180-058496AEicMi@xs4all.nl>



>No... it doesn't exist yet. But, for those of you making web sites, this
>is my wish list.
>
>Some of you have already implemented some of these, but no site has all
>of them. Please don't write indignantly saying, "Well I have this one!"
>I know you do and I appreciate all your efforts. etc. etc.

I'm very short on this list, but I agree.

It is like this: years ago  I built a Vocoder (Dutch magazin (Elektuur design)).
And I sold it (so stupid) with the schematics inside the case.
Now I'm dying to rebuilt it... but I don't have the schematics anymore.

:-(

So to prevent that someone has to re-invent the wheel again and again, some diy-database would make so much difference!
As I have no homepage this very moment, I have  about 10MB space unused.
Still, Don't send me your DIY's tomorrow.
Let's discuss this seriously...

Regards, Guido Goebertus/THD studio
guidogoe at xs4all.nl




From magnus at analogue.org  Wed Jan 13 22:07:47 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 13 Jan 1999 22:07:47 +0100
Subject: WEB DIY database
In-Reply-To: Your message of "Wed, 13 Jan 1999 21:07:34 GMT"
References: <916258180-058496AEicMi@xs4all.nl>
Message-ID: <199901132107.WAA20290@mail2.it.kth.se>

>>>>> "GG" == Guido Goebertus <guidogoe at xs4all.nl> writes:

 >> No... it doesn't exist yet. But, for those of you making web sites, this
 >> is my wish list.
 >> 
 >> Some of you have already implemented some of these, but no site has all
 >> of them. Please don't write indignantly saying, "Well I have this one!"
 >> I know you do and I appreciate all your efforts. etc. etc.

 GG> I'm very short on this list, but I agree.

 GG> It is like this: years ago  I built a Vocoder (Dutch magazin (Elektuur design)).
 GG> And I sold it (so stupid) with the schematics inside the case.
 GG> Now I'm dying to rebuilt it... but I don't have the schematics anymore.

 GG> :-(

 GG> So to prevent that someone has to re-invent the wheel again and again, some diy-database would make so much difference!
 GG> As I have no homepage this very moment, I have  about 10MB space unused.
 GG> Still, Don't send me your DIY's tomorrow.
 GG> Let's discuss this seriously...

Check out Anders Sponton's webpage
http://www.tellus.vallentuna.se/gymninfo/personal/anders/andersus.html

He got the Elektor Vocoder in there.

Cheers,
Magnus



From stew at uq.net.au  Wed Jan 13 22:49:20 1999
From: stew at uq.net.au (Stewart Pye)
Date: Thu, 14 Jan 1999 08:49:20 +1100
Subject: Sequencer microprocessors
Message-ID: <199901132254.IAA31305@uq.net.au>

Hi There,

An 8051/8031 would do the job. You could use a keypad interrupt enabling
you to change from write to play mode while running. The built in uart will
handle midi. You shouldn't need too much discrete logic. A 4 input and on
the keypad matrix outputs could trigger an external interrupt. So you can
scan a heap of switches without using too much port space you can use a
74138 (3 to 8 line decoder) for the outputs to the keypad, permitting a 4
by 8 switch matrix using only 7 bits of the 8255 port C. An 8255 PIA would
be useful for the keypad and the led's.Hey, I might do this myself !!

Of course you could also use a Motorola or PIC microcontroller, I'd use an
8031 because thats what I know and I've found the instruction set to be
flexible and relatively easy to understand.  

Do you want to have midi control of the sound triggering or sound tone. The
triggering would be pretty easy, The tone/pitch would be harder. You'd need
a DtoA for a cv and then have the sound source parameters voltage
controllable.


Regards,

Stewart Pye


At 13:11 12/01/99 -0600, you wrote:
>"Budweiser [FTS]" wrote:
>> 
>> I am really interested in the idea of a cloning the 909 drum machine,
>> now that i have enough information about the circuits (especially the
>> the sample playback circuits for the hihats/cymbals).
>> 
>> What sort of processor would be best for such a design? Keeping in
>> mind I want to add more recent features found on modern instruments
>> like realtime midi control of the sounds, and leaving the sequencer
>> running while changing from play to write mode (like the 606).....
>> 
>WEll, a PIC would be good enough just to control the interface and
>memory. You would still prlly have to go down and dirty and use discrete
>logic otherwise you will be debugging forever with a play/write
>simultaneous mode.
>Rob
> 





From zimage at cs.wisc.edu  Wed Jan 13 22:53:48 1999
From: zimage at cs.wisc.edu (Tim Nowaczyk)
Date: Wed, 13 Jan 1999 15:53:48 -0600 (CST)
Subject: Heaviness (was Re: Day job)
In-Reply-To: <369CDF51.143B4165@seanet.com>
Message-ID: <Pine.GSO.3.96L.990113155004.11545A-100000@nova40.cs.wisc.edu>

The bands non (aka Boyd Rice), and coil rank up there for me.

see www.brainwashed.com for more info

Tim Nowaczyk




From ben at stuyts.nl  Wed Jan 13 23:31:26 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed, 13 Jan 99 23:31:26 +0100
Subject: Filters
In-Reply-To: <369C089C.BF64A477@earthlink.net>
References: <199901120017.QAA13988@smtp.ucsd.edu>
	<199901122228.XAA02731@daneel.stuyts.nl>
	<369C089C.BF64A477@earthlink.net>
Message-ID: <199901132231.XAA03378@daneel.stuyts.nl>

On Tue, 12 Jan 1999, Ian Fritz wrote:

> Hal Chamberlin's book shows how to do this. First, you make a diagram of
> the (analog) filter's topology, using integrators, amplifiers and
> summers.  Then for the digital implementation you just need to realize
> that a digital integrator is implemented by summing an input signal with
> a delayed version of itself: y(n) = x(n) + y(n-1). A state variable
> filter requires five additions and three multiplications per time step.
> Six lines of BASIC.

Right, that's exactly what I meant. Duh, I knew it couldn't be original.

Is that book still available?

Ben



From ben at stuyts.nl  Wed Jan 13 23:35:08 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Wed, 13 Jan 99 23:35:08 +0100
Subject: Filters
In-Reply-To: <369C3503.95F30E30@seanet.com>
References: <199901120017.QAA13988@smtp.ucsd.edu>
	<199901122228.XAA02731@daneel.stuyts.nl>
	<369C089C.BF64A477@earthlink.net> <369C3503.95F30E30@seanet.com>
Message-ID: <199901132235.XAA03383@daneel.stuyts.nl>

On Tue, 12 Jan 1999, Sean Costello wrote:

> There have been several attempts to bring the Moog filter into the
> digital realm, mostly based on the work of Timothy Stilson at CCRMA at
> Stanford (check out
> http://www-ccrma.stanford.edu/~stilti/papers/Welcome.html for his paper
> on the subject).

Great stuff! Thanks for the link.

Ben



From costello at seanet.com  Thu Jan 14 01:06:48 1999
From: costello at seanet.com (Sean Costello)
Date: Wed, 13 Jan 1999 16:06:48 -0800
Subject: Filters
References: <199901120017.QAA13988@smtp.ucsd.edu>
		<199901122228.XAA02731@daneel.stuyts.nl>
		<369C089C.BF64A477@earthlink.net> <199901132231.XAA03378@daneel.stuyts.nl>
Message-ID: <369D3518.199D838@seanet.com>

Ben Stuyts wrote:

> Is [Hal Chamberlin's Music for Microprocessors] still available?

I believe that you can order a photocopy version of it from Hal
Chamberlin directly, and that there is a link on the PAiA page. 
Otherwise, you can track it down at a used bookstore - I bought my copy
at Powell's Technical Books in Portland, Oregon, and they have copies in
occasionally.  Be sure to look for the 2nd edition (the 1st edition came
out in 1980, while the 2nd edition came out in 1985 and has far more
info).  

Sean Costello



From allan.houston at lineone.net  Thu Jan 14 01:08:33 1999
From: allan.houston at lineone.net (Allan)
Date: Thu, 14 Jan 1999 00:08:33 -0000
Subject: SSM2038 - Help
Message-ID: <000001be3f52$0647f5c0$a23e63c3@default>

I'm assuming that this is no longer made, but does anyone know of a
substitute, or where i could get/blag/steal one, bearing in mind i'm a
student and therefore skint

cheers




From JWBarlow at aol.com  Thu Jan 14 01:52:03 1999
From: JWBarlow at aol.com (JWBarlow at aol.com)
Date: Wed, 13 Jan 1999 19:52:03 EST
Subject: Heaviness (was Re: Day job)
Message-ID: <c8a54354.369d3fb3@aol.com>

1)Captain Beyond "Raging River of Fear"
2)Mahavishnu Orchestra (anything form the first three albums)
3)Glenn Branca (all)

Had to add these!



From bvdwal at casema.net  Thu Jan 14 08:30:26 1999
From: bvdwal at casema.net (Bauke van der Wal)
Date: Thu, 14 Jan 1999 08:30:26 +0100
Subject: Heaviness (was Re: Day job)
References: <Pine.GSO.3.96L.990113155004.11545A-100000@nova40.cs.wisc.edu>
Message-ID: <369D9D12.7ADF@casema.net>

Tim Nowaczyk wrote:
> 
> The bands non (aka Boyd Rice), and coil rank up there for me.
> see www.brainwashed.com for more info

heaviness in music ... it's a bit off topic, but i'm really into dark
ambient and death-industrial. for me it started with lustmord, brighter
death now, aube ... labels like ant-zen, malignant, cold meat industry
...

if anyone is interested in starting an off-list discussion on this
subject ? usage of synths and other instruments in this type of music ?
experiences ? effects ? filters ?! please mail privately ...

greetings,
b.
-- 
"we are ugly, but we have the music" - l. cohen



From hhelland at usa.net  Thu Jan 14 07:35:24 1999
From: hhelland at usa.net (Hallgeir Helland)
Date: 14 Jan 99 07:35:24 MET
Subject: ribbon controllers
Message-ID: <19990114063524.11348.qmail@www0k.netaddress.usa.net>

Hi there, it's me again :o)

I was wondering if there is some good info
on ribbon controllers around somewhere.
How they work, how to make, where to find,
and such DIY related info.

I'm going to have a joystick on my school-
synth-project (from one of those radio 
control thingys they fly their model 
airplanes with), and it'll be neat.

But it'd also be cool to have a ribbon ;->

Has anyone done this before?

Thanks,
Hallgeir

____________________________________________________________________
Get free e-mail and a permanent address at http://www.netaddress.com/?N=1



From budweiser at ozemail.com.au  Thu Jan 14 08:36:59 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Thu, 14 Jan 1999 18:06:59 +1030
Subject: Sequencer microprocessors
Message-ID: <005601be3f90$b2a8ccc0$9ad26ccb@ppp.ozemail.com.au>

>Do you want to have midi control of the sound triggering or sound tone. The
>triggering would be pretty easy, The tone/pitch would be harder. You'd need
>a DtoA for a cv and then have the sound source parameters voltage
>controllable.
>


Thanks for the advice...midi control is something i will be looking at,
triggering
first, and then control of all paramater (sound editing knobs etc).This is
where
things can get quite complex, and discrete logic would mean a huge PCB,
bigger
than the original 909!

I'm basically going to keep going until ive spent $1000 on parts, and see
just how
far i can go with the actual clone of the 909, and then the extra features..

<bUd>




From zzynt at swipnet.se  Thu Jan 14 09:26:45 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 14 Jan 1999 00:26:45 -0800
Subject: components!
Message-ID: <369DAA45.170D@swipnet.se>

Here is a link list for component sources
mailny in USA but may have links to other places too!

http://www.appliance.com/supplier.directory/cip669.htm

Im looking for plastic knoobs?
Any url's are welcome!!

BJ



From beszedes at cc.u-szeged.hu  Thu Jan 14 09:27:13 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Thu, 14 Jan 1999 09:27:13 +0100
Subject: WEB DIY database (Elektor Vocoder)
References: <916258180-058496AEicMi@xs4all.nl>
Message-ID: <369DAA61.8C6BBEB@cc.u-szeged.hu>



Guido Goebertus wrote:
> It is like this: years ago  I built a Vocoder (Dutch magazin (Elektuur design)).
> And I sold it (so stupid) with the schematics inside the case.
> Now I'm dying to rebuilt it... but I don't have the schematics anymore.
> 
> :-(

Hello!

I actually do have that article (in fact from the german version of
Elektor), but it's not online yet, so I will gladly send it to you when
I have it scanned.

Regards,
  Arpad.

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************



From beszedes at cc.u-szeged.hu  Thu Jan 14 09:32:07 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Thu, 14 Jan 1999 09:32:07 +0100
Subject: Heaviness (was Re: Day job)
References: <c8a54354.369d3fb3@aol.com>
Message-ID: <369DAB87.6F336A9F@cc.u-szeged.hu>

Say:

Skinny puppy (it's body-electro)

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************



From eduni at ucsd.edu  Thu Jan 14 10:54:38 1999
From: eduni at ucsd.edu (Ethan Duni)
Date: Thu, 14 Jan 1999 01:54:38 -0800 (PST)
Subject: Heaviness (was Re: Day job)
Message-ID: <199901140954.BAA10427@smtp.ucsd.edu>

At 09:32 AM 1/14/99 +0100, you wrote:
>Say:
>
>Skinny puppy (it's body-electro)

-specifically the song "Melt"

Ethan




From vco at mindspring.com  Thu Jan 14 11:05:16 1999
From: vco at mindspring.com (tomg)
Date: Thu, 14 Jan 1999 05:05:16 -0500
Subject: Heaviness (was Re: Day job)
In-Reply-To: <369DAB87.6F336A9F@cc.u-szeged.hu>
Message-ID: <yam7683.810.119689800@mail.mindspring.com>

Anybody into Numb or Swamp Terriorist. It's sample stuff
but I think it's pretty heavy. I think NIN might have spent 
a some time with the first Numb album. I heard it was banned
in some places. Who are those guys anyway?

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From Colin.Fraser at scottishpower.plc.uk  Thu Jan 14 11:30:56 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Thu, 14 Jan 1999 10:30:56 -0000
Subject: Sequencer microprocessors
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2B5@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Budweiser [FTS] [mailto:budweiser at ozemail.com.au]
> Sent: 14 January 1999 07:37
> To: synth-diy at mailhost.bpa.nl; Stewart Pye
> Subject: Re: Sequencer microprocessors
> 
> Thanks for the advice...midi control is something i will be 
> looking at,
> triggering
> first, and then control of all paramater (sound editing knobs 
> etc).This is
> where
> things can get quite complex, and discrete logic would mean a 
> huge PCB,
> bigger
> than the original 909!
> 
> I'm basically going to keep going until ive spent $1000 on 
> parts, and see
> just how
> far i can go with the actual clone of the 909, and then the 
> extra features..

The 808/909 clone I built cost me about 400ukp in parts (and probably 30% of
my spare time over a 2 year period).
That included a 4 unit rack case that cost 40ukp, and PSU components that
cost another 20ukp.

My unit only responds to midi triggers, and acts as a midi to cv convertor
too. The processor handling this is a 6502, and I have written a drum
pattern sequencer that runs on another 6502 machine that could easily be
ported to run on the internal processor of my drum unit - I would just need
to add a keyboard and display unit.
That would probably only add another 100ukp in parts at the most.
I chose to keep the sequencing separate for flexibility.

At the moment I use a TR626 for drum patterns. This feeds a BBC Micro (6502
based home computer) via midi, which passes the 626 data thru to the drum
module adding data from a pattern based 8 track sequencer on the BBC. It
also outputs din sync for my 303/606/202.
The next stage is to build a hardware pattern editing interface for the BBC
sequencer - probably 16 or 32 knobs and switches.
I'll also be adding cv/gate inputs to the BBC sequencer so it can record
patterns from my Pro-One or 303 internal sequencers.

You'd be insane to build a sequencer in discrete logic (unless you want an
analogue sequencer). 
With any 8-bit micro (80x1, z80, 6502...) you will be able to build a
sequencer will all the features of the 909 sequencer, but with the ability
to change between write and play on the fly.
The way I wrote my sequencer, there is no separate write / play mode. There
are separate keys for editing patterns and selecting patterns etc. so you
can always edit any pattern that is playing.

Midi control over the sound parameters in the 909 circuits will be quite a
job. Most of the pots will need to be replaced with OTAs, and you'll need to
provide all the pots for manual control with a scanning circuit to read
their values.
If I was going to do that, I would probably just build the knobs as a
general purpose controller unit so I could use it to edit other devices than
the drums.


Colin f



From allan.houston at lineone.net  Thu Jan 14 13:17:35 1999
From: allan.houston at lineone.net (Allan)
Date: Thu, 14 Jan 1999 12:17:35 -0000
Subject: Heaviness 
In-Reply-To: <369CDF51.143B4165@seanet.com>
Message-ID: <000001be3fb7$de94a080$a8f0abc3@default>

Don't know if anyone will now what i'm talking about, but in terms of
eardrum abuse, i don't think you can get much darker/heavier,than speedcore
or noisecore.  Stuff goes at about 300bpm+ (sometimes even quicker),
personally i can't stand it and think you can goe heavier just by going
slower and useing darker sample(don't ask me to explain what i mean, cause i
can't define a dark sample, i just know what it sounds like)

Allan

		"If i had to explain
        you wouldn't understand."




From MHELIN at tne01.ntc.nokia.com  Thu Jan 14 13:26:24 1999
From: MHELIN at tne01.ntc.nokia.com (Mikko Helin)
Date: Thu, 14 Jan 1999 14:26:24 +0200
Subject: THE Ultimate Web Site
Message-ID: <990114142624.5300f2e1@tnclus.ntc.nokia.com>

From:	SMTP%"varner at k-online.com" 13-JAN-1999 20:05:21.35
To:	MHELIN
CC:	
Subj:	THE Ultimate Web Site

Message-ID: <369CDE0D.3B022CF9 at k-online.com>
Date: Wed, 13 Jan 1999 09:55:31 -0800
From: Steve Varner <varner at k-online.com>
Reply-To: varner at k-online.com
X-Mailer: Mozilla 4.04 (Macintosh; I; PPC)
MIME-Version: 1.0
To: synth-diy <synth-diy at mailhost.bpa.nl>
Subject: THE Ultimate Web Site
Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353"
Content-Transfer-Encoding: 7bit
Sender: owner-synth-diy at mailhost.bpa.nl
Precedence: bulk
Good ideas, I think a synth-diy version of Ampage
(http://www.firebottle.com/ampage/) is what is really needed.
Kevin Lightner's Synthfool pages (www.synthfool.com) come close 
(there seems be also a bbs section now, aka the Synthfool Message Board).
There are also combined WWW & email pages like f.ex.
www.egroups.com/lists/cubase, and many free message board sites also.

-Mikko

========================================================================


No... it doesn't exist yet. But, for those of you making web sites, this
is my wish list.

Some of you have already implemented some of these, but no site has all
of them. Please don't write indignantly saying, "Well I have this one!"
I know you do and I appreciate all your efforts.

1. A web-based forum so we don't have to get 150 messages in our mail
and only need to read the threads that interest us. Oh... and an archive
for this, too.

2. Schematics for each part of a synth (VCA, VCO, etc.) from many
sources - not just for one person's synth. Also, possible PCB layouts
for these.

3. Schematics, text and panels for commercial modulars of the past.

4. Lessons on building, including: panel construction, case
construction, PCB layout, soldering, troubleshooting, tuning, using an
O-scope, finding parts (Art's Theramin Page is really good for this last
one: http://home.att.net/~theremin1/ ).

5. Articles posted by DIY builders on various topics (including the
above topics). This could include more in-depth monthly features such as
how to make a certain thing from beginning to end.

6. Semiconductor data sheets and pinouts for ICs commonly used in DIY
applications - with links to the less common parts.

7. Lists of substitute ICs, especially for defunct parts (eg. What best
replaces the KE4859 FET in the ENS sawtooth-based VCO...).

8. Patches for modular synths to get certain effects (I haven't seen too
many of these around).

9. Info on synth-based musical groups (old and new).

10. A categorized links page: Semiconductor companies, personal pages,
people who sell modules and parts, other DIY pages, etc.

11. Articles for those of us who are not electronics experts on the
various parts of a music circuit: inverting amps, comparators, summing
nodes, Schmidt triggers, integrators, buffers, etc.

12. Reprints of articles from old magazines (with permission of course).

I'm sure I'll think of some more later, but even these twelve would make
one helluva great page!


Steve Varner
My work (not a synth page): http://www.bahai-site.org/
varner at k-online.com
webmaster at bahai-site.org






From martin.czech at intermetall.de  Thu Jan 14 14:03:29 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 14 Jan 1999 14:03:29 +0100 (MET)
Subject: archive update
Message-ID: <199901141303.OAA20523@window.intermetall.de>

I just want to say that the DIY Grey Pages archive was just updated.
Now the list mail traffic from 1995-1998 is available.

The Herbert Eimert samples are gone, due to space limit.

However , due to a late request I'm able to make some more copies
of the whole CD.

The url is at my homepage: http://www.geocities.com/SoHo/Museum/4459/
and then under DIY - DIY Grey Pages.

Thank you.

m.c.

------------------------------------------------------------------------
m.c. (alias mad scientist) has made it finally: 3 CDs ? 72 minimum ready.
Visit my homepage at http://www.geocities.com/SoHo/Museum/4459/index.html





From martink at cix.co.uk  Thu Jan 14 15:45:00 1999
From: martink at cix.co.uk (Martin J Keefe)
Date: Thu, 14 Jan 1999 14:45 +0000 (GMT)
Subject: Filters
In-Reply-To: <369D3518.199D838@seanet.com>
Message-ID: <memo.19990114144537.251A@martink.compulink.co.uk>

> occasionally.  Be sure to look for the 2nd edition (the 1st edition came
> out in 1980, while the 2nd edition came out in 1985 and has far more
> info).  

I managed to find a paperback copy in the library. It appears to be 1st 
edition (copyright 1980) but was printed in 1991. Anybody know why this 
should be? Seems stupid to keep reprinting an old edition.

  ]\/[artin Keefe ][ Dorking,Surrey,UK ][ martink at cix.co.uk



From cyborg0 at GlobalEyes.net  Thu Jan 14 17:40:19 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Thu, 14 Jan 1999 10:40:19 -0600
Subject: Sequencer microprocessors
References: <005601be3f90$b2a8ccc0$9ad26ccb@ppp.ozemail.com.au>
Message-ID: <369E1DF3.6A8C430E@globaleyes.net>

"Budweiser [FTS]" wrote:
> 
> >Do you want to have midi control of the sound triggering or sound tone. The
> >triggering would be pretty easy, The tone/pitch would be harder. You'd need
> >a DtoA for a cv and then have the sound source parameters voltage
> >controllable.
> >
> 
> Thanks for the advice...midi control is something i will be looking at,
> triggering
> first, and then control of all paramater (sound editing knobs etc).This is
> where
> things can get quite complex, and discrete logic would mean a huge PCB,
> bigger
> than the original 909!
> 
Oh NO! :) I meant SOME discrete logic, not a ton of it.. When I had to
do designs for the 6502 and 6800 for school, I used discrete logic as a
crutch so I didnt have to sit there all stinking day keying in ASM on a
numerical keypad! God that SUX! 
It was just easier to do some things with discrete logic rather than
debug a routine forever... looking only at numbers for 4-5 hrs makes you
lose your sanity..Now was I using index or relative addressing? uh oh...

Rob



From s9610068 at chelt.ac.uk  Thu Jan 14 18:34:19 1999
From: s9610068 at chelt.ac.uk (James Dunn)
Date: Thu, 14 Jan 1999 17:34:19 +0000
Subject: CS-50 Schematics.
Message-ID: <369E2A9B.384C@chelt.ac.uk>

Hi all,

Does anyone have the manual and schematics for the Yamaha CS-50? I have
recently purchased one and would like to modify it. I approached Yamaha
here in the U.K. and they want about ?23 (U.K. sterling). If anyone has
the manual with schematics I would be more than willing to pay postage
and photocopying costs.

Thanks,

James.




From tom.verheyden at village.uunet.be  Thu Jan 14 20:18:39 1999
From: tom.verheyden at village.uunet.be (be053520)
Date: Thu, 14 Jan 1999 20:18:39 +0100
Subject: NEW DAY JOB!!!!
Message-ID: <000001be412f$f3ecbfc0$559007c2@be053520>

My old day job: Troubleshooter at Alcatel Bell

NOW: Starting monday as service engineer at Roland Benelux (BELGIUM)
I'll be repairing Roland synths from TB/TR to JP8080,

so if you've any problems with those machines, mail me!

(sorry couldn't resist to mail this....I'm just to happy!! :-))

Tom Verheyden


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From vco at mindspring.com  Thu Jan 14 21:10:27 1999
From: vco at mindspring.com (tomg)
Date: Thu, 14 Jan 1999 15:10:27 -0500
Subject: Heaviness
In-Reply-To: <000001be3fb7$de94a080$a8f0abc3@default>
Message-ID: <yam7683.1355.118825224@mail.mindspring.com>

I forgot 16Volt! I've got "Wisdom" on the cd right now.

That's it I'm done. Back OT.

-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From Romeo_Fahl at stream.com  Thu Jan 14 21:12:00 1999
From: Romeo_Fahl at stream.com (Romeo_Fahl at stream.com)
Date: Thu, 14 Jan 1999 12:12:00 -0800
Subject: 2SA798 - Cheap Dual Matched PNP Pair?
Message-ID: <852566F9.006ED8EA.00@galaxy.support.stream.com>



I recently placed an order with MCM for a few parts.  I ordered a few 2SA798s
because the MS20 KLM 127 VCF
(http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/schematics/KLM-307.GIF)
uses them in the expo converter.  I have no data sheet that covers this part,
but I am wondering how closely the two PNPs in the package are matched (ie good
enough for a VCO?).  Also, does anyone have a pinout?  For $.24 these are a
steal!!!

Romeo





From thudson at cygnus.com  Thu Jan 14 21:38:18 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Thu, 14 Jan 1999 15:38:18 -0500
Subject: Ignore test
Message-ID: <369E55BA.B54577BF@cygnus.com>


Is the list down?



From guidogoe at xs4all.nl  Thu Jan 14 21:39:02 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Thu, 14 Jan 1999 20:39:02 GMT
Subject: Elektor Vocoder/DSP talk
References: <369DAA61.8C6BBEB@cc.u-szeged.hu>
Message-ID: <916347874-712818AEicMi@xs4all.nl>

Hello Arpad, you wrote:

>I actually do have that article (in fact from the german version of
>Elektor), but it's not online yet, so I will gladly send it to you when
>I have it scanned.

The schematics are also on a swedish site.
Magnus suplied me the URL of Anders Sponton's DIY site.
But it wasn't of any use at this moment.
The files there are pretty large in size and as I'm working at the moment on a humble 4MB Atari030 machine, I couldn't download them at all.
I really should upgrade memory, and I think I will pretty soon.

But, IF it isn't to much trouble for you, and IF you have the time: Please do! (GIF is a format my machine handles well...)

Thinking over the DSP talk on this group, I thought:
Wouldn't it be nice to have a schematics drawing program able to connect resistors/ caps/ opamps/ mos logic or whatever virtually and then you push a button and  DSP code comes out?.
What a wonderful world...

Regards,

Guido Goebertus/THD Studio




From martin at manikin.force9.co.uk  Thu Jan 14 22:51:58 1999
From: martin at manikin.force9.co.uk (Martin Fay)
Date: Thu, 14 Jan 1999 21:51:58 GMT
Subject: Heaviness (was Re: Day job)
In-Reply-To: <yam7683.810.119689800@mail.mindspring.com>
References: <yam7683.810.119689800@mail.mindspring.com>
Message-ID: <36a1df91.3954630@relay.force9.net>

Tom wrote:
>Anybody into Numb or Swamp Terriorist. It's sample stuff
>but I think it's pretty heavy. I think NIN might have spent 
>a some time with the first Numb album. I heard it was banned
>in some places. Who are those guys anyway?

The mainstay of Numb is Don Gordon, and the band originates from
Vancouver...I believe Don was in a band with Cevin Key before he
formed Skinny Puppy. Another Vancouver project to keep an eye out for
is Decree/Wake of Devastation.


Martin



From varner at k-online.com  Thu Jan 14 23:05:02 1999
From: varner at k-online.com (Steve Varner)
Date: Thu, 14 Jan 1999 14:05:02 -0800
Subject: ribbon controllers
References: <19990114063524.11348.qmail@www0k.netaddress.usa.net>
Message-ID: <369E6A0C.EA4AFC49@k-online.com>

There is information on building a ribbon controller in "Electronic Music
Circuits" by B. Klein. This one is basically a rheostat using a long strip
of conductive foam such as you find protecting semiconductors from static
charges. The foam is placed on non-conductive material (wood, etc.) and two
metal plates are attached at each end. One plate is connected to ground and
the other to a +15V supply. Now, at a slight distance above the foam you
place a piece of metallized mylar film that leads to the Control Voltage out
jack. When you press on the mylar film it makes contact with the foam
somewhere between 0 and 15V. As you slide your finger along the film, the
voltage changes. I haven't made one of these, but I plan to.

SV

Hallgeir Helland wrote:

> Hi there, it's me again :o)
>
> I was wondering if there is some good info
> on ribbon controllers around somewhere.
> How they work, how to make, where to find,
> and such DIY related info.
>
> I'm going to have a joystick on my school-
> synth-project (from one of those radio
> control thingys they fly their model
> airplanes with), and it'll be neat.
>
> But it'd also be cool to have a ribbon ;->
>
> Has anyone done this before?
>
> Thanks,
> Hallgeir
>
> ____________________________________________________________________
> Get free e-mail and a permanent address at http://www.netaddress.com/?N=1






From edusilva at bahianet.com.br  Fri Jan 15 00:04:15 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Thu, 14 Jan 1999 21:04:15 -0200
Subject: MCS 70 (Memory Controlled Synthesizer)
Message-ID: <199901142306.VAA04250@postman.bahianet.com.br>

Does anybody in the list know this machine?

It was used to make all the sounds in the album "Automat" (EMI - Italy).
It's an electronic classic here in Brazil, as one of the tunes (Droid), was
used as the main theme by a TV news program (Jornal da Globo) in 1980 - it
reached the Top Ten that year. Not a bad feat, for a eletronic instrumental
piece!

Here's the sleeve notes (LP - 1978. never found it on CD)

"Music and sounds conceived, arranged and played by Romano Mussumara and
Claudio Gizzi. All tunes realized entirely with sounds programmed by Mario
Maggi using the MCS70 (Memory Controlled Synthesizer). Sound engineer:
Luciano Torani."

Sounds to me as an one-of-a-kind analog beast, built by some mad types at
an University, full of jacks and knobs, with hundreds of blinking LED's ...
or am I dreaming?

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil




From ben at stuyts.nl  Fri Jan 15 00:19:51 1999
From: ben at stuyts.nl (Ben Stuyts)
Date: Fri, 15 Jan 99 00:19:51 +0100
Subject: Filters
In-Reply-To: <369D3518.199D838@seanet.com>
References: <199901120017.QAA13988@smtp.ucsd.edu>
	<199901122228.XAA02731@daneel.stuyts.nl>
	<369C089C.BF64A477@earthlink.net>
	<199901132231.XAA03378@daneel.stuyts.nl> <369D3518.199D838@seanet.com>
Message-ID: <199901142319.AAA04141@daneel.stuyts.nl>

On Wed, 13 Jan 1999, Sean Costello wrote:

> Ben Stuyts wrote:
>
> > Is [Hal Chamberlin's Music for Microprocessors] still available?
>
> I believe that you can order a photocopy version of it from Hal
> Chamberlin directly, and that there is a link on the PAiA page.

Thanks! I've sent him an email. I now remember that I actually read the book  
when I was at university. That was early eighties, so it must have been the  
1st edition. I remember it as a very interesting, hands-on book.

Ben



From adaaxs at erols.com  Fri Jan 15 01:25:01 1999
From: adaaxs at erols.com (J.G. Wong)
Date: Fri, 15 Jan 1999 01:25:01 +0100
Subject: components!
References: <369DAA45.170D@swipnet.se>
Message-ID: <369E8AAB.FDB32787@erols.com>

Hi Guys,

    I just got some Focusrite pieces (Green series) and think their
knobs may be good for use on some of our DIY stuff especially like
filter modules.

    Anybody see anything comparable in the US ?

G Wong



BJ wrote:

> Here is a link list for component sources
> mailny in USA but may have links to other places too!
>
> http://www.appliance.com/supplier.directory/cip669.htm
>
> Im looking for plastic knoobs?
> Any url's are welcome!!
>
> BJ




From uzs159 at uni-bonn.de  Fri Jan 15 01:40:42 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Fri, 15 Jan 1999 01:40:42 +0100
Subject: 2SA798 - Cheap Dual Matched PNP Pair?
In-Reply-To: <852566F9.006ED8EA.00@galaxy.support.stream.com>
Message-ID: <3.0.5.32.19990115014042.008b3800@ibm.rhrz.uni-bonn.de>

At 12:12 14.01.99 -0800, you wrote:
>
>
>I recently placed an order with MCM for a few parts.  I ordered a few 2SA798s
>because the MS20 KLM 127 VCF
>(http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/schem
atics
> /KLM-307.GIF)
>uses them in the expo converter.  I have no data sheet that covers this part,
>but I am wondering how closely the two PNPs in the package are matched (ie
good
>enough for a VCO?).  Also, does anyone have a pinout?  For $.24 these are a
>steal!!!
>
>Romeo
>
>
I wonder if there are datasheets (online) available for all this 2SA.. 2SC
japanese transistors, I bet there are quite a few interesting components
among these (see 2SC1583).
I've tried to search questlink but with little success.
Anyone knows who manufactures these?

Rene


             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From DubbleDub at aol.com  Fri Jan 15 01:47:00 1999
From: DubbleDub at aol.com (DubbleDub at aol.com)
Date: Thu, 14 Jan 1999 19:47:00 EST
Subject: Touchpad controllers was Re: ribbon controllers
Message-ID: <fe778d97.369e9004@aol.com>

Is there a way to use a generic windows touchpad to send MIDI controller/sysex
data ... ala the Korg Z1 ... more dynamic than a ribbon.

An option could be to wire up the touchpad into PC1600, to use its software.
Any PC1600 users here?

Any interest in this type of interface?



From uzs159 at uni-bonn.de  Fri Jan 15 02:23:36 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Fri, 15 Jan 1999 02:23:36 +0100
Subject: Japanese Dual Transistors
Message-ID: <3.0.5.32.19990115022336.008ea970@ibm.rhrz.uni-bonn.de>

While searching for info on the 2SC1583 and the 2SA798 I found this
interesting pair of pairs :) at Toshiba.

2SA1349 Dual PNP (specs say 0mV min and 10mV max. delta Vbe, but no typ.)
2SC3381 Dual NPN (complementary to 2SA1349 same specs)

The 10mV max spec'd delta Vbe is not exactly what I would expect in a 
matched pair, but the data sheet claims "good pair characteristics"
The 0mV min is kind of funny :)

2SK389 Dual N-channel jFET (max 20mV delta Vgs)
2SJ109 Dual P-channel jFET (complementary to 2SK389)

For all the germans: Reichelt has all of them.

Rene





             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From thudson at cygnus.com  Fri Jan 15 03:29:32 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Thu, 14 Jan 1999 21:29:32 -0500
Subject: Touchpad controllers was Re: ribbon controllers
References: <fe778d97.369e9004@aol.com>
Message-ID: <369EA80C.DBB1B1BA@cygnus.com>

DubbleDub at aol.com wrote:
> 
> Is there a way to use a generic windows touchpad to send MIDI controller/sysex
> data ... ala the Korg Z1 ... more dynamic than a ribbon.
> 
> An option could be to wire up the touchpad into PC1600, to use its software.
> Any PC1600 users here?
> 
> Any interest in this type of interface?

I tried out a synthesis program called SuperCollider
(http://www.audiosynth.com/index.html) on a borrowed Mac.
It allowed you to assign the X and Y components of the mouse
to any two parameters. This is serious fun. 

Thomas



From batzman at all-electric.com  Fri Jan 15 04:09:17 1999
From: batzman at all-electric.com (The Dark force of dance)
Date: Fri, 15 Jan 1999 13:09:17 +1000
Subject: [Digital_Hell] Touchpad controllers was Re: ribbon
  controllers
Message-ID: <3.0.32.19990115130727.0073f9b4@mail.chariot.net.au>

Y-ellow Dubble 'n' y'all.

At 07:47 PM 01/14/99 EST, DubbleDub at aol.com wrote:
>Is there a way to use a generic windows touchpad to send MIDI
controller/sysex
>data ... ala the Korg Z1 ... more dynamic than a ribbon.
>
>An option could be to wire up the touchpad into PC1600, to use its software.
>Any PC1600 users here?
>
>Any interest in this type of interface?

I had thought of doing this. I have a little glide point gizmo here I use.
It's got advantages over a trackball but because it doesn't move under your
fingers, you tend to trace a kind of jerky movement some times. I like it
though.

There was, I saw somewhere, a little program someone wrote that translated
the mouse into MIDI. The shot would be then to get one of Philip Pilgrim's
([ [ [ [ [[The Lab] ] ] ] ] http://robotnik.com/the_lab/) UP kits. This can
turn an old PC into a 1600-like controller. Bung a midi card in it or an
old sound card and you've got yourself a controller with touch pad. I'm
sure if you put it to Philip, he could integrate the idea directly into his
UP.

What I had planned, but will be lucky to get round to doing, was a sort of
stand alone version of his UP. using a small atmel micro. This could send
and receive MIDI and read up to 256 pots. I have a pile of Joysticks now
which I had planed to use instead of sliders. Much nicer when you're doing
things like NRPNs.

I also have some documentation which shows how to read a mouse here
somewhere. It's easy but you'll need another micro on the end of it. With
my glide-point thingy at least, you couldn't just take some output from it
directly analogue.They don't work like that. They sense capacitance of your
finger on a plate. There are many ways to do it and I'm not sure exactly
how they do it in this case but it could be rather like a theramin in that
the frequency of a pair of oscillators could change depending on the x/y
coordinates. the on-board micro translates this into mouse movement.
Someone else here might have a better handle on how they actually do the
sensing but I know it's capacitively driven. You can't actually drive the
device with stick or something. You have to use your finger. Kind of like
an extension of the capacitive touch-switch.

I would seriously suggest that it would be worth talking to Philip about
his UP. It's very simple and you can use any ol' PC as the brains. I've got
a couple of ol' 286 Lap-tops here that I was thinking of using. Oh
actually, I think if I remember correctly, Philip's UP has a kind of fudged
MIDI port of it's own into the bargain. I know it's really simple and easy
to build.

Check it out.

Hope this helps.

Be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|       



From theremin1 at worldnet.att.net  Fri Jan 15 06:40:47 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Thu, 14 Jan 1999 21:40:47 -0800
Subject: ribbon controllers
Message-ID: <004501be4049$9b4a9860$f8794e0c@hpcustomer>

Some interesting information is at:
http://www.prismnet.com/~tpolk/music/music.html.
Also see:  http://www.geocities.com/Vienna/4611/tannerin.html and
http://www.geocities.com/Vienna/4611/PTE-TPage.html.

-Art

-----Original Message-----
From: Steve Varner <varner at k-online.com>
To: synth-diy <synth-diy at mailhost.bpa.nl>
Date: Thursday, January 14, 1999 3:58 PM
Subject: Re: ribbon controllers


>There is information on building a ribbon controller in "Electronic Music
>Circuits" by B. Klein. This one is basically a rheostat using a long strip
>of conductive foam such as you find protecting semiconductors from static
>charges. The foam is placed on non-conductive material (wood, etc.) and two
>metal plates are attached at each end. One plate is connected to ground and
>the other to a +15V supply. Now, at a slight distance above the foam you
>place a piece of metallized mylar film that leads to the Control Voltage
out
>jack. When you press on the mylar film it makes contact with the foam
>somewhere between 0 and 15V. As you slide your finger along the film, the
>voltage changes. I haven't made one of these, but I plan to.
>
>SV
>
>Hallgeir Helland wrote:
>
>> Hi there, it's me again :o)
>>
>> I was wondering if there is some good info
>> on ribbon controllers around somewhere.
>> How they work, how to make, where to find,
>> and such DIY related info.
>>
>> I'm going to have a joystick on my school-
>> synth-project (from one of those radio
>> control thingys they fly their model
>> airplanes with), and it'll be neat.
>>
>> But it'd also be cool to have a ribbon ;->
>>
>> Has anyone done this before?
>>
>> Thanks,
>> Hallgeir
>>
>> ____________________________________________________________________
>> Get free e-mail and a permanent address at http://www.netaddress.com/?N=1
>
>
>




From martin.czech at intermetall.de  Fri Jan 15 07:39:14 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 15 Jan 1999 07:39:14 +0100 (MET)
Subject: Japanese Dual Transistors
Message-ID: <199901150639.HAA27170@window.intermetall.de>

> While searching for info on the 2SC1583 and the 2SA798 I found this
> interesting pair of pairs :) at Toshiba.
> 
> 2SA1349 Dual PNP (specs say 0mV min and 10mV max. delta Vbe, but no typ.)
> 2SC3381 Dual NPN (complementary to 2SA1349 same specs)
> 
> The 10mV max spec'd delta Vbe is not exactly what I would expect in a 
> matched pair, but the data sheet claims "good pair characteristics"
> The 0mV min is kind of funny :)
> 
> 2SK389 Dual N-channel jFET (max 20mV delta Vgs)
> 2SJ109 Dual P-channel jFET (complementary to 2SK389)
> 
> For all the germans: Reichelt has all of them.
> 

We had this before:

Is dual == matched ? I gues not, other wise they would say so.
If this is the case then you get closer temperature contact as
a selected discrete pair, but the parameters may vary as wide
as in the discrete case (you are interested in collector current
matching as well). Seems you still have to select good ones.
So , they seem to be cheaper, but have also not so good matching.

m.c.

m.c. 




From ming at gol.com  Fri Jan 15 12:44:18 1999
From: ming at gol.com (Minoru Yokoo)
Date: Fri, 15 Jan 1999 20:44:18 +0900 (JST)
Subject: 2SA798 - Cheap Dual Matched PNP Pair?
In-Reply-To: <3.0.5.32.19990115014042.008b3800@ibm.rhrz.uni-bonn.de>
References: <852566F9.006ED8EA.00@galaxy.support.stream.com>
Message-ID: <199901151144.UAA08790@smtp02.mail.gol.com>

At 1:40 AM +0100 99.1.15, Rene Schmitz wrote:
> At 12:12 14.01.99 -0800, you wrote:

> I wonder if there are datasheets (online) available for all this 2SA.. 2SC
> japanese transistors, I bet there are quite a few interesting components
> among these (see 2SC1583).

As far as I know, there aren't any "all-in-one" or useful online datasheets
for Japanese transistors (I'm Japanese, so I've searched both in Japan and
outside). You can find some at individual manufacturer's sites, but they
usually only carry info for current models.

FYI, I've looked at a few ads and the 2SA798 is/was made by Mitsubishi and
the going price in Tokyo is about 80 Yen per unit (about USD$0.75) or 6,000
Yen (about USD$55) for a hundred. If you want to buy them in this price
range, you can buy them here (and I don't work for them or anything, just
looked up an ad):

Fujisho Denshi Co. Ltd
Art Building 12-8 Shibuya 2 chome, Shibuya-ku, Tokyo 150-0002 Japan
Ph 813-3499-0981
Fx 813-3499-0251

Minoru







From THEKn0TiS at aol.com  Fri Jan 15 18:27:52 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Fri, 15 Jan 1999 12:27:52 EST
Subject: need 80017A vcf/vca and MC5534A waveshaper or equivilent for a hs60
Message-ID: <182b694.369f7a98@aol.com>

my roland hs60 has one dead voice so im on the prowl for these components to
fix her if any one knows a source or has these i would like to buy them
thanx
shawn



From pinknoiz at pinknoiz.com  Fri Jan 15 19:14:49 1999
From: pinknoiz at pinknoiz.com (Bob Gonsalves)
Date: Fri, 15 Jan 1999 10:14:49 -0800
Subject: Touchpad controllers was Re: ribbon controllers
In-Reply-To: <369EA80C.DBB1B1BA@cygnus.com>
References: <fe778d97.369e9004@aol.com>
Message-ID: <v04020a02b2c535b6e888@[207.21.142.173]>

>
>I tried out a synthesis program called SuperCollider
>(http://www.audiosynth.com/index.html) on a borrowed Mac.
>It allowed you to assign the X and Y components of the mouse
>to any two parameters. This is serious fun.


Also Max, on the Macintosh, allows one to do this trivially.
A commercial product, it offers a different type of DIY, where you build
your own MIDI instruments by wiring building blocks together.




From karlto at invalid.ed.ntnu.no  Fri Jan 15 20:07:34 1999
From: karlto at invalid.ed.ntnu.no (Karl Helmer Torvmark)
Date: Fri, 15 Jan 1999 20:07:34 +0100 (CET)
Subject: day job
In-Reply-To: <199901110721.XAA01828@shell9.ba.best.com>
Message-ID: <Pine.LNX.4.05.9901151956430.12302-100000@invalid.ed.ntnu.no>


I'm in my last year studying for a degree in EE and acoustics. I'm
involved in running an electronics workshop driven by students, so I have
access to a few luxury items (big UV-lighting table, etching machine,
automatic drill). 

With the current discussions on soldering SMD components, I'd like to
point out that as long as you have a good tip on your soldering station,
a set of good pliers, a magnifying glass and a steady hand, you can
probably work with everything except ball-grid arrays. But then, these are
only used in the REALLY big processors, DSPs and FPGAs, so...

Also, by using a good quality transparency (not ordinary
laser-transperancies, but slighly opaque/matte ones), a good laser printer
and good quality photo-PCBs, good two-sided PCBs with down to 8mil/8mil
spacing can be made with a resonable yield.

You can really do very much with rather modest equipment... 

--------
Karl H.




From jaheikka at cc.spt.fi  Fri Jan 15 20:16:38 1999
From: jaheikka at cc.spt.fi (Janne Heikkarainen)
Date: Fri, 15 Jan 1999 21:16:38 +0200 (EET)
Subject: 2N4391/92
Message-ID: <Pine.SOL.3.91.990115211423.25154A-100000@jazz>

it seems that i can't locate this transistor anywhere...are there any good 
replacements for it?

.biotek




From Barry.L.Klein at wdc.com  Fri Jan 15 23:29:41 1999
From: Barry.L.Klein at wdc.com (Barry L Klein)
Date: Fri, 15 Jan 1999 14:29:41 -0800 (Pacific Standard Time)
Subject: day job
Message-ID: <ISSMTP.1.3(1).19990115142941.4294010239D@Corp.wdc.com>


Hi all,
I've been here at WDC almost 9 years working on disk drive reliability and
design improvement etc.  All SMT with really damn small stuff.  Luckily I
haven't had to work much with the 2-3" drives we had a while back.  It is
all workable you just have to be able to see it.  No special solders,
pastes, or glues.  Just a Weller, thin solder, and a magnifier over my
bifocals....  I think eventually it will be easier to obtain parts in SMT
formats.  I think you should be able to do a pretty cool job making protos
on the right kind of pretinned protoboard along with wirewrap wire
interconnects.  I haven't really had to make proto's with SMT stuff, but
if I had all the parts, a complete pcb-based "kit" should go pretty
smoothly.  I envision such a solution when the SSM/CEM chips dry up to
extinction, for all the older synths out there.  One of those little CNC
router-based pcb-makers should prove useful.


Barry

----------
From: 	KARLTO at INVALID.ED.NTNU.NO
Sent: 	Friday, January 15, 1999 11:07 AM
To: 	SYNTH-DIY at MAILHOST.BPA.NL
Subject: 	Re: day job


With the current discussions on soldering SMD components, I'd like to
point out that as long as you have a good tip on your soldering station,
a set of good pliers, a magnifying glass and a steady hand, you can
probably work with everything except ball-grid arrays. But then, these are
only used in the REALLY big processors, DSPs and FPGAs, so...





From vco at mindspring.com  Sat Jan 16 01:02:00 1999
From: vco at mindspring.com (tomg)
Date: Fri, 15 Jan 1999 19:02:00 -0500
Subject: Easytrax Resources
Message-ID: <yam7684.41.119689736@mail.mindspring.com>


Here's a short list of Easytrax stuff on the web. There's lots
out there.

EasyTrax V2.06 - easyfree.zip  515533  http://www.cirgraph.com/easyfree.zip   
                               

Ez Word doc - easyman.zip   106977 
http://www.seanet.com/~mcastelluccio/easyman.zip                       

Condensed Ez Doc - trax_man.pdf   53362 
http://pyramid.spd.louisville.edu/~cmdaug01/EE510/projects/trax_man.pdf

Ez Quick doc - easytrax.pdf   11087 
http://pyramid.spd.louisville.edu/~cmdaug01/EE510/projects/easytrax.pdf

Gerber view - gcprevue.zip  593360  http://www.cirgraph.com/gcprevue.zip      
                            

Gerber Convert - gerbcon.zip    74642 
http://www.apcircuits.com/html/gerbcon.zip                             


-tg

-------------------------------------------------
  Mad Mouse - PC Boards - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
-------------------------------------------------




From magnus at analogue.org  Sat Jan 16 01:56:02 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 16 Jan 1999 01:56:02 +0100
Subject: sneaking in a CMOS VCO
In-Reply-To: Your message of "Fri, 11 Apr 1997 12:44:30 +1000"
References: <1.5.4.32.19970411024430.00c7cdf0@popa.melbpc.org.au>
Message-ID: <199901160056.BAA28344@mail2.it.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 PP> At 09:32 PM 15/01/99 -0800, BJ wrote:
 >> 
 >> Well, how about "sneeking" in a CMOS VCO onto the wafer film then?
 >> 
 PP> Wow, this is what we need, 'Easter Eggs' in chips!
 PP> (to access the on-chip vocoder, hold all pins high for 30MS and toggle 
 PP> pin 5 three times)

 PP> paul perry, destroying productivity on fab lines world-wide

Hmm... and we are soon to ship our design to the fab... it's all
digital and it's not a analog process... but it would be fun.

There is allways the MOSIC processes available, that includes analog
chips. Hey, I could probably do this in Electric (an silicon layout
program).

Cheers,
Magnus



From stew at uq.net.au  Sat Jan 16 02:51:31 1999
From: stew at uq.net.au (Stewart Pye)
Date: Sat, 16 Jan 1999 12:51:31 +1100
Subject: FS: dead minimoog for $400 Australian
Message-ID: <199901160257.MAA29556@uq.net.au>

Hi all,

I have a dead minimoog for sale. I was going to restore it but am too busy
with other things at the moment so it's up for sale. Physically it is not
in really great shape. The front panel is pretty good so I was going to
f*ck the keyboard off and turn it into an obie expander kinda thing. 

$400 Australian

Regards,
Stewart Pye





From Colin.Fraser at scottishpower.plc.uk  Sat Jan 16 03:19:01 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Sat, 16 Jan 1999 02:19:01 -0000
Subject: MCS 70 (Memory Controlled Synthesizer)
Message-ID: <82880CC73125D211BC6800805F0D8307063B0180@catsprntp01.cat.scottishpower.plc.uk>

	-----Original Message-----
	From:	Tony Allgood [SMTP:oakley at techrepairs.freeserve.co.uk]
	Sent:	Saturday, January 16, 1999 7:43 PM
	To:	synth diy
	Subject:	Re: MCS 70 (Memory Controlled Synthesizer)


	There was a free single attactched to a copy of E&MM, I
	can't remember which one, but it was very cute. It sounded very
	analogue, in fact, on the free track it sounded like eight channels
of
	filtered square waves... blip blip blip bleep. Fast attack, short
decay
	notes like that bloody 'Pop Corn' shite from the 70s. However, this
was
	much better, a bit trancey. E&MM did a review on the album, and
thought
	it was too reliant on sequenced patterns, and so didn't rate it
much.
	Which is quite brave of them considering thay gave away a free
single
	and interviewed the fellow that same issue. Future Music are never
that
	honest.




I have that free single sitting in front of me right now - when I read this
mail I remembered last seeing it in the eighties in my pile of old singles.
It was still in the pile in the back of a cupboard - unplayed for well over
10 years. I can't even play it now as it won't fit in my CD or MD player ;-)

The label reads 'Lamborghini Records...   AXXESS, Extracts from the
Electronic Album Novels for the Moons'
It came out in 1984.
I'll see if I can get it into digital format. I remember liking it at the
time.

Colin f









From Colin.Fraser at scottishpower.plc.uk  Sat Jan 16 03:31:24 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Sat, 16 Jan 1999 02:31:24 -0000
Subject: Oscillator idea come's unstuck
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2BD@catsprntp01.cat.scottishpower.plc.uk>

Just before christmas a few of us discussed an idea of mine to use analogue
switches to change the polarity of a cap in an oscillator circuit instead of
discharging the cap - to allow a glitch free triangle wave, and to remove
the problems of using a reset circuit.

I built a simple proto-type before christmas, which I have now added an expo
convertor to, to try out with a keyboard cv.
Unfortunately, I can't get the oscillator to scale over more than an octave.
As far as I can see there is nothing wrong with the expo current source, so
I must assume that the analogue switches (4066) in the discharge path of the
capacitor are affecting the current in some way...
I don't know exactly what's going inside the 4066 so I can't really tell if
the problem is solvable, but it looks like the idea is no use for a musical
vco.

Oh well, it makes a good LFO at least...

Colin f




From zzynt at swipnet.se  Sat Jan 16 06:31:34 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 15 Jan 1999 21:31:34 -0800
Subject: 2SA798 - Cheap Dual Matched PNP Pair?
References: <852566F9.006ED8EA.00@galaxy.support.stream.com> <199901151144.UAA08790@smtp02.mail.gol.com>
Message-ID: <36A02436.5B4A@swipnet.se>

Minoru Yokoo wrote:
> 
> At 1:40 AM +0100 99.1.15, Rene Schmitz wrote:
> > At 12:12 14.01.99 -0800, you wrote:
> 
> > I wonder if there are datasheets (online) available for all this 2SA.. 2SC
> > japanese transistors, I bet there are quite a few interesting components
> > among these (see 2SC1583).
> 
> As far as I know, there aren't any "all-in-one" or useful online datasheets
> for Japanese transistors (I'm Japanese, so I've searched both in Japan and
> outside). You can find some at individual manufacturer's sites, but they
> usually only carry info for current models.
> 
> FYI, I've looked at a few ads and the 2SA798 is/was made by Mitsubishi and
> the going price in Tokyo is about 80 Yen per unit (about USD$0.75) or 6,000
> Yen (about USD$55) for a hundred. If you want to buy them in this price
> range, you can buy them here (and I don't work for them or anything, just
> looked up an ad):
> 
> Fujisho Denshi Co. Ltd
> Art Building 12-8 Shibuya 2 chome, Shibuya-ku, Tokyo 150-0002 Japan
> Ph 813-3499-0981
> Fx 813-3499-0251
> 
> Minoru

Thanks Minoru for your effort to tell us the prices of the device in
japan,
It is in every ones interest to know the prices of the same device 
at different locations around the globe.

At least one know how much money one was "ripped off" by the local
supplier! :)

BJ



From zzynt at swipnet.se  Sat Jan 16 06:32:04 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 15 Jan 1999 21:32:04 -0800
Subject: day job
References: <199901110738.IAA24854@window.intermetall.de>
Message-ID: <36A02454.EEB@swipnet.se>

Martin Czech wrote:
> 
> Back to work in 1999.
> 
> Happy new year for all!
> 
> I'm a design engineer at Micronas Intermetall, I design CMOS digital
> (sometimes also analog) circuits, mostly for controller ICs (6502 based).
> I also take care of the design of the companys ESD-protection structures.
> So far I worked only on little ICs, say 500.000 transistors, so one man,
> one IC, no team.
> 
> m.c.

Well, how about "sneeking" in a CMOS VCO onto the wafer film then?

BJ



From djblue at asu.edu  Sat Jan 16 08:36:33 1999
From: djblue at asu.edu (Reverend bluE)
Date: Sat, 16 Jan 1999 00:36:33 -0700 (MST)
Subject: question about an instrument
Message-ID: <Pine.GSO.3.96.990116003436.18287H-100000@general1.asu.edu>



My friend and I were reading Future Music Magazine and in an article about
ADD N to X  (I think was the name of the group) in one picture there was an
instrument that was circular shapped, and it appears that the name on it is
"Notron".  Does anybody have any info on this?  OH I think it was the december
issue of FM..
-b




From hugo.haesaert at skynet.be  Sat Jan 16 09:55:48 1999
From: hugo.haesaert at skynet.be (Hugo Haesaert)
Date: Sat, 16 Jan 1999 09:55:48 +0100
Subject: question about an instrument
In-Reply-To: <Pine.GSO.3.96.990116003436.18287H-100000@general1.asu.edu>
Message-ID: <199901160846.JAA29191@sunsoap.skynet.be>

Hi -b and all !

Long post this, but could give some inspiration too .  This will put the
info in the archives too :)

Re-forwarding a forwarded post, so DO NOT EMAIL ME about this .

Happy reading .


Keep 'em oscillating :)


Hugo
=

*******Quote*start***DO*NOT*EMAIL*ME*******************************


Date sent:      	Mon, 09 Nov 1998 10:31:24 -0600
To:             	analogue at hyperreal.org, digitalhell at resrocket.com,
       	user-forum at waldorf-gmbh.de, xpansions at synthcom.com
From:           	Mark Pulver <mpulver at midiwall.com>
Subject:        	[Digital_Hell] Notron Sequencer Info


This just showed up on the Nord Modular list... I figured that I'd forward
it around a bit...


** DO NOT REPLY TO ME **  ** DO NOT REPLY TO ME **  ** DO NOT REPLY TO ME
**

Reply to: Brana Gavrilovic <vgavrilo at direct.ca>

http://www.nscience.com (not up yet)



My name is Brana and I am involved with Latronic in North America. You are
able to order the units through me when and if you're interested.  In
comparison to something like Cubase, where the Notron shines is in the
real-time control area.  You have the use of many knobs, buttons and data
wheels for manipulating midi in ways nothing else can.  In addition, where
it is also useful is in the programming department.  It is quite easy to
add things like pitch and controller information at the step level.  If
you're drum module allows lets say decay, filter or tone to be controlled
via midi controllers, than that info can be inputted into the Notron so
that for example each bass step has a different pitch.  In addition, it
allows for happy accidents as it will coax sounds out of your gear that
you though were never possible due to the way it manipulates MIDI. Please
read below to get a sense of some of its features.


The company is currently  back ordered for about a month (I just hooked up
with them).  Also, I'll let you in on a little secret:  they're
re-designing the product and will be releasing a Notron 2 in January. 
Will look slightly different (will have a metal shell instead of the
current plastic one) but will be able to do everything the original one
can plus more.  There will undoubtedly be a waiting list for this one too,
so if you want one then let me know and I'll put you on it. Here's a
little bit of info + sales pitch I received from the Latronic people on
the original Notron.  If you have any questions just ask.  Pricing depends
on the exchange rate, but should be somewhere around $1050 US or $1,600
CDN (which includes all taxes and shipping).  Here goes:


"You may have already spotted that Notron is unlike other midi
controllers. We have dared to escape from the boring restrictions of black
box technology, and design something new, sexy and fun. Having spent years
suffering from the dry-eye and R.S.I. of constant sequencer abuse we
decided to find an alternate route to mouse driven music, something more
naturally intuitive. What we needed was a human-midi interface that even
the musically challenged could use to create agreeable new sounds, and yet
would still enable the professional musician to explore interesting fresh
territory. We also wanted an instrument that looked and felt good, knobs
that really made a difference, and lots and lots of flashing lights. We
wanted user-friendly control of midi information with instant response;
basically the ability to do immediately things that take forever with a
sequencer. It would manipulate the serious user?s midi data with fascist
precision yet take the phrase ?happy accident? to a new plateau. It would
make midi sounds behave more like analogue. This wondrous device would be
backwards compatible with existing midi sequencing set-ups,be able to
control or be controlled by them, and inject organic life into midi
composing. So here it is. Notron. The all singing all dancing Midi machine
that does all this and more. A new and exciting accessory matching your
musical career.

Aimed at both the amateur and professional musician and DJ, and perfect
for in-house soundtrack composition; Notron is a midi composing and
controlling instrument. It has 4 elements.

Each element has 16 steps (remember old drum machines ?) each step with
it?s own 3 colour LED.

Each element can be assigned a different midi channel, has it?s own
control wheel and knobs to adjust note numbers, velocity, notelength,
etc... basically any midi controller information can be applied manually
or automatically. All steps can also be individually adjusted with all the
above parameters.

All events can be controlled in real time. Notron can play sequences from
22 bpm to 220 bpm. (actually up to 1500 bpm but if you wanna go that fast
you'll need insurance.) Notron can also be slaved to permit complete midi
control of already recorded midi tracks, or for spontaneous live work.
Using a combination of 87 tri colour LEDs, 102 buttons and 14 Rotary
Controls Notron provides OVER SIXTY SERIOUSLY USEFUL FUNCTIONS, including:

1. NOTE CONTROL. All notes on all steps on all elements can be
individually set for pitch, velocity and length in real time.

2. EVENT PROGRAMMING. Events such as chords, strummed notes, transpose
events, pitch bend and controllers can be programmed on to any step on any
element. Highly textured combinations of notes/samples can be easily and
quickly created.

3. BEATWRAP. Automatically alters the pitch of a sample (usually drum
sample loop) to fit in exactly the same way as it is currently fitting in
the sequence to any new B.P.M. by pressing a key and rotating the tempo
wheel. On the fly!

4. SUPERSTEP. A unique feature which allows the user to place preset
waveforms onto the sequence to alter pitchbend, aftertouch or any other
controller, simultaneously if desired.  The presets can be fully
manipulated and customized in real time using control knobs.

5. SCALE ASSIGN. Assigns one of 32 preset scales to an element and then
transposes the sequence to play only correct notes within the key of that
scale.

6. REBOUND. Sets the chosen element to play its? sequence of notes/events
forwards then backwards.More interesting than it sounds on paper!

7. STRUM UP/DOWN. Plays the notes of a formed chord in a variety of
styles/speeds/direction via a key press.

8. SEQUENCE SHIFT. Allows the sequence of notes on the 4 elements to be
shifted relative to each other by any amount (within the chosen resolution
of the element/s) whilst the sequences are playing.

9. LOOP POINTS. The length of a sequence can easily be chosen to create
interesting timing cycles with other elements. 7/11 time ?...No problem.

10. ECHO. Up to 4 completely different echo settings can be applied at
once. They are always in time and can be altered in delay,repeats and
decay.

11. STEP OVERDRIVE. Sets a controllable amount of retriggering of a chosen
step. Incredible results on drum loop samples.

12. LOCKED STEPS. Stops a step from being altered while all around it can
be changed. eg; lock kick drum step then alter all others on element.

13. CONTROLLER WHEELS. The 4 element wheels can be assigned to affect
controller numbers, eg; panning, reverb, modulation and brightness (or any
other combination) and then applied in real time to the sequence. Can
produce mind bending results!

MUSICAL DIRECTION; We have found that users inevitably create the type of
music that THEY want to hear.

COMFORT; The unique shape of the casing enables the user to comfortably
operate the instrument from his or her lap. Get your feet up and relax
into it.

MEMORY; Work in progress?...save that Masterpiece. Patterns and Midi
setups can be saved internally, then chained for playback with
non-destructive sound manipulation.

PIN NUMBER SECURITY; Yep! If your Notron is stolen it will demand a unique
key sequence with over 10,000 permutations, or it will be completely
unusable. At least giving you the satisfaction that it can?t be used or
sold by the thieving ******!

NEW FUNCTIONS!!!
Sysex dump, Virtual Recording, More Scales, Kill Consecutives, Beatcreep:
human feel shuffle, Independent Echo, Midi Kill, Remote control, etc....

here's a few quotes:

"In the studio Notron took me on a voyage of discovery which has caused me
to reassess something I once firmly believed - namely, that no machine can
inspire... the Notron is wonderful." SOUND ON SOUND

"Using Notron like an analogue sequencer of old is FAB!"
FUTURE MUSIC

"This is the gadget I've been awaiting for years. Notron makes everything
tweakable on playback...create looping textures unlike anything you'd play
from a keyboard." SOUND ON SOUND

Anyone who says all music has already  been done obviously never had
a Notron."
ANDY HUGHES of THE ORB

The Latronic Notron is a sequencer that will inspire all who touch it to
experiment  with rhythm and explore tomorrows music." DJ MAGAZINE

"For trance, ambient or techno it's unbeatable - especially if you have
live performance in mind." MAKING MUSIC

"It's become an integral part of the studio here. I keep on trying to NOT
tell people about it - but I just can't help myself! It's a fantastic
machine." KEV at THE ORBIT CLUB

"It's a cross between a four-track sequencer and a very powerful MIDI
controller...the thing is just filled to bursting with capability. When I
finally hit the sack I had coloured lights flashing before my eyes and
wondrous new music ringing in my ears." MAKING MUSIC MAGAZINE

"I've used Notron on everything I've done since I got it!"
DJ CLAUDE YOUNG

"My new album is done ONLY using Notron - it's my only sequencer.
I've done ten tracks so far - two to go - it's a brilliant machine!
Also, all the singles I've done in the last 8 months have been on my
Notron."
DJ JAMES RUSKIN JANUARY 98

"We recently did a liveperformance using Notron into a couple of Nord
Leads which was really exciting and I'm now working with Sun Electric
using Notron which is very interesting." PRODUCER THOMAS FEHLMAN (BERLIN)

"I use Notron at the centre of my setup to get some really unexpected
sounds out of all sorts of synths. It's great for overdubbing percussive
passes because you can sync to existing tracks and add something
different." PRODUCER GARETH JONES at THE STRONGROOM LONDON


Brana Gavrilovic
vgavrilo at direct.ca
New Science Music
http://www.nscience.com


** DO NOT REPLY TO ME **  ** DO NOT REPLY TO ME **  ** DO NOT REPLY TO ME
**






From steve at babcom.u-net.com  Sat Jan 16 13:14:10 1999
From: steve at babcom.u-net.com (Steven Cook)
Date: Sat, 16 Jan 1999 12:14:10 +0000
Subject: MCS 70 (Memory Controlled Synthesizer)
References: <003e01be4188$a7b3f8e0$9e30883e@default>
Message-ID: <36A08292.A650FA11@babcom.u-net.com>

Hi,

Interesting! I have the LP, which has the distinction of being (presumably)
the only release on Lamborghini Records. The sleeve notes say:

"Direct mixed down from "Le Bart" (Made by Dipl. Inf. A. Bahrdt - Berlin)"

Definitely sounds like step time programming throughout.

Steve Cook.

Tony Allgood wrote:
> 
> Hi,
> 
> If I'm right, I think the guy who's behind it used to be the CEO for
> Lambourghini cars...(snip)
>
> Regards,
> 
> Tony Allgood, Cumbria, UK
> 
> e-mail: oakley at techrepairs.freeserve.co.uk
> 
> Rack mounted Moog VCF module. Details to be found at...
> 
> http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html




From jhaible at primus-online.de  Sat Jan 16 18:39:59 1999
From: jhaible at primus-online.de (jhaible)
Date: Sat, 16 Jan 1999 18:39:59 +0100
Subject: Oscillator idea come's unstuck
Message-ID: <19990116174208.13649.qmail@nuernberg2.pop.metronet.de>

> Just before christmas a few of us discussed an idea of mine to use
analogue
> switches to change the polarity of a cap in an oscillator circuit instead
of
> discharging the cap - to allow a glitch free triangle wave, and to remove
> the problems of using a reset circuit.
> 
> I built a simple proto-type before christmas, which I have now added an
expo
> convertor to, to try out with a keyboard cv.
> Unfortunately, I can't get the oscillator to scale over more than an
octave.
> As far as I can see there is nothing wrong with the expo current source,
so
> I must assume that the analogue switches (4066) in the discharge path of
the
> capacitor are affecting the current in some way...
> I don't know exactly what's going inside the 4066 so I can't really tell
if
> the problem is solvable, but it looks like the idea is no use for a
musical
> vco.
> 
> Oh well, it makes a good LFO at least...
> 
> Colin f

Hi Colin, and list, 

I was one of those who were excited about your idea, and I wasn't idle,
too.
I have tried some simulations with the scheme of the 4046 that Don has
pointed us to. 
All was fine as
long as I built the switches, current source etc. around the cap, and
forced
the switches on and off with an external clock. (Just to see the
waveforms).
But when I tried a real VCO configuaration with FETs as switches, the
waveforms
weren't smooth anymore. I have stopped at that point, but I think it has
something
to do with the way the switches are implemented, and the control signals of
the 
switches. What you want to avoid is two switches conducting at the same
time,
so maybe you need a short gap between the complementary control signals.
As I said, I stopped at this point but just because of lack of time.
(Finished
the HiFli, meanwhile ...)

Has anybody checked the signals on a 4046? Is the difference voltage
between
the two capacitor pins a true triangle or not ?

JH.



From oakley at techrepairs.freeserve.co.uk  Sat Jan 16 20:43:27 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Sat, 16 Jan 1999 19:43:27 -0000
Subject: MCS 70 (Memory Controlled Synthesizer)
Message-ID: <003e01be4188$a7b3f8e0$9e30883e@default>

Hi,

If I'm right, I think the guy who's behind it used to be the CEO for
Lambourghini cars. He commisioned the thing to be built for him. It had
no keyboard and was programmed in step time, since the owner couldn't
play a note. There was a free single attactched to a copy of E&MM, I
can't remember which one, but it was very cute. It sounded very
analogue, in fact, on the free track it sounded like eight channels of
filtered square waves... blip blip blip bleep. Fast attack, short decay
notes like that bloody 'Pop Corn' shite from the 70s. However, this was
much better, a bit trancey. E&MM did a review on the album, and thought
it was too reliant on sequenced patterns, and so didn't rate it much.
Which is quite brave of them considering thay gave away a free single
and interviewed the fellow that same issue. Future Music are never that
honest.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From tpaddock at seanet.com  Sat Jan 16 22:23:07 1999
From: tpaddock at seanet.com (Toby Paddock)
Date: Sat, 16 Jan 1999 13:23:07 -0800
Subject: day job
Message-ID: <01BE4153.5EB27FC0@d12.dialup.seanet.com>

I work in and maintain a vibration test lab.
Mostly aerospace, but sometimes more interesting
stuff like medical products or a nice big mixer.
There are a few parallels to audio gear.  The shaker is 
kind of like a speaker with an 18 inch voice coil and 20,000
pounds of push.  No cone, bummer.
The amplifier has about 1,000 water cooled transistors.
Also some EMI/EMC.

I have an embarrassingly undeveloped page about it at:
http://www.seanet.com/~tpaddock/vib_lab.html

Hoping this finds you,
Toby Paddock
- -- -  - -- -  - -- -  - -- -  - -- -
http://www.seanet.com/~tpaddock
Pronteon Approved, 
not A Study of Modern Residential Light Switches




From Zsolt.Homlokos at rz.ruhr-uni-bochum.de  Sat Jan 16 22:31:57 1999
From: Zsolt.Homlokos at rz.ruhr-uni-bochum.de (Zsolt Homlokos)
Date: Sat, 16 Jan 1999 22:31:57 +0100
Subject: Synth-DIY=dead??
References: <19990116174208.13649.qmail@nuernberg2.pop.metronet.de>
Message-ID: <36A1054D.147C82DE@rz.ruhr-uni-bochum.de>

is synth DIY dead at the moment ?
i couldnt say too much at the moment to a discussion but i would like to learn
of YOUR discussions.
well is there any "easy" MS10 or MS20 mod?
bye and keep on discussing .........:)
Zsolt




From varner at k-online.com  Sun Jan 17 00:24:15 1999
From: varner at k-online.com (Steve Varner)
Date: Sat, 16 Jan 1999 15:24:15 -0800
Subject: KE4859
Message-ID: <36A11F99.BAC99416@k-online.com>

What do I use for the KE4859 FET in the Electronotes VCO (ENS-76 VCO
Option 1)?

I assume this is the same as the 2N4859 and PN4859 as they are mentioned
in the text.
I want something that works the same as this N-channel JFET analog
switch, but which I can get easily in the U.S. (Radio Shack, Mouser,
Jameco, Digi-Key, etc.).

I found this PDF file:
http://www.siliconix.com/www/data/smallfet/70244.pdf




From edusilva at bahianet.com.br  Sun Jan 17 01:17:28 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 16 Jan 1999 22:17:28 -0200
Subject: Synth-DIY=dead??
Message-ID: <199901170019.WAA17879@postman.bahianet.com.br>

> De: Zsolt Homlokos <Zsolt.Homlokos at rz.ruhr-uni-bochum.de>
> Para: jhaible at metronet.de; 'synth-diy at mailhost.bpa.nl'
> Assunto: Synth-DIY=dead??
> Data: S?bado, 16 de Janeiro de 1999 19:31
> 
> is synth DIY dead at the moment ?

No (I hope)

> i couldnt say too much at the moment to a discussion but i would like to
learn
> of YOUR discussions.

Try something.

> well is there any "easy" MS10 or MS20 mod?

Good! I found sometihng here:

http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/

> bye and keep on discussing .........:)
> Zsolt

OK

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil





From magnus at analogue.org  Sun Jan 17 01:33:33 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 17 Jan 1999 01:33:33 +0100
Subject: day job
In-Reply-To: Your message of "Sat, 16 Jan 1999 13:23:07 -0800"
References: <01BE4153.5EB27FC0@d12.dialup.seanet.com>
Message-ID: <199901170033.BAA06362@mail2.it.kth.se>

>>>>> "TP" == Toby Paddock <tpaddock at seanet.com> writes:

 TP> I work in and maintain a vibration test lab.
 TP> Mostly aerospace, but sometimes more interesting
 TP> stuff like medical products or a nice big mixer.
 TP> There are a few parallels to audio gear.  The shaker is 
 TP> kind of like a speaker with an 18 inch voice coil and 20,000
 TP> pounds of push.  No cone, bummer.
 TP> The amplifier has about 1,000 water cooled transistors.
 TP> Also some EMI/EMC.

Hmm, this would surely make a neat sub-base. Set it up with a 6 Hz
sinewave, sit down on it and save yourself a ride on the ammusement
park. As you hit the self-resonance you would basically go accutely
very sick and damn yourself for comming up with this idea. It could
also be a very cruel prank on a colleague, but I advice against such
things.

	Shake it oh baby now...

Cheers,
Magnus



From magnus at analogue.org  Sun Jan 17 02:47:37 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 17 Jan 1999 02:47:37 +0100
Subject: Oscillator idea come's unstuck
In-Reply-To: Your message of "Sun, 17 Jan 1999 01:19:33 -0800"
References: <36A1AB25.255A@swipnet.se>
Message-ID: <199901170147.CAA15468@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> jhaible wrote:
 >> Has anybody checked the signals on a 4046? Is the difference voltage
 >> between
 >> the two capacitor pins a true triangle or not ?
 >> 
 >> JH.

 B> Its not!
 B> It seems that you have missed BJ's and Magnus Daniellsons discussions
 B> on the 4046 pll!

Hey, I was about to say that... but you got there before me ;)

 B> Sorry to say, but the signals on each side of the cap is out of
 B> phase and only a half period sawtoot.Therefore you can not get 
 B> a true tri wave just by subtracting the waves.

 B> What you get in a subtraction is a half the wave tri and half the wave
 B> square.

 B> Looks like this:(well how about your gif proposal again?)

  
 B>    /l      /l
 B>   / l     / l
 B>  /  l    /  l
 B> /   l   /   l 
 B>     l   l
 B>     \   l
 B>      \  l
 B>       \ l
 B>        \l

This is correct.

The clue to how this waveform really comes together as it does is
hidden in a RCA application note ICAN-6101 (it is still a very valid
application note on how the 4046 works). On each end of the capacitor
there is one pair of N and P type MOSFETs and a inverter input to the
VCO state machine. When the loading one end of the cap is "hooked" to
earth via the N-channel MOSFET of that end and the other is beeing
feed with a load current via the P-channel MOSFET over in that
end. This load current comes from a P-channel MOSFET-pair acting as a
current mirror. When the voltage reaches the threshold (set by the
CMOS midpoint at 1/2 the Vdd-Vss voltage) the state-machine flips, it
now hooks the previous load point (now having the high voltage end of
the cap) to earth and the previous ground point (now having a low
voltage) to the load current. This will cause the previous ground
point to actually be negative, this is not a place you would want a
input to a CMOS logic and therefore there is a input protection diode
up to earth (there are more of those, but they are not used actively
in the curcuit) so now will the capacitor quickly uncharge via the
protection diode. When the capacitor is empty the loading current will
be in full charge and start loading that end.

In BJ's and mine discussion thread before I forgot the protection
diode discharing the cap. However, the curcuit would work if the
capacitor was not discharged to ground by the input diode, but the
input stage would lock up in the parasitic SCR mode and burn the hell
out of the 4046.

One could take inspiration from the 4046 VCO to make one that does
have a triangular wave. Note that the 9046 has a much improved
stability for supply voltage as well as many other benefits. They use
op-amps instead of 1-fet source followers (the pin 9 VCO input looks
into the gate of a N-channel MOSFET acting in emitter follower action) etc.

The signals are 180 degree out of phase in respect to each other.

 B> Difficult to do a asci of the wave!!

It certainly is, but equations mostly come out pretty readable.
On the other hand, I prefer TeX/LaTeX for equations.

 B> It looks like a "monster chain sawtooth wave" sort of.

Ugh. Yeah.

Cheers,
Magnus



From aschrock at cs.brandeis.edu  Sun Jan 17 03:40:02 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 16 Jan 1999 21:40:02 -0500 (EST)
Subject: Synth-DIY=dead??
In-Reply-To: <36A1054D.147C82DE@rz.ruhr-uni-bochum.de>
Message-ID: <Pine.HPP.3.95.990116213754.18990A-100000@bay.cs.brandeis.edu>

On Sat, 16 Jan 1999, Zsolt Homlokos wrote:
> is synth DIY dead at the moment ?

Aw crap! And I've been wasting all this time putting together synths. Off
to the dumpster with 'em. 

> i couldnt say too much at the moment to a discussion but i would like to learn
> of YOUR discussions.
> well is there any "easy" MS10 or MS20 mod?

No, but then again, what do you expect from a 'dead' profession. 

Andrew
insert tongue in cheek 

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|







From stew at uq.net.au  Sun Jan 17 05:29:45 1999
From: stew at uq.net.au (Stewart Pye)
Date: Sun, 17 Jan 1999 15:29:45 +1100
Subject: FS: dead minimoog for $400 Australian**SOLD**
In-Reply-To: <199901160257.MAA29556@uq.net.au>
Message-ID: <199901170535.PAA21345@uq.net.au>

The minimoog has been sold to someone in adelaide.

Thanks,

Stewart Pye




From afas at git.com.au  Sun Jan 17 06:04:34 1999
From: afas at git.com.au (geoffery francis james)
Date: Sun, 17 Jan 1999 13:04:34 +0800
Subject: sci sixtrack
Message-ID: <199901170506.NAA09099@defiant.git.com.au>

could someone please provide the url for the above.
regards
geoff james



From chordman at flash.net  Sun Jan 17 07:07:05 1999
From: chordman at flash.net (Scott Gravenhorst)
Date: Sun, 17 Jan 99 07:07:05
Subject: Oscillator idea come's unstuck
Message-ID: <199901171504.JAA22049@echo.flash.net>

This looks like a triangle summed with a square wave.  Couldn't the
triangle be derived by subtracting the oscillator's square output?  I
would suspect that it should be in phase with this.

>>    /l      /l
>>   / l     / l
>>  /  l    /  l
>> /   l   /   l 
>>     l   l
>>     \   l
>>      \  l
>>       \ l
>>        \l



-- Scott Gravenhorst
-- RedWebMail by RedStarWare (srg)
-- FatMan Site: www.teklab.com/~chordman
-- Linux Rex, Linux Vobiscum





From zzynt at swipnet.se  Sun Jan 17 10:19:33 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 17 Jan 1999 01:19:33 -0800
Subject: Oscillator idea come's unstuck
References: <19990116174208.13649.qmail@nuernberg2.pop.metronet.de>
Message-ID: <36A1AB25.255A@swipnet.se>

jhaible wrote:

> Has anybody checked the signals on a 4046? Is the difference voltage
> between
> the two capacitor pins a true triangle or not ?
> 
> JH.

Its not!
It seems that you have missed BJ's and Magnus Daniellsons discussions
on the 4046 pll!

Sorry to say, but the signals on each side of the cap is out of
phase and only a half period sawtoot.Therefore you can not get 
a true tri wave just by subtracting the waves.

What you get in a subtraction is a half the wave tri and half the wave
square.

Looks like this:(well how about your gif proposal again?)

  
   /l      /l
  / l     / l
 /  l    /  l
/   l   /   l 
    l   l
    \   l
     \  l
      \ l
       \l

Difficult to do a asci of the wave!!
It looks like a "monster chain sawtooth wave" sort of.

BJ



From jhaible at primus-online.de  Sun Jan 17 11:05:24 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 17 Jan 1999 11:05:24 +0100
Subject: Oscillator idea come's unstuck
Message-ID: <19990117101005.27113.qmail@nuernberg2.pop.metronet.de>

> Its not!
> It seems that you have missed BJ's and Magnus Daniellsons discussions
> on the 4046 pll!

You're right. Sorry about that. I saw a portion of this, but didn't
associate it with the triangle VCO.


>    /l      /l
>   / l     / l
>  /  l    /  l
> /   l   /   l 
>     l   l
>     \   l
>      \  l
>       \ l
>        \l

Now that looks familiar from my simulations, too ...

JH.




From jhaible at primus-online.de  Sun Jan 17 11:09:11 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 17 Jan 1999 11:09:11 +0100
Subject: MS-20 Mods
Message-ID: <19990117101006.27113.qmail@nuernberg2.pop.metronet.de>

> well is there any "easy" MS10 or MS20 mod?

Good! I found sometihng here:

http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/


Modifying an MS-20 is easy from the circuit's point of view, but it's a
pain
mechanically. You have to unscrew all the potentiometers to get the pcb in
your hands.

JH.



From edusilva at bahianet.com.br  Sun Jan 17 13:18:33 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sun, 17 Jan 1999 10:18:33 -0200
Subject: MS-20 Mods
Message-ID: <199901171225.KAA14374@postman.bahianet.com.br>

Who was the fellow who pulled out the noisy MS20 VCA and stuffed a SSM
inside?

Edu
----------
> De: jhaible <jhaible at primus-online.de>
> Para: 'synth-diy at mailhost.bpa.nl'
> Assunto: MS-20 Mods
> Data: Domingo, 17 de Janeiro de 1999 08:09
> 
> > well is there any "easy" MS10 or MS20 mod?
> 
> Good! I found sometihng here:
> 
> http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/
> 
> 
> Modifying an MS-20 is easy from the circuit's point of view, but it's a
> pain
> mechanically. You have to unscrew all the potentiometers to get the pcb
in
> your hands.
> 
> JH.



From Zsolt.Homlokos at rz.ruhr-uni-bochum.de  Sun Jan 17 15:27:15 1999
From: Zsolt.Homlokos at rz.ruhr-uni-bochum.de (Zsolt Homlokos)
Date: Sun, 17 Jan 1999 15:27:15 +0100
Subject: MS 20 PWM??!!
References: <199901171225.KAA14374@postman.bahianet.com.br>
Message-ID: <36A1F342.2C2B1FC7@rz.ruhr-uni-bochum.de>

hello,
i just figured that the PWM sometimes affects the sound though no square wave

is switched,how is that possible????
especially together with RingModulation.....
thanks
Zsolt




From 104065.2340 at compuserve.com  Sun Jan 17 17:26:24 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sun, 17 Jan 1999 11:26:24 -0500
Subject: Japanese semi data
Message-ID: <199901171126_MC2-66F7-8B8A@compuserve.com>

Message text written by Paul Perry
>There are a series of books, 15cm high & 21cm wide, 
published in Asia by Tech Publications PTE,LTD Singapore

which are reprints of ones from
ECA Electronic GmbH Germany

the list includes
Japanese Transistor Substitution Manual
<

Hi Paul:

This sounds like a set of 4 soft cover books I bought a few years ago from
MCM Electronics (800) 543-4330.  The books are titled:

The Diode Manual
The FET Manual
The Transistor Manual
The Transistor Substitution Manual

The books are mostly printed in Japanese, but the numerical information,
along with the heading of eack column of device specs are written in
English, making them usable to someone familiar with semicondoctor data
sheets, but not able to read Japanese.  The book set covers nearly every
discrete Japanese semiconductor I've come across.  Highly recommended, and
affordable, I remember they cost about $10 - $15 each.

Most Japanese devices are also listed in the D.A.T.A. series of books, but
these are quite expensive, around $600 I think.  I bought a D.A.T.A. set at
a ham fest for a few dollars a while back.

I also got free semiconductor catalogs from Toshiba, Sony, Shindengen, Rohm
and some of the other Japanese manufacturers by calling their U. S. sales
offices and asking for whatever they have.

If anyone on the diy list wants info on a Japanese part and can't find it,
e-mail me and I'll see if I have it.

Terry Michaels



From 104065.2340 at compuserve.com  Sun Jan 17 17:33:04 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Sun, 17 Jan 1999 11:33:04 -0500
Subject: 2SA798 - Cheap Dual Matched PNP Pair?
Message-ID: <199901171133_MC2-66F7-8BEC@compuserve.com>

Message text written by Rene Schmitz
>I wonder if there are datasheets (online) available for all this 2SA.. 2SC
japanese transistors, I bet there are quite a few interesting components
among these (see 2SC1583).
I've tried to search questlink but with little success.
Anyone knows who manufactures these?

Rene
<

Hi Rene:

the 2SC1583 is made by Mitsubishi.

Terry Michaels



From THEKn0TiS at aol.com  Sun Jan 17 18:50:05 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Sun, 17 Jan 1999 12:50:05 EST
Subject: hs 60 vcf/gate in mod questions
Message-ID: <f489bb6d.36a222cd@aol.com>

i emagine if i wanted to controll my juno hs60 with vcf and gate in
modifications i would have to put jack inputs on the front pannle routed to
what ><>?? the 80017A vfc/vca chip's<>??? where would i put the gate
input<>><...,.. any help would be most greatfully appritiated



From synth1 at airmail.net  Sun Jan 17 18:52:16 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 17 Jan 1999 11:52:16 -0600
Subject: Great US catalog for tools
Message-ID: <001101be4242$1f150aa0$fcdbfea9@p400>

For those of you in the US, Techi-Tools has their new catalog out.
Drool-factor = 10.
If you like 1-stop shopping for hand tools, test equipment/leads, chemicals,
solder/de-solder stations, etc etc etc this is the catalog to have.

1-800-832-4866
www.techni-tool.com

The prices are "middle-of-the-road". I use their wire strippers every day. I
wear out 2
pairs a year, but at $9 who cares???

Paul Schreiber
Synthesis Technology





From edusilva at bahianet.com.br  Sun Jan 17 20:24:19 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sun, 17 Jan 1999 17:24:19 -0200
Subject: MCS 70 (Memory Controlled Synthesizer)
Message-ID: <199901171925.RAA08444@postman.bahianet.com.br>

Replying my own mail...

> "Music and sounds conceived, arranged and played by Romano Mussumara and
> Claudio Gizzi. All tunes realized entirely with sounds programmed by
Mario
> Maggi using the MCS70 (Memory Controlled Synthesizer). Sound engineer:
> Luciano Torani."
 
Mario Maggi designed (among others) the Elka Synthex, maybe the best
Italian synth.
	http://www.synthmuseum.com/elka/elksyn01.html

Claudio Gizzi is an horror film soundtrack composer.
	http://www.geocities.com/~scorelogue/vivaitalia.html

About the MCS70...
	http://members.aol.com/widegauge/filmog/mcs70.html

Steven Cook wrote:

(snip)
> Interesting! I have the LP, which has the distinction of being >
(presumably)
> the only release on Lamborghini Records.
(snip)

No, Samantha Fox had two singles released by Lamborghini Records in the
early 80's.

Tony Allgood wrote:

> E&MM did a review on the album, and thought
> it was too reliant on sequenced patterns, and so didn't rate it much.
> Which is quite brave of them considering thay gave away a free single
> and interviewed the fellow that same issue.

Can I see this interview, please?

Edu



From mirwin1 at istar.ca  Sun Jan 17 20:49:46 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Sun, 17 Jan 1999 14:49:46 -0500
Subject: Pre-distortion Diodes for Moog Ladder Filter
Message-ID: <36A23EDA.B2476444@istar.ca>

Hi,
Has anyone thought about or tried adding linearizing diodes to the audio
input of a Moog VCF ? This would be similar to the predistortion circuit
used in the CA3280 and LM13600. Presumably this could be used to change
the filter performance from the traditional warm-sounding gentle
distortion ( with plenty of background hiss ) to a cleaner, higher
signal-noise ratio mode ( more like other VCF's). It would be neat to be
able to switch between these two modes.




From borg0 at jps.net  Sun Jan 17 20:59:12 1999
From: borg0 at jps.net (Debby and Gene Stopp)
Date: Sun, 17 Jan 1999 11:59:12 -0800
Subject: KE4859
Message-ID: <000b01be4255$fdb1e4a0$20c4edd0@oemcomputer>

I have found that the NTE cross reference part works perfectly in the ENS-76
VCO Option 1. The number is NTE-466. You can find the NTE catalog parts at a
lot of electronics stores. I just bought 8 of these at Fry's Electronics for
a couple bucks each.

I think that this part, along with the LM311 and the tempco, put this VCO
into the catagory of "made from almost but not quite easy to obtain parts".
However I believe that it's really the best VCO you can make for the effort.

A close second would be the 3080-based tri-square EN-76 VCO (I forget the
option number, it's the one with the 3080 integrator and the 3080 schmitt
trigger). You have to do a little more building to get a sawtooth out of it,
but the triangle is really pristine. It has the same kind of expo converter
except the trannys are PNP rather than NPN, and the same tempco
requirements. If you have a way to get 3080's easily, this VCO would fall
into the catagory of "made from easy to obtain parts". Except for that
stinkey tempco.

- Gene


-----Original Message-----
From: Steve Varner <varner at k-online.com>
To: synth-diy <synth-diy at mailhost.bpa.nl>
Date: Saturday, January 16, 1999 4:25 PM
Subject: KE4859


>What do I use for the KE4859 FET in the Electronotes VCO (ENS-76 VCO
>Option 1)?
>
>I assume this is the same as the 2N4859 and PN4859 as they are mentioned
>in the text.
>I want something that works the same as this N-channel JFET analog
>switch, but which I can get easily in the U.S. (Radio Shack, Mouser,
>Jameco, Digi-Key, etc.).
>
>I found this PDF file:
>http://www.siliconix.com/www/data/smallfet/70244.pdf
>
>




From squarewave at jps.net  Sun Jan 17 21:19:18 1999
From: squarewave at jps.net (Debby and Gene Stopp)
Date: Sun, 17 Jan 1999 12:19:18 -0800
Subject: KE4859
Message-ID: <002a01be4256$c3dcca00$20c4edd0@oemcomputer>

I have found that the NTE cross reference part works perfectly in the ENS-76
VCO Option 1. The number is NTE-466. You can find the NTE catalog parts at a
lot of electronics stores. I just bought 8 of these at Fry's Electronics for
a couple bucks each.

I think that this part, along with the LM311 and the tempco, put this VCO
into the catagory of "made from almost but not quite easy to obtain parts".
However I believe that it's really the best VCO you can make for the effort.

A close second would be the 3080-based tri-square EN-76 VCO (I forget the
option number, it's the one with the 3080 integrator and the 3080 schmitt
trigger). You have to do a little more building to get a sawtooth out of it,
but the triangle is really pristine. It has the same kind of expo converter
except the trannys are PNP rather than NPN, and the same tempco
requirements. If you have a way to get 3080's easily, this VCO would fall
into the catagory of "made from easy to obtain parts". Except for that
stinkey tempco.

- Gene

-----Original Message-----
From: Steve Varner <varner at k-online.com>
To: synth-diy <synth-diy at mailhost.bpa.nl>
Date: Saturday, January 16, 1999 4:25 PM
Subject: KE4859


>What do I use for the KE4859 FET in the Electronotes VCO (ENS-76 VCO
>Option 1)?
>
>I assume this is the same as the 2N4859 and PN4859 as they are mentioned
>in the text.
>I want something that works the same as this N-channel JFET analog
>switch, but which I can get easily in the U.S. (Radio Shack, Mouser,
>Jameco, Digi-Key, etc.).
>
>I found this PDF file:
>http://www.siliconix.com/www/data/smallfet/70244.pdf
>
>




From magnus at analogue.org  Sun Jan 17 21:28:25 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 17 Jan 1999 21:28:25 +0100
Subject: Pre-distortion Diodes for Moog Ladder Filter
In-Reply-To: Your message of "Sun, 17 Jan 1999 14:49:46 -0500"
References: <36A23EDA.B2476444@istar.ca>
Message-ID: <199901172028.VAA20982@mail2.it.kth.se>

>>>>> "MBI" == Michael B Irwin <mirwin1 at istar.ca> writes:

 MBI> Hi,
 MBI> Has anyone thought about or tried adding linearizing diodes to the audio
 MBI> input of a Moog VCF ? This would be similar to the predistortion circuit
 MBI> used in the CA3280 and LM13600. Presumably this could be used to change
 MBI> the filter performance from the traditional warm-sounding gentle
 MBI> distortion ( with plenty of background hiss ) to a cleaner, higher
 MBI> signal-noise ratio mode ( more like other VCF's). It would be neat to be
 MBI> able to switch between these two modes.

Well, I have considered these diodes, only to figure out that they
would probably not really help all that much. They would help to
compensate for the tanh distorsion of the input transistor pair.

However, this is not the same as compensating the distorsion of the
transistors higher up in the ladder. In Dr. Moog's filterpatent it is
clearly stated that the signal level is kept so that the signal
current is much lower than the modulation current in order to keep
distorsion down. What happends is that the signal will not only
experience direct distorsion, but also modulate the poles in the
filter. This is a non-linear filter responce, but it may be nice to
the ear.

I am not sure that one should spend time to get the Moog ladder
approximate other filters and why should it? You could build that
other filter directly instead. There is surely stuff to do with the
Moog ladder, but is it really the things to move it into the line
sonically with the others?

I have been spending some time in figuring out how to set the zeros to
various points, now I know how to do that. I have also been thinking
of what can be done with various pole placements, but there is more
homework to do on that. This is only part of the small-signal models,
I haven't spent time doing large-signal models.

There are however some people experimenting alot with various ladders
that has had great success in there experiments and I expect more to
come out of that work.

Cheers,
Magnus



From smart at nn.com  Sun Jan 17 23:30:49 1999
From: smart at nn.com (Mark Smart)
Date: Sun, 17 Jan 1999 16:30:49 -0600 (EST)
Subject: PAIA Hex VCA circuit
Message-ID: <199901172230.QAA17493@medusa.nn.com>

Hi everyone.

After forgetting about it for a year and a half, I have dived back into my
GR-300 guitar synth hacking project. I have been messing with this circuit
invented by PAIA which uses a 4049 CMOS chip to create six VCA's which mix
into one output  (the output comes out the ground pin!). What I'm using
this for is to mix together pulse and square waves derived from the
GR-300's internal sawtooth waveform. My saw-to-pulse converter and octave
dividers create three pulse waves which oscillate between 0 and +15 volts.

This circuit mostly works execpt that there is noticeable leakage between
channels which is especially bad at low volumes. I have three
signals, the pulse wave, the /2 square wave, and the /4 square wave. When
you turn on the control voltage for the /4 square wave, it comes on, but
with a noticeable amount of the /2 and pulse signals leaking in. I would
appreciate the advice of anyone who is familiar with this PAIA hex VCA
circuit. I could also post a schematic at some point maybe. I tried
lowering the 4.7 Meg resistors to 2.2 Meg, and this helped some, but did
not eliminate the problem. My biggest problem in debugging the circuit is
that I really don't understand how it works very well. The description
which came with it does not go into that much detail. It does not specify a
limit on CV or audio voltage ranges. The basic idea of the circuit is that
the FET's in the CMOS inverter gate are used as voltage-controlled
resistors, and somehow the audio inputs mix inside the chip and come out
the ground pin.

I would appreciate any advice. Also thanks to the people on the list who
have helped me in the past in my sporadic forays into synth-building. 


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     And Musician                             *
*     smart at medusa.nn.com                      *
************************************************



From magnus at analogue.org  Sun Jan 17 23:58:13 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 17 Jan 1999 23:58:13 +0100
Subject: Pre-distortion Diodes for Moog Ladder Filter
In-Reply-To: Your message of "Sun, 17 Jan 1999 18:41:05 -0500"
References: <36A27510.60D7B257@istar.ca>
Message-ID: <199901172258.XAA21771@mail2.it.kth.se>

>>>>> "MBI" == Michael B Irwin <mirwin1 at istar.ca> writes:

 MBI> Magnus,
 MBI> Thanks for your helpful advice.

Well, anytime. You can also see it as I do my part to keep the
confusion up (or was it down, I could never tell) ;)

 MBI> Is the major source of distortion in the Moog ladder (under
 MBI> normal operating conditions) distortion from the input
 MBI> differential amp stage or distortion due to instantaneous 
 MBI> modulation of the filter cutoff frequency by the audio signal?

Well, I haven't done any real measurements or simulations, but if you
ask for my gut-feeling guess I'd say that the non-linear modulation of
the poles migth in itself not be that important, but it is certainly
there.

 MBI> If the signal-induced modulation is the dominant effect, it would be
 MBI> interesting to take a 24 dB/oct OTA VCF and feed some of the audio
 MBI> output back into a control voltage input in an attempt to produce a
 MBI> controllable amount of warm-sounding distortion in a low-noise VCF.

There is just one way to learn, try it!

Personally I don't think this is the most important non-linearity, I
would say that the tanh/ln distorsion in combination with the linear
filtering effect accounts for much of what is going on. See it as my
current theory, nothing more. There are people that has done much more
homework than I have, I leave this to them.

Cheers,
Magnus



From uzs159 at uni-bonn.de  Mon Jan 18 00:05:05 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Mon, 18 Jan 1999 00:05:05 +0100
Subject: Oscillator idea come's unstuck
Message-ID: <3.0.5.32.19990118000505.008be100@ibm.rhrz.uni-bonn.de>

At 02:31 16.01.99 -0000, you wrote:
>Just before christmas a few of us discussed an idea of mine to use analogue
>switches to change the polarity of a cap in an oscillator circuit instead of
>discharging the cap - to allow a glitch free triangle wave, and to remove
>the problems of using a reset circuit.
>
>I built a simple proto-type before christmas, which I have now added an expo
>convertor to, to try out with a keyboard cv.
>Unfortunately, I can't get the oscillator to scale over more than an octave.
>As far as I can see there is nothing wrong with the expo current source, so
>I must assume that the analogue switches (4066) in the discharge path of the
>capacitor are affecting the current in some way...
>I don't know exactly what's going inside the 4066 so I can't really tell if
>the problem is solvable, but it looks like the idea is no use for a musical
>vco.
>
>Oh well, it makes a good LFO at least...
>
>Colin f
>

I don't want to discourage anyone, but either its that the two switches are
conducting simultaneously. (as J?rgen said)
But I suspect another thing: I've read in Horowitz & Hill Chapter 3.12
"Limitations of FET switches", that some (and they mention the 4066) analog
switches have the nasty property to short (!) the input to ground
momentarily. 
If that might happen, then the charge would leak to ground.
I would try it with a 4016 which is different to 4066.

Apart from this it might could be that the R(on) of the switch varies with
the voltage on its inputs. The 4066 is better in this regard than the 4016. 

Bye
 Rene



             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From magnus at analogue.org  Mon Jan 18 00:15:14 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 18 Jan 1999 00:15:14 +0100
Subject: Oscillator idea come's unstuck
In-Reply-To: Your message of "Sun, 17 Jan 1999 23:04:41 -0800"
References: <36A2DD09.60AA@swipnet.se>
Message-ID: <199901172315.AAA22005@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> Scott Gravenhorst wrote:
 >> 
 >> This looks like a triangle summed with a square wave.  Couldn't the
 >> triangle be derived by subtracting the oscillator's square output?  I
 >> would suspect that it should be in phase with this.
 >> 
 >> >>    /l      /l
 >> >>   / l     / l
 >> >>  /  l    /  l
 >> >> /   l   /   l
 >> >>     l   l
 >> >>     \   l
 >> >>      \  l
 >> >>       \ l
 >> >>        \l
 >> 
 >> -- Scott Gravenhorst
 >> -- RedWebMail by RedStarWare (srg)
 >> -- FatMan Site: www.teklab.com/~chordman
 >> -- Linux Rex, Linux Vobiscum

 B> No i dont think soo, because the saw is twice the 
 B> frequency of the square!

We better make a square of the right frequency then. I think we have
found the source for BJ's and mine 90/180 degree disagreement. We are
just thinking in two diffrent frequencies. I knew there where
something banal about it.

 B> But another interesting thing is the clean and nice PWM
 B> you gett when driving the saw thru the xor gate.

 B> And another interesting thing is the "fixed" frequency
 B> and the "second" phase pulse pointing of the xor gate
 B> when you are sending the saw to both of the xor gate
 B> input pins.

 B> If yo do so then you get a short output pulse at pin 1 (i think)
 B> at the frequency of the saw and as you warying the
 B> PW (dc shift) of the saw there appers another short pulse
 B> in the pulse train.This pulse moves from ether side of
 B> the stable pulse trains outher limits.

 B> (Ooh dear, what this was difficult for me to explain!!!)

I think I got that.

 B> I have no idea on what one would use this for!!:)

It does sound a bit wierd (that is, we have yeat to find it the most
usefull thing invented ;)

 B> Plashe plonting plotter plablpthpthpfftp!!!

Ehh... service bullentine:

BJ down for service. After fixing the pthpfftp-bug, a standard
procedure, BJ will be rebooted for your convenience and further
enligthment of life. Please stand by while I adjust the magocrapial
translator banks.

Meanwhile Magda is down for extensive and long overdue
rewiring. Expect no service for the comming 18 hours.

You non-average SyS-OP,
Kork-Orvar



From magnus at analogue.org  Mon Jan 18 00:29:01 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 18 Jan 1999 00:29:01 +0100
Subject: Oscillator idea come's unstuck
In-Reply-To: Your message of "Mon, 18 Jan 1999 00:16:51 -0800"
References: <36A2EDF3.7420@swipnet.se>
Message-ID: <199901172329.AAA22065@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> plablpthpthpfftp plablpthpthpfftp plablpthpthpfftp....Phhhhasaaaaseee...

 B> Phaaase, phase, in phase again, ho hum! beeep!

Ah.... that's it.

 >> We better make a square of the right frequency then. I think we have
 >> found the source for BJ's and mine 90/180 degree disagreement. We are
 >> just thinking in two diffrent frequencies. I knew there where
 >> something banal about it.

 B> Well thats solve our problem i think (after rebooted BJ)!

Good.

BTW, I enjoyed reading about that PAIA 4069UB trick, I can imagine how
it would work without schematic, it's a *crude* trick, but I like it
that way ;)

Cheers,
Magnus (5 min to shut-up oh, shut-down, eh... either way actually)



From mirwin1 at istar.ca  Mon Jan 18 00:41:05 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Sun, 17 Jan 1999 18:41:05 -0500
Subject: Pre-distortion Diodes for Moog Ladder Filter
References: <36A23EDA.B2476444@istar.ca> <199901172028.VAA20982@mail2.it.kth.se>
Message-ID: <36A27510.60D7B257@istar.ca>

Magnus,
Thanks for your helpful advice. Is the major source of distortion in the
Moog ladder (under normal operating conditions) distortion from the
input differential amp stage or distortion due to instantaneous
modulation of the filter cutoff frequency by the audio signal? If the
signal-induced modulation is the dominant effect, it would be
interesting to take a 24 dB/oct OTA VCF and feed some of the audio
output back into a control voltage input in an attempt to produce a
controllable amount of warm-sounding distortion in a low-noise VCF.




From costello at seanet.com  Mon Jan 18 01:29:01 1999
From: costello at seanet.com (Sean Costello)
Date: Sun, 17 Jan 1999 16:29:01 -0800
Subject: Subsonic Death Rays (was Re: day job)
References: <01BE4153.5EB27FC0@d12.dialup.seanet.com> <199901170033.BAA06362@mail2.it.kth.se>
Message-ID: <36A2804D.5ED681C7@seanet.com>

Magnus Danielson wrote:
 
> Hmm, this would surely make a neat sub-base. Set it up with a 6 Hz
> sinewave, sit down on it and save yourself a ride on the ammusement
> park. As you hit the self-resonance you would basically go accutely
> very sick and damn yourself for comming up with this idea. It could
> also be a very cruel prank on a colleague, but I advice against such
> things.

Speaking of which, does anyone on this list know anything about the
subsonic death ray that France supposedly developed?  This is the sort
of weird rumor that tends to be circulated among insane musician
circles, so I figured someone on this list might know about it. :) It
might actually have been a real item; it supposedly generated a highly
directional beam of sound at an extremely high amplitude, around 7 Hz -
the "resonant frequency of the body," so as to turn your innards to
jello.  If such a device was actually developed, my guess would be that
it worked by using ultrasonic sound, and relying on the beat frequency
between two sound sources.  Example: use two ultra-powerful tweeter
horns, one at 100,000 Hz, one at 100,007 Hz.  

Anyone know anything about this?  If it was brought up in William S.
Burroughs' interview of Jimmy Page, it HAS to be true. :)

Sean Costello

P.S.  For a slightly more useful application along the same lines, see
the description of the "Audio Spotlight" at
http://sound.media.mit.edu/~pompei/spotlight/.

P.P.S.  I think that more emails should have the phrase "Death Ray" in
the title.



From irish at eskimo.com  Mon Jan 18 02:40:13 1999
From: irish at eskimo.com (Irish)
Date: Sun, 17 Jan 1999 17:40:13 -0800
Subject: Common supply
Message-ID: <9901171744290N.06937@Pandemonium>

Like everyone else I'm sure, I am amassing this collection of warts on my
wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just wire
everything to it? (9V because almost everything I have is 9V)
Is this a Bad Idea? 

Thanks, 
Irish

BTW, I got my Midi Thru box done - worked first pass (almost; had a bunk chip
but not my fault). 



From stew at uq.net.au  Mon Jan 18 03:13:43 1999
From: stew at uq.net.au (Stewart Pye)
Date: Mon, 18 Jan 1999 13:13:43 +1100
Subject: PAIA Hex VCA circuit
In-Reply-To: <199901172230.QAA17493@medusa.nn.com>
Message-ID: <199901180319.NAA17099@uq.net.au>

Hi there,

Arrgghh, using the 4049 as voltage controlled resistors. I tried this last
year for a phaser. I kind of got it to work but had some problems. I'll
take a look at my notes and see if I can do it now. Do you have the 4049
data sheet???? This might help you.( it contains the internal schematic )
If you could post the hex VCA schematic that would be great.

Regards,

Stewart Pye


At 16:30 17/01/99 -0600, Mark Smart wrote:
>Hi everyone.
>
>After forgetting about it for a year and a half, I have dived back into my
>GR-300 guitar synth hacking project. I have been messing with this circuit
>invented by PAIA which uses a 4049 CMOS chip to create six VCA's which mix
>into one output  (the output comes out the ground pin!). What I'm using
>this for is to mix together pulse and square waves derived from the
>GR-300's internal sawtooth waveform. My saw-to-pulse converter and octave
>dividers create three pulse waves which oscillate between 0 and +15 volts.
>
>This circuit mostly works execpt that there is noticeable leakage between
>channels which is especially bad at low volumes. I have three
>signals, the pulse wave, the /2 square wave, and the /4 square wave. When
>you turn on the control voltage for the /4 square wave, it comes on, but
>with a noticeable amount of the /2 and pulse signals leaking in. I would
>appreciate the advice of anyone who is familiar with this PAIA hex VCA
>circuit. I could also post a schematic at some point maybe. I tried
>lowering the 4.7 Meg resistors to 2.2 Meg, and this helped some, but did
>not eliminate the problem. My biggest problem in debugging the circuit is
>that I really don't understand how it works very well. The description
>which came with it does not go into that much detail. It does not specify a
>limit on CV or audio voltage ranges. The basic idea of the circuit is that
>the FET's in the CMOS inverter gate are used as voltage-controlled
>resistors, and somehow the audio inputs mix inside the chip and come out
>the ground pin.
>
>I would appreciate any advice. Also thanks to the people on the list who
>have helped me in the past in my sporadic forays into synth-building. 
>
>
>************************************************
>*     Mark Smart                               *
>*     Electronics Engineer                     *
>*     And Musician                             *
>*     smart at medusa.nn.com                      *
>************************************************
> 




From mirwin1 at istar.ca  Mon Jan 18 03:16:45 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Sun, 17 Jan 1999 21:16:45 -0500
Subject: Pre-distortion Diodes for Moog Ladder Filter
References: <36A27510.60D7B257@istar.ca> <199901172258.XAA21771@mail2.it.kth.se>
Message-ID: <36A2998C.CF596678@istar.ca>

I tried the following experiment. Fed a sine wave into an SSM2045
lowpass VCF and fed part of the output  back into the control voltage
input with a potentiometer, with the cutoff set to around 2 KHz. With
increasing audio-C.V. feedback, the sine is joined by a strong 3rd (
2nd?) harmonic and then becomes distinctly buzzy-sounding. The
distortion is less pronounced as the cutoff freq is increased.  It
sounds a bit like the Moog distortion ( but a real A/B test will have to
wait... )




From synth1 at airmail.net  Mon Jan 18 03:21:30 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 17 Jan 1999 20:21:30 -0600
Subject: Soldering
Message-ID: <001101be4289$4315af80$fcdbfea9@p400>

>From Ivan Schwartz:



>FYI - 
>
>There is a Weller guide to soldering you might include as a link from 
>your website for beginners:
>
>http://www.coopertools.com/pdffiles/55578.pdf
>
>Ivan
>




From vco at mindspring.com  Mon Jan 18 04:04:07 1999
From: vco at mindspring.com (tomg)
Date: Sun, 17 Jan 1999 22:04:07 -0500
Subject: vcf9a Surge Type SVF
Message-ID: <199901180309.WAA19612@smtp3.mindspring.com>

The VCF-9A is based on a Surge "VC Filter". I'm not sure which one. I
assume it is an older design as it used a LM3900 as an exp-converter. It is
a two pole state variable design with hi-pass, low-pass and band-pass
outputs. Sounds very "Electronic" for some reason. It's not that different
form the OBX type that has a pretty common low-pass sound.  Anyway I Iike
it.

My first html/graphics produced on a pc w/eztraks&word....not too bad..
seems to retain the flavor....pc mail now too....it's sad in a way...:-(
OTOH  they are selling 233+A/V cyrix boards for $125 these days ...pretty
snappy pops into just about anything. Very nice upgrade board. I'm not sure
Novell runs on it thought.

http://www.mindspring.com/~vco/misc/vcf9a.html

BTW I was on Aminet the other night and someone ( I would look but  this is
the wrong computer) wrote a prgm. That allows you to stuff the ram with
samples assigned a midi chnl/range w/pb and stereo pan. Sort of a poor-mans
sampler. Amiga samples have a very raw cool sound to them. It might be time
to pull that old A500 out of the closet. Might be time to find a used
one... they should be cheep these days but I don't recall seeing many
arround. I'll let you know if it works.

-tg
---------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
----------------------------------------------------------------------------











From aschrock at cs.brandeis.edu  Mon Jan 18 04:09:56 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sun, 17 Jan 1999 22:09:56 -0500 (EST)
Subject: SubSonic frequency talk...
Message-ID: <Pine.HPP.3.95.990117220901.20797A-100000@bay.cs.brandeis.edu>

This is from another list I'm on, kinda related to the discussion at hand.
All errors aren't mine, I didn't write this, so don't blame me. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|

---------- Forwarded message ----------
Date: Mon, 11 Jan 1999 15:34:47 -0500
From: Jeremy Warner <jwarner at MIT.EDU>
To: Sasha Costanza-Chock <schock at fas.harvard.edu>, underground at MIT.EDU
Subject: Re: [604] SOUND:just in case you didn't read this coz it  didn't have a subject 

At 03:24 PM 1/11/99 -0500, you wrote:
>the US military has since then developed an array of weapons that utilize
>the same principle. they like it because it is directional - as you point
>out, jeremy.  I'm sure you're wrong about the potential intensity of this
>kind of directional sound, though - in 1993 russian researchers announced
>the development of a 'sonic cannon' that works this way and is capable of
>penetrating tank armor.

Well the intensity is theoretically only limited by the mechanical
abilities of the transducer.  What you have to remember, though, is that
the amount of power to produce an appreciably large ultrasonic wave is
extremely high, mostly due to the atmosphere's nasty habit of soaking up
high frequencies.  This effect also occurs at audible frequencies, and is a
function of temperature and humidity.  In any venue of over 600ft, the high
frequencies need to be boosted to compensate for atmospheric loss.  But the
problem becomes much worse at ultrasonic frequencies.  You can look up the
tables in the CRC handbook.

Jeremy
----------------------
Niteshade Sound System
362 Memorial Dr. 
Cambridge, MA  02139
(617)225-7258





From WeAreAs1 at aol.com  Mon Jan 18 04:22:17 1999
From: WeAreAs1 at aol.com (WeAreAs1 at aol.com)
Date: Sun, 17 Jan 1999 22:22:17 EST
Subject: hs 60 vcf/gate in mod questions
Message-ID: <730ad0c6.36a2a8e9@aol.com>


In a message dated 1/17/99 10:01:01 AM, you wrote:

<<i emagine if i wanted to controll my juno hs60 with vcf and gate in
modifications i would have to put jack inputs on the front pannle routed to
what ><>?? the 80017A vfc/vca chip's<>??? where would i put the gate
input>>

The HS60/Juno 106 has software-generated envelopes.  As such, it has no
internal "gate" signal (except within its software).  You could trigger the
unit with an external gate in this manner:

1.  Disconnect the output of one the DCO's to its corresponding filter (I
suggest using voice #1)
2.  Connect your external signal to the input of that VCF
3.  Put the Juno in whichever Poly mode allows it to retrigger the same voice
repeatedly without voice-cycling (this is the Poly mode designed to be used
with portamento)
4.  Wire a 4066 analog switch across the keyboard key of your choice (I
suggest Middle C or the lowest C on the keyboard)
5.  Use your external gate to open and close the 4066

When you first press the Poly mode switch, the Juno's voise allocation will
reset to voice #1, and will stay there as long as you don't hit any keys on
the keyboard.  If it loses its place, simply hit the Poly mode switch again.

Wiring up the 4066 and audio input stuff may or may not be trivial, depending
upon your current electronic skill level.

Michael Bacich 



From vco at mindspring.com  Mon Jan 18 04:54:08 1999
From: vco at mindspring.com (tomg)
Date: Sun, 17 Jan 1999 22:54:08 -0500
Subject: CadCam
Message-ID: <199901180400.XAA21872@camel7.mindspring.com>

I ran across this win95 gerber viewer that works on eztrax files. It's free
as long as all you want to do is look, does lot's if you willing to pay.
It's great for checking your boards. I found other viewers that didn't
always work.

http://www.rsi-inc.com

-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------



From vco at mindspring.com  Mon Jan 18 04:56:31 1999
From: vco at mindspring.com (tomg)
Date: Sun, 17 Jan 1999 22:56:31 -0500
Subject: Cadcam 2
Message-ID: <199901180401.XAA15161@camel7.mindspring.com>

ohh they email the password to you if you give your address.

ccshare ftp://ftp.rsi-inc.com/pub/demo/win/ccshare.exe

-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------



From djblue at asu.edu  Mon Jan 18 05:11:55 1999
From: djblue at asu.edu (Reverend bluE)
Date: Sun, 17 Jan 1999 21:11:55 -0700 (MST)
Subject: another instrument question
Message-ID: <Pine.GSO.3.96.990117211041.18236B-100000@general1.asu.edu>


my last one... (maybe)  


okay, the same issue of Future Music here, (december I think)

page 69 shows a weird guitar-esque keyboard that Add N To X uses.
anybody have any information on this bad boy?

-ben




From djblue at asu.edu  Mon Jan 18 05:15:38 1999
From: djblue at asu.edu (Reverend bluE)
Date: Sun, 17 Jan 1999 21:15:38 -0700 (MST)
Subject: question about transistors.
Message-ID: <Pine.GSO.3.96.990117211231.18236C-100000@general1.asu.edu>


I was trying to make the Maxx modular VCO1 and I hooked up one of the
transistors backwards, and applied power to it.  would this "blow" it?  or
anything else?  THe one hooked up wrong is one of the two that are right next
to each other by op-amp1.  I've hooked them up corrdctly, and the thing still
doesn't make any sounds (except for the radio stations that I can tune in with
it)...  I have two MAT-02's and I was wondering if I should throw one of these
in there in place of the two transistors.  

In any case, what are the pin-outs for the MAT-02??  
-ben




From newtek at internet-profits.com  Mon Jan 18 07:15:41 1999
From: newtek at internet-profits.com (newtek at internet-profits.com)
Date: Mon, 18 Jan 1999 07:15:41 +0100
Subject: AD: Pay Off Your Home Mortgage Within 2 to 5 Years
Message-ID: <E1027yO-0006vh-00@mgate.unisource.nl>

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From bvdwal at casema.net  Mon Jan 18 07:16:55 1999
From: bvdwal at casema.net (Bauke van der Wal)
Date: Mon, 18 Jan 1999 07:16:55 +0100
Subject: Subsonic Death Rays ...
Message-ID: <36A2D1D7.7A23@casema.net>

the album of the psychophysisist (b. lustmord, adi newton and a.
logowski) contains some words on this subject. if anybody is interested
i could type it in later (first my dayjob ;-) 

just let me now ...

greetings,
b.
-- 
"we are ugly, but we have the music" - l. cohen



From zzynt at swipnet.se  Mon Jan 18 08:04:41 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 17 Jan 1999 23:04:41 -0800
Subject: Oscillator idea come's unstuck
References: <199901171504.JAA22049@echo.flash.net>
Message-ID: <36A2DD09.60AA@swipnet.se>

Scott Gravenhorst wrote:
> 
> This looks like a triangle summed with a square wave.  Couldn't the
> triangle be derived by subtracting the oscillator's square output?  I
> would suspect that it should be in phase with this.
> 
> >>    /l      /l
> >>   / l     / l
> >>  /  l    /  l
> >> /   l   /   l
> >>     l   l
> >>     \   l
> >>      \  l
> >>       \ l
> >>        \l
> 
> -- Scott Gravenhorst
> -- RedWebMail by RedStarWare (srg)
> -- FatMan Site: www.teklab.com/~chordman
> -- Linux Rex, Linux Vobiscum

No i dont think soo, because the saw is twice the 
frequency of the square!

But another interesting thing is the clean and nice PWM
you gett when driving the saw thru the xor gate.

And another interesting thing is the "fixed" frequency
and the "second" phase pulse pointing of the xor gate
when you are sending the saw to both of the xor gate
input pins.

If yo do so then you get a short output pulse at pin 1 (i think)
at the frequency of the saw and as you warying the
PW (dc shift) of the saw there appers another short pulse
in the pulse train.This pulse moves from ether side of
the stable pulse trains outher limits.

(Ooh dear, what this was difficult for me to explain!!!)

I have no idea on what one would use this for!!:)

Plashe plonting plotter plablpthpthpfftp!!!

BJ



From jorgen.bergfors at idg.se  Mon Jan 18 08:18:07 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 18 Jan 1999 8:18:07 +0100
Subject: 2N4391/92
Message-ID: <TFSHPRCU@idg.se>

You can buy 2N4391 at www.elfa.se. Catalog number is 71-625-48 and the price is SEK 26.00 Rather expensive, but they seem to be NOS. I bought some a month ago and they were manufactured in 1984.

/Jorgen




MIME:pfperry at melbpc.org.au on 99-01-16 00:11:52
To:  synth-diy at mailhost.bpa.nl @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: 2N4391/92 

At 09:16 PM 15/01/99 +0200,biotek Janne Heikkarainen wrote:
>it seems that i can't locate this transistor anywhere...are there any good >replacements for it?
>
2N4391 equiv 2N4865  BSF74 

2N4392 equiv 2N5434

paul perry melb aust










From martin.czech at intermetall.de  Mon Jan 18 08:21:24 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 18 Jan 1999 08:21:24 +0100 (MET)
Subject: gnuplot !
Message-ID: <199901180721.IAA21718@window.intermetall.de>

Sometimes it is quite nice to see, if some calculation is
correct, or how a function graph looks like etc,
before detecting a fault AFTER soldering.

Therefore you need some kind of plot tool.


I have now found gnuplot for DOS:

e.g. (and other paces)

http://ftp.gts.cz/FTP/pub/gnu/gnuplot/old/

"
DOS34.zip has 386 and 486 precompiled binaries for gnuplot 3.4 (not
3.5). This is explained further in DOS34.txt. 
"

Yes it is DOS, but it is a command line tool anyway.
Needs some preparation of the Win95-DOS window properties,
default options seem not to work.

To avoid ugly non WIN output, you can 

set output "filename"
set term pbm color


and then use Lview from

http://kronos.ijs.si/~jure/gutils/gutil_sv.html#Windows95D

to convert pgm to everything.


All shareware/public domain!

m.c.




From martin.czech at intermetall.de  Mon Jan 18 09:02:08 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 18 Jan 1999 09:02:08 +0100 (MET)
Subject: sneaking in a CMOS VCO
Message-ID: <199901180802.JAA21982@window.intermetall.de>


> >
> >Well, how about "sneeking" in a CMOS VCO onto the wafer film then?
> >
> Wow, this is what we need, 'Easter Eggs' in chips!
> (to access the on-chip vocoder, hold all pins high for 30MS and toggle 
> pin 5 three times)
> 
> paul perry, destroying productivity on fab lines world-wide
> 
> 
No chance, you are allways short in test observability, thus
this mode is used for testing purposes since long ;->.

m.c.




From zzynt at swipnet.se  Mon Jan 18 09:07:29 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 18 Jan 1999 00:07:29 -0800
Subject: Pre-distortion Diodes for Moog Ladder Filter
References: <36A23EDA.B2476444@istar.ca> <199901172028.VAA20982@mail2.it.kth.se>
Message-ID: <36A2EBC1.7D51@swipnet.se>

Magnus Danielson wrote:
> 
> >>>>> "MBI" == Michael B Irwin <mirwin1 at istar.ca> writes:
> 
>  MBI> Hi,
>  MBI> Has anyone thought about or tried adding linearizing diodes to the audio
>  MBI> input of a Moog VCF ? This would be similar to the predistortion circuit
>  MBI> used in the CA3280 and LM13600. Presumably this could be used to change
>  MBI> the filter performance from the traditional warm-sounding gentle
>  MBI> distortion ( with plenty of background hiss ) to a cleaner, higher
>  MBI> signal-noise ratio mode ( more like other VCF's). It would be neat to be
>  MBI> able to switch between these two modes.
> 
> Well, I have considered these diodes, only to figure out that they
> would probably not really help all that much. They would help to
> compensate for the tanh distorsion of the input transistor pair.

Agree, I'v tested in reality and it does not gain much, its just a
hassle
to del with it, try instead to balance the ladder instead to minimise
the noise!
 
> However, this is not the same as compensating the distorsion of the
> transistors higher up in the ladder. In Dr. Moog's filterpatent it is
> clearly stated that the signal level is kept so that the signal
> current is much lower than the modulation current in order to keep
> distorsion down. What happends is that the signal will not only
> experience direct distorsion, but also modulate the poles in the
> filter. This is a non-linear filter responce, but it may be nice to
> the ear.

Well nothing new in that, the Moog filter is highly non linear allready
and distorting the filter has allready been done long time ago
whit the results of a "not so nice to the ear" responce" because of 
all the added noise that does to the cirquit!
What seems to bee an gained parameter in theory is in reality drovned in
noise!!

Thats the problem with the Moog filter, "its noisy" as hell and 
as son as levels are shifted you add noise.

Take the MS20 VCA, if that one is feed with a to strong signal it 
either rectifying the signals on various ways or it makes a tri wave
into a sine wave, for those who need a voltage controlled tri to sine
shaper! 


BJ



From zzynt at swipnet.se  Mon Jan 18 09:16:51 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 18 Jan 1999 00:16:51 -0800
Subject: Oscillator idea come's unstuck
References: <36A2DD09.60AA@swipnet.se> <199901172315.AAA22005@mail2.it.kth.se>
Message-ID: <36A2EDF3.7420@swipnet.se>

plablpthpthpfftp plablpthpthpfftp plablpthpthpfftp....Phhhhasaaaaseee...

Phaaase, phase, in phase again, ho hum! beeep!

> We better make a square of the right frequency then. I think we have
> found the source for BJ's and mine 90/180 degree disagreement. We are
> just thinking in two diffrent frequencies. I knew there where
> something banal about it.

Well thats solve our problem i think (after rebooted BJ)!

BJ.



From jorgen.bergfors at idg.se  Mon Jan 18 09:43:37 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 18 Jan 1999 9:43:37 +0100
Subject: Common supply
Message-ID: <TFSHSOZU@idg.se>

I connected a Novation Bass Station and a Casio DA-R100 to the same home-built 9 V DC supply. The result was that when the DAT-recorder was on, I got some slight noise on the Bass Station output. I had to add a filter, consisting of inductors and capacitors, between the units to remove the noise. Anyway, this solved the problem and now I use this hookup. I didn't even buy the wallwart for the Bass Station (it wasn't included in the price).

/Jorgen





MIME:irish at eskimo.com on 99-01-18 03:27:10
To:  synth-diy at mailhost.bpa.nl @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Common supply 

Like everyone else I'm sure, I am amassing this collection of warts on my
wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just wire
everything to it? (9V because almost everything I have is 9V)
Is this a Bad Idea? 

Thanks, Irish

BTW, I got my Midi Thru box done - worked first pass (almost; had a bunk chip
but not my fault). 













From jaheikka at cc.spt.fi  Mon Jan 18 10:10:57 1999
From: jaheikka at cc.spt.fi (Janne Heikkarainen)
Date: Mon, 18 Jan 1999 11:10:57 +0200 (EET)
Subject: 2N4391/92
In-Reply-To: <TFSHPRCU@idg.se>
Message-ID: <Pine.SOL.3.91.990118110510.6607B-100000@jazz>

On Mon, 18 Jan 1999 jorgen.bergfors at idg.se wrote:

> You can buy 2N4391 at www.elfa.se. Catalog number is 71-625-48 and the price is SEK 26.00 Rather expensive, but they seem to be NOS. I bought some a month ago and they were manufactured in 1984.
> 
That price is per piece? Whoa...

> >it seems that i can't locate this transistor anywhere...are there any good >replacements for it?
> >
> 2N4391 equiv 2N4865  BSF74 
> 
> 2N4392 equiv 2N5434
> 
> paul perry melb aust
> 
hmm i need this one to the Maxx vco4a...Is the 2N4393 a good replacement 
for it? 

.biotek




From Colin.Fraser at scottishpower.plc.uk  Mon Jan 18 11:04:15 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 18 Jan 1999 10:04:15 -0000
Subject: Common supply
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2BF@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Irish [mailto:irish at eskimo.com]
> Sent: 18 January 1999 01:40
> To: DIY
> Subject: Common supply
> 
> 
> Like everyone else I'm sure, I am amassing this collection of 
> warts on my
> wall/floor/etc. Any reason I can't get/make a 9V 3A supply 
> and just wire
> everything to it? (9V because almost everything I have is 9V)
> Is this a Bad Idea? 

I tried building a 9v supply to power both my 303 and 606, and ran into
problems.
For some reason, I couldn't connect both units shield connections on their
audio outputs together or I got a loud pumping noise from both units - they
were OK if either their outputs or power supplies were isolated.
In the end, I built a PSU with one transformer, but separate recitifers,
regultators and power outputs for each unit.


Colin f



From Juergen.Haible at nbgm.siemens.de  Mon Jan 18 11:21:58 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 18 Jan 1999 11:21:58 +0100
Subject: AW: Subsonic Death Rays (was Re: day job)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820120C329@nbgm336a.nbgm.siemens.de>

"They told us what they wanted was a sound that could 
kill someone"
(Kate Bush, Experiment IV)
Just fiction, but an excellent song. (And a nice video.)

And "Dune" comes to mind - fiction, too, but an excellent book.

(Sorry for being even more off topic)

JH.




From gary at nrtg.com  Mon Jan 18 12:36:51 1999
From: gary at nrtg.com (Gary Morgan)
Date: Mon, 18 Jan 1999 11:36:51 -0000
Subject: Construction notes for ETI MIDI/CV interface
Message-ID: <c=GB%a=_%p=NRTT%l=MARIUS_N-990118113651Z-5@pc130.nrtg.com>

I have the parts for an old ETI MIDI/CV interface. This was given to me
by
a friend who partially constructed the kit. I don't have the
construction notes,
however, which makes finishing it a little tricky:-) Therefore, I would
be
grateful if anyone could point to a place where the construction notes
might
be available.

Many thanks in advance

gary morgan




From Juergen.Haible at nbgm.siemens.de  Mon Jan 18 13:21:37 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 18 Jan 1999 13:21:37 +0100
Subject: AW: PAIA Hex VCA circuit
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820120C521@nbgm336a.nbgm.siemens.de>

I haven't seen the schemos (I'd like to see them, though!),
but here is a wild guess how it might work:
Use the GND connection as common output (you already 
said that), use the inverter inputs as CV inputs, and the inverter
outputs (!) as signal inputs. That way you would have a single
n-channel MOSFET (as VC resistor) between your signal
inputs (i.e. inverter outputs) and the common output (i.e. 
inverter GND). No idea *if* this works, but given the fact that
you can use the cip as hex vca, this might be the way to do it.
You'd best connect the "GND" output to a virtual GND (opamp)
summing node to avoid crossmodualtion between the individual 
signals.

Just a wild guess,

JH.

> ----------
> Von: 	Mark Smart[SMTP:smart at nn.com]
> Gesendet: 	Sonntag, 17. Januar 1999 23:30
> An: 	synth-diy at mailhost.bpa.nl
> Betreff: 	PAIA Hex VCA circuit
> 
> Hi everyone.
> 
> After forgetting about it for a year and a half, I have dived back into my
> GR-300 guitar synth hacking project. I have been messing with this circuit
> invented by PAIA which uses a 4049 CMOS chip to create six VCA's which mix
> into one output  (the output comes out the ground pin!). What I'm using
> this for is to mix together pulse and square waves derived from the
> GR-300's internal sawtooth waveform. My saw-to-pulse converter and octave
> dividers create three pulse waves which oscillate between 0 and +15 volts.
> 
> This circuit mostly works execpt that there is noticeable leakage between
> channels which is especially bad at low volumes. I have three
> signals, the pulse wave, the /2 square wave, and the /4 square wave. When
> you turn on the control voltage for the /4 square wave, it comes on, but
> with a noticeable amount of the /2 and pulse signals leaking in. I would
> appreciate the advice of anyone who is familiar with this PAIA hex VCA
> circuit. I could also post a schematic at some point maybe. I tried
> lowering the 4.7 Meg resistors to 2.2 Meg, and this helped some, but did
> not eliminate the problem. My biggest problem in debugging the circuit is
> that I really don't understand how it works very well. The description
> which came with it does not go into that much detail. It does not specify
> a
> limit on CV or audio voltage ranges. The basic idea of the circuit is that
> the FET's in the CMOS inverter gate are used as voltage-controlled
> resistors, and somehow the audio inputs mix inside the chip and come out
> the ground pin.
> 
> I would appreciate any advice. Also thanks to the people on the list who
> have helped me in the past in my sporadic forays into synth-building. 
> 
> 
> ************************************************
> *     Mark Smart                               *
> *     Electronics Engineer                     *
> *     And Musician                             *
> *     smart at medusa.nn.com                      *
> ************************************************
> 



From Colin.Fraser at scottishpower.plc.uk  Mon Jan 18 15:19:54 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 18 Jan 1999 14:19:54 -0000
Subject: Oscillator idea come's unstuck
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2C1@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Rene Schmitz [mailto:uzs159 at uni-bonn.de]
> Sent: 17 January 1999 23:05
> To: Fraser, Colin J
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: Oscillator idea come's unstuck
> 
> I don't want to discourage anyone, but either its that the 
> two switches are
> conducting simultaneously. (as J?rgen said)
> But I suspect another thing: I've read in Horowitz & Hill Chapter 3.12
> "Limitations of FET switches", that some (and they mention 
> the 4066) analog
> switches have the nasty property to short (!) the input to ground
> momentarily. 
> If that might happen, then the charge would leak to ground.
> I would try it with a 4016 which is different to 4066.

This could be it - I tried various different 4066s to see if I got different
results. With one device there was a noticable spike at the top of the
triangle wave - but the wave continued normally after this. This spike could
be the result of the momentary short mentioned.

> Apart from this it might could be that the R(on) of the 
> switch varies with
> the voltage on its inputs. The 4066 is better in this regard 
> than the 4016. 

IIRC the 4016 has the same pinout as the 4066, so I'll get hold of one and
try it in the circuit.
Maybe the best bet is to use discrete FETs.


Colin f



From thelab at sprint.ca  Mon Jan 18 15:55:19 1999
From: thelab at sprint.ca (Philip)
Date: Mon, 18 Jan 1999 11:55:19 -0300
Subject: Sick JP-8..help needed
References: <199901180721.IAA21718@window.intermetall.de>
Message-ID: <36A34B57.564A@sprint.ca>

hi all,

A freind sent me this. I am not familiar with the JP-8. Any suggestions?
All are welcome.
Philip

> BTW, I'm not
> sure how familiar you are with the Jupiter 8, but I figured that you might
> know something about it since you plan on doing some Jupiter 6 mods. Somebody
> I know is having some problems with his JP8. He just got it back from a tech
> who had it for 6 months or a year or something and he still couldn't fix the
> problem. It is as follows:
> 
> VCO 1 on Voice A is drifting eractically. Due to the analog nature, all the
> VCOs drift a little, but there is a discinct problem with this particular VCO.
> The best way to describe it is, let's say I tune VCO 1 and 2 to unison so
> there is no beating. Well VCO 1 will stay stable for a few seconds, then
> suddenly drift so you will hear beating between the oscillators(major beating)
> and then will come back in line every so often. There is no pattern or logic
> to this behavior. The tech I took it to said he thinks there is some kind of
> noise being introduced into the VCO 1 circuit causing this unstability, but he
> does not know how to get rid of it. He replaced all of the following chips
> surrounding this circuit:
> 
> CA3046
> R9A
> R12
> R10
> IC1A,3A
> TR1A
> TLO81 chip
> 4558 chip
> 25A1015
> 
> Even after all this the problem still exists. Anything that can get this
> keyboard going again would be awesome. I really miss playing it.




-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From tpaddock at seanet.com  Mon Jan 18 15:58:13 1999
From: tpaddock at seanet.com (Toby Paddock)
Date: Mon, 18 Jan 1999 06:58:13 -0800
Subject: Subsonic Death Rays (was Re: day job)
Message-ID: <01BE42B0.1CC4F620@d15.dialup.seanet.com>

Reminds me of the quote:

"Undoubtedly, the most momentous piece of 
progress of 1969 occurred in Dijon, France 
on August 14 when Neil Rappaport of Festonna, 
NJ, lost forever the blueprints for a machine 
he had just invented which would have made it 
possible to create a louder noise then had ever 
been heard before." 
-- Russell Baker, New York Times, February 14, 1970

The loudest lowest *tone* I've been around was
Survival Research Lab's pulsejet.  I'm guessing
10-15 Hz?

In a lame attempt to make this on-topic I'll mention
when I did a vib test on a Velodyne subwoofer.  It has 
an accelerometer on the cone in a servo loop.  It was
powered, but no audio signal.  When I shook it at low
freq sine, the cabinet moved, but the cone tried to 
stay in on place.  

Hoping this finds you,
Toby Paddock
- -- -  - -- -  - -- -  - -- -  - -- -
http://www.seanet.com/~tpaddock
Pronteon Approved, 
not servo controlled





From ijfritz at earthlink.net  Mon Jan 18 16:21:27 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Mon, 18 Jan 1999 08:21:27 -0700
Subject: 2N4391/92
References: <Pine.SOL.3.91.990118110510.6607B-100000@jazz>
Message-ID: <36A35177.96BA77AF@earthlink.net>


Janne Heikkarainen wrote:
> 
> On Mon, 18 Jan 1999 jorgen.bergfors at idg.se wrote:
> 
> > You can buy 2N4391 at www.elfa.se. Catalog number is 71-625-48 and the price is SEK 26.00 Rather expensive, but they seem to be NOS. I bought some a month ago and they were manufactured in 1984.
> >
> That price is per piece? Whoa...


$1.28 at Mouser. Seems to still be in production.


> 
> > >it seems that i can't locate this transistor anywhere...are there any good >replacements for it?
> > >
> > 2N4391 equiv 2N4865  BSF74
> >
> > 2N4392 equiv 2N5434
> >
> > paul perry melb aust
> >
> hmm i need this one to the Maxx vco4a...Is the 2N4393 a good replacement
> for it?

NO! 2N4393 = 5mA max current. 2N4391 = 50mA. 

> 
> .biotek



From IXQY at aol.com  Mon Jan 18 16:26:10 1999
From: IXQY at aol.com (IXQY at aol.com)
Date: Mon, 18 Jan 1999 10:26:10 EST
Subject: Subsonic Death Rays (was Re: day job)
Message-ID: <9fe2dee7.36a35292@aol.com>

In a message dated 99-01-18 10:12:25 EST, tpaddock at seanet.com writes:

<< In a lame attempt to make this on-topic I'll mention
 when I did a vib test on a Velodyne subwoofer.  It has 
 an accelerometer on the cone in a servo loop.  It was
 powered, but no audio signal.  When I shook it at low
 freq sine, the cabinet moved, but the cone tried to 
 stay in on place.  
  >>

 A really weird thing with those Velodyne subs with the accelerometer - if you
tap your finger on the cone (no audio input, but with power on), the servo
loop tries to compensate for this "uncalled for" cone movement.... It Rings!
 Great sounding sub though.

  Andrew Sanchez



From Chris.List at sc.siemens.com  Mon Jan 18 17:16:43 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 18 Jan 1999 11:16:43 -0500
Subject: Subsonic Death Rays - KLF?
Message-ID: <81A062BC5305D111A9D700805F06596801836C76@maildepo.sc.siemens.com>

This sounds rather like one of the notorious KLF hoaxes pulled by
getting a news paper article printed about a huge sonic death machine or
something at their compound in the English country side. I read the
story a while ago, and am not too clear on the facts. You can find the
story somewhere around on the net.

- CList

> -----Original Message-----
> From:	Sean Costello [SMTP:costello at seanet.com]
> Sent:	Sunday, January 17, 1999 7:29 PM
> To:	Magnus Danielson
> Cc:	tpaddock at seanet.com; synth-diy at mailhost.bpa.nl
> Subject:	Subsonic Death Rays (was Re: day job)
> 
> Speaking of which, does anyone on this list know anything about the
> subsonic death ray that France supposedly developed?  This is the sort
> of weird rumor that tends to be circulated among insane musician
> circles, so I figured someone on this list might know about it. :) It
> might actually have been a real item; it supposedly generated a highly
> directional beam of sound at an extremely high amplitude, around 7 Hz
> -
> the "resonant frequency of the body," so as to turn your innards to
> jello.  If such a device was actually developed, my guess would be
> that
> it worked by using ultrasonic sound, and relying on the beat frequency
> between two sound sources.  Example: use two ultra-powerful tweeter
> horns, one at 100,000 Hz, one at 100,007 Hz.  
> 
> Sean Costello
> 
> 



From wils0450 at itlabs.umn.edu  Mon Jan 18 17:51:50 1999
From: wils0450 at itlabs.umn.edu (M wIlson)
Date: Mon, 18 Jan 1999 10:51:50 -0600 (CST)
Subject: Subsonic Death Rays (is now way-OT)
In-Reply-To: <9fe2dee7.36a35292@aol.com>
Message-ID: <Pine.GSO.4.05.9901181045580.26670-100000@walrus.itlabs.umn.edu>

I happen too know first hand that "Rollers" (people dosed on the
drug ecstacy) absolutely can not take a good shot of bass to the belly.I have 
used low-low frequency sine waves for a bassline or two on on more than a 
few occasions. Makes rollers sick to their stomachs. I have never seen so
many people participate in synchronized vomiting in my life. Gross, but
fun! (most of the flies near my home are missing wings :)
Gawd, couldn't get much more off topic than that.   


			 The Family Werks presents...
                          Performing live at "Love"
		Valentine's day weekend in Minneapolis, MN USA
             ****Sonic Boom of Love featuring Clarissa Fragile*****
	       (also Boo WIlliams and some other big-name chumps)





From THEKn0TiS at aol.com  Mon Jan 18 17:53:53 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Mon, 18 Jan 1999 11:53:53 EST
Subject: hs 60 vcf/gate in mod questions
Message-ID: <91b52d08.36a36721@aol.com>

<<>?? the 80017A vfc/vca chip's<>??? where would i put the gate
input>>

                 Michael Bacich wrote

<The HS60/Juno 106 has software-generated envelopes.  As such, it has no
<internal "gate" signal (except within its software).  You could trigger the
<unit with an external gate in this manner:

<1.  Disconnect the output of one the DCO's to its corresponding filter (I
suggest using voice #1)
<2.  Connect your external signal to the input of that VCF
<3.  Put the Juno in whichever Poly mode allows it to retrigger the same voice
<repeatedly without voice-cycling (this is the Poly mode designed to be used
<with portamento)
<4.  Wire a 4066 analog switch across the keyboard key of your choice (I
<suggest Middle C or the lowest C on the keyboard)
<5.  Use your external gate to open and close the 4066

<When you first press the Poly mode switch, the Juno's voise allocation will
<reset to voice #1, and will stay there as long as you don't hit any keys on
<the keyboard.  If it loses its place, simply hit the Poly mode switch again.

<Wiring up the 4066 and audio input stuff may or may not be trivial, depending
<upon your current electronic skill level.

<Michael Bacich 

thankee very much should be easy enuff,... i was kinda hoping it could be
modified to act like my juno 60 with the vcf input and the arpegiater clock in
but the hs60 has no arpeg.. :) this seem's like it will do the trick 

thanxs for the input

shawn



From THEKn0TiS at aol.com  Mon Jan 18 18:27:12 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Mon, 18 Jan 1999 12:27:12 EST
Subject: soundcard midi/joystick port adapter question
Message-ID: <f0686bf.36a36ef0@aol.com>

i have an awe 64 with the standerd midi / joystick port,...

where do i get the adapter that lets me plug it into midi devices like a tg33
or a hs60 for instance or plug midi devices into it,... i have ytried music
stores and computer stores no one seems to know where i would get such a
creature i know what it looks like it has one end that plugs into the game
port and one end that lets a standard midi cable plug into it (i immagine) 

pweeeze help
thanx
shawn



From Chris.List at sc.siemens.com  Mon Jan 18 18:52:01 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 18 Jan 1999 12:52:01 -0500
Subject: soundcard midi/joystick port adapter question
Message-ID: <81A062BC5305D111A9D700805F06596801836C7B@maildepo.sc.siemens.com>

These are available all over, any of the larger music stores should have
them (e.g. I've bought them off the shelf at Sam Ash stores in both NY
and NJ). 
Try giving Sweetwater a call ( http://www.sweetwater.com ) - I'm sure
they can hook you up with one for a good price, and they throw candies
into the box with the stuff they ship :)

- CList

> -----Original Message-----
> From:	THEKn0TiS at aol.com [SMTP:THEKn0TiS at aol.com]
> Sent:	Monday, January 18, 1999 12:27 PM
> To:	digitalhell at resrocket.com; analogue at hyperreal.org;
> synth-diy at mailhost.bpa.nl
> Subject:	soundcard midi/joystick port adapter question
> 
> i have an awe 64 with the standerd midi / joystick port,...
> 
> where do i get the adapter that lets me plug it into midi devices like
> a tg33
> or a hs60 for instance or plug midi devices into it,... i have ytried
> music
> stores and computer stores no one seems to know where i would get such
> a
> creature i know what it looks like it has one end that plugs into the
> game
> port and one end that lets a standard midi cable plug into it (i
> immagine) 
> 
> pweeeze help
> thanx
> shawn



From johns at oei.com  Mon Jan 18 19:57:59 1999
From: johns at oei.com (John Speth)
Date: Mon, 18 Jan 1999 10:57:59 -0800
Subject: 19 in rack panel sources?
Message-ID: <000501be4314$77a10200$2c15d7d0@johns.oei.com>

Does anybody know of a source of blank 19" w x 17.5" h rack panels painted black in the USA?  Mouser has what I need in white and grey but no black.  (Too lazy to paint)

John Speth
Object Engineering, Inc
mailto:johns at oei.com
 





From s9610068 at chelt.ac.uk  Mon Jan 18 20:22:49 1999
From: s9610068 at chelt.ac.uk (James Dunn)
Date: Mon, 18 Jan 1999 19:22:49 +0000
Subject: Thomas part numbers
Message-ID: <36A38A09.15C0@chelt.ac.uk>

Hi all,

	Could anyone enlighten me on some Thomas chips from the Troubadour
Organ? They use their own part numbers:

13-5045-6; LSI 101 Keyer, 
13-5027-6; LSI Rhythm counter, and 
13-5032-6; LSI Features.

I have tried numerous searches, someone mentioned on this list (I
think), that the parts were originally SSM parts with the Thomas number
stamped on top. Is this true? Are Thomas still going, I can't seem to
find them anywhere. Any information appreciated.
Thanks,

James.



From magnus at analogue.org  Mon Jan 18 20:38:18 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 18 Jan 1999 20:38:18 +0100
Subject: Pre-distortion Diodes for Moog Ladder Filter
In-Reply-To: Your message of "Mon, 18 Jan 1999 00:07:29 -0800"
References: <36A2EBC1.7D51@swipnet.se>
Message-ID: <199901181938.UAA14602@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 >> Well, I have considered these diodes, only to figure out that they
 >> would probably not really help all that much. They would help to
 >> compensate for the tanh distorsion of the input transistor pair.

 B> Agree, I'v tested in reality and it does not gain much, its just a
 B> hassle
 B> to del with it, try instead to balance the ladder instead to minimise
 B> the noise!

Makes sence.
 
 >> However, this is not the same as compensating the distorsion of the
 >> transistors higher up in the ladder. In Dr. Moog's filterpatent it is
 >> clearly stated that the signal level is kept so that the signal
 >> current is much lower than the modulation current in order to keep
 >> distorsion down. What happends is that the signal will not only
 >> experience direct distorsion, but also modulate the poles in the
 >> filter. This is a non-linear filter responce, but it may be nice to
 >> the ear.

 B> Well nothing new in that, the Moog filter is highly non linear allready
 B> and distorting the filter has allready been done long time ago
 B> whit the results of a "not so nice to the ear" responce" because of 
 B> all the added noise that does to the cirquit!
 B> What seems to bee an gained parameter in theory is in reality drovned in
 B> noise!!

Certainly, there are some "nice" properties in the Moog ladder
especially with late 60thies standards, but several waves of competent
OTAs, VCAs etc. has flooded the market since.

 B> Thats the problem with the Moog filter, "its noisy" as hell and 
 B> as son as levels are shifted you add noise.

Rigth. Say that you dimension the signal to peak at 1 % of the
modulation current, then your signal is -40 dB of the modulation
current. Also, think of the varying noise in the curcuit as we
modulate things. What a mess basically.

 B> Take the MS20 VCA, if that one is feed with a to strong signal it 
 B> either rectifying the signals on various ways or it makes a tri wave
 B> into a sine wave, for those who need a voltage controlled tri to sine
 B> shaper! 

Oups. But then, I like my MS-20 as it is ;)

Cheers,
Magnus



From magnus at analogue.org  Mon Jan 18 20:53:04 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 18 Jan 1999 20:53:04 +0100
Subject: Subsonic Death Rays (was Re: day job)
In-Reply-To: Your message of "Sun, 17 Jan 1999 16:29:01 -0800"
References: <36A2804D.5ED681C7@seanet.com>
Message-ID: <199901181953.UAA14694@mail2.it.kth.se>

>>>>> "SC" == Sean Costello <costello at seanet.com> writes:

 SC> Magnus Danielson wrote:
 >> Hmm, this would surely make a neat sub-base. Set it up with a 6 Hz
 >> sinewave, sit down on it and save yourself a ride on the ammusement
 >> park. As you hit the self-resonance you would basically go accutely
 >> very sick and damn yourself for comming up with this idea. It could
 >> also be a very cruel prank on a colleague, but I advice against such
 >> things.

 SC> Speaking of which, does anyone on this list know anything about the
 SC> subsonic death ray that France supposedly developed?  This is the sort
 SC> of weird rumor that tends to be circulated among insane musician
 SC> circles, so I figured someone on this list might know about it. :) It
 SC> might actually have been a real item; it supposedly generated a highly
 SC> directional beam of sound at an extremely high amplitude, around 7 Hz -
 SC> the "resonant frequency of the body," so as to turn your innards to
 SC> jello.  If such a device was actually developed, my guess would be that
 SC> it worked by using ultrasonic sound, and relying on the beat frequency
 SC> between two sound sources.  Example: use two ultra-powerful tweeter
 SC> horns, one at 100,000 Hz, one at 100,007 Hz.  

Argh. 7 Hz, I just *knew* it was either of them, so I picked
one. Besides, you would notice ;)

 SC> Anyone know anything about this?  If it was brought up in William S.
 SC> Burroughs' interview of Jimmy Page, it HAS to be true. :)

Well, this is by no means new.

Here in Sweden a new such device has been built, so that you may send
a directed subsonic boom onto a person in order to temporarilly
disable them from anything possibly dangerous. FOA showed of such a
device in the national TV channel news, and they thought it could be
usefull in peace keeping missions, especially to control civilans.

I have heard about an old British military device that where intended
to work in the battle field.

 SC> Sean Costello

 SC> P.S.  For a slightly more useful application along the same lines, see
 SC> the description of the "Audio Spotlight" at
 SC> http://sound.media.mit.edu/~pompei/spotlight/.

 SC> P.P.S.  I think that more emails should have the phrase "Death Ray" in
 SC> the title.

Certainly. Especially as we are all getting our Magocrapial Atomic
Energy modular (also known as the Power Plant synth) soon. This is of
course a fresh retake on the rumbling success of the Telharmonicum,
but in a new, larger, improved and more powerfull version. One famous
reference installation is the Ignalina one, where as the Tjernobyl one
did not quite deal with the late nigth excercises.

The University that I worked for used to have their own!

Cheers,
Magnus



From magnus at analogue.org  Mon Jan 18 21:12:13 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 18 Jan 1999 21:12:13 +0100
Subject: AW: PAIA Hex VCA circuit
In-Reply-To: Your message of "Mon, 18 Jan 1999 13:21:37 +0100"
References: <1BF5E20E0C4DD111BBAB00805FE2D5820120C521@nbgm336a.nbgm.siemens.de>
Message-ID: <199901182012.VAA14933@mail2.it.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 HJ> I haven't seen the schemos (I'd like to see them, though!),
 HJ> but here is a wild guess how it might work:
 HJ> Use the GND connection as common output (you already 
 HJ> said that), use the inverter inputs as CV inputs, and the inverter
 HJ> outputs (!) as signal inputs. That way you would have a single
 HJ> n-channel MOSFET (as VC resistor) between your signal
 HJ> inputs (i.e. inverter outputs) and the common output (i.e. 
 HJ> inverter GND). No idea *if* this works, but given the fact that
 HJ> you can use the cip as hex vca, this might be the way to do it.
 HJ> You'd best connect the "GND" output to a virtual GND (opamp)
 HJ> summing node to avoid crossmodualtion between the individual 
 HJ> signals.

This is exactly how I preceived it. I would feed the input with CV
through a 100 kohm resistor and also feed the signal into the input
through a 100 kohm resistor, this way would the N-channel MOSFET be
linearized. If you do not feed too hot signals on this, it will act in
the linear region of the FET curve, so it would actually work as well
as a single FET, but here you got 6 of them wired up for a fairly
small price. Important not is however that this only works well with
the unbuffered 4069, the buffered one is not as fun (to say the least).

It's wild, it's hilarious... got to try just for the sake of it ;)

Cheers,
Magnus



From chrisc at zetnet.co.uk  Mon Jan 18 23:51:31 1999
From: chrisc at zetnet.co.uk (Chris Crosskey)
Date: Mon, 18 Jan 1999 22:51:31 GMT
Subject: Amp schemos....
Message-ID: <199901182251.WAA09656@irwell.zetnet.co.uk>

Hi Folks, 
I know this is a  bit OT see ing  as how us high-tech electronica nuts are 
supposed to look  down onl lowly  spankers  of the plank (guitarists 
:-))....but does anyone have the schemos or an  URL for the Session 
Sessionette,  not the current one the  ld one....my  brothers is giving 
grief, though we're lost as  to why as everything appears to  be OK  in 
terms  of components....


Many thanks

chrisc



From DubbleDub at aol.com  Tue Jan 19 00:43:31 1999
From: DubbleDub at aol.com (DubbleDub at aol.com)
Date: Mon, 18 Jan 1999 18:43:31 EST
Subject: Info needed on the JLcooper MIDInterface i/o
Message-ID: <11cee8ba.36a3c723@aol.com>

This is a 1 rackspace MIDI to CV converter,
with 8 gates & 8 CV 1/4" jacks on the front panel.

Does anyone have info on the modes available?
JL Cooper has yet to return my email.

Thankyou



From djblue at asu.edu  Tue Jan 19 00:59:12 1999
From: djblue at asu.edu (Reverend bluE)
Date: Mon, 18 Jan 1999 16:59:12 -0700 (MST)
Subject: reversed transistors.
Message-ID: <Pine.GSO.3.96.990118165632.20552F-100000@general1.asu.edu>


I'm still wondering the bad stuff that would happen when I hooked up one of
the 2N3904's and the 2N4392 backwards.  I've fixed these problems (re-soldered
the parts the way they *should* be) but I still only get a radio station and
no waves in the outputs...

so could I have blown an op-amp, the tranny itself, or a cap in this process
of powering the things wrong?  should they be replaced?  is there an easy way
to test the bits?
-b




From pinknoiz at pinknoiz.com  Tue Jan 19 01:19:30 1999
From: pinknoiz at pinknoiz.com (Bob Gonsalves)
Date: Mon, 18 Jan 1999 16:19:30 -0800
Subject: 19 in rack panel sources?
In-Reply-To: <000501be4314$77a10200$2c15d7d0@johns.oei.com>
Message-ID: <v04020a03b2c97f7c9aee@[207.21.142.116]>

>Does anybody know of a source of blank 19" w x 17.5" h rack panels painted
>black in the USA?  Mouser has what I need in white and grey but no black.
>(Too lazy to paint)

SESCOM http://www.sescom.com/  might have something in their enclosures
catalog. I know their stuff is blank&black, I don't know if they sell just
the faceplates. They have audio products, too, which is always fun to look
at for the DIY'er.
-Bob Gonsalves http://www.pinknoiz.com/




From mirwin1 at istar.ca  Tue Jan 19 01:20:20 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Mon, 18 Jan 1999 19:20:20 -0500
Subject: Pre-distortion Diodes for Moog Ladder Filter
References: <36A2EBC1.7D51@swipnet.se> <199901181938.UAA14602@mail2.it.kth.se>
Message-ID: <36A3CFC3.27666F5F@istar.ca>

Hi,
Rather than trying to "clean up" the Moog ladder filter, it would be
more interesting to take a good quality, high S/N 24 dB/oct VCF and be
able to add a controlled amount of a pleasant-sounding "Moog" form of
distortion to it ( without the noise).. From other discussions on the
net, it seems that the "classic" sound of this vcf is due to 3 things a)
it is 24 dB/oct instead of  12 dB/oct  b) the characteristic distortion
(including even-harmonic cancellation due to the symmetrical structure)
and c) internal filtering of the distortion products. Any thoughts on
this?




From Romeo_Fahl at stream.com  Tue Jan 19 02:24:57 1999
From: Romeo_Fahl at stream.com (Romeo_Fahl at stream.com)
Date: Mon, 18 Jan 1999 17:24:57 -0800
Subject: MS20 Filter Question
Message-ID: <852566FE.00079AD1.00@galaxy.support.stream.com>



What does the opamp in the cv control section do for the circuit?

(http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/schematics/KLM-307.GIF)





From varner at k-online.com  Tue Jan 19 02:45:39 1999
From: varner at k-online.com (Steve Varner)
Date: Mon, 18 Jan 1999 17:45:39 -0800
Subject: Switching FET (was 4859/4391/4392)
Message-ID: <36A3E3C0.8ABE25BD@k-online.com>

After I posted my query I did some searching. I found a Phillips
transistor cross reference on the net and it said that the KE4859 was
replaceable by an ECG467. This is the same as the NTE467 (available in
many places). Gene recommended the NTE466 which is of course very
similar. I also found the ECG467 used in some online VCO's (eg. MAXX
VCO's) as well as the 2N4391 and 2N4392. I was informed privately that
the 4391 is more similar to the KE4859. I think any fast switch of this
type would probably do OK.

SV




From vco at mindspring.com  Tue Jan 19 03:02:25 1999
From: vco at mindspring.com (tomg)
Date: Mon, 18 Jan 1999 21:02:25 -0500
Subject: reversed transistors.
Message-ID: <199901190208.VAA20017@smtp2.mindspring.com>



----------
> From: Reverend bluE <djblue at asu.edu>
> To: DIY <synth-diy at mailhost.bpa.nl>
> Subject: reversed transistors.
> Date: Monday, January 18, 1999 6:59 PM
> 
> 
> I'm still wondering the bad stuff that would happen when I hooked up one
of
> the 2N3904's and the 2N4392 backwards.  I've fixed these problems
(re-soldered
> the parts the way they *should* be) but I still only get a radio station
and
> no waves in the outputs...
> 
> so could I have blown an op-amp, the tranny itself, or a cap in this
process
> of powering the things wrong?  should they be replaced?  is there an easy
way
> to test the bits?
> -b
The fet should be ok. Test the npn like this...
-Set your multi-meter on RX1 and zero the meter. Digital diode-check
mode is the same kind of thing. Look for a good reading to be .6 or .7.
leads may be reversed on some meters just make sure it tests good one
way or the other.
-Put the neg-lead on the 2N3904s base the meter should move about 1/3
of the scale when the collector or emitter is connected to the pos-lead.  
-Put the pos-lead on the base and the meter should not move at all when
putting the neg-lead to the collector or emitter, if it does it's leaky.
-Last test the collector-emitter junction both ways the meter should not 
move at all, if it does it's leaky.
-At any point if the meter deflects full scale the transistor is shorted.

In circuit working adjust the cv so 120mv is on the base of the input 
transistor, it should be close to +10 on the collector side of the 1K5 
resistor, about -.55mv on the emitters and near .4mv at the collector
hi-scale trimmer junction. 




From varner at k-online.com  Tue Jan 19 03:14:18 1999
From: varner at k-online.com (Steve Varner)
Date: Mon, 18 Jan 1999 18:14:18 -0800
Subject: Subsonic Death Rays (is now way-OT)
References: <Pine.GSO.4.05.9901181045580.26670-100000@walrus.itlabs.umn.edu>
Message-ID: <36A3EA76.4597EC97@k-online.com>

You should have heard the rumble I got out of my little "Energy" subwoofer with
a recent LFO prototype. I thought there was an earthquake....

I bet that elephants would be unhappy with those sonic death rays!
Now *this* is really off topic... I once saw a documentary film (PBS) where they
used subaudible elephant mating calls to attract elephants for filming. You
should have seen the guys run when the elephant ran to the truck with the
speakers!  ;-)



M wIlson wrote:

> I happen too know first hand that "Rollers" (people dosed on the
> drug ecstacy) absolutely can not take a good shot of bass to the belly.I have
> used low-low frequency sine waves for a bassline or two on on more than a
> few occasions. Makes rollers sick to their stomachs. I have never seen so
> many people participate in synchronized vomiting in my life. Gross, but
> fun! (most of the flies near my home are missing wings :)
> Gawd, couldn't get much more off topic than that.
>
>                          The Family Werks presents...
>                           Performing live at "Love"
>                 Valentine's day weekend in Minneapolis, MN USA
>              ****Sonic Boom of Love featuring Clarissa Fragile*****
>                (also Boo WIlliams and some other big-name chumps)






From mamundso at mr.net  Tue Jan 19 04:14:50 1999
From: mamundso at mr.net (Mark Amundson)
Date: Mon, 18 Jan 1999 19:14:50 -0800
Subject: Amp schemos....
References: <199901182251.WAA09656@irwell.zetnet.co.uk>
Message-ID: <36A3F8AA.2453@mr.net>

Go to the AMPAGE website and ask the question in one of their amp
forums.

Mark Amundson,
and fellow plank spanker

Chris Crosskey wrote:
> 
> Hi Folks,
> I know this is a  bit OT see ing  as how us high-tech electronica nuts are
> supposed to look  down onl lowly  spankers  of the plank (guitarists
> :-))....but does anyone have the schemos or an  URL for the Session
> Sessionette,  not the current one the  ld one....my  brothers is giving
> grief, though we're lost as  to why as everything appears to  be OK  in
> terms  of components....
> 
> Many thanks
> 
> chrisc



From djblue at asu.edu  Tue Jan 19 04:36:36 1999
From: djblue at asu.edu (Reverend bluE)
Date: Mon, 18 Jan 1999 20:36:36 -0700 (MST)
Subject: HOORAY!
Message-ID: <Pine.GSO.3.96.990118203330.11657D-100000@general1.asu.edu>


thank you everybody for the help.  I am now the proud parent of a VCO!  I had
two trannies hooked up wrong, and I was missing a bit of trace, but now, I get
sounds from all the outputs.  

Unfortunately, I don't have anything that outputs a CV and/or gate to test the
'VC' part of the 'O'.  Is there anyway that I can simulate a CV to see what
happens?  What would happen if I connected a AA (1.5 volt) battery to the CV
in?  I just got it working so I don't want to blow it away by doing something
horrible...
again, thanks to everyone!
-ben




From vco at mindspring.com  Tue Jan 19 04:55:39 1999
From: vco at mindspring.com (tomg)
Date: Mon, 18 Jan 1999 22:55:39 -0500
Subject: AW: PAIA Hex VCA circuit
Message-ID: <199901190400.XAA28622@camel8.mindspring.com>

One of the guys on the list sent me this a few months
ago. I think it may be what your talking about.

http://www.mindspring.com/~vco/misc/hexvca.gif

tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
---------------------------------------------------------------------------




From aschrock at cs.brandeis.edu  Tue Jan 19 06:27:58 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 19 Jan 1999 00:27:58 -0500 (EST)
Subject: HOORAY!
In-Reply-To: <Pine.GSO.3.96.990118203330.11657D-100000@general1.asu.edu>
Message-ID: <Pine.HPP.3.95.990119002509.22527B-100000@bay.cs.brandeis.edu>

You can just take a potentiometer and hook the middle connector up to the
input (in series with a resistor, remember! Typically 100k to a summing 
opamp..) with the other connectors hooked up to +15v and -15v
respectively. Don't you do this already with the "tune" pot on the VCO? 

Also realize this doesn't help in scaling the unit at all... 

Andrew

-| Andrew Schrock | aschrock at cs.brandeis.edu |-

On Mon, 18 Jan 1999, Reverend bluE wrote:

> 
> thank you everybody for the help.  I am now the proud parent of a VCO!  I had
> two trannies hooked up wrong, and I was missing a bit of trace, but now, I get
> sounds from all the outputs.  
> 
> Unfortunately, I don't have anything that outputs a CV and/or gate to test the
> 'VC' part of the 'O'.  Is there anyway that I can simulate a CV to see what
> happens?  What would happen if I connected a AA (1.5 volt) battery to the CV
> in?  I just got it working so I don't want to blow it away by doing something
> horrible...
> again, thanks to everyone!
> -ben
> 
> 




From zzynt at swipnet.se  Tue Jan 19 08:05:11 1999
From: zzynt at swipnet.se (BJ)
Date: Mon, 18 Jan 1999 23:05:11 -0800
Subject: AW: PAIA Hex VCA circuit
References: <1BF5E20E0C4DD111BBAB00805FE2D5820120C521@nbgm336a.nbgm.siemens.de> <199901182012.VAA14933@mail2.it.kth.se>
Message-ID: <36A42EA7.1DFE@swipnet.se>

Magnus Danielson wrote:

> This is exactly how I preceived it. I would feed the input with CV
> through a 100 kohm resistor and also feed the signal into the input
> through a 100 kohm resistor, this way would the N-channel MOSFET be
> linearized. If you do not feed too hot signals on this, it will act in
> the linear region of the FET curve, so it would actually work as well
> as a single FET, but here you got 6 of them wired up for a fairly
> small price. Important not is however that this only works well with
> the unbuffered 4069, the buffered one is not as fun (to say the least).
> 
> It's wild, it's hilarious... got to try just for the sake of it ;)
> 
> Cheers,
> Magnus

Quite interesting this hexa VCA thing, i had a fast 
look into Don Lancaster "filter book" and there is
a short description on how to use "various" things as
a voltage controlled resistor.

One of them is a Mosfet and there Don is suggesting a 1Mohm for feed
back
to get the device more linear, he also mention this about to "rework"
a 4049 to do the same thing but hexa times!

I just had a wery short look at the 4069 as well but 
the input protection diodes may cause troubbles!!

How about using the Vdd pin as an AM modulation input??(Ohh!) ;)

BJ



From vco at mindspring.com  Tue Jan 19 08:16:15 1999
From: vco at mindspring.com (tomg)
Date: Tue, 19 Jan 1999 02:16:15 -0500
Subject: Fw: AW: PAIA Hex VCA circuit
Message-ID: <199901190721.CAA15994@camel8.mindspring.com>

-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------

----------
> From: tomg <vco at mindspring.com>
> To: Toby Paddock <tpaddock at seanet.com>
> Subject: Re: AW: PAIA Hex VCA circuit
> Date: Tuesday, January 19, 1999 2:15 AM
> 
> -----------
> > From: Toby Paddock <tpaddock at seanet.com>
> > To: 'tomg' <vco at mindspring.com>
> > Subject: RE: AW: PAIA Hex VCA circuit
> > Date: Tuesday, January 19, 1999 12:42 AM
> > 
> > Nope, doesn't seem to be there.  (404)
> > --Toby
> > 
> Sorry Try..
> 
> http://www.mindspring.com/~vco/misc/pics/hexvca.gif
> > ----------
> > From: 	tomg[SMTP:vco at mindspring.com]
> > Sent: 	Monday, January 18, 1999 7:55 PM
> > To: 	synth-diy at mailhost.bpa.nl
> > Subject: 	Re: AW: PAIA Hex VCA circuit
> > 
> > One of the guys on the list sent me this a few months
> > ago. I think it may be what your talking about.
> > 
> > http://www.mindspring.com/~vco/misc/hexvca.gif
> > 
> > tg
> >
>
--------------------------------------------------------------------------
> > Mad Mouse - PC Board - Analog For Everybody
> > http://www.mindspring.com/~vco/madm/mm_order.html
> >
>
---------------------------------------------------------------------------
> > 
> > 
> > 



From Colin.Fraser at scottishpower.plc.uk  Tue Jan 19 10:09:44 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Tue, 19 Jan 1999 09:09:44 -0000
Subject: AW: PAIA Hex VCA circuit
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2C2@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: BJ [mailto:zzynt at swipnet.se]
> Sent: 19 January 1999 07:05
> To: Magnus Danielson
> Cc: diylistan
> Subject: Re: AW: PAIA Hex VCA circuit
> 
> Quite interesting this hexa VCA thing, i had a fast 
> look into Don Lancaster "filter book" and there is
> a short description on how to use "various" things as
> a voltage controlled resistor.
> 
> One of them is a Mosfet and there Don is suggesting a 1Mohm for feed
> back
> to get the device more linear, he also mention this about to "rework"
> a 4049 to do the same thing but hexa times!
> 
> I just had a wery short look at the 4069 as well but 
> the input protection diodes may cause troubbles!!
> 
> How about using the Vdd pin as an AM modulation input??(Ohh!) ;)


Another novel use of the 4069 is in the Roland Tr909.
Have a look at the schematic for the Snare drum (
http://hardware.freepage.de/raf909/ , circuit analysis, snare drum...)

Follow the schematic from the label ENV1.
There are two voltage controlled oscillators built around a 4069 IC. The
supply voltage to the chip is modulated to produce pitch modulation of the
oscillators by the envelope signal.

The toms use the same idea, but with an extra osc.

Colin f




From grbridgw at facstaff.wisc.edu  Tue Jan 19 11:12:51 1999
From: grbridgw at facstaff.wisc.edu (Gary R.Bridgwater)
Date: Tue, 19 Jan 1999 04:12:51 -0600
Subject: PLEASE remove
Message-ID: <3.0.2.32.19990119041251.0071bea8@facstaff.wisc.edu>

>Date: Fri, 01 Jan 1988 00:43:13 -0600
>To: <synth-diy at mailhost.bpa.nl>
>From: "Gary R.Bridgwater" <grbridgw at facstaff.wisc.edu>
>Subject: PLEASE remove
>
>Please remove grbridgw at facstaff.wisc.edu from your synth-diy email send
list. Thank you. 
>
>



From chris at scp.de  Tue Jan 19 11:13:46 1999
From: chris at scp.de (Christian Hofmann)
Date: Tue, 19 Jan 1999 11:13:46 +0100
Subject: Thomas part numbers
In-Reply-To: <36A38A09.15C0@chelt.ac.uk>
References: <36A38A09.15C0@chelt.ac.uk>
Message-ID: <199901191013.LAA23001@dilbert.scp.de>

On Mon, 18 Jan 1999 19:22:49 +0000
James Dunn <s9610068 at chelt.ac.uk> wrote:

> 	Could anyone enlighten me on some Thomas chips from the
Troubadour
> Organ? They use their own part numbers:
> 
> 13-5045-6; LSI 101 Keyer, 
> 13-5027-6; LSI Rhythm counter, and 
> 13-5032-6; LSI Features.

Hi,
if there's an "AY" prefix these look like some 70s part numbers,
frequency dividers and such, including some dedicated chips for musical
instruments. No relation to SSM, AFAIK.

I think the manufacturer was General Instruments. Haven't heard of those
chips for years now though.

cu
Christian




From Juergen.Haible at nbgm.siemens.de  Tue Jan 19 12:01:04 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 19 Jan 1999 12:01:04 +0100
Subject: AW: MS20 Filter Question
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201232F36@nbgm336a.nbgm.siemens.de>

	>What does the opamp in the cv control section do for the circuit?

> (http://www.hyperreal.org/music/machines/manufacturers/Korg/MS-synths/sche
> matics/KLM-307.GIF)
> 
> 
Servo loop for keeping the reference current of the
expo converter constant. It's like an "ordinary" expo
converter as found in many VCOs, only turned upside
down. (Current source rather than current sink)

JH.



From Juergen.Haible at nbgm.siemens.de  Tue Jan 19 12:36:27 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 19 Jan 1999 12:36:27 +0100
Subject: CEM3340 sync results
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201232FBA@nbgm336a.nbgm.siemens.de>

Hi,

last night I have finally made an A / B comparison between
the CEM3340 + external transistor sync and "normal" sync
of a saw VCO.

The 3340 circuit (VCO 1) can be found at
<http://www.it.kth.se/~e93_mda/synths/friends/haible/hj2vco.gif>.
The 6-position switch is in its most right position, selecting the
external pnp transistor that is connected to pin 10 of the
3340. This is very similar to what was suggested in the 3340
data sheet, and what is implemented in Rev. 3 Prophet 5,
OB-Xa, OB-8 and probably in some other synths, too.

The Saw VCO circuit (VCO2) is a clone of the Oberheim SEM VCO.
A picture of the original should be at the Synthfool page. In this circuit
the VCO's capacitor is discharged by an external sync pulse, just
as it would be in it's next own cycle.

I hooked up the two VCOs for identical frequency, and for identical
modulation depth (minimal beat rate, without sync). Then I sync'ed
both VCOs to the same (3rd) VCO and started to compare the
outputs of VCO 1 and VCO 1.

I compared them by ear, by cancellation, and by scope.

For comparison by ear, I applied various envelopes to both VCOs
at the same time, and switched between the VCO outputs.
I used long, manually triggered envelopes as well as short LFO
triggered ones.
At first, I thought there was no audible difference at all. After doing
the other tests, I heard a difference in sound, too, but it was
very minimal, and hard to decide which one would be "better".

For comparison by cancellation I inverted the output of VCO1
and connected the two VCO outputs to the two ends of a
potentiometer and monitored the signal at the wiper. I adjusted
the pot for best canellation of the two signals. Without modulation
(i.e. at the same frequency as the sync'ing 3rd VCO) I got almost
perfect cancellation. There was a minimal difference between the
two saw waves, because VCO2 had a tiny flat portion after the
capacitor discharge. The triangle-based 3340 doesn't have this, so
one could even say the 3340 has the more perfect saw wave. But
the difference was minimal, and I had to turn up the volume to
hear the difference signal at all.
Things changed with modulation applied. As I increased the
frequency of both VCOs simultanously, there was a noticable
difference signal. Still rather quiet, but not neglible. (I made sure
that this was not due to mistracking of the VCOs in the unsync'ed
case - otherwise I'd have different waveforms in the sync'ed case
even from two identical VCOs).

So there was clearly a small difference. I checked with the scope,
and I saw what I had seen before, but never spent too much thought
about it:
The 3340 + single transistor does indeed emulate the ordinary
saw-type sync function. BUT the level to which the capacitor
is discharged / charged does not exactly result in a "reset to
zero" for the saw case. In fact there is some "overshot" that looks
like a capacitor in a saw VCO would not be discharged to 0V,
but rather be slightly reverse charged to -200mV or so. On the
saw output of a a sync'ed 3340 you have several "normal" saw 
cycles, then one unfinished cycle as the sync pulse strikes
(just as in the normal saw VCO), then one normal cycle
with *slightly* larger than normal amplitude, and so on.

So here you have the difference. It's clearly there, but it's hardly
audible. And it's so far from the 3340's internal "hard sync" that
one can say that this one external transistor does an excellent
job to emulate "normal" hard sync.

How comes this difference ? I can only guess that it has to do with
the level to which the external pnp is tied. It's probably hard to hit 
the exact point of discharge asymptode to get a perfect "return to
zero" after the triangle-saw conversion. But I would not be surprised
if you could hit that exact point if you use a trimpot and an opamp
buffer to adjust the voltage to a slightly different voltage near -5V.
I have not tried this, and I won't, because for me the sync is close
enough, but I encourage you to try it if you want to know for sure.

JH.



From IXQY at aol.com  Tue Jan 19 13:14:01 1999
From: IXQY at aol.com (IXQY at aol.com)
Date: Tue, 19 Jan 1999 07:14:01 EST
Subject: Ultrasonic Death Ray?  (was: Subsonic Death Rays)
Message-ID: <2ceb9c04.36a47709@aol.com>

In a message dated 99-01-18 14:56:52 EST, magnus at analogue.org writes:

<< Here in Sweden a new such device has been built, so that you may send
 <a directed subsonic boom onto a person in order to temporarilly
 <disable them from anything possibly dangerous. FOA showed of such a
 <device in the national TV channel news, and they thought it could be
 <usefull in peace keeping missions, especially to control civilans.>>

  Don't doctors use high intensity ultrasonic beams to physically shatter
kidney stones in people's abdomens? (I seem to remember reading this long
ago.) This procedure supposedly breaks up the stones into smaller, less
painful sizes.
 It's seems like ultrasonic technology could be used for the same peace
keeping missions that are mentioned above.
 On the other hand, if you press the "wrong" button you could wind up with an
angry mob of people with bad haircuts....

 Andrew Sanchez



From jorgen.bergfors at idg.se  Tue Jan 19 13:16:27 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 19 Jan 1999 13:16:27 +0100
Subject: PCB layout, Art or Craft?
Message-ID: <TFSJXAAC@idg.se>

> >> 4. I can have beautiful full color parts placement diagrams. My parts
> symbols look
> >> almost exactly like the real parts.
> >>>You make PCB or painting for art gallery?
> > I'm only in it for the art. Music is art and I want my synthesizer
 to be a piece of art too. I have seen too many homebuilt synths that look like piles of junk. >> /Jorgen
> I'm sure you want your synth to look good,who doesn't,yet the very
>nature of a modular synth is that it can Never be said to be finished..... >You will probably want to modify most of your PCB's and add extra holes to >front panels for add-on pots/switches six months after finishing the final >module as various mods/improvements come to mind through using the synth.I >find this happens to me with most of the modules i've built,
>  So i guess that at some stage you will have to choose between having a cool >looking synth that you consider Art [personally i think that any homebuilt >synth that works is Art],or a sprawling monster of a slowly evolving/mutating >mess that sounds exactly as you want it to....the latter is probably quite an >accurate description of my modular/Monster synth.

>i wish you well in your synth-building activities
>Paul H

I do rather extensive research before I build a module. That's one of the activities I enjoy the most with this hobby. First I decide what features and functions I want. Then I design the front panel. After that I try to find or design the circuits. Then I build a prototype of the circuits that I am not familiar with. Only after that I build the actual module.
So  there is seldom a need for changes after the module is completed. And anyway there is usually no room on the front panel for additional knobs, switches or jacks. If I'm not satisfied, I'd rather build a brand new module than change an existing one. You can never get too many modules, so the old one is still useful. Isn't this the beauty with the modular concept?

/Jorgen





From martin.czech at intermetall.de  Tue Jan 19 13:39:21 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 19 Jan 1999 13:39:21 +0100 (MET)
Subject: CEM3340 sync results
Message-ID: <199901191239.NAA02340@window.intermetall.de>

> Hi,
> 
> last night I have finally made an A / B comparison between
> the CEM3340 + external transistor sync and "normal" sync
> of a saw VCO.

A VERY INTERESTING MESSAGE SNIPPED.

Makes sense.
How would you describe 3340 "external" sync versus "internal mode".
I'd say rough versus unspectacular, or something.
A good idea to have both possibilities.


One aditional question:

The 3340 is an integrator triangle osc. That means that the saw must
be constructed via a polarity switch (this is the "reverse" function of
a rectifier, which is used for saw->tri conversion, funny isn't it?).
The so constructed saw has *almost* double frequency (it is not perfect,
ie. there is still a fundamental frequency component left, because of
polarity switch imperfection). Now the triangle direction switch signal,
alias square is added to the saw, and there you are, a proper 1:1 saw
wave, but it should have a glitch and/or step where the square skips.

Ar shorter: all tri->saw converters should give a saw with a glitch/step.

Is this correct, or are there better methods?
Could you see any such artefacts on the 3340 saw wave?

I think the step could be avoided by proper trimming the square level and
offset, but the glitch ? 

How could it be done in the 3340, there is no trim pin for that.
Low bandwidth buffer ?

m.c.




From Juergen.Haible at nbgm.siemens.de  Tue Jan 19 13:52:28 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 19 Jan 1999 13:52:28 +0100
Subject: AW: CEM3340 sync results
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820123310E@nbgm336a.nbgm.siemens.de>

	>Ar shorter: all tri->saw converters should give a saw with a
>glitch/step.
	>
	>Is this correct, or are there better methods?
	>Could you see any such artefacts on the 3340 saw wave?
	>
	>I think the step could be avoided by proper trimming the square
level >and
	>offset, but the glitch ? 
	>
	>How could it be done in the 3340, there is no trim pin for that.
	>Low bandwidth buffer ?

Just two guesses: Trimming probably not required
because of a clever circuit where drifting volatges cancel.
(It's on one chip after all). Glitch probably smoothed with
limited slew rate (rather than limited band width) stage.

Just guesses - I never tried to investigate further because
it is no problem in a practical VCO. If there are some
remnants of a glitch it will hurt much less on a signal
of high harmonic content (saw) than on a "dark" triangle.

JH.




From martin.czech at intermetall.de  Tue Jan 19 14:13:13 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 19 Jan 1999 14:13:13 +0100 (MET)
Subject: AW: CEM3340 sync results
Message-ID: <199901191313.OAA02417@window.intermetall.de>

> Just two guesses: Trimming probably not required
> because of a clever circuit where drifting volatges cancel.
> (It's on one chip after all). Glitch probably smoothed with
> limited slew rate (rather than limited band width) stage.
> 
> Just guesses - I never tried to investigate further because
> it is no problem in a practical VCO. If there are some
> remnants of a glitch it will hurt much less on a signal
> of high harmonic content (saw) than on a "dark" triangle.
> 
I'm sorry, was in a hury in my first mail.

The reason for a closer look to the glitch is not audio,
but waveshaping, a/d converters etc. They could be disturbed by 
even an inaudible glitch in the saw, which might cause very audible
artefacts in the waveshaper etc.

But perhaps it is better to use tri waves only for waveshapers,
in order to avoid the saw discharge glitch problems as well.

m.c.




From Colin.Fraser at scottishpower.plc.uk  Tue Jan 19 14:18:21 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Tue, 19 Jan 1999 13:18:21 -0000
Subject: CEM3340 sync results
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2C4@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 19 January 1999 11:36
> To: DIY
> Subject: CEM3340 sync results
> 
> last night I have finally made an A / B comparison between
> the CEM3340 + external transistor sync and "normal" sync
> of a saw VCO.

Weird, I did a very similar thing last night too - I compared the normal
3340 sync with the data sheet external transistor method and also with the
E&MM Spectrum method that uses a 2N3819 FET to discharge the 3340 timing cap
directly.
The Spectrum has two sync modes. The first is a normal reset to 0, the
second resets the wave to the halfway point - so it continues in the same
direction. I only implemented the reset to 0 method, but I will try out the
halfway option to see if it adds anything worthwhile.
A nice possibilty here is to have a reset level input, to allow 1 vco to
sync another vco to the instantaneous position of yet another vco.
Don't know how this would sound...
BTW from the Spectrum article I found that the timing cap on the 3340 sits
at about 1.6v at its lowest level - this voltage is dropped by the buffer
stage. 

The end results of my tests were much the same as Juergens.
The internal 'hard' and 'soft' sync modes of the 3340 are pretty awful for
'sync' effects - they are really only of use for locking two oscillators
together.
The external transistor methods both produce very similar results - so close
as to be identical, and they sound very much like the sync effects on the
Prodigy which I used for comparison. In normal use I wouldn't expect there
to be any advantage to either oscillator type.
I still prefer sync effect sounds on my Prodigy, but I guess this is not
because of any audible difference in the output of the oscillators, but more
probably the effect of distortion and filtering.

Colin f







From jorgen.bergfors at idg.se  Tue Jan 19 14:21:39 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 19 Jan 1999 14:21:39 +0100
Subject: AN-32
Message-ID: <TFSJZFWW@idg.se>

Hi DIYers!

Have anybody checked out the NS AN-32? It contains a large number of useful-looking FET circuits. Among other things a VCA that consists of just three FETs, two trimmers and one capacitor. Yes, it uses the elusive 2N4391.

/Jorgen




From edusilva at bahianet.com.br  Tue Jan 19 15:09:36 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Tue, 19 Jan 1999 12:09:36 -0200
Subject: Subsonic Death Rays (even more OT!)
Message-ID: <199901191411.MAA08744@postman.bahianet.com.br>

Magnus Danielson <magnus at analogue.org> wrote:

 
> Well, this is by no means new.
> 
> Here in Sweden a new such device has been built, so that you may send
> a directed subsonic boom onto a person in order to temporarilly
> disable them from anything possibly dangerous. FOA showed of such a
> device in the national TV channel news, and they thought it could be
> usefull in peace keeping missions, especially to control civilans.
> 
> I have heard about an old British military device that where intended
> to work in the battle field.

 
Years ago, I read about a "sound gun" developed by the nazis during the II
World War. It was a cannon that could shot directed bursts of air. It was
capable to break thick wood boards many meters away. Luckly, this secret
weapon didn't worked well...

Edu 
_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil





From M.Rogers at cs.ucl.ac.uk  Tue Jan 19 16:02:56 1999
From: M.Rogers at cs.ucl.ac.uk (Michael ROGERS)
Date: Tue, 19 Jan 1999 15:02:56 +0000
Subject: Ultrasonic Death Ray? (was: Subsonic Death Rays)
In-Reply-To: Your message of "Tue, 19 Jan 1999 07:14:01 EST." <2ceb9c04.36a47709@aol.com>
Message-ID: <199901191503.QAA24127@mailhost.bpa.nl>


><< Here in Sweden a new such device has been built, so that you may send
> <a directed subsonic boom onto a person in order to temporarilly
> <disable them from anything possibly dangerous. FOA showed of such a
> <device in the national TV channel news, and they thought it could be
> <usefull in peace keeping missions, especially to control civilans.>>

> It's seems like ultrasonic technology could be used for the same peace
>keeping missions that are mentioned above.
> On the other hand, if you press the "wrong" button you could wind up with an
>angry mob of people with bad haircuts....

Or a crowd of people being vomited on by elephants with kidney stones.

This is turning into another Monty Python thread, isn't it?

Michael Rogers



From b.layer at chaff.vikingelectronics.com  Tue Jan 19 18:02:56 1999
From: b.layer at chaff.vikingelectronics.com (Bill Layer)
Date: Tue, 19 Jan 1999 11:02:56 -0600
Subject: HARP project - Ultrasonic US death ray.
In-Reply-To: <199901191503.QAA24127@mailhost.bpa.nl>
References: <Your message of "Tue, 19 Jan 1999 07:14:01 EST." <2ceb9c04.36a47709@aol.com>
Message-ID: <3.0.6.32.19990119110256.007d8d10@192.168.210.18>

Hey,

So who knows anything about the HARP (High Altitude Research) project. It
is supposed to be a dangerous magneto-electro/acoustic energy source.

It's purpose is shrouded in mystery. It is claimed to be a weather control
project, but meterologists dispute the veracity of the government's
assertion. It seems much more like a population control project, as the
frequencies it is capable of producing have been proven to disorient and
disable humans and animals.

In fact, the gov did a study on it a few years ago...

I'm sure the web is littered with conspiracies on the project.




Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

NOTE: When replying, remove the word 
"chaff." from my email address. No spam!



From a-davidh at microsoft.com  Tue Jan 19 20:02:46 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Tue, 19 Jan 1999 11:02:46 -0800
Subject: HARP project - Ultrasonic US death ray.
Message-ID: <C35556591D34D111BB5600805F1961B90BBEAFF0@RED-MSG-47>

HAARP - High-frequency Active Auroral Research Program
http://server5550.itd.nrl.navy.mil/haarp.html

They are using a phased array radar to "boink" the ionosphere and see what
happens ( measurements of conductivity and size ).  There is also a lot of
general geophysical instrumentation at the site.

There is an even more powerful system in Tromso Norway that has been online
for several years, the telescope at Arecibo does ionospheric radar work,
there is also a group at Liecester University, United Kingdom that is
studying actual Ionospheric heating - they are pumping enough RF to raise
the temperature appreciably...


So basically, HAARP isn't unique by a long shot, the military's own web site
pretty much details what they are doing ( there are public tours if you want
to make the trip to check it out ), HAARP is not fully online yet and there
are other groups pumping much more energy into the ionosphere and have been
for several years ( ten ).




-----Original Message-----
From: Bill Layer [mailto:b.layer at chaff.vikingelectronics.com]
Sent: Tuesday, January 19, 1999 9:03 AM
To: Michael ROGERS; synth-diy at mailhost.bpa.nl
Subject: HARP project - Ultrasonic US death ray.


Hey,

So who knows anything about the HARP (High Altitude Research) project. It
is supposed to be a dangerous magneto-electro/acoustic energy source.

It's purpose is shrouded in mystery. It is claimed to be a weather control
project, but meterologists dispute the veracity of the government's
assertion. It seems much more like a population control project, as the
frequencies it is capable of producing have been proven to disorient and
disable humans and animals.

In fact, the gov did a study on it a few years ago...

I'm sure the web is littered with conspiracies on the project.




Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

NOTE: When replying, remove the word 
"chaff." from my email address. No spam!



From cwiitala at jpusa.chi.il.us  Tue Jan 19 20:50:45 1999
From: cwiitala at jpusa.chi.il.us (Chris Wiitala)
Date: Tue, 19 Jan 1999 13:50:45 -0600
Subject: Synth building kits
Message-ID: <3.0.1.32.19990119135045.00685c6c@mailbox.jpusa.net>

Does anyone know of a "homemade analog synth-building kit"? I'm looking to
build something like the ARP Solina String Ensamble or the Logan Strings.
Mainly I want the strings to sound as real as possible for analog. If you
can help me write: cwiitala at jpusa.chi.il.us
Thanks-Christopher W.



From gerryd at ntx-tech.com  Tue Jan 19 21:32:34 1999
From: gerryd at ntx-tech.com (Gerry Dahl)
Date: Tue, 19 Jan 1999 14:32:34 -0600
Subject: Mods for the PAIA Fatman
Message-ID: <003701be43ea$dac05a80$0d01a8c0@gerry-bill.internal>

Hi Everyone,
What is the best way to setup a sqarewave output on the fatman?
I would like to have it setup with a switch for tri-sqare.
Thanks.
Gerry Dahl





From oakley at techrepairs.freeserve.co.uk  Tue Jan 19 21:35:55 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Tue, 19 Jan 1999 20:35:55 -0000
Subject: Pre-distortion Diodes for Moog Ladder Filter
Message-ID: <010e01be43ec$d2183fe0$5816883e@default>

BJ said:
What seems to bee an gained parameter in theory is in reality drovned in
noise!!Thats the problem with the Moog filter, "its noisy" as hell and
as son as levels are shifted you add noise.

Tony says: On this I will disgaree. In my tests on various filters last
year, I found the Moog to be the quietest I tested. The LM13700 or
3080/FET arrangements were noisier, both in audio band hiss and CV
breakthrough. Only by trimming every stage in the two part SVF could you
hope to get rid of the CV breakthrough. In the end I abandoned using a
SVF with OTAs because of noise. A ladder made from well matched top and
bottom pairs, and a decent diff amp is far quieter to my ears. And it
doesn't sound horrible (get ready to duck) when you overdrive it. As a
audio processor the Moog filter is better. However, there are better
OTAs around. Perhaps by using THAT DBX vcas and op-amps, you would get a
better VCF as a SVF, but the cost is prohibitive.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html








From pinknoiz at pinknoiz.com  Tue Jan 19 21:50:59 1999
From: pinknoiz at pinknoiz.com (Bob Gonsalves)
Date: Tue, 19 Jan 1999 12:50:59 -0800
Subject: HARP project - Ultrasonic US death ray.
In-Reply-To: <3.0.6.32.19990119110256.007d8d10@192.168.210.18>
References: <199901191503.QAA24127@mailhost.bpa.nl> <Your message of "Tue,
 19 Jan 1999 07:14:01 EST." <2ceb9c04.36a47709@aol.com>
Message-ID: <v04020a01b2ca9f58389a@[207.21.142.104]>

>So who knows anything about the HARP (High Altitude Research) project. It
>is supposed to be a dangerous magneto-electro/acoustic energy source.
...
>
>I'm sure the web is littered with conspiracies on the project.

Note the corrected spelling below.

Two completely different perspectives are at:

http://w3.nrl.navy.mil/projects/haarp/index1.html

http://www.earthpulse.com/products/haarp.html

Personally, I'd just as soon the military didn't even look into these sort
of experiments.
Bob Gonsalves, Research Director, Pink Noise Studios
Art*Technology*Politics  http://www.pinknoiz.com/




From mirwin1 at istar.ca  Wed Jan 20 02:33:22 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Tue, 19 Jan 1999 20:33:22 -0500
Subject: Pre-distortion Diodes for Moog Ladder Filter
References: <010e01be43ec$d2183fe0$5816883e@default>
Message-ID: <36A53262.D961E3C6@istar.ca>

Tony,
Thanks for the info gleaned from  your first-hand experience with
building Moog VCF's. I agree with you that the distortion from these
filters is not unpleasant and in reality is probably an essential
component of the overall sound of the filter. Software synths that
attempt to emulate the Moog filter need to consider the distortion
characteristics as well. The distortion I can live with; it's the
background hiss that is annoying. On your VCF schematic I see that you
have used some very low-noise, well-matched components. In OTA filters,
the linearizing diodes are effective in improving the S/N, but when
distortion occurs it happens very suddenly, which is not a desirable
characteristic. Does good matching of the top and bottom pairs
significantly reduce the noise ( I can see that it is essential for
minimizing CV feedthrough) or is the noise reduction mainly a
consequence of the LM394 being a very low-noise part?




From smart at nn.com  Wed Jan 20 03:05:15 1999
From: smart at nn.com (Mark Smart)
Date: Tue, 19 Jan 1999 20:05:15 -0600 (EST)
Subject: AW: PAIA Hex VCA circuit
In-Reply-To: <BA865FF10473D211BC6F00805F0D830702D2C2@catsprntp01.cat.scottishpower.plc.uk> from "Fraser, Colin J" at Jan 19, 99 09:09:44 am
Message-ID: <199901200205.UAA30230@medusa.nn.com>

(In German accent) THE TIME HAS COME TO DRAW.

Here is one-sixth of the PAIA hex VCA circuit in question. You guys pretty
much guessed it:

Control in >---////--+--////-------+------+
0-5V           4.7k  |  100K       |      |
                     /             /      /
                100K /        100K /      / 4.7M
                     |             /      /
                    gnd            |      |
                                V+ |      |
                                |  |      |
                                /  |      |
                            50K /<-+      |
                                /         |
                                |         |
                               gnd        |
                                          |
                           +-------///----+
                           |       4.7M   |
                           |              |
           22K             |              |
Audio in >--///--+---------+-----o<|------+
                 /               1/6 4049
                 / 270 ohm
                 /
                 |
                gnd


Here's the single mixed output:

4049 pins 1& 8
|     
|     
|     15K
+-----///-------+
|               |   15pF between 1 & 8 on op-amp
|     |\        |
|     | \       |
|-----|- \      |
      |   \     |   22uF
      |    >----+---| |-----output
      |   /         +  -
 gnd--|+ / LM301
      | /
      |/

I tried running 0-15V pulse and square waves into it, and when the
volume is down really low, the output looks like:

_____        ______
     |      |
     |      |
     |______|
     |
     | 

And sounds just as bad. This happens even if you just run one square wave
into it at a time, so I don't think it's a just crosstalk problem. I tried
changing the 4.7M resistors to 2.2 Megs, and changing the voltage divider
on the audio input to 100K and 470 ohms. This seemed to 
help a little, but did not get rid of the problem on all channels.
Also I tried putting 68uF caps on the audio inputs to remove the DC offset
of the square waves. No good. Also tried removing pin 1 from the output to
the op-amp (this introduces another transistor into the circuit which
doesn't really need to be there. I think), no good.

I think maybe this circuit is just too nonlinear to have much dynamic
range. I would appreciate suggestions on how to improve it, but I've pretty
much decided just to build a bunch of ARP VCA's, which aren't all that
complicated. 




************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     And Musician                             *
*     smart at medusa.nn.com                      *
************************************************



From thelab at sprint.ca  Wed Jan 20 05:27:46 1999
From: thelab at sprint.ca (Philip)
Date: Wed, 20 Jan 1999 01:27:46 -0300
Subject: Multimoog help (Osc Problem)
References: <199901180721.IAA21718@window.intermetall.de>
Message-ID: <36A55B42.360@sprint.ca>

I put this multimoog on the back burner for a year  (infact I swapped
it's ps board with a dud in a frined's micromoog ) but now another owner
has the same problems...by chance has anyone else seen this?

My old email to AH:
>Hi,I'm investigating a problem with my Multimoog. Initially I guessed itwas 
>simply an opamp blown in the osc mixing circuit....reason:everything works 
>except no osc output. Filter tracking, resonance,modulation routings, white 
>noise, ribbon, bender..etc all work.I just got the schematics Friday and pulled 
>it apart. No +750mV on pin one of Osc B CA3046 but rather -1Vish. As well the Osc 
>Sum voltage at IC301a pin1 is typically at -1 or -2V and rises above +4V when 
>you apply modulations and go up the keyboard(1/V oct is there). The Osc Node 
>(1Oct/10uA) current applied to  IC301A pin 2 floats at 0V and does not change in 
>voltage (I expected to see some change!) I'm guessing that since it is a current 
>source that the voltage is regulated? I'm going to throw a grenade in and simply 
>replace all of the active parts of the exp. current generators but I find it 
>weird that Osc A and B are both dead on the synth...I can't find a common 
>denominator. Any insight into this synth would be appreciated...I spent half my 
>time figuring out the butchered Micromoog schematics and undocumented tracecuts 
>on the synth.
> best regards Philip
 
Recent Email:
I'm Hendrik Kr?ger (from Germany), and since a month I have exactly the
same probem you had at the end of
1997. Even the current on IC301 is the same.
It seams to me, that it is a typical problem of that synth.
 
I would be verry happy, if you culd remember what the problem was. 
Im also looking for Multimoog schematics, if you know where i can get
them, it would be nice,

Philip
-- 
Philip Pilgrim                  The Lab Audio Works
5 Evan's Drive                  - Analog/Digital Recording/Processing
Hammonds Plains                 - Computer/Synth Interfacing
Nova Scotia, Canada             - Hardware/Software Development
B4B 1M8

Phone     +1.902.835.7844
Email      mailto:thelab at sprint.ca

Web Page: http://www.robotnik.com/the_lab



From stew at uq.net.au  Wed Jan 20 06:41:24 1999
From: stew at uq.net.au (Stewart Pye)
Date: Wed, 20 Jan 1999 16:41:24 +1100
Subject: Mods for the PAIA Fatman
In-Reply-To: <003701be43ea$dac05a80$0d01a8c0@gerry-bill.internal>
Message-ID: <199901200647.QAA01727@uq.net.au>

At 14:32 19/01/99 -0600, Gerry Dahl wrote:
>Hi Everyone,
>What is the best way to setup a sqarewave output on the fatman?
>I would like to have it setup with a switch for tri-sqare.
>Thanks.
>Gerry Dahl
> 

The most flexible way is to use a comparator on the saw waveform to get a
pulse width modulation signal. The other input to the comparator goes to a
voltage source to set the pulse width. I think there's a schematic on the
web somewhere for this. It's very simple.
You could take the pulse wave straight off the 555 but it's probably not
square. 


actually, I think there's a schem here somewhere. follow links:


http://www.tomg.vivid.net/

hope this helps.
stewart pye




From irish at eskimo.com  Wed Jan 20 09:39:49 1999
From: irish at eskimo.com (Irish)
Date: Wed, 20 Jan 1999 00:39:49 -0800
Subject: Common supply
References: <006101be4451$9f683900$09784e0c@hpcustomer>
Message-ID: <99012000401306.05535@Pandemonium>

Crowbar circuit? 

Irish

On Wed, 20 Jan 1999, you wrote:
>No, it's a GOOD idea, IMHO!  Put in a crowbar circuit for overvoltage
>protection,
>so if the big supply goes awry, it won't ruin everything.
>
>-Art (thawing out from a five-day power outage)
>
>-----Original Message-----
>From: Irish <irish at eskimo.com>
>To: DIY <synth-diy at mailhost.bpa.nl>
>Date: Sunday, January 17, 1999 7:01 PM
>Subject: Common supply
>
>
>>Like everyone else I'm sure, I am amassing this collection of warts on my
>>wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just wire
>>everything to it? (9V because almost everything I have is 9V)
>>Is this a Bad Idea?
>>
>>Thanks,
>>Irish
>>
>>BTW, I got my Midi Thru box done - worked first pass (almost; had a bunk
>chip
>>but not my fault).
>>



From theremin1 at worldnet.att.net  Wed Jan 20 09:48:15 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 20 Jan 1999 00:48:15 -0800
Subject: Common supply
Message-ID: <006101be4451$9f683900$09784e0c@hpcustomer>

No, it's a GOOD idea, IMHO!  Put in a crowbar circuit for overvoltage
protection,
so if the big supply goes awry, it won't ruin everything.

-Art (thawing out from a five-day power outage)

-----Original Message-----
From: Irish <irish at eskimo.com>
To: DIY <synth-diy at mailhost.bpa.nl>
Date: Sunday, January 17, 1999 7:01 PM
Subject: Common supply


>Like everyone else I'm sure, I am amassing this collection of warts on my
>wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just wire
>everything to it? (9V because almost everything I have is 9V)
>Is this a Bad Idea?
>
>Thanks,
>Irish
>
>BTW, I got my Midi Thru box done - worked first pass (almost; had a bunk
chip
>but not my fault).
>




From chris at scp.de  Wed Jan 20 10:57:54 1999
From: chris at scp.de (Christian Hofmann)
Date: Wed, 20 Jan 1999 10:57:54 +0100
Subject: Common supply
In-Reply-To: <99012000401306.05535@Pandemonium>
References: <006101be4451$9f683900$09784e0c@hpcustomer> <99012000401306.05535@Pandemonium>
Message-ID: <199901200957.KAA16307@dilbert.scp.de>

On Wed, 20 Jan 1999 00:39:49 -0800
Irish <irish at eskimo.com> wrote:

> Crowbar circuit? 

That's an overvoltage detector that burns a PSU fuse to protect the gear
connected. I think it's called crowbar because it's a pretty brutal
circuit, e.g. triggering a thyristor in parallel to PSU output, i.e.
simply shortening it. Better to blow up a fuse (or even the PSU) than a
bunch of synths.

Btw, I'm a bit reluctant to replacing a couple of wws by a single PSU.
All those warts have separate grounds, this doesn't have to be signal
ground. Worst case would be a device having the wart's + connected to
signal ground. Even in other cases there could be a ground loop. And then
there are AC warts as well...
Call me nuts, but separate wall warts are part of a healthy ground setup.

cu
Christian

> On Wed, 20 Jan 1999, you wrote:
> >No, it's a GOOD idea, IMHO!  Put in a crowbar circuit for overvoltage
> >protection,
> >so if the big supply goes awry, it won't ruin everything.
> >
> >-Art (thawing out from a five-day power outage)
> >
> >-----Original Message-----
> >From: Irish <irish at eskimo.com>
> >To: DIY <synth-diy at mailhost.bpa.nl>
> >Date: Sunday, January 17, 1999 7:01 PM
> >Subject: Common supply
> >
> >
> >>Like everyone else I'm sure, I am amassing this collection of warts on my
> >>wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just wire
> >>everything to it? (9V because almost everything I have is 9V)
> >>Is this a Bad Idea?
> >>
> >>Thanks,
> >>Irish




From martin.czech at intermetall.de  Wed Jan 20 11:08:05 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 20 Jan 1999 11:08:05 +0100 (MET)
Subject: archive : too much work with links
Message-ID: <199901201008.LAA10100@window.intermetall.de>

Due to my constant work overload I'll be not able to collect and review
all the links from the diy-list mails any more. It's simply too much,
allone the year 1998 has 1500 links in the list! (But I'll finish the
allready ongoing saerch for links for 1995-1998, never the less)

So, if you think YOU HAVE SOMETHING INTERESTING and you want a link
in the Diy Grey Pages, I'd ask you to send me a mail, with the link,
very short description (one line), and page title (your name etc).

Thank you !

m.c.





From Juergen.Haible at nbgm.siemens.de  Wed Jan 20 12:33:49 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 20 Jan 1999 12:33:49 +0100
Subject: AW: Pre-distortion Diodes for Moog Ladder Filter
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820125730D@nbgm336a.nbgm.siemens.de>

Everybody seems to have a different opinion about the Moog
filter - here's mine.

I love it in my Minimoog (Clone). In conjunction with raw VCO
waveform input and a brilliantly designed nonlinear VCA at the 
output it  produces a wonderful smooth and silky tone, and I 
never ever would adress it as "noisy".
As a processing device for complex external signals, I don't
like it at all. Neither the filter of my Mini Clone, nor the new
Moogerfooger one (Sorry). Almost any other filter I have makes
a (IMO) better processing device. Speaking of 4pole filters,
the Moog doesn't come close to a 2040 for that purpose.
2-pole filters like the Wasp or SEM filter are great, too. (But
these *are* noisy)

Just my opinion, of course. 

JH.




From Juergen.Haible at nbgm.siemens.de  Wed Jan 20 13:13:46 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 20 Jan 1999 13:13:46 +0100
Subject: AW: Common supply
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582012573C5@nbgm336a.nbgm.siemens.de>

	>Btw, I'm a bit reluctant to replacing a couple of wws by a single
PSU.
	>All those warts have separate grounds, this doesn't have to be
signal
	>ground. Worst case would be a device having the wart's + connected
to
	>signal ground. Even in other cases there could be a ground loop.
And then
	>there are AC warts as well...
	>Call me nuts, but separate wall warts are part of a healthy ground
setup.

Call you nuts ? This was the first sane answer to this question.

JH.




From jbrookes at bluebear.freeserve.co.uk  Wed Jan 20 19:22:07 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Wed, 20 Jan 1999 18:22:07 -0000
Subject: Looking for Juno-106 parts
Message-ID: <006601be44a3$2c59e740$01010101@aardvark>

Anyone know a source of the following parts to fix a busted Roland Juno-106
(trying to help somebody off-list). Not sure if they're Roland specific
parts or some general ICs

ref.:    15229817OA (maybe the 'O' must be a '0').
name:    ALQH80017A





From Barry.L.Klein at wdc.com  Wed Jan 20 19:33:39 1999
From: Barry.L.Klein at wdc.com (Barry L Klein)
Date: Wed, 20 Jan 1999 10:33:39 -0800 (Pacific Standard Time)
Subject: Common supply
Message-ID: <ISSMTP.1.3(1).19990120103339.4294106679B@Corp.wdc.com>

Another approach you may want to consider is one I mentioned before -
using TVSD's, which are transient protection diodes, much like big zeners.
 They just solder across the supply in question and will clamp
overvoltages beyond the part's spec'd clamp voltage.  They are very fast
and probably would do everything the crowbar circuit would, maybe faster. 
The crowbar detects an overvoltage, fires an SCR to short out the supply
to ground.  If you don't have protection fuses the supply may fry as a
result, depending on its design.  The TVSD would clamp overvoltages to a
fixed voltage level.  Momentary spikes get clamped and your circuit
continues functioning - no fuse gets blown and all is well.  But if your
supply dies and results in overvoltage, the TVSD will clamp and hopefully
the fuse opens.  If you don't have a fuse the TVSD will probably get hot
enough to fry your pcb or melt its solder connections, fall off, and then
all your remaining parts would fry too.  We use them on drive designs here
at WDC and it has resulted in a much reduced failure rate of the various
IC's.  

You can get TVSD's from Digikey and Mouser I think.  A 5V part will clamp
slightly over 7 volts, a 12V part at 17 volts or so.  Much cheaper - no
heatsink required for an SCR for example.

These are not MOV's and don't degrade with time, BTW.

Barry


>
The idea here is that if some fault causes the power supply unit to 
put out too much voltage (say a resistor failure somwhere) then a SCR
produces a short circuit across the output, hopefully triggering
another current limiting ckt to shut down the PSU.. it doesn't have to
be destructive.
When the SCR triggers, it looks like a crowbar, resistance wise.







From magnus at analogue.org  Wed Jan 20 20:20:58 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 20 Jan 1999 20:20:58 +0100
Subject: AW: PAIA Hex VCA circuit
In-Reply-To: Your message of "Mon, 18 Jan 1999 22:55:39 -0500"
References: <199901190400.XAA28622@camel8.mindspring.com>
Message-ID: <199901201920.UAA03208@mail2.it.kth.se>

>>>>> "t" == tomg  <vco at mindspring.com> writes:

 t> One of the guys on the list sent me this a few months
 t> ago. I think it may be what your talking about.

 t> http://www.mindspring.com/~vco/misc/hexvca.gif

Yes, but the URL is
http://www.mindspring.com/~vco/misc/pics/hexvca.gif

It's complete with linearizing and offset trimming.

Cheers,
Magnus



From magnus at analogue.org  Wed Jan 20 20:44:10 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Wed, 20 Jan 1999 20:44:10 +0100
Subject: HARP project - Ultrasonic US death ray.
In-Reply-To: Your message of "Tue, 19 Jan 1999 11:02:56 -0600"
References: <3.0.6.32.19990119110256.007d8d10@192.168.210.18>
Message-ID: <199901201944.UAA03342@mail2.it.kth.se>

>>>>> "BL" == Bill Layer <b.layer at chaff.vikingelectronics.com> writes:

 BL> Hey,
 BL> So who knows anything about the HARP (High Altitude Research) project. It
 BL> is supposed to be a dangerous magneto-electro/acoustic energy source.

 BL> It's purpose is shrouded in mystery. It is claimed to be a weather control
 BL> project, but meterologists dispute the veracity of the government's
 BL> assertion. It seems much more like a population control project, as the
 BL> frequencies it is capable of producing have been proven to disorient and
 BL> disable humans and animals.

 BL> In fact, the gov did a study on it a few years ago...

 BL> I'm sure the web is littered with conspiracies on the project.

Well, if we are talking about the same HARP project, it is a project
where they took two navy canon tubes and mounted one on top of the
other, so that you got effectively the double length. With this they
set new altitude records for canons.

Later did one of the main engineers for the HARP project construct a
supergun for Saddam Hussein in Iraq, actually he made a smaller one
first. The actual pipes where built in GB and the gun-powder came from
Italy (if I recall things right). They had the small gun fire a couple
of times. The big gun was never completed for firing, the Desert Storm
and UN inspectors came in and put a stop to that, but before this
Israeli Mossad agents had the engineer killed at his home in Belgium.

Cheers,
Magnus



From a-davidh at microsoft.com  Wed Jan 20 23:13:27 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Wed, 20 Jan 1999 14:13:27 -0800
Subject: HARP project - Ultrasonic US death ray.
Message-ID: <C35556591D34D111BB5600805F1961B90BBEB00F@RED-MSG-47>

http://www.bullatomsci.org/issues/1992/o92/o92.reviews.html  for a review of
the book: "Bull's Eye: The Assassination and Life of Supergun Inventor
Gerald Bull"

http://www.world.std.com/~jlr/doom/bull.htm brief biography and picture



-----Original Message-----
From: Magnus Danielson [mailto:magnus at analogue.org]
Sent: Wednesday, January 20, 1999 11:44 AM
To: b.layer at chaff.vikingelectronics.com
Cc: M.Rogers at cs.ucl.ac.uk; synth-diy at mailhost.bpa.nl
Subject: Re: HARP project - Ultrasonic US death ray.


>>>>> "BL" == Bill Layer <b.layer at chaff.vikingelectronics.com> writes:

 BL> Hey,
 BL> So who knows anything about the HARP (High Altitude Research) project.
It
 BL> is supposed to be a dangerous magneto-electro/acoustic energy source.

 BL> It's purpose is shrouded in mystery. It is claimed to be a weather
control
 BL> project, but meterologists dispute the veracity of the government's
 BL> assertion. It seems much more like a population control project, as the
 BL> frequencies it is capable of producing have been proven to disorient
and
 BL> disable humans and animals.

 BL> In fact, the gov did a study on it a few years ago...

 BL> I'm sure the web is littered with conspiracies on the project.

Well, if we are talking about the same HARP project, it is a project
where they took two navy canon tubes and mounted one on top of the
other, so that you got effectively the double length. With this they
set new altitude records for canons.

Later did one of the main engineers for the HARP project construct a
supergun for Saddam Hussein in Iraq, actually he made a smaller one
first. The actual pipes where built in GB and the gun-powder came from
Italy (if I recall things right). They had the small gun fire a couple
of times. The big gun was never completed for firing, the Desert Storm
and UN inspectors came in and put a stop to that, but before this
Israeli Mossad agents had the engineer killed at his home in Belgium.

Cheers,
Magnus



From cstecker at ovenguard.com  Wed Jan 20 23:30:30 1999
From: cstecker at ovenguard.com (Chris Stecker)
Date: Wed, 20 Jan 1999 14:30:30 -0800
Subject: Buchla Garage Sale!
Message-ID: <v02110100b2cc05c5fe87@[205.134.244.161]>

DIY'ers and Analogue freaks:

Here's a unique opportunity to acquire some truly historical instruments
from Don Buchla.  Analog and hybrid digital/analog gear from the 100, 200,
300, and 400 series is available, including many functional units as well
as some intriguing DIY possibilities.  Send them an email to get a copy of
the list of available items, and check out the "historical" section of
Buchla's website (www.buchla.com) for descriptions and specifications of
nearly all the old Buchla gear.

-Chris

---------------

BUCHLA & ASSOCIATES GARAGE SALE

A few 100 and 200 series modules, and parts thereof, have been
discovered in the proverbial garage, and will be offered for sale. If you'd
care to make an offer on some truly vintage equipment, please send us
your email or snailmail address, and we'll forward a compilation of
available goodies, along with our estimates of condition, completion, and
operability.

Please email contact info to: gsale at buchla.com.

---------------





From bduggan at netcom.com  Thu Jan 21 01:20:57 1999
From: bduggan at netcom.com (Brett Duggan)
Date: Wed, 20 Jan 1999 16:20:57 -0800 (PST)
Subject: Mods for the PAIA Fatman
In-Reply-To: <003701be43ea$dac05a80$0d01a8c0@gerry-bill.internal>
Message-ID: <Pine.3.89.9901201631.A10457-0100000@netcom10>


Hi Gerry,

Scott Gravenhorst has an excellent FatMan Mod site that contains this 
mod as well.  The URL for it is:

	http://www.teklab.com/~chordman/

Good luck,
Brett D

> Hi Everyone,
> What is the best way to setup a sqarewave output on the fatman?
> I would like to have it setup with a switch for tri-sqare.
> Thanks.




From rcsnyder at wave.net  Thu Jan 21 05:10:33 1999
From: rcsnyder at wave.net (R. Charles Snyder)
Date: Wed, 20 Jan 1999 20:10:33 -0800
Subject: [sdiy] theremin questions
References: <005201c1ce30$075ef420$a12f2bd1@oemcomputer>
Message-ID: <000701be44f3$ff9eee20$4b3207d0@rcsnyder>

I was wandering if I could put an etherwave theremin through various pedals,
and/or put a keyboard (such as a DX7) through the theremin to tweak the
sound of my keyboard. Also if I put the theremin through a pedal (preferably
a series of guitar pedals) would it be over modulated and make a god awful
sound.



From vco at mindspring.com  Thu Jan 21 06:30:06 1999
From: vco at mindspring.com (tomg)
Date: Thu, 21 Jan 1999 00:30:06 -0500
Subject: AW: PAIA Hex VCA circuit
Message-ID: <199901210538.AAA17508@camel8.mindspring.com>



----------
> From: Magnus Danielson <magnus at analogue.org>
> To: vco at mindspring.com
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: AW: PAIA Hex VCA circuit
> Date: Wednesday, January 20, 1999 2:20 PM
> 
> >>>>> "t" == tomg  <vco at mindspring.com> writes:
> 
>  t> One of the guys on the list sent me this a few months
>  t> ago. I think it may be what your talking about.
> 
>  t> http://www.mindspring.com/~vco/misc/hexvca.gif
> 
> Yes, but the URL is
> http://www.mindspring.com/~vco/misc/pics/hexvca.gif
> 
> It's complete with linearizing and offset trimming.
> 
> Cheers,

Good! You found it.

-tg

> Magnus



From theremin1 at worldnet.att.net  Thu Jan 21 08:29:33 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 20 Jan 1999 23:29:33 -0800
Subject: Common supply
Message-ID: <013f01be450f$cb49f400$40784e0c@hpcustomer>

The single, well regulated 9v supply has been a proven
effective solution for powering a least a dozen FX pedals
simultaneously.  Of course, one must be mindful of correct
load polarity!

-Art

-----Original Message-----
From: Christian Hofmann <chris at scp.de>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Wednesday, January 20, 1999 4:04 AM
Subject: Re: Common supply


>On Wed, 20 Jan 1999 00:39:49 -0800
>Irish <irish at eskimo.com> wrote:
>
>> Crowbar circuit?
>
>That's an overvoltage detector that burns a PSU fuse to protect the gear
>connected. I think it's called crowbar because it's a pretty brutal
>circuit, e.g. triggering a thyristor in parallel to PSU output, i.e.
>simply shortening it. Better to blow up a fuse (or even the PSU) than a
>bunch of synths.
>
>Btw, I'm a bit reluctant to replacing a couple of wws by a single PSU.
>All those warts have separate grounds, this doesn't have to be signal
>ground. Worst case would be a device having the wart's + connected to
>signal ground. Even in other cases there could be a ground loop. And then
>there are AC warts as well...
>Call me nuts, but separate wall warts are part of a healthy ground setup.
>
>cu
>Christian
>
>> On Wed, 20 Jan 1999, you wrote:
>> >No, it's a GOOD idea, IMHO!  Put in a crowbar circuit for overvoltage
>> >protection,
>> >so if the big supply goes awry, it won't ruin everything.
>> >
>> >-Art (thawing out from a five-day power outage)
>> >
>> >-----Original Message-----
>> >From: Irish <irish at eskimo.com>
>> >To: DIY <synth-diy at mailhost.bpa.nl>
>> >Date: Sunday, January 17, 1999 7:01 PM
>> >Subject: Common supply
>> >
>> >
>> >>Like everyone else I'm sure, I am amassing this collection of warts on
my
>> >>wall/floor/etc. Any reason I can't get/make a 9V 3A supply and just
wire
>> >>everything to it? (9V because almost everything I have is 9V)
>> >>Is this a Bad Idea?
>> >>
>> >>Thanks,
>> >>Irish
>




From theremin1 at worldnet.att.net  Thu Jan 21 08:37:43 1999
From: theremin1 at worldnet.att.net (Arthur Harrison)
Date: Wed, 20 Jan 1999 23:37:43 -0800
Subject: Common supply
Message-ID: <015401be4510$ef694740$40784e0c@hpcustomer>

Crowbars are usually intended to prevent drastic 
consequences from gross, permanent supply faults, 
not transients.  Agreed that MOVs can be effective 
protection from spurious noise.

-Art

-----Original Message-----
From: Barry L Klein <Barry.L.Klein at wdc.com>
To: SYNTH-DIY at mailhost.bpa.nl <SYNTH-DIY at mailhost.bpa.nl>
Date: Wednesday, January 20, 1999 12:17 PM
Subject: RE: Re: Common supply


>Another approach you may want to consider is one I mentioned before -
>using TVSD's, which are transient protection diodes, much like big zeners.
> They just solder across the supply in question and will clamp
>overvoltages beyond the part's spec'd clamp voltage.  They are very fast
>and probably would do everything the crowbar circuit would, maybe faster. 
>The crowbar detects an overvoltage, fires an SCR to short out the supply
>to ground.  If you don't have protection fuses the supply may fry as a
>result, depending on its design.  The TVSD would clamp overvoltages to a
>fixed voltage level.  Momentary spikes get clamped and your circuit
>continues functioning - no fuse gets blown and all is well.  But if your
>supply dies and results in overvoltage, the TVSD will clamp and hopefully
>the fuse opens.  If you don't have a fuse the TVSD will probably get hot
>enough to fry your pcb or melt its solder connections, fall off, and then
>all your remaining parts would fry too.  We use them on drive designs here
>at WDC and it has resulted in a much reduced failure rate of the various
>IC's.  
>
>You can get TVSD's from Digikey and Mouser I think.  A 5V part will clamp
>slightly over 7 volts, a 12V part at 17 volts or so.  Much cheaper - no
>heatsink required for an SCR for example.
>
>These are not MOV's and don't degrade with time, BTW.
>
>Barry
>
>
>>
>The idea here is that if some fault causes the power supply unit to 
>put out too much voltage (say a resistor failure somwhere) then a SCR
>produces a short circuit across the output, hopefully triggering
>another current limiting ckt to shut down the PSU.. it doesn't have to
>be destructive.
>When the SCR triggers, it looks like a crowbar, resistance wise.
>
>
>
>




From rob at secret-secret.com  Thu Jan 21 08:55:20 1999
From: rob at secret-secret.com (Rob)
Date: Wed, 20 Jan 1999 23:55:20 -0800
Subject: Buchla Garage Sale!
In-Reply-To: <v02110100b2cc05c5fe87@[205.134.244.161]>
Message-ID: <v04003a0eb2cc8da1497d@[38.28.75.113]>

Yeah I emailed that addy about a month ago when someone else posted about
it.  I've still gotten no reply.

-Rob-

Secret Secret
http://secret-secret.com


At 2:30 PM -0800 1/20/99, Chris Stecker wrote:
>DIY'ers and Analogue freaks:
>
>Here's a unique opportunity to acquire some truly historical instruments
>from Don Buchla.  Analog and hybrid digital/analog gear from the 100, 200,
>300, and 400 series is available, including many functional units as well

<snip>

>Please email contact info to: gsale at buchla.com.





From stew at uq.net.au  Thu Jan 21 08:58:21 1999
From: stew at uq.net.au (Stewart Pye)
Date: Thu, 21 Jan 1999 18:58:21 +1100
Subject: LM 13600 question
Message-ID: <199901210904.TAA14478@uq.net.au>

Hi All,

I'm building a filter based on the MS 20. I was wondering if it's safe to
use just a series resistor (15k) for the bias input (as in the data sheet)
and have this coming off the wiper of a 10k pot?? I want to try it like
this before I build the expo converter. I don't want to keep blowing up LM
13600's. I'm missing a few pages from the data sheet.

Thanks

Stewart Pye




From THEKn0TiS at aol.com  Thu Jan 21 10:23:35 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Thu, 21 Jan 1999 04:23:35 EST
Subject: n e one got a copy of rebirth 2.0 they want to sell
Message-ID: <e13cb1e5.36a6f217@aol.com>

i just checked out version 2.0 and would like to get it if anyone has a copy i
would like to buy it,..



From jorgen.bergfors at idg.se  Thu Jan 21 10:57:22 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 21 Jan 1999 10:57:22 +0100
Subject: LM 13600 question
Message-ID: <TFSNMOUB@idg.se>

Yes, it is safe, as long as the pot isn't connected to more than 15 volts. But you won't get a linear response this way. I guess that isn't a problem in your case, but it explains why such a simple circuit is not used in real designs.

/Jorgen





MIME:stew at uq.net.au on 99-01-21 10:51:59
To:  synth-diy at mailhost.bpa.nl @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: LM 13600 question 

Hi All,

I'm building a filter based on the MS 20. I was wondering if it's safe to
use just a series resistor (15k) for the bias input (as in the data sheet)
and have this coming off the wiper of a 10k pot?? I want to try it like
this before I build the expo converter. I don't want to keep blowing up LM
13600's. I'm missing a few pages from the data sheet.

Thanks

Stewart Pye










From jbrookes at bluebear.freeserve.co.uk  Thu Jan 21 12:03:15 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Thu, 21 Jan 1999 11:03:15 -0000
Subject: Synth-DIY=dead??
Message-ID: <000001be4543$c0444ea0$01010101@aardvark>

>well is there any "easy" MS10 or MS20 mod?


I had the idea a while ago (still sadly un-implemented) of adding a divider
to a MS-10 oscillator and then routing this sub-octave to the normalised
side of the external input jack. Then the external signal level control
would control the amount of sub-octave added in when nothing is plugged into
the external input socket. It means that there would be no permanent
alteration to the Korg. Could always use something else instead of divider:
a timbre altering circuit, sine shaper, frequency doubler, phase locked loop
for a seconds gliding weird oscillator...





From jbrookes at bluebear.freeserve.co.uk  Thu Jan 21 12:14:49 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Thu, 21 Jan 1999 11:14:49 -0000
Subject: soundcard midi/joystick port adapter question
Message-ID: <000101be4543$c1715cf0$01010101@aardvark>


>where do i get the adapter that lets me plug it into midi devices like a
tg33
>or a hs60 for instance or plug midi devices into it,... i have ytried music
>stores and computer stores no one seems to know where i would get such a
>creature i know what it looks like it has one end that plugs into the game
>port and one end that lets a standard midi cable plug into it (i immagine)


There are schematics available on the web to build your own (I think I saw
some on Hyperreal once).





From Juergen.Haible at nbgm.siemens.de  Thu Jan 21 12:34:28 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 21 Jan 1999 12:34:28 +0100
Subject: AW: LM 13600 question
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58201257F29@nbgm336a.nbgm.siemens.de>

	>I'm building a filter based on the MS 20. I was wondering if it's
safe to
	>use just a series resistor (15k) for the bias input (as in the data
sheet)
	>and have this coming off the wiper of a 10k pot?? I want to try it
like
	>this before I build the expo converter. I don't want to keep
blowing up LM
	>13600's. I'm missing a few pages from the data sheet.

One resistor for both halves of the 13600 is ok. (It is *not* for two
separate
3080's, BTW.)
A 10k log pot is fine for tests, but you'll have a dead range at the low end
that
is also temperature sensitive.

Hey, everybody's building "new version" MS-20 filters now (;->) 
Count me in ! (As soon as I find the time).

JH.




From THEKn0TiS at aol.com  Thu Jan 21 14:15:28 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Thu, 21 Jan 1999 08:15:28 EST
Subject: question about a roland hs60
Message-ID: <4f5ded44.36a72870@aol.com>

i got my hs60 today it has 1 dead voice i have located the 80017a chips in it
under the keyboard,...I have only a voltimeter and a continuity tester as far
as diagnostic tools go,..

.anyone with half a clue as to how i would go about determining witch of these
odd chips (80017a vca/vcf) is a dud <>?? 

also thier is a juno 106/hs60 expansion board with a sterio and audio input
<scratch scratch> now what is this is it an audio input for the filter<>? im a
little wary about pluging an audio signal into it for fear of burning
something out ,...,..



From merlin at ion.com.au  Thu Jan 21 14:56:39 1999
From: merlin at ion.com.au (Merlin Zener)
Date: Thu, 21 Jan 1999 23:56:39 +1000
Subject: AW: Common supply
References: <1BF5E20E0C4DD111BBAB00805FE2D582012573C5@nbgm336a.nbgm.siemens.de>
Message-ID: <36A73217.69460400@ion.com.au>

Haible Juergen wrote:
> 
>         >Btw, I'm a bit reluctant to replacing a couple of wws by a single
> PSU.
>         >All those warts have separate grounds, this doesn't have to be
> signal
>         >ground. Worst case would be a device having the wart's + connected
> to
>         >signal ground. Even in other cases there could be a ground loop.
> And then
>         >there are AC warts as well...
>         >Call me nuts, but separate wall warts are part of a healthy ground
> setup.
> 
> Call you nuts ? This was the first sane answer to this question.
> 
> JH.


As I wrote a while ago, I used to make up custom made supplies for 
people who needed this kind of thing. I used hand wound toroids
with seperate windings for each rail.

Not cheap...

-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"



From Juergen.Haible at nbgm.siemens.de  Thu Jan 21 15:19:27 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 21 Jan 1999 15:19:27 +0100
Subject: AW: AW: Common supply
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820127D205@nbgm336a.nbgm.siemens.de>

	>As I wrote a while ago, I used to make up custom made supplies for 
	>people who needed this kind of thing. I used hand wound toroids
	>with seperate windings for each rail.
	>
	>Not cheap...

There's a lot that can be done if you know exactly what you're doing,
i.e. if you know the circuit of the boxes you're connecting this way.

I have even seen such a solution from a major stompbox manufacturer
to daisy chain the PS of  _their own_ stomp boxes. They should know
about the polarity of their boxes, and of possible ground loop, too.
So they can savely do this.

But it's still not a good advice to chain random gear that just has written
"9V DC" on it. You can be lucky (probably), or you can destroy something.
I don't mean "you" of course. But what will you do when one of your
customers destroys something ? I wouldn't take that risk.

Every Manufacturer has his disclaimer "only use with dedicated power
supply". A foolish user could connect an unregulated supply and blow
something. A clever 3rd party PSU manufacturer can take precautions
like stabilized voltage to avoid this. So he can savely sell it "for use
on gear with xx Volt / yy Amp input". But how how can you savely
market a supply that's intended for daisy chained connection ?
"Only use on gear of which you have read and understood the schematic 
diagram" ?!

Just think of the legal implications if something burns down.

JH.









From macnutt at westel.net  Thu Jan 21 16:33:07 1999
From: macnutt at westel.net (Phil Macnutt)
Date: Thu, 21 Jan 1999 09:33:07 -0600
Subject: midi keyboard source
Message-ID: <36A748B3.5BA520B@westel.net>

I'm currently looking for an inexpensive midi keyboard to use for synth
projects.
I can get a brand new casio ctk-411 for $99.

Any better way to do this?

Also, what about pitch and mod wheels (ala minimoog).  are these things
available used (or new).  How about making them (warm up the lathe...)




From twist-1 at happy.hardcorps.org  Thu Jan 21 17:05:23 1999
From: twist-1 at happy.hardcorps.org (Jeff Scroggin)
Date: Thu, 21 Jan 1999 10:05:23 -0600 (CST)
Subject: [Digital_Hell] question about a roland hs60
In-Reply-To: <4f5ded44.36a72870@aol.com>
Message-ID: <Pine.LNX.4.02.9901211005000.4792-100000@happy.hardcorps.org>

> 
> also thier is a juno 106/hs60 expansion board with a sterio and audio input
> <scratch scratch> now what is this is it an audio input for the filter<>? im a
> little wary about pluging an audio signal into it for fear of burning
> something out ,...,..
> 
There is??? Anyone have more info on this, and are they still available
anywhere??

Jeff




From Juergen.Haible at nbgm.siemens.de  Thu Jan 21 17:15:19 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 21 Jan 1999 17:15:19 +0100
Subject: AW: AW: Common supply
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820127D43F@nbgm336a.nbgm.siemens.de>

	>As I wrote a while ago, I used to make up custom made supplies for 
	>people who needed this kind of thing. I used hand wound toroids
	>with seperate windings for each rail.
	>
	>Not cheap...

Sorry for my previous answer to Merlin Zener.
I didn't read "separate windings".
So that's basically separate power supplies
sharing only the primary winding, and surely
a good solution.

I vaguely remember we had that topic before.
I just was confused because I got the above mail
from Merlin aparently as an answer to my caveat
on daisy chaining power supplies.

Sorry again for the rambling about burned down
houses and legal stuff, and for the confusion
this may have caused. 

To say it again: What Merlin described is a good
"high end" solution.

JH.



From maf at mcs.net  Thu Jan 21 17:40:15 1999
From: maf at mcs.net (Michael A. Firman)
Date: Thu, 21 Jan 1999 10:40:15 -0600 (CST)
Subject: midi keyboard source (fwd)
Message-ID: <199901211640.KAA31087@Jupiter.mcs.net>

Forwarded message:
> 
> I'm currently looking for an inexpensive midi keyboard to use for synth
> projects.
> I can get a brand new casio ctk-411 for $99.
> 
> Any better way to do this?
> 
> Also, what about pitch and mod wheels (ala minimoog).  are these things
> available used (or new).  How about making them (warm up the lathe...)
> 
> 

Novation used to make a really nice little MIDI keyboard
that came with a wall wart and could also be battery powered.
I don't know if they still make them (check Sweetwater or one
of the other big catalog companies). I have one and it has
a really nice feel and is pretty complete when it comes to 
MIDI functionality. I recall that I paid less than $100 for
it.

------------------------------------------------------------
|Michael A. Firman <maf at mcs.net>
|Naperville, IL USA (finger maf at cluster.mcs.net for PGP key)
|http://www.mcs.net/~maf



From dave.burraston at bt-sys.bt.co.uk  Thu Jan 21 17:46:05 1999
From: dave.burraston at bt-sys.bt.co.uk (Dave Burraston)
Date: Thu, 21 Jan 1999 16:46:05 -0000
Subject: gnuplot ! FOR WINDOWS!!!!
Message-ID: <c=GB%a=_%p=BT%l=ATLAS-990121164605Z-5368@mussel.futures.bt.co.uk>

Martin and list,

I had a windows copy of gnuplot that I had desperately been trying to
locate the binary for on the web. Today I found it :

http://www.geocities.com/SiliconValley/Foothills/6647/


Get the windows version, this has menus....  cool....

Also there is a gnuplot newsgroup comp.graphics.apps.gnuplot

Enjoy!

Cheers, 
Dave B
AKA : jupiter4 at bt-sys.bt.co.uk



From djblue at asu.edu  Thu Jan 21 22:28:45 1999
From: djblue at asu.edu (Reverend bluE)
Date: Thu, 21 Jan 1999 14:28:45 -0700 (MST)
Subject: Question about an op-amp  (NE5517)
Message-ID: <Pine.GSO.3.96.990121142015.16718A-100000@general1.asu.edu>


I was buying parts yesterday, and when I got home I realised that the boy gave
me the wrong op-amps.  Before complaining, I decided to see what it was that
he gave me, and I came upon this description:

NE5517
Dual Operational Transconductance Amplifier
The NE5517 contains two current-controlled transconductance amplifiers, each
with a different input and push-pull output.  The NE5517 offers significant
design and performance advantages over similar devices for all types of
programmable gain applications.  Circuit performance is enhanced through the
use of linearizing diodes at the inputs, which enable a 10dB signal-to-noise
improvement referenced to 0.5%THD.  Preferred in high quality audio
aplications, this circuit features of the NE5517 op-amp include constant
impedance buffers, pin compatibility with the LM13600, excellent matching
between amplifiers and high output signal-to-noise ratio.  This chip is
bundled in a 16-pin DIP package.
=======================================================

Now what I am wondering is if this chip can be used as a substitute to the
LM13600, because I can buy this chip easily and it costs .79 each. (or .70 in
quantities over 49).  

I haven't seen any mention of this chip on any of the web sites that have
designs that use the LM13600 though.  Any info would be helpful!

-ben




From bduggan at netcom.com  Thu Jan 21 22:37:02 1999
From: bduggan at netcom.com (Brett Duggan)
Date: Thu, 21 Jan 1999 13:37:02 -0800 (PST)
Subject: Aluminum box enclosures with perpendicular, not tapered sides?
Message-ID: <Pine.3.89.9901211315.A6147-0100000@netcom10>


Hi guys,

I recently purchased a Hammond diecast aluminum enclosure (part number
1590D, about 7.4"x4.7"x2") to mount a project in.  While the construction
quality of the box is very nice, the sides of it are tapered instead of
perpendicular to the horizontal surfaces, which for me is extremely
frustrating.  (The pictures and dimensions shown in the catalogs are very
misleading.) I was wondering if any of you have come across any high
quality alumimum box enclosures that have truly perpendicular sides?  If
so, can you please provide me with any specific manufacturers/part 
numbers?  Also, do you know if these boxes are offered optionally with 
a baked enamel finish?

Thanks very much for any help,
Brett D




From uzs159 at uni-bonn.de  Thu Jan 21 23:19:29 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Thu, 21 Jan 1999 23:19:29 +0100
Subject: Question about an op-amp  (NE5517)
In-Reply-To: <Pine.GSO.3.96.990121142015.16718A-100000@general1.asu.edu>
Message-ID: <3.0.5.32.19990121231929.008fd1a0@ibm.rhrz.uni-bonn.de>

At 14:28 21.01.99 -0700, you wrote:
>
>I was buying parts yesterday, and when I got home I realised that the boy
gave
>me the wrong op-amps.  Before complaining, I decided to see what it was that
>he gave me, and I came upon this description:
>
>NE5517

>Now what I am wondering is if this chip can be used as a substitute to the
>LM13600, because I can buy this chip easily and it costs .79 each. (or .70 in
>quantities over 49).
>
>I haven't seen any mention of this chip on any of the web sites that have
>designs that use the LM13600 though.  Any info would be helpful!

>From the Datasheet It looks as if it was not only a substitute but really the 
same as LM13700/LM13600. (There are even some drawings identical in both
datasheets!)

Bye
 Rene

             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From halmans at globalxs.nl  Thu Jan 21 23:31:07 1999
From: halmans at globalxs.nl (Maarten Halmans)
Date: Thu, 21 Jan 1999 23:31:07 +0100
Subject: AW: Common supply
References: <1BF5E20E0C4DD111BBAB00805FE2D582012573C5@nbgm336a.nbgm.siemens.de> <36A73217.69460400@ion.com.au>
Message-ID: <36A7AAAB.5E31C79@globalxs.nl>



Merlin Zener wrote:

> As I wrote a while ago, I used to make up custom made supplies for
> people who needed this kind of thing. I used hand wound toroids
> with seperate windings for each rail.
>
> Not cheap...

Mine was cheap, I made such a power supply a couple of years ago. I unwounded the
secondary windings of an old transformer. Then I calculated the number of
windings to get 9 Volt. Rewound it with the desired number of windings per
secondary winding. It had 8 secondary windings, so it took me a lot of afford and
time to get in the old transformer. It worked perfectly. After 3 months the
primary winding broke down because I made a calculation error on the primary
current.
So I use wall warts again.




From a-davidh at microsoft.com  Fri Jan 22 00:20:22 1999
From: a-davidh at microsoft.com (David Halliday (Volt Computer))
Date: Thu, 21 Jan 1999 15:20:22 -0800
Subject: Aluminum box enclosures with perpendicular, not tapered sides
	?
Message-ID: <C35556591D34D111BB5600805F1961B90BBEB02B@RED-MSG-47>

It would be hard to eject the box from the mold if the sides were straight.
The taper is probably more for ease of manufacture than for esthetics...

http://www.sescom.com/enclosure/ - these people have some nice enclosures.
A bit pricey but major quality...  Their audio circuits are of interest too.
Online catalog available via PDF files.



-----Original Message-----
From: Brett Duggan [mailto:bduggan at netcom.com]
Sent: Thursday, January 21, 1999 1:37 PM
To: synth-diy at mailhost.bpa.nl
Subject: Aluminum box enclosures with perpendicular, not tapered sides?



Hi guys,

I recently purchased a Hammond diecast aluminum enclosure (part number
1590D, about 7.4"x4.7"x2") to mount a project in.  While the construction
quality of the box is very nice, the sides of it are tapered instead of
perpendicular to the horizontal surfaces, which for me is extremely
frustrating.  (The pictures and dimensions shown in the catalogs are very
misleading.) I was wondering if any of you have come across any high
quality alumimum box enclosures that have truly perpendicular sides?  If
so, can you please provide me with any specific manufacturers/part 
numbers?  Also, do you know if these boxes are offered optionally with 
a baked enamel finish?

Thanks very much for any help,
Brett D



From cyborg0 at GlobalEyes.net  Fri Jan 22 00:23:35 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Thu, 21 Jan 1999 17:23:35 -0600
Subject: noniverting transistor amp
Message-ID: <36A7B6F7.75ED4329@globaleyes.net>


I need to take a digital signal (5v) and convert it to 12v..
Is this possible to do with 1 transistor amp and maintain phase
relations/non-inverting?

It *seems* like every amp I see is inverting.. 
I guess maybe a darlington configuration would do this, but thats two
trannies..


Rob



From budweiser at ozemail.com.au  Fri Jan 22 02:24:51 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Fri, 22 Jan 1999 11:54:51 +1030
Subject: Aluminum box enclosures with perpendicular, not tapered sides?
Message-ID: <07c701be45a6$04de0760$e2d26ccb@ppp.ozemail.com.au>


-On the subject of enclosures, does anyone have a URL for a company that
makes
desktop boxes, specifically about the size of a TR909? I really need a good
source
for something like this.. :)


<bUd>




From zzynt at swipnet.se  Fri Jan 22 04:41:20 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 21 Jan 1999 19:41:20 -0800
Subject: AW: LM 13600 question
References: <1BF5E20E0C4DD111BBAB00805FE2D58201257F29@nbgm336a.nbgm.siemens.de>
Message-ID: <36A7F360.69C5@swipnet.se>

Haible Juergen wrote:

> One resistor for both halves of the 13600 is ok. (It is *not* for two
> separate
> 3080's, BTW.)
> A 10k log pot is fine for tests, but you'll have a dead range at the low end
> that
> is also temperature sensitive.
> 
> Hey, everybody's building "new version" MS-20 filters now (;->)
> Count me in ! (As soon as I find the time).
> 
> JH.

When you do, why not insert a switch so you can select the 
HP/LP function for each filter,to get a 24 db HP and LP
and a Notch response too besides the usuall BP responce
as in the original design.

And while you are at it why not add another LM13600 so
you get a separate VC Resonance for each filter sektion!

Well, at least i did this in my MAS filter module for the 
Mas system some years ago and im wery pliiised of the performance.

And, yes i do have the original MS 20 VCA in the back of the filter.
(And i still dont think its noisy! >;-)..)
BJ



From zzynt at swipnet.se  Fri Jan 22 04:45:31 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 21 Jan 1999 19:45:31 -0800
Subject: LM13600 multimode filter!
References: <c=GB%a=_%p=BT%l=ATLAS-990121164605Z-5368@mussel.futures.bt.co.uk>
Message-ID: <36A7F45B.752E@swipnet.se>

OSCar multimode filter with a LM13600/13700 at:
http://home8.swipnet.se/~w-88660/schpcb.htm

Just wanted to mention it!

Agusto Pinochet



From varner at k-online.com  Fri Jan 22 07:14:35 1999
From: varner at k-online.com (Steve Varner)
Date: Thu, 21 Jan 1999 22:14:35 -0800
Subject: midi keyboard source
References: <36A748B3.5BA520B@westel.net>
Message-ID: <36A81748.AA3E2C5B@k-online.com>

Musician's Friend usually has pretty good deals. They have Midi
controllers from Roland (A-33, $500), Yamaha (CBXK1, $160 and CBXK2,
$279), and Kaysound (MK-4902, $160). The Yamaha CBXK1 has mini keys (yuk).
The Kaysound board has 49 full size keys with transposition (as does the
Yamaha CBXK2). I haven't been able to find the Yamaha keyboards in the
online catalog though. They may not sell them anymore. They also have
cheap 19" rack rails BTW.

http://www.musiciansfriend.com/

SV

----------------------------------
Phil Macnutt wrote:

> I'm currently looking for an inexpensive midi keyboard to use for synth
> projects.
> I can get a brand new casio ctk-411 for $99.
>
> Any better way to do this?
>
> Also, what about pitch and mod wheels (ala minimoog).  are these things
> available used (or new).  How about making them (warm up the lathe...)






From stew at uq.net.au  Fri Jan 22 08:05:34 1999
From: stew at uq.net.au (Stewart Pye)
Date: Fri, 22 Jan 1999 18:05:34 +1100
Subject: question about a roland hs60
In-Reply-To: <4f5ded44.36a72870@aol.com>
Message-ID: <199901220811.SAA11026@uq.net.au>

At 08:15 21/01/99 -0500, THEKn0TiS at aol.com wrote:
>i got my hs60 today it has 1 dead voice i have located the 80017a chips in it
>under the keyboard,...I have only a voltimeter and a continuity tester as far
>as diagnostic tools go,..
>
>.anyone with half a clue as to how i would go about determining witch of
these
>odd chips (80017a vca/vcf) is a dud <>?? 


There is a way to do this. You put the ju106 ( and hs60 i guess ) Into a
test mode by holding down some switches when you power up. I'm sorry but I
can't remember which ones they are. Maybe you'll find it on the archives.
This will then display the voice being played on the LED display. Just hit
a single key until you get a dead note and the number is the voice that's
dead. Sorry about the lack of information.

***** Hang on, I just did some experimenting and this seems to work:

with power off, hold down key transpose ad midi channel, Turn power on, now
press poly 1 and 2 simultaneously. Now each time you press a key the number
in the display should increment. Hopefully this is the same for the HS 60.

I hope this helps.

Stewart Pye





From martin.czech at intermetall.de  Fri Jan 22 08:55:12 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 22 Jan 1999 08:55:12 +0100 (MET)
Subject: noniverting transistor amp
Message-ID: <199901220755.IAA29559@window.intermetall.de>


> 
> I need to take a digital signal (5v) and convert it to 12v..
> Is this possible to do with 1 transistor amp and maintain phase
> relations/non-inverting?
> 
> It *seems* like every amp I see is inverting.. 
> I guess maybe a darlington configuration would do this, but thats two
> trannies..
> 

Hmm, common emmiter circuits (open collector) can give you any level you
want (Uce max is the limit), but is inverting. An emitter follower is
non inverting, but has gain <=1 , so no larger voltage output. Common
base cicuits may have a too low input impedance.  So: no, there isn't
such a one tranny circuit. You need two common emmiter invertes in series.

I think so, or am I wrong?
m.c.






From stew at uq.net.au  Fri Jan 22 09:00:36 1999
From: stew at uq.net.au (Stewart Pye)
Date: Fri, 22 Jan 1999 19:00:36 +1100
Subject: noniverting transistor amp
In-Reply-To: <36A7B6F7.75ED4329@globaleyes.net>
Message-ID: <199901220906.TAA27565@uq.net.au>

Hi,

Why not use a comparator. Single supply op amp 15V with, say 4V on the
inverting input, and connect your 5V signal to the non inverting input.
This should give about 13V on the output that could be limited with a zener
to 12V ( or use a voltage divider ), Is it for a roland gate trigger?? if
so it should handle 13V no problem. Op Amps are cheap and easy for this
kind of thing. ( IMO )


At 17:23 21/01/99 -0600, Rob wrote:
>
>I need to take a digital signal (5v) and convert it to 12v..
>Is this possible to do with 1 transistor amp and maintain phase
>relations/non-inverting?
>
>It *seems* like every amp I see is inverting.. 
>I guess maybe a darlington configuration would do this, but thats two
>trannies..
>
>
>Rob
> 




From beszedes at cc.u-szeged.hu  Fri Jan 22 09:26:40 1999
From: beszedes at cc.u-szeged.hu (Beszedes Arpad)
Date: Fri, 22 Jan 1999 09:26:40 +0100
Subject: gnuplot ! FOR WINDOWS!!!!
References: <c=GB%a=_%p=BT%l=ATLAS-990121164605Z-5368@mussel.futures.bt.co.uk>
Message-ID: <36A83640.C25C1027@cc.u-szeged.hu>

Hello all!

I have been curious, so I downloaded this GNUPlot software. A understand
that it can draw various diagrams, but I wonder how do you folks at
synth-diy really use this software?
Could somebody explain what is the real use of it in electric design?

Regards,  Arpad.


Dave Burraston wrote:
> 
> Martin and list,
> 
> I had a windows copy of gnuplot that I had desperately been trying to
> locate the binary for on the web. Today I found it :
> 
> http://www.geocities.com/SiliconValley/Foothills/6647/
> 
> Get the windows version, this has menus....  cool....
> 
> Also there is a gnuplot newsgroup comp.graphics.apps.gnuplot
> 
> Enjoy!
> 
> Cheers,
> Dave B
> AKA : jupiter4 at bt-sys.bt.co.uk

-- 
***********************************************
*  Arpad Beszedes                             *
*                                             *
*  Research Group on Artificial Intelligence  *
*  Hungarian Academy of Sciences              *
*  Attila Jozsef University, Szeged, Hungary  *
*  e-mail: beszedes at cc.u-szeged.hu            *
*  tel.: (+36) 62/45-41-45                    *
***********************************************



From THEKn0TiS at aol.com  Fri Jan 22 09:44:34 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Fri, 22 Jan 1999 03:44:34 EST
Subject: tr606 trouble
Message-ID: <78b6390.36a83a72@aol.com>

when in pattern play mode (actually all modes when i get it past the 4th
pattern in the first pattern group it speeds up considerably can any one help
me out it just started today



From jorgen.bergfors at idg.se  Fri Jan 22 10:06:36 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Fri, 22 Jan 1999 10:06:36 +0100
Subject: noniverting transistor amp
Message-ID: <TFSPHZVD@idg.se>

>> > I need to take a digital signal (5v) and convert it to 12v..
>> Is this possible to do with 1 transistor amp and maintain phase
>> relations/non-inverting?
>> > It *seems* like every amp I see is inverting.. > I guess maybe a darlington configuration would do this, but thats two
>> trannies..
>> 

>Hmm, common emmiter circuits (open collector) can give you any level you
>want (Uce max is the limit), but is inverting. An emitter follower is
>non inverting, but has gain <=1 , so no larger voltage output. Common
><<base cicuits may have a too low input impedance.  So: no, there isn't
>such a one tranny circuit. You need two common emmiter invertes in series.

>I think so, or am I wrong?
>m.c.

If you take a P-channel FET with the source tied to ground and the drain tied to +12V via a resistor and take out the signal at the drain. Wouldn't  that work?

/Jorgen





From martin.czech at intermetall.de  Fri Jan 22 10:07:06 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 22 Jan 1999 10:07:06 +0100 (MET)
Subject: gnuplot ! FOR WINDOWS!!!!
Message-ID: <199901220907.KAA29780@window.intermetall.de>

> Hello all!
> 
> I have been curious, so I downloaded this GNUPlot software. A understand
> that it can draw various diagrams, but I wonder how do you folks at
> synth-diy really use this software?
> Could somebody explain what is the real use of it in electric design?
> 
I can explain how I use it.

Sometimes you measure current or voltage depending on another parameter,
like voltage etc. With gnuplot you can convert this table of values
into a graph, this gives some information, I think.

Example: vco frequency / control voltage.

gnuplot can also plot virtually all mathem. functions.
Sometimes I have a circuit idea, solve the equations, and then
I try to figure out what happens. gnuplot gives me a graph
of the functions, I can vary parameters and see the effect.

For me it is a very quick way to avoid conceptual errors.
No need to solder something that wont even work in theory.

So gnuplot saves me a lot of time.

m.c.




From martin.czech at intermetall.de  Fri Jan 22 10:18:31 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 22 Jan 1999 10:18:31 +0100 (MET)
Subject: noniverting transistor amp
Message-ID: <199901220918.KAA29805@window.intermetall.de>

> If you take a P-channel FET with the source tied to ground and the drain tied to +12V via a resistor and take out the signal at the drain. Wouldn't  that work?
> 
Maybe. Depending on threshold voltage, you will not get down to ground.
Same with pnp emitter follower. MOst applications require pretty low
voltage for a "0". High level is not so important.

A dual npn inverter can also be wired as Schmidt-Trigger.
Gives clean transitions.

A LF311 comparator with open collector is the best choice,
if you have a proper supply.

m.c.




From bduggan at netcom.com  Fri Jan 22 11:28:43 1999
From: bduggan at netcom.com (Brett Duggan)
Date: Fri, 22 Jan 1999 02:28:43 -0800 (PST)
Subject: Any disadvantages in mounting PCB's upside-down?
Message-ID: <Pine.3.89.9901220105.A28374-0100000@netcom9>


Hello fellow DIY'ers:

I have constructed two synth-DIY projects in small aluminum boxes so far. 
I am in pursuit of what I would consider to be the "perfect" construction
design for such a project.  My second attempt was a definite improvement
over the first but still not what I would like it to be.  I am hoping that
my third time will be the charm, so I ask the question in the Subject
line: 

Can any of you please tell me if there are any disadvantages in mounting 
PCB's upside-down?  My initial guess would be some kind of heat buildup.
However, the kind of modules I am dealing with here are not real high 
power consumption devices.  In the case of this one project sitting here 
with me, the tallest component on the PCB is a 470uF 25V electrolytic cap.
Would drilling some holes in the sides of the box for ventilation make 
such a mounting possible, or would this even be necessary?

I got the idea for this from my Sequential Circuits Six-Trak, of which the
PCB is mounted upside-down (though at a slight downward angle), including
the heatsink.  There are no dedicated ventilation holes anywhere on the
panel.  However, all of its analog circuitry is completely
microprocessor-controlled, so maybe that's how it is able to get away with
the upside-down mounting?  Anyway, it's really nice to have easy access to
trimpots while the unit is powered up, and for reseating IC's in their
sockets. 

Sorry to be so wordy with my question, but I'd really appreciate hearing 
from any of you that have knowledgable opinions.

Thank you very much!
Brett D




From Juergen.Haible at nbgm.siemens.de  Fri Jan 22 11:49:33 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 22 Jan 1999 11:49:33 +0100
Subject: AW: Question about an op-amp  (NE5517)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820127DAF7@nbgm336a.nbgm.siemens.de>

	>From the Datasheet It looks as if it was not only a substitute but
really the 
	>same as LM13700/LM13600. (There are even some drawings identical in
both
	>datasheets!)

I'd say it's a 2nd source for the 13700 (not the 13600).

JH.




From Juergen.Haible at nbgm.siemens.de  Fri Jan 22 12:28:42 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 22 Jan 1999 12:28:42 +0100
Subject: AW: gnuplot ! FOR WINDOWS!!!!
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820127DBA8@nbgm336a.nbgm.siemens.de>

	>For me it is a very quick way to avoid conceptual errors.
	>No need to solder something that wont even work in theory.

I have it on my PC, too, but I rarely use it for electronic
circuits. I like working with a circuit simaulator much better.
You can get a free version of PSpice from Microsim.
It's restricted in circuit size and only has a small library,
but otherwise it's perfectly working. 

JH. 




From martin.czech at intermetall.de  Fri Jan 22 12:52:58 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 22 Jan 1999 12:52:58 +0100 (MET)
Subject: AW: gnuplot ! FOR WINDOWS!!!!
Message-ID: <199901221152.MAA00498@window.intermetall.de>

> 	>For me it is a very quick way to avoid conceptual errors.
> 	>No need to solder something that wont even work in theory.
> 
> I have it on my PC, too, but I rarely use it for electronic
> circuits. I like working with a circuit simaulator much better.
> You can get a free version of PSpice from Microsim.
> It's restricted in circuit size and only has a small library,
> but otherwise it's perfectly working. 
> 

I didn't describe it excactly, and I knew this was going to happen.
My fault.

Ok, my response should have been:

Of course I don't use gnuplot as a circuit simulator.  I use it before I
actually think about the implementation.  Just to verify that the raw
idea, or concept is correct, that math was done correct.  I can toy
with parameters, see the parameter dependence, before going too far
into detail.

If your concept is wrong, there is no need to think about implementations.

Using a circuit simulator means that you allready must have a 1:1
representation of your circuit.
This would be the second step then (which I skip, to be honest).

Third is breadboard (which I do).

m.c.




From jbrookes at bluebear.freeserve.co.uk  Fri Jan 22 13:51:14 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Fri, 22 Jan 1999 12:51:14 -0000
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <001201be4606$06bd7420$01010101@aardvark>

Apologies if this is slightly off-topic but does anybody know how to wire a
balanced to unbalanced cable. I've just bought a compressor with balanced
XLRs and need to patch it into my system which is all 1/4" mono jacks.
Somebody said to bridge pins 1 & 3 together, but I'm not sure if this forms
the Gnd or Signal. I remember seeing some design that included a small (200
ohm?) resistor as well. Any clues?

Thanks.

Jezz.





From Juergen.Haible at nbgm.siemens.de  Fri Jan 22 13:58:31 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 22 Jan 1999 13:58:31 +0100
Subject: AW: AW: gnuplot ! FOR WINDOWS!!!!
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820127DD65@nbgm336a.nbgm.siemens.de>

	> ... I knew this was going to happen.

I knew there would be some response like this (;->)

	>Of course I don't use gnuplot as a circuit simulator.  I use it
before I
	>actually think about the implementation.  Just to verify that the
raw
	>idea, or concept is correct, that math was done correct.  I can toy
	>with parameters, see the parameter dependence, before going too far
	>into detail.
	>
	>If your concept is wrong, there is no need to think about
implementations.
	>
	>Using a circuit simulator means that you allready must have a 1:1
	>representation of your circuit.

If this would be the case, I would totally agree with you.
But a modern simulator is not like the original Spice anymore.
You have a lot of these basic buiding blocks like exponential
functions, pole / zero definitions, and anything else you can think
of. So I make the rough concept at a completely abstract
level, too. The advantage over a simple tool like gnuplot is that
you can compose your mathematical functions graphically,
with "black boxes" wired together just like a circuit. And you
have much more powerful postprocessing tools, parameter
sweeps and so on.

When your basic concept (not a single electronic component yet !)
works, you can start to exchange certain blocks with schematics
of real circuits. And simulate the abstract parts and the circuit
parts together in one go. 

On a commercial version of PSpice (or IS-Spice, or similar simulators),
you can go on to simulate the whole circuit with electronic components
as a last step - on the free demo versions you cannot do that normally
because of limited size of the circuit. But that is not such a bad thing.
I don't trust a Spice simulation completely, anyway - done it too long
not to know the limitations.

So it is exactly this concept level where I see the main application
for a free demo version circuit simulator. This, and one step beyond,
like using a 2N2222 instead of the transistor of my choice. When
I want to change to a BC550, that's where the demo version says "no".
Fair enough, that's the point where I stop trusting the simulator anyway,
and where it's good to go to breadboard.

I think everybody has develloped his personal favorite way to work.
I just wanted to point out that the free PSpice version can do this
concept level stuff, too, and that I personally like it much better than
Gnuplot.

(I'm using Gnuplot as post processor for in-house programs that
need an easy and standardized data format, btw.)

JH.




From Colin.Fraser at scottishpower.plc.uk  Fri Jan 22 15:28:23 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 22 Jan 1999 14:28:23 -0000
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2CB@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Jezz Brookes [mailto:jbrookes at bluebear.freeserve.co.uk]
> Sent: 22 January 1999 12:51
> To: Synth DIY
> Subject: Slightly OT - balanced to unbalanced cables?
> 
> 
> Apologies if this is slightly off-topic but does anybody know 
> how to wire a
> balanced to unbalanced cable. I've just bought a compressor 
> with balanced
> XLRs and need to patch it into my system which is all 1/4" mono jacks.
> Somebody said to bridge pins 1 & 3 together, but I'm not sure 
> if this forms
> the Gnd or Signal. I remember seeing some design that 
> included a small (200
> ohm?) resistor as well. Any clues?

XLR connections are: pin 1 - shield, pin 2 - hot, or positive signal, pin 3
- cold, or negative signal.
Wiring pin 1 & 3 together wil give you gnd (by fixing the -ve signal at
earth), and pin 2 will be the signal, but (IIRC) you will end up with twice
the signal level at pin 2 and may overdrive input stages.
The 200ohm resistor is possibly used to prevent any ground loops when the
signal is referenced to the shield.

Have you considered adding balanced i/o to your other gear ?
I did this on my modular (with SSM balanced line driver ICs, but there are
cheaper ways), after I bought a Yamaha desk with balanced inputs on every
channel, and it makes a noticeable difference.

My favourite thing about XLRs is that inputs are female, and outputs are
male, so you can extend any cable directly with another cable.
Also, I have a Behringer Multicom compressor with balanced I/O that I can
patch in to any channel on my desk at the input, just by taking the male XLR
from the instrument cable out of the desk input and connecting it to the
female input cable to the compressor, then plugging the male output cable
from the compressor back into the female desk input - saves the cost of a
balanced patchbay.

XLRs are so nice and chunky too, much cooler than scrawny quarter inch
jacks...

Colin f




From b.layer at vikingelectronics.com  Fri Jan 22 15:52:11 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 22 Jan 1999 08:52:11 -0600
Subject: noniverting transistor amp
In-Reply-To: <199901220755.IAA29559@window.intermetall.de>
Message-ID: <3.0.6.32.19990122085211.007d7860@192.168.210.18>

Hi Rob, Martin, all,
 
>> I need to take a digital signal (5v) and convert it to 12v..
>> Is this possible to do with 1 transistor amp and maintain phase
>> relations/non-inverting?
>> 
>> It *seems* like every amp I see is inverting.. 
>> I guess maybe a darlington configuration would do this, but thats two
>> trannies..
>> 
>
>Hmm, common emmiter circuits (open collector) can give you any level you
>want (Uce max is the limit), but is inverting. An emitter follower is
>non inverting, but has gain <=1 , so no larger voltage output. Common
>base cicuits may have a too low input impedance.  So: no, there isn't
>such a one tranny circuit. You need two common emmiter invertes in series.
>
>I think so, or am I wrong?

Nope, you're right. 

If you want gain, you must invert. Emitter followeres (or cathode folowers,
as i call them) have a much lower output impedance, but gain is always <=1.


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

NOTE: When replying, remove the word 
"chaff." from my email address. No spam!



From b.layer at vikingelectronics.com  Fri Jan 22 15:59:30 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 22 Jan 1999 08:59:30 -0600
Subject: Slightly OT - balanced to unbalanced cables?
In-Reply-To: <001201be4606$06bd7420$01010101@aardvark>
Message-ID: <3.0.6.32.19990122085930.007da5a0@192.168.210.18>

Hi Jezz,

>Apologies if this is slightly off-topic but does anybody know how to wire a
>balanced to unbalanced cable. I've just bought a compressor with balanced
>XLRs and need to patch it into my system which is all 1/4" mono jacks.
>Somebody said to bridge pins 1 & 3 together, but I'm not sure if this forms
>the Gnd or Signal. I remember seeing some design that included a small (200
>ohm?) resistor as well. Any clues?

well, you should really use a matching transformer ("balun") or an active
bal-to-SE converter to take advantage of the balanced line capability of
the compressor. if the run from the compressor to the system is _very_
short, you can short pin 1 to 3, which forms the ground with 2 being the
non-inverted signal. I have heard of small resistors (100-200ohms) used to
tie 1 to 3, and this may have some noise advantages.

FYI, XLR pin 1 = ground, sometimes tied to the sheild (same as 1/4" ring).
2= non-inverted (same as 1/4" tip), 3=inverted.

>Thanks.
>
>Jezz.
>
>
>
Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

NOTE: When replying, remove the word 
"chaff." from my email address. No spam!



From cyborg0 at GlobalEyes.net  Fri Jan 22 16:24:25 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 22 Jan 1999 09:24:25 -0600
Subject: noniverting transistor amp
References: <199901220906.TAA27565@uq.net.au>
Message-ID: <36A89829.B5C8E983@globaleyes.net>

Stewart Pye wrote:
> 
> Hi,
> 
> Why not use a comparator. Single supply op amp 15V with, say 4V on the
> inverting input, and connect your 5V signal to the non inverting input.
> This should give about 13V on the output that could be limited with a zener
> to 12V ( or use a voltage divider ), Is it for a roland gate trigger?? if
> so it should handle 13V no problem. Op Amps are cheap and easy for this
> kind of thing. ( IMO )
> 
> At 17:23 21/01/99 -0600, Rob wrote:
> >
> >I need to take a digital signal (5v) and convert it to 12v..
> >Is this possible to do with 1 transistor amp and maintain phase
> >relations/non-inverting?
> >
> >It *seems* like every amp I see is inverting..
> >I guess maybe a darlington configuration would do this, but thats two
> >trannies..
> >
> >
> >Rob
> >

WEll, its for a tb303, so that means I have +12v, +5.333v (which is very
touchy), and ground..
so, I guess I could hook up a TL-082 as a comparator, but those take up
a lot of pcb real estate, and I will have to do the voltage divider
thing to get it to work on a single sided supply..
rob



From cyborg0 at GlobalEyes.net  Fri Jan 22 16:33:10 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 22 Jan 1999 09:33:10 -0600
Subject: noniverting transistor amp
References: <TFSPHZVD@idg.se>
Message-ID: <36A89A36.3C11A22B@globaleyes.net>

jorgen.bergfors at idg.se wrote:

> >Hmm, common emmiter circuits (open collector) can give you any level you
> >want (Uce max is the limit), but is inverting. An emitter follower is
> >non inverting, but has gain <=1 , so no larger voltage output. Common
> ><<base cicuits may have a too low input impedance.  So: no, there isn't
> >such a one tranny circuit. You need two common emmiter invertes in series.
> 
> >I think so, or am I wrong?
> >m.c.
> 
> If you take a P-channel FET with the source tied to ground and the drain tied to +12V via a resistor and take out the signal at the drain. Wouldn't  that work?

Yeah, but P-channel FETs are not that common, and I want to build this
with stuff that is common..

 I guess if anything this thread has been sort of a challenge...With
unlimited resources, one could design anything.. But, when u limit the
resources and available materials, it gets very tricky.

AFAIK, it seems requires two trannies.. But, I thought that perhaps
there was a way to do this..

I guess the opamp is the way to go..

Rob



From Colin.Fraser at scottishpower.plc.uk  Fri Jan 22 16:59:31 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 22 Jan 1999 15:59:31 -0000
Subject: noniverting transistor amp
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2CC@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Rob [mailto:cyborg0 at GlobalEyes.net]
> Sent: 22 January 1999 15:24
> To: Stewart Pye
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: noniverting transistor amp
> 
> 
> WEll, its for a tb303, so that means I have +12v, +5.333v 
> (which is very
> touchy), and ground..
> so, I guess I could hook up a TL-082 as a comparator, but 
> those take up
> a lot of pcb real estate, and I will have to do the voltage divider
> thing to get it to work on a single sided supply..

Is it for a mod to a real 303 or are you building a clone ?

I'm pretty sure there are some spare gates in the real 303 that will allow
you to invert the signal, and then use a single transistor for the level
shift.


Colin f



From kjetilod at stud.ntnu.no  Fri Jan 22 17:01:37 1999
From: kjetilod at stud.ntnu.no (Kjetil Ødegaard)
Date: 22 Jan 1999 17:01:37 +0100
Subject: tr606 trouble
In-Reply-To: THEKn0TiS@aol.com's message of "Fri, 22 Jan 1999 03:44:34 EST"
References: <78b6390.36a83a72@aol.com>
Message-ID: <jevzp7b70v2.fsf@apollo.orakel.ntnu.no>

* THEKn0TiS at aol.com
|
| when in pattern play mode (actually all modes when i get it past the 4th
| pattern in the first pattern group it speeds up considerably can any one help
| me out it just started today

In addition to controlling the tempo using the `Tempo' button, the
TR-606 has four different `time modes' (or `speed modes', if you
like); this is to make it easy to switch between double and half-time
grooves, I guess. The lever marked `scale' above the 16 small buttons
controls this, but any adjustment you make doesn't have any effect
untill you press the `Function' key (or maybe you have to press and
hold it... I don't really remember).

So if you enter Pattern Write mode, find the pattern that's causing
you trouble, toy around with the `scale' lever and the `Function' key,
you should be alright, methinks.
-- 
"Danger, Will Robinson!"
  Kjetil ?degaard  -  {kjetilod at stud.ntnu.no}



From Colin.Fraser at scottishpower.plc.uk  Fri Jan 22 17:09:35 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 22 Jan 1999 16:09:35 -0000
Subject: Front Panels
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2CD@catsprntp01.cat.scottishpower.plc.uk>

Has anyone tried anything similar to the front panel anodising system shown
at? http://www.megaelect.demon.co.uk/gedakop.html
<http://www.megaelect.demon.co.uk/gedakop.html>  ?
It's basically a pre-sensitised aluminium sheet that you expose artwork on
with a UV box (same as for a PCB), dye it, and seal in the dye in hot water.
If anyone has used this or similar, I'd be interested to hear how it went.
?
If the price if right it could be a very nice way of producing front panels.
?
Colin f
?



From cyborg0 at GlobalEyes.net  Fri Jan 22 17:41:28 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 22 Jan 1999 10:41:28 -0600
Subject: noniverting transistor amp
References: <BA865FF10473D211BC6F00805F0D830702D2CC@catsprntp01.cat.scottishpower.plc.uk>
Message-ID: <36A8AA38.BC4966BE@globaleyes.net>

"Fraser, Colin J" wrote:
> 
> > -----Original Message-----
> > From: Rob [mailto:cyborg0 at GlobalEyes.net]
> > Sent: 22 January 1999 15:24
> > To: Stewart Pye
> > Cc: synth-diy at mailhost.bpa.nl
> > Subject: Re: noniverting transistor amp
> >
> >
> > WEll, its for a tb303, so that means I have +12v, +5.333v
> > (which is very
> > touchy), and ground..
> > so, I guess I could hook up a TL-082 as a comparator, but
> > those take up
> > a lot of pcb real estate, and I will have to do the voltage divider
> > thing to get it to work on a single sided supply..
> 
> Is it for a mod to a real 303 or are you building a clone ?
> 
> I'm pretty sure there are some spare gates in the real 303 that will allow
> you to invert the signal, and then use a single transistor for the level
> shift.
> 
> Colin f

Hey.. yep.. thats an idea.. Now, I just gotta find a few 5v gates that
are running some inputs to ground and cut the traces..
actually, the unit Im modding is a clone (FR777) and, since I am trying
to run my design off of the least important power source (12V), I need
to boost the accent and glide to a level that will allow them to trigger
12v logic.
Rob



From jbrookes at bluebear.freeserve.co.uk  Fri Jan 22 17:46:31 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Fri, 22 Jan 1999 16:46:31 -0000
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <000201be4626$e12b85a0$01010101@aardvark>

>> Apologies if this is slightly off-topic but does anybody know
>> how to wire a
>> balanced to unbalanced cable.

>XLR connections are: pin 1 - shield, pin 2 - hot, or positive signal, pin 3
>- cold, or negative signal.


<snip>

Thanks for the info. I can now try out my Trident compressor (the same
people who make the nice big mixing desks) - a bargain for 40ukp.

>Have you considered adding balanced i/o to your other gear ?
>I did this on my modular (with SSM balanced line driver ICs, but there are
>cheaper ways), after I bought a Yamaha desk with balanced inputs on every
>channel, and it makes a noticeable difference.

>
>My favourite thing about XLRs is that inputs are female, and outputs are
>male, so you can extend any cable directly with another cable.
>Also, I have a Behringer Multicom compressor with balanced I/O that I can
>patch in to any channel on my desk at the input, just by taking the male
XLR
>from the instrument cable out of the desk input and connecting it to the
>female input cable to the compressor, then plugging the male output cable
>from the compressor back into the female desk input - saves the cost of a
>balanced patchbay.


I would like to but it would mean a lot of work at the moment as nothing
else is balanced and I've just spent 50ukp on a load of 1/4" mono Neutrik
jacks. It would mean rebuilding my patchbay, boxes on the output of every
synth (plus the problem of power supplies to each box!). If I was starting
from scrtach I might do it.

>XLRs are so nice and chunky too, much cooler than scrawny quarter inch
>jacks...


I agree there! I had enough black anodised Neutrik XLRs to make up the
balanced-unbalanced and vice versa cables and they do look cool, especially
in black.

And now a question - anyone have a circuit for an opto compressor? There was
a simple one last year in The Mix (it must have been simple to appear in
that mag). I'm after one for an effect more than transparency. I want to
build one for a mate who's trying to record drums to minidisk...





From clark at andrews.edu  Fri Jan 22 18:19:09 1999
From: clark at andrews.edu (Tony Clark)
Date: Fri, 22 Jan 1999 12:19:09 -0500 (EST)
Subject: Any disadvantages in mounting PCB's upside-down?
In-Reply-To: <Pine.3.89.9901220105.A28374-0100000@netcom9>
Message-ID: <Pine.SOL.3.91.990122121736.7290A-100000@edmund.cs.andrews.edu>

> Can any of you please tell me if there are any disadvantages in mounting 
> PCB's upside-down?  My initial guess would be some kind of heat buildup.
> However, the kind of modules I am dealing with here are not real high 
> power consumption devices.  In the case of this one project sitting here 
> with me, the tallest component on the PCB is a 470uF 25V electrolytic cap.
> Would drilling some holes in the sides of the box for ventilation make 
> such a mounting possible, or would this even be necessary?

   The only drawback to having circuits upside-down is if you socket 
IC's.  Chip creep is bad enough with circuit boards right-side up!  So 
I'd suggest soldering everything down really well and you should be 
fine!

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From Juergen.Haible at nbgm.siemens.de  Fri Jan 22 18:22:11 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 22 Jan 1999 18:22:11 +0100
Subject: AW: noniverting transistor amp
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820129BB69@nbgm336a.nbgm.siemens.de>

	>Yeah, but P-channel FETs are not that common

... and they don't perform miracles either.

JH.



From Chris.List at sc.siemens.com  Fri Jan 22 18:55:45 1999
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Fri, 22 Jan 1999 12:55:45 -0500
Subject: Front Panels
Message-ID: <81A062BC5305D111A9D700805F06596801836C89@maildepo.sc.siemens.com>

This looks similar to Metalphoto, see; http://www.metalphoto.com

I think they were "the originals".

- That's how I did the ASM-1 faceplates that I sold (before anyone asks, no,
I don't have anymore!)

I didn't do them myself as I don't have access to a UV vacuum table, I had
it done by the actual Metalphoto plant (though there are sign-makers and
whatnot around the country who do it at well...

The results are absolutely the best quality, most indestructible faceplate
markings I've ever seen (beats the crap out of silk-screening for
durability). I wouldn't do it myself because of all the fancy equipment
needed to do it right.

- CList


> -----Original Message-----
> From:	Fraser, Colin J [SMTP:Colin.Fraser at scottishpower.plc.uk]
> Sent:	Friday, January 22, 1999 11:10 AM
> To:	'synth-diy at mailhost.bpa.nl'
> Subject:	Front Panels
> 
> Has anyone tried anything similar to the front panel anodising system
> shown
> at? http://www.megaelect.demon.co.uk/gedakop.html
> <http://www.megaelect.demon.co.uk/gedakop.html>  ?
> It's basically a pre-sensitised aluminium sheet that you expose artwork on
> with a UV box (same as for a PCB), dye it, and seal in the dye in hot
> water.
> If anyone has used this or similar, I'd be interested to hear how it went.
> ?
> If the price if right it could be a very nice way of producing front
> panels.
> ?
> Colin f
> ?



From oakley at techrepairs.freeserve.co.uk  Fri Jan 22 20:13:36 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Fri, 22 Jan 1999 19:13:36 -0000
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <006501be463e$0d7a7b40$3526883e@default>

Hi,

Try the Rane website. There is lots of good ideas on the site, including
a bit on wiring balanced systems. http://bsd.rane.com/ HTML and pdf
files available.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From oakley at techrepairs.freeserve.co.uk  Fri Jan 22 20:21:00 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Fri, 22 Jan 1999 19:21:00 -0000
Subject: New panel arrived
Message-ID: <006601be463e$0e5c4fc0$3526883e@default>

Hi,

Today a rather heavy flat parcel arrived at my house. It was a panel
from Schaeffer-Apparatebau for my poly. Bloody fantastic. Very good and
very cheap. Thanks to Juergen for the tip. They will do 3mm panels,
contrary to what they say on the site.

BUT... here's the catch. I don't speak German. So when I sent them the
design file with my front panel on, I said I only wanted a quote. The
quote came back and it was cheap for the panel, about 60UKP. I then
thanked them for the quote and said I would order one in a few weeks
when I had some spare cash. But two weeks later, I got the panel through
the post. Whoops. I suppose I better pay for it now. It does look very
nice though.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From guidogoe at xs4all.nl  Fri Jan 22 21:51:08 1999
From: guidogoe at xs4all.nl (Guido Goebertus)
Date: Fri, 22 Jan 1999 20:51:08 GMT
Subject: LM13600 multimode filter!
References: <36A7F45B.752E@swipnet.se>
Message-ID: <917036852-193428AEicMi@xs4all.nl>

>OSCar multimode filter with a LM13600/13700 at:
>http://home8.swipnet.se/~w-88660/schpcb.htm

>Just wanted to mention it!

>Agusto Pinochet

I see.
You like your Chili real hot, don't you?

Just couldn't ressist....

Guido...




From magnus at analogue.org  Sat Jan 23 00:12:26 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 23 Jan 1999 00:12:26 +0100
Subject: Some JFET thoughts...
Message-ID: <199901222312.AAA19173@mail2.it.kth.se>

Hi!

I have been thinking a bit about these JFETs that we tend to use...

First, there are 2N4391's (used in the ASM-1) available from
Temic/Siliconix (http://www.temic.com/ and http://www.siliconix.com/).
I would not be supprised if others makes them aswell, there are three
diffrent packages (including SOT-23) available.

There is also a number of possible improvements over the 2N4391, if
you are willing to trade switch speed for lower resistance and thus
have shorter reset time of the oscillator.

Without much deeper thoughts, I picked out the J105 which has an
rDS(on) of maximum 3 ohm as compared to the 30 ohm of the 2N4391.
There are several other picks that could be interesting for this, but
giving a quick look the the above webpages makes me pick J105.

Also, take a peek at the VCR7N, it could be a interesting thing for
people doing variable resistance stuff with FETs.

Cheers,
Magnus



From jlarryh at iquest.net  Sat Jan 23 01:40:10 1999
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Fri, 22 Jan 1999 18:40:10 -0600
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <199901222333.AAA16446@mailhost.bpa.nl>

Does the compressor have ONLY balanced XLR "ins" and "outs"?   If so, I
would consider matching transformers for the task so that the impedances
match.  I have had not problem at all with the ones sold at Radio Shack. 
last time I checked you can get them for about $15 each.  They come in both
 Male - Female gender chages so you don't have to make any special
connectors.

On the subject of system interconnection and the avoidance of ground loops
and other problems, I found an absolutely wonderful souce of good
information with drawings and LOTs of detail.
Check out the technical notes in the library at www.rane.com/

Larry Hendry

----------
> From: Jezz Brookes <jbrookes at bluebear.freeserve.co.uk>
> To: Synth DIY <synth-diy at mailhost.bpa.nl>
> Subject: Slightly OT - balanced to unbalanced cables?
> Date: Friday, January 22, 1999 6:51 AM
> 
> Apologies if this is slightly off-topic but does anybody know how to wire
a
> balanced to unbalanced cable. I've just bought a compressor with balanced
> XLRs and need to patch it into my system which is all 1/4" mono jacks.
> Somebody said to bridge pins 1 & 3 together, but I'm not sure if this
forms
> the Gnd or Signal. I remember seeing some design that included a small
(200
> ohm?) resistor as well. Any clues?
> 
> Thanks.
> 
> Jezz.
> 
> 



From ijfritz at earthlink.net  Sat Jan 23 04:03:53 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Fri, 22 Jan 1999 20:03:53 -0700
Subject: J105
References: <199901222312.AAA19173@mail2.it.kth.se>
Message-ID: <36A93C19.773E935A@earthlink.net>

Magnus --

An interesting looking device, indeed. I haven't been able to find these
in small quantities, though. Do you have a source? It would be very
interesting to see what kind of performance you could get. One other
point: the input capacitance is about 10x that of the 2N4391.  As Terry
pointed out, this capacitance causes some spiking. I don't think
switching speed is much of an issue as both devices are fast compared to
the time required for discharge.

  Ian

Magnus Danielson wrote:
> 
> 
> There is also a number of possible improvements over the 2N4391, if
> you are willing to trade switch speed for lower resistance and thus
> have shorter reset time of the oscillator.
> 
> Without much deeper thoughts, I picked out the J105 which has an
> rDS(on) of maximum 3 ohm as compared to the 30 ohm of the 2N4391.



From aschrock at cs.brandeis.edu  Sat Jan 23 06:55:28 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 23 Jan 1999 00:55:28 -0500 (EST)
Subject: Digest?
In-Reply-To: <MAPI.Id.0016.00637020202020203030303330303033@MAPI.to.RFC822>
Message-ID: <Pine.SGI.3.95.990123005151.24078A-100000@opal.cs.brandeis.edu>

On Tue, 19 Jan 1999, Hans Pelleboer wrote:
> Synth-DiY is evidently getting around --
> |I receive some fifty messages a day
> on average -- and the number seems to be increasing.
> 
> As this is the case, I was wondering if it would be a good idea
> to issue the letters related to this group in a digested version --
> less hogging of mail space and definitely a less 
> cluttered mailbox!
> 
> The digest could be sent on a dialy basis or whenever the
> number of messages exceeds a certain number; say,
> fifty or so --a simple script should take care of that
> 
> What would you think?

Frankly, I think 50 messages a day is an exaggeration, I've rarely seen
that kind of traffic. Considering that AH really does get over 100 a day
(110 just today), the traffic here is relatively low-traffic and
noise-free. There are no forsale posts, no "what's a VCF?" posts, and
nothing that could be considered flaming. Come to think of it, why am I
even on AH.. 

Andrew

-| Andrew Schrock | aschrock at cs.brandeis.edu |-







From aschrock at cs.brandeis.edu  Sat Jan 23 10:15:21 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sat, 23 Jan 1999 04:15:21 -0500 (EST)
Subject: New panel arrived
In-Reply-To: <006601be463e$0e5c4fc0$3526883e@default>
Message-ID: <Pine.SGI.3.95.990122170650.23097A-100000@opal.cs.brandeis.edu>

On Fri, 22 Jan 1999, Tony Allgood wrote:
> Today a rather heavy flat parcel arrived at my house. It was a panel
> from Schaeffer-Apparatebau for my poly. Bloody fantastic. Very good and
> very cheap. Thanks to Juergen for the tip. They will do 3mm panels,
> contrary to what they say on the site.
> 
> BUT... here's the catch. I don't speak German. So when I sent them the
> design file with my front panel on, I said I only wanted a quote. The
> quote came back and it was cheap for the panel, about 60UKP. I then
> thanked them for the quote and said I would order one in a few weeks
> when I had some spare cash. But two weeks later, I got the panel through
> the post. Whoops. I suppose I better pay for it now. It does look very
> nice though.

Yeah, they'll do that.. possibly a bit too trusting? The panels do look
great, IMO, altho it does take 3 weeks to get to the US. They do take
mastercard now, which saves us yanks from awful costs and hassle. 

They are supposedly updating the software to allow for the 3mm option, but
for now if you just let them know via email that will do the trick.  There
is an email address for a person who speaks english quite fluently. I
deleted a lot of old email so I don't have it on-hand, but if the main
email address doesn't get you a reply, let me know, I'll try to get the
exact email for ya. I believe Kai Shaeffer himself is the gent I spoke to
this summer, and he was quite fluent over email. 

I think they're a great company, and are doing quite a good job of
drumming up buisness! 

Andrew
Debating getting his Tony Allgood VCF-1 module's front panel done by
Schaeffer-Apparatebau.. mmm... almost too good, I'd be afraid to mark it
up... 

-| Andrew Schrock | aschrock at cs.brandeis.edu |-





From macnutt at westel.net  Sat Jan 23 15:05:14 1999
From: macnutt at westel.net (Phil Macnutt)
Date: Sat, 23 Jan 1999 08:05:14 -0600
Subject: Digest?
References: <Pine.SGI.3.95.990123005151.24078A-100000@opal.cs.brandeis.edu>
Message-ID: <36A9D719.940706CD@westel.net>

I am new to both diy and to AH, and I have to agree with Andrew.  I was
subscribed to AH, but had to stop because I was spending my entire day
deleting messages.  I think AH is great, I just can't handle the bandwidth.
So far, I find the diy messages interesting and managable.

I sure hope that diy stays low-noise.  Sometimes less is better...

p.s.  Regarding the thread on front panels, I have trying to think of a way
to produce nice panels myself.  I have worked with anodizing shops before,
and I have found them to be very expensive, and not geared toward small
orders.

Has anyone had success working with these type shops?


Andrew Schrock wrote:

> On Tue, 19 Jan 1999, Hans Pelleboer wrote:
> > Synth-DiY is evidently getting around --
> > |I receive some fifty messages a day
> > on average -- and the number seems to be increasing.
> >
> > As this is the case, I was wondering if it would be a good idea
> > to issue the letters related to this group in a digested version --
> > less hogging of mail space and definitely a less
> > cluttered mailbox!
> >
> > The digest could be sent on a dialy basis or whenever the
> > number of messages exceeds a certain number; say,
> > fifty or so --a simple script should take care of that
> >
> > What would you think?
>
> Frankly, I think 50 messages a day is an exaggeration, I've rarely seen
> that kind of traffic. Considering that AH really does get over 100 a day
> (110 just today), the traffic here is relatively low-traffic and
> noise-free. There are no forsale posts, no "what's a VCF?" posts, and
> nothing that could be considered flaming. Come to think of it, why am I
> even on AH..
>
> Andrew
>
> -| Andrew Schrock | aschrock at cs.brandeis.edu |-




From brun at bart.nl  Sat Jan 23 16:52:22 1999
From: brun at bart.nl (Jeroen Bruintjes)
Date: Sat, 23 Jan 1999 16:52:22 +0100
Subject: Update webpage
Message-ID: <199901231552.QAA22414@Njord.bart.nl>

I've updated my webpage on http://www.bart.nl/~brun/index.htm

- The pricelist is new (may only be of interest to Dutch readers)
- I added a link to http://bermuda.ucd.ie/bridge/cs80.html, an 
impressive page that has most of the CS 80-schematics scanned!

Thanks and bye,

Jeroen




--> Brun, met een dakje op de u.

Nu ook op http://www.bart.nl/~brun/index.htm



From maf at mcs.net  Sat Jan 23 17:41:38 1999
From: maf at mcs.net (Michael A. Firman)
Date: Sat, 23 Jan 1999 10:41:38 -0600 (CST)
Subject: MEME performance in Chicago
Message-ID: <199901231641.KAA22010@Mercury.mcs.net>

Hi all,

I know Andre' Stordeur posted a message a few days
ago about this, but I thought that I'd drop a little
reminder:

The Midwest Electronic Music Ensemble will be giving
a performance tonight (January 23rd) at 7:30 at the 
Logan Beach Cafe, 2537 North Kedzie in Chicago Illinois.

All you DIYers in Chicagoland come on out and check us
out. The place is small (and we are large - there are
six of us) so get there early.

There should be some interesting music and out of the
ordinary equipment (Serge, Buchla, Wiard, etc.).
Grant Richter and Andre' Stordeur (amongst others) will
be there both probably sporting some DIY musical gear.

See you there.
------------------------------------------------------------
|Michael A. Firman <maf at mcs.net>
|Naperville, IL USA (finger maf at cluster.mcs.net for PGP key)
|http://www.mcs.net/~maf



From edusilva at bahianet.com.br  Sat Jan 23 18:06:00 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 23 Jan 1999 15:06:00 -0200
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <199901231712.PAA14855@postman.bahianet.com.br>

De: Jezz Brookes <jbrookes at bluebear.freeserve.co.uk>

(snip!)
 
> And now a question - anyone have a circuit for an opto compressor? There
was
> a simple one last year in The Mix (it must have been simple to appear in
> that mag). I'm after one for an effect more than transparency. I want to
> build one for a mate who's trying to record drums to minidisk...

Here's a good one:

http://www.synthfool.com/diy/hj_preco.gif

I have the schem of the UREI LA-5 opto-limiter. If you want, I can mail you
a copy. I isn't avaliable on the Net (I think).

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil


 



From gerryd at ntx-tech.com  Sat Jan 23 18:45:18 1999
From: gerryd at ntx-tech.com (Gerry Dahl)
Date: Sat, 23 Jan 1999 11:45:18 -0600
Subject: Invert ADSR
Message-ID: <36AA0AAE.43FB@ntx-tech.com>

Hi Everyone,
I'm looking for a way to invert the ADSR And the A(S)R on my PAIA
Fatman. Any help on this would be great.
Thanks.
Gerry Dahl



From edusilva at bahianet.com.br  Sat Jan 23 20:17:00 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sat, 23 Jan 1999 17:17:00 -0200
Subject: VCR2N/4N JFET VC resistors
Message-ID: <199901231923.RAA11912@postman.bahianet.com.br>

Have anyone in the list ever worked with these components?
I think they can be usefull in VC synth modules.

Datasheet: (only 41 Kb)
http://www.siliconix.com/www/data/smallfet/70293.pdf

Some info from the datasheet:

Features
  Continuous Voltage-Controlled Resistance
  High Off-Isolation
  High Input Impedance

Benefits
  Gain Ranging Capability/Wide Range Signal Attenuation
  No Circuit Interaction
  Simplified Drive

Applications
  Variable Gain Amplifiers
  Voltage Controlled Oscillator
  AGC

Description
   The VCR2N/4N/7N JFET voltage controlled resistors have an ac
drain-source resistance that is controlled by a dc bias voltage (VGS)
applied to their high impedance gate terminal. Minimum rDS occurs when VGS
= 0 V. As VGS approaches the pinch-off voltage, rDS rapidly increases. This
series of junction FETs is intended for applications where the drain-source
voltage is a low-level ac signal with no dc component.


Edu
_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brazil



From uzs159 at uni-bonn.de  Sat Jan 23 22:21:28 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Sat, 23 Jan 1999 22:21:28 +0100
Subject: Discharge Switches (was: Re: J105 )
In-Reply-To: <36A93C19.773E935A@earthlink.net>
References: <199901222312.AAA19173@mail2.it.kth.se>
Message-ID: <3.0.5.32.19990123222128.00901520@ibm.rhrz.uni-bonn.de>

Ian Fritz wrote:
>An interesting looking device, indeed. I haven't been able to find these
>in small quantities, though. Do you have a source? It would be very
>interesting to see what kind of performance you could get. One other
>point: the input capacitance is about 10x that of the 2N4391.  As Terry
>pointed out, this capacitance causes some spiking. I don't think
>switching speed is much of an issue as both devices are fast compared to
>the time required for discharge.

>Magnus Danielson wrote:
>>
>>
>> There is also a number of possible improvements over the 2N4391, if
>> you are willing to trade switch speed for lower resistance and thus
>> have shorter reset time of the oscillator.
>>
>> Without much deeper thoughts, I picked out the J105 which has an
>> rDS(on) of maximum 3 ohm as compared to the 30 ohm of the 2N4391.


Don't overlook the leakage effects on the lower end of the scale.
It would gain nothing if you find a FET with one halve the R(on) and double
the leakage. 

And two more thoughts on the subject of discharge switches:
(...also a very recyclable thread...) 

I found an interesting idea in Horowitz & Hill, they show how to make a
high precision integrator, as switch they use two Fets in series (though
they use MOSFETS).One has the larger portion of the voltage across it, and
the other a very small Vds. The middle of this arrangement is grounded via
a 1M Resistor, so the leakage current of the one with the high voltage
flows to ground. Kind of a guarding technique. Now what I think is this can
be done similarly with JFETS (then we would have essentially only gate
leakage contribution which is 1-10 pA). 
One can use a smaller cap value to bring the speed up at high frequencies.

And the second thing, charge injection from the gate-channel capacitance
can probably eliminated by adding the inverted discharge signal to the signal 
thru a tiny cap. 

Bye
 Rene

             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From will7370 at tao.sou.edu  Sat Jan 23 23:02:42 1999
From: will7370 at tao.sou.edu (Rob & Heather Williams)
Date: Sat, 23 Jan 1999 14:02:42 -0800
Subject: Using Soundblaster 32 as effects device?
Message-ID: <36AA4702.3CCFECC3@tao.sou.edu>

Hi folks,

Has anyone ever used one of the Soundblaster series of
computer soundcards as a cheap effects device for their
synths?  My PC has the Soundblaster 32 card installed.  It
offers flanging, delay, distortion, echo etc for the onboard
synth instruments.  Not sure if an external audio input can
be processed too (the card DOES have one).  Be nice if there
was a utility that put them ALL on the screen at the same
time with adjustable sliders that I could tweek.

I was thinking about running my Odyssey through it to see
what it could do.  Does anybody know of another computer
utility program that can take advantage of my Soundblaster
card and it's external audio input for on-screen manipulated
effects?

Robert



From jhaible at primus-online.de  Sun Jan 24 01:26:09 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 24 Jan 1999 01:26:09 +0100
Subject: Re-inventing (?) the VC envelope ?
Message-ID: <19990124002732.17584.qmail@nuernberg2.pop.metronet.de>

Ladies and Gentlemen,

I 'd like to proudly present a circuit for the VCA core of a voltage
controlled
envelope generator.

The problem is all too well known: You can build a decent voltage
controlled
envelope around an OTA like the 3080, plus the usual control logic for a
normal ADSR circuit. But the offset voltage change of the OTA over its 
control current will result in relative large offset voltage errors at the
ADSR
output. This can be several millivolts, and it will change with different
time constants for attack, decay and release.

This problem was solved in the CEM3310 chip long ago by building a rather 
complicated "composite" 2-quadrant exponential multiplier. (I hope this
describes the idea more or less). I have thought about building a discrete
circuit that uses the Curtis method for a long time, but the complementary 
output opamp and the heap of transistors involved in current mirrors have
frightened me away.

Then Joachim Verghese came up with his brilliant idea of splitting the
exponential
multiplier and the positive / negative direction switching of the VCA into 
separate parts. He presented a circuit with a sign / magnitude full wave
rectifier,
an exponential multiplier, and an OTA that only switches the sign of the
output
current (i.e. doesn't contribute to the offset voltage anymore).

Joachim's circuit is, while pleasantly inexpensive, still a rather large
circuit, and
so I tried to simplify it a little. My idea was to build an expo multiplier
that would
perform the sign / magnitude stuff all by itself, in other words
auto-configure
itself to current source or current sink mode, depending on the input
current 
sign. So I came back to the old Curtis idea, but I ended up with a much
smaller
circuit.

First step: Build two separate expo multipliers, one for source, and one
for sink.
Their linear inputs and outputs could be connected together - they would
not
interfere with each other, because one will be passive when the other
conducts.
This idea was taken from the CEM chip, but I used two npn transistors for
the
sink part, and two pnp chips for the source part, just as one would do with
two separate circuits.

Second step: Use the same opamp for the servo loop around both differential
pairs. Unlike the Curtis method, I don't need complementary outputs. A
normal
opamp will feed both halves alternatively with the right sign of current
flow, with 
a little "dead band" near zero, just like a precision full wave rectifier
circuit.

Third step: Both halves of this composite source / sink exponential
multiplier would
normally need complementary control voltages at the npn / pnp transistor
bases.
One could simply add an inverter here, but then again these are two
transistor
*pairs*, so in order to give them complementary steering from one single
CV, I just
grounded the 1st transistor's base of the npn pair, and the 2nd
transistor's
base of the pnp pair, and connected the CV to the two remaining
transistor's bases.
(It looks like a diagonal connection if you draw it as separate exp
converters.)

Fourth step: Redraw the circuit (;->). Well, not such an important step.
But if you
look at the final version of the schematics, the circuit looks so dead
simple that
I had the biggest doubts whether it would work at all. But no need to worry
-
it actually works. I have built it on the breadboard, and I got time
constants from
milliseconds to the minute range, and no more than 3mV offset. With TL071
opamps and unmatched BC550C and 560C transistors.

I have only tested the core of an envelope generator (a lag circuit like
Joachim's),
but I have no doubt that it will work in a full VC ADSR as well.

I hope that the encouraging results of this little test will keep their
promise in
general applications - any hints about possible problems are welcome.

And finally a question (Paul might be able to answer this) : When I look at
the
CEM3310 from this new point of view I wonder if this simple circuit might
have been what Doug Curtis had in mind as well. Could it be that the idea
is
exactly the same, but all this current mirror stuff in the 3310 was just
because
of the lack of "good" pnp transistors in the bipolar process he used ??

Ok, this was a lot of words for those who are interested in the progress of
finding
this circuit. Here comes the schematic diagram. It's a small file, and from
our recent
discussion I get that it's ok to send this to the synth-diy list directly.
So here it
is:

JH.

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From will7370 at tao.sou.edu  Sun Jan 24 01:26:30 1999
From: will7370 at tao.sou.edu (Rob & Heather Williams)
Date: Sat, 23 Jan 1999 16:26:30 -0800
Subject: Fatman mod to add square wave?
Message-ID: <36AA68B6.ED871005@tao.sou.edu>

Hi folks,

Is there a PAiA Fatman mod out there for taking the sawtooth
output from each oscillator and triggering a simple
squarewave from it?  The resulting squarewave could be
reinserted back into the rest of the Fatman for further
processing.  

Also, what about a circuit that could take the sawtooth
output of each oscillator and smooth over the rough edges
enough to give it a pseudo-sinewave?

Another idea would be a simple white/pink noise source for
wind/ocean/snare drum effects.

I've seen a lot of mods out there for the Fatman, but how
come nothing like these?

Robert



From magnus at amalogue.org  Sun Jan 24 01:47:55 1999
From: magnus at amalogue.org (Magnus Danielson)
Date: Sun, 24 Jan 1999 01:47:55 +0100
Subject: J105
In-Reply-To: Your message of "Fri, 22 Jan 1999 20:03:53 -0700"
References: <36A93C19.773E935A@earthlink.net>
Message-ID: <199901240047.BAA27416@mail2.it.kth.se>

>>>>> "IF" == Ian Fritz <ijfritz at earthlink.net> writes:

 IF> Magnus --
 IF> An interesting looking device, indeed. I haven't been able to find these
 IF> in small quantities, though. Do you have a source?

I currently doesn't have one, but I think that I actually bougth some
many years ago.

I just checked out the Sales contacts for Sweden, and there are
several of them here, so I would just spend peek at the visay pages to
see if any of them fits your need.

Farnell for instance carries the 2N4391 and J108 (similar to the J105,
another possible choice) among several others.

My main point was that there are a number of devices out there that
migth be considered, each having their merits and it could be a
interesting thing to discuss, one might learn something on the way.

 IF> It would be very
 IF> interesting to see what kind of performance you could get. One other
 IF> point: the input capacitance is about 10x that of the 2N4391.  As Terry
 IF> pointed out, this capacitance causes some spiking. I don't think
 IF> switching speed is much of an issue as both devices are fast compared to
 IF> the time required for discharge.

I know for a fact that the LM311 is a real noise-makes when I turn the
FET of in the ASM-1 VCO. I get all kinds of frequencies. I haven't
cured it but it is time to do so, I am considering a 100 nF or so
sitting across the LM311 body. The LM311 is sitting tigth at -15 V
during the capacitor charging, then as the capacitor is near the
comparator voltages of +5V the LM311 output starts to slowly rise up
to 0V. As it comes near 0V the FET starts discharging the capacitor
while the LM311 still strives towards 0V (but now much more slowly),
then when the cap hits the floor the LM311 falls very quickly to -15V,
and by quick I am talking of some 25-50 ns (BTW, I have this on a
oscilloscope picture that I appended, but I didn't zoom in on the
falltime for more accurate reading). At this time the negative power
line becomes very noisy and you see several strong frequencies pop out
of the box, giving a peak-to-peak distrurbance of 2.4V on raw
sawsignal. A 2.9 MHz signal is to be found as well as a strong 5.3 MHz
signal.

So, in true EMC spirit there is several ways to attack the problem,
one is to ensure that it doesn't pull that much current (keep the
capacitance of the JFET down) or we could slow down the transient.
Actually, if you consider the time margins we have we could reduce the
slope of the LM311 quite a lot before it becomes a real burden on us,
a Miller capacitor (a capacitor in the negative feedback over the
LM311) is one possible way to acheive this. The benefit of reducing
the slopespeed is that the current peak will be less and thus the
source of the spike becomes less.

Just look at the slow slope (the red signal in the picture) as we
start turning the JFET on, why not just let the turn off slope become
something similar to cure away many problems?

Also note that I made this measurement on both extermes of my ASM-1 VCO
both at 88 mHz operation (the picture you got) and on 106 kHz
operation and the LM311 waveform and the noise it induces is the same.

So, to end this little adventure, I think there are several ways to
cure the problem and changing the slope speed rather than keeping to a
low capacitance is one things one can do. The falltime of the raw
sawtooth is 737 ns so a slower turnoff time is reasonble.

As this impulse moves along the -15V line it sneaks in to place we
would not like it and there it can cause a form of syncing of the
other oscillator.

Cheers,
Magnus

-------------- next part --------------
?PNG


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From roytate at ionet.net  Sun Jan 24 04:16:22 1999
From: roytate at ionet.net (Roy Tate)
Date: Sat, 23 Jan 1999 21:16:22 -0600
Subject: Invert ADSR (Modulus #4)
Message-ID: <36AA9086.D0195ADD@ionet.net>

From: 
        Roy Tate <roytate at ionet.net>
                                                                                       
8:18 PM

 Subject: 
        Re: Invert ADSR (Modulus #4)
     To: 
        gerryd at ntx-tech.com




Gerry Dahl wrote: 
> Hi Everyone,
> I'm looking for a way to invert the ADSR And the A(S)R on my PAIA
> Fatman. Any help on this would be great.
> Thanks.

I'll address the question "how do I invert a voltage."  I'm sorry, but I
won't be addressing the issue of using this circuit in a PAIA Fatman.

[A simple circuit]

You need an Op-Amp such as the TL071.  Use the following schematic, but
you may have to figure out the resistor values for yourself.  If you
want "unity gain" - where the input voltage equals the output voltage,
set Ra and Rb to the same value - between 1K Ohms and 100K Ohms, I would
try 100K as a starter.  Technically, this is a gain of -1 since
the output is inverted.  Power the op-amp from +/-12V or 15V (the
same power as the Fatman uses).  Normally, a 1K Ohm resistor is 
attached to pin 6 to limit the output current in case of a short to
ground later on down the signal chain (among other reasons).

Pinout:
Pin 2: Inverting Input
Pin 3: Non-Inverting Input
Pin 4: -12 or -15V
Pin 6: Voltage Out
Pin 7: +12 or +15V

Voltage In >----Ra----+-----Rb----+---1K---> Inverted Voltage
                      |           |
                      |    |\     |
    (Inverting Input) +----| \    |
                           |TL\___/
                           |71/
(Non-Inverting Input) +----| /
                      |    |/
                   Ground

Gain = -Rb / Ra

Walter Jung's IC Op-Amp cookbook has a more detailed formula on page 19
for the curious.  ISBN 0-672-22453-4.  This book covers op-amps in
general, and does not really discuss analog music synthesizer.

[The circuit you want]

There is a CV inverter module in an issue of the Modulus on-line
magazine.  Get issue #4 and look at page 6 for a schematic that inverts
and adds -10V using the 10K and 20K resistors at the top (simple
resistor divider).  You can look at the point between the 10K and 20K
resistors as another input voltage if you wish.  The Modulus CV Inverter
uses the classic "inverting summer" technique, where all of the voltages
on the left side are fed through resistors of the same value (in this
case 100K) with a 100K feedback resistor, so that we can view the op-amp
as adding the voltages together and inverting the result.  
Pin 6 of the op-amp presents us with the sum of all input voltages 
as long as the result is within the range of the power supply - 
between Pin 4 and Pin 7.  This converts a signal that goes from 0 
to 10 Volts into a signal that goes from 10 to 0 Volts.  "My" 
schematic would take 0 to 10 and convert it into 0 to -10.  You 
probably want to use the schematic from Modulus #4, since it 
requires you to know less about the Fatman's internals - like can 
the Fatman even handle negative envelopes...

Http://www.geocities.com/siliconvalley/park/2707/

If the Fatman uses 5 volt gates, you could use swap the 10K and 20K
resistors for a 5 Volt system.

[Learning More]

If you would look at the various schematics for VCOs and VCFs, you will
find that they are very similar to the Modulus #4 circuit.  Also, more
information on the inverting summer structure is available if you want
to buy the Electro-Notes complete back-issue set (see the Midwest Analog
Products link on my page).  This is an expensive purchase, but
a large percentage of the material is relevant to Analog Synth Design.

Although I'm no expert, I hope that I have helped and not hindered.  If
any other synth-diy member wishes to clarify a point or (especially)
correct some information, please do.

Regards,

Roy Tate
roytate at ionet.net
http://www.ionet.net/~roytate
-------------- next part --------------
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Subject: Re: Invert ADSR (Modulus #4)
Date: Sat, 23 Jan 1999 20:18:02 -0600
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From uhb17 at rzserv2.fh-lueneburg.de  Sun Jan 24 05:02:18 1999
From: uhb17 at rzserv2.fh-lueneburg.de (Heiko Bajus)
Date: Sun, 24 Jan 1999 05:02:18 +0100
Subject: Front Panels (in Germany, too)
Message-ID: <3.0.1.32.19990124050218.007e6a00@rzserv2.fh-lueneburg.de>

At 04:09 PM 1/22/99 -0000, you wrote:
>Has anyone tried anything similar to the front panel anodising system shown
>at? http://www.megaelect.demon.co.uk/gedakop.html
><http://www.megaelect.demon.co.uk/gedakop.html>  ?
>It's basically a pre-sensitised aluminium sheet that you expose artwork on
>with a UV box (same as for a PCB), dye it, and seal in the dye in hot water.
>If anyone has used this or similar, I'd be interested to hear how it went.
>?
>If the price if right it could be a very nice way of producing front panels.
>?
>Colin f
>?

Haven't tried them yet, but am interested. Will call them on monday.
Gedakop is also available in Germany:

dD-Produkte-Vertrieb GmbH
          Alex-M?ller-Strasse 18
          D-68766 Hockenheim
          Tel. 06205 7139
          Fax 06205 17513

originally made in Switzerland:
http://www.gedacolor.ch

I wonder what the price may be for one 19"x4Ux3mm Frontpanel!

Heiko




From synth1 at airmail.net  Sun Jan 24 05:45:24 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sat, 23 Jan 1999 22:45:24 -0600
Subject: Re-inventing (?) the VC envelope ?
Message-ID: <003201be4754$5be65800$44e3fea9@p400>

The cat's out of the bag!!!

Yes, JH hit it on the head (as we say!): the Interdesign arrays had *LOTS*
of
great matched NPNs (<2mv Vbe matching) but crummy lateral PNPs.

Paul Schreiber






From roytate at ionet.net  Sun Jan 24 06:32:23 1999
From: roytate at ionet.net (Roy Tate)
Date: Sat, 23 Jan 1999 23:32:23 -0600
Subject: Mitsubishi Digital Echo / Delay
Message-ID: <36AAB067.EE13B814@ionet.net>

Has anybody heard anything about these chips?  Especially, are they
available?  The digital echo seems easy to program.

Mitsubishi Semiconductors - Karaoke Chips!
M65830 Digital Echo (up to 92 dB signal/noise)
M50194 Digital Reverb ( M50194AP )
67405 Surround Sound Processor


[Contact in the US]

Mitsubishi
1050 E Arques Ave
Sunnyvale CA 94086
(408) 730-5900


[Web Pages]

(Digital Echo/Delay - Acrobat PDF)
http://www.mitsubishi-chips.com/data/datasheets/assps/f7.htm

(General Index)
http://www.mitsubishi-chips.com/data/datasheets/assps/index.html

Just curious ...
 
Roy Tate
roytate at ionet.net
http://www.ionet.net/~roytate



From bduggan at netcom.com  Sun Jan 24 11:23:39 1999
From: bduggan at netcom.com (Brett Duggan)
Date: Sun, 24 Jan 1999 02:23:39 -0800 (PST)
Subject: 5PDT/6PDT switches?
Message-ID: <Pine.3.89.9901240210.A22561-0100000@netcom13>


Hello folks,

I am having extreme difficulty locating any suppliers (or even
manufacturers for that matter) of 5PDT or 6PDT switches in either toggle
or slide form.  Does anyone know if these things exist or I am going to 
have to settle for 2 seperate switches?

Thanks very much,
Brett D




From debus at cityweb.de  Sun Jan 24 11:24:35 1999
From: debus at cityweb.de (Ingo Debus)
Date: Sun, 24 Jan 1999 11:24:35 +0100
Subject: noniverting transistor amp
References: <199901220906.TAA27565@uq.net.au> <36A89829.B5C8E983@globaleyes.net>
Message-ID: <36AAF4E1.7216@cityweb.de>

Rob wrote:
> WEll, its for a tb303, so that means I have +12v, +5.333v (which is very
> touchy), and ground..
> so, I guess I could hook up a TL-082 as a comparator, but those take up
> a lot of pcb real estate, and I will have to do the voltage divider
> thing to get it to work on a single sided supply..

Well, when you're using an IC anyway, why not a TTL buffer with open
collector output, like the 7407? You need just one additional resistor
as pullup.

Ingo




From vco at mindspring.com  Sun Jan 24 12:50:33 1999
From: vco at mindspring.com (tomg)
Date: Sun, 24 Jan 1999 06:50:33 -0500
Subject: VCO7a
Message-ID: <199901241157.GAA07172@smtp1.mindspring.com>


Over the weekend I was transfering drawings to the pc when I ran across an
old idea I had of merging the 2A and 3A vco designs. I though I might flesh
it out a little at first I used a 2N4391 but on a whim I plugged a 2N3819
in and the oscillator scaled! I couldn't beleave it so I tore it down and
built it  again. Again it worked. It's very odd for a 2N3819 to work.

I replaced the 2A exp-conv. with the 3A current source. 
Replaced the 2A's 1458s with TLO74 (goodby old op-amps!)
Changed a few resistors to make everything happy.
Replaced the 2N4391 with a 2N3819.  You can still use a 2N4391/92 if you
want.

Why is this a big deal? Well the 2N4391 cost $1.30 - $1.50 ( it's not that
hard to find, but it's a mail-order item in most places) and the 2N3819
cost about $.50 sometimes a lot less (It may be the most common fet on the
planet, you can buy 'em at rs). You can go to any radioshack and buy the
parts for this vco. The fet switched ramp wave is lovely to look at! Sounds
very warm and fat. It sounds like the 2A but cost is in the 3A range.

There is an extra op-amp in the design. I though I would change the descret
NPNs to a LM3046 and use it to build a chip heater. Maybe next time I  move
it.....

http://www.mindspring.com/~vco/misc/pics/vco7a_sd.gif

-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------



From varner at k-online.com  Sun Jan 24 17:31:50 1999
From: varner at k-online.com (Steve Varner)
Date: Sun, 24 Jan 1999 08:31:50 -0800
Subject: Re-inventing (?) the VC envelope ?
References: <003201be4754$5be65800$44e3fea9@p400>
Message-ID: <36AB4AF4.2FA8580D@k-online.com>

Wait, I missed something here...
Did JH mention Interdesign arrays? Also, if the NPN pair is good, can't the
NPN pair be used and the PNPs left unconnected? Or are they all connected in
the chip? Lastly, are these chips defunct?

SV


------------------------------
Paul Schreiber wrote:

> The cat's out of the bag!!!
>
> Yes, JH hit it on the head (as we say!): the Interdesign arrays had *LOTS*
> of
> great matched NPNs (<2mv Vbe matching) but crummy lateral PNPs.
>
> Paul Schreiber






From varner at k-online.com  Sun Jan 24 17:44:57 1999
From: varner at k-online.com (Steve Varner)
Date: Sun, 24 Jan 1999 08:44:57 -0800
Subject: KE4859 = NTE467?
Message-ID: <36AB4E05.1C244A15@k-online.com>

I received the following email from Brian Hartley at NTE Electronics.
Does anyone have specs on the KE4859 so we can compare them to the ones
on the NTE web site?
NTE467 specs:
http://www.nteinc.com/specs/400to499/NTE467.html

SV

-----------------------------------------------------------------
Sir,

  Thank you for your interest in NTE.
KE4859= NTE467 (The pinout is different than the original)

Brian
NTE
-----------------------------------------------------------------




From varner at k-online.com  Sun Jan 24 17:48:19 1999
From: varner at k-online.com (Steve Varner)
Date: Sun, 24 Jan 1999 08:48:19 -0800
Subject: PNP arrays
Message-ID: <36AB4ED0.205567B0@k-online.com>

Speaking of transistor arrays... Does anyone know of a cheap transistor
array with a good matched PNP pair? I haven't found one.

SV




From jhaible at primus-online.de  Sun Jan 24 20:31:39 1999
From: jhaible at primus-online.de (jhaible)
Date: Sun, 24 Jan 1999 20:31:39 +0100
Subject: Re-inventing (?) the VC envelope ?
Message-ID: <19990124233746.8155.qmail@nuernberg2.pop.metronet.de>

> And perhaps using a 4052 as a stage switch? 
> And taking the + env out as as B input for switching to decay stage!! 
> And the gate input to the A input of switch! Both inputs zeroes
> makes release stage, A input high makes Attac stage, A and B input high
> make decay to sustain stage. Ans round we go again, Wheeeeeee!!! 

No CMOS switches here, at least for me. Three cheap npn transistors are
enough for switching the A, D and R CV's. Easier to layout, and less
problematic
with over voltage.
I have the circuit ready and simulated, but I won't publish it before it's
tested.
I just couldn't await to share the VCA core idea as soon as I had tested it
(;->)

But what do I say. Three switches aren't necessary at all. Just connect the
Attack CV to one base, and the other will be shared only by Decay and
Release.
So, only 2 transistors needed for switching.

If you're going to build a VC ADS (like Minimoog and many others), no
switching
is required at all. Just build the VC ADS circuit from my homepage, and
replace the 3080-based core with my new circuit.

I'm planning a full VC Hold-ADSR to be published on my homepage at some
time,
but I have to test it first.

JH.




From synth1 at airmail.net  Sun Jan 24 21:03:40 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 24 Jan 1999 14:03:40 -0600
Subject: Re-inventing (?) the VC envelope ?
Message-ID: <000d01be47d4$a39a7480$3a8afea9@p400>

The CEM chips were all designed using Interdesign arrays. Doug Curtis was
Interdesign's cheif
analog applications engineer.

The company is *LONG* gone!!

Paul Schreiber

-----Original Message-----
From: Steve Varner <varner at k-online.com>
To: synth-diy <synth-diy at mailhost.bpa.nl>
Date: Sunday, January 24, 1999 11:28 AM
Subject: Re: Re-inventing (?) the VC envelope ?


>Wait, I missed something here...
>Did JH mention Interdesign arrays? Also, if the NPN pair is good, can't the
>NPN pair be used and the PNPs left unconnected? Or are they all connected
in
>the chip? Lastly, are these chips defunct?
>
>SV
>
>
>------------------------------
>Paul Schreiber wrote:
>
>> The cat's out of the bag!!!
>>
>> Yes, JH hit it on the head (as we say!): the Interdesign arrays had
*LOTS*
>> of
>> great matched NPNs (<2mv Vbe matching) but crummy lateral PNPs.
>>
>> Paul Schreiber
>
>
>
>




From cyborg0 at GlobalEyes.net  Sun Jan 24 21:58:16 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 24 Jan 1999 14:58:16 -0600
Subject: studio 440 "proprietary" floppy drive
Message-ID: <36AB8968.505F577B@globaleyes.net>

I need a floppy drive primer here... And, yes, I know that this may be a
moot point due to the fact that i will be getting the scsi update and be
able to use my zip drive shortly, but it still bothers me that the
floppy doesn work.

Ok, first question, how does the drive signal to the processor that a
disk is present? I had always though it worked on a beam being broken.
The controller is a WDC1770..

Another thing is, if the floppy IS broken, how hard is it to repair? 
I have had some advise against this, but if the floppy is proprietary,
how else do you make it work?

Given that the WDC1770 controller is fairly standard, what would
preclude me from just hooking up another drive? If i were to know the
pinouts of the drive, why couldnt I just  hook up an ordinary drive? 

Its like saying that a screwdriver will work here, but if its over there
it wont.

Hopefully I just have a few bad ROMs (those little window EEPROMs go bad
once in a while and the programming degenerates). Then I wont have to do
any of this



From patchell at teletrac.com  Sun Jan 24 23:30:52 1999
From: patchell at teletrac.com (patchell)
Date: Sun, 24 Jan 1999 14:30:52 -0800
Subject: PNP arrays
References: <36AB4ED0.205567B0@k-online.com>
Message-ID: <36AB9F1C.B899B5DB@teletrac.com>

    I was just looking at the NTE web page.  I have been looking for a good
easy to get PNP pair as well.  There is one part that caught my eye that
bears investigation.  The NTE42 (npn) and NTE43 (pnp) diff amps.  I do not
know if these are in any way useful, but since the come in a 5 pin sip
package I can only assume that it is a dual transistor with the emmitters
connected in common.  There did not appear to be a data sheet availiable
for them on the web site.  Anybody know anything more about these?

    -Jim

Steve Varner wrote:

> Speaking of transistor arrays... Does anyone know of a cheap transistor
> array with a good matched PNP pair? I haven't found one.
>
> SV

--
-----------------------------------------------------------------
Visit:http://www.silcom.com/~patchell/
-----------------------------------------------------------------





From ijfritz at earthlink.net  Sun Jan 24 23:31:23 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sun, 24 Jan 1999 15:31:23 -0700
Subject: KE4859 = NTE467?
References: <36AB4E05.1C244A15@k-online.com>
Message-ID: <36AB9F3B.4EC59481@earthlink.net>

The 2N4859 spec sheet can be found on the Temic/Siliconix web site:
www.temic.com

  Ian


Steve Varner wrote:
> 
> I received the following email from Brian Hartley at NTE Electronics.
> Does anyone have specs on the KE4859 so we can compare them to the ones
> on the NTE web site?
> NTE467 specs:



From ijfritz at earthlink.net  Mon Jan 25 00:27:38 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sun, 24 Jan 1999 16:27:38 -0700
Subject: J105
References: <36A93C19.773E935A@earthlink.net> <199901240047.BAA27416@mail2.it.kth.se>
Message-ID: <36ABAC6A.B07FDCC8@earthlink.net>

Magnus Danielson wrote:

> I know for a fact that the LM311 is a real noise-makes when I turn the
> FET of in the ASM-1 VCO. I get all kinds of frequencies. I haven't
> cured it but it is time to do so, I am considering a 100 nF or so
> sitting across the LM311 body.

Comparitors are notorious for oscillating as they switch. Good layout
and bypassing are absolutely necessary. I had a lot of trouble with the
LM319 in my version of this circuit. The main problem turned out to be
too large a resistor on the + input. Anyway, you have to have the power
supplies bypassed with about .1muF right at the IC pins.

> So, in true EMC spirit there is several ways to attack the problem,
> one is to ensure that it doesn't pull that much current (keep the
> capacitance of the JFET down) or we could slow down the transient.

Isn't most of the comparitor current going through its output resistor?
I don't see how the small FET capacitance is an issue here.

> Actually, if you consider the time margins we have we could reduce the
> slope of the LM311 quite a lot before it becomes a real burden on us,
> a Miller capacitor (a capacitor in the negative feedback over the
> LM311) is one possible way to acheive this. The benefit of reducing
> the slopespeed is that the current peak will be less and thus the
> source of the spike becomes less.

This might be interesting to try, but the comparitor ICs are optimized
for fast switching, so wouldn't that just be defeating the LM311's
purpose? If you want slower switching why not just use an op amp (like
some of the simple circuits you see around)?

> Just look at the slow slope (the red signal in the picture) as we
> start turning the JFET on, why not just let the turn off slope become
> something similar to cure away many problems?

I'm afraid I wasn't able to see your figure. It came through as garbage
text. 

> So, to end this little adventure, I think there are several ways to
> cure the problem and changing the slope speed rather than keeping to a
> low capacitance is one things one can do. The falltime of the raw
> sawtooth is 737 ns so a slower turnoff time is reasonble.

I wonder if you aren't confusing a couple of different effects here. The
problem with the JFET capacitance is that it couples the switching
signal (at the gate) onto the timing cap (source and drain), so it puts
glitches on the sawtooth waveform. (See Terry's earlier post on this
effect.) The JFET capacitance has a *negligible* effect on the switching
speed. The switching speed is mainly limited -- as I see it -- by (1)
the the integrator opamp's slew rate, (2) the series resistance of the
JFET and (3) the JFET's saturated current limit. I like the idea of
trying the J105 because it improves (2) and (3).  But don't overlook (1)
either. The BB OPA132 I use makes a big improvement and an OPA602 would
probably be even better.

> As this impulse moves along the -15V line it sneaks in to place we
> would not like it and there it can cause a form of syncing of the
> other oscillator.

You might try separate power lines for the LM311 (from the point where
power enters the board directly to the IC).

Good luck, and please continue to keep us informed on your experiments.

  Ian



From zzynt at swipnet.se  Mon Jan 25 00:44:05 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 24 Jan 1999 15:44:05 -0800
Subject: Re-inventing (?) the VC envelope ?
References: <19990124002732.17584.qmail@nuernberg2.pop.metronet.de>
Message-ID: <36ABB045.375D@swipnet.se>

jhaible wrote:
> 
> Ladies and Gentlemen,
> 
> I 'd like to proudly present a circuit for the VCA core of a voltage
> controlled
> envelope generator.

And perhaps using a 4052 as a stage switch? 
And taking the + env out as as B input for switching to decay stage!! 
And the gate input to the A input of switch! Both inputs zeroes
makes release stage, A input high makes Attac stage, A and B input high
make decay to sustain stage. Ans round we go again, Wheeeeeee!!! 


Idi Amin



From zzynt at swipnet.se  Mon Jan 25 00:52:33 1999
From: zzynt at swipnet.se (BJ)
Date: Sun, 24 Jan 1999 15:52:33 -0800
Subject: Mitsubishi Digital Echo / Delay
References: <36AAB067.EE13B814@ionet.net>
Message-ID: <36ABB241.61F5@swipnet.se>

Roy Tate wrote:
> 
> Has anybody heard anything about these chips?  Especially, are they
> available?  The digital echo seems easy to program.
> 
> Mitsubishi Semiconductors - Karaoke Chips!
> M65830 Digital Echo (up to 92 dB signal/noise)
> M50194 Digital Reverb ( M50194AP )
> 67405 Surround Sound Processor

> Just curious ...

Me too , but no specs of D/A resolution, BW of the unit, and no
dynamic data specs!!

In fact i have one of those M- bushi IC's somewhere here, its a Pitch
shifter
IC, both programmable from switches and by a MCU.

Haven't done anything whit it yet!

BJ



From ijfritz at earthlink.net  Mon Jan 25 00:56:34 1999
From: ijfritz at earthlink.net (Ian Fritz)
Date: Sun, 24 Jan 1999 16:56:34 -0700
Subject: Discharge Switches (was: Re: J105 )
References: <199901222312.AAA19173@mail2.it.kth.se> <3.0.5.32.19990123222128.00901520@ibm.rhrz.uni-bonn.de>
Message-ID: <36ABB332.B8312BB5@earthlink.net>

Rene Schmitz wrote:
 
> Don't overlook the leakage effects on the lower end of the scale.
> It would gain nothing if you find a FET with one halve the R(on) and double
> the leakage.

True...but... The J105 "typical" leakage is 10 pA vs. 5 pA for the
2N4859 and 2N4391. Twice as bad indeed, but still much less than for a
MOSFET (e.g., 30 nA for the BS107, 1 muA for the 2N7000, etc.) 

> And two more thoughts on the subject of discharge switches:
> I found an interesting idea in Horowitz & Hill, they show how to make a
> high precision integrator, as switch they use two Fets in series (though
> they use MOSFETS).One has the larger portion of the voltage across it, and
> the other a very small Vds. The middle of this arrangement is grounded via
> a 1M Resistor, so the leakage current of the one with the high voltage
> flows to ground. Kind of a guarding technique. Now what I think is this can
> be done similarly with JFETS (then we would have essentially only gate
> leakage contribution which is 1-10 pA).
> One can use a smaller cap value to bring the speed up at high frequencies.

There are similar (identical?) circuits in Jung's "IC Op-Amp Cookbook".
These came originally from National and Analog Devices. I haven't been
able to find the originals. I would be *very* interested in learning how
to use these techniques with JFETs.

> And the second thing, charge injection from the gate-channel capacitance
> can probably eliminated by adding the inverted discharge signal to the signal
> thru a tiny cap.

Yes, Terry mentioned this possibility also. I'm not aware of anyone
trying it yet. Again, I would be most interested in seeing a circuit if
you work on this.

  Ian



From magnus at analogue.org  Mon Jan 25 02:11:25 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 25 Jan 1999 02:11:25 +0100
Subject: J105
In-Reply-To: Your message of "Sun, 24 Jan 1999 16:27:38 -0700"
References: <36ABAC6A.B07FDCC8@earthlink.net>
Message-ID: <199901250111.CAA13141@mail2.it.kth.se>

>>>>> "IF" == Ian Fritz <ijfritz at earthlink.net> writes:

Hi!

 IF> Magnus Danielson wrote:
 >> I know for a fact that the LM311 is a real noise-makes when I turn the
 >> FET of in the ASM-1 VCO. I get all kinds of frequencies. I haven't
 >> cured it but it is time to do so, I am considering a 100 nF or so
 >> sitting across the LM311 body.

 IF> Comparitors are notorious for oscillating as they switch. Good layout
 IF> and bypassing are absolutely necessary. I had a lot of trouble with the
 IF> LM319 in my version of this circuit. The main problem turned out to be
 IF> too large a resistor on the + input. Anyway, you have to have the power
 IF> supplies bypassed with about .1muF right at the IC pins.

This is certainly true.

 >> So, in true EMC spirit there is several ways to attack the problem,
 >> one is to ensure that it doesn't pull that much current (keep the
 >> capacitance of the JFET down) or we could slow down the transient.

 IF> Isn't most of the comparitor current going through its output resistor?
 IF> I don't see how the small FET capacitance is an issue here.

It has to pull both the cap and the resistor, the faster the transient
is, the higher current value for the cap. If it is an issue, this is
how it interact with the cap. The quick pulling will upset the power
supply lines which will act pretty inductive, a power decoupling is a
good cure for that.

 >> Actually, if you consider the time margins we have we could reduce the
 >> slope of the LM311 quite a lot before it becomes a real burden on us,
 >> a Miller capacitor (a capacitor in the negative feedback over the
 >> LM311) is one possible way to acheive this. The benefit of reducing
 >> the slopespeed is that the current peak will be less and thus the
 >> source of the spike becomes less.

 IF> This might be interesting to try, but the comparitor ICs are optimized
 IF> for fast switching, so wouldn't that just be defeating the LM311's
 IF> purpose? If you want slower switching why not just use an op amp (like
 IF> some of the simple circuits you see around)?

Well, maybe. But then, part of the point with using the LM311 is the
output arrangement (it is hooked up as a open collector). Deliberately
slowing down the slope kills the problem much more at the source than
the power decoupling cap does.

 >> Just look at the slow slope (the red signal in the picture) as we
 >> start turning the JFET on, why not just let the turn off slope become
 >> something similar to cure away many problems?

 IF> I'm afraid I wasn't able to see your figure. It came through as garbage
 IF> text. 

I realized that after I sent it. Let's see if you can do anything with
it this time... (somebody got to fix that mail-tool!).

 >> So, to end this little adventure, I think there are several ways to
 >> cure the problem and changing the slope speed rather than keeping to a
 >> low capacitance is one things one can do. The falltime of the raw
 >> sawtooth is 737 ns so a slower turnoff time is reasonble.

 IF> I wonder if you aren't confusing a couple of different effects here. The
 IF> problem with the JFET capacitance is that it couples the switching
 IF> signal (at the gate) onto the timing cap (source and drain), so it puts
 IF> glitches on the sawtooth waveform. (See Terry's earlier post on this
 IF> effect.) The JFET capacitance has a *negligible* effect on the switching
 IF> speed. The switching speed is mainly limited -- as I see it -- by (1)
 IF> the the integrator opamp's slew rate, (2) the series resistance of the
 IF> JFET and (3) the JFET's saturated current limit. I like the idea of
 IF> trying the J105 because it improves (2) and (3).  But don't overlook (1)
 IF> either. The BB OPA132 I use makes a big improvement and an OPA602 would
 IF> probably be even better.

I may confuse things up, but then you really should see the scope
picture that I have in mind to understand some of what I am talking
about.

In this scope picture I have hooked up a probe onto the integrator
output, a probe at the LM311 collector output and a probe at the CV
summer output. When one moves in on the signal (to a 250 ns/div scale)
you can clearly see that when the LM311 falls you get a very noticable
click on the integrator output. Putting a J105 does not have anything
to do with this click, or at least not as a cure. I noted the strong
time correlance between the LM311 fall and the strong click on the
waveform and started to consider a number of cures:

1) Power decoupling

2) Slew-rate limiting

The benefit of the second is that you avoid getting a strong peaking.
While one might say that the capacitor effect of the FET is small onto
the LM311, the LM311 itself cause enought trouble on the powerline and
reducing the slewrate could be a path to try, this is what one does on
digital systems to keep them quiet (see "High-Speed Digital Design - A
Handbook of Black Magic" by Howard Johnson and Martin Graham").

 >> As this impulse moves along the -15V line it sneaks in to place we
 >> would not like it and there it can cause a form of syncing of the
 >> other oscillator.

 IF> You might try separate power lines for the LM311 (from the point where
 IF> power enters the board directly to the IC).

 IF> Good luck, and please continue to keep us informed on your experiments.

I will.

BTW, did the scope-picture (an PNG format thing) get there now?

Cheers,
Magnus

 IF>   Ian
-------------- next part --------------
?PNG


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?????N?S??;N?N?6?x??M??H?V"?j}+?B?|l?^????S9?V?l???U?M??U?J?J??r?Z?^??=G??	5-F??@i)??5??JCKqs?<?z??Co?;j??3?u?JU??X?a??N)z5.NB??Wi??p??????[???^rd???E?y??? ?qDx?-_.?}?8?|???\???/?C|????rq;?????0-?!h0A?aZC?`?r?????\??\L?.n?y?aZC?`????A????I?!?!??5-?!h0???[???;M?????k?E?y]?/&??-iV?G????l?7????74}?????w?Rgec5?e?t???e????&?V9???u??R?-`v?m'U?B??7?>[)??[u?9-???dx?3_??????qE??=??4?N??????}?D?]LGK?R????.ZueR??t?E??????5??}??i???x????????~G[Z????_pU???"V?????p?K??NY???j??Y??:?[?????N??????]?i?K?)??}z??x?????UU?:?????????p,Q<?z?:?k)_Ve?????:ki???#?B??cSs??6??V????I?M~&hu{^?^c9?}?C??k??"[?5??1I6K;?~?k.???U?-
??E{?????1??Ct?n},R?{??'UZn?	Z?9?W??????O??_???N?????n)??;?????S?"??????=?~??r_U?.W?|?)???M?_<?<?n=?r?]??67?]?r??;?{????'7T???Ecw?#k?b?Y????ww09.??J?XA??y?#?;?_ws?????7|-?:?????W?v?&9QK?????_???_??_??z????6??>7G?tX??K????????(DV??????`]?An???????X??sJ?????$?N??m?4i
?N:???V?/?@??V???G?7?[?K?[??????U&e????c???l:???p???o????{_???+????????u???&2??????t???hR?P?2?s????;M?[?z#ge?M1?>sce??[/??ZX;???????????-????IDAT?'>????e??Tu??????????fV???K??o?k?????|??J?K???4?e???j?`
?????????K??M??NZ?i{?*?J'??	????????????K??)=^J?3'??Z??<?P?o?j??pG??????d,?GNl8?sA??(???'??C???b???C5??P?[??VK?G?)???????-?fp?????R58O??F??W_?T??qdq%?z?'?2he@???{D#?????j_}[??3????F????4??!??S??E.Z??g'???.U_???????V??? ??o?^%?????|PF???/??~?`?1X}????=@?????n??/?????-?b????hx??W????0??~?N?_@???,5-???????Dn??m????o??wh`?*??????FtIME?gC??tEXtCommentImage generated by Aladdin Ghostscript (device=ppmraw)
dCIEND?B`?

From synth1 at airmail.net  Mon Jan 25 03:48:13 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 24 Jan 1999 20:48:13 -0600
Subject: Another good DIY catalog
Message-ID: <001601be480d$273df860$3a8afea9@p400>

Similar to the previously mentioned Techni-Tools.

Contact East
1-800-225-5370
www.contacteast.com


Paul Schreiber





From martin.czech at intermetall.de  Mon Jan 25 08:58:45 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 25 Jan 1999 08:58:45 +0100 (MET)
Subject: PNP arrays
Message-ID: <199901250758.IAA22089@window.intermetall.de>

Harris CA3096 ?

m.c.




From jorgen.bergfors at idg.se  Mon Jan 25 09:48:15 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Mon, 25 Jan 1999 9:48:15 +0100
Subject: PNP arrays
Message-ID: <TFSUYVWC@idg.se>

Or CA3084?

/Jorgen




MIME:martin.czech at intermetall.de on 99-01-25 09:44:49
To:  synth-diy at mailhost.bpa.nl @ SMTP ,  patchell at teletrac.com @ SMTP cc:  (bcc: Jorgen Bergfors/IDGSE)
Subject: Re: PNP arrays 

Harris CA3096 ?

m.c.










From vco at mindspring.com  Mon Jan 25 11:20:32 1999
From: vco at mindspring.com (tomg)
Date: Mon, 25 Jan 1999 05:20:32 -0500
Subject: VCO7b
Message-ID: <199901251026.FAA15146@smtp1.mindspring.com>

> There is an extra op-amp in the design. I though I would change the
descret
> NPNs to a LM3046 and use it to build a chip heater. Maybe next time I 
move
> it.....

It was still on the board so I added the 3046 heater. Warms up nicely! 

 http://www.mindspring.com/~vco/misc/pics/vco7b_sd.gif

 -tg
 --------------------------------------------------------------------------
 Mad Mouse - PC Board - Analog For Everybody
 http://www.mindspring.com/~vco/madm/mm_order.html
 --------------------------------------------------------------------------



From Colin.Fraser at scottishpower.plc.uk  Mon Jan 25 11:41:44 1999
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 25 Jan 1999 10:41:44 -0000
Subject: Slightly OT - balanced to unbalanced cables?
Message-ID: <BA865FF10473D211BC6F00805F0D830702D2CF@catsprntp01.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: Bill Layer [mailto:b.layer at vikingelectronics.com]
> Sent: 22 January 1999 19:40
> To: Fraser, Colin J
> Subject: RE: Slightly OT - balanced to unbalanced cables?
> 
> >Wiring pin 1 & 3 together wil give you gnd (by fixing the 
> -ve signal at
> >earth), and pin 2 will be the signal, but (IIRC) you will 
> end up with twice
> >the signal level at pin 2 and may overdrive input stages. 
> 
> Ummm.... not to step on any toes, but that doesn't sound 
> right. In a true
> differential system, if you tie 1 to 3, you neither gain nor 
> lose any signal.

This isn't a true balanced system - it's a balanced output driving a
single-ended input.

> A level change will ocurr if you are driving a balanced load, and then
> begin to drive it single-ended. In that case, you will lose 
> 6db of gain as
> the diff-stage loses sensitivity when half of it is tied to ground.

That's true.
At a balanced *input* the -signal is subtracted from the +signal. This gives
2 x signal, which is then reduced by 6db to give just the signal.
When you drive a balanced input from a single ended output, the -signal line
should be tied to ground, so subtracting -signal from +signal only gives you
1 x signal, so you lose 6db. Some gear has balanced inputs that detect if
the -signal line is connected to gnd, and compensate by not dropping the
6db.

My understanding is that if you take a balanced *output*, and tie -signal to
ground, then the +signal should still be driven such that
(+signal)-(-signal) is 2 x signal, giving you an extra 6db if you connect
+signal to a single ended input.
Is that not correct ?


Colin f



From allan.houston at lineone.net  Mon Jan 25 13:49:20 1999
From: allan.houston at lineone.net (Allan)
Date: Mon, 25 Jan 1999 12:49:20 -0000
Subject: Designing a VCO/simple alternative to paia Midi2cv8.
Message-ID: <002c01be4861$20733000$66f1abc3@default>

How would I go about designing my own VCO.  I just want a simple(ish)
sawtooth waveform, and I'm not sure how to start.

Also the MIDI2CV8 seems overcomplicated for my requirements.  I just need
the control voltage for the pitch of the note.

Apologies for the simple questions, but I got to start somewhere,

cheers
Allan




From jocke at netcontrol.fi  Mon Jan 25 13:51:06 1999
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Mon, 25 Jan 1999 14:51:06 +0200 (EET)
Subject: VC envelope idea
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5820127DAFB@nbgm336a.nbgm.siemens.de>
Message-ID: <Pine.LNX.3.96.990125143236.26717E-100000@alf.netcontrol.fi>

Hi again,

I also built your VC lag circuit during the weekend -- couldn't
resist, it's such a clever circuit.

For the first circuit I built I used 2N3904/3906 transistors,
and it worked immediately. Then I changed to ZTX109C/214C high
gain transistors, and I got this odd diode-drop offset on the
output all the time. I changed R2 from 22K to 39K, and it worked
okay again. I wonder what this phenomenon is due to. Reverse
leakage in the transistors due to spikes at the output of U5?

Anyhow, the circuit works very well overall, slopes are RC-shaped
down to around 5 ms, below which they get linearised. There might
be some slight distortion in the RC-shape for negative slopes if
you use medium-gain PNPs, as the base current through Q1 may get
quite high (momentarily, at the beginning of the slope), but the
error is probably negligible for most applications.

Output-to-input error is very small if you match the two 100K
resistors (R6, R9), and offset performance is mainly determined
by the op-amps used.

Conclusion: Juergen is a genius. (As if there ever was any doubt
about that).  :-)

-joachim





From Juergen.Haible at nbgm.siemens.de  Mon Jan 25 14:49:20 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 25 Jan 1999 14:49:20 +0100
Subject: AW: VCO7b
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5820129C581@nbgm336a.nbgm.siemens.de>

> It was still on the board so I added the 3046 heater. Warms up nicely! 
> 
>  http://www.mindspring.com/~vco/misc/pics/vco7b_sd.gif
> 
> 
You must heat the reference transistor, too. Otherwise you
will have more drift than before.
(You surely know that, but the picture still shows a 3904 there.)

JH.



From gerryd at ntx-tech.com  Mon Jan 25 17:43:56 1999
From: gerryd at ntx-tech.com (Gerry Dahl)
Date: Mon, 25 Jan 1999 08:43:56 -0800
Subject: Another good DIY catalog
References: <001601be480d$273df860$3a8afea9@p400>
Message-ID: <36AC9F4C.38B3@ntx-tech.com>

Paul Schreiber wrote:
> 
> Similar to the previously mentioned Techni-Tools.
> 
> Contact East
> 1-800-225-5370
> www.contacteast.com
> 
> Paul Schreiber

I don't know if anyone has mentioned this one,
Tech America  www.techam.com
100 resisters for $1.00
Woo-Hoo!!!

Gerry



From patchell at teletrac.com  Mon Jan 25 18:10:55 1999
From: patchell at teletrac.com (Jim Patchell)
Date: Mon, 25 Jan 1999 09:10:55 -0800
Subject: PNP arrays
References: <199901250758.IAA22089@window.intermetall.de>
Message-ID: <36ACA59F.1540729B@teletrac.com>

    Just got back a fax from NTE.  The NTE42 (npn)  and NTE43 (pnp) are
dual transistors connected as differential amplifiers, ie the emmiters
are sharing a pin.  According to the spec sheet maximum delta Vbe is
10mV.  Not exactly supper matched by a long shot.  Typical delta Vbe is
1mv.  Beta is listed at minimum of 400.  The price in the mouser catalog
is about $1.90 for the npn and $2.00 for the pnp.  And these are
complementary transistors.

    The problem with the CA3096 is that the PNP transistors in that part
are lateral.  This means poor high frequency characterists at the best.
Have not looked into them too much further.  I have used the CA3096 in
the past, don't really know how good the PNP's would work in exponential
converters and the like.

    I have not been able to yet locate any information on the CA3084.

Martin Czech wrote:

> Harris CA3096 ?
>
> m.c.






From jbrookes at bluebear.freeserve.co.uk  Mon Jan 25 18:53:17 1999
From: jbrookes at bluebear.freeserve.co.uk (Jezz Brookes)
Date: Mon, 25 Jan 1999 17:53:17 -0000
Subject: MIDI activity LED
Message-ID: <000f01be488b$b459ca70$01010101@aardvark>

Having seen these for sale (a 5-pin DIN with an LED in pace of the lead out)
I figured they can't be worth the money they're charging. I'm guessing it's
just a LED in series with a 150ohm resistor? Am I right in thinking MIDI is
20mA current loop, switching 0-5V?





From vco at mindspring.com  Mon Jan 25 19:18:29 1999
From: vco at mindspring.com (tomg)
Date: Mon, 25 Jan 1999 13:18:29 -0500
Subject: VCO7b
Message-ID: <199901251824.NAA01606@camel14.mindspring.com>



----------
> From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
> To: DIY <synth-diy at mailhost.bpa.nl>; tomg <vco at mindspring.com>
> Subject: AW: VCO7b
> Date: Monday, January 25, 1999 8:49 AM
> 
> > It was still on the board so I added the 3046 heater. Warms up nicely! 
> > 
> >  http://www.mindspring.com/~vco/misc/pics/vco7b_sd.gif
> > 
> > 
> You must heat the reference transistor, too. Otherwise you
> will have more drift than before.
> (You surely know that, but the picture still shows a 3904 there.)

> JH.

Sorry you're right. I've removed it.

-tg





From magnus at analogue.org  Mon Jan 25 21:00:04 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 25 Jan 1999 21:00:04 +0100
Subject: High-Speed Digital Design -Handbook of Black Magic"
In-Reply-To: Your message of "Sun, 20 Apr 1997 21:24:58 +1000"
References: <1.5.4.32.19970420112458.00d0dad4@popa.melbpc.org.au>
Message-ID: <199901252000.VAA07113@mail2.it.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 PP> At 02:11 AM 25/01/99 +0100, Magnus Danielson wrote:
 PP> see "High-Speed Digital Design - A
 PP> Handbook of Black Magic" by Howard Johnson and Martin Graham"

 PP> I've always wanted to see this, ever since I noticed on Amazon that
 PP> 'people who bought 'Troubleshooting Analog Ckts" also bought' this..

 PP> but, I'm pretty broke these days, so I cant just buy it 'on spec'.
 PP> Anyone care to comment on how useful it is? There aren't any in
 PP> Melbourne to look at, AFAIK.
 PP> I figure all 'difficult' digital problems ae analog, so....

Well, on my bookpage I write:

    This is a very good book for those seeking hands-on tips on how to
    really design and measure high-speed digital designs. This book 
    doesn't describe any of that digital theory, it assumes you know
    that and just have trouble making good designs. It is a very
    crash-coarse oriented book that certainly helped me to clear up
    several issues. Here you learn the troubles of bypass capacitors,
    paths of currents, impedance mathching etc. A lot of these
    techniques makes sound reading even for more modest analog designs.

It helps you both to design, find errors and redesign. When you go
just above hearing range (say 200 MHz or so ;) you really need
something like this.

First I got one for myself, and then I bougth 4 for work and spread
them over the hardware department (rather, sneaked them onto the table
of people in deep need for it).

Cheers,
Magnus




From vco at mindspring.com  Mon Jan 25 21:16:19 1999
From: vco at mindspring.com (tomg)
Date: Mon, 25 Jan 1999 15:16:19 -0500
Subject: VCO7b
Message-ID: <199901252021.PAA29597@smtp3.mindspring.com>



----------
> From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
> To: DIY <synth-diy at mailhost.bpa.nl>; tomg <vco at mindspring.com>
> Subject: AW: VCO7b
> Date: Monday, January 25, 1999 8:49 AM
> 
> > It was still on the board so I added the 3046 heater. Warms up nicely! 
> > 
> >  http://www.mindspring.com/~vco/misc/pics/vco7b_sd.gif
> > 
> > 
> You must heat the reference transistor, too. Otherwise you
> will have more drift than before.
> (You surely know that, but the picture still shows a 3904 there.)
> 
> JH.

Rearranged things a little. This should be better..

http://www.mindspring.com/~vco/misc/pics/vco7c_sd.gif

-tg






From buchanan at qualcomm.com  Mon Jan 25 21:24:45 1999
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Mon, 25 Jan 1999 12:24:45 -0800
Subject: 5PDT/6PDT switches?
In-Reply-To: <Pine.3.89.9901240210.A22561-0100000@netcom13>
Message-ID: <3.0.3.32.19990125122445.017a0580@mage.qualcomm.com>

At 02:23 AM 1/24/99 -0800, Brett Duggan wrote:
>I am having extreme difficulty locating any suppliers (or even
>manufacturers for that matter) of 5PDT or 6PDT switches in either toggle
>or slide form.  Does anyone know if these things exist or I am going to 
>have to settle for 2 seperate switches?

I too have always been on the lookout for these items and have only found
them consistently in two forms: 1) Big beefy 120VAC 10+amp things (too big
for *most* synths) and 2) at the local electronics swap meet but this
really isn't consistent and I don't think I've seen bigger than 4 pole (+
they seems kinda cheap....).

If you can settle for a rotary, the nice ones like Grayhill and others have
several models with multiple ganged sections.  These almost always have a
position stop so you might have to get something like a 6 pole 12 position
and set the stop for just 2 positions.

Just an option.  If you do find a reliable source on high quality
multi-pole toggles, please post it to the list!

Thanks,

Buck



From vco at mindspring.com  Mon Jan 25 22:25:44 1999
From: vco at mindspring.com (tomg)
Date: Mon, 25 Jan 1999 16:25:44 -0500
Subject: vco7c thermal results
Message-ID: <199901252131.QAA18014@smtp3.mindspring.com>

I did a few experiments for the fun of it. I set the vco at 440hz then
sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
about 60secs to recover to 440hz then after a little minor drifting
stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
in the middle of the 3046 for 30secs. The freq went down to 382hz again it
took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
got out the hair dryer full bore and max heat about 6" from the board for
30secs freq went down to 332hz and took about 5mins to fully recover.
 
-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------



From vco at mindspring.com  Mon Jan 25 22:30:45 1999
From: vco at mindspring.com (tomg)
Date: Mon, 25 Jan 1999 16:30:45 -0500
Subject: Fw: VCO7b
Message-ID: <199901252136.QAA01709@smtp3.mindspring.com>



----------
> From: tomg <vco at mindspring.com>
> To: synth-diy at mailhost.bpa.nl; Haible Juergen
<Juergen.Haible at nbgm.siemens.de>
> Subject: Re: VCO7b
> Date: Monday, January 25, 1999 3:16 PM
> 
> 
> 
> ----------
> > From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
> > To: DIY <synth-diy at mailhost.bpa.nl>; tomg <vco at mindspring.com>
> > Subject: AW: VCO7b
> > Date: Monday, January 25, 1999 8:49 AM
> > 
> > > It was still on the board so I added the 3046 heater. Warms up
nicely! 
> > > 
> > >  http://www.mindspring.com/~vco/misc/pics/vco7b_sd.gif
> > > 
> > > 
> > You must heat the reference transistor, too. Otherwise you
> > will have more drift than before.
> > (You surely know that, but the picture still shows a 3904 there.)
> > 
> > JH.
> 
> Rearranged things a little. This should be better..
> 
> http://www.mindspring.com/~vco/misc/pics/vco7c_sd.gif
> 
> -tg
> 
> 
> 



From oakley at techrepairs.freeserve.co.uk  Mon Jan 25 23:43:37 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Mon, 25 Jan 1999 22:43:37 -0000
Subject: 5PDT/6PDT switches?
Message-ID: <000e01be48b4$2ce57160$826b883e@default>

How about tape recorder spares. The rec/play switch has more poles than
you could ever want. You may need to have some sort of arrangement from
your front panel to move the slider, but it may work.

Or how about an analogue switch like a 4066 etc? In fact, try the DG2xx,
they have changeovers.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From cyborg0 at GlobalEyes.net  Tue Jan 26 01:51:28 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Mon, 25 Jan 1999 18:51:28 -0600
Subject: 5PDT/6PDT switches?
References: <000e01be48b4$2ce57160$826b883e@default>
Message-ID: <36AD1190.42A8275D@globaleyes.net>

Tony Allgood wrote:
> 
> How about tape recorder spares. The rec/play switch has more poles than
> you could ever want. You may need to have some sort of arrangement from
> your front panel to move the slider, but it may work.
> 
> Or how about an analogue switch like a 4066 etc? In fact, try the DG2xx,
> they have changeovers.
> 
for certain things, the 4066 isnt all that good...
rob



From 104065.2340 at compuserve.com  Tue Jan 26 02:41:19 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Mon, 25 Jan 1999 20:41:19 -0500
Subject: PNP arrays
Message-ID: <199901252042_MC2-67F7-FC86@compuserve.com>

Message text written by Jim Patchell
>   I have not been able to yet locate any information on the CA3084.

Martin Czech wrote:

> Harris CA3096 ?
><

Hi Jim:
I have data sheets on both devices.  The CA3084 has reasonable matching: 
Vbe matching is 0.422 mV typical, 6 mV Max, although typical Hfe is only
40.  The CA3096 has a similar matching spec., Hfe is a little higher.  If
you need a copy of the data sheets, I could scan them with my fax machine,
convert that to a .gif, and e-mail it to you.  As you noted, the high
frequency response of the CA3096 is lousy, the CA3084 looks about the same.

Terry Michaels  



From budweiser at ozemail.com.au  Tue Jan 26 04:13:27 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Tue, 26 Jan 1999 13:43:27 +1030
Subject: 5PDT/6PDT switches?
Message-ID: <017d01be48d9$d8505900$b8a66ccb@ppp.ozemail.com.au>





>How about tape recorder spares. The rec/play switch has more poles than
>you could ever want. You may need to have some sort of arrangement from
>your front panel to move the slider, but it may work.


I use a standard 4 pole switch for changing between low tom and 909 kick
in the 606 Modbox. It effectively switches between 2 completely different
circuits.
Its kind of impractical, because i have 8 wires going between the external
modbox
and the 606.

Maybe a multipole relay would be useful?


<bUd>




From dragonser at clara.net  Tue Jan 26 04:26:17 1999
From: dragonser at clara.net (Peter Blackett)
Date: Tue, 26 Jan 1999 03:26:17 +0000
Subject: info on Panasonic BBD's found
Message-ID: <36AD35D9.9C2ADB1A@clara.net>

Hi there,
just found the following page with some details on Mn3xxx  series BBd
delay ic's.
http://www.mec.panasonic.co.jp/e-index_catalog.html
hope this is usefull  !
regards Peter 
South London England




From patchell at teletrac.com  Tue Jan 26 04:35:14 1999
From: patchell at teletrac.com (patchell)
Date: Mon, 25 Jan 1999 19:35:14 -0800
Subject: PNP arrays
References: <199901252042_MC2-67F7-FC86@compuserve.com>
Message-ID: <36AD37F2.E0C760D1@teletrac.com>

    Thanks Terry:

    Somebody I know has an old RCA linear book that has the part in it.  I am a
little dubious of the part for a few reasons.  It does not appear on the Harris
Web sight.  I would assume that this is because it is no longer manufactured,
at least by Harris.  Second, it is not availiable from Mouser or Digikey,
although, I did find at least one place on the web that said they had them for
sale.

    By the way, Harris has a part called the HFA3096. Ft on these parts is up
in the GHz range.  Vcbo is only 12 volts.  I suspect they are costly as well.

    I did, just for the fun of it go down to our local electronics store (Dow
Marvac), and was surprised as heck that they had both the NTE42 and NTE43 in
stock.  These people never have what I need.  Bought one of each to fiddle
around with and see if the merit a larger purchase.

    -Jim

terry michaels wrote:

>
> Hi Jim:
> I have data sheets on both devices.  The CA3084 has reasonable matching:
> Vbe matching is 0.422 mV typical, 6 mV Max, although typical Hfe is only
> 40.  The CA3096 has a similar matching spec., Hfe is a little higher.  If
> you need a copy of the data sheets, I could scan them with my fax machine,
> convert that to a .gif, and e-mail it to you.  As you noted, the high
> frequency response of the CA3096 is lousy, the CA3084 looks about the same.
>
> Terry Michaels

--
-----------------------------------------------------------------
Visit:http://www.silcom.com/~patchell/
-----------------------------------------------------------------





From donaldj at infomatch.com  Tue Jan 26 06:44:12 1999
From: donaldj at infomatch.com (Donald Johnson)
Date: Mon, 25 Jan 1999 21:44:12 -0800
Subject: PNP arrays
Message-ID: <3.0.1.32.19990125214412.009b3e10@mail.infomatch.com>

Future/Active here in Canada sell quad 2N2907(PNP)/2N2222(NPN) in 14 pin dips.
They also have quad 2N3906/2N3904 in the same 14 pin dip package. The 2N
prefix seems to be replaced with MPQ. (e.g. MPQ2907) I don't know if they
merely 4 transistors packaged in a single dip, or if they are on a single
chip, etc. I'll try to dig up some information. Anyone else seen or used them?

don.


( (        don johnson        ) )
 \ \                         / /
) ) ) donaldj at infomatch.com ( ( (
 / /                        \ \
( (            -             ) )



From jorgen.bergfors at idg.se  Tue Jan 26 08:18:18 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 26 Jan 1999 8:18:18 +0100
Subject: vco7c thermal results
Message-ID: <TFSWSYDD@idg.se>

>I did a few experiments for the fun of it. I set the vco at 440hz then
>sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
>about 60secs to recover to 440hz then after a little minor drifting
>stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
>in the middle of the 3046 for 30secs. The freq went down to 382hz again it
>took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
>got out the hair dryer full bore and max heat about 6" from the board for
>30secs freq went down to 332hz and took about 5mins to fully recover.
 >-tg

This might indicate that the temperature compensation does not work, but on the other hand these tests are rather extreme. You should perform some tests that more resemble normal use. Around ten degrees change inside the synth is probably realistic when you do a live gig. This corresponds to a larger change in free air, as the synth case isolates  more than you would expect. For studio use the temperature variation ought to  be less.
Below is an example how you can do a real world temperature test:

I put the VCO board (size 50 x 75 mm, 2 x 3") in a shoe box and put on the lid. 20 cm (8") from the box I placed a 300 watt infrared heater. After 15 minutes the temperature inside the box had rised from 24 to 34 degrees C. This was less than expected, as the box was just bearable to touch on the outside (the side facing the heater).
With the tempco the frequency of the VCO increased from 518 to 523 Hz. This corresponds to 17 cents or 1/6 of a semitone. With the tempco replaced by a normal 1% metal film resistor, the frequency increased from 424 to 470 Hz. That's 190 cents or almost two semitones.

/Jorgen






From mirwin1 at istar.ca  Tue Jan 26 09:23:24 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Tue, 26 Jan 1999 03:23:24 -0500
Subject: PNP arrays
References: <199901252042_MC2-67F7-FC86@compuserve.com>
Message-ID: <36AD7B7B.33E4554@istar.ca>

Hi,
You can use the following URL to get to the linear datasheets ( pdf
format ) at the Harris Semiconductor website:

http://www.semi.harris.com/families/linear.htm

The CA3046 and CA3096 data sheets are there, but the CA3084 is not. Most
of the old RCA stuff can be found here.




From martin.czech at intermetall.de  Tue Jan 26 09:29:12 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 26 Jan 1999 09:29:12 +0100 (MET)
Subject: PNP arrays
Message-ID: <199901260829.JAA29687@window.intermetall.de>

I use the CA3096 for the expo converter in my version of the WASP filter
clone by J.H..  I know that the pnp are crap, but I hope that they work
for this application (the cicuit works, but I never checked tracking).

hfe of 40 is no good for an expo converter, but the hfe figure should
be better for lower currents. And I have thermal matching, and even on
chip heatimng by the three npn. So the hope is that this pnp pair will
be able to feed a ca3080 current source for my tri osc. in a reasonable
way, so that I get acceptable tracking in the lower octaves, where it
is more about leakage. I hope that a can "invent" some kind of tracking
adjust for the higher octaves, so that it will track there as well.

OTOH I want linear control as well (e.g. hard sync linear sweeps).
I guess I won't be able to adjust ecpo and linear tracking at the
same time.

So it would certainly be better to use a pnp-pair with more performance,
but the few parts that are on the market don't allow for chip heating...
and that means that the thermal error will be much worse then the scaling
error because of low hfe, we had just a mail about thermal results...


m.c.




From martin.czech at intermetall.de  Tue Jan 26 09:38:53 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 26 Jan 1999 09:38:53 +0100 (MET)
Subject: current source measurements
Message-ID: <199901260838.JAA29708@window.intermetall.de>

It would be a nice thing if one would be able to measure expo current
sources allone, because this would allow to decide if e.g. the osc. error
comes from osc. delays or current source errors.

The idea is: use a very big MKT or other foil type cap , say 10uF in
an saw osc. arrangement. measure the charge time only (not the discharge time,
the discharge doesn't need to be fast at all this way).

If Imax is 1mA and dU is 10V => t=0.1 sec.
This time is long enough to measure precisely with a quartz counter,
it is maybe even too long.

There was an elektor (?) proposal long time ago where a cap measurement
box was discussed, using precision R for the current an a counter
for time measurement. This seemed to work.`


Any comments ?

m.c.




From martin.czech at intermetall.de  Tue Jan 26 09:43:25 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 26 Jan 1999 09:43:25 +0100 (MET)
Subject: vco7c thermal results
Message-ID: <199901260843.JAA29722@window.intermetall.de>

> This might indicate that the temperature compensation does not work,
>but on the other hand these tests are rather extreme. You should perform
>some tests that more resemble normal use. Around ten degrees change
>inside the synth is probably realistic when you do a live gig.

Yes , short time.

It would be nice, if the machine stays in tune all the time during the year.
And then Ta might change from 40C to 15C (in my living room).


m.c.




From romanv at mx3.redestb.es  Tue Jan 26 09:51:58 1999
From: romanv at mx3.redestb.es (Roman Vargas)
Date: Tue, 26 Jan 1999 09:51:58 +0100
Subject: Roland JUNO 106 CHIP
Message-ID: <36AD822E.9C9C4F2B@mx3.redestb.es>

Hi,


I'm searching for this chip:
Ref.     15229817OA (?O=0?)
name:    ALQH80017A

I need two of them for my JUNO 106.

Four months ago I read in Future Music that roland was distributing old
synths chips again but I don't know where to find them.


Thanx.

Roman.




From rsowa at WizjaTV.pl  Tue Jan 26 10:04:10 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Tue, 26 Jan 1999 10:04:10 +0100
Subject: ODP: Another good DIY catalog
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D68DC@demon>

And how about this one:
www.slawmir.com.pl
100 resistors for $0.27!!!!

Roman

> -----Oryginalna wiadomo??-----
> Od:	Gerry Dahl [SMTP:gerryd at ntx-tech.com]
> Wys?ano:	25 stycznia 1999 17:44
> Do:	Paul Schreiber
> DW:	synthDIY
> Temat:	Re: Another good DIY catalog
> 
> Paul Schreiber wrote:
> > 
> > Similar to the previously mentioned Techni-Tools.
> > 
> > Contact East
> > 1-800-225-5370
> > www.contacteast.com
> > 
> > Paul Schreiber
> 
> I don't know if anyone has mentioned this one,
> Tech America  www.techam.com
> 100 resisters for $1.00
> Woo-Hoo!!!
> 
> Gerry



From zzynt at swipnet.se  Tue Jan 26 10:19:01 1999
From: zzynt at swipnet.se (BJ)
Date: Tue, 26 Jan 1999 01:19:01 -0800
Subject: High-Speed Digital Design -Handbook of Black Magic"
References: <1.5.4.32.19970420112458.00d0dad4@popa.melbpc.org.au> <199901252000.VAA07113@mail2.it.kth.se>
Message-ID: <36AD8885.42E3@swipnet.se>

Magnus Danielson wrote:

> First I got one for myself, and then I bougth 4 for work and spread
> them over the hardware department (rather, sneaked them onto the table
> of people in deep need for it).
> 
> Cheers,
> Magnus

Well done , thats the right thing to do ! :)

BJ



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Date: Tue, 26 Jan 1999 10:25:27 +0100
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From vco at mindspring.com  Tue Jan 26 10:45:27 1999
From: vco at mindspring.com (tomg)
Date: Tue, 26 Jan 1999 04:45:27 -0500
Subject: vco7c thermal results
Message-ID: <199901260951.EAA11474@camel8.mindspring.com>



----------
From: jorgen.bergfors at idg.se
To: vco at mindspring.com; synth-diy at mailhost.bpa.nl
Subject: Re: vco7c thermal results
Date: Tuesday, January 26, 1999 2:18 AM

>I did a few experiments for the fun of it. I set the vco at 440hz then
>sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
>about 60secs to recover to 440hz then after a little minor drifting
>stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
>in the middle of the 3046 for 30secs. The freq went down to 382hz again it
>took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
>got out the hair dryer full bore and max heat about 6" from the board for
>30secs freq went down to 332hz and took about 5mins to fully recover.
 >-tg

This might indicate that the temperature compensation does not work, but on
the other hand these tests are rather extreme. You should perform some
tests that more resemble normal use. Around ten degrees change inside the
synth is probably realistic when you do a live gig. This corresponds to a
larger change in free air, as the synth case isolates  more than you would
expect. For studio use the temperature variation ought to  be less.
Below is an example how you can do a real world temperature test:

I put the VCO board (size 50 x 75 mm, 2 x 3") in a shoe box and put on the
lid. 20 cm (8") from the box I placed a 300 watt infrared heater. After 15
minutes the temperature inside the box had rised from 24 to 34 degrees C.
This was less than expected, as the box was just bearable to touch on the
outside (the side facing the heater).
With the tempco the frequency of the VCO increased from 518 to 523 Hz. This
corresponds to 17 cents or 1/6 of a semitone. With the tempco replaced by a
normal 1% metal film resistor, the frequency increased from 424 to 470 Hz.
That's 190 cents or almost two semitones.

/Jorgen

I think it's ok. I just push things too far, I wanted to put it in the oven
but the wife said no! It was more like NO!  Ambient temp changes of +10-20o
with a hair drier and cooling had no real effect on the pitch, about like
your tempco results. I didn't do or post the results of non-heater test
because I thought the heater test were so good. I have been forced to
change my opinion about heaters, I guess it is worth the supply drain for
the stability. Gonna have to put a bigger heat sink on those regulators
though. Anyway I pulled the 470 ohm resistor to shut the heater off and let
it run for 5mins. I set the freq for 440hz. I sprayed freeze on the 3046
for 1sec. The freq went up to 528hz and after about 15mins I gave up and
used my finger to heat it up enough to get it stable. It never made it back
to 440hz at any point on it's own, I had to re-adjust it. I let it run for
another 10mins before I did the iron test. After 30secs the freq went down
to 425hz and again I gave up after about 15mins. It never made it back to
440hz on it's own.
These are not the kinds of tests you do no a non-tempcomped
circuit....obtusely. I wonder how your tempco would react to such extremes.
Anybody want to hurt your vco (compensation of your choice) a little for a
comparison? BTW when I said "then after a little minor drifting" maybe
+-5hz .It was useable at the initial frequency within 60secs of being
thermally slammed. I though that was pretty good. 

-tg 




From jorgen.bergfors at idg.se  Tue Jan 26 11:09:35 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Tue, 26 Jan 1999 11:09:35 +0100
Subject: vco7c thermal results
Message-ID: <TFSWYUDU@idg.se>

>These are not the kinds of tests you do no a non-tempcomped
>circuit....obtusely. I wonder how your tempco would react to such extremes.
>Anybody want to hurt your vco (compensation of your choice) a little for a
>comparison? BTW when I said "then after a little minor drifting" maybe
>+-5hz .It was useable at the initial frequency within 60secs of being
>thermally slammed. I though that was pretty good. 

>-tg 

What I found out is that if you heat only selected components the results will be worse. In a real life situation the entire VCO board will usually be rather evenly heated, so I think it is pointless to heat or cool off just the expo converter. I tried putting a spotlight close to the board, to heat it. That caused more drift than the box test, both with and without tempco resistor.
Next I'm going to try connecting a 3000 ppm/C and a 3900 ppm/C tempco resistor in series or parallell. Currently I'm only using a 3000 ppm/C tempco, which undercompensate slightly. Using two tempcos is not a problem, as the SMD ones are so cheap.

/J?rgen





From chris at scp.de  Tue Jan 26 12:04:23 1999
From: chris at scp.de (Christian Hofmann)
Date: Tue, 26 Jan 1999 12:04:23 +0100
Subject: info on Panasonic BBD's found
In-Reply-To: <36AD35D9.9C2ADB1A@clara.net>
References: <36AD35D9.9C2ADB1A@clara.net>
Message-ID: <199901261104.MAA24270@dilbert.scp.de>

On Tue, 26 Jan 1999 03:26:17 +0000
Peter Blackett <dragonser at clara.net> wrote:

> Hi there,
> just found the following page with some details on Mn3xxx  series BBd
> delay ic's.
> http://www.mec.panasonic.co.jp/e-index_catalog.html
> hope this is usefull  !
> regards Peter 
> South London England
> 

Useful? I've been looking for those data sheets for ages!! Actually,
I've been to that site before, and found some brief references to BBDs,
but no PDFs. Well, some things do change...

Thanks-a-lot for that hint. Time to heat up the soldering iron :-)
Christian




From martin.czech at intermetall.de  Tue Jan 26 12:06:47 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 26 Jan 1999 12:06:47 +0100 (MET)
Subject: vco7c thermal results
Message-ID: <199901261106.MAA00195@window.intermetall.de>

Just a proposal:

The shoebox is ok.  Add a little air blower fan (you might have an old
one) and a resistor array/regulator and temp sensor as heater.  This way
it should be possible to heat the air in the shoe box quite evenly. This
way commercial temp test chambers work.

m.c.




From martin.czech at intermetall.de  Tue Jan 26 12:52:52 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Tue, 26 Jan 1999 12:52:52 +0100 (MET)
Subject: vco7c thermal results
Message-ID: <199901261152.MAA00544@window.intermetall.de>

> >And then Ta might change from 40C to 15C (in my living room).
> >
> well mc, your living room must have the sauna conversion..
> mine gets to 40dec c also, but not when i want it..
> 
No serious, Ta is temp ambience, in this case near to the pcb, you know
this for shure.  Last summer I had 28C air temperature. So it could well
be that larger modules with lots of consumption create an internal Ta
of 40 or even 50C. Tj (which is junction, or crystal temp), can easily
be 10C higher, depending on power dissipation and package.


A studio cicuit should work from 10C to 30C air temp,
which could be 15C to 45C Ta in the module, I think.


(I bought a second fan.  The problem is the fridge, it heats up my little
appartment, and also the oven, of course. I live in the basement floor,
so better keep the windows shut all day, it is so easy to climb into the
window for burglary. @ years ago the came in into my neighbour's... In the
winter I seldomly turn on the heating, only when I'm in and not sleeping,
this is not many hours.  So, without heating the temp drops to 13C, which
is ok, because it is better to have "fresh" air then suffer from dehydration
because of extreme heating. You get used to it. If I visit people with normal 
heating, I think I'm in the Kongo Delta...)

m.c. 
in the rooms of liquid sky




From Raoul.de.Vries at exact.nl  Tue Jan 26 13:18:37 1999
From: Raoul.de.Vries at exact.nl (Raoul.de.Vries at exact.nl)
Date: Tue, 26 Jan 1999 13:18:37 +0100
Subject: please remove
Message-ID: <C1256705.0044303B.00@nl000nt10.exact.nl>



sorry, list is getting too crowded for my work.





From cyborg0 at GlobalEyes.net  Tue Jan 26 14:21:24 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Tue, 26 Jan 1999 07:21:24 -0600
Subject: studio 440 stuff again
Message-ID: <36ADC154.408019B3@globaleyes.net>

Well, got another update.
The studio 440 now will load disks fairly regularly without crashing
(YEAAA!)
Furthermore it now will make noise, which can't be bad. :)

BUT, I *hope* its just cuz i dont have the manual, but for the LIFE of
me I cant seem to figgure out how the sequencer worx...Can anyone write
me up a little instruction on how to record a loop and play it back?
Please?

Another thingy is: I am looking at perhaps one of the UART sections
components being bad, and in reading the schematics, I came upon what I
thought was a good idea..

It seems as though the cem5530 (giant chip thingy) can dynamically send
stuff like PAN, PITCH, and LEVEL to the cem3389.
Well, I got to thinking.. ;) Wouldnt it be neat to be able to control
RESONANCE instead of PAN? I mean, who uses PAN anymore? Since the studio
440 has 8 outs, do it from yer mixing board already! 
Yes, PAN will now become REZ very shortly just by rerouting the pan pin
to the REZ pin on the CEM3389....Whats great about it is, the PAN
setting is set in memory in the patch..So, that means that whatever the
rez setting is at, it will save it! YEAH@! AND, you can record the
movements of the PAN pot too..Yummy..

OH, BTW, this thing makes every sample sound sooooo rich! I can see why
ppl love it so much.. Sonically, makes the akai seem so whimpy.. Nuttin
like 16khz grit over analog filters.

Rob



From patchell at teletrac.com  Tue Jan 26 16:43:09 1999
From: patchell at teletrac.com (Jim Patchell)
Date: Tue, 26 Jan 1999 07:43:09 -0800
Subject: PNP arrays
References: <3.0.1.32.19990125214412.009b3e10@mail.infomatch.com>
Message-ID: <36ADE28D.D7D75D3C@teletrac.com>

    According to the data sheet I got from Motorolla for the MPQ2907, there is no
spec for Vbe matching, which leads me to believe that it is just four transistor
chips bonded in one package.  Most likely they will be connected fairly well
thermally.  I was considering buying a batch and seeing if it was posible to
select them for having closely matched pairs.  Jameco has them listed in their
catalog for about $0.45 each in 100's.

    -Jim

Donald Johnson wrote:

> Future/Active here in Canada sell quad 2N2907(PNP)/2N2222(NPN) in 14 pin dips.
> They also have quad 2N3906/2N3904 in the same 14 pin dip package. The 2N
> prefix seems to be replaced with MPQ. (e.g. MPQ2907) I don't know if they
> merely 4 transistors packaged in a single dip, or if they are on a single
> chip, etc. I'll try to dig up some information. Anyone else seen or used them?
>
> don.
>
> ( (        don johnson        ) )
>  \ \                         / /
> ) ) ) donaldj at infomatch.com ( ( (
>  / /                        \ \
> ( (            -             ) )






From patchell at teletrac.com  Tue Jan 26 16:46:23 1999
From: patchell at teletrac.com (Jim Patchell)
Date: Tue, 26 Jan 1999 07:46:23 -0800
Subject: PNP arrays
References: <199901260829.JAA29687@window.intermetall.de>
Message-ID: <36ADE34F.47BD5238@teletrac.com>

    Another thing to consider is posibly using the PNP pair as a current
mirror, or using a matched PNP pair external to a CA3046 as a current mirror.

    -Jim

Martin Czech wrote:
 <snip>

> So it would certainly be better to use a pnp-pair with more performance,
> but the few parts that are on the market don't allow for chip heating...
> and that means that the thermal error will be much worse then the scaling
> error because of low hfe, we had just a mail about thermal results...
>
> m.c.






From Juergen.Haible at nbgm.siemens.de  Tue Jan 26 16:51:23 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 26 Jan 1999 16:51:23 +0100
Subject: AW: 5PDT/6PDT switches?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582012BF22B@nbgm336a.nbgm.siemens.de>

	>Just an option.  If you do find a reliable source on high quality
	>multi-pole toggles, please post it to the list!

I'm using these little relais in DIL package. For the HiFli Clone,
I wanted true bypass (unlike the original HiFli), so I was looking
for a 4p2t switch. Two 2p2t DIL relais turned out to be cheaper,
and I can also use a footswitch the bypass function now.

JH.




From merlin at ion.com.au  Tue Jan 26 17:06:35 1999
From: merlin at ion.com.au (Merlin Zener)
Date: Wed, 27 Jan 1999 02:06:35 +1000
Subject: Any disadvantages in mounting PCB's upside-down?
References: <Pine.3.89.9901220105.A28374-0100000@netcom9>
Message-ID: <36ADE80B.73108F0A@ion.com.au>

Brett Duggan wrote:
> 
> > Can any of you please tell me if there are any disadvantages in mounting
> PCB's upside-down?  


You'd have to be sure that dust and moisture didn't build up
on the board, particularly if there are high voltages involved.
I remember fixing several New Zealand made MOSFET power amps
where, over time, the dust etc would build up resulting in
sparks across tracks...

-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"



From merlin at ion.com.au  Tue Jan 26 17:06:42 1999
From: merlin at ion.com.au (Merlin Zener)
Date: Wed, 27 Jan 1999 02:06:42 +1000
Subject: 5PDT/6PDT switches?
References: <1.5.4.32.19970420042335.00cea3f8@popa.melbpc.org.au>
Message-ID: <36ADE812.DE23F8B5@ion.com.au>

Paul Perry wrote:
> 
> [...snip]
> 
> Now, a FOOT OPERATED 6PDT.. that WOULD be something!

simple. just get one of those Roland footswitches (flat,
square, plastic things) and mount 3 switches in it.


-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"



From edusilva at bahianet.com.br  Tue Jan 26 18:22:33 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Tue, 26 Jan 1999 15:22:33 -0200
Subject: PNP arrays
Message-ID: <199901270055.WAA01498@postman.bahianet.com.br>

> Speaking of transistor arrays... Does anyone know of a cheap transistor
> array with a good matched PNP pair? I haven't found one.
> 
> SV

How about SSM2220P? Only a pair, but I think it's enough.

Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil





From allan.houston at lineone.net  Tue Jan 26 19:32:20 1999
From: allan.houston at lineone.net (Allan)
Date: Tue, 26 Jan 1999 18:32:20 -0000
Subject: Filter Design
Message-ID: <000001be495a$356442c0$7de5abc3@default>

For my Synth(its a Uni. project), my lecturer has suggested these filters:

MF10
MF5
LMF100
LMF100C1
LTC1068C

Should I use any of these or are they not suitable for this purpose?
If not any suggestions for readily available alternatives?

Also How many filter banks should i use/are commonly used?  Do i need a
number of diffrent types i.e low,high and band pass?

Cheers

Allan




From cstecker at ovenguard.com  Tue Jan 26 21:19:45 1999
From: cstecker at ovenguard.com (Chris Stecker)
Date: Tue, 26 Jan 1999 12:19:45 -0800
Subject: "Warm-up time" for Buchla 400?
Message-ID: <v02110106b2d3d34e678a@[205.134.241.94]>

Hi there,

I've got a Buchla 400 that works pretty good except for one strange deal:
it needs to "warm up" before it will boot.   What I mean is that when I
first power it on, it's in its default non-working state (unbooted), but
asking it to boot from floppy, or even to run a RAM test (a procedure
stored in ROM OS memory) results in nothing.  Repeated attempts don't help.
After being left on for about 10 minutes, the machine will finally run a
RAM test, but still won't boot from floppy.  Finally, after "warming up"
for 15-20 minutes, it will load from floppy and run fine thereafter.  I can
turn it off, then back on, with no problems.  It's just that initial 20
minute period...

I've worked on several 400's, and this is the only one I've seen with this
particular problem.  There are, of course, no components that ought to need
warming up in the beast.  My thoughts are (1) something is loading one of
the supply voltages in a capacitative manner, and gets charged up in the 20
minute period (seems like a long time for that) or (2) something to do with
heat.

Anyway, I wonder if any of you had seen a problem like this before.  Thanks,

Chris Stecker





From magnus at analogue.org  Tue Jan 26 21:49:24 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 26 Jan 1999 21:49:24 +0100
Subject: vco7c thermal results
In-Reply-To: Your message of "Mon, 25 Jan 1999 16:25:44 -0500"
References: <199901252131.QAA18014@smtp3.mindspring.com>
Message-ID: <199901262049.VAA02425@mail2.it.kth.se>

>>>>> "t" == tomg  <vco at mindspring.com> writes:

 t> I did a few experiments for the fun of it. I set the vco at 440hz then
 t> sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
 t> about 60secs to recover to 440hz then after a little minor drifting
 t> stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
 t> in the middle of the 3046 for 30secs. The freq went down to 382hz again it
 t> took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
 t> got out the hair dryer full bore and max heat about 6" from the board for
 t> 30secs freq went down to 332hz and took about 5mins to fully recover.

Now, talking about spray freezing... a very dear friend of mine got
the experience that instead of "discovering" errors by spray-freezing
components (like possibly wacko EPROMs) he actually introduces new
errors. So, excess use for the spray can may be a good way to actually
kill a good chip. This is due to the thermical changes of physical
size and now that you only got a chip shrinked in one end you get a
lot of nice physical stress, which can develope small cracks and
dislocations. This can also happend to a transistor when you zap it
slightly, you get a "beta-degradation". In the transistor case it
migth be cured by heating it up under certain conditions, but it is
not recommended to do such things.

Cheers,
Magnus




From magnus at analogue.org  Tue Jan 26 22:09:03 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 26 Jan 1999 22:09:03 +0100
Subject: High-Speed Digital Design -Handbook of Black Magic"
In-Reply-To: Your message of "Tue, 26 Jan 1999 01:19:01 -0800"
References: <36AD8885.42E3@swipnet.se>
Message-ID: <199901262109.WAA02719@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:

 B> Magnus Danielson wrote:
 >> First I got one for myself, and then I bougth 4 for work and spread
 >> them over the hardware department (rather, sneaked them onto the table
 >> of people in deep need for it).
 >> 
 >> Cheers,
 >> Magnus

 B> Well done , thats the right thing to do ! :)

Not only that, today I learned the boys to place the resistors and
caps on the rigth end of the PCB traces with direct reference to said
book. Suddenly all the bit errors where gone and another round for the
PCB layout is comming up.

Finally they are starting to apprechiate what the book is about.

Let me tell you, the calculations to do right is not hard, the
analysis of the board when you don't do it is really non-obvious.

I got feedback from real life today, that was a nice change ;)

Cheers,
Magnus



From hbissell at ROBOTRON.com  Tue Jan 26 22:16:21 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Tue, 26 Jan 1999 16:16:21 -0500
Subject: Filter Design
Message-ID: <D74175EC1853D211BB7200A0C9E0C1190A3FA5@ROBOMAIL>

These are "switched capacitor" filters which are better suited to fixed
filter designs with very high roll-off slopes, most useful for
"anti-aliasing" filters in sampled data systems. You will need a filter
response from about 20Hz to about 20KHz. This is a 1000:1 range. If you take
the highest fundamental frequency (20Khz) times the clock rate (usually 50
or 100 times the highest frequency) you would need a clock frequency of 2MHz
at the high end, and 2KHz at the low end. So, you are very likely to hear
all sorts of clock breakthrough at the lower frequencies, as well as
aliasing from the higher harmonics of the input signal. You can't add an
input R/C pre-filter to prevent aliasing, and you can't add an output
post-filter that will work with the 2KHz clock rate and not be completly
overkill at the 2MHz clock rate. Bottom Line: Switched Capacitor filters are
not really musically useful.

Filters needed for Synthesis are: at least one Lowpass-Resonant filter with
a center frequency range of 1000:1 and resonance (Q) from less than 1 to
maybe several hundred. Slope is usually from 12db to 24db per octave.
Alternate choices would be a lowpass-bandpass-highpass or some combination
of the above. There are lots of filter designs to choose (copy) from. Try a
filter like the "Wasp" (a 12db state variable filter with high-low-bandpass
and notch responses) and tell your professor how interesting it is to use
logic ICs in a linear application), or the all time favorite "moog ladder
filter" a 24db lowpass-resonant filter, but add a twist like a second,
tapped output at the 12db point (I simulated this with a spice program and
it looks like it would be neat). But don't... don't use switched capacitor
filters for electronic music. Unless you want to demonstrate to your
professor that they SUCK !

You can find the schematics for lots of filters on the web, and the people
at DIY have almost all of them.
Happy Hunting: Harry

> -----Original Message-----
> From:	Allan [SMTP:allan.houston at lineone.net]
> Sent:	Tuesday, January 26, 1999 1:32 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Filter Design
> 
> For my Synth(its a Uni. project), my lecturer has suggested these filters:
> 
> MF10
> MF5
> LMF100
> LMF100C1
> LTC1068C
> 
> Should I use any of these or are they not suitable for this purpose?
> If not any suggestions for readily available alternatives?
> 
> Also How many filter banks should i use/are commonly used?  Do i need a
> number of diffrent types i.e low,high and band pass?
> 
> Cheers
> 
> Allan



From buchanan at qualcomm.com  Tue Jan 26 23:52:00 1999
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Tue, 26 Jan 1999 14:52:00 -0800
Subject: "Warm-up time" for Buchla 400?
In-Reply-To: <v02110106b2d3d34e678a@[205.134.241.94]>
Message-ID: <3.0.3.32.19990126145200.0164a100@mage.qualcomm.com>

At 12:19 PM 1/26/99 -0800, Chris Stecker wrote:
>Hi there,
>
>I've got a Buchla 400 that works pretty good except for one strange deal:
>it needs to "warm up" before it will boot.   What I mean is that when I

Hello,

Although I've never even seen a Buchla 400, I've worked on lots of other
equipment that has had similar symptoms.  It's often one of two things: 1)
Cold/old solder connection on board that makes contact once metal expands a
little bit.  2) Intermittent wire bond inside semiconductor package {IC or
Tranny}).  By far # 1 is the most common and we could never proove # 2 -
just hypothesized.

Either way, resoldering the circuit board (especially where components heat
up) frequently fixes # 1 or breaks # 2 the rest of the way so the bad part
can be traced down reliably.  You can also try flexing the circuit board
(gently!) or tapping on parts to track down the trouble area.

Just an idea,

Buck



From uzs159 at uni-bonn.de  Wed Jan 27 00:45:32 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 27 Jan 1999 00:45:32 +0100
Subject: A few thoughts on heat tests and heaters
Message-ID: <3.0.5.32.19990127004532.009107a0@ibm.rhrz.uni-bonn.de>

Hi, 

with the recent discussion on the heater stabilization, 
and on how to test it, I have some comments:

A few months ago I did wan't to test a thermo compensation circuit.
(the circuit has been discussed here before, so all that is in the archives)

I did the heat gun, and freeze spray tests and after I had tried it, I had
a few concerns about the results.
There is a temperature stable point in every VCOs expo convertor, when
dVbe=0 then there is nothing to drift with temperature. This depends of
course on the chosen frequency at which the test is performed. To make any
use of the measurement, one would have at least have to measure two
frequencies, one below and one above the temperature stable point. 

Then obviously there is the problem of temperature gradients, when using
the iron to heat up the chip, nothing makes shure that the heat is
distributed evenly on the package and the chip. 
The second problem I encountered was when using freeze spray, because there
will be water condensing on the circuit which causes leakage currents.
(I now use it only in TV repairs, and hope there won't be any sparks :) 

Finally a few thoughts on the ovenized convertors (and why I don't use these):

It is often repeated that this circuit will draw much current. Me too ;)
But one thing that isn't often mentioned is that some transistor parameters
degrade with increasing temperature. For example the leakage current!
The leakage is interesting only in VCOs that have the cap to the supply
because 
then the sinking transistor will have a rather large voltage across it. (In
VCOs where the current flows from a virtual ground this is not an issue.)

Another thing makes this even worse: the heater can't make the chip cooler
than it is. So if you choose your heater temperature too low, the
regulation won't work at temperatures above that, and if you make it too
high the performance of the transistors may degrade.

Bye
 Rene


             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From adaaxs at erols.com  Wed Jan 27 00:58:10 1999
From: adaaxs at erols.com (J.G. Wong)
Date: Wed, 27 Jan 1999 00:58:10 +0100
Subject: EMS Help May be OT for some of you.
Message-ID: <36AE5687.19480AFD@erols.com>

Hi All,

    I am very sorry for crossposting this, but I consider these
essential places with people with similar concerns. and decent folks for
the most part.

    Aside from having a Mellotron soon to go to the shop and needing
help on building a Moog VCA and a KS clone I have a real problem.

    My EMS Synthi aks KS keyboard is not functioning properly.  I get
low note and then another note an octave or so higher on every pressure
point above.  I know how to use it so please no brush offs. . The
sequencer functions but there is nothing to store but two notes.  I
needed this unit for a project  I know that practical applications of
this part of that synth is rare.  Rare day today !

    Robin Wood has told me there are no sanctioned US support centers
and these things are not made anymore, they are rare and precious.

    I have talked to prolific posters an all of these lists and know
that there are many of you who have and use and need these machines. Who
can I trust to fix this without sending it to the UK for 26 weeks.

    If any of you, lurkers and posters can help pleasecontact me.

Thanks

G. Wong  (Fiveman)




From jlarryh at iquest.net  Wed Jan 27 05:04:48 1999
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Tue, 26 Jan 1999 22:04:48 -0600
Subject: A source for Joysticks
Message-ID: <199901270259.DAA26031@mailhost.bpa.nl>

I remember a while back some people here were looking for Joysticks.  I
found this today and I am passing this along for information to those that
may be interested:

All Electronics   P.O. Box 567,  Van Nuys, CA  91408-0567
1-800-826-5432

Direct quote from catalog:

"CH products high quality joystick assembly with solid spring-return
centering and snap action pushbutton on joystick tip.  Two 5K ohm pots are
controlled by the stick's X-Y axis.  The push button is connected to 10"
teflon coated leads.  Interior mechanical parts are nylon.  Black plastic
enclosure is 2" x 2" x 1.45" deep.  Black 1.68" diameter bezel surrounds
joystick.  Metal joystick with plastic handle is 3" long.  Ideal for RC
models, robotics, and games."
Cat # JS-3  $5.75 each.

This is a "new" item in the catalog.  One thing I have learned about All
Electronics is buy all you want now if you find something, as they may not
have it later.  I have found the large diameter heavy duty Switchcraft 1/4"
phone plugs in the catalog on occasion for an excellent price.  However,
they rarely have them.  return policy is no authorization nor reason
required if returned as re-sellable. 

The photo looks like a fairly well sealed lower unit except the pots appear
on the outside, so I suspect that one might change them for a different
value.  It is difficult to tell if the "metal" part of the joystick extends
up into the plastic handle or not.  Nice looking bezel.

All Electronics has no minimum order.  However, all orders are charged
$5.00 flat rate S & H to the 48 continental US states.  They do offer
foreign shipping but quote no rates.

Larry Hendry




From martin.czech at intermetall.de  Wed Jan 27 08:37:00 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 27 Jan 1999 08:37:00 +0100 (MET)
Subject: vco7c thermal results
Message-ID: <199901270737.IAA07879@window.intermetall.de>

> Now, talking about spray freezing... a very dear friend of mine got
> the experience that instead of "discovering" errors by spray-freezing
> components (like possibly wacko EPROMs) he actually introduces new
> errors. So, excess use for the spray can may be a good way to actually
SNIPPED

We used freeze spray all day, to detect timing faults.
The No. 1 problem is condensed water, or ice, which will lead
to leakage or even temporarily disfunction, until the part
has dryed again.
Now we have a thermo stream with dryed air.

I never had problems with thermal/mechanical stress on chips,
but there is certainly a socket problem if you heat up the
thermostream from -40C to 120C, which takes about 30 seconds.

Our chips/packages are tested for thermal/mechanical stress imunity,
via temperature shock/pressure coocker. If you use the right plastic
material, this stress is not harmfull. 

But if your chip has a very odd aspect ratio and you use the wrong 
package plastic you'll shure crack the chip, that's certainly true.

m.c.   




From martin.czech at intermetall.de  Wed Jan 27 08:48:33 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 27 Jan 1999 08:48:33 +0100 (MET)
Subject: A few thoughts on heat tests and heaters
Message-ID: <199901270748.IAA07906@window.intermetall.de>


> I did the heat gun, and freeze spray tests and after I had tried it, I had
> a few concerns about the results.
> There is a temperature stable point in every VCOs expo convertor, when
> dVbe=0 then there is nothing to drift with temperature. This depends of
> course on the chosen frequency at which the test is performed. To make any
> use of the measurement, one would have at least have to measure two
> frequencies, one below and one above the temperature stable point. 
> 

I think that the most  obvious thermal dependency occurs at the highest
possible frequency? So it would be good to tune the osc to, say 17kHz
and then do the heating.


> Then obviously there is the problem of temperature gradients, when using
> the iron to heat up the chip, nothing makes shure that the heat is
> distributed evenly on the package and the chip. 

Right. The system should have time to settle down at the new temperature.
You don't need the ability to cycle temperstures in practice, just settling on 
other conditions. 

> The second problem I encountered was when using freeze spray, because there
> will be water condensing on the circuit which causes leakage currents.

Right. Would be a very bad thing, since little currents are involved.
Better heat only.

> But one thing that isn't often mentioned is that some transistor parameters
> degrade with increasing temperature. For example the leakage current!
> The leakage is interesting only in VCOs that have the cap to the supply
> because 
> then the sinking transistor will have a rather large voltage across it. (In
> VCOs where the current flows from a virtual ground this is not an issue.)
> 
> Another thing makes this even worse: the heater can't make the chip cooler
> than it is. So if you choose your heater temperature too low, the
> regulation won't work at temperatures above that, and if you make it too
> high the performance of the transistors may degrade.
> 
 
The heater tranny should not leave the recommended operation area for shure!
There should allways be some measures to enshure that this can't happen,
even if the regulator freaks out. If you are in recommended area, the array
does not degrade (irreversibly), but parameters change due to temperature,
like you say, leakage, or hfe etc.

If you want to let the thing oscillate at very low currents you need some kind
of leakage compensation anyway.

m.c. 




From djblue at asu.edu  Wed Jan 27 09:25:25 1999
From: djblue at asu.edu (Reverend bluE)
Date: Wed, 27 Jan 1999 01:25:25 -0700 (MST)
Subject: need help making a keyboard (and my vco is stupid.. or maybe I'm
 stupid)
Message-ID: <Pine.GSO.3.96.990127011053.6844E-100000@general1.asu.edu>


I just bought a cheap-o synth keyboard (has two voices on a digital chip) and
I want to make it into a controller for my modular.  I've opened it up, and
has a single contact switch per key made of traces wiggling between each
other (they look like if you meshed your fingers from both hand together if
you know what I mean) and it has some little diode type things on there (they
are very small and kinda clear and kinda orangish looking).  Also I think
there are about 6-8 wires coming from the key contact PCB to the sound chip.

I've been searching all the usual sites, and I know I had found the
instructions for doing this a few weeks ago, but I can't find it now. 

any help?

on a different note (or lack there-of) I finished my second VCO 
(Maxx2 VCO-2D except I swapped the 2N3904 tranny pair for a MAT-02)
and it wouldn't work at first, then I realized that I had the +/- power lines
reversed, so I switched them and it worked, but barely.  On square output, the
fine tune barely worked, and I could only get sound with the PW pretty much
centered.  and the turning "sweep" for the PW pot was very limited.  I then
noticed that I had the PW pot and the fine tune pot switched (10k and 100k),
and that I had  my jacks hooked up backwards (ground to tip) so I swapped
those and now it won't work at all.  

again... any help?
-ben


I'd just like to say that I would have shot myself if not for this list...  
well, either shot myself or threw away my synth "projects"... 
yeah, that sounds safer I suppose.





From aschrock at cs.brandeis.edu  Wed Jan 27 10:19:33 1999
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 27 Jan 1999 04:19:33 -0500 (EST)
Subject: need help making a keyboard (and my vco is stupid.. or maybe I'm stupid)
In-Reply-To: <Pine.GSO.3.96.990127011053.6844E-100000@general1.asu.edu>
Message-ID: <Pine.SGI.3.95.990127041353.27835A-100000@amber.cs.brandeis.edu>

On Wed, 27 Jan 1999, Reverend bluE wrote:
> on a different note (or lack there-of) I finished my second VCO 
> (Maxx2 VCO-2D except I swapped the 2N3904 tranny pair for a MAT-02)
> and it wouldn't work at first, then I realized that I had the +/- power lines
> reversed, so I switched them and it worked, but barely.  On square output, the
> fine tune barely worked, and I could only get sound with the PW pretty much
> centered.  and the turning "sweep" for the PW pot was very limited.  I then
> noticed that I had the PW pot and the fine tune pot switched (10k and 100k),
> and that I had  my jacks hooked up backwards (ground to tip) so I swapped
> those and now it won't work at all.  

No, I think this is normal. My VCO-2's exhibit this same type of
pulsewidth weirdness... very small range of initial PW tuning, and then
harder to tune again once you add PWM in. I'm going to play with
resistance values (that's really all that's the problem, the PWM sounds
great otherwise). I'll post results later, I should have done this a month
ago.. grumble.. no time. 

I put 10-turn bournes pots for my pitch tuning, but just cuz I happened to
find them laying around. No problems with 'em, the pitch is fine. The
VCO's scale fine for me as well, but you didn't mention that. 

Try going back and rechecking your work. You won't get anything to work
past 1am ;) I've had many a project saved cuz I gave up and went back the
next day. 

Andrew

-| Andrew Schrock | aschrock at cs.brandeis.edu |-






From MHELIN at tne01.ntc.nokia.com  Wed Jan 27 11:45:49 1999
From: MHELIN at tne01.ntc.nokia.com (Mikko Helin)
Date: Wed, 27 Jan 1999 12:45:49 +0200
Subject: Filter Design
Message-ID: <990127124549.5301ef20@tnclus.ntc.nokia.com>


At 06:32 PM 26/01/99 -0000, allan.houston wrote:
>For my Synth(its a Uni. project), my lecturer has suggested these filters:
>
>MF10
>MF5
>LMF100
>LMF100C1
>LTC1068C
>
Don't know about these, but I was reading some old issue
of EW this morning (while waiting the car battery charging-
it's not so warm here now, -51 degree Celsius in northern
Finland this morning, -22 here where I live), and there was 
a schematic of a filter built around some Linear Technology 
filter chip. Don't have the model number in my mind yet
(LT1256 or something like it), but it was not a swiched cap 
filter (think I), there was a VC input, no clock inputs.
If you can get the required clock, why not to try a switched
cap filter, somthing like LTC1059 or LTC 1060 (=MF10).

-Mikko





From mmcintos at ball.com  Wed Jan 27 18:24:42 1999
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Wed, 27 Jan 1999 10:24:42 -0700
Subject: XR2207 and XR2209 VCO chips
Message-ID: <09DB74475204D1119C8200805F19D00302E20BFA@aeromsg1.ball.com>

Ok all,

Can you tell me why the XR2207 or XR2209 VCO chip can not be used easily as
a basis for a VCO?  I looked at the data specs and it says the have a sweep
range of 1000:1, minimum.  Wouldn't that just cover the range of human
hearing (20Hz to 20KHz)?  Lowest frequency 0.01Hz - Highest frequency 1MHz.

Links:

http://www.exar.com/products/xr2207.html
http://www.exar.com/products/xr2209.html


Malcolm



From cyborg0 at GlobalEyes.net  Wed Jan 27 20:11:31 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Wed, 27 Jan 1999 13:11:31 -0600
Subject: A few thoughts on heat tests and heaters
References: <199901270748.IAA07906@window.intermetall.de>
Message-ID: <36AF64E3.C1C86818@globaleyes.net>

Martin Czech wrote:
> 
> > I d
> > The second problem I encountered was when using freeze spray, because there
> > will be water condensing on the circuit which causes leakage currents.
> 
> Right. Would be a very bad thing, since little currents are involved.
> Better heat only.

I saw a schematic on a radar transmitter for a air traffic control
tower.. it had a seperate schematic for nitrogen lines.. nitrogen is the
only way to cool without condensation supposedly..
rob



From buchanan at qualcomm.com  Wed Jan 27 20:18:52 1999
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Wed, 27 Jan 1999 11:18:52 -0800
Subject: XR2207 and XR2209 VCO chips
In-Reply-To: <09DB74475204D1119C8200805F19D00302E20BFA@aeromsg1.ball.com
 >
Message-ID: <3.0.3.32.19990127111852.00c1e760@mage.qualcomm.com>

Hi Malcolm,

First off, as far as I know, the 2207 and 2209 have become somewhat
difficult to find.  At least most of the places I used to see them don't
have them anymore.  The XR2206 is still popular and probably better than
the other two anyway.

Secondly, they have linear frequency sweeps.  So 1V/oct. operation is out
(this is considered the biggest stumbling block).  

That doesn't, however, mean they arent good for LFOs and abstract music
purposes (I've got a couple older modules with these chips in them since my
main focus is weird sounds).  Also cool about the XR2206 is the AM input! 

But for an IC oscillator solution, I would definately suggest the CEM3374.
You can get this from Synthesis Technologies.  It's expensive (~15$) but
worth it considering the time you save - it performs quite well with expo
and linear sweeps I think closer to the order of 100,000:1.  Also a
tempco'd reference voltage out if you go to the trouble of putting it to
use (tho my 3374 oscs are pretty darn stable w/o tempco).

Take it easy,

Buck

At 10:24 AM 1/27/99 -0700, you wrote:
>Ok all,
>
>Can you tell me why the XR2207 or XR2209 VCO chip can not be used easily as
>a basis for a VCO?  I looked at the data specs and it says the have a sweep
>range of 1000:1, minimum.  Wouldn't that just cover the range of human
>hearing (20Hz to 20KHz)?  Lowest frequency 0.01Hz - Highest frequency 1MHz.
>
>Links:
>
>http://www.exar.com/products/xr2207.html
>http://www.exar.com/products/xr2209.html
>
>
>Malcolm
>
>



From vco at mindspring.com  Wed Jan 27 20:21:05 1999
From: vco at mindspring.com (tomg)
Date: Wed, 27 Jan 1999 14:21:05 -0500
Subject: Mad Mouse PCBs
Message-ID: <199901271927.OAA26527@smtp2.mindspring.com>

The PCBs are here! Very nice... I'm putting the first one together
now. I hope to ship them by Friday. I will email you as soon as yours
ships.
-tg
--------------------------------------------------------------------------
Mad Mouse - PC Board - Analog For Everybody
http://www.mindspring.com/~vco/madm/mm_order.html
--------------------------------------------------------------------------



From patchell at teletrac.com  Wed Jan 27 21:07:47 1999
From: patchell at teletrac.com (Jim Patchell)
Date: Wed, 27 Jan 1999 12:07:47 -0800
Subject: XR2207 and XR2209 VCO chips
References: <09DB74475204D1119C8200805F19D00302E20BFA@aeromsg1.ball.com>
Message-ID: <36AF7213.91FB1C50@teletrac.com>

    I tried to use these a long time ago (1977), and they are just not very
linear.  Frequency vs. Control Current is very bumpy, making the musically not
useful.  They are OK so long as you are not going to use them for a pitch
source.

    Jim

McIntosh, Malcolm wrote:

> Ok all,
>
> Can you tell me why the XR2207 or XR2209 VCO chip can not be used easily as
> a basis for a VCO?  I looked at the data specs and it says the have a sweep
> range of 1000:1, minimum.  Wouldn't that just cover the range of human
> hearing (20Hz to 20KHz)?  Lowest frequency 0.01Hz - Highest frequency 1MHz.
>
> Links:
>
> http://www.exar.com/products/xr2207.html
> http://www.exar.com/products/xr2209.html
>
> Malcolm






From b.layer at vikingelectronics.com  Wed Jan 27 21:42:41 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 27 Jan 1999 14:42:41 -0600
Subject: A few thoughts on heat tests and heaters
In-Reply-To: <36AF64E3.C1C86818@globaleyes.net>
References: <199901270748.IAA07906@window.intermetall.de>
Message-ID: <3.0.6.32.19990127144241.007e19b0@192.168.210.18>

Hi All,

>I saw a schematic on a radar transmitter for a air traffic control
>tower.. it had a seperate schematic for nitrogen lines.. nitrogen is the
>only way to cool without condensation supposedly..

So was that an immersion system then? A pure liquid nitrogen bath would
certainly be anhydrous... Or was the nitrogen used in another manner?




Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

 



From uzs159 at uni-bonn.de  Wed Jan 27 23:45:14 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 27 Jan 1999 23:45:14 +0100
Subject: XR2207 and XR2209 VCO chips
In-Reply-To: <3.0.3.32.19990127111852.00c1e760@mage.qualcomm.com>
References: <09DB74475204D1119C8200805F19D00302E20BFA@aeromsg1.ball.com >
Message-ID: <3.0.5.32.19990127234514.0079c8d0@ibm.rhrz.uni-bonn.de>

At 11:18 27.01.99 -0800, you wrote:

>Secondly, they have linear frequency sweeps.  So 1V/oct. operation is out
>(this is considered the biggest stumbling block).

The same is said for the LM566 (tri, square), but there are ways.
I don't know exactly for the 2206, but it could be done similar:

The pin for the timing resistor really senses the current into (or out of)
that pin, (i.e. the pin is held internally at some voltage and the current
flows to ground, or the control voltage) so it is misusable as a current
input, with the usual expo convertors.

See http://www.uni-bonn.de/~uzs159/vco_566.html 
for an example.

It *may* work similarly for the 2206, when pin 9 is left open and a current
sinking expo convertor is connected to pin 8. pin 8 is held at 3V above
ground. I have not tried it, but If I had some 2206s around I'd certainly
try it. I did build the circuit on my website however, and the sweep range
is more than sufficient (app. 1:10000 !) though the datasheet claims only
1:10, but this figure is only for voltage control in the normal
applications, and with a resistor as current source!
This VCO did track pretty good, for such a cheap thing.

Bye
 Rene








I could imagine that similar sweep ranges can be archeived with the 2206,
too. 


             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From varner at k-online.com  Thu Jan 28 01:37:50 1999
From: varner at k-online.com (Steve Varner)
Date: Wed, 27 Jan 1999 16:37:50 -0800
Subject: vco7c thermal results
References: <199901252131.QAA18014@smtp3.mindspring.com>
Message-ID: <36AFB15A.1FA18939@k-online.com>

...Now put it in the oven on broil for 3 hours...   ;-)

tomg wrote:

> I did a few experiments for the fun of it. I set the vco at 440hz then
> sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
> about 60secs to recover to 440hz then after a little minor drifting
> stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
> in the middle of the 3046 for 30secs. The freq went down to 382hz again it
> took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
> got out the hair dryer full bore and max heat about 6" from the board for
> 30secs freq went down to 332hz and took about 5mins to fully recover.
>
> -tg
> --------------------------------------------------------------------------
> Mad Mouse - PC Board - Analog For Everybody
> http://www.mindspring.com/~vco/madm/mm_order.html
> --------------------------------------------------------------------------






From peri at nolo.com  Thu Jan 28 01:45:29 1999
From: peri at nolo.com (Peri Pakroo)
Date: Wed, 27 Jan 1999 16:45:29 -0800
Subject: roland sh-3a question
Message-ID: <fc.004c55c000179741004c55c000179741.179743@nolo.com>

I'm working on a friend's sh-3A, and have most of it working, except the
vco output. I have a schematic from Roland, and I can trace the key
voltage to the output of an op amp on the vco board, configured as a unity
gain voltage follower. After that, I get lost. There is a matched
transistor pair that gets the cv, which can be altered by adjusting the
vco width and frequency pots or plugging in a vco pedal control. This pair
eventually feeds a small board plugged into the vco board, and it is my
guess that its output is a pulse that drives the LM3216 chip--the latter
looks like an analog frequency divider that sends the 4', 8', 16' and 32'
octaves to the vco octave sliders. 

I'm not well-versed in discrete circuitry, so I'm not sure which
components comprise the actual oscillator at this stage of the vco board.
Can anyone with a knowledge of the sh-3 circuitry help me trace through
this stage?  BTW, I called National Semi and Sanyo, but they don't even
show the LM3216 as a discontinued chip. I thought knowing the specs for
the input to this chip would help me trace the vco circuitry preceding it.
Is there any source of info on this chip, and possibly a supplier for a
replacement in case I need to try a new one?





From varner at k-online.com  Thu Jan 28 02:08:29 1999
From: varner at k-online.com (Steve Varner)
Date: Wed, 27 Jan 1999 17:08:29 -0800
Subject: Expo conv. heater (tomg et al.)
Message-ID: <36AFB888.FE8F09A7@k-online.com>

I haven't built a discrete VCO yet (just CEM chips in a kit VCO). I want
to build a 3046/thermostat circuit, but I have a few questions.

1. Do you really need a separate power source for the heater part?
That's a real pain in the rear. You mentioned regulators and I've seen
separate supplies mentioned on the web... so that's why I want to know.

2. Barry Klein suggested putting the 3046 under a styrofoam cover to
isolate the chip from heat loss or gain - sort of a chip calorimeter.
Has anyone done this?

3. How do you know where to set the temperature trim on the thermostat?
I mean, how do you know where to set the temperature and how do you
measure a silicon chip's temperature accurately anyway? Not having the
temp too high or low was discussed, so this is important.

PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
Circle you might not worry so much about temperature   ;-)

SV




From dave.halliday at greymatter.com  Thu Jan 28 07:02:22 1999
From: dave.halliday at greymatter.com (Dave Halliday)
Date: Thu, 28 Jan 1999 06:02:22 GMT
Subject: A few thoughts on heat tests and heaters
Message-ID: <9901272255551114@greymatter.com>

>>I saw a schematic on a radar transmitter for a air traffic control
>>tower.. it had a seperate schematic for nitrogen lines.. nitrogen is the
>>only way to cool without condensation supposedly..
>      
>     So was that an immersion system then? A pure liquid nitrogen bath would
>     certainly be anhydrous... Or was the nitrogen used in another manner?



With high-power radar, it is better to use physical waveguides than 
coaxial cable.  Waveguides are sealed metal channels whose physical 
dimentions are the same as one wavelength of the RF being carried - 
makes for a very low loss situation.

Only problem is that condensation kills the efficiency.  The 
waveguides are filled with pressurised Nitrogen ( a PSI or two above 
ambient ) and baked - silica gel removes the moisture and a pony 
bottle of N2 gas keeps any pinhole leaks from causing problems - 
positive pressure...




Obligatory audio information:

During WW2, the frequencies of RADAR were much lower and the
wavelength for the waves were about the same as the wavelengths
of sound waves in air.  There was a line of loudspeakers ( Karlsen? )
developed after WW2 that essentially took broadband RF antenna
designs and tweaked the impedences a bit to match a physical speaker
instead of an RF waveguide.

Very very high effeciency.  Frequency response was not linear but 
nothing else was at that time either so it didn't matter.





--- Via Silver Xpress V4.4 [Reg]



From synth1 at airmail.net  Thu Jan 28 07:08:54 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Thu, 28 Jan 1999 00:08:54 -0600
Subject: New MOTM info on site
Message-ID: <002801be4a84$b0b764e0$7969fea9@p400>

New MOTM modular info can be found at:

www.synthtech.com/motm

Also check the NEWS link for future module schedules.

Paul Schreiber
Synthesis Technology





From martin.czech at intermetall.de  Thu Jan 28 08:08:06 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 28 Jan 1999 08:08:06 +0100 (MET)
Subject: XR2207 and XR2209 VCO chips
Message-ID: <199901280708.IAA16280@window.intermetall.de>


> have them anymore.  The XR2206 is still popular and probably better than
> the other two anyway.
> 
> Secondly, they have linear frequency sweeps.  So 1V/oct. operation is out
> (this is considered the biggest stumbling block).  
> 

partly true. I remember building an expo controlled LFO with XR2206.
It is current controlled, so you can use a normal expo converter.

The XR2206 has a sine wave output with the lowest distortion (compared to
MAX083 or Harris chips). OTOH you can't have tri and sin at the same time.

I don't think I would use it today, a discrete matched sine converter
can yield much better results, and a tri oscillator can also be made
discrete with very good results (look at CA3080 app. notes).

m.c.




From jorgen.bergfors at idg.se  Thu Jan 28 08:37:05 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Thu, 28 Jan 1999 8:37:05 +0100
Subject: Expo conv. heater (tomg et al.)
Message-ID: <TFSANXAF@idg.se>

>1. Do you really need a separate power source for the heater part?
That's a real pain in the rear. You mentioned regulators and I've seen
separate supplies mentioned on the web... so that's why I want to know.

No, you don't need that, why would you? I have the Doepfer PMS quad VCO with one heater per VCO. It runs off the normal +15V supply.

>2. Barry Klein suggested putting the 3046 under a styrofoam cover to
isolate the chip from heat loss or gain - sort of a chip calorimeter.
Has anyone done this?

Not me.

>3. How do you know where to set the temperature trim on the thermostat?
I mean, how do you know where to set the temperature and how do you
measure a silicon chip's temperature accurately anyway? Not having the
temp too high or low was discussed, so this is important.

The PMS doesn't have adjustable temperature, so I didn't have to be bothered.





From zzynt at swipnet.se  Thu Jan 28 10:45:06 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 28 Jan 1999 01:45:06 -0800
Subject: XR2207 and XR2209 VCO chips
References: <09DB74475204D1119C8200805F19D00302E20BFA@aeromsg1.ball.com > <3.0.5.32.19990127234514.0079c8d0@ibm.rhrz.uni-bonn.de>
Message-ID: <36B031A2.4657@swipnet.se>

Rene Schmitz wrote:
> 
> At 11:18 27.01.99 -0800, you wrote:
> 
> >Secondly, they have linear frequency sweeps.  So 1V/oct. operation is out
> >(this is considered the biggest stumbling block).
> 
> The same is said for the LM566 (tri, square), but there are ways.
> I don't know exactly for the 2206, but it could be done similar:
> 
> The pin for the timing resistor really senses the current into (or out of)
> that pin, (i.e. the pin is held internally at some voltage and the current
> flows to ground, or the control voltage) so it is misusable as a current
> input, with the usual expo convertors.
> 
> See http://www.uni-bonn.de/~uzs159/vco_566.html
> for an example.
> 
> It *may* work similarly for the 2206, when pin 9 is left open and a current
> sinking expo convertor is connected to pin 8. pin 8 is held at 3V above
> ground. I have not tried it, but If I had some 2206s around I'd certainly
> try it. I did build the circuit on my website however, and the sweep range
> is more than sufficient (app. 1:10000 !) though the datasheet claims only
> 1:10, but this figure is only for voltage control in the normal
> applications, and with a resistor as current source!
> This VCO did track pretty good, for such a cheap thing.
> 

This is the same thing that you can do with the 4046 Vco, using
just a odinary expoconverter as Magnus once talked about some time ago!

But the 4046 is a current out device!

Any linearity specs for the 566?
How about the 567 PLL? any one tried that one?

BJ



From vco at mindspring.com  Thu Jan 28 10:51:30 1999
From: vco at mindspring.com (tomg)
Date: Thu, 28 Jan 1999 04:51:30 -0500
Subject: Expo conv. heater (tomg et al.)
Message-ID: <199901281002.FAA28732@smtp2.mindspring.com>



----------
> From: Steve Varner <varner at k-online.com>
> To: synth-diy <synth-diy at mailhost.bpa.nl>
> Subject: Expo conv. heater (tomg et al.)
> Date: Wednesday, January 27, 1999 8:08 PM
> 
> I haven't built a discrete VCO yet (just CEM chips in a kit VCO). I want
> to build a 3046/thermostat circuit, but I have a few questions.
> 
> 1. Do you really need a separate power source for the heater part?
> That's a real pain in the rear. You mentioned regulators and I've seen
> separate supplies mentioned on the web... so that's why I want to know.

No. But you have to beef up the one you intend to use a little. A fair
sized set of heat sinks for the regulators would be good.

> 2. Barry Klein suggested putting the 3046 under a styrofoam cover to
> isolate the chip from heat loss or gain - sort of a chip calorimeter.
> Has anyone done this?

Not me, but Berry is a pretty bright guy. Seems like it would be a little
odd though, kinda like a 3046 happy meal or something. 

> 3. How do you know where to set the temperature trim on the thermostat?
> I mean, how do you know where to set the temperature and how do you
> measure a silicon chip's temperature accurately anyway? Not having the
> temp too high or low was discussed, so this is important.

If it's too hot to keep your finger on it, It's too hot. Nice and warm is
the ticket, if you are just using one 3046 like I did in the vco7c. If you
intend to use one for each vco then the idle current needs to be the same
for both chips.   

> PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
> Circle you might not worry so much about temperature   ;-)

I'm a guitar player. A little drift in my tuning doesn't bother me at all!
I'm just glad I don't usually have to worry about trying to keep  6 of them
right.

-tg




From pfperry at melbpc.org.au  Thu Jan 28 12:32:42 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 28 Jan 1999 22:32:42 +1100
Subject: Expo conv. heater (tomg et al.)
Message-ID: <1.5.4.32.19990128113242.00d18be0@popa.melbpc.org.au>


>>3. How do you know where to set the temperature trim on the thermostat?
>I mean, how do you know where to set the temperature and how do you
>measure a silicon chip's temperature accurately anyway? Not having the
>temp too high or low was discussed, so this is important.
>
The word of God (Jim Williams):
"Q2's base-emitter junction senses array temperature" but read the National
 app notes for the full story.. no shortcuts on this one.

paul perry frostwave P/l Melbourne Australia




From martin.czech at intermetall.de  Thu Jan 28 12:43:46 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 28 Jan 1999 12:43:46 +0100 (MET)
Subject: Expo conv. heater (tomg et al.)
Message-ID: <199901281143.MAA17584@window.intermetall.de>

> 
> > 2. Barry Klein suggested putting the 3046 under a styrofoam cover to
> > isolate the chip from heat loss or gain - sort of a chip calorimeter.
> > Has anyone done this?
> 
> Not me, but Berry is a pretty bright guy. Seems like it would be a little
> odd though, kinda like a 3046 happy meal or something. 

Not odd. Makes sense.

You can't make the regulation loop as fast as you want, because of
temperature diff equation time lag, this would mean loop oscillation.
But you can damp external influences via isolation. This way the loop
is fast enough.

And:

You can reduce the total chip power consumption by isolation.
As I said earlier, heating is nice, but keep inside SOA!
Too much current will lead to migration und junction degradation,
and maybe also to second breakdown. That would be fatal.
The overall power consumption is lower (somebody complained because
he feared that the lights would go dim if the heater starts ;->).
 
> 
> > 3. How do you know where to set the temperature trim on the thermostat?
> > I mean, how do you know where to set the temperature and how do you
> > measure a silicon chip's temperature accurately anyway? Not having the
> > temp too high or low was discussed, so this is important.
> 

Test No 1

Build the temp sense circuit. I think it is a current source, the
part of the chip that does the sensing (one tranny as diode) and maybe
some sense amp.  Take a discrete diode and use it as dummy temp sensor.
Take a thermometer and prepare a glas of water with the same temperature
as the air. Measure Udiode in air.  Drop the diode in the water. Measure
again. If there is any significant difference it means bad temperature
of the water (check again or wait longer), or leakage current in the
water. In the later case use oil (kitchen) or clean water for automobile
battery. Now the leakage should be gone.

This way you have now prooven a large heat capacitance fluid without
leakage.


Test No 2

Now exchange the diode with the real chip.  Heat the medium to the wanted
temperature. Dip the IC, wait until settling down, and measure.

Now you know what voltage the sens amp will give for your wanted
temperature.  The trim voltage has to be of exactly this value for a
good PI regulator that will have no residual error.


Sounds stupid?

No!

We measure our Hall sensors in the lab exactly this way. Fluids have
better thermal contact and larger heat capacity. Heating with air is only
second choice.  Of course we use special oil, but I translated that to
home use. No poison.  

(I don't know if normal water will be ok, in the USA they are
bacteriophobic (sp?)  and put tons of Cl into the water, you can't drink
it any more. We don't have that much here, and nobody is harmed).


Of course I know I=Is*(exp{U/Ut}-1), the problem is that Is is not defined.
Varies from piece to piece and also with temp, but one does not know excactly
how with a specific chip. Better measure.

m.c. 




From zzynt at swipnet.se  Thu Jan 28 13:33:58 1999
From: zzynt at swipnet.se (BJ)
Date: Thu, 28 Jan 1999 04:33:58 -0800
Subject: Expo conv. heater (tomg et al.)
References: <36AFB888.FE8F09A7@k-online.com>
Message-ID: <36B05936.1CF1@swipnet.se>

Steve Varner wrote:
> 
> I haven't built a discrete VCO yet (just CEM chips in a kit VCO). I want
> to build a 3046/thermostat circuit, but I have a few questions.
> 
> 1. Do you really need a separate power source for the heater part?
> That's a real pain in the rear. You mentioned regulators and I've seen
> separate supplies mentioned on the web... so that's why I want to know.
> 
> 2. Barry Klein suggested putting the 3046 under a styrofoam cover to
> isolate the chip from heat loss or gain - sort of a chip calorimeter.
> Has anyone done this?
> 
> 3. How do you know where to set the temperature trim on the thermostat?
> I mean, how do you know where to set the temperature and how do you
> measure a silicon chip's temperature accurately anyway? Not having the
> temp too high or low was discussed, so this is important.
> 
> PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
> Circle you might not worry so much about temperature   ;-)
> 
> SV

Well, today i have -24 deg C and i heard on the national radio
broadcast that there have been cooldnes records set for scandinavia
with -51 deg C in Karesuando Sweden, and -52.2 deg C in Sodankyl??,
Finland!!!

So we might just start to heat up our LM3046 tripple expo ovens over
here at:
http://home8.swipnet.se/~w-88660/schpcb.htm


BJ (in "not go out side the house country" untill spring time!!) 

Hmm, perhaps one could test the oven now outside the house instead 
of using freese spray!! :)



From M.Rogers at cs.ucl.ac.uk  Thu Jan 28 15:41:14 1999
From: M.Rogers at cs.ucl.ac.uk (Michael ROGERS)
Date: Thu, 28 Jan 1999 15:41:14 +0100
Subject: vco7c thermal results
In-Reply-To: Your message of "Mon, 25 Jan 1999 16:25:44 EST." <199901252131.QAA18014@smtp3.mindspring.com>
Message-ID: <988.917538074@cs.ucl.ac.uk>


>I did a few experiments for the fun of it. I set the vco at 440hz then
>sprayed freeze on the 3046 for 1 sec. freq went up to 582hz . It took it
>about 60secs to recover to 440hz then after a little minor drifting
>stabilizing at 440hz in about 3mins. Then I took my 45w iron and placed it
>in the middle of the 3046 for 30secs. The freq went down to 382hz again it
>took it about 60secs to recover to 440hz stabilizing in about 3mins. So I
>got out the hair dryer full bore and max heat about 6" from the board for
>30secs freq went down to 332hz and took about 5mins to fully recover.

New LFO3 = VCO7 + army surplus flamethrower



From b.layer at vikingelectronics.com  Thu Jan 28 16:16:46 1999
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 28 Jan 1999 09:16:46 -0600
Subject: A few thoughts on heat tests and heaters
In-Reply-To: <9901272255551114@greymatter.com>
Message-ID: <3.0.6.32.19990128091646.007e33c0@192.168.210.18>

Hey David,

>With high-power radar, it is better to use physical waveguides than 
>coaxial cable.  Waveguides are sealed metal channels whose physical 
>dimentions are the same as one wavelength of the RF being carried - 
>makes for a very low loss situation.

Ok, I'm familiar with the waveguide principle.

>Only problem is that condensation kills the efficiency.  The 
>waveguides are filled with pressurised Nitrogen ( a PSI or two above 
>ambient ) and baked - silica gel removes the moisture and a pony 
>bottle of N2 gas keeps any pinhole leaks from causing problems - 
>positive pressure...

How interesting.

>Obligatory audio information:
>
>During WW2, the frequencies of RADAR were much lower and the
>wavelength for the waves were about the same as the wavelengths
>of sound waves in air.  There was a line of loudspeakers ( Karlsen? )
>developed after WW2 that essentially took broadband RF antenna
>designs and tweaked the impedences a bit to match a physical speaker
>instead of an RF waveguide.

Hmmm. Could this be the highly-touted 'Carlson' enclosure? The Carlson
features a strange front aperture, with a rougly logarithmic-curve shape.
It is driven by a 15" Jensen or Altec co-axial driver, the number I cannot
remember.

Pretty cool item, but honky as heck. Not nice listening, and I'm comparing
it to my JBL 4311 monitors (which have a serious 'reputation for
coloration' of their own).

>Very very high effeciency.  Frequency response was not linear but 
>nothing else was at that time either so it didn't matter.
 
Amen. Beat the band with 2 watts. So is anyone interested in building a
really simple, but nice sounding micropower OTL? 1 watt of screaming direct
coupled energy.


Bill Layer
Sales Technician
<b.layer at vikingelectronics.com>

+----------------------------------+
     Viking Electronics, Inc.
       1531 Industrial St.
    Hudson, WI. 54016 - U.S.A
      715.386.8861 ext. 210
 <http://www.vikingelectronics.com>
+----------------------------------+

"Telecom Solutions for the 21st Century"

 



From icumedia at flash.net  Thu Jan 28 17:18:45 1999
From: icumedia at flash.net (i.c. ultramedia)
Date: Thu, 28 Jan 1999 11:18:45 -0500
Subject: Opinions: On op amp replacement
Message-ID: <v02140b06b2d63bcfadb4@[209.30.26.84]>

I was recently given the advice to replace all the 741 and 748 op amps (on
a paia modular)
with LM301AN's, and LF351N's--------

2 questions.

1--Anyone have opinions on *how much* difference this might make? They're
relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
told, but I'll need about 20, so thought I'd ask.
2--Any good projects with which to use the 741/748s that will be left over,
or are they that useless...?


Thanks gurus, for the thoughts...

charles morpheus
icumedia

>I also found that if you change all the 748 op amps to LM301AN's, and 741
>op amps to LF351N's that the system becomes much quieter and more stable.
>Apparently the 741's and 748's, are the worst op amps you can get, and buy
>changing them to newer, higher quality op amps, improves performance
>dramatically (I got this info from a former ARP tech).





From mirwin1 at istar.ca  Thu Jan 28 19:35:21 1999
From: mirwin1 at istar.ca (Michael B. Irwin)
Date: Thu, 28 Jan 1999 13:35:21 -0500
Subject: Expo conv. heater (tomg et al.)
References: <199901281143.MAA17584@window.intermetall.de>
Message-ID: <36B0ADE8.B9F6984E@istar.ca>

The Moog Prodigy service manual shows how to set up the CA3046 heated
expo-converters used in the VCO's. Basically disconnect the heater power
and adjust a trimmer for the correct Vbe at the ambient temperature ( a
temperature vs. Vbe chart is given ). The manual can be found in the
Manuals section of the E-Music DIY Archive
(http://aupe.phys.andrews.edu/diy_archive). Hope this is some help with
your design.




From jhaible at primus-online.de  Thu Jan 28 21:39:48 1999
From: jhaible at primus-online.de (jhaible)
Date: Thu, 28 Jan 1999 21:39:48 +0100
Subject: Opinions: On op amp replacement
Message-ID: <19990129001222.4562.qmail@nuernberg2.pop.metronet.de>

> I was recently given the advice to replace all the 741 and 748 op amps
(on
> a paia modular)
> with LM301AN's, and LF351N's--------
> 
> 2 questions.
> 
> 1--Anyone have opinions on *how much* difference this might make? They're
> relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
> told, but I'll need about 20, so thought I'd ask.
> 2--Any good projects with which to use the 741/748s that will be left
over,
> or are they that useless...?
> 
> 
> Thanks gurus, for the thoughts...
> 
> charles morpheus
> icumedia
> 
> >I also found that if you change all the 748 op amps to LM301AN's, and
741
> >op amps to LF351N's that the system becomes much quieter and more
stable.
> >Apparently the 741's and 748's, are the worst op amps you can get, and
buy
> >changing them to newer, higher quality op amps, improves performance
> >dramatically (I got this info from a former ARP tech).

There is no general answer unless somebody is familiar with the whole
circuit in question.
As a matter of fact, you can replace these opamps in *many* cases, but
there are
exceptions. There are circuits that rely on the low slew rate of an opamp
to smooth
glitches, there might be stability problems with a faster opamp in general,
and
the input common mode range of a 741 goes down to lower voltages than a
JFET
input opamp would. I have even seen pin 3 of a 741 being tied to the
negative rail
(not gnd !), and the whole thing still working as linear inverting
amplifier with a
feedback loop comprising an external transistor. (That's the MK 2 VCS3,
btw.)

If you keep these exceptions in mind (are there more ?), you can probably
decide
which opamp can savely be replaced and where to be careful. I'd suggest
exchanging
them one by one, and not all at one time, if you are not sure. I'd leave
opamps
that are part of the power supply alone. (There are PSUs with a 723 for
positive, and
an opamp for negative rail.)

JH. 




From magnus at analogue.org  Thu Jan 28 22:59:24 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 28 Jan 1999 22:59:24 +0100
Subject: Expo conv. heater (tomg et al.)
In-Reply-To: Your message of "Wed, 27 Jan 1999 17:08:29 -0800"
References: <36AFB888.FE8F09A7@k-online.com>
Message-ID: <199901282159.WAA15927@mail2.it.kth.se>

>>>>> "SV" == Steve Varner <varner at k-online.com> writes:

 SV> I haven't built a discrete VCO yet (just CEM chips in a kit VCO). I want
 SV> to build a 3046/thermostat circuit, but I have a few questions.

 SV> 1. Do you really need a separate power source for the heater part?
 SV> That's a real pain in the rear. You mentioned regulators and I've seen
 SV> separate supplies mentioned on the web... so that's why I want to know.

 SV> 2. Barry Klein suggested putting the 3046 under a styrofoam cover to
 SV> isolate the chip from heat loss or gain - sort of a chip calorimeter.
 SV> Has anyone done this?

Well, I guess someone has, but it makes perfect sence. This is BTW how
you improve crystal oscillators stability. There are even those that
use double ovens, and oven within a oven. When you reduces the static
heat transfer from the chip (by increasing the surrounding temperature
to be near equal) the regulator have less of a figth to do.

Also, one has to put some care into the design, so that you don't get
a oscillating heating pattern, we are talking well-damped to
over-damped here. But then, you migth miss the fun of another source
of incertainty ;)

 SV> 3. How do you know where to set the temperature trim on the thermostat?
 SV> I mean, how do you know where to set the temperature and how do you
 SV> measure a silicon chip's temperature accurately anyway? Not having the
 SV> temp too high or low was discussed, so this is important.

Well, when you put styrofoam over it, the body will not chill of that
much, so you get about the same temperature at the capsule surface
that you have at the silicon once you have stabilized in temperature.
If you look at the datasheets you can find comments on the heat
conduction of the capsule, using this and some other knowledge you can
get pretty close to the heat of the actual chip. You can also use a
transistor as temperature sensor, since there is this nice little
relation between temperature, voltage and current. You could hook up a
diff pair to act as a temperature sensor with compensation for the Rbe
resistance if you want. This becomes pretty accurate actually.

 SV> PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
 SV> Circle you might not worry so much about temperature   ;-)

Well, the cross-country and downhill skiing isn't the same in San
Diego as we cool guys require. This morning we had a freshly warm
breeze of -17 C (that is 1 F) here in Stockholm, but up north they
have a bit chilly with -42 C (-43 F) and so...

Cheers,
Magnus




From magnus at analogue.org  Thu Jan 28 23:04:31 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 28 Jan 1999 23:04:31 +0100
Subject: Expo conv. heater (tomg et al.)
In-Reply-To: Your message of "Thu, 28 Jan 1999 04:33:58 -0800"
References: <36B05936.1CF1@swipnet.se>
Message-ID: <199901282204.XAA16019@mail2.it.kth.se>

>>>>> "B" == BJ  <zzynt at swipnet.se> writes:
 >> PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
 >> Circle you might not worry so much about temperature   ;-)
 >> 
 >> SV

 B> Well, today i have -24 deg C and i heard on the national radio
 B> broadcast that there have been cooldnes records set for scandinavia
 B> with -51 deg C in Karesuando Sweden, and -52.2 deg C in Sodankyl??,
 B> Finland!!!

As you see we are getting warm winds here...

 B> So we might just start to heat up our LM3046 tripple expo ovens over
 B> here at:
 B> http://home8.swipnet.se/~w-88660/schpcb.htm

 B> BJ (in "not go out side the house country" untill spring time!!) 

 B> Hmm, perhaps one could test the oven now outside the house instead 
 B> of using freese spray!! :)

The benefit of this method is that it is truely natural. Also, cooling
hot equipment hasn't been cheaper than it is today...

Freeze,
Magnus (still warm thought)



From uzs159 at uni-bonn.de  Fri Jan 29 01:24:00 1999
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Fri, 29 Jan 1999 01:24:00 +0100
Subject: Opinions: On op amp replacement
In-Reply-To: <v02140b06b2d63bcfadb4@[209.30.26.84]>
Message-ID: <3.0.5.32.19990129012400.0090a830@ibm.rhrz.uni-bonn.de>

At 11:18 28.01.99 -0500, you wrote:
>I was recently given the advice to replace all the 741 and 748 op amps (on
>a paia modular)
>with LM301AN's, and LF351N's--------
>
>2 questions.
>
>1--Anyone have opinions on *how much* difference this might make? They're
>relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
>told, but I'll need about 20, so thought I'd ask.
>2--Any good projects with which to use the 741/748s that will be left over,
>or are they that useless...?
>
>
>charles morpheus
>icumedia

Quoting from the datasheet: 8-pin mini DIP all purpose noise injector. ;)
One can put them perhaps in a "Grungelizer" or "LoFi-enizer" effect module.
They are OK, if you use them with reduced bandwidth, I once used 741 in a
poweramp and it was noisy as hell, until I reduced the bandwidth to some
7-8 kHz, (I used this amp to drive a 15" speaker)

bye 
 Rene

             ,   : (uzs159 at uni-bonn.de)
|") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
|"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
                       




From allan.houston at lineone.net  Fri Jan 29 01:34:25 1999
From: allan.houston at lineone.net (Allan)
Date: Fri, 29 Jan 1999 00:34:25 -0000
Subject: SSM2038 or equivelent
Message-ID: <000001be4b1f$1f76c7a0$f43c63c3@default>

Could Someone send me details of where to get hold of this chip or
equivelent in UK, preferablky with some idea of price,and if possible where
to find a data sheet.

Cheers
Allan




From corley.brigman at intel.com  Fri Jan 29 01:57:00 1999
From: corley.brigman at intel.com (Brigman, Corley)
Date: Thu, 28 Jan 1999 16:57:00 -0800
Subject: Opinions: On op amp replacement
Message-ID: <199901290059.AAA17029@calliope1.fm.intel.com>

>They are OK, if you use them with reduced bandwidth, I once used 741 in a
>poweramp and it was noisy as hell, until I reduced the bandwidth to some
>7-8 kHz, (I used this amp to drive a 15" speaker)

i don't know if this directly applies, but I was recently reading about op
amps,
and they talked about "large signal" vs. "small signal" operation, with some

definition about where the cutoff point is. basically, the summary was that
an 
op amp works best with either small signal/large bandwidth or large
signal/small
bandwidth, and you can trade one off towards the other. this seems to
follow. 
this is due to the slew rate (if the slew rate is 1V/100MS, for instance (a 
fictional and VERY SLOW slew rate, it takes only 50 ms (20HZ) to go
full-scale 
for a .5V square wave, but 1000ms (1 second = 1HZ) to go full-scale for a
10V 
square wave. so, at 10V, the 20Hz signal will look like a triangle wave. not

necessarily "noisy", but at least "distorted"....this seems to explain
somewhat 
what you are seeing..

corley brigman
intel corp.
corley.brigman at intel.com

speaking for me, not for intel.



From merlin at ion.com.au  Fri Jan 29 02:14:35 1999
From: merlin at ion.com.au (Merlin Zener)
Date: Fri, 29 Jan 1999 11:14:35 +1000
Subject: "three phase" sig gen?
Message-ID: <36B10B7B.558B77FC@ion.com.au>

G'day all,

I was wondering if any of you gurus could help me out with a
simple cct for a signal generator. The outputs I want to be
like this:

     __
1.__|  |______|
        __
2._____|  |____
           __
3.________|  |_

It has to run off a 9V battery, other than that there's no
particular requrements I can think of. It's for a new type of
universal cable tester I'm thinking of.

Once I get it up and running I'll post a link to the complete
cct back to the list.

TIA

-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"



From 104065.2340 at compuserve.com  Fri Jan 29 02:35:02 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Thu, 28 Jan 1999 20:35:02 -0500
Subject: Expo conv. heater (tomg et al.)
Message-ID: <199901282035_MC2-6865-E411@compuserve.com>

Hi All

The recent thread on heated expo converters correctly discussed some of the
drawback:  increased leakage current, permanent change in tranny
characteristics if heated too high, mechanical stress, possible decreased
reliability.  Ok, how about an alternative: cool it instead.  You can get
Peltier junction coolers from many sources of surplus components pretty
cheap, just monitor Vbe and drive the Peltier in a closed loop (don't
forget to invert the gain stage, so you still have negative feedback).  The
reduced temperature will greatly reduce transistor leakage current,
reliability shouldn't be affected, and who cares if it gets too cold
(unless ice forms).  One drawback, the Peltier sucks a lot of current.
 Terry Michaels



From JWBarlow at aol.com  Fri Jan 29 05:23:07 1999
From: JWBarlow at aol.com (JWBarlow at aol.com)
Date: Thu, 28 Jan 1999 23:23:07 EST
Subject: Opinions: On op amp replacement
Message-ID: <732ec0a6.36b137ab@aol.com>

Since the topic has been brought up, I've been thinking for a long time about
changing out all the LM301s in the audio path of my ARP 2600 because they have
always sounded very noisy to me. I had always thought of using a TL071 or
possibly some OPxx part, with Jurgen's points being well taken of course. I'm
hoping someone would have some insight into this (Good, Bad or Ugly), though I
have no plans of doing this in the immediate future.

Any thoughts are appreciated!
John B.



From pfperry at melbpc.org.au  Fri Jan 29 07:47:20 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 29 Jan 1999 17:47:20 +1100
Subject: Opinions: On op amp replacement
Message-ID: <1.5.4.32.19990129064720.00d22418@popa.melbpc.org.au>

At 11:23 PM 28/01/99 EST, JWBarlow wrote:

>changing out all the LM301s in the audio path of my ARP 2600 because they have
>always sounded very noisy to me. I had always thought of using a TL071 

The LM301s might have compensation caps (pin 2 to 8) which you might want to
remove,
I dont know, just something to worry about..

paul perry Frostwave P/l Melbourne Australia




From pfperry at melbpc.org.au  Fri Jan 29 07:56:16 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 29 Jan 1999 17:56:16 +1100
Subject: "three phase" sig gen?
Message-ID: <1.5.4.32.19990129065616.00d2d660@popa.melbpc.org.au>

At 11:14 AM 29/01/99 +1000, Merlin Zener  wrote:
 help me out with a
>simple cct for a signal generator. The outputs I want to be
>like this:
>
>     __
>1.__|  |______|
>        __
>2._____|  |____
>           __
>3.________|  |_
>
>It has to run off a 9V battery, other than that there's no
>particular requrements I can think of. It's for a new type of
>universal cable tester I'm thinking of.
>
Do you mean square or sine?

If you mean square, then use a ring counter.

If you mean sine with 120 deg between phases, use a 3 stage phase shift
oscillator.
OK, there is less distortion on some outputs than others, but it is ok really.

If you mean adjacent but non-overlapping pulses, perhaps a shift register.

All these are guesses, I havn't built them..

paul perry Frostwave P/l Melbourne Australia




From martin.czech at intermetall.de  Fri Jan 29 08:00:16 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 29 Jan 1999 08:00:16 +0100 (MET)
Subject: "three phase" sig gen?
Message-ID: <199901290700.IAA25108@window.intermetall.de>

> 
> I was wondering if any of you gurus could help me out with a
> simple cct for a signal generator. The outputs I want to be
> like this:
> 
>      __
> 1.__|  |______|
>         __
> 2._____|  |____
>            __
> 3.________|  |_
> 

There are CMOS decoder chips. I think 4,8, and 10 steps.  Combined with
a counter you can build a little sequenzer that produces any pattern you
want. For simplicity you can OR the outputs with diodes, before going
to the output stage (load requirements).  A unused step output can be
used as asynchronous reset, to shorten the thing to the wanted number
of steps.  If you want glitch free performance you'll have to sample
the ORed output with another FF.


BTW, this way you can replace a rotary switch with an up (or up/down)
button.  You can have as many positions as you want. Problem is: no
memory after power down. The ELV generator I build over christmas uses
something like this for all switches (of course only voltage can be
switched, i.e. very little currents).


m.c. (no guru, just a simple engineer)




From martin.czech at intermetall.de  Fri Jan 29 08:04:40 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 29 Jan 1999 08:04:40 +0100 (MET)
Subject: Expo conv. heater (tomg et al.)
Message-ID: <199901290704.IAA25121@window.intermetall.de>

> The recent thread on heated expo converters correctly discussed some of the
> drawback:  increased leakage current, permanent change in tranny
> characteristics if heated too high, mechanical stress, possible decreased
> reliability.  Ok, how about an alternative: cool it instead.  You can get
> Peltier junction coolers from many sources of surplus components pretty
> cheap, just monitor Vbe and drive the Peltier in a closed loop (don't
> forget to invert the gain stage, so you still have negative feedback).  The
> reduced temperature will greatly reduce transistor leakage current,
> reliability shouldn't be affected, and who cares if it gets too cold
> (unless ice forms).  One drawback, the Peltier sucks a lot of current.
>  Terry Michaels

	
If you provide a good regulator circuit and isolation, you won't destroy any
trannys. esp. important for start up. 
My motto: better know leakage at constant temperature, as unknow leakage
at varying temperature, the later can't be compensated.

The cooler approach has one big disadvantage: it's not on chip.
The you can take an MAT0x with external heater as well.


m.c.
(waiting for the Norwegian blizzards to come) 




From merlin at ion.com.au  Fri Jan 29 08:17:40 1999
From: merlin at ion.com.au (Merlin Zener)
Date: Fri, 29 Jan 1999 17:17:40 +1000
Subject: "three phase" sig gen?
References: <199901290700.IAA25108@window.intermetall.de>
Message-ID: <36B16094.42F5782F@ion.com.au>

Thanks to the people who've already offered helpful replies:)

I was kind of hoping for a transistor-only solution - a little
more robust, I think.
Kind of a three-way flipflop...

once again, TIA...


-- 
Merlin Zener                            mailto:merlin at ion.com.au
Piano and Synthesizer               voice: (+61) (0) 418 779 594
Gold Coast, Australia              http://www.ion.com.au/~merlin

"No-one ever went blind from looking on the bright side of life"



From ryckebu at subasehp.san.mrms.navy.mil  Fri Jan 29 08:43:31 1999
From: ryckebu at subasehp.san.mrms.navy.mil (Jules Ryckebusch)
Date: Fri, 29 Jan 1999 07:43:31 +0000
Subject: Audio Op-Amps
Message-ID: <199901291550.HAA18299@subasehp.san.mrms.navy.mil>

Here are the best ones that I know of and use:

They all feature very low THD and noise, good bandwidth, the ability 
to drive a 10VRMS signal into 600 ohms. (Which mean they can drive 8 
ohm headphones when used with a 49 ohm series resistor)
single/dual
NE5532/5534 the original "audio" op-amp
OP-175/275 Analog Devices 
OPA604/2604 Burr Brown FET input works with up to +/-24VDC supply 
rails LM833 dual from National Semiconductor (I have it from inside 
sources this is a 5532 clone)
OPA134/2134 Burr Brown, Rail to Rail Audio Op-Amp. These are new, I 
have used them in a phono-pre amp. They will run on +/-15VDC rails 
but I think Burr Brown is trying for the low voltage market of 
multimedia computer 5Volt arena (Can't Blame them, big market)
The Best Speced Audio Op-Amp is the AD797 from Analog Devices. It is 
a little tricky to use, must be well decoupled and can't use large 
feedback resistors (like above 33K) with out special attention to 
detail.

I like all of these and they work very well. The problem with 
wholesale replacing 741's and the like is that some circuits may be 
designed around the original opamps limited bandwidth

Jules



From jorgen.bergfors at idg.se  Fri Jan 29 09:09:45 1999
From: jorgen.bergfors at idg.se (jorgen.bergfors at idg.se)
Date: Fri, 29 Jan 1999 9:09:45 +0100
Subject: Opinions: On op amp replacement
Message-ID: <TFSCMECW@idg.se>

Since the topic has been brought up, I've been thinking for a long time about
changing out all the LM301s in the audio path of my ARP 2600 because they have
always sounded very noisy to me. I had always thought of using a TL071 or
possibly some OPxx part, with Jurgen's points being well taken of course. I'm
hoping someone would have some insight into this (Good, Bad or Ugly), though I
have no plans of doing this in the immediate future.

Any thoughts are appreciated!
John B.

Why not use the Philips NE 5534 instead? It has one third the noise of the TL071 (4 nV/Hz). The slew rate is the same (13 V/us). It also has a higher output drive capability. Can drive headphones directly!
The NE 5532 is a dual verision in a standard 8 pin package. Same spec except the slew rate for some reason is a little lower (9 V/us).

/Jorgen

P.S. More info at:

http://www-us.semiconductors.philips.com/cgi-bin/newsearch/pip?typenr=NE5533/5533A/NE/SA/SE5534/5534A&searchstring=NE5533/5533A/NE/SA/SE5534/5534A

http://www-us.semiconductors.philips.com/acrobat/applicationnotes/AN142.pdf





From rsowa at WizjaTV.pl  Fri Jan 29 09:35:03 1999
From: rsowa at WizjaTV.pl (Roman Sowa)
Date: Fri, 29 Jan 1999 09:35:03 +0100
Subject: ODP: "three phase" sig gen?
Message-ID: <2BF6F749A4A3D11185AD00A0C94CF67A4D68EE@demon>

Use 4017 Johnson counter.

output 0 will be your 1.
1 free
2 is your 2.
3 free
4 is your 3.
5 free
6 connect to 4017 reset input

clock it with any generator and that's it

hope that was clear

Roman

> -----Oryginalna wiadomo??-----
> Od:	Merlin Zener [SMTP:merlin at ion.com.au]
> Wys?ano:	29 stycznia 1999 02:15
> Do:	DIY list
> Temat:	"three phase" sig gen?
> 
> G'day all,
> 
> I was wondering if any of you gurus could help me out with a
> simple cct for a signal generator. The outputs I want to be
> like this:
> 
>      __
> 1.__|  |______|
>         __
> 2._____|  |____
>            __
> 3.________|  |_
> 
> It has to run off a 9V battery, other than that there's no
> particular requrements I can think of. It's for a new type of
> universal cable tester I'm thinking of.
> 
> Once I get it up and running I'll post a link to the complete
> cct back to the list.
> 
> TIA
> 
> -- 
> Merlin Zener                            mailto:merlin at ion.com.au
> Piano and Synthesizer               voice: (+61) (0) 418 779 594
> Gold Coast, Australia              http://www.ion.com.au/~merlin
> 
> "No-one ever went blind from looking on the bright side of life"



From Juergen.Haible at nbgm.siemens.de  Fri Jan 29 12:13:43 1999
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 29 Jan 1999 12:13:43 +0100
Subject: VC Envelope
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582012FFAFF@nbgm336a.nbgm.siemens.de>

The promised VC ADSR has become a VC HADSR, with a (also voltage controlled)
Hold
time like the MS20 envelopes. The circuit is slightly larger now, but I
think one chip (TL074)
plus 16 discrete transistors still isn't that bad (;->).
The ADSR part is gated by the prolonged Gate signal, but triggered from the
normal Gate signal,
so you can retrigger the ENV even when it is in "Hold" state.

http://www.it.kth.se/~e93_mda/synths/friends/haible/hj_vc_hadsr.html

Hope you enjoy it !

It's simulated, and tested on the bench, but with potentiometers connected
by alligator clips, so it might not be completely optimized yet. Any hints
and suggestions are welcome.



JH.



From steveg at bss10a.staffs.ac.uk  Fri Jan 29 11:36:20 1999
From: steveg at bss10a.staffs.ac.uk (Dr S Grainger)
Date: Fri, 29 Jan 1999 11:36:20
Subject: NPN/PNP Transistor Packages
Message-ID: <3.0.3.16.19990129113620.368f6f76@bss10a.staffs.ac.uk>

Dear All,

	Anyone out there had any experience using NPN/PNP
	transistor pair for temperature compensation as applied
	to VCF circuitry.

	Moog seemed to use this in a number of models (Mini,
	Taurus I, Prodigy) with 'discrete' devices and recommended
	their matching Vbe values.

	Rohm produce some SMT NPN/PNP packages (IMZ1A)
	which I would assume are matched thermally.

	Comments ?

	Steve Grainger



From martin.czech at intermetall.de  Fri Jan 29 12:56:51 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 29 Jan 1999 12:56:51 +0100 (MET)
Subject: Opinions: On op amp replacement
Message-ID: <199901291156.MAA25962@window.intermetall.de>

> 
> Why not use the Philips NE 5534 instead? It has one third the noise of the TL071 (4 nV/Hz). The slew rate is the same (13 V/us). It also has a higher output drive capability. Can drive headphones directly!
> The NE 5532 is a dual verision in a standard 8 pin package. Same spec except the slew rate for some reason is a little lower (9 V/us).
> 

Be carefull.  

The 5532 has quite high input leakage and bias currents, also offset
voltages. Replacing a TL071 with one 5534 won't work in applications with
high signal impedance, eg. filter cap buffer, integrator.  You introduce
a lot of offset (very temp dependend and source resistance dependend)
and leakage in your circuit. The 553x series is for standard audio signal
path, ie.  no leakage and no offset requierement. Then you can benefit
from it's high bandwidth and low nois like you pointed out.

m.c.




From pfperry at melbpc.org.au  Fri Jan 29 13:17:44 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 29 Jan 1999 23:17:44 +1100
Subject: "three phase" sig gen?
Message-ID: <1.5.4.32.19990129121744.00d26418@popa.melbpc.org.au>

At 05:17 PM 29/01/99 +1000, Merlin Zener  wrote:
>Thanks to the people who've already offered helpful replies:)
>
>I was kind of hoping for a transistor-only solution - a little
>more robust, I think.
>Kind of a three-way flipflop...

Welllll....just build a 3 stage flipflop!
It's just the same as a two, it's called a 'walking ring'.
With large walking rngs, there is the problem of more than
one section being 'on'..
But, how to be sure it has only one 'on' at a time?

Really, the more I think about it, I'd use 3 555 one shots 
in a circle, with a button to start them off (or some automatic
'power up' system). There isn't anything much more robust than these!

paul perry melbourne australia

Perhaps a byproduct of this will be a really interesting envelope generator?
Speaking of which, has anyone combined an envelope gen with a highly 
resonant LP filter around 0.1 Hz to give 'ripples' on the envelope?




From martin.czech at intermetall.de  Fri Jan 29 14:26:11 1999
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 29 Jan 1999 14:26:11 +0100 (MET)
Subject: Opinions: On op amp replacement
Message-ID: <199901291326.OAA26157@window.intermetall.de>

I'd say:

LF41x    etc. for low offset and offset drift, rel. low leak
NE553x   for high bandwitdh, low noise
TL07x    for rel. low noise, low leak
CA3140   low leakage
TL08x    else

I really would like to test "very low" leak types like CA3140
against TL07x or LF041x.

The 3140 has mosfet inputs, but ESD-Protection diode junctions as well,
if Ta max is set to 45C, how much more leakage would a 41x or a 07x 
take ? Is it really an order of magnitude ? I doubt. 
And the data sheet also. And the 3140 has certainly a lot of disadvantages.

Old schematics (and our concepts are all very old) suffer from the fact,
that at THAT time no other ICs existet. Today one should consider using
something better.

Of course, a clone is a clone, better stay to original hardware then.

But: semiconductor manufacuturers change masks without notice,
it is very doubtfull if a 1978 3140 is really the same as some 3140
from today, even worse with second source products.

Circuits that rely on parasitic effects may not even work
with todays hardware, even if the stamp code says "3140".

m.c.




From MHELIN at tne01.ntc.nokia.com  Fri Jan 29 15:48:37 1999
From: MHELIN at tne01.ntc.nokia.com (Mikko Helin)
Date: Fri, 29 Jan 1999 16:48:37 +0200
Subject: VST Synth
Message-ID: <990129164837.530261b6@tnclus.ntc.nokia.com>

Hi,

Check this out:

http://www.steinberg.net/namm99/images/vst_synth.jpg
http://www.steinberg.net/namm99/vst_synth.html

Nice Moogy synth.


Anyway, it seems that VST 2.0 SDK will support low-latency
synthesis with MIDI input.

-Mikko





From scopey at hooked.net  Fri Jan 29 16:07:26 1999
From: scopey at hooked.net (Jeff Baker)
Date: Fri, 29 Jan 1999 07:07:26 -0800
Subject: Opinions: On op amp replacement
References: <v02140b06b2d63bcfadb4@[209.30.26.84]>
Message-ID: <36B1CEAC.50B46D2A@hooked.com>

i haven't studied the data sheets, but what about replacing 741's with
OP271's?

i.c. ultramedia wrote:

> I was recently given the advice to replace all the 741 and 748 op amps (on
> a paia modular)
> with LM301AN's, and LF351N's--------
>
> 2 questions.
>
> 1--Anyone have opinions on *how much* difference this might make? They're
> relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
> told, but I'll need about 20, so thought I'd ask.
> 2--Any good projects with which to use the 741/748s that will be left over,
> or are they that useless...?
>
> Thanks gurus, for the thoughts...
>
> charles morpheus
> icumedia
>
> >I also found that if you change all the 748 op amps to LM301AN's, and 741
> >op amps to LF351N's that the system becomes much quieter and more stable.
> >Apparently the 741's and 748's, are the worst op amps you can get, and buy
> >changing them to newer, higher quality op amps, improves performance
> >dramatically (I got this info from a former ARP tech).




From synth1 at airmail.net  Fri Jan 29 17:44:13 1999
From: synth1 at airmail.net (Paul Schreiber)
Date: Fri, 29 Jan 1999 10:44:13 -0600
Subject: Audio Op-Amps
Message-ID: <005201be4ba6$9aadfa60$1db8fea9@p400>

>From extensive Audio Precision testing, the LM8xx series from National
suffers from
large THD at frequencies above 1.2Khz, which the 5532 does not. I would
never consider
them.

Also, you have to watch the Icc of the 553x parts. If you have 20
replacements, your
cheesy 3-terminal regulators will get toasty.

For price/performance ratio, still hard to beat TL07x parts. We use OP275s
in the MOTM
synthesizer with great results. Must bypass: alot (read....most) synths I've
worked on had
ZERO bypass caps on the op amps (includes the $$overpriced$$ Moog modular
with the
741 op amps in the 921 VCO summers!). TL07x may be the best overall
"generic" choice.

Lastly, there is another bipolar dual op amp called a RC4558 that JRC made.
Used EXTENSIVELY in early
Yamaha synths, mixers, cd players, and car stereos. Not a bad part, was
about 1/2 the price of the TL07x
in 1984. Makes a difference: JRC rep told me Yamaha used 125,000 a WEEK!

Paul Schreiber
Synthesis Technology
www.synthtech.com





From hbissell at ROBOTRON.com  Fri Jan 29 18:03:24 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:03:24 -0500
Subject: Expo conv. heater (tomg et al.)
Message-ID: <DA1512108AB7D2119DE200104BC67C5B0527@ROBOMAIL>

You don't need a separate heater power source, but it might put a strain on
the existing power supply, and the traces on the pcb might not like the
additional voltage drops. Decoupling might be a problem as the heater cycles
on and off. So, a separate power source might be a good thing. Keeping the
circiut under a styrofoam cup would isolate the chip from air movement,
which would be a very good thing because even a tiny breeze would change the
thermal environment drastically. The right temperature is above the highest
expected temperature, in use. About 120 degrees F. would be my best guess ?
Not letting the chip overshoot is more important than the actual temp.
Again, the styrofaom cup is a good idea. A not-obvious point is that for
stability and lack of overshoot you want to make the temp. loop faster in
response. (I tried slowing a similar circuit for along time before I
discovered what I was doing wrong.) Harry :-)

> -----Original Message-----
> From:	Steve Varner [SMTP:varner at k-online.com]
> Sent:	Wednesday, January 27, 1999 8:08 PM
> To:	synth-diy
> Subject:	Expo conv. heater (tomg et al.)
> 
> I haven't built a discrete VCO yet (just CEM chips in a kit VCO). I want
> to build a 3046/thermostat circuit, but I have a few questions.
> 
> 1. Do you really need a separate power source for the heater part?
> That's a real pain in the rear. You mentioned regulators and I've seen
> separate supplies mentioned on the web... so that's why I want to know.
> 
> 2. Barry Klein suggested putting the 3046 under a styrofoam cover to
> isolate the chip from heat loss or gain - sort of a chip calorimeter.
> Has anyone done this?
> 
> 3. How do you know where to set the temperature trim on the thermostat?
> I mean, how do you know where to set the temperature and how do you
> measure a silicon chip's temperature accurately anyway? Not having the
> temp too high or low was discussed, so this is important.
> 
> PS, if you folks lived in San Diego instead of 2 degrees from the Arctic
> Circle you might not worry so much about temperature   ;-)
> 
> SV



From hbissell at ROBOTRON.com  Fri Jan 29 18:08:37 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:08:37 -0500
Subject: A few thoughts on heat tests and heaters
Message-ID: <DA1512108AB7D2119DE200104BC67C5B0528@ROBOMAIL>

The "Carlson" (Karlsen?) enclosure actually works well over the frequency
range intended, but like the exponential horn, it has to be REALLY BIG.
Really big was required when a high power amp was 15 watts or so. (Really
big is still better... Size does matter :-) Harry

> -----Original Message-----
> From:	dave.halliday at greymatter.com [SMTP:dave.halliday at greymatter.com]
> Sent:	Thursday, January 28, 1999 1:02 AM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	Re: A few thoughts on heat tests and heaters
> 
> >>I saw a schematic on a radar transmitter for a air traffic control
> >>tower.. it had a seperate schematic for nitrogen lines.. nitrogen is the
> >>only way to cool without condensation supposedly..
> >      
> >     So was that an immersion system then? A pure liquid nitrogen bath
> would
> >     certainly be anhydrous... Or was the nitrogen used in another
> manner?
> 
> 
> 
> With high-power radar, it is better to use physical waveguides than 
> coaxial cable.  Waveguides are sealed metal channels whose physical 
> dimentions are the same as one wavelength of the RF being carried - 
> makes for a very low loss situation.
> 
> Only problem is that condensation kills the efficiency.  The 
> waveguides are filled with pressurised Nitrogen ( a PSI or two above 
> ambient ) and baked - silica gel removes the moisture and a pony 
> bottle of N2 gas keeps any pinhole leaks from causing problems - 
> positive pressure...
> 
> 
> 
> 
> Obligatory audio information:
> 
> During WW2, the frequencies of RADAR were much lower and the
> wavelength for the waves were about the same as the wavelengths
> of sound waves in air.  There was a line of loudspeakers ( Karlsen? )
> developed after WW2 that essentially took broadband RF antenna
> designs and tweaked the impedences a bit to match a physical speaker
> instead of an RF waveguide.
> 
> Very very high effeciency.  Frequency response was not linear but 
> nothing else was at that time either so it didn't matter.
> 
> 
> 
> 
> 
> --- Via Silver Xpress V4.4 [Reg]



From hbissell at ROBOTRON.com  Fri Jan 29 18:21:16 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:21:16 -0500
Subject: Opinions: On op amp replacement
Message-ID: <DA1512108AB7D2119DE200104BC67C5B052C@ROBOMAIL>

The 5533 and 5534 are compensated for minimum gain of Three (thats why the
slew is faster.) If the gain of the circuit is less than three (at any
frequency....) expect bad times (oscillation etc.) Harry.

> -----Original Message-----
> From:	jorgen.bergfors at idg.se [SMTP:jorgen.bergfors at idg.se]
> Sent:	Friday, January 29, 1999 3:10 AM
> To:	JWBarlow at aol.com; synth-diy at mailhost.bpa.nl
> Subject:	Re: Opinions: On op amp replacement
> 
> Since the topic has been brought up, I've been thinking for a long time
> about
> changing out all the LM301s in the audio path of my ARP 2600 because they
> have
> always sounded very noisy to me. I had always thought of using a TL071 or
> possibly some OPxx part, with Jurgen's points being well taken of course.
> I'm
> hoping someone would have some insight into this (Good, Bad or Ugly),
> though I
> have no plans of doing this in the immediate future.
> 
> Any thoughts are appreciated!
> John B.
> 
> Why not use the Philips NE 5534 instead? It has one third the noise of the
> TL071 (4 nV/Hz). The slew rate is the same (13 V/us). It also has a higher
> output drive capability. Can drive headphones directly!
> The NE 5532 is a dual verision in a standard 8 pin package. Same spec
> except the slew rate for some reason is a little lower (9 V/us).
> 
> /Jorgen
> 
> P.S. More info at:
> 
> http://www-us.semiconductors.philips.com/cgi-bin/newsearch/pip?typenr=NE55
> 33/5533A/NE/SA/SE5534/5534A&searchstring=NE5533/5533A/NE/SA/SE5534/5534A
> 
> http://www-us.semiconductors.philips.com/acrobat/applicationnotes/AN142.pd
> f
> 



From costello at seanet.com  Fri Jan 29 18:38:19 1999
From: costello at seanet.com (Sean Costello)
Date: Fri, 29 Jan 1999 09:38:19 -0800
Subject: "three phase" sig gen?
References: <1.5.4.32.19990129121744.00d26418@popa.melbpc.org.au>
Message-ID: <36B1F20B.7D236D1A@seanet.com>

Paul Perry wrote:

> Perhaps a byproduct of this will be a really interesting envelope generator?
> Speaking of which, has anyone combined an envelope gen with a highly
> resonant LP filter around 0.1 Hz to give 'ripples' on the envelope?

Or an envelope generator mixed with lowpass filtered white noise? The
result would probably sound similar to reverberation (i.e. somewhat
erratic fluctuations in volume as the sound decays).  I should give it a
try today in Csound, just to see how it works.

Sean Costello



From hbissell at ROBOTRON.com  Fri Jan 29 18:48:26 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:48:26 -0500
Subject: Opinions: On op amp replacement
Message-ID: <DA1512108AB7D2119DE200104BC67C5B052F@ROBOMAIL>

I find the greatest reductions in circuit (audio) noise often come from
replacing Carbon Comp. resistors with Metal Film. The metal films are
usually 1%, which makes summing and diff amps happier at the same time.
Also, faster op-amps somtimes do weird things. I built a phase shifter with
quad op amps (LM324) and replaced them with the TL084 (it oscillated at a
near ultrasonic frequency). It drove my mother's dog nuts (but she couldn't
hear it). Made me want to not fix it (I hated that Dog...... :-)

> -----Original Message-----
> From:	Rene Schmitz [SMTP:uzs159 at uni-bonn.de]
> Sent:	Thursday, January 28, 1999 7:24 PM
> To:	icumedia at flash.net
> Cc:	synth-diy at mailhost.bpa.nl
> Subject:	Re: Opinions: On op amp replacement
> 
> At 11:18 28.01.99 -0500, you wrote:
> >I was recently given the advice to replace all the 741 and 748 op amps
> (on
> >a paia modular)
> >with LM301AN's, and LF351N's--------
> >
> >2 questions.
> >
> >1--Anyone have opinions on *how much* difference this might make? They're
> >relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
> >told, but I'll need about 20, so thought I'd ask.
> >2--Any good projects with which to use the 741/748s that will be left
> over,
> >or are they that useless...?
> >
> >
> >charles morpheus
> >icumedia
> 
> Quoting from the datasheet: 8-pin mini DIP all purpose noise injector. ;)
> One can put them perhaps in a "Grungelizer" or "LoFi-enizer" effect
> module.
> They are OK, if you use them with reduced bandwidth, I once used 741 in a
> poweramp and it was noisy as hell, until I reduced the bandwidth to some
> 7-8 kHz, (I used this amp to drive a 15" speaker)
> 
> bye 
>  Rene
> 
>              ,   : (uzs159 at uni-bonn.de)
> |") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
> |"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
>                        



From hbissell at ROBOTRON.com  Fri Jan 29 18:51:09 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:51:09 -0500
Subject: Opinions: On op amp replacement
Message-ID: <DA1512108AB7D2119DE200104BC67C5B0530@ROBOMAIL>

Also, most op-amps have some current limiting for protection. Driving a
capacitive load with a constant (limited) current will definately make
triangle waves, regardless of slew-rate. Harry

> -----Original Message-----
> From:	Brigman, Corley [SMTP:corley.brigman at intel.com]
> Sent:	Thursday, January 28, 1999 7:57 PM
> To:	"icumedia at flash.net" ; "Rene Schmitz" 
> Cc:	"synth-diy at mailhost.bpa.nl" 
> Subject:	RE: Opinions: On op amp replacement
> 
> 
> >They are OK, if you use them with reduced bandwidth, I once used 741 in a
> >poweramp and it was noisy as hell, until I reduced the bandwidth to some
> >7-8 kHz, (I used this amp to drive a 15" speaker)
> 
> i don't know if this directly applies, but I was recently reading about op
> amps,
> and they talked about "large signal" vs. "small signal" operation, with
> some
> 
> definition about where the cutoff point is. basically, the summary was
> that
> an 
> op amp works best with either small signal/large bandwidth or large
> signal/small
> bandwidth, and you can trade one off towards the other. this seems to
> follow. 
> this is due to the slew rate (if the slew rate is 1V/100MS, for instance
> (a 
> fictional and VERY SLOW slew rate, it takes only 50 ms (20HZ) to go
> full-scale 
> for a .5V square wave, but 1000ms (1 second = 1HZ) to go full-scale for a
> 10V 
> square wave. so, at 10V, the 20Hz signal will look like a triangle wave.
> not
> 
> necessarily "noisy", but at least "distorted"....this seems to explain
> somewhat 
> what you are seeing..
> 
> corley brigman
> intel corp.
> corley.brigman at intel.com
> 
> speaking for me, not for intel.



From hbissell at ROBOTRON.com  Fri Jan 29 18:57:03 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 12:57:03 -0500
Subject: Opinions: On op amp replacement
Message-ID: <DA1512108AB7D2119DE200104BC67C5B0532@ROBOMAIL>

741 and 1458 op amps have a nice property... the will not latch up if
overdriven. Many very good op-amps have a problem where the output will go
the the negative supply when overdriven positive, and vice versa. They will
also STICK there for an extended period of time after the removal of the
overdrive.
	This is the absolute kiss of death if you are trying to make a
'temperature control loop' and must be guarded against. (see the Jim
Williams chip heater circuits, etc.) Now who would want to make a chip get
hot, anyway ?  ;-)   Harry.

> -----Original Message-----
> From:	jhaible [SMTP:jhaible at primus-online.de]
> Sent:	Thursday, January 28, 1999 3:40 PM
> To:	synth-diy at mailhost.bpa.nl; i.c. ultramedia
> Subject:	Re: Opinions: On op amp replacement
> 
> > I was recently given the advice to replace all the 741 and 748 op amps
> (on
> > a paia modular)
> > with LM301AN's, and LF351N's--------
> > 
> > 2 questions.
> > 
> > 1--Anyone have opinions on *how much* difference this might make?
> They're
> > relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
> > told, but I'll need about 20, so thought I'd ask.
> > 2--Any good projects with which to use the 741/748s that will be left
> over,
> > or are they that useless...?
> > 
> > 
> > Thanks gurus, for the thoughts...
> > 
> > charles morpheus
> > icumedia
> > 
> > >I also found that if you change all the 748 op amps to LM301AN's, and
> 741
> > >op amps to LF351N's that the system becomes much quieter and more
> stable.
> > >Apparently the 741's and 748's, are the worst op amps you can get, and
> buy
> > >changing them to newer, higher quality op amps, improves performance
> > >dramatically (I got this info from a former ARP tech).
> 
> There is no general answer unless somebody is familiar with the whole
> circuit in question.
> As a matter of fact, you can replace these opamps in *many* cases, but
> there are
> exceptions. There are circuits that rely on the low slew rate of an opamp
> to smooth
> glitches, there might be stability problems with a faster opamp in
> general,
> and
> the input common mode range of a 741 goes down to lower voltages than a
> JFET
> input opamp would. I have even seen pin 3 of a 741 being tied to the
> negative rail
> (not gnd !), and the whole thing still working as linear inverting
> amplifier with a
> feedback loop comprising an external transistor. (That's the MK 2 VCS3,
> btw.)
> 
> If you keep these exceptions in mind (are there more ?), you can probably
> decide
> which opamp can savely be replaced and where to be careful. I'd suggest
> exchanging
> them one by one, and not all at one time, if you are not sure. I'd leave
> opamps
> that are part of the power supply alone. (There are PSUs with a 723 for
> positive, and
> an opamp for negative rail.)
> 
> JH. 



From hbissell at ROBOTRON.com  Fri Jan 29 19:10:22 1999
From: hbissell at ROBOTRON.com (Bissell, Harry)
Date: Fri, 29 Jan 1999 13:10:22 -0500
Subject: Opinions: On op amp replacement
Message-ID: <DA1512108AB7D2119DE200104BC67C5B0536@ROBOMAIL>

The 3140 could have the diode leakage problem solved with external diodes in
series with the supplies, (but why bother). For Audio, the 3140 (correct me
if i'm wrong) Sucks (poor noise performance) ! For a sample and hold though,
it is an excellent choice. BUT watch out for the non-symetrical sourece and
sink current. It can source 10mA, but sink 1mA. Put that into your
capacitive load and smoke it...  ;-) harry

> -----Original Message-----
> From:	Martin Czech [SMTP:martin.czech at intermetall.de]
> Sent:	Friday, January 29, 1999 8:26 AM
> To:	jorgen.bergfors at idg.se
> Cc:	synth-diy at mailhost.bpa.nl
> Subject:	Re: Opinions: On op amp replacement
> 
> I'd say:
> 
> LF41x    etc. for low offset and offset drift, rel. low leak
> NE553x   for high bandwitdh, low noise
> TL07x    for rel. low noise, low leak
> CA3140   low leakage
> TL08x    else
> 
> I really would like to test "very low" leak types like CA3140
> against TL07x or LF041x.
> 
> The 3140 has mosfet inputs, but ESD-Protection diode junctions as well,
> if Ta max is set to 45C, how much more leakage would a 41x or a 07x 
> take ? Is it really an order of magnitude ? I doubt. 
> And the data sheet also. And the 3140 has certainly a lot of
> disadvantages.
> 
> Old schematics (and our concepts are all very old) suffer from the fact,
> that at THAT time no other ICs existet. Today one should consider using
> something better.
> 
> Of course, a clone is a clone, better stay to original hardware then.
> 
> But: semiconductor manufacuturers change masks without notice,
> it is very doubtfull if a 1978 3140 is really the same as some 3140
> from today, even worse with second source products.
> 
> Circuits that rely on parasitic effects may not even work
> with todays hardware, even if the stamp code says "3140".
> 
> m.c.



From buchanan at qualcomm.com  Fri Jan 29 19:29:28 1999
From: buchanan at qualcomm.com (Buck Buchanan)
Date: Fri, 29 Jan 1999 10:29:28 -0800
Subject: Opinions: On op amp replacement
In-Reply-To: <199901291156.MAA25962@window.intermetall.de>
Message-ID: <3.0.3.32.19990129102928.01793e00@mage.qualcomm.com>

At 12:56 PM 1/29/99 +0100, Martin Czech wrote:
>The 5532 has quite high input leakage and bias currents, also offset
>voltages. Replacing a TL071 with one 5534 won't work in applications with
>high signal impedance, eg. filter cap buffer, integrator.  You introduce
>a lot of offset (very temp dependend and source resistance dependend)
>and leakage in your circuit. The 553x series is for standard audio signal
>path, ie.  no leakage and no offset requierement. Then you can benefit
>from it's high bandwidth and low nois like you pointed out.


I'll have to second that.  I love the 5532 for audio paths where you don't
mind a lot of offset.  Not a terribly good choice for CV paths.  I seem to
remember these guys sucking down approx 4 mA so watch your current (I've
had to reluctantly leave them out of batter powered devices for this
reason).  The LF412 is an excellent dual with very low drift and offset -
good for CV paths however the OP07 is still much better (though only a
single w/same pinout as 741).

Original poster said:
>1--Anyone have opinions on *how much* difference this might make? They're
>relatively cheap (1.10 usd or so) and direct pin-compatible, I've been
>told, but I'll need about 20, so thought I'd ask.
>2--Any good projects with which to use the 741/748s that will be left over,
>or are they that useless...?

Low drift guys will improve stability in CV paths.  Low noise guys will
improve noise in audio paths.  *How much* difference is hard to define but
on a good instrument, I'd say it's worth doing *IF* there's a performance
parameter you really want to improve.  For example:  It might not be worth
messing with the LFOs or EVs at all while the VCOs could benefit from low
drift parts and the filters from low noise parts.  The 741s are great to
use when you specifically want a "slow" op-amp (people use 'em in triangle
shapers to help remove glitches).

Have fun!!!!

Buck




From oakley at techrepairs.freeserve.co.uk  Fri Jan 29 19:51:11 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Fri, 29 Jan 1999 18:51:11 -0000
Subject: Expo conv. heater (tomg et al.)
Message-ID: <008b01be4bbb$3139ed40$3c21883e@default>

Hi,

All this talk about ovens for keeping drifting under control. I worked
on Peltier temp controls in microwave detectors. Now these peltier heat
pumps are really good. They can be glued into place, ie. on top of your
3046, and you can make them hot or cold depending which way current goes
through them. Mind you they are expensive, 20UKP for a small pump, but
that could keep a few VCOs happy with some careful metal work. Oh and
the current draw can be quite large, we used +/- 1A, but that was to
keep it to with 0.1K. Op-amp servo loop with a small class B power amp
controlled the temp. PWM could be used, but these are noisy. You could
fix the temp at 290K, wrap in polystyrene, except for the heat sink, and
say goodbye to drifting expos. It wouldn't help other drifts like the
timing cap, CV resistors etc. but would really be rather cool.
Literally.

I had five small pumps on a heatsink to keep my drinks cool in the
summer. Now what would be rather good is to build one onto the substrate
in an integrated VCO. Tony Clark was going to do some small VCO
hybrids... perhaps this is the answer to drifting:-)

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From oakley at techrepairs.freeserve.co.uk  Fri Jan 29 19:55:15 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Fri, 29 Jan 1999 18:55:15 -0000
Subject: Opinions: On op amp replacement
Message-ID: <008c01be4bbb$32f5f520$3c21883e@default>

As Juergen says, don't do it unless you know the circuit. I had a power
amp with 748 and 741s in, swapped them for 5534 and OP27s, and the damn
thing blew up. Bang. High frequency oscillations killed the power trans
and shorted the two rails together. Nice.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at techrepairs.freeserve.co.uk

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From oakley at techrepairs.freeserve.co.uk  Fri Jan 29 20:10:44 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Fri, 29 Jan 1999 19:10:44 -0000
Subject: Opinions: On op amp replacement
Message-ID: <008e01be4bbb$3505e960$3c21883e@default>

>Why not use the Philips NE 5534 instead? It has one third the noise of
the TL071 (4 nV/Hz). The slew rate is the same (13 V/us). It also has a
higher output drive capability. Can drive headphones directly!
The NE 5532 is a dual verision in a standard 8 pin package. Same spec
except the slew rate for some reason is a little lower (9 V/us).

Take note the 5534 is not unity gain stable. It will need compensation.
Read the data sheet for further details. I use a 33p, it works quite
well, but if I was building a RIAA amp, I would look to using better
compensation methods.

The 5532 is unity gain stable. Lovely op-amp, but draws current, and
like the 5534 you must keep the inv and non-inv within 0V6 of each
other.

OP27 and OP275 are better but dearer. But the TL07x is a good part for
audio.

Regards,

Tony Allgood, Cumbria, UK

TB3030 circuit coming soon. Watch the archive.

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html






From clark at andrews.edu  Fri Jan 29 20:57:59 1999
From: clark at andrews.edu (Tony Clark)
Date: Fri, 29 Jan 1999 14:57:59 -0500 (EST)
Subject: Expo conv. heater (tomg et al.)
In-Reply-To: <008b01be4bbb$3139ed40$3c21883e@default>
Message-ID: <Pine.SOL.3.91.990129144334.691A-100000@edmund.cs.andrews.edu>

> I had five small pumps on a heatsink to keep my drinks cool in the
> summer. Now what would be rather good is to build one onto the substrate
> in an integrated VCO. Tony Clark was going to do some small VCO
> hybrids... perhaps this is the answer to drifting:-)

   Well I wasn't working with heaters though!  I wasn't happy with the 
current consumption (which everyone knows about) nor the stability of the 
whole temperature circuit in general.  So instead I tried different 
current mirror schemes to see if any of them were more temperature 
resistant.
   The idea was when I "discovered" that heating one side or the other of 
the mirror caused either an up or a down shift in frequency.  So in my 
limited knowledge, it seemd that if you added more transistors to the 
side that made the frequency go opposite of its normal drift (normally 
the frequency rises, I believe, so you'd add (in parallel) a few more 
transistors to the side that would decrease it) it'd balance out.  But it 
doesn't.  It seems to just shift the frequency point where the drift goes 
from positive to negative.
   BTW, when I did my temperature tests, I used a small toaster oven and 
put the whole circuit board inside.  The oven had holes drilled in it to 
place thermometers inside so that the temperature could be measured 
accurately (those ovens are hard to heat up slow!).
   Anyway, I won't even begin to try correlating anything with math.  
Someone else can do it.  :)
   I will most likely try Rene's method again and see if I have better 
luck.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From costello at seanet.com  Sat Jan 30 00:12:23 1999
From: costello at seanet.com (Sean Costello)
Date: Fri, 29 Jan 1999 15:12:23 -0800
Subject: Audio Op-Amps
References: <005201be4ba6$9aadfa60$1db8fea9@p400> <36B2B077.4ADF@swipnet.se>
Message-ID: <36B24057.8E3BC9AB@seanet.com>

BJ wrote:
> 
> Paul Schreiber wrote:
> 
> > Lastly, there is another bipolar dual op amp called a RC4558 that JRC made.
> > Used EXTENSIVELY in early
> > Yamaha synths, mixers, cd players, and car stereos. Not a bad part, was
> > about 1/2 the price of the TL07x
> > in 1984. Makes a difference: JRC rep told me Yamaha used 125,000 a WEEK!
> 
> Yes thats interesting, the japanese manufacturers seems to be wery found
> of the
> 4558, its used in a lot of old Korgs and some Roland synths too!

The JRC 4558 is supposedly the "secret ingredient" of the Ibanez TS-808
and TS-9 Tube Screamers.  Other 4558 chips apparently don't sound nearly
as good in those circuits.  

Sean Costello (who prefers the subtly world-rending sound of the Super
Fuzz to the wimply buzz of a Tube Screamer, although the TS-9 can sound
nice in front of an old Fender amp)



From pfperry at melbpc.org.au  Sat Jan 30 00:38:52 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 30 Jan 1999 10:38:52 +1100
Subject: Audio Op-Amps
Message-ID: <1.5.4.32.19990129233852.0068e28c@popa.melbpc.org.au>

Analog Devices SSM2135 worth considering
for low noise 5v rail-rail

paul perry Frostwave P/L Melbourne Australia




From cyborg0 at GlobalEyes.net  Sat Jan 30 00:48:50 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Fri, 29 Jan 1999 17:48:50 -0600
Subject: a diode behaving like a cap
Message-ID: <36B248E2.68A034C0@globaleyes.net>

Just wondering if its possible to use the depletion layer of a standard
reverse biased switching diode to act as a cap...
in other words, you have a diode put in the wrong way.. So, does the
depletion layer increase as the reverse voltage increases?

Another thing: is there any special reactions germanium diodes have
besides having a .3v bias?

Rob



From djblue at asu.edu  Sat Jan 30 01:51:22 1999
From: djblue at asu.edu (Reverend bluE)
Date: Fri, 29 Jan 1999 17:51:22 -0700 (MST)
Subject: Keyboard controller question
Message-ID: <Pine.GSO.3.96.990129174931.19334E-100000@general1.asu.edu>


I asked earlier and someone told me to go to www.tomg.net (or maybe it was
.org) but it doesn't work.  Other people have told this to me in the past for
other problems as well...  

anyway, I'm trying to find the directions for a 1 switch per key analog
controller... (I remember something about cutting the diodes and replacing
with resistors, but that's all..)

thanks again...
-b




From clark at andrews.edu  Sat Jan 30 02:00:19 1999
From: clark at andrews.edu (Tony Clark)
Date: Fri, 29 Jan 1999 20:00:19 -0500 (EST)
Subject: Audio Op-Amps
In-Reply-To: <1.5.4.32.19990129233852.0068e28c@popa.melbpc.org.au>
Message-ID: <Pine.SOL.3.91.990129195648.3028A-100000@edmund.cs.andrews.edu>

> Analog Devices SSM2135 worth considering
> for low noise 5v rail-rail

   I like the AD496 as a nice quad rail-to-rail.  In general, RTR's 
require careful circuit design.

   Tony

------------------------------------,----------------------------------
I can't drive (my Moog) 55!         |     The E-Music DIY Archive
------------------------------------|  
Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
------------------------------------'----------------------------------




From 104065.2340 at compuserve.com  Sat Jan 30 02:14:15 1999
From: 104065.2340 at compuserve.com (terry michaels)
Date: Fri, 29 Jan 1999 20:14:15 -0500
Subject: a diode behaving like a cap
Message-ID: <199901292015_MC2-6886-6C08@compuserve.com>

Message text written by Rob
>Just wondering if its possible to use the depletion layer of a standard
reverse biased switching diode to act as a cap...
in other words, you have a diode put in the wrong way.. So, does the
depletion layer increase as the reverse voltage increases?

Another thing: is there any special reactions germanium diodes have
besides having a .3v bias?
<

Rob:

The Varactor or varicap diode is designed to be used as you described. 
Increasing the reverse voltage increases the width of the depletion layer,
and reduces the capacitance.

The other thing about germanium diodes is much greater reverse leakage
current.

Terry Michaels



From jhaible at primus-online.de  Sat Jan 30 03:24:15 1999
From: jhaible at primus-online.de (jhaible)
Date: Sat, 30 Jan 1999 03:24:15 +0100
Subject: Opinions: On op amp replacement
Message-ID: <19990130120809.5115.qmail@nuernberg2.pop.metronet.de>

> I find the greatest reductions in circuit (audio) noise often come from
> replacing Carbon Comp. resistors with Metal Film. The metal films are
> usually 1%, which makes summing and diff amps happier at the same time.
> Also, faster op-amps somtimes do weird things. I built a phase shifter
with
> quad op amps (LM324) and replaced them with the TL084 (it oscillated at a
> near ultrasonic frequency). It drove my mother's dog nuts (but she
couldn't
> hear it). Made me want to not fix it (I hated that Dog...... :-)

I can confirm that. Phasers are aparently quite sensitive. No HF
attenuation
in a chain of all pass filters, opamps driving capacitive loads with
variable
resistors in series ...

Built a VACTROL-based 12-stage with TL072 and ran into problems. Works
fine with TL062's and 6 stages, though.

Replaced the dual opamps in my HiFli Clone with NE5532's and ran into
stability problems at extreme modulation settings.

Sometimes 741's and 1458's are not *that* bad !

BTW, I think one can avoid slew rate distortion on slow opamps by using
very small feedback (or load) resistors. They would clip the signal with
the
output current limit feature of the opamp, which should sound much more
pleasant than intermodulation, or than getting stuck at the supply rails.
Note the words "think" and "should" - I have not really made tests so far.
It's
just some speculation about existing designs.

JH.



From varner at k-online.com  Sat Jan 30 04:10:02 1999
From: varner at k-online.com (Steve Varner)
Date: Fri, 29 Jan 1999 19:10:02 -0800
Subject: Expo conv. heater (tomg et al.)
References: <Pine.SOL.3.91.990129144334.691A-100000@edmund.cs.andrews.edu>
Message-ID: <36B27805.EE359D01@k-online.com>

Hmmm.... maybe I should build a 19" rack-mount toaster and put the VCO
inside  ;-)
Seriously, I think I'll build a simple thermostat circuit, keep the
temperature at a sort of Death Valley level (120F), and put a slab of
styrofoam around the 3046. Would adding a separate power line from the power
bus, with separate traces on the PCB, help in solving fluctuation problems on
the VCO circuit? I don't think I want to use the pumps or Peltier things. I'm
not so sure I'm clear on the glass of distilled water test either  :-)

I'm a physics / chemistry person and so I'm not sure on the definitions of
some of the electronic terms you guys used. I don't want an entire
electronics coarse...just some clarification. I'm sure some of the other
folks out there are as lost as I am.
What do you mean by:
regulation loop
temperature loop and overshoot
SOA
migration and junction degradation
second breakdown

SV

----------------------------------------------------
Tony Clark wrote:

> > I had five small pumps on a heatsink to keep my drinks cool in the
> > summer. Now what would be rather good is to build one onto the substrate
> > in an integrated VCO. Tony Clark was going to do some small VCO
> > hybrids... perhaps this is the answer to drifting:-)
>
>    Well I wasn't working with heaters though!  I wasn't happy with the
> current consumption (which everyone knows about) nor the stability of the
> whole temperature circuit in general.  So instead I tried different
> current mirror schemes to see if any of them were more temperature
> resistant.
>    The idea was when I "discovered" that heating one side or the other of
> the mirror caused either an up or a down shift in frequency.  So in my
> limited knowledge, it seemd that if you added more transistors to the
> side that made the frequency go opposite of its normal drift (normally
> the frequency rises, I believe, so you'd add (in parallel) a few more
> transistors to the side that would decrease it) it'd balance out.  But it
> doesn't.  It seems to just shift the frequency point where the drift goes
> from positive to negative.
>    BTW, when I did my temperature tests, I used a small toaster oven and
> put the whole circuit board inside.  The oven had holes drilled in it to
> place thermometers inside so that the temperature could be measured
> accurately (those ovens are hard to heat up slow!).
>    Anyway, I won't even begin to try correlating anything with math.
> Someone else can do it.  :)
>    I will most likely try Rene's method again and see if I have better
> luck.
>
>    Tony
>
> ------------------------------------,----------------------------------
> I can't drive (my Moog) 55!         |     The E-Music DIY Archive
> ------------------------------------|
> Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
> http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
> ------------------------------------'----------------------------------






From varner at k-online.com  Sat Jan 30 04:53:43 1999
From: varner at k-online.com (Steve Varner)
Date: Fri, 29 Jan 1999 19:53:43 -0800
Subject: Integrating Capacitor
Message-ID: <36B28240.E62D3C70@k-online.com>

This question may have been asked recently, so if you want to email me
directly it's OK...

The current produced from the exponential converter in VCOs charges an
integrating capacitor. This cap is usually labelled "poly" (for
polystyrene capacitor). Now, these circuits were often layed out in the
late 70s and early 80s (such as the Electronotes VCOs). Some designs
were based on even older schematics from commercial synths. Back then I
don't think there were so many alternatives to polystyrene. Ceramic and
the older "mylar" caps would not be acceptable because of their specs I
think. Modern caps (20 years later) have much better specs than those
available in 1980 (temperature, tolerance, etc.). Some of the newer
ceramic caps and the polyester film caps have great specs. Is there some
other reason that polystyrene is important? They are listed as having
"excellent electrical characteristics, high reliability and stability,
low temperature coefficients, and small dissipation factor." I have a
feeling it is the low dissipation at high frequency (<0.1% at 100kHz)
that makes them good. Right? I bought some anyway, so I'll probably use
them in my VCO design. I just want to know why, and why I can't use some
other cap.

SV




From zzynt at swipnet.se  Sat Jan 30 08:10:47 1999
From: zzynt at swipnet.se (BJ)
Date: Fri, 29 Jan 1999 23:10:47 -0800
Subject: Audio Op-Amps
References: <005201be4ba6$9aadfa60$1db8fea9@p400>
Message-ID: <36B2B077.4ADF@swipnet.se>

Paul Schreiber wrote:

> Lastly, there is another bipolar dual op amp called a RC4558 that JRC made.
> Used EXTENSIVELY in early
> Yamaha synths, mixers, cd players, and car stereos. Not a bad part, was
> about 1/2 the price of the TL07x
> in 1984. Makes a difference: JRC rep told me Yamaha used 125,000 a WEEK!

Yes thats interesting, the japanese manufacturers seems to be wery found
of the
4558, its used in a lot of old Korgs and some Roland synths too!

And yesterday i had a fast look under the hod of my ZOOM 1201 reverb
unit
and what do we found as I/O signal amp, well a 4558 to the BB PCM3001
codec!!

BJ



From chordman at flash.net  Sat Jan 30 07:55:00 1999
From: chordman at flash.net (Scott Gravenhorst)
Date: Sat, 30 Jan 99 07:55:00
Subject: a diode behaving like a cap
Message-ID: <199901301552.JAA26367@echo.flash.net>

Paul Perry <pfperry at melbpc.org.au> wrote:
>At 08:14 PM 29/01/99 -0500, Terry Michaels wrote:
>
>>The other thing about germanium diodes is much greater reverse leakage
>>current.
>>
>and the other other thing is the 'rounder' shape of the knee in the v/i 
>curve, which is why they are sometimes preferred in distortion units

I think I know the answer to this, but are there any G-diodes still being
manufactured?

-- Scott Gravenhorst
-- RedWebMail by RedStarWare (srg)
-- FatMan Site: www.teklab.com/~chordman
-- Linux Rex, Linux Vobiscum





From LesPaul52 at aol.com  Sat Jan 30 09:19:25 1999
From: LesPaul52 at aol.com (LesPaul52 at aol.com)
Date: Sat, 30 Jan 1999 03:19:25 EST
Subject: CA3040?
Message-ID: <e70d0689.36b2c08d@aol.com>

dear list members

I stumbled upon a sample and hold circuit and see a CA3040 in the circuit, I
am looking around for this semiconductor and can't find it,

Does anybody know where to find them ? if they are obsolete, can you tell me
what it does and tell me if theres a substitute, thanks for your help

thanks,
TomHowell
LesPaul52 at aol.com
ICQ#13710243



From pfperry at melbpc.org.au  Sat Jan 30 09:24:08 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 30 Jan 1999 19:24:08 +1100
Subject: a diode behaving like a cap
Message-ID: <1.5.4.32.19990130082408.00660528@popa.melbpc.org.au>

At 08:14 PM 29/01/99 -0500, Terry Michaels wrote:

>The other thing about germanium diodes is much greater reverse leakage
>current.
>
and the other other thing is the 'rounder' shape of the knee in the v/i 
curve, which is why they are sometimes preferred in distortion units

paul perry melbourne australia




From pfperry at melbpc.org.au  Sat Jan 30 09:36:25 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 30 Jan 1999 19:36:25 +1100
Subject: Expo conv. heater (tomg et al.)
Message-ID: <1.5.4.32.19990130083625.00d390b8@popa.melbpc.org.au>

At 02:57 PM 29/01/99 -0500, Tony Clark  wrote:

>   The idea was when I "discovered" that heating one side or the other of 
>the mirror caused either an up or a down shift in frequency.  

These array heater things are, in the original 25 or so year old ckts, only
guaranteed if you use the actual numbered transistors in the array as given.

I personally think that a toaster oven would give such temperature differentials
across the chip (and everything else) as to make experimental observations
pointless.

paul perry melbourne australia

BTW, why not use a multiplexed PIC micro to perform exponential conversion?
Any programmers care to estimate how fast we could update say 8 convertors?

paul perry melbourne australia




From vco at mindspring.com  Sat Jan 30 11:01:56 1999
From: vco at mindspring.com (tomg)
Date: Sat, 30 Jan 1999 05:01:56 -0500
Subject: Keyboard controller question
Message-ID: <199901301007.FAA11555@smtp3.mindspring.com>



----------
> From: Reverend bluE <djblue at asu.edu>
> To: DIY <synth-diy at mailhost.bpa.nl>
> Subject: Keyboard controller question
> Date: Friday, January 29, 1999 7:51 PM
> 
> 
> I asked earlier and someone told me to go to www.tomg.net (or maybe it
was
> .org) but it doesn't work.  Other people have told this to me in the past
for
> other problems as well...  
> 
> anyway, I'm trying to find the directions for a 1 switch per key analog
> controller... (I remember something about cutting the diodes and
replacing
> with resistors, but that's all..)
> 
> thanks again...

It's http://www.tomg.vivid.net or http://www.synthesist.xsystem.net/efm/
look at http://www.mindspring.com/~vco/misc/kbd_2d.html
for a newer version.

-tg





From pfperry at melbpc.org.au  Sat Jan 30 13:11:35 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 30 Jan 1999 23:11:35 +1100
Subject: CA3040?
Message-ID: <1.5.4.32.19990130121135.00d37010@popa.melbpc.org.au>

At 03:19 AM 30/01/99 EST, TomHowell LesPaul52 wrote:

>I stumbled upon a sample and hold circuit and see a CA3040 in the circuit, I
>am looking around for this semiconductor and can't find it,
>
If this ckt really uses a CA3040 & not a misprint for a CA3140, you have
problems..
it was a wide band video amplifier with balanced differential input 
AND output!
what is worse, two different biasing systems can be used with it.
It was specially designed as a video amp with constant gain over temperature.
No modern equivalent exists, AFAIK.

paul perry Frostwave P/l Melbourne Australia




From jhaible at primus-online.de  Sat Jan 30 13:13:00 1999
From: jhaible at primus-online.de (jhaible)
Date: Sat, 30 Jan 1999 13:13:00 +0100
Subject: Expo conv. heater (tomg et al.)
Message-ID: <19990131015652.17393.qmail@nuernberg2.pop.metronet.de>

>    I will most likely try Rene's method again and see if I have better 
> luck.

Yes. And in case it should be too nonlinear or too noisy (which I don't
thik it
is for general audio range VCOs), one could still use a transistor of the
unheated
chip to measure the momentary temperature, and then scale the CV with a
linearized VCA.

JH.



From magnus at analogue.org  Sat Jan 30 14:02:06 1999
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 30 Jan 1999 14:02:06 +0100
Subject: "three phase" sig gen?
In-Reply-To: Your message of "Fri, 29 Jan 1999 17:17:40 +1000"
References: <36B16094.42F5782F@ion.com.au>
Message-ID: <199901301302.OAA15271@mail2.it.kth.se>

>>>>> "MZ" == Merlin Zener <merlin at ion.com.au> writes:

 MZ> Thanks to the people who've already offered helpful replies:)
 MZ> I was kind of hoping for a transistor-only solution - a little
 MZ> more robust, I think.
 MZ> Kind of a three-way flipflop...

Well, if you set up three single-pulse generators with the same time
and let them trigg each other I think you can get away with quite few
transistors. Ensure that you bootstrap one as "high" and two as "low".
The time-constant for each of them will set their time of the period
so that when you sum their time-constants up you get the total period
time.

This form of triggered single pulse generator should not be that
difficult to find, basically quite similar to the 2-transistor
astabile multivibrator.

Cheers,
Magnus



From THEKn0TiS at aol.com  Sat Jan 30 17:03:44 1999
From: THEKn0TiS at aol.com (THEKn0TiS at aol.com)
Date: Sat, 30 Jan 1999 11:03:44 EST
Subject: need 2  80017a roland vcf/vca
Message-ID: <f2a5835a.36b32d60@aol.com>

voice 2 and 6 vcf is out so im in need of 2 80017a vcf/vco chips

thanx 
shawn



From DCMagnuson at aol.com  Sat Jan 30 21:03:53 1999
From: DCMagnuson at aol.com (DCMagnuson at aol.com)
Date: Sat, 30 Jan 1999 15:03:53 EST
Subject: a diode behaving like a cap
Message-ID: <ce0b4860.36b365a9@aol.com>

In a message dated 1/30/99 11:50:23 AM Eastern Standard Time,
chordman at flash.net writes:

> 
>  I think I know the answer to this, but are there any G-diodes still being
>  manufactured?
>  

I just bought a package from Radio Shack on a whim....  so someone's still
making them.  I don't have any specific use in mind yet, but just grabbed them
for playing around with.

Dave Magnuson
Independent Music Site
http://members.aol.com/dcmagnuson



From thudson at cygnus.com  Sat Jan 30 21:11:24 1999
From: thudson at cygnus.com (Thomas Hudson)
Date: Sat, 30 Jan 1999 15:11:24 -0500
Subject: Ebow
References: <9902011628.ZM4812@marvin>
Message-ID: <36B3676C.AC4F0942@cygnus.com>

Tom Duff wrote:
> 
> Anybody know what the circuit inside an Ebow looks like?
...
> I want to build an Ebow-controlled zither,

I remember reading an article years ago in Guitar Player
where a guy had built a fretless guitar. The sustain
wasn't so good so he figured out a way to use one of
the existing pickups as a driver. Though I don't know
how this approach would work for multiple strings.

This is also interesting from the viewpoint of adding
distortion and/or filtering to the feedback loop, allowing
different harmonics to evolve over time.

Thomas



From cyborg0 at GlobalEyes.net  Sat Jan 30 22:38:17 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sat, 30 Jan 1999 15:38:17 -0600
Subject: a diode behaving like a cap
References: <ce0b4860.36b365a9@aol.com>
Message-ID: <36B37BC9.C8286975@globaleyes.net>

DCMagnuson at aol.com wrote:

> I just bought a package from Radio Shack on a whim....  so someone's still
> making them.  I don't have any specific use in mind yet, but just grabbed them
> for playing around with.
> 
Theres PLENTY of germanium diodes laying around! I also went to rat
shack and bought some...
U know if radio shack has it, its not going out anytime soon..
rob



From cyborg0 at GlobalEyes.net  Sat Jan 30 23:35:49 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sat, 30 Jan 1999 16:35:49 -0600
Subject: uP programming startup
Message-ID: <36B38945.36AFC7F4@globaleyes.net>

Okay, I want to program PIC chips..
I need a KIT.. a simple KIT, with a book on the commands, maybe a few
simple examples, a programmer, and software..
I HAVE looked at all the commercial sites, but they are soo damn
confusing i want to scream...
Im soo irritated by the layout and confusion of some of these sites, it
makes me want to program with an SBC again and just do straight
assembler with a 6800..

Someone help me out here.. BTW, I only have about $100 bux to spend..

Rob



From dave.halliday at greymatter.com  Sun Jan 31 00:49:28 1999
From: dave.halliday at greymatter.com (Dave Halliday)
Date: Sat, 30 Jan 1999 23:49:28 GMT
Subject: uP programming startup
Message-ID: <9901301642461735@greymatter.com>

>     Okay, I want to program PIC chips..
>     I need a KIT.. a simple KIT, with a book on the commands, maybe a few
>     simple examples, a programmer, and software..
>     I HAVE looked at all the commercial sites, but they are soo damn
>     confusing i want to scream...
>     Im soo irritated by the layout and confusion of some of these sites, it
>     makes me want to program with an SBC again and just do straight
>     assembler with a 6800..
>      
>     Someone help me out here.. BTW, I only have about $100 bux to spend..



Point your browser to www.dontronics.com

Also, suffer through www.microchip.com website because they have a 
load of excellent programming software, code snippets and tips.  Lousy
web site though...

See if a local library has back issues of Circuit Cellar - there was 
a DIY PIC programmer that ran off your paralell port and was pretty 
cheap to build - they offered the board plus programmed chip for about 
$40 if I remember correctly.


I have spent a lot of time with the Intel 8051 series and the PICs are 
a load of fun - well thought out!


--- Via Silver Xpress V4.4 [Reg]



From afas at git.com.au  Sun Jan 31 04:30:11 1999
From: afas at git.com.au (geoffery francis james)
Date: Sun, 31 Jan 1999 11:30:11 +0800
Subject: CV TO MIDI
Message-ID: <199901310331.LAA21137@defiant.git.com.au>

does anyone know of any diy projects for a cv to midi.
thanks in advance
geoff james



From gerryd at ntx-tech.com  Sun Jan 31 05:10:41 1999
From: gerryd at ntx-tech.com (Gerry Dahl)
Date: Sat, 30 Jan 1999 22:10:41 -0600
Subject: [AH] CV TO MIDI
References: <199901310331.LAA21137@defiant.git.com.au>
Message-ID: <36B3D7C1.6C2C@ntx-tech.com>

geoffery francis james wrote:
> 
> does anyone know of any diy projects for a cv to midi.
> thanks in advance
> geoff james

One Answer........PAIA

www.paia.com
midi to cv8



From ka4hjh at gte.net  Sun Jan 31 06:33:00 1999
From: ka4hjh at gte.net (KA4HJH)
Date: Sun, 31 Jan 1999 00:33:00 -0500
Subject: uP programming startup
In-Reply-To: <36B38945.36AFC7F4@globaleyes.net>
Message-ID: <v04011701b2d998a2dd4f@[153.37.233.119]>

>Okay, I want to program PIC chips..
>I need a KIT.. a simple KIT, with a book on the commands, maybe a few
>simple examples, a programmer, and software..
>I HAVE looked at all the commercial sites, but they are soo damn
>confusing i want to scream...
>Im soo irritated by the layout and confusion of some of these sites, it
>makes me want to program with an SBC again and just do straight
>assembler with a 6800..
>
>Someone help me out here.. BTW, I only have about $100 bux to spend..

Check out this site:

http://www.circellar.com/

Call them on the phone and beg for a free trial issue of Circuit Cellar Ink
if you can't find it locally. One issue worth of ads will set your brain on
fire. Go through back issues of Electronics Now (formerly
Radio-Electronics)--they've had lots of cheap PIC (and other) burners in
the last few years. Microcomputer Journal had a of lot of good stuff too
but it's been on the skids for a while now. And of course they're always
Nuts and Volts.

Lucid Technologies has an interesting universal burner but the DNS comes
back bad--they may have moved:

http://www.cs.com/lucid/

Terry Bowman, KA4HJH
"The Mac Doctor"



From budweiser at ozemail.com.au  Sun Jan 31 08:26:52 1999
From: budweiser at ozemail.com.au (Budweiser [FTS])
Date: Sun, 31 Jan 1999 17:56:52 +1030
Subject: 606 problems.
Message-ID: <00f601be4ceb$13b4e3c0$37a66ccb@ppp.ozemail.com.au>

Just been working on some 606 mods, and the machine i was working
has just stopped sequencing. It turns on, but won't do a damn thing.
It won't sync to an external sync 24 input either. It won't change from bank
A to bank B either... something has gone horribly wrong :(

anyone have any experience with the 606 uP?


<bUd>




From chordman at flash.net  Sun Jan 31 08:33:27 1999
From: chordman at flash.net (Scott Gravenhorst)
Date: Sun, 31 Jan 99 08:33:27
Subject: [AH] CV TO MIDI
Message-ID: <199901311636.KAA29244@echo.flash.net>

>>One Answer........PAIA

Umm, not if you read the subject line.  The PAiA MIDI2CV8 is MIDI to CV,
not CV to MIDI.

My understanding of CV -> MIDI is that it is not trivial and there is no
truly 'perfect' method.

-- Scott Gravenhorst
-- RedWebMail by RedStarWare (srg)
-- FatMan Site: www.teklab.com/~chordman
-- Linux Rex, Linux Vobiscum





From pfperry at melbpc.org.au  Sun Jan 31 13:17:58 1999
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 31 Jan 1999 23:17:58 +1100
Subject: soundcard as experimental platform
Message-ID: <1.5.4.32.19990131121758.00d3d2dc@popa.melbpc.org.au>

Has anyone done anything in the way of using an IBM style 
soundcard as the in/out for any kind of diy hack?
It would solve the problem of getting the codec set up..
sounds like a natural for Elektor..

paul perry melbourne australia




From fa_diy at fa.camelot.de  Sun Jan 31 13:18:00 1999
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 31 Jan 1999 14:18:00 +0200
Subject: 606 problems.
In-Reply-To: <00f601be4ceb$13b4e3c0$37a66ccb@ppp.ozemail.com.au>
Message-ID: <79u2MPApHFB@fa.camelot.de>

Hello bud

>It won't sync to an external sync 24 input either. It won't change from bank
>A to bank B either... something has gone horribly wrong :(
>anyone have any experience with the 606 uP?
I don't think it is the uP.

1.) What did you modify?
2.) Do you have schematics?
3.) Are the supply-voltages all ok?
4.) Check the whole board for unwanted shortcuts by solder tin.
5.) Check whether all connectors are put in right position.

Long time ago I did a lot of modifications with 606s. And sometimes I did a  
shortcut somewhere. e.g. I putted single outputs, the device worked fine whne  
it all layed open, but put together the plugs made shortcuts with the  
standing resistors...



Gruss,
 Florian Anwander
-------------------------------------------------------------------------
Maus-Netz: Florian Anwander at M4
Internet:  fa at fa.camelot.de           http://www.camelot.de/~fa/
## CrossPoint v3.11 R ##



From oakley at techrepairs.freeserve.co.uk  Sun Jan 31 17:06:36 1999
From: oakley at techrepairs.freeserve.co.uk (Tony Allgood)
Date: Sun, 31 Jan 1999 16:06:36 -0000
Subject: [AH] CV TO MIDI
Message-ID: <002701be4d34$29bf65c0$e500883e@default>

>One Answer........PAIA

I just bought one of these. Nice kit. Very good instructions. Mind you I
made a few modifications to it. The 4051 de-mpx has 30V across its power
pins, and I don't like that much over voltage. It is only spec'd to take
18V.

Regards,

Tony Allgood, Cumbria, UK

Rack mounted Moog VCF module. Details to be found at...

http://aupe.phys.andrews.edu/diy_archive/schematics/effects/filter.html







From inman at interpath.com  Sun Jan 31 19:00:24 1999
From: inman at interpath.com (inman at interpath.com)
Date: Sun, 31 Jan 1999 10:00:24 -0800
Subject: uP programming startup
References: <36B38945.36AFC7F4@globaleyes.net>
Message-ID: <36B49A38.5E23@interpath.com>

Go to:

http://www.itutech.com/pic-1.htm

For $99, they have a Beginner's Pic PAK that has a fully assembled
programmer WITH power supply, cable, & PIC.  That package includes
Easy PIC'N, a great book for beginners.  They also include a software
program that will load your hex files.

Does it all work?  It is virtually moron-proof.  Unzip the software
(which fits on a 3.5 inch disk and runs under DOS), plug the cable
in the back of your IBM PC, plug the cable into the programmer, put
a PIC in the ZIF socket, plug the power cord into the wall, type
c:\itupic <ENTER> or the directory of your software, type itupic
<ENTER>, choose option # 2 for PIC 16C84 (yes the C84 option programs
the F84), type in the name of your *.asm file <ENTER>, it checks for
the file, press <ENTER>, BOOM!  The PIC is programmed.  You can even
take the PIC out of the ZIF with the circuit hot.

I bought this programmer and I have their programmer and have been
100% satisfied with it.  Also, I note:  although it is an open-faced
electronic circuit, the parts are so well mounted that it will
survive a good deal of rough treatment.  

The only two other things you will need are a copy of MPASM.EXE, the
DOS version or the Windows MPLAB version from Microchip, available free
from www.microchip.com or at many other sites on the web AND a copy of the
PIC 16F84 data book, which covers everything from clock circuit design
to assembly language instructions.

THAT combination will work.


Elliot "I Know a Moron Can Use It because I Tested It Myself"



From will7370 at tao.sou.edu  Sun Jan 31 20:28:03 1999
From: will7370 at tao.sou.edu (Rob & Heather Williams)
Date: Sun, 31 Jan 1999 11:28:03 -0800
Subject: soundcard as experimental platform
References: <1.5.4.32.19990131121758.00d3d2dc@popa.melbpc.org.au>
Message-ID: <36B4AEC3.949E3520@tao.sou.edu>

Not sure if this is what you are looking for, but the new
softsynth demo at the Native Instruments homepage can be
used as an outstanding effects processor AS WELL as allowing
you to virtually build any kind of analog or digital synth
in existence.  The program is called Generator 1.5, and can
be downloaded from their homepage:

http://www.native-instruments.com/

But be warned, once you start playing with this program you
will be hopelessly addicted.  It is the greatest thing I've
ever seen for the PC.

Robert

Paul Perry wrote:
> 
> Has anyone done anything in the way of using an IBM style
> soundcard as the in/out for any kind of diy hack?
> It would solve the problem of getting the codec set up..
> sounds like a natural for Elektor..
> 
> paul perry melbourne australia



From edusilva at bahianet.com.br  Sun Jan 31 21:40:18 1999
From: edusilva at bahianet.com.br (Edu Silva)
Date: Sun, 31 Jan 1999 18:40:18 -0200
Subject: What one can find inside a  well used PC keyboard!!
Message-ID: <199901312045.SAA14746@postman.bahianet.com.br>

> De: BJ <zzynt at swipnet.se>
> Para: diylistan <synth-diy at mailhost.bpa.nl>
> Assunto: What one can find inside a  well used PC keyboard!!
> Data: Segunda-feira, 1 de Fevereiro de 1999 01:48

(snip)

> blah blah blah...
> Imagine what kind of crasy music keyboards one could make
> or what about a user interface in the shape of a half sphere or globe!!!

Seems that someone have had the same idea already...

http://www.si.edu/organiza/museums/nmah/whatisit/ans.htm


Edu

_____________________
ES2 Audio - Som & Luz
Salvador-Bahia-Brasil





From cyborg0 at GlobalEyes.net  Sun Jan 31 22:50:05 1999
From: cyborg0 at GlobalEyes.net (Rob)
Date: Sun, 31 Jan 1999 15:50:05 -0600
Subject: super cheap PIC chip progger
Message-ID: <36B4D00D.4244E64F@globaleyes.net>

For all u ppl who would perhaps like to program a simple midi/cv
converter, midi clockable CV LFOs, etc.. here it is!

http://www.mindspring.com/~covington/noppp/index.html#CIR

Go there, then, go to radio shack and buy all the stuff u need for the
programmer, and code yer head off..
Rob



