From chordman at flash.net  Wed Jul  1 00:38:02 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Tue, 30 Jun 1998 22:38:02 GMT
Subject: LM566CN VCO
In-Reply-To: <199806302045.WAA08214@mailhost.bpa.nl>
References: <199806302045.WAA08214@mailhost.bpa.nl>
Message-ID: <359a6729.81890840@mail.lan>

On Tue, 30 Jun 1998 22:44:11 +0200, Rene Schmitz <uzs159 at uni-bonn.de>
wrote:

>At 23:05 29.06.1998 GMT, you wrote:
>>Well, the spec claims only 10 to 1 freq range.  That's only a little
>>more than 3 octaves.  Unless someone knows of a way to extend this,
>>that seems kind of lame for music.
>It seems that the 566 can be current controlled as well, and in this 
>case the sweep range is more like 1 to 100, I have a schematic for a 
>BBD phaser at hand where this is used. They hold the voltage input at
>some fixed level, and inject the current at pin 6. Hm, sounds as if one 
>could add a simple expo converter and have linear and exponential FM.

I went back to my National book and I see no mention of a change in
it's useful linear range for current control.  Where did you come by
the spec of 1 to 100?  If it is true, it would make an easy to build
VCO, but only if it is linear over that range.  Is it possible that it
will work over that range, but that it might not be linear enough for
music?  If I had one of these, I'd try it now, but I'd rather not buy
any unless I know I can make a VCO that's at least as linear over a
range equivalent to the FatMan's.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From mglnsky at magicnet.net  Wed Jul  1 02:55:34 1998
From: mglnsky at magicnet.net (Mark Glinsky)
Date: Tue, 30 Jun 1998 20:55:34 -0400 (EDT)
Subject: VCA Modules
Message-ID: <199807010055.UAA08496@magicnet.magicnet.net>

Hi - I have two extra Aries AR-316 VCA modules that I'd like
to sell.  Email me for more information - thanks.


_______________________________________________________
 Mark Glinsky -   Orlando, Florida
 Email:                 mglnsky at magicnet.net
 Manual Manor:   http://www.magicnet.net/~mglnsky/msg4.html
 "Be seeing you...."  [ No. 6  -  The Prisoner ]
 "Don't Panic!"   [ HitchHiker's Guide ]
-------------------------------------------------------




From sasami at blaze.net.au  Wed Jul  1 03:14:56 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 1 Jul 1998 11:14:56 +1000 (EST)
Subject: ETI-5600 Q's
Message-ID: <199807010114.LAA04294@blaze.net.au>

My synth is a mixture of Roland, ETI and home grown designs. With the ETI
modules, most of the modules are very easy to interface to others. Some may
require minor modifications. The mixer will work as is. I haven't built the
panner. The 5600 boards are NOT available from RCS Radio. The 4600 boards
are. There are differences. As far as I know, the panner was a 5600 only design.

I have built the sequencer, and a friend built three of them. My only
comment is to replace the 3130 op amps with 3140s. No circuit changes needed
to do this.

Ken

>Given that circuit boards for the ETI synths seem to be readily available,
>I'm wondering if others feel they are acceptable for integration into a
>modular system. In particular, I'm looking at using some of the auxiliary
>boards - the mixers, VC panner, etc - in conjunction with the ASM-1. 
>
>Also, the Web page for the circuit boards (http://www.cia.com.au/rcsradio/)
>mentions an ETI sequencer - but I've never seen an article about it. Anyone
>know much about this?
>
>Jim Johnson 
>Metaphoric Software
>-------------------
>Makers of Techno Toys
>Software for Electronic Music
>http://www.technotoys.com
>info at technotoys.com
>
>
_______________________________________________________________________
Ken Stone   sasami at blaze.net.au  
Catgirl Paradise <http://www.anime.net/~kens/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




From lheckman at juno.com  Wed Jul  1 04:26:57 1998
From: lheckman at juno.com (Lucas A Heckman)
Date: Tue, 30 Jun 1998 21:26:57 -0500
Subject: Snare+ Kit
Message-ID: <19980630.212657.3534.0.lheckman@juno.com>

Hello
Does anyone one have anything to say about the Snare+ Kit from Midwest
Analog Products?  I was thinking of buying one and wanted to see if this
is a kit worth getting.
Lucas

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]



From jamos at technotoys.com  Wed Jul  1 04:38:37 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Tue, 30 Jun 1998 19:38:37 -0700
Subject: ETI-5600 Q's
In-Reply-To: <Pine.SOL.3.91.980630151014.23688A-100000@edmund.cs.andrews.edu>
References: <Pine.SOL.3.91.980630151014.23688A-100000@edmund.cs.andrews.edu>
Message-ID: <199806301938370830.0131C92C@mail.proaxis.com>

Thanks to Tony and all who answered about the sequencer - looks like a good
basic design. 

jim

*********** REPLY SEPARATOR ***********

On 6/30/98, at 3:11 PM, Tony Clark  wrote: 

>> Also, the Web page for the circuit boards
(http://www.cia.com.au/rcsradio/)
>> mentions an ETI sequencer - but I've never seen an article about it.
Anyone
>> know much about this?
>
>   Sure.  You can find it at the DIY Archive at the following URL:
>
>http://aupe.phys.andrews.edu/diy_archive/schematics/sequencers.html
>
>   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!
>------------------------------------'----------------------------------

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com




From shudder at optusnet.com.au  Wed Jul  1 07:51:07 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Wed, 1 Jul 1998 15:51:07 +1000
Subject: [sdiy] The most unique ringmod you've ever seen!!
Message-ID: <3ac7e03c.356d.0@telusplanet.net>

That reply was off list, feel free to post it if you feel others could
benefit from the humour :)
Sean
-----Original Message-----
From: The Peasant <epeasant at telusplanet.net>
To: Sean-E <shudder at optusnet.com.au>; epeasant at telusplanet.net
<epeasant at telusplanet.net>
Date: Monday, 2 April 2001 11:45
Subject: Re: [sdiy] The most unique ringmod you've ever seen!!


>Hi Sean,
>>
>>Great idea Doug, so nifty I think I'll have to try this! I know a shop
>>selling an ice-cream container full of these displays.
>>What's next, a microwave oven VCF? :)
>
>Can't you guys just leave me alone!! Every time I pass a challenge, someone
>has to give me a harder one!  ;-)
>
>Come to think of it, this could be useful for drones, and a magnetron IS a
vacuum
>tube!
>
>Take care,
>Doug





From martin.czech at intermetall.de  Wed Jul  1 08:15:24 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 1 Jul 1998 08:15:24 +0200 (MET DST)
Subject: LDR Properties
Message-ID: <199807010615.IAA10484@window.intermetall.de>

Old databooks are so usefull:

An old Valvo Optoelectronic book came into my hands and
voila there are the answers to my questions:

-most LDR are based on CdS, this means Tmax=70C

-maximum light sensitivity of CdS at 530 nm (blue-green)
 and about 640 nm (orange-red). High performance red leds
 thus are suitable.

-the first order formula for resistance: R2/R1=(E1/E2)^gamma
 and gamma=(log R1- log R2)/(log E2-log E1)
 where E is the light intensity.
 LDRs come with different flavours of gamma.

-temporal behaviour:
 an example for "light-on" shows 
 1ms delay for 1e7 to 1e2 Ohm (5000 lux), it then takes 1s down
 to 20 Ohm
 10ms for 1e7 to 1e3 Ohm (500 lux) , 90ms later it settles at 100 Ohm
 100ms for 10e8 to 1e3 Ohm (50 lux), 900ms later settling to 400 Ohm

 "light-off":
 from 20 Ohm to 1e4 (5000 lux) 100ms, to 1e6 1.5s !
 from 100 Ohm to 1e5 (500 lux) 400ms, to 1e6 1.5s
 from 400 Ohm to 1e5 (50 lux) ~400ms, to 1e6 1.5s

 Time delay for on is much shorter then for off, but 
 the time depends on light intensity, it can be quite fast.
 It takes almost the same time from any "on-state" to 
 "really-off" (1e6 Ohm). 
 
-the light intensity of an led is linear dependend on the 
 forward current, with very good approximation.


The nonlinear time behaviour makes it questionable, if
for example the ldr makes a triangle-sine shaper unneccesary,
or even a quare -tri shaper.

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 q_bot at yahoo.com  Wed Jul  1 08:53:55 1998
From: q_bot at yahoo.com (Andrew Puls Q-Bot Eye)
Date: Tue, 30 Jun 1998 23:53:55 -0700 (PDT)
Subject: Jen SX-2000
Message-ID: <19980701065356.20705.rocketmail@send1c.yahoomail.com>

Hi,
A while ago I was at a music store located up in the top of an old
appartment complex/office building that mainly sells accordians and
other instruments imported from Italy, when I noticed a little
synthesizer.  It is a "Jen" Synthetone SX-2000.  I had never heard of
this company before, but I played around with it and it sounded great!
It had never been used (it had just been sitting up there for all
these years! It still had the owners manual, a booklet with all of the
schematics, and some sheets specially designed for writing down the
patches you create!), and the owner let me take it cheap (and he threw
in a stand for $1). As far as he was probably concearned, at this
point it was just taking up space. My point in writing this message is
actually not to tell you about this great deal and all of my shopping
expieriences (though I know you care (you know sarcasm when you read
it don't you?)), but rather to inquire about the of Jen company and
any insights to the years of production, the number of them made, and
the value of this synth. I know that some of you guys have been around
for a while and may have been around when this company was in
existance (if it isn't now), because I probably wasn't even born yet!

Thanks in advance for any information.
==
Q-Bot, Andy Puls
q_bot at yahoo.com

["""]      ["""] ["""] """"""
[   ] ~~~  [ _ / [   ]   []
[  \]      [   \ [   ]   []
[___\      [___] [___]   []
_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com




From media at mail1.nai.net  Wed Jul  1 09:16:34 1998
From: media at mail1.nai.net (media at mail1.nai.net)
Date: Wed, 1 Jul 1998 03:16:34 -0400 (EDT)
Subject: EML-300 Sch.
In-Reply-To: <3.0.5.32.19980618095638.007a2100@192.168.210.18>
Message-ID: <v03130305b1bf39fbaa64@[209.150.33.195]>

At 9:56 AM -0500 06/18/98, Bill Layer wrote:
>Does anyone have a schematic for an EML-300 Manual controller? (or for that
>matter, the EML-200) Mine has been real flaky ever since I've had it.

I do not have complete schematics, but I do have the schematics for a large
number of EML circuits used in the 200 and 300.

Send me private email as to what circuits you need and I'll go through my
files.

On a related note, does anyone have schematics for the EML-100 filter??  I
need those.

PEACE OUT :)
MARK






From media at mail1.nai.net  Wed Jul  1 09:16:39 1998
From: media at mail1.nai.net (media at mail1.nai.net)
Date: Wed, 1 Jul 1998 03:16:39 -0400 (EDT)
Subject: Capacitor FAQ?
In-Reply-To: <3.0.5.32.19980618095638.007a2100@192.168.210.18>
Message-ID: <v03130307b1bf3b5cfd8a@[209.150.33.195]>


Just to let everyone know, I haven't died or anything. I am still waiting
on the Arizona Capacitor catalog.  I've called twice already.  Last I heard
they are putting a UPS trace on it :/

On a related note, is the list currently being archived??

PEACE OUT :)
MARK






From media at mail1.nai.net  Wed Jul  1 09:16:58 1998
From: media at mail1.nai.net (media at mail1.nai.net)
Date: Wed, 1 Jul 1998 03:16:58 -0400 (EDT)
Subject: Adding a MIDI Thru
In-Reply-To: <Pine.HPP.3.95.980622131844.7752E-100000@bay.cs.brandeis.edu>
References: <19980622153855.21758.qmail@hotmail.com>
Message-ID: <v0313030cb1bf4253a077@[209.150.33.195]>

At 1:22 PM -0400 06/22/98, Andrew Schrock wrote:
>
>Generally speaking I think the longest you can use midi
>cabling before some deterioration is 6 meters. (somebody tell me if i'm
>way off base here)

The MIDI spec states that cables shouldn't be longer than 15 meters.

(well, you asked me to tell you!)

Anyway, as far as I know, to add on a MIDI Thru you tap the signal after
the opto-isolator for the MIDI In (the same signal going to the UART).
This is then buffered (through two inverters in series or an op-amp or
somesuch) and connected to pin 5 with a 220 ohm resistor, pin 4 is
connected to +5V with another 220 ohm resistor, pin 2 is grounded.  As in
all MIDI connections, pins 3 and 1 are unused.

PEACE OUT :)
MARK










From media at mail1.nai.net  Wed Jul  1 09:17:02 1998
From: media at mail1.nai.net (media at mail1.nai.net)
Date: Wed, 1 Jul 1998 03:17:02 -0400 (EDT)
Subject: More MIDI stuff
In-Reply-To: <Pine.PMDF.3.95.980624113926.971488A-100000@OBERLIN.EDU>
Message-ID: <v0313030db1bf48d72843@[209.150.33.195]>

At 11:47 AM -0400 06/24/98, Silence wrote:
>
>Also, the MIDI spec 1.0 says that the maximum recommended length for
>a MIDI cable is 50'.

Well, 49' if you convert it from metric :)

>After this, the capacitance of the cable rounds off the pulse edges too
>much to be useful.  When chaining together devices, the problem is less
>with losing data, than it is with the time delay becoming very noticable,
>i.e. the first synth sounds 50 milliseconds before the last synth, which
>is a VERY audible differnece.

No, the problem is losing data.  The only delay from a MIDI Thru is from
the optoisolator.  It is about 3uS.  To get a delay of 50mS you would have
to daisy chain over 16,000 MIDI Thrus.  Not even Vince Clarke has that much
gear :)

The limit on the number of MIDI Thru's is from distortion of the signal.
The rise of an optoisolator is only 3uS but it still isn't instantaneous.
So the cumulative effect of a number of optoisolators will shorten the time
of the individual bits eventually causing data to be lost.

PEACE OUT :)
MARK













From pfperry at melbpc.org.au  Wed Jul  1 10:34:12 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 1 Jul 1998 18:34:12 +1000 (EST)
Subject: ETI-5600 Q's
Message-ID: <1.5.4.16.19961123010934.2f678cd8@popa.melbpc.org.au>

At 08:20 AM 30/06/98 -0700, Jim Johnson" <jamos at technotoys wrote:
>Given that circuit boards for the ETI synths seem to be readily available,
>I'm wondering if others feel they are acceptable for integration into a
>modular system. In particular, I'm looking at using some of the auxiliary
>boards - the mixers, VC panner, etc - in conjunction with the ASM-1. 
>
>Also, the Web page for the circuit boards (http://www.cia.com.au/rcsradio/)
>mentions an ETI sequencer - but I've never seen an article about it. Anyone
>know much about this?

Jim, I can't recommend the ETI ckts..
they just 'look wrong' too.. not many success stories in this field.
Really, you'd be much better using more recent ckts from the net eg from
Tomg. And, there are plenty of mixer ckts out there.
I have a (non-working) ETI sequencer, and have seen ones that do work.
It's just a standard ring thing with leds and pots, nothing flash.
The fact that the boards are available, while a minor miracle, is not
justification enough in my opinion.




From pfperry at melbpc.org.au  Wed Jul  1 10:34:28 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 1 Jul 1998 18:34:28 +1000 (EST)
Subject: e*ectronotes replacements arrived
Message-ID: <1.5.4.16.19961123010950.2f674af6@popa.melbpc.org.au>

Well after doing what I should have done earlier & contacting BH
he has sent the missing box of e*ectronotes..
mailed 26JuneUSA, arrived 1July Australia. 
So all well that end well, except I should make a grovelling
apology for any unkind thoughts I might have had re speed, efficiency 
etc of the EN enterprise & redirect them to the postal system.. though I
have never had any problems before with airmail US to Aust.

OK now to forget all this grief and start soldering!
And thanks to everyone who contacted me publicly and privately on this,
esp Thomas Henry at Midwest Analog Products.

paul perry melbourne australia  




From Juergen.Haible at nbgm.siemens.de  Wed Jul  1 10:54:14 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 1 Jul 1998 10:54:14 +0200 
Subject: AW: LDR Properties
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58278A9C4@nbgm336a.nbgm.siemens.de>

	>The nonlinear time behaviour makes it questionable, if
	>for example the ldr makes a triangle-sine shaper unneccesary,
	>or even a quare -tri shaper.

When I built my clone of the PS-3100 Resonator, I tried different
modulation circuits. I included a variable slope triangle/saw generator,
and an OTA-based sine shaper.
Results were:
* Switching from triangle to sine does not make any noticable difference.
* The effect of variable rise and fall times is still noticable, but only
with
   rather slow modulation rates.

JH.



From jamos at technotoys.com  Wed Jul  1 17:28:57 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Wed, 01 Jul 1998 08:28:57 -0700
Subject: ETI-5600 Q's
In-Reply-To: <1.5.4.16.19961123010934.2f678cd8@popa.melbpc.org.au>
References: <1.5.4.16.19961123010934.2f678cd8@popa.melbpc.org.au>
Message-ID: <199807010828570140.03F32481@mail.proaxis.com>

>Jim, I can't recommend the ETI ckts..
>they just 'look wrong' too.. not many success stories in this field.
>Really, you'd be much better using more recent ckts from the net eg from
>Tomg. And, there are plenty of mixer ckts out there.
>I have a (non-working) ETI sequencer, and have seen ones that do work.
>It's just a standard ring thing with leds and pots, nothing flash.
>The fact that the boards are available, while a minor miracle, is not
>justification enough in my opinion.

Thanks for the tips. This brings me to a bit of a soap-box point, however -
while there may be a ton of schematics out there, there are damn few
circuit boards available for anything - the ASM-1 is of course the notable
exception. I'm leery of building stuff on protoboard (maybe I shouldn't be,
but the crappy results I got when trying to build a vocoder many years ago
left a bad taste in my mouth.) 

I think it's fantastic that people like Tomg and Juergen Haible are giving
their circuit designs to the world.. but given the difficulty of a)
building (good-looking) front panels and b) hand-wiring (reliable, clean)
circuits, I despair of ever having my own Interpolating Scanner.

But then again - a mixer ain't rocket science. So maybe, after my life
settles down (long story) and I get an ASM-1 under my belt, I'll try
hand-wiring some simple circuits and see how they work out.

And I was not impressed with the ETI sequencer - as you said, pretty
standard. I guess after working with Seq-303 for so long, I expect a little
more out of an analog sequencer .. :')

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com



 

*********** REPLY SEPARATOR ***********

On 7/1/98, at 6:34 PM, Paul Perry  wrote: 

>At 08:20 AM 30/06/98 -0700, Jim Johnson" <jamos at technotoys wrote:
>>Given that circuit boards for the ETI synths seem to be readily
available,
>>I'm wondering if others feel they are acceptable for integration into a
>>modular system. In particular, I'm looking at using some of the auxiliary
>>boards - the mixers, VC panner, etc - in conjunction with the ASM-1. 
>>
>>Also, the Web page for the circuit boards
(http://www.cia.com.au/rcsradio/)
>>mentions an ETI sequencer - but I've never seen an article about it.
Anyone
>>know much about this?
>
>Jim, I can't recommend the ETI ckts..
>they just 'look wrong' too.. not many success stories in this field.
>Really, you'd be much better using more recent ckts from the net eg from
>Tomg. And, there are plenty of mixer ckts out there.
>I have a (non-working) ETI sequencer, and have seen ones that do work.
>It's just a standard ring thing with leds and pots, nothing flash.
>The fact that the boards are available, while a minor miracle, is not
>justification enough in my opinion.



From rams0046 at tc.umn.edu  Wed Jul  1 19:54:48 1998
From: rams0046 at tc.umn.edu (JOSEPH S RAMSTROM)
Date: Wed, 1 Jul 1998 12:54:48 -0500
Subject: ahhhhhhhhhhhhhhhhhh
Message-ID: <359a77e33992496@mhub2.tc.umn.edu>

take me offf!!!!  :(





From blacet at metro.net  Wed Jul  1 20:13:18 1998
From: blacet at metro.net (John Blacet)
Date: Wed, 01 Jul 1998 18:13:18 +0000
Subject: Blacet Research News
Message-ID: <359A7C3E.3B42@metro.net>

Hi Folks:
Sales of the DSC and other items have been brisk; thanks to all of you
that placed orders!

A couple of interesting reviews have been done on the DSC and they are
linked on the site.

We have so far avoided any significant delivery delays thanks to a hard
working crew and excellent part vendors.

On the new product front, we have two power supplies with some
interesting power distribution features. Check them out. The PS-100 is
on sale the rest of this month for only $15 when ordered with a Dark
Star!

Coming in a few weeks is Klang Werk, a feature packed, very high quality
ring modulator that includes a built-in voltage controllable sine wave
carrier source with voltage controlled waveform morphing. Other features
include an envelope follower and variable gain on the signal and carrier
inputs to allow maximum noise free performance.

If you would be interested in Klang Werk, let us know and we will put
you on the waiting list.

Finally, a bit of a problem has occurred with our "Join our Mailing
List..." form program over the past month which resulted in some people
not getting put on our list. This was due to a glitch at our ISP that
took forever to fix. This is part of the reason this is going out over
the analog and DIY lists. If you filled out the form in the last month
or so, you may want to do it again...sorry!


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



From svetengr at earthlink.net  Wed Jul  1 21:04:55 1998
From: svetengr at earthlink.net (Eric at Svetlana Electron Devices)
Date: Wed, 01 Jul 1998 12:04:55 -0700
Subject: tube synths /VCA
Message-ID: <199807011906.MAA25404@cuckoo.prod.itd.earthlink.net>


>Would that mean that I could use a transformerless voltage multiplier as 
>supply for your circuits? (A high frequency square fed into a poweramp and 
>then into a diode/cap cascade)
>Would you recommend that or a switcher? 

Yes. Such devices (using step-up transformers) are made commercially
by firms such as Pico Electronics and ERG. Expensive, though. 
I believe the Paia Tubehead makes its 40v plate supply with such a scheme.

You could just use a 555 oscillator and a small, cheap radio-type audio
output
transformer to get HV--the kinds used in pocket radios are usually 100-500
ohms
to 8 ohms--drive the 8-ohm secondary from the 555 output
(perhaps using a power transistor or LM386 as a buffer), take the
voltage off the primary, and rectify and filter it. Should be good for 1 or
2
milliamps. (Have to breadboard the circuit--there are losses in 
such transformers which make the final voltage difficult to determine.)

>How much current does your VCA draw at 50-100V?

Less than 0.5 mA. At 250v it will draw about 1.5 mA.

>I thought pentodes need a high voltage on the screen grid?

Huh? The screen voltage MUST always be LESS than the plate
voltage! if not, the screen will draw all the plate current,
possibly (in power tubes) causing damage or (in small tubes
like we are talking about here) screwing up the tube's operation.

The gain of a pentode is controlled by the screen-grid voltage.
If it is zero, the gain will be zero. If you set it to about
half the plate voltage, the gain will be maximum--from 100
to as much as 500 depending on the device.

Try it, Rene..........



From sebsi23 at hooked.net  Wed Jul  1 21:13:59 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Wed, 01 Jul 1998 12:13:59 -0700
Subject: PAIA modules due in August
Message-ID: <199807011913.MAA29695@mom.hooked.net>

just got off the phone with John Simonton of PAIA, who reports that the
redesigned modules (dual vco, dual vcf, dual just about everything!) are
coming along and should be available in August. 


Matt Wilson, Odyssey Studios
               on the web: www.wenet.net/~sebsi23
                          on the phone: 415 675-4886
                                    on the email: sebsi23 at hooked.net				
                            




From uzs159 at uni-bonn.de  Wed Jul  1 22:40:26 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 01 Jul 1998 22:40:26 +0200
Subject: LM566CN VCO
Message-ID: <199807012041.WAA25531@mailhost.bpa.nl>

At 22:38 30.06.1998 GMT, you wrote:
>On Tue, 30 Jun 1998 22:44:11 +0200, Rene Schmitz <uzs159 at uni-bonn.de>
>wrote:
>
>>At 23:05 29.06.1998 GMT, you wrote:
>>>Well, the spec claims only 10 to 1 freq range.  That's only a little
>>>more than 3 octaves.  Unless someone knows of a way to extend this,
>>>that seems kind of lame for music.
>>It seems that the 566 can be current controlled as well, and in this
>>case the sweep range is more like 1 to 100, I have a schematic for a
>>BBD phaser at hand where this is used. They hold the voltage input at
>>some fixed level, and inject the current at pin 6. Hm, sounds as if one
>>could add a simple expo converter and have linear and exponential FM.
>
>I went back to my National book and I see no mention of a change in
>it's useful linear range for current control.  Where did you come by
>the spec of 1 to 100?  If it is true, it would make an easy to build
>VCO, but only if it is linear over that range.  Is it possible that it
>will work over that range, but that it might not be linear enough for
>music?  If I had one of these, I'd try it now, but I'd rather not buy
>any unless I know I can make a VCO that's at least as linear over a
>range equivalent to the FatMan's.

The range is not in the spec, I've looked there myself, and it says only 1 to 10
with voltage control, but the pin 6 is actually a current input.
In the BBD phaser where I saw this, the VCO had a frequency  range of 10kHz
to 800kHz
not 1 to 100 but close.
Maybe I've some 566s arround here and give it a try...

-Rene
=(uzs159 at uni-bonn.de)========================
             ,          : 
|") [" |\ | ["          :   This space 
|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From tboy at firebottle.com  Thu Jul  2 00:42:06 1998
From: tboy at firebottle.com (Steve Morrison)
Date: Wed, 1 Jul 1998 15:42:06 -700
Subject: LM566CN VCO
In-Reply-To: <199807012041.WAA25531@mailhost.bpa.nl>
Message-ID: <199807012142.PAA25951@mars.aros.net>

John Simonton of PAiA once did a "lab notes" column in Polyphony 
Magazine on the subject of improving the performance of the 566 
as a VCO. Perhaps we could prevail on 'el honcho' for some comments?
How 'bout it John?

--tboy



From magnus at analogue.org  Thu Jul  2 01:20:58 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 02 Jul 1998 01:20:58 +0200
Subject: more frequency tracking.. 
In-Reply-To: Your message of "Tue, 16 Jun 1998 18:09:47 -0700 (PDT)"
References: <199806170109.SAA11948@smtp.ucsd.edu>
Message-ID: <199807012320.BAA09006@piraya.electrum.kth.se>

>>>>> "ED" == Ethan Duni <eduni at ucsd.edu> writes:

This is a little late reply (posted in 16/6) but I have been out of
luck with my Internet line so...

 ED> anyone have any thoughts on using a PLL to extract a clean sine from an
 ED> arbitrary signal and then running that across a series RC, tapping off of
 ED> one of the components then running that to a buffer and then rectifying and
 ED> filtering to get a frequency tracking CV?  how large a delay is usually
 ED> introduced in a PLL before the VCO matches the input frequency?  which PLL's
 ED> have the lowest delay?

The idea of using PLL to have a VCO track along isn't new, the Moog 921
oscillators have a PLL mode.

I am not really sure that I get your idea of what you want to do, but
I can say something about PLLs. First of all is there a wide class of
PLLs each having their usefull properties, they can have diffrent lock
range, track range etc. The actual lock time wil vary greatly with
factors such as which phase detector and which loop filter is being
used just as well as which input signal is you trying to lock. There
are signal situations that a PLL may chase forever... if your signal
will have a too step frequency change per time unit may a PLL not be
able to lock it or even track it. You can unlock a PLL with a quick
chirp or frequency step.

The type of filter will also greatly change these properties.

A PLL may be of diffrent degrees, depending on how many poles the
system contains. The simple rule for counting degree is that there is
one pole in the VCO and all the others is in the loop filter.

A first degree is pretty useless for most applications, it has no loop
filter and will make abrupt jumps and has no memory what so
ever. Whenever there is a phase difference it will cause a jump on the
output, not very neat.

A second degree PLL is very common, the loop filter is usually either
a RC-lowpass or a RCR-lowpass lag filter. There is many good books
describing these. The second degree PLLs can do stuff like frequency
multiplication, tracking, FM-demoduling, phase-jitter swallowing etc.
The properties is also governed by the phase comparator used, you may
use 4-quadrant multipliers, XOR gate, state-machine (the 4046) or
JK-flipflop phasedetectors, each with their own property. The
selection of the phase detector may be as crusuial as correctly
dimensioning the loop filter.

Higher degrees PLLs are uncommon but have their own right in various
applications (like moving and accelerating GPS receivers).

Dimensioning a PLL can be a hairpulling experience until one get the
basics straight... but it does not need to be too hard to get up and
playing. Take a 4046 (or a 74HC4046) build a simple RC filter with a
tau of say 20 ms to start with, hook the 4046 up according to the
datasheet, use either of the phase detectors (the 74HC4046 has a
third, a JK-flipflop) and start of with the internal VCO set for audio
range and start playing with it. The simple RC filter will have a
large locking range.

The 4046 is a very simple and easy to use standard PLL for a low cost,
it is a great tool to start fooling around on and you may dump the VCO
on it if you feel like it.
There is a neat little thing in it worth using, the loopfilter output
is being feed to the input of the VCO which starts of with a MOSFET
follower that has an input impedance at about 1 Tohm and a output
impedance way down, so you will not need to worry much about how you
load your passive filter or even much on how you select components.
You may also have an output being taped wiether or not you are using
the internal VCO. When you use the 4046 as a FM demodulator you tap
the output signal at the output of this buffer, most usefull.

Cheers,
Magnus




From e93_mda at drum.it.kth.se  Thu Jul  2 01:40:50 1998
From: e93_mda at drum.it.kth.se (Magnus Danielson)
Date: Thu, 02 Jul 1998 01:40:50 +0200
Subject: OT: A diffrent fluid studio incident
In-Reply-To: Your message of "Wed, 17 Jun 1998 07:19:09 PDT"
References: <19980617141909.28658.qmail@hotmail.com>
Message-ID: <199807012340.BAA09232@piraya.electrum.kth.se>

>>>>> "NT" == Neo Tribal <neo_tribal at hotmail.com> writes:

 >> Coke should be a drink, not a sudden addition to once's electronic
 >> gizmos. I think the same goes for beer...

 NT> Tell me about it... I spilled beer in my CR-1604vlz once... not just ANY 
 NT> beer - I'm talking GUINNESS... ick! It took hours to clean out that 
 NT> unit... A big lesson was learned... *sheepish grin*

Next time you feel like geting rid of some GUINNESS, dont feed your
CR-1604vlz with it, feed me with it. I am sure that you agree that I
have a much more developed apprechiation for it than your 1604!

Cheers,
Magnus



From magnus at analogue.org  Thu Jul  2 02:13:36 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 02 Jul 1998 02:13:36 +0200
Subject: O-scope question for you old EE's
In-Reply-To: Your message of "Wed, 17 Jun 1998 10:05:21 -0400"
References: <81A062BC5305D111A9D700805F065968816190@maildepo.sc.siemens.com>
Message-ID: <199807020013.CAA09552@piraya.electrum.kth.se>

>>>>> "LC" == List, Christopher <Chris.List at sc.siemens.com> writes:

 LC> Quick tool question for you - 
 LC> If you were going to spend $450 on a scope, would you get a brand new
 LC> 20MHz, no frills, LG-Precision or BK-Precision, or would you get an
 LC> older used 50 or 100 MHz Tek or HP with delayed sweep or some other
 LC> nifty things?

It depends on the shape of it, a good shape HP or Tektronix with the
right modules is a good investment. I recon that you would not need to
spend all the $450 on a old scope to get a good one, but you could
surely spend the money on a good set of probes, since these will wear out.

 LC> Any thoughts and/or experiences to share?

Channels, 2 is a minimum, 4 is a releif (I have a 4-channel 50 MHz Tek
547 with dual timebase and delayed sweep that I bought for $25)
anything above that is a blessing.

Speed. You can't get enought of it... well, 50 MHz will certainly be
well enougth for normal audio (and some but not all of the digital one
encounters).

For older scopes there is a few things to consider:

Shape of pots and switches. Nothing will be such a direct anoying
factor as these failing on you. Consider the feasability of having
them fixed or replaced. Some of the switches for a Tectronix is not
easily replaced since they have the full set of adjustable damping
mounted in the rotating part of the switch.

Feasability of getting (good) spare parts. Replacement of CRT and
tubes will eventually become unavoidable and the correct parts is more
or less crutial here. For tubes you may find good replacements I
guess. Otherwise it is the standard refresh mantras such as checking
the electrolyts etc. Getting hold of Service manuals is a great
advantage and try to ensure to get original manuals when possible, the
photos and commented schematics can be most enlightning sometimes.
The Tectronix Service manuals that I have is really high quality stuff
and it is a great enjoyment reading them.

Heat dispantion, weight and space may be issues to consider. My 547 is
a large, heavy and very power-to-heat-efficient blue thing to use, it
works as a tool with its flaws but I rather work with a modern scope
most of the time if available.

Modules. Most of the scopes that you encounter have fixed input
modules, there are more expensive scopes which uses modules that can
have interesting extra modules. I have for instance a couple of
modules that's coarsest scale is 10 mV/cm and then digs deeper down,
this is certainly something that many scopes can't deal with and is
great for noise analysis. The lack of lower end can be quite anoying,
especially in audio when one have large dynamic ranges. Then there is
diffrential modules etc. Some of the diff modules require a diff
probe, be sure to lay your hands on them!

A function that you would not like to be without is XY plot mode, it
is more usefull than one might think. If a scope also has a I/V figure
tracker (easilly built) you have a even more powerfull tool. An I/V
tracker is a very easy way of comparing a point between a working and
a failing board, you may see broken inputs due to ESD etc. However,
few scopes come with this property (the I/V). Few scopes lack XY mode
thought (I have one which is nothing but XY, it does not even have
variable input sensitivity).

Cheers,
Magnus




From magnus at analogue.org  Thu Jul  2 03:50:30 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 02 Jul 1998 03:50:30 +0200
Subject: ASM1 cap
In-Reply-To: Your message of "Fri, 19 Jun 1998 05:58:47"
References: <3.0.2.16.19980619055847.22373c3c@mail.internet-zahav.net>
Message-ID: <199807020150.DAA10775@piraya.electrum.kth.se>

>>>>> "GM" == Gur Milstein <gur-m at internet-zahav.net> writes:

 GM> helo every body.
 GM> i'm starting thees days to colecte the parts
 GM> needed for my ASM'S pcb's to come.
 GM> my ferst ASM i build have some leaking and GND problems ,i think
 GM> it may be because of bad cap in the vco's ,lfo.....
 GM> so i would like to ask you guys
 GM> what kind of cap are recomended for use in the
 GM> folwing moduls (not bypass cap):
 GM> NOISE
 GM> LFO
 GM> VCA
 GM> ADSR
 GM> VCF
 GM> allso any other importenet info on how to make the ASM1
 GM> as professunal as can be is welcome ?

I used polypropylene for all caps except where I could not get
it. Lowleakage and low dielectric absorbtion (go read Bob Peace's article!).

I used MAT-02s and I used 20-turn trimmers all over. I used 1% resistors.

I cleaned the PCB thoroughly after soldering to avoid leackage on the
PCB.

I used silver mixed tin.

As allways handle all semiconductors with care as regarding to ESD
troubles, this also accounts for the stuffed PCB.

Care in craftmansship will also be important.

PS. I have noticed that the VCOs will generate a burst as the reset
period ends, an cap right over the LM311 should maybe cure it
somewhat.

Cheers,
Magnus



From cyborg0 at GlobalEyes.net  Thu Jul  2 04:07:24 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Wed, 01 Jul 1998 21:07:24 -0500
Subject: tube synths /VCA
References: <199807011906.MAA25404@cuckoo.prod.itd.earthlink.net>
Message-ID: <359AEB5C.80DD34C@globaleyes.net>

WOW!!! thanx for the insights!! gotta go look into the giant cabinet o
old tubes at work and get something going..
rob

Eric at Svetlana Electron Devices wrote:
> 
> >Would that mean that I could use a transformerless voltage multiplier as
> >supply for your circuits? (A high frequency square fed into a poweramp and
> >then into a diode/cap cascade)
> >Would you recommend that or a switcher?
> 
> Yes. Such devices (using step-up transformers) are made commercially
> by firms such as Pico Electronics and ERG. Expensive, though.
> I believe the Paia Tubehead makes its 40v plate supply with such a scheme.
> 
> You could just use a 555 oscillator and a small, cheap radio-type audio
> output
> transformer to get HV--the kinds used in pocket radios are usually 100-500
> ohms
> to 8 ohms--drive the 8-ohm secondary from the 555 output
> (perhaps using a power transistor or LM386 as a buffer), take the
> voltage off the primary, and rectify and filter it. Should be good for 1 or
> 2
> milliamps. (Have to breadboard the circuit--there are losses in
> such transformers which make the final voltage difficult to determine.)
> 
> >How much current does your VCA draw at 50-100V?
> 
> Less than 0.5 mA. At 250v it will draw about 1.5 mA.
> 
> >I thought pentodes need a high voltage on the screen grid?
> 
> Huh? The screen voltage MUST always be LESS than the plate
> voltage! if not, the screen will draw all the plate current,
> possibly (in power tubes) causing damage or (in small tubes
> like we are talking about here) screwing up the tube's operation.
> 
> The gain of a pentode is controlled by the screen-grid voltage.
> If it is zero, the gain will be zero. If you set it to about
> half the plate voltage, the gain will be maximum--from 100
> to as much as 500 depending on the device.
> 
> Try it, Rene..........



From Juergen.Haible at nbgm.siemens.de  Thu Jul  2 11:23:22 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 2 Jul 1998 11:23:22 +0200 
Subject: AW: more frequency tracking.. 
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582798431@nbgm336a.nbgm.siemens.de>

	>The idea of using PLL to have a VCO track along isn't new, the Moog
921
	>oscillators have a PLL mode.

Great surprise for me. Guess I have to look at these schemos again ...

	>A first degree is pretty useless for most applications, it has no
loop
	>filter and will make abrupt jumps and has no memory what so
	>ever. Whenever there is a phase difference it will cause a jump on
the
	>output, not very neat.

I have to disagree with "pretty useless", because I worked with
the first degree PLL in my diploma thesis (I hope this is the right
word), and this PLL made a hell of a good demodulator for
FM radio. BTW, it can be shown that the schmitt trigger / integrator
triangle / square oscillator that is widely used in LFOs will
act as 1st order zero crossing PLL when you add one more resistor
to the integrator input summing node and use this to feed in your
signal. The ratio between the two resistors will then set the
hold range of the PLL. I mention this, because I remember seeing
a similar circuit in Buchla's famous noise and random module,
but I may be wrong here. (Have to look again.)
As for no memory: If there is a pole, there must be some memory,
and while there is no capacitor in the (nonexisting) loop filter, there
is surely one in the VCO.

So I couldn't resist to comment here. Great post, nevertheless!

JH.




From gur-m at internet-zahav.net  Thu Jul  2 10:15:37 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Thu, 02 Jul 1998 10:15:37
Subject: saw to tri to sine
Message-ID: <3.0.2.16.19980702101537.21071592@mail.internet-zahav.net>

helo every body.
i want to convert  a saw wave to tri and to sine.
i read Gene's experements with a npn to convert
a saw to tri,0v-5v saw in
gut a 2v-4.5v tri out ,so what i ask
is how to make the tri output 0v-5v ,any thoghts ?
and allso how to then make frome the tri a sine wave ?

thanx
Gur Milstein



From jocke at netcontrol.fi  Thu Jul  2 13:12:34 1998
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Thu, 2 Jul 1998 14:12:34 +0300 (EET DST)
Subject: Battery Backup for CMOS RAM
In-Reply-To: <9806298991.AA899105417@ccgate.cochlear.com.au>
Message-ID: <Pine.LNX.3.95.980702132725.11437A-100000@home.netcontrol.fi>

I promised to follow up on this thread -- I've now got some circuit
examples on the web.

The first circuit <http://www.netcontrol.fi/~jocke/circuits/bbkp1.gif>
works as follows:

In normal operation, with +5V present and the -RESET signal pulled
high (inactive), Q1 conducts, thus activating the Chip Select signal
-RAMCS (active low). This also activates Q2 which pulls the RAM
supply +RAMVDD close to +5V. Since +RAMVDD is higher than the battery
voltage, diode D1 is "off".

When the -RESET signal (which should preferrably be driven by an
undervoltage detector) is taken low (active), Q1 and Q2 are
deactivated, and +RAMVDD falls to the battery voltage (approx.)
as D1 starts to conduct. As soon as Q1 stops conducting, -RAMCS
is pulled high by R1, so as to ensure that the RAM chip enters
the standby mode, and that stored data isn't affected by spurious
write pulses.

This circuit works in applications where the RAM's Chip Select
can remain activated in normal operation. If, however, the Chip
Select signal has to be controlled by the processor (or address
decoding circuitry), an OR-gate can be added as shown in
<http://www.netcontrol.fi/~jocke/circuits/bbkp2.gif>. Note
that the OR-gate package has to be powered from the backed-up
+RAMVDD line.

The capacitor and transistors should have low leakage specs -- I'm
not sure how the 2N3904/3906 shown rate in this respect, but I've
used this circuit with good results.

-joachim





From aschrock at cs.brandeis.edu  Thu Jul  2 16:35:48 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Thu, 2 Jul 1998 10:35:48 -0400 (EDT)
Subject: somewhat OT: OB problems
In-Reply-To: <Pine.SGI.3.95.980629102637.11353A-100000@pearl.cs.brandeis.edu>
Message-ID: <Pine.SGI.3.95.980702103429.26383D-100000@pearl.cs.brandeis.edu>

On Mon, 29 Jun 1998, Andrew Schrock wrote:
> specific? Gibson has been less than helpful. 

I take this back; Gibson is sending me a service manual free of charge as
we speak. Keeping my fingers crossed.. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From pfperry at melbpc.org.au  Thu Jul  2 17:46:59 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 3 Jul 1998 01:46:59 +1000 (EST)
Subject: ETI-5600 Q's
Message-ID: <1.5.4.16.19961124082225.0dafc180@popa.melbpc.org.au>

well someone here in Melb has bought an ETI that was in the local 
Trading Post 'for sale' mag.. at 7AM!!!!! no wonder I never get anything.

The interesting thing was, it doesn't have the classic patch matrix pin system,
all the boards have been put in a cabinet with leads going to panel sockets
like a 'normal' modular.

Oh, and of course it doesn't work.. ;)

so that's 3 in Melbourne plus one in bits in a box under a bed in StKilda,
and one in Sydney.. anyone else?

paul perry melbourne australia (never seen 7am, never wanted to)




From b.layer at vikingelectronics.com  Thu Jul  2 20:02:02 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 02 Jul 1998 13:02:02 -0500
Subject: tubesource for tubesynth
Message-ID: <3.0.5.32.19980702130202.007a9580@192.168.210.18>

All,

One small sticking point for many who seek to venture into the tube world
is availability of the devices in question. I'm no AES, but I've sure got
new and used multiples of most of the devices called out for in Eric's
designs.

Anyone interested in 'getting tubes' as we say in the industry, may feel
free to contact me on the matter. I'd be happy to trade for whatever... I
also have a small selection of general-purpose tube types (for
experiments), sockets, tube data etc. This stuff is available to
synth-diy-ers only for our purposes, and not generally 'for sale'. My
stocks are not that large.

Good luck!


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From costello at seanet.com  Thu Jul  2 21:01:49 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 02 Jul 1998 12:01:49 -0700
Subject: The Mix 606 Mods - scans of 2nd part of article available?
Message-ID: <359BD91D.836383F1@seanet.com>

Hi all:

Subject says it all.  Sorry if this was answered recently, but I can't
access any archives.  I have the 1st part of the article, but not the
2nd.  I've never seen The Mix (the British version) here in the US, BTW.

Thanks,

Sean Costello



From uzs159 at uni-bonn.de  Thu Jul  2 22:33:42 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Thu, 02 Jul 1998 22:33:42 +0200
Subject: tube synths /VCA
Message-ID: <199807022034.WAA11581@mailhost.bpa.nl>

At 12:04 01.07.1998 -0700, you wrote:

>>I thought pentodes need a high voltage on the screen grid?
>
>Huh? The screen voltage MUST always be LESS than the plate
>voltage! if not, the screen will draw all the plate current,
>possibly (in power tubes) causing damage or (in small tubes
>like we are talking about here) screwing up the tube's operation.

I just thought, since in most poweramp schemes I've seen so far the 
screengrid was directly connected to the supply and the plate via
the output transformer, thus the plate voltage is lower than the 
screengrid.

>The gain of a pentode is controlled by the screen-grid voltage.
>If it is zero, the gain will be zero. If you set it to about
>half the plate voltage, the gain will be maximum--from 100
>to as much as 500 depending on the device.

As I see it the voltage of the screen grid determines the current
thru the tube, right?
But won't then the plate voltage vary with the CV? 

If that is the case would it be better to use either a choke or a 
transfomer instead of the plate-resistor.

>Try it, Rene..........
Yes I'll give it a try.

-Ren?
=(uzs159 at uni-bonn.de)========================
             ,          : 
|") [" |\ | ["          :   This space 
|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From don at till.com  Thu Jul  2 23:43:34 1998
From: don at till.com (Don Tillman)
Date: Thu, 2 Jul 1998 14:43:34 -0700 (PDT)
Subject: 3 throw switches?
In-Reply-To: <359C067B.9F5D203@on-q.com> (message from mark verbos on Thu, 02
	Jul 1998 16:15:23 -0600)
Message-ID: <199807022143.OAA10731@shell9.ba.best.com>

   Date: 	Thu, 02 Jul 1998 16:15:23 -0600
   From: mark verbos <verbos at on-q.com>

   am I nuts here, or is it impossible to find a tripple throw
   switch. Is there a way to wire a 2pole 2 throw switch to be a
   single pole 3 throw switch? Am I nuts? in the buchla quad low
   pass gate, there is a 2pole 3throw switch to select modes. How
   do I do this?!?!?!

You're talking about those little toggle switches, right?  

Get one designated as a "DPDT on-on-on".  That means that it's a DPDT
switch, with a center position, and if we refer to the positions as
left, center, and right, in the center position one pole's wiper is
connected to the left terminal and the other pole's wiper is connected
to the right.  It should be pretty clear how to wire one of these into
a 3PST switch.

This is as opposed to a "DPDT on-off-on" which leaves the poles
unconnected in the center position.

  -- Don




From verbos at on-q.com  Fri Jul  3 00:15:23 1998
From: verbos at on-q.com (mark verbos)
Date: Thu, 02 Jul 1998 16:15:23 -0600
Subject: 3 throw switches?
Message-ID: <359C067B.9F5D203@on-q.com>

hi guys!

am I nuts here, or is it impossible to find a tripple throw
switch. Is there a way to wire a 2pole 2 throw switch to be a
single pole 3 throw switch? Am I nuts? in the buchla quad low
pass gate, there is a 2pole 3throw switch to select modes. How
do I do this?!?!?!
--
mark verbos

"I think the future of analog modulars is to build them
yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
  "No Good Reason" on Thrust, NYC
  "High Metabolism" on A.F.U., Germany





From magnus at analogue.org  Fri Jul  3 00:25:31 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 03 Jul 1998 00:25:31 +0200
Subject: Gene Stopp's e-mail address
In-Reply-To: Your message of "Thu, 25 Jun 1998 09:11:35 -0700 (PDT)"
References: <Pine.3.89.9806250923.A22316-0100000@netcom10>
Message-ID: <199807022225.AAA02669@piraya.electrum.kth.se>

>>>>> "BD" == Brett Duggan <bduggan at netcom.com> writes:

 BD> Hopefully, Gene is already back on this list.  He stated that his new 
 BD> address would be:

 BD> 	squarewave at jps.net

 BD> This is different from the address you typed.

 BD> Brett D

 >> Does anyone have Gene Stopp's current e-mail address?
 >> 
 >> I want to order an ASM-1 pcb from him - and the e-mail address at the ASM-1
 >> site [squarewave at jps.com] doesn't seem to be in service.

Oups!

That is probably due to my fault. I must have remembered incorrectly
when I changed the address on the ASM-1 webpage. Grrr....

It is now fixed.

Dont hit me too hard!

Cheers,
Magnus




From sasami at blaze.net.au  Fri Jul  3 00:33:31 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Fri, 3 Jul 1998 00:33:31 +0200 (MET DST)
Subject: 3 throw switches?
Message-ID: <199807022233.AAA13131@mailhost.bpa.nl>

You may be thinking of a 2 pole, center off switch, if you are thinking of
toggles.

Slide switches are available with three positions.

Otherwise, use a rotary switch. 

ken

>hi guys!
>
>am I nuts here, or is it impossible to find a tripple throw
>switch. Is there a way to wire a 2pole 2 throw switch to be a
>single pole 3 throw switch? Am I nuts? in the buchla quad low
>pass gate, there is a 2pole 3throw switch to select modes. How
>do I do this?!?!?!
>--
>mark verbos
>
>"I think the future of analog modulars is to build them
>yourself."
>
>verbos at on-q.com
>http://www.on-q.com/verbos
>massive magazine... http://www.massivemag.com
>current release...
>  "No Good Reason" on Thrust, NYC
>  "High Metabolism" on A.F.U., Germany
>
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From magnus at analogue.org  Fri Jul  3 01:28:24 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 03 Jul 1998 01:28:24 +0200
Subject: VCO Control Voltages...
In-Reply-To: Your message of "Mon, 29 Jun 1998 09:46:37 -0400"
References: <81A062BC5305D111A9D700805F0659688161B6@maildepo.sc.siemens.com>
Message-ID: <199807022328.BAA03274@piraya.electrum.kth.se>

>>>>> "LC" == List, Christopher <Chris.List at sc.siemens.com> writes:

 LC> 	Hi!
 LC> 	?
 LC> 	Initial work on my home built modular has just started. I've
 LC> tryed the VCO (well... only exp converter) on protoboard and it work
 LC> (finally as I almost threw all away). 

 LC> 	Congrats!

 LC> 	Anyway, my question is about the control voltage
 LC> standards/recommendations. I've decided, my VCO would track from 0 to 10
 LC> V over a ful range (10 octaves). As I saw in ASM VCO design and notes,
 LC> it states that ASM's control voltage ranges fro -15V to 15V. I am
 LC> wondering if ASM is scaled strictly musical or rather freelance... My
 LC> explanation is that only 0 to 10V on ASM are really musical (octaves:)
 LC> and other voltages just extend frequency range. Correct me as I am
 LC> probably wrong. I'd appreciate comments/hints from other users. 

The ASM-1 VCO has a unmodulated (CV sum = 0V) frequency of 909 Hz
which is tuned down to A5 (880 Hz) or a suitable tone nearby.
You can then sweep it from about -14 V to about +8 V to achieve a
88mHz to 102 kHz sweep. So saying that the ASM-1 is only musically
usefull in 0V to 10V is false. The slow frequencies is not really
usefull for audio in themselfs, but as a modulation frequency they
are.

Even if a 19-20 octave sweep isn't directly usefull it is a great
benefit of having a dynamic range to work with. Also, really slow
waveforms becomes blops at a variable frequency rather than a tone
with variable frequency. This is usefull sometimes.

Cheers,
Magnus



From ebarbour at svetlana.com  Fri Jul  3 01:56:05 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 2 Jul 1998 16:56:05 -0700
Subject: tube screens
Message-ID: <01BDA5DA.4DDE26A0.ebarbour@svetlana.com>


>I just thought, since in most poweramp schemes I've seen so far the 
>screengrid was directly connected to the supply and the plate via
>the output transformer, thus the plate voltage is lower than the 
>screengrid.

The difference is only a few volts. And it was cheaper to
connect the output tubes that way--no need to derive a separate
screen supply. And guitar amps are VERY hard on the screen
grids of their output tubes. This is why they have 470 ohm
or 1000 ohm resistors in series with each screen---to limit the
current! Otherwise the screens will get white-hot and melt.

Please. Stop looking at old 6L6 guitar amps, they have very
little to do with small EF86 pentodes in a VCA. 

>As I see it the voltage of the screen grid determines the current
>thru the tube, right?
>But won't then the plate voltage vary with the CV?
>If that is the case would it be better to use either a choke or a 
>transfomer instead of the plate-resistor.

It's always better to use a inductive plate load on a tube.
The issue is always the high cost of a suitable choke or
transformer. High inductance is needed (more than 100
henries for a small preamp tube). You see it done in
exotic high-end audio equipment, rarely in other equipment.
Yes, the plate voltage varies with the screen voltage-
it is slight if the screen voltage is only going 0-5v
of change, as with a typical synthesizer CV.

Another possibility is to use two tubes in balanced
push-pull. Add their outputs with an opamp, thus
canceling the DC common-mode change.

======




From sasami at blaze.net.au  Fri Jul  3 02:15:49 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Fri, 3 Jul 1998 02:15:49 +0200 (MET DST)
Subject: ETI-5600 Q's
Message-ID: <199807030015.CAA15713@mailhost.bpa.nl>

>well someone here in Melb has bought an ETI that was in the local 
>Trading Post 'for sale' mag.. at 7AM!!!!! no wonder I never get anything.

Damn!  and how much was it?

>The interesting thing was, it doesn't have the classic patch matrix pin system,
>all the boards have been put in a cabinet with leads going to panel sockets
>like a 'normal' modular.

Now, the only complete and functional ETI I know of was in this format too.
It was much expanded, with 8 VCO, 5 VCF etc, and was beautifully made. The
rather odd choice of RCA jacks had been chosen as the panel sockets though.
Initially a track missing off the VCF pcbs had prevented them from working,
but that was soon fixed. Alas i have not seen this unit in 10 years, though
I believe the constructor of it still has it. He did as of a year ago. 

In discussions with Melbourne Music, I heard that ETIs do show up there from
time to time, but they NEVER buy them because of the hobbyist factor.
 
>Oh, and of course it doesn't work.. ;)

My one is actually a 3800, though due to me abandoning the original panel
and format, it does not make a lot of difference. I picked up the PCBs, some
of them partially assembled, in the trading post for $80 back in 1990. To
this day, only some of the modules have been completed, though I am still
working on them. Now I've moved I actually have somewhere to work on them!

I have five of the VCAs, as I built four of them back in the '80s. They
suffer from signal bleedthough at the moment. Three are in the process of
being re-panelled. 

The VCF is great. Needs rewiring, as it's a rats nest at the moment.

NOISE worked fine, but needs a new panel.

One VCO has been operational, but needs a panel and wiring. 

MIXERS are used all through the synth. I have a small custom PCB loosely
based on theirs that I use all over the place. 

I have one equalizer, actually built around the eq pcb from the 414 mixer.
This has been modified to the 4600 circuit. (i found the mixer lying beside
the road, put out as hard rubbish. it suffered from the usual hobbyist
problems. Apalling construction, and dead semi's.)

And of course the beloved sequencer, hand wired on proto boards, using
scrap. Initially intended for an unemployed  mate to use with his roland
(which I got for him for $50 DOH!) but since he NEVER powered it up, I
reclaimed it (the seq, not the synth - he won't part with that). Needs
re-boxing, as it is currently mounted in the top of an old Digital computer.

>so that's 3 in Melbourne plus one in bits in a box under a bed in StKilda,
>and one in Sydney.. anyone else?

Care to give details as to which these are?


Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From costello at seanet.com  Fri Jul  3 02:21:22 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 02 Jul 1998 17:21:22 -0700
Subject: Itsy Teenie Small Pots? (for 202 & 606 mods)
Message-ID: <359C2402.F1A6D592@seanet.com>

Hi everybody:

I remember someone writing a while back about really small pots that
were useful for DIY mods.  I'd like to install the Mix mods into my 606,
and adapt some of the Nova Mod ideas for my 202.  Unfortunately, those
beasties have very little room inside.  I really don't want to go the
route of a breakout box.  Does anyone have any good sources for small
pots?  (Not just trimpots, of course - something that you could stick a
knob on.)

>From pictures, the Devilfish (Robin Whittle's 303 mod) uses super small
pots.  Anybody have any idea what he uses?

Thanks,

Sean Costello



From kbalys at ca.newbridge.com  Fri Jul  3 02:56:07 1998
From: kbalys at ca.newbridge.com (Ken Balys)
Date: Thu, 2 Jul 1998 17:56:07 -0700
Subject: Itsy Teenie Small Pots? (for 202 & 606 mods)
Message-ID: <199807030056.RAA28876@salt.ca.newbridge.com>


Well there are: (Digikey source)

Bourns 9mm square panel control pots using conductive plastic.
Available in 1,2,5,10,20,50,100,200,500,1000K
The panel mount series are 3310Y's.
The base is 0.375" per side.
100K is 3319C-1-503-ND but talk to Digikey for specifics.
They are $2.59 each or $22.94 for 10(yikes!)

Panasonic 9mm audio pots are pretty small
The base is 9.7mm by 12.5mm and they are $1.60 each.
Metal bushings. Part is "P3E5???-ND"
The ??? is 502 for 5K, 103 for 10K, 203 for 20K and 503 for 50K.
(sorry no 100K or higher)

If you really want funky pots definately check out the
Bournes stuff. Problem is you are going to be buying 100
if someone like Digikey, Aero Electronics, Electrosonic
don't carry them in stock.

Digikey: 1-800-344-4639 or www.digikey.com

Cheers,
Kenny B.

>Hi everybody:
>
>I remember someone writing a while back about really small pots that
>were useful for DIY mods.  I'd like to install the Mix mods into my 606,
>and adapt some of the Nova Mod ideas for my 202.  Unfortunately, those
>beasties have very little room inside.  I really don't want to go the
>route of a breakout box.  Does anyone have any good sources for small
>pots?  (Not just trimpots, of course - something that you could stick a
>knob on.)
>
>>From pictures, the Devilfish (Robin Whittle's 303 mod) uses super small
>pots.  Anybody have any idea what he uses?
>
>Thanks,
>
>Sean Costello
>



From sasami at blaze.net.au  Fri Jul  3 07:01:56 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Fri, 3 Jul 1998 07:01:56 +0200 (MET DST)
Subject: 3 throw switches?
Message-ID: <199807030501.HAA25642@mailhost.bpa.nl>

Ah. You jog my memory. I've been out of the game too long. Australians can try 

C & K Components Plus Pty Ltd 
  2 Sibthorpe St 
  Braeside VIC 3195 
  Phone (03) 9587 4044 

>Toggle switches ARE still available in:
>Single, Double, Triple and Quadruple Throw
>Single and Double Pole switching systems with
>On, On
>On, Off, On
>And Momentary On, in any combination of the On positions.
>
>C&K is one of the manufacturers that makes them.  (Don't remember who
>supplies them, but you can check Allied; Digi-key; Mouser; Jameco; Radion
>Scrap; etc.
>
>Five
>
>Aural Research Facilities
>"Music you never knew,
>you wanted to hear." :)
>http://www.pangea.ca/~rmiller
>-----Original Message-----
>From: Ken Stone <sasami at blaze.net.au>
>To: mark verbos <verbos at on-q.com>
>Cc: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
>Date: July 2, 1998 5:56 PM
>Subject: Re: 3 throw switches?
>
>
>>You may be thinking of a 2 pole, center off switch, if you are thinking of
>>toggles.
>>
>>Slide switches are available with three positions.
>>
>>Otherwise, use a rotary switch.
>>
>>ken
>>
>>>hi guys!
>>>
>>>am I nuts here, or is it impossible to find a tripple throw
>>>switch. Is there a way to wire a 2pole 2 throw switch to be a
>>>single pole 3 throw switch? Am I nuts? in the buchla quad low
>>>pass gate, there is a 2pole 3throw switch to select modes. How
>>>do I do this?!?!?!
>>>--
>>>mark verbos
>>>
>>>"I think the future of analog modulars is to build them
>>>yourself."
>>>
>>>verbos at on-q.com
>>>http://www.on-q.com/verbos
>>>massive magazine... http://www.massivemag.com
>>>current release...
>>>  "No Good Reason" on Thrust, NYC
>>>  "High Metabolism" on A.F.U., Germany
>>>
>>>
>>>
>>_____________________________________________________________
>>
>>                Ken Stone  sasami at blaze.net.au
>>                   ** Catgirl Paradise **
>>               <http://www.anime.net/~kens/>
>>         ** Australian Miniature Horses and ponies **
>>             <http://www.blaze.net.au/~sasami/>
>>_____________________________________________________________
>>
>>
>>
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From merlin at ion.com.au  Fri Jul  3 08:55:43 1998
From: merlin at ion.com.au (Merlin Zener)
Date: Fri, 03 Jul 1998 16:55:43 +1000
Subject: O-scope question for you old EE's
References: <81A062BC5305D111A9D700805F065968816190@maildepo.sc.siemens.com> <199807020013.CAA09552@piraya.electrum.kth.se>
Message-ID: <359C806F.2B448918@ion.com.au>

Magnus Danielson wrote:
> 
> [...snip]
> If a scope also has a I/V figure
> tracker (easilly built) you have a even more powerfull tool. An I/V
> tracker is a very easy way of comparing a point between a working and
> a failing board, you may see broken inputs due to ESD etc. However,
> few scopes come with this property (the I/V). Few scopes lack XY mode
> thought (I have one which is nothing but XY, it does not even have
> variable input sensitivity).

Good point. I used to have an old cro with one of those,
now I've got one of those new fangled Tektronics digital
ones. It's got a lot of useful functions (voltage & freq
measurements on the screen etc) but that's one thing it
doesn't have. You wouldn't happen to have a circuit to
build the external version, would you?

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 Jul  3 09:38:12 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 3 Jul 1998 09:38:12 +0200 
Subject: AW: Itsy Teenie Small Pots? (for 202 & 606 mods)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827A55D0@nbgm336a.nbgm.siemens.de>

	>If you really want funky pots definately check out the
	>Bournes stuff. Problem is you are going to be buying 100
	>if someone like Digikey, Aero Electronics, Electrosonic
	>don't carry them in stock.

Thought I saw them at Farnell.

JH.




From jocke at netcontrol.fi  Fri Jul  3 10:08:55 1998
From: jocke at netcontrol.fi (Joachim Verghese)
Date: Fri, 3 Jul 1998 11:08:55 +0300 (EET DST)
Subject: Itsy Teenie Small Pots?
In-Reply-To: <359C2402.F1A6D592@seanet.com>
Message-ID: <Pine.LNX.3.95.980703110304.17405B-100000@home.netcontrol.fi>

Alps have a nice selection of small pots.

<http://www.alpscomponents.com/cgi-bin/alpscomponents/catalog.asp?
action=partlist&product=4>

Available in small quantities through Farnell/Newark.

I believe Novation uses Alps 9mm pots for their modules.

-joachim





From urekar.m at EUnet.yu  Fri Jul  3 16:55:21 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Fri, 03 Jul 1998 16:55:21 +0200
Subject: Italian DIY synth
Message-ID: <359CF0D9.409@eunet.yu>

Hi all,

Maybe this is an old one,but I've found this interesting page 
http://diefi.die.unifi.it/~maurri/synth.html
Italian diy synth from S. Maurri,huge,lots of schematics,
paia vcos,ssm vcf and envelopes,moog style vcf,pin matrix,
digital kbd,interesting s&h and ring modulator with LS025 (?)...
Downside:all text in italian
check it out



marjan



From Juergen.Haible at nbgm.siemens.de  Fri Jul  3 17:12:20 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 3 Jul 1998 17:12:20 +0200 
Subject: AW: Serge Waveshaper  was Re: Harmonics question
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827B0152@nbgm336a.nbgm.siemens.de>

>  SC> The second section is...well, no one really seems to know (prove me
> wrong,
>  SC> folks!). It seems to work as follows: When the signal voltage reaches
>  SC> certain thresholds (positive or negative), the signal "wraps around."
> Easy
>  SC> to do in digital (the Nord Modular implements it, and it sounds
> GREAT), but
>  SC> I don't know how to do it in analog. 
> 
I was going thru this thread once more (sorry for the late reply), and then
I
made some experiments with my Interpolating Scanner (schemos and
full description finally on my page at Synthfool), set to waveshaping mode:

When I set every even breakpoint to maximum, and every odd breakpoint to
zero,
I can create a "zigzag" courve, i.e. a triangle waveform in the voltage
domain.
When I modulate this with a normal (time domain) triangle wave of increasing
amplitude, I get a result that *might* be close to the one you described:

The output starts with a triangle wave at fundamental frequency, and at some
point
the peaks are folded back to become ever increasing tringle shaped dents.
At some point, there is a triangle with higher frequency,
and soon after that the peaks of this wave are folded back, too. And so on
to
higher frequencies.
I do not know if this is what this famous Serge module does (can anybody
check this on a real Serge waveshaper?), but if that is the case, it's very
easy to clone, because we'd only need a fraction of the Interpolating
Scanner's
circuitry for that: Omit the VCAs, and omit every other channel completely
(triangle functions not overlapping anymore, but touching the neighbouring
one at its base). Speculating further, I bet Serge has build his module
around
3900's and not saturated pnps. Let me see, one 3900 for 4 triangles, so you
can imagine to what high number of maximum harmonics one can get with a
handful of these chips.

What do you think ?

JH.



From mymoog at ix.netcom.com  Sat Jul  4 00:48:29 1998
From: mymoog at ix.netcom.com (David Lee)
Date: Fri, 3 Jul 1998 17:48:29 -0500
Subject: More MIDI stuff
Message-ID: <199807032244.PAA08693@tardis2.corp.netcom.com>

Also many unit's use a "soft thru". soft thru's can cause delays in the
midi chain, and can sometimes induce a delay that is 50ms or more. An
example of this type of synth is an Emax which allows it's midi "out" to be
used as a "thru" as well (controlled via internal software). If you try to
daisychain from one of these "soft thru" unit you may get an abnormaly high
amount of delay in the signal. Especially if the device is using alot of
the internal CPU for other things (i.e. CC meassages or Pitch wheel)

If this becomes a problem simply buy a MIDI Thru Box which will solve most
MIDI distribution problems.

David Lee

----------
From: media at mail1.nai.net
To: synth-diy at mailhost.bpa.nl
Subject: More MIDI stuff
Date: Wednesday, July 01, 1998 2:17 AM

At 11:47 AM -0400 06/24/98, Silence wrote:
>
>Also, the MIDI spec 1.0 says that the maximum recommended length for
>a MIDI cable is 50'.

Well, 49' if you convert it from metric :)

>After this, the capacitance of the cable rounds off the pulse edges too
>much to be useful.  When chaining together devices, the problem is less
>with losing data, than it is with the time delay becoming very noticable,
>i.e. the first synth sounds 50 milliseconds before the last synth, which
>is a VERY audible differnece.

No, the problem is losing data.  The only delay from a MIDI Thru is from
the optoisolator.  It is about 3uS.  To get a delay of 50mS you would have
to daisy chain over 16,000 MIDI Thrus.  Not even Vince Clarke has that much
gear :)

The limit on the number of MIDI Thru's is from distortion of the signal.
The rise of an optoisolator is only 3uS but it still isn't instantaneous.
So the cumulative effect of a number of optoisolators will shorten the time
of the individual bits eventually causing data to be lost.

PEACE OUT :)
MARK













From magnus at analogue.org  Sat Jul  4 01:59:02 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 04 Jul 1998 01:59:02 +0200
Subject: AW: more frequency tracking.. 
In-Reply-To: Your message of "Thu, 2 Jul 1998 11:23:22 +0200 "
References: <1BF5E20E0C4DD111BBAB00805FE2D582798431@nbgm336a.nbgm.siemens.de>
Message-ID: <199807032359.BAA24150@piraya.electrum.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

Hi all!

 >> The idea of using PLL to have a VCO track along isn't new, the Moog
 HJ> 921
 >> oscillators have a PLL mode.

 HJ> Great surprise for me. Guess I have to look at these schemos again ...

There is this cursuit sitting close to an input and a mode switch
which takes one as the generator waveforms as input (this is from
memory, I am 630 km from my schematics). You will find it in the
middle left on the 921A schematic and it appears on the 921 schematic
as well. I haven't bothered to actually look the chip up but I think
it is a 4-quadrant multiplier or something, thus a classic phase detector.
The 921A clones that I have clearly says PLL and I even recall that an
add says PLL as well. It is a simple curcuit to add to any VCO, so
there is no reason to leave it out.

 >> A first degree is pretty useless for most applications, it has no
 HJ> loop
 >> filter and will make abrupt jumps and has no memory what so
 >> ever. Whenever there is a phase difference it will cause a jump on
 HJ> the
 >> output, not very neat.

 HJ> I have to disagree with "pretty useless", because I worked with
 HJ> the first degree PLL in my diploma thesis (I hope this is the right
 HJ> word), and this PLL made a hell of a good demodulator for
 HJ> FM radio.

I know that PLLs are used as FM demodulators, but I don't strictly recall
their grade. But if you look at what PLLs mostly seems to be used for,
namely frequency and phase locking of a regenerated signal as compared
to a reference signal I think that a first degree is pretty useless.
Saying this will of course not mask out the possibility of them being
very usefull in other fields, such as FM demodulation. I was a bit
wreckless with my language, so sorry...

 HJ> BTW, it can be shown that the schmitt trigger / integrator
 HJ> triangle / square oscillator that is widely used in LFOs will
 HJ> act as 1st order zero crossing PLL when you add one more resistor
 HJ> to the integrator input summing node and use this to feed in your
 HJ> signal. The ratio between the two resistors will then set the
 HJ> hold range of the PLL. I mention this, because I remember seeing
 HJ> a similar circuit in Buchla's famous noise and random module,
 HJ> but I may be wrong here. (Have to look again.)

This is interesting. I will try to meditate a bit over it, but I think
I can see how the schmitt-trigger can become a phase comparator.

The PLL world really consists of many many tricks... in my GPS book
there is things like FLL and DLL as well. Same but diffrent.

 HJ> As for no memory: If there is a pole, there must be some memory,
 HJ> and while there is no capacitor in the (nonexisting) loop filter, there
 HJ> is surely one in the VCO.

Sorry folks, but Juergen and I have started to throw poles at each
other, so keep you toes out!

The pole in the VCO will remember the phase position, not the
advancement of the phase position. What I also mean is that when the
phase detector does detect a difference it will make a direct jump
instead of a smoth transitition from the memory position.

When I say memory I really refer to a memory of the frequency control
voltage. Again I am not being explicit enougth in my lingo, so sorry.

 HJ> So I couldn't resist to comment here. Great post, nevertheless!

Thanks!

Cheers,
Magnus





From magnus at analogue.org  Sat Jul  4 02:51:38 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 04 Jul 1998 02:51:38 +0200
Subject: O-scope question for you old EE's
In-Reply-To: Your message of "Fri, 03 Jul 1998 16:55:43 +1000"
References: <359C806F.2B448918@ion.com.au>
Message-ID: <199807040051.CAA24877@piraya.electrum.kth.se>

>>>>> "MZ" == Merlin Zener <merlin at ion.com.au> writes:

Hi!

 MZ> Magnus Danielson wrote:
 >> 
 >> [...snip]
 >> If a scope also has a I/V figure
 >> tracker (easilly built) you have a even more powerfull tool. An I/V
 >> tracker is a very easy way of comparing a point between a working and
 >> a failing board, you may see broken inputs due to ESD etc. However,
 >> few scopes come with this property (the I/V). Few scopes lack XY mode
 >> thought (I have one which is nothing but XY, it does not even have
 >> variable input sensitivity).

 MZ> Good point. I used to have an old cro with one of those,
 MZ> now I've got one of those new fangled Tektronics digital
 MZ> ones. It's got a lot of useful functions (voltage & freq
 MZ> measurements on the screen etc) but that's one thing it
 MZ> doesn't have. You wouldn't happen to have a circuit to
 MZ> build the external version, would you?

Not yeat. I intend to dream one up, and that should not be very hard.

It is basically just a matter of

1) Generate a waveform
2) Feed the waveform throught a resistor
3) Differentially measure the voltage over the resistor to get the I part
4) Measure the voltage over the applied position to get the V part
5) Connect this up to a component.

The basics is not at all very difficult, to do it properly one should
allow for diffrent voltage and current ranges as well as diffrent
waveform frequency, all in order to measure diffrent things.
A professional tracker can do these things. It is not tricky cursuits
in itself and can all be built pretty well with fairly cheap
components.

Cheers,
Magnus



From cyborg0 at GlobalEyes.net  Sat Jul  4 03:38:08 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Fri, 03 Jul 1998 20:38:08 -0500
Subject: Drumstation V1 probs..
Message-ID: <359D8780.5E4E9DB@globaleyes.net>

If you dont have a drumstation, please delete..

To all who own V1 and other troubled Drumstations..

I have had my drumstation turn-itself off, have noise on the outputs,
erratic functioning, crash, reset etc.. all at the most inappropriate
times while doing shows.

I have found the source of the prob..

for some reason the output of the PS for the drumstation is NOT quite 9v
DC...
So, i replaced it with a PS for a sega genesis that can be bought at any
radio shack. Not only does the Radio Shack PS have about double the
current, but, it has a fairly stiff voltage compared to the
Drumstation...
Now, the only thing you have to do is change the polarity of the Radio
Shack PS to the inner barrel being +.. It comes as inner barrel -. The
wires from the PS need to be switched around..
The PS im using is 9v 1200ma and cost 16 dollars @ radio shack catalog #
273-1612a.

It has cured everything on my drumstation, including:
flickering led readout
crashes
intermittent shutoff
lock-ups
noisy outputs
no controller output
front panel button lockup
volume fluctuation (ie when main on DS was completely turned down, if
there was midi info, it would turn up the mains by itself, then turn off
again)

I have been using it for a few days without problem, and i would suggest
that if you are about to throw your drumstation out the window like i
was, please give this a try. 
rob



From honcho at paia.com  Sat Jul  4 05:54:04 1998
From: honcho at paia.com (honcho at paia.com)
Date: Fri, 3 Jul 98 22:54:04 CDT
Subject: LM566CN VCO,PAIA modules due in August
Message-ID: <9807040354.AA22346@qns1.qns.net>

>improving the performance of the 566 
as a VCO. Perhaps we could prevail on 'el honcho' for some comments?
How 'bout it John?
>>>
This must have been during the '70s, I don't recall :-)

It most likely was nothing more than driving them with a current 
source rather than a voltage. Sometimes you can use pins for 
unintended functions, like using the V- pin as part of a feed-back 
loop and maybe this was it but, seriously, I don't recall. Apologies 
that time is a little right now and I can't go back and research it.

My bud Matt Wilson posted this:

>reports that the
redesigned modules (dual vco, dual vcf, dual just about everything!) 
are
coming along and should be available in August. 
>>>
Man, with this 'net thing you can't get away with nothin - everybody 
knows what you've told everybody else :-) Yes, May has gone to June 
and now August. I'll be leaving the office Tuesday for a working 
vacation that will have me away until Early August. I'll be finishing 
up manuals for the VCF and VCO while away. 

I'm about to bus' wide open holding in a gadget that I want to share 
but not until I've had the opportunity to verify the hardware fully. 
Many months ago JH posted some speculations on using LM13600/13700 
things as expo converters. I saved it, so good that I can't find it 
now, but that's OK because it had burned itself into my head (I really 
wanted the new modules to have an expo different than what's common). 
About six weeks ago I thought I saw a way to do this that would 
eliminate tempcos and produce a circuit with characteristics like the 
3340. The spice simulations of this circuit are beautiful and I have 
some hardware that I've built that initially looks as good as the 
simulation. But I'm having a very difficult time finding the lab time 
to really put it through it's paces.

I will have thoroughly tested this circuit by Tuesday, even if it 
means over-nighters to do it because I can't leave until I'm sure that 
it's doing what I think it's doing.

Since I've said anything at all, I'll let you know what I find out 
even if it leaves me looking a little stupid. But I really think it's 
going to pan out.

-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 Per.Mattsson at mkv.mh.se  Sat Jul  4 13:14:03 1998
From: Per.Mattsson at mkv.mh.se (Per.Mattsson at mkv.mh.se)
Date: Sat, 04 Jul 1998 12:14:03 +0100
Subject: Tubes with "numbers" inside them
Message-ID: <2525036542.4639127@mkv.mh.se>

Hi all!
This is not exactly SDIY but I know of no better source for this than this
list.

I remember from 15-20 years back some lab measuring devices like freq.counters
and some very hightech HIFI equipment like the Revox tuners had  -  I don't
know how to describe them better than - "tubes with glowing numbers inside
them".

If I remember correctly they were mentioned here on SDIY some 6-10 months
back.

I would be very thankful for pictures on those tubes/valves for a interface
design project I'm doing.  I you have pictures or know were I can find them
please mail me privately since this is no SDIY issue.

//Per Mattsson - per.mattsson at mkv.mh.se

-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-
        Sent from The Department of Media and Communication
                      Mid Sweden University
              Information available at Info at mkv.mh.se
-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-




From blacet at metro.net  Sat Jul  4 13:19:35 1998
From: blacet at metro.net (John Blacet)
Date: Sat, 04 Jul 1998 11:19:35 +0000
Subject: Tubes with "numbers" inside them
References: <199807041638.JAA07502@shell9.ba.best.com>
Message-ID: <359E0FC7.13E1@metro.net>

The modern equivalent is the VF display (vacuum fluorescent) with their
bright geenish-blue color; actually one of the most readable displays
around. Needs some fairly high voltage--supplied by inverter typically.
-- 

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



From mglnsky at magicnet.net  Sat Jul  4 17:32:18 1998
From: mglnsky at magicnet.net (Mark Glinsky)
Date: Sat, 4 Jul 1998 11:32:18 -0400 (EDT)
Subject: Tubes with "numbers" inside them
Message-ID: <199807041532.LAA24393@magicnet.magicnet.net>

>I remember from 15-20 years back some lab measuring devices like freq.counters
>and some very hightech HIFI equipment like the Revox tuners had  -  I don't
>know how to describe them better than - "tubes with glowing numbers inside
>them".
>If I remember correctly they were mentioned here on SDIY some 6-10 months
>back.

Those are the  old Nixie tubes - I have  a Hewlett-Packard
frequency counter that uses them.
Still have some Nixies sitting around as well, was
going to make a  giant clock out  of  them 20-some
years ago!


_______________________________________________________
 Mark Glinsky -   Orlando, Florida
 Email:                 mglnsky at magicnet.net
 Manual Manor:   http://www.magicnet.net/~mglnsky/msg4.html
 "Be seeing you...."  [ No. 6  -  The Prisoner ]
 "Don't Panic!"   [ HitchHiker's Guide ]
-------------------------------------------------------




From cyborg0 at GlobalEyes.net  Sat Jul  4 17:43:45 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 04 Jul 1998 10:43:45 -0500
Subject: Tubes with "numbers" inside them/nixie tubes
References: <2525036542.4639127@mkv.mh.se>
Message-ID: <359E4DB1.3AF47602@globaleyes.net>

They are called Nixie Tubes.. they look very retro, and, yes, some of
our freq counters/timers at work still use them.. They are really cool,
but, i hate to tell you that they are very hard to find these days and
also very expensive, at least when compared to 7 segment leds.
They can be driven by BCD to Nixie drivers which are 74xxx series
chips..pretty easy to use, but expensive, although nothing beats that
red glowing dancing number look!
rob

Per.Mattsson at mkv.mh.se wrote:
> 
> Hi all!
> This is not exactly SDIY but I know of no better source for this than this
> list.
> 
> I remember from 15-20 years back some lab measuring devices like freq.counters
> and some very hightech HIFI equipment like the Revox tuners had  -  I don't
> know how to describe them better than - "tubes with glowing numbers inside
> them".
> 
> If I remember correctly they were mentioned here on SDIY some 6-10 months
> back.
> 
> I would be very thankful for pictures on those tubes/valves for a interface
> design project I'm doing.  I you have pictures or know were I can find them
> please mail me privately since this is no SDIY issue.
> 
> //Per Mattsson - per.mattsson at mkv.mh.se
> 
> -?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-
>         Sent from The Department of Media and Communication
>                       Mid Sweden University
>               Information available at Info at mkv.mh.se
> -?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-?-



From don at till.com  Sat Jul  4 18:38:35 1998
From: don at till.com (Don Tillman)
Date: Sat, 4 Jul 1998 09:38:35 -0700 (PDT)
Subject: Tubes with "numbers" inside them
In-Reply-To: <2525036542.4639127@mkv.mh.se> (Per.Mattsson@mkv.mh.se)
Message-ID: <199807041638.JAA07502@shell9.ba.best.com>

   From: Per.Mattsson at mkv.mh.se
   Date: Sat, 04 Jul 1998 12:14:03 +0100

   I remember from 15-20 years back some lab measuring devices like
   freq.counters and some very hightech HIFI equipment like the Revox
   tuners had - I don't know how to describe them better than - "tubes
   with glowing numbers inside them".

As others have said, "Nixie Tubes".  I miss them terribly.

I've always thought that they would be wonderfully cool displays for
modern electronic music equipment!  (Arguably a hell of lot more
readable than that LCD disaster on my NAD CD player.)  At the very
least Nixies would be the appropriate display for a midi controlled
tube guitar preamp.  Or when one of Eric Barbour's creations gets
patch storage.

A web search finds the following:
http://www.wps.com/archives/decimal-tubes/index.html
http://www.public.usit.net/rfurr/images/nixie3.gif
http://www.geocities.com/SiliconValley/Park/7227/classifid.html
http://www.cs.orst.edu/~rpandey/images/nixie.gif

Oh wow, I remember these Wang calculators set up at the Boston Science
Museum around 1970!
http://www.dotpoint.com/xnumber/wang.htm

There's also a view of a Nixie tube display on a Smashing Pumkins
video; I think it's called "Rocket".

  -- Don



From cyborg0 at GlobalEyes.net  Sat Jul  4 23:30:57 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 04 Jul 1998 16:30:57 -0500
Subject: Tubes with "numbers" inside them
References: <199807041638.JAA07502@shell9.ba.best.com> <359E0FC7.13E1@metro.net>
Message-ID: <359E9F11.6B422FB@globaleyes.net>

Yuch! how dare you compare big, nice,
brightly-lit-with-a-3d-counting-effect nixie tubes with those blocky VF
displays!! ;) 
honestly, nixie tubes have to be THE easiest things to read cuz if youre
off center you can still read them rather well..really cool..

John Blacet wrote:
> 
> The modern equivalent is the VF display (vacuum fluorescent) with their
> bright geenish-blue color; actually one of the most readable displays
> around. Needs some fairly high voltage--supplied by inverter typically.
> --
> 
> Regards.
> -------------------------
> John Blacet
> Blacet Research Music Electronics
> -------------------------
> blacet at metro.net
> http://metro.net/blacet/music.html



From mase at post5.tele.dk  Sun Jul  5 00:06:45 1998
From: mase at post5.tele.dk (Martin Selway)
Date: Sun, 5 Jul 1998 00:06:45 +0200
Subject: [Digital_Hell] Drumstation V1 probs..
Message-ID: <007101bda798$537fe480$c0a2f9c3@selway1>

There is a Novation help forum on their homepage:    http://www.nova-uk.com/
There are solutions for the mentioned problems and other bugs.

regards,

MARTIN
mase at post5.tele.dk
http://home5.inet.tele.dk/mase

-----Original Message-----
From: cyborg0 at globaleyes.net <cyborg0 at globaleyes.net>
To: analogue at hyperreal.org <analogue at hyperreal.org>;
digitalhell at resrocket.com <digitalhell at resrocket.com>; electronica2
<electronica-request at noether.ex.ac.uk>; electronica
<electronica-request at andrew.cmu.edu>; synth-diy <synth-diy at mailhost.bpa.nl>
Date: l?rdag, juli 04, 1998 03:45
Subject: [Digital_Hell] Drumstation V1 probs..


>If you dont have a drumstation, please delete..
>
>To all who own V1 and other troubled Drumstations..
>
>I have had my drumstation turn-itself off, have noise on the outputs,
>erratic functioning, crash, reset etc.. all at the most inappropriate
>times while doing shows.
>
>I have found the source of the prob..
>
>for some reason the output of the PS for the drumstation is NOT quite 9v
>DC...
>So, i replaced it with a PS for a sega genesis that can be bought at any
>radio shack. Not only does the Radio Shack PS have about double the
>current, but, it has a fairly stiff voltage compared to the
>Drumstation...
>Now, the only thing you have to do is change the polarity of the Radio
>Shack PS to the inner barrel being +.. It comes as inner barrel -. The
>wires from the PS need to be switched around..
>The PS im using is 9v 1200ma and cost 16 dollars @ radio shack catalog #
>273-1612a.
>
>It has cured everything on my drumstation, including:
>flickering led readout
>crashes
>intermittent shutoff
>lock-ups
>noisy outputs
>no controller output
>front panel button lockup
>volume fluctuation (ie when main on DS was completely turned down, if
>there was midi info, it would turn up the mains by itself, then turn off
>again)
>
>I have been using it for a few days without problem, and i would suggest
>that if you are about to throw your drumstation out the window like i
>was, please give this a try.
>rob




From sasami at blaze.net.au  Sun Jul  5 00:54:38 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Sun, 5 Jul 1998 08:54:38 +1000 (EST)
Subject: Tubes with "numbers" inside them
Message-ID: <199807042254.IAA01103@blaze.net.au>

Actually, closer to nixie tubes than fluoro displaysis the neon 7 segment
display. I have one of these curios in my collection, as well as a single
relatively large nixie tube. I recall coming across a whole bank of these in
subminiature format some time back, but where and when escapes me.
Unfortunately, it does not appear that they were mine. I can't find them
anywhere.

Ken 

>The modern equivalent is the VF display (vacuum fluorescent) with their
>bright geenish-blue color; actually one of the most readable displays
>around. Needs some fairly high voltage--supplied by inverter typically.
>-- 
>
>Regards.
>-------------------------
>John Blacet
>Blacet Research Music Electronics
>-------------------------
>blacet at metro.net
>http://metro.net/blacet/music.html
>
>
_______________________________________________________________________
Ken Stone   sasami at blaze.net.au  
Catgirl Paradise <http://www.anime.net/~kens/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




From svetengr at earthlink.net  Sun Jul  5 07:47:43 1998
From: svetengr at earthlink.net (Eric at Svetlana Electron Devices)
Date: Sat, 04 Jul 1998 22:47:43 -0700
Subject: Tubes with "numbers" inside them
Message-ID: <199807050547.WAA18928@cuckoo.prod.itd.earthlink.net>


>   I remember from 15-20 years back some lab measuring devices like
>   freq.counters and some very hightech HIFI equipment like the Revox
>   tuners had - I don't know how to describe them better than - "tubes
>   with glowing numbers inside them".
>
>As others have said, "Nixie Tubes".  I miss them terribly.

I'm preparing to write an article about the early history of display tubes.
Have amassed a large collection of Nixies, Pixies, Dekatrons, Numitrons
and counter tubes. Plus data and application info.
If you need more information, just ask.




From shudder at optusnet.com.au  Sun Jul  5 09:30:54 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Sun, 5 Jul 1998 17:30:54 +1000
Subject: [sdiy] Doepfer Schematics
Message-ID: <007001bda7e6$da665c60$4f268ec6@dialup.mpx.com.au>

Just saw these, REVENGE!!
http://www.doepfer.de/a110_tec.htm
http://www.doepfer.de/ms404_sm.htm
Sean




From ROBODON at aol.com  Sun Jul  5 13:24:19 1998
From: ROBODON at aol.com (ROBODON at aol.com)
Date: Sun, 5 Jul 1998 07:24:19 EDT
Subject: front panels
Message-ID: <4c171fac.359f6264@aol.com>

Was reading the latest front panels by trophy shop and remembered that I have
a friend right here in Austin Texas that does laser engraving. I've seen
examples of his work where he's etched anodized aluminum. The sample I saw was
about a ten inch circle about an inch thick (some sort of lamp base or
something). It was anodized black and the letters came out white. If I hadn't
watched the laser burn it i would have sworn it was white silk screen.  He
works from CAD files or usually COREL Draw.  If anyone wants to try him you
can get to him through me: ROBODON at aol.com or directly at ohlaser at flash.net
(Oak Hill Laser Engraving)
As in all these processes the more the merrier and guessing from the size of
the machine he could probably stack about 20 single width panels at a time in
it.

Don Colbath

Remember...Never fry Chicken when you're naked!



From tomg at vivid.net  Sun Jul  5 13:43:56 1998
From: tomg at vivid.net (tomg)
Date: Sun, 05 Jul 1998 06:43:56 -0500
Subject: Maxx VCO-3374A Addition
Message-ID: <yam7490.2846.118910136@mail.vivid.net>

I added the VCO-3374A module to my Maxx pages.

I have started work on the Mini1cv. Again something I built for the m1cv ended
up in the Maxx. But work continues and the m1cv will be here soon. 
All of the drawings and layouts are done, I just have to put it together.

This dual VCO is build arround a Curtis CEM-3374. Have I mentioned this is a
great chip!! It contains two high presision VCOs. I configured the 3374
normally . Temp comp pin 10 of the 3374 is not used. I thought about it and
maybe a freq/volt converter like the 9400 could be used to provide CV for temp
comp but not this time, stability is still very good as it is. If you want to
do temp comp use a tempco just as you would for any standard design. The
VCO-3374 will run on +-15V/-5V as well as +-12V/-5V. The VCOs are independant
and can be run in LFO mode. Features ramp/pulse/tri waves, sync and fm.

synthtech.com has the CEM3374 in stock at $15 each.


http://www.tomg.vivid.net/maxx/page_028.html

-Tom




From Per.Mattsson at mkv.mh.se  Sun Jul  5 14:41:46 1998
From: Per.Mattsson at mkv.mh.se (Per.Mattsson at mkv.mh.se)
Date: Sun, 05 Jul 1998 13:41:46 +0100
Subject: Tubes with "numbers" inside them
In-Reply-To: <359f407e.145955406@mail.lan>
References: <359f407e.145955406@mail.lan> <2525036542.4639127@mkv.mh.se>
Message-ID: <2525036542.10118339@mkv.mh.se>

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From tomg at vivid.net  Sun Jul  5 21:11:58 1998
From: tomg at vivid.net (tomg)
Date: Sun, 05 Jul 1998 14:11:58 -0500
Subject: LM566CN VCO
In-Reply-To: <9807040354.AA22346@qns1.qns.net>
Message-ID: <yam7490.2924.118826640@mail.vivid.net>


John used a LM566 VCO in his 5700 Drum Synth. He extended it's range but did
not use a exp conv. As it is it's not useful as a 1v/oct VCO but it could be
if someone adds a exp conv.

566 VCO

Pin 1    -V
Pin 2    NC
Pin 3    Sq Out
Pin 4    Tri Out
Pin 5    3.3M to +V and 1M to gnd
Pin 6    CV in
Pin 7    .05 to -V
Pin 8    +V

-Tom







From tomg at vivid.net  Mon Jul  6 03:21:57 1998
From: tomg at vivid.net (tomg)
Date: Sun, 05 Jul 1998 20:21:57 -0500
Subject: LM566CN VCO
In-Reply-To: <yam7490.2924.118826640@mail.vivid.net>
Message-ID: <yam7490.2876.118821776@mail.vivid.net>

On 05-Jul-98, tomg wrote:

>John used a LM566 VCO in his 5700 Drum Synth. He extended it's range but did
>not use a exp conv. As it is it's not useful as a 1v/oct VCO but it could be
>if someone adds a exp conv.

>566 VCO

>Pin 1    -V
>Pin 2    NC
>Pin 3    Sq Out
>Pin 4    Tri Out
>Pin 5    3.3M to +V and 1M to gnd
>Pin 6    CV in
>Pin 7    .05 to -V
>Pin 8    +V

>-Tom


Sorry +-V = +-9V

-Tom






From Juergen.Haible at nbgm.siemens.de  Mon Jul  6 10:58:27 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 6 Jul 1998 10:58:27 +0200 
Subject: AW: AW: more frequency tracking.. 
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827B8AE1@nbgm336a.nbgm.siemens.de>


	> it is a 4-quadrant multiplier or something, thus a classic phase
detector.

Ahh, I remember this one. Interesting !

>  >HJ> BTW, it can be shown that the schmitt trigger / integrator
	> HJ> triangle / square oscillator that is widely used in LFOs will
	> HJ> act as 1st order zero crossing PLL when you add one more
resistor
>  >HJ> to the integrator input summing node and use this to feed in your
>  >HJ> signal. The ratio between the two resistors will then set the
>  >HJ> hold range of the PLL. I mention this, because I remember seeing
	> HJ> a similar circuit in Buchla's famous noise and random module,
>  >HJ> but I may be wrong here. (Have to look again.)
	>
	>This is interesting. I will try to meditate a bit over it, but I
think
	>I can see how the schmitt-trigger can become a phase comparator.

Think of an XOR gate as phase dedector for a start. The phase
difference output is a PWM-ed pulse CV (as there is no loop 
filter) instead of an analogue voltage.
To make a PWM-controlled VCO from the basic oscillator, you need
to change direction of the charge / discharge operation of the
capacitor, depending on the current state of the oscillator.
So the whole PLL uses (theoretically) one XOR for the PD,
and another XOR (in series) for the VCO function, with the second
inputs of both XOR gates connected to the VCO output.
These two XOR fuctions cancel, of course, and the result is that
it reduces to a simple resistor. If you draw it to a piece of
paper, it's quite obvious.
(My prof liked the mathematical proof better, but the lazy guy
that I am, I prefer graphical deduction.)

	JH.




From b.layer at vikingelectronics.com  Mon Jul  6 16:42:36 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 06 Jul 1998 09:42:36 -0500
Subject: EML-200 parts
Message-ID: <3.0.5.32.19980706094236.007bae20@192.168.210.18>

All,

Can anyone supply me with a front cover for my EML-200 synth? I know this a
very rare part, but I'd like to have it. Trades available...


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From b.layer at vikingelectronics.com  Mon Jul  6 19:47:38 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 06 Jul 1998 12:47:38 -0500
Subject: tubesource for tubesynths
Message-ID: <3.0.5.32.19980706124738.007bc1a0@192.168.210.18>

All,

One small sticking point for many who seek to venture into the tube world
is availability of the devices in question. I'm no AES, but I've sure got
new and used multiples of most of the devices called out for in Eric's
designs.

Anyone interested in 'getting tubes' as we say in the industry, may feel
free to contact me on the matter. I'd be happy to trade for whatever... I
also have a small selection of general-purpose tube types (for
experiments), sockets, tube data etc. This stuff is available to
synth-diy-ers only for our purposes, and not generally 'for sale'. My
stocks are not that large.

Good luck!


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From uzs159 at uni-bonn.de  Mon Jul  6 23:51:42 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Mon, 06 Jul 1998 23:51:42 +0200
Subject: LM566 VCO is alive
Message-ID: <199807062152.XAA03208@mailhost.bpa.nl>

Hi SynthFolks,

Today I completed the construction of an 566 VCO with expo current control.
I did not have the time to do much tests, but first experiments show that
the circuit I build is suitable for the audio range. With minimum frequency
setting
I can obtain about 2Hz and the upper limit is beyond the hearing range
(>16-20k).
This would be more than the expected 1:100 sweep range.
I'll post a more detailed description soon, and the schematic will appear on my
website.

Bye
-Ren?

=(uzs159 at uni-bonn.de)========================
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|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From magnus at analogue.org  Tue Jul  7 00:08:27 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Tue, 07 Jul 1998 00:08:27 +0200
Subject: AW: AW: more frequency tracking.. 
In-Reply-To: Your message of "Mon, 6 Jul 1998 10:58:27 +0200 "
References: <1BF5E20E0C4DD111BBAB00805FE2D5827B8AE1@nbgm336a.nbgm.siemens.de>
Message-ID: <199807062208.AAA00766@piraya.electrum.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 >> it is a 4-quadrant multiplier or something, thus a classic phase
 HJ> detector.

 HJ> Ahh, I remember this one. Interesting !

Yeah.

 >> This is interesting. I will try to meditate a bit over it, but I think
 >> I can see how the schmitt-trigger can become a phase comparator.

 HJ> Think of an XOR gate as phase dedector for a start. The phase
 HJ> difference output is a PWM-ed pulse CV (as there is no loop 
 HJ> filter) instead of an analogue voltage.
 HJ> To make a PWM-controlled VCO from the basic oscillator, you need
 HJ> to change direction of the charge / discharge operation of the
 HJ> capacitor, depending on the current state of the oscillator.
 HJ> So the whole PLL uses (theoretically) one XOR for the PD,
 HJ> and another XOR (in series) for the VCO function, with the second
 HJ> inputs of both XOR gates connected to the VCO output.
 HJ> These two XOR fuctions cancel, of course, and the result is that
 HJ> it reduces to a simple resistor. If you draw it to a piece of
 HJ> paper, it's quite obvious.

Hmm... interesting. However, I think that this kind of PLL does
however make very abrupt jumps in their phase and thus frequency each
time that they compensate. Such jumps may not allways be advantagous.
There is even cases where such jumps is nothing but catastrophic.
I can't help it, but for some reason I like smooth curves :)

But as allways, look at each and every case and find what are the
limits for this applications and then find the solution for that
application.

 HJ> (My prof liked the mathematical proof better, but the lazy guy
 HJ> that I am, I prefer graphical deduction.)

But then, I have a friends doctorate paper at home, and it is such a
mathematical proof of the whole thing that most people in the
buissness does not understand it. Let's just say that his family stood
no chance of understanding basically anything between Wellcome and
Thanks for comming on his defence. I know that I didn't get much anyway.

Cheers,
Magnus



From RevTor at aol.com  Tue Jul  7 00:24:43 1998
From: RevTor at aol.com (RevTor at aol.com)
Date: Mon, 6 Jul 1998 18:24:43 EDT
Subject: Piezo thought..
Message-ID: <66ca0f23.35a14eaf@aol.com>

I am not sure about how piezos respond to pressure, but here's an idea I had
that would be cool if it could work.  One could be wired as a straight
trigger, and the other as a cv source for a VCA.  If they give more voltage
with more pressure..??     Now you have velocity sensitive finger drums!!!
???  ....
And one more thing,  what kind of de-fluxer is anyone using?  mine isn't good
for some plastics and I don't want to harm my caps or trimmers, plus it leaves
a white residue if not wiped off when wet.  Should I just deal with these
little problems or what? Do most of you just de-flux the bottoms of your
boards?  
Thanks.
~Steve   



From Juergen.Haible at nbgm.siemens.de  Tue Jul  7 14:19:33 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 7 Jul 1998 14:19:33 +0200 
Subject: OB-8 Poly Modulation Mod schemos online
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827CD702@nbgm336a.nbgm.siemens.de>

The missing schematics diagram is online now (Thanks, Kevin !).
You can find it at <http://www.synthfool.com/diy/hjob8pmm.gif>.
The description is (still) at <http://www.synthfool.com/diy/hj_pmob8.html>.

As you can see, not many components are needed. Just a little patience
to do the same thing 8 times.

JH.



From sebsi23 at hooked.net  Tue Jul  7 19:06:46 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Tue, 07 Jul 1998 10:06:46 -0700
Subject: inverting a voltage?
Message-ID: <35A255A5.A96C702D@hooked.net>

i need to invert the voltage at the trig out of a korg sq10 so i can use

it with "normal" gear.

advice requested for this simple mod. i can't find it anywhere.




From uzs159 at uni-bonn.de  Wed Jul  8 00:16:30 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 08 Jul 1998 00:16:30 +0200
Subject: 566 Schematic online
Message-ID: <199807072217.AAA15945@mailhost.bpa.nl>

... at http://www.uni-bonn.de/~uzs159/vco_566.html

bye

=(uzs159 at uni-bonn.de)========================
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|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From media at mail1.nai.net  Wed Jul  8 00:42:00 1998
From: media at mail1.nai.net (media at mail1.nai.net)
Date: Tue, 7 Jul 1998 18:42:00 -0400 (EDT)
Subject: inverting a voltage?
In-Reply-To: <35A255A5.A96C702D@hooked.net>
Message-ID: <v03130304b1c81bc65761@[209.150.36.19]>

At 10:06 AM -0700 07/07/98, matt wilson wrote:
>i need to invert the voltage at the trig out of a korg sq10 so i can use
>
>it with "normal" gear.
>
>advice requested for this simple mod. i can't find it anywhere.

I found this in my files:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There was someone asking about a circuit to generate voltage triggers from
an S-trigger out.  Well, here's the ASCII version of the circuit that
appeared in the March 1982 Keyboard  (Kraftwerk on the cover!)  Note that
this is for a 0/9v v-trigger.  If you need 15 volts, I'm sure it's a simple
change.


This will produce a voltage
trigger in response to an
s-trigger out.  The trigger                 Off
voltage will be 0 or 9 volts.            ___o       ___________
Close the switch to use, open           /          | 9-volt    |
it to save the battery life.     |-----o    o---- +| battery   |-- ground
                 ________________|          On     |___________|
                 \               \
                 /               /
             10k \           10k \
                 /               /
                 |               |----------------------- to tip of jack
                 |               |                        sleeve to ground
                 |    100k       /
      ___________|___/\/\/\___|/
      |                       |\   2N3904 or equivalent
 1   -|-  S-trigger              \
    _____     in                 |
 2    |                          |
      |                         ---
      |                  ground  -
     ---  ground
      -






From chordman at flash.net  Wed Jul  8 00:54:21 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Tue, 07 Jul 1998 22:54:21 GMT
Subject: inverting a voltage?
In-Reply-To: <35A255A5.A96C702D@hooked.net>
References: <35A255A5.A96C702D@hooked.net>
Message-ID: <35a9a6a1.76366572@mail.lan>

On Tue, 07 Jul 1998 10:06:46 -0700, matt wilson <sebsi23 at hooked.net>
wrote:

>i need to invert the voltage at the trig out of a korg sq10 so i can use
>
>it with "normal" gear.
>
>advice requested for this simple mod. i can't find it anywhere.

Is this an inversion in the logic gate sense or true analog inversion?

Also, what levels are present?  What levels are required?  I'm not
sure *any* gear is normal per se.  Some methods may just be more
common than others.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From bmwoenig at pop.merlin.net.au  Wed Jul  8 01:36:35 1998
From: bmwoenig at pop.merlin.net.au (Benjamin Woenig 9705146x)
Date: Tue, 7 Jul 1998 23:36:35 +0000
Subject: ETI-5600 Q's
In-Reply-To: <1.5.4.16.19961123010934.2f678cd8@popa.melbpc.org.au>
Message-ID: <199807080113.KAA03748@arthur.merlin.net.au>


Sorry for such a late reply, but i've mentioned the ETI series of 
synths on the list before with the same response - don't bother with 
poor design and over complex circuitry. As a result of this ive 
decided that Tomg's design is the best so far. 

But one problem, no PCB's. So to get around this i'm thinking about 
getting some made up professionally, but the place i wanna use only 
make a minimum of 10, at minimum $20 each.  By the time ive got EG, 
VCFs, VCAs, VCOs etc, the cost is going to be over $1000. Would 
people be interested in buying these boards if i got them made up? If 
people don't then i guess i'm going to have a mother of a modular! 10 
oscillators boards with 2 per PCB = 20 oscilators!

L8r...

<bUd>
> Jim, I can't recommend the ETI ckts..
> they just 'look wrong' too.. not many success stories in this field.
> Really, you'd be much better using more recent ckts from the net eg from
> Tomg. And, there are plenty of mixer ckts out there.
> I have a (non-working) ETI sequencer, and have seen ones that do work.
> It's just a standard ring thing with leds and pots, nothing flash.
> The fact that the boards are available, while a minor miracle, is not
> justification enough in my opinion.





From bmwoenig at pop.merlin.net.au  Wed Jul  8 01:36:35 1998
From: bmwoenig at pop.merlin.net.au (Benjamin Woenig 9705146x)
Date: Tue, 7 Jul 1998 23:36:35 +0000
Subject: ETI-5600 Q's
In-Reply-To: <1.5.4.16.19961124082225.0dafc180@popa.melbpc.org.au>
Message-ID: <199807080113.KAA03745@arthur.merlin.net.au>


> The interesting thing was, it doesn't have the classic patch matrix pin system,
> all the boards have been put in a cabinet with leads going to panel sockets
> like a 'normal' modular.
> 
> Oh, and of course it doesn't work.. ;)
> 
> so that's 3 in Melbourne plus one in bits in a box under a bed in StKilda,
> and one in Sydney.. anyone else?


I know theres at least one in Adelaide somewhere.  A local radio DJ 
tried unsuccessfully building one about 20 years ago :) He then sold 
it in pieces to some1 else...

<bUd>
L8r...,

  <ThE BuDWeiSeR / FtS>
           aKa  
       <Jah  amiN> 



From rarrick at ix.netcom.com  Wed Jul  8 02:38:32 1998
From: rarrick at ix.netcom.com (Roger Arrick)
Date: Tue, 07 Jul 1998 19:38:32 -0500
Subject: SynthDIY: Prophet 2000 for sale
References: <v03130304b1c81bc65761@[209.150.36.19]>
Message-ID: <35A2BF88.6E27830D@ix.netcom.com>

Synth-DIY folks:

Sequential Circuits Prophet-2000 Sampling Keyboard for sale.
Once owned by pseudo synth god Paul Schreiber.
A couple of dozen disks.  Some unreadable.
Full documentation and schematics
Has version 4 software upgrade.
See picture at http://www.robotics.com/p2000.jpg

Contact mailto:roger at robotics.com for info.

Price: $300 plus shipping
Located in the Dallas/Fort Worth Area.

Roger.


    /----------------------------/---------------------------/
   /      Roger Arrick          /     Arrick Robotics       /
  / mailto:roger at robotics.com  /       P.O. Box 1574       /
 /  http://www.robotics.com   /   Hurst, Texas 76053 USA  /
/----------------------------/---------------------------/



From gur-m at internet-zahav.net  Wed Jul  8 05:17:05 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Wed, 08 Jul 1998 05:17:05
Subject: ASM1 Tempco need
Message-ID: <3.0.2.16.19980708051705.4def45b4@mail.internet-zahav.net>

helo every body.
i'm looking for Tempco for my ASM1 VCF,VCO and
want to know if any body that build his asm1 with this with
good results
can reply me with the manufecture name and catalog no' ?
i chack the DIY  archive but found nothing that realy helps.

thanx
Gur Milstein




From debus at cww.de  Wed Jul  8 07:59:34 1998
From: debus at cww.de (Ingo Debus)
Date: Wed, 08 Jul 1998 07:59:34 +0200
Subject: LM566 VCO is alive
References: <199807062152.XAA03208@mailhost.bpa.nl>
Message-ID: <35A30AC6.6050@cww.de>

Rene Schmitz wrote:
> Today I completed the construction of an 566 VCO with expo current control.

Did you think about the possibility of using a XR2206 instead of a 556?
The 2206 too has a current input for frequency control.

Many years ago I planned a VCO with the 2206 and the expo converter from
the Formant. But I dropped this as the Curtis chips appeared.

Ingo




From pfperry at melbpc.org.au  Wed Jul  8 09:53:10 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 8 Jul 1998 17:53:10 +1000 (EST)
Subject: ETI-5600 Q's & PCB costs
Message-ID: <1.5.4.16.19961130002843.39578e3c@popa.melbpc.org.au>

At 11:36 PM 7/07/98 +0000, you wrote:
>
, but the place i wanna use only 
>make a minimum of 10, at minimum $20 each. 
....these are ludicrous prices for single sided boards...
in Australia, use Printed Electronics, in Melbourne 03.9545.3722
Tell Mike Lynch I sent you.

paul perry, Frostwave P/L Melbourne Australia

Also, prob work out cheaper combining sections onto 1 or 2 boards..





From Charles_Moseley%MCKINSEY-EXTERNAL at MCKINSEY.COM  Wed Jul  8 12:28:58 1998
From: Charles_Moseley%MCKINSEY-EXTERNAL at MCKINSEY.COM (Charles Moseley)
Date: Wed, 8 Jul 1998 11:28:58 +0100
Subject: EDP wasp conversion
Message-ID: <8025663B.00393016.00@NA-GATEWAYS02.NOTES.MCKINSEY.COM>





Charles Moseley at MCKINSEY-EXTERNAL
07/08/98 06:28 AM


To:   synth-diy at mailhost.bpa.nl@internet
cc:
Subject:  EDP wasp conversion


I am looking for a midi-wasp converter so that I can run the wasp from
Cubase but I do not want to spend ?110 on a converter (This is more than I
paid for the Wasp). I know that the Wasp uses a digital interface and so
may be a bit of a challenge for an electonics novice like me, but is there
a diy conversion method I can use, or a  cheaper solution?

Thanks in advance




Charlie





From tpaddock at seanet.com  Wed Jul  8 16:31:08 1998
From: tpaddock at seanet.com (Toby Paddock)
Date: Wed, 8 Jul 1998 07:31:08 -0700
Subject: 3 throw switches?
Message-ID: <01BDAA42.F3421680@d30.dialup.seanet.com>

I've got some like Don describes.  C&K  model 7211.  
Mine have a locking lever (pull to unlock), but I don't think that's part of the 7211 number.
It wasn't real clear to me how to wire it SP3T.

Label the terminals:

3
2 - wiper
1

and

6
5 - wiper
4

jumper 3 to 5

IN is 2

OUTs are 1, 4, and 6

Also, the thing LOOKS just like a DPDT on-off-on switch and it gets ugly if you mix them up.

Hoping this finds you,
Toby Paddock
- -- -  - -- -  - -- -  - -- -  - -- -
http://www.seanet.com/~tpaddock
Pronteon Approved, 
clean with a soft damp cloth if required

-------------------------------------------------------------------------
----------
From: 	Don Tillman[SMTP:don at till.com]
Reply To: 	don at till.com
Sent: 	Thursday, July 02, 1998 7:43 AM
To: 	verbos at on-q.com
Cc: 	synth-diy at mailhost.bpa.nl
Subject: 	Re: 3 throw switches?

   Date: 	Thu, 02 Jul 1998 16:15:23 -0600
   From: mark verbos <verbos at on-q.com>

   am I nuts here, or is it impossible to find a tripple throw
   switch. Is there a way to wire a 2pole 2 throw switch to be a
   single pole 3 throw switch? Am I nuts? in the buchla quad low
   pass gate, there is a 2pole 3throw switch to select modes. How
   do I do this?!?!?!

You're talking about those little toggle switches, right?  

Get one designated as a "DPDT on-on-on".  That means that it's a DPDT
switch, with a center position, and if we refer to the positions as
left, center, and right, in the center position one pole's wiper is
connected to the left terminal and the other pole's wiper is connected
to the right.  It should be pretty clear how to wire one of these into
a 3PST switch.

This is as opposed to a "DPDT on-off-on" which leaves the poles
unconnected in the center position.

  -- Don







From uzs159 at uni-bonn.de  Wed Jul  8 22:58:56 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 08 Jul 1998 22:58:56 +0200
Subject: 566 Schematic online
Message-ID: <199807082100.XAA29377@mailhost.bpa.nl>

At 12:00 08.07.1998 -0400, you wrote:
>Hi Rene,
>
>I was looking at your 566 schematic and saw the 2 transistors marked 548
>and 558.. are these just NPN and PNP transistors, respectively? I was
>hoping I could use easy to find parts, such as the 3904 and 3906.

Yes, of course you can use 3904s and 3906s!!!
(The BCs are just easier to find in this part of the world...)

bye

-Ren?

=(uzs159 at uni-bonn.de)========================
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|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
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From uzs159 at uni-bonn.de  Wed Jul  8 23:06:03 1998
From: uzs159 at uni-bonn.de (Rene Schmitz)
Date: Wed, 08 Jul 1998 23:06:03 +0200
Subject: LM566 VCO is alive
Message-ID: <199807082107.XAA29423@mailhost.bpa.nl>

At 07:59 08.07.1998 +0200, you wrote:
>Rene Schmitz wrote:
>> Today I completed the construction of an 566 VCO with expo current control.
>
>Did you think about the possibility of using a XR2206 instead of a 556?
>The 2206 too has a current input for frequency control.

I once mentioned the possibility in (one of the periodic) "ICL8038 as VCO"
threads here.
I think it would work in a very similar way.

>Many years ago I planned a VCO with the 2206 and the expo converter from
>the Formant. But I dropped this as the Curtis chips appeared.

Maybe you should pick it up again.

>Ingo
>
>
=(uzs159 at uni-bonn.de)========================
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|") [" |\ | ["          :   This space 
|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============




From costello at seanet.com  Wed Jul  8 23:11:23 1998
From: costello at seanet.com (Sean Costello)
Date: Wed, 08 Jul 1998 14:11:23 -0700
Subject: Nonlinear Oscillators?
Message-ID: <35A3E07B.E5E49CCD@seanet.com>

Hi all:

Has anyone out there tried to construct a nonlinear oscillator?  By
"nonlinear" I mean an oscillator that behaves like the nonlinear
elements in a traditional musical instrument (like an overblown reed, a
bowed string, etc.).  I would love to have a musical instrument that
could jump octaves like a wind instrument (i.e. with the same sort of
noisy transition, not just clean octave jumps), or generate chaotic
subharmonics like a Gyuto monk, or growl like a sax, or create
multiphonics like an oboe.

Any ideas?  I was thinking that perhaps linear feedback FM could be
used, where the output is fed back through a nonlinear element (like a
full-wave rectifier, or any of the Serge waveshapers, or perhaps
something like the Dual Slope Generator) before going back to the FM
input.  Ideally, the oscillator would be able to track through a
reasonable range under voltage control, and have the nonlinearities
under voltage control to a reasonable degree.  

My little fantasy is to design a TB-303 like box, that retains the
essential features (compact size, battery operated, programmable accent,
programmable slide, diode ladder filter, single oscillator), but with
the capability of creating far more chaotic and complex sounds (octave
jumps, chaotic subharmonics, roughness, growls, squeals, multiphonics).
I would prefer circuitry that emphasized simplicity, cheapness, and
nastiness, instead of precise circuitry that costs more in terms of
money and time.  

I like the idea of the TB-303, but it doesn't sound Kosmische enough for
me.  My ideal box would generate sounds in between Aphex Twin, early
Cluster, Penderecki, Jimi, Ligeti, Neil Young, and the Big Bang.  

Any and all input welcome.  If you know of easy ways to generate the
above sounds, I'd love to hear about it.  I have the feeling that this
might be the place for circuits that didn't work as they were intended
to, but made such an amazing sound that they were used anyway.

Thanks,

Sean Costello

P.S.  I can track down references for nonlinear oscillators in musical
instruments in the next few days, if anyone is interested - I have a few
papers about this that I copied off a few months back. Tonight I'll be
busy installing Linux, so as to run Csound/Cecilia, Common Lisp Music,
and other goodies, but I can create a list in a few days.



From terrymbowman at rica.net  Thu Jul  9 01:31:15 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Wed, 8 Jul 1998 19:31:15 -0400
Subject: ADV Cymbal
Message-ID: <v04003a00b1c9b1689319@[208.1.108.27]>

Just saw the preliminary info on the ADV Cymbal at the MAP site. Looks VERY
interesting, both as a percussion divice and as a ciruit.

http://prairie.lakes.com/%7Emap/cymbal.html

Terry Bowman, KA4HJH
"The Mac Doctor"





From jfoster at lucasdigital.com  Thu Jul  9 01:57:55 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Wed, 08 Jul 1998 16:57:55 -0700
Subject: SERGE banana
References: <3.0.2.16.19980709085327.2adf3ff8@mail.internet-zahav.net>
Message-ID: <35A40783.D165DB85@lucasdigital.com>

the cables are made by Pomona, not sure about the jacks.
The jacks should be common( standard).

good luck,
Jeff

Gur Milstein wrote:

> hi guy's.
> do any body know the manufecture name of the banana used
> in the SERGE system ?
>
> thanx
> Gur Milstein



--
Jeff Foster - 415-662-1254
System/Network Engineer, Skywalkersound, Lucasdigital Ltd.





From sebsi23 at hooked.net  Thu Jul  9 02:11:27 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Wed, 08 Jul 1998 17:11:27 -0700
Subject: SERGE banana
Message-ID: <199807090010.RAA27524@mom.hooked.net>

At 08:53 AM 7/9/98, you wrote:
>hi guy's.
>do any body know the manufecture name of the banana used
>in the SERGE system ?
>
>thanx
>Gur Milstein
>
those would be ITT Pomona. 


Matt Wilson, Odyssey Studios
               on the web: www.wenet.net/~sebsi23
                          on the phone: 415 675-4886
                                    on the email: sebsi23 at hooked.net				
                            




From dslater at ix.netcom.com  Thu Jul  9 02:41:06 1998
From: dslater at ix.netcom.com (Dan Slater)
Date: Wed, 08 Jul 1998 17:41:06 -0700
Subject: Nonlinear Oscillators?
References: <35A3E07B.E5E49CCD@seanet.com>
Message-ID: <35A411A2.7694@ix.netcom.com>

Sean Costello wrote:
> 
> Hi all:
> 
> Has anyone out there tried to construct a nonlinear oscillator?  By
> "nonlinear" I mean an oscillator that behaves like the nonlinear
> elements in a traditional musical instrument (like an overblown reed, a
> bowed string, etc.).  I would love to have a musical instrument that
> could jump octaves like a wind instrument (i.e. with the same sort of
> noisy transition, not just clean octave jumps), or generate chaotic
> subharmonics like a Gyuto monk, or growl like a sax, or create
> multiphonics like an oboe.
> 
> Any ideas?  I was thinking that perhaps linear feedback FM could be
> used, where the output is fed back through a nonlinear element (like a
> full-wave rectifier, or any of the Serge waveshapers, or perhaps
> something like the Dual Slope Generator) before going back to the FM
> input.  Ideally, the oscillator would be able to track through a
> reasonable range under voltage control, and have the nonlinearities
> under voltage control to a reasonable degree.

Hi Sean;

	I have done quite a bit of this type of stuff. I wrote an article on
this topic that is coming out in the next issue of the Computer Music
Journal that you might find interesting. The article is heavily oriented
toward analog techniques and includes a number of chaotic patches for
analog modular synthesizers.

	Anyway it is quite simple to do. You can use the classic chaotic
circuits such as the Ueda Attractor or Chua circuit.

	The mandatory requirement of a chaotic system is a non linear feedback
path. Any system with non linear feedback can go chaotic if there is
sufficient gain. Therefore, the ideas that you proposed above are quite
capable of producing chaotic signals. 

	A simple approach that sounds even better than the classical chaos
circuits is just to cross couple a pair of FM modulated sine wave
oscillators. Simply take oscillator 1 output and FM modulate oscillator
2, similarily take oscillator 2 output and FM modulate oscillator 1.
Make sure that you have adequate gain in the FM paths, if not you will
not be able to get the full spectrum of sounds. You may need to add
amplifiers in the FM paths. The FM inputs are inherently non-linear as
the transfer function is dependent upon the instantaneous oscillator
phase angle. You can get anything from pure sine waves to pure white
noise from this patch. Likewise, "overblown" sounds and octave jumps are
quite easy to get.

	An even simpler variation is just to take a VCO output and run it back
into the FM input. This approach was used in the Yamaha DX-7 as a noise
generator.

Good luck;

Dan Slater (dslater at ix.netcom.com)



From pfperry at melbpc.org.au  Thu Jul  9 03:03:11 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 9 Jul 1998 11:03:11 +1000 (EST)
Subject: Nonlinear Oscillators?
Message-ID: <1.5.4.16.19961130173846.298f8280@popa.melbpc.org.au>

At 02:11 PM 8/07/98 -0700, Sean Costello  wrote:

>bowed string, etc.).  I would love to have a musical instrument that
>could jump octaves like a wind instrument (i.e. with the same sort of
>noisy transition, not just clean octave jumps), or generate chaotic
>subharmonics like a Gyuto monk, or growl like a sax, or create
>multiphonics like an oboe.

well, consider a wavetable synth (any kind, incl. toys.r.us) followed by a 
phase locked loop... these are pretty gnarly with 'real world' inputs..
(or just a freq to v convertor, followed by a Hz/v oscillator, the MS20
external input or the old Korg guitar synth box with the LED rocker switches
will give you an idea)..

If you find any refs please post..
paul perry melbourne australia




From costello at seanet.com  Thu Jul  9 04:11:28 1998
From: costello at seanet.com (Sean Costello)
Date: Wed, 08 Jul 1998 19:11:28 -0700
Subject: Nonlinear Oscillators?
References: <35A3E07B.E5E49CCD@seanet.com> <35A411A2.7694@ix.netcom.com>
Message-ID: <35A426D0.123D8ED6@seanet.com>

Dan Slater wrote:

> Hi Sean;
> 
>         I have done quite a bit of this type of stuff. I wrote an article on
> this topic that is coming out in the next issue of the Computer Music
> Journal that you might find interesting. The article is heavily oriented
> toward analog techniques and includes a number of chaotic patches for
> analog modular synthesizers.

Wow!  When does the next issue come out?  I should probably just get a
subscription (I always put off buying the issues, then get them a few
months after they come out).  By the time the issue is out, I should
have my Nord Modular; hopefully the sort of chaotic patches you describe
can be implemented (I fear that the Nord might err on the tame side, in
order to minimize aliasing).
 
>         An even simpler variation is just to take a VCO output and run it back
> into the FM input. This approach was used in the Yamaha DX-7 as a noise
> generator.

I know that Bernie Hutchins had a circuit that used this technique in
Electronotes - I believe that it was VCO Option 3 in the ENS-76 series -
but that it was discovered that it caused pitch bends that were
unsatisfactory, due to the DC component that developed in the feedback
signal. Still, this is what I had in mind for the TB-303 type circuit:
VCO with linear feedback FM, with feedback running through a non-linear
circuit.  It might be difficult to make the circuit simple and still
retain good pitch accuracy with high amounts of feedback; on the other
hand, who's to say what would sound good in the given application?   

Hmm...isn't Yamaha FM based on phase modulation, as opposed to strict
frequency modulation?  If so, are there any analog oscillator designs
that allow phase to be controlled directly?  Maybe the way to get these
sounds would be to have an allpass network of several stages, where the
phase shift frequency of the network is modulated by the output of the
network.  I always thought that this would be a good way to get a sitar
sound out of a guitar (actually, to simulate a sitar, probably
non-feedback phase modulation is called for, as the sitar spectrum has
tightly clustered harmonic peaks that closely resembles the spectrum
from non-feedback FM, while feedback FM generates a spectrum closer to a
sawtooth wave).  Running the output of the allpass network through a
nonlinear element, then into the modulation input, would also be a
useful experiment.

Also, has anyone tried filter FM, with the modulating signal being the
output of the filter that is run through a nonlinear element (full-wave
rectifier, clipper, suboctave divider, etc.)?  Both the allpass-FM and
filter-FM methods would allow any signal to be run through the circuit,
not just an oscillator.  I wouldn't think that either of these methods
would produce the octave-jumping effect I am after, but I could be very
much wrong.  

Later,

Sean Costello



From dslater at ix.netcom.com  Thu Jul  9 06:51:43 1998
From: dslater at ix.netcom.com (Dan Slater)
Date: Wed, 08 Jul 1998 21:51:43 -0700
Subject: Nonlinear Oscillators?
References: <35A3E07B.E5E49CCD@seanet.com> <35A411A2.7694@ix.netcom.com> <35A426D0.123D8ED6@seanet.com>
Message-ID: <35A44C5F.4EFF@ix.netcom.com>

Sean Costello wrote:
> 
> Dan Slater wrote:
> 
> > Hi Sean;
> >
> >         I have done quite a bit of this type of stuff. I wrote an article on
> > this topic that is coming out in the next issue of the Computer Music
> > Journal that you might find interesting. The article is heavily oriented
> > toward analog techniques and includes a number of chaotic patches for
> > analog modular synthesizers.
> 
> Wow!  When does the next issue come out?  I should probably just get a
> subscription (I always put off buying the issues, then get them a few
> months after they come out).  By the time the issue is out, I should
> have my Nord Modular; hopefully the sort of chaotic patches you describe
> can be implemented (I fear that the Nord might err on the tame side, in
> order to minimize aliasing).
> 

	My understanding is that the CMJ issue should be out any day. I did try
to implement a chaotic FM patch in Kyma during a demo of the system and
found that I was fighting the system. Digital technology is just as
capable of chaos as analog is. Almost all designers of digital systems
have put restrictions in their systems that prevent or limit the use of
chaotic techniques. I do not know if the Nord people put these
restrictions in the system. I did try the same chaotic FM patch on a
Buchla analog modular instrument and in a digital computer and got quite
similar results. This is some of what is written up in the CMJ paper.


> >         An even simpler variation is just to take a VCO output and run it back
> > into the FM input. This approach was used in the Yamaha DX-7 as a noise
> > generator.
> 
> I know that Bernie Hutchins had a circuit that used this technique in
> Electronotes - I believe that it was VCO Option 3 in the ENS-76 series -
> but that it was discovered that it caused pitch bends that were
> unsatisfactory, due to the DC component that developed in the feedback
> signal. Still, this is what I had in mind for the TB-303 type circuit:
> VCO with linear feedback FM, with feedback running through a non-linear
> circuit.  It might be difficult to make the circuit simple and still
> retain good pitch accuracy with high amounts of feedback; on the other
> hand, who's to say what would sound good in the given application?


	What you say would likely work. I have found that the 2 oscillator
chaotic FM patch works quite well and have concentrated on that. I have
added various items into the feedback paths including filters, frequency
shifters, reverbs, etc. These devices all change the character of the
sounds in a variety of ways, some boring, some quite interesting. One of
the most interesting patches occured when I took 4 oscillators and
routed them through a quadraphonic sound swirler. Instead of listening
to the sounds in quad I used the rotator to dynamically route the VCO
outputs to the FM inputs. The result was a set of chaotic dynamically
changing feedback loops.

> 
> Hmm...isn't Yamaha FM based on phase modulation, as opposed to strict
> frequency modulation?  If so, are there any analog oscillator designs
> that allow phase to be controlled directly? 

	Phase and frequency modulation are closely interrelated, essentially
equivalent. Frequency is the time derivative of phase. So a phase
modulated oscillator can be made by passing the FM control signal
through a differentiator (a form of high pass filter) and then into a
standard frequency modulated oscillator.

Good luck;

Dan Slater (dslater at ix.netcom.com)



From martin.czech at intermetall.de  Thu Jul  9 08:03:26 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Thu, 9 Jul 1998 08:03:26 +0200 (MET DST)
Subject: Nonlinear Oscillators?
Message-ID: <199807090603.IAA17807@window.intermetall.de>

> Hmm...isn't Yamaha FM based on phase modulation, as opposed to strict
> frequency modulation?  If so, are there any analog oscillator designs
> that allow phase to be controlled directly?  Maybe the way to get these
> sounds would be to have an allpass network of several stages, where the
> phase shift frequency of the network is modulated by the output of the
> network.  I always thought that this would be a good way to get a sitar
> sound out of a guitar (actually, to simulate a sitar, probably
> non-feedback phase modulation is called for, as the sitar spectrum has
> tightly clustered harmonic peaks that closely resembles the spectrum
> from non-feedback FM, while feedback FM generates a spectrum closer to a
> sawtooth wave).  Running the output of the allpass network through a
> nonlinear element, then into the modulation input, would also be a
> useful experiment.
> 
Sorry folks, I can not suppress this:

Yes (!) this is important, Yamaha uses a phase modulation algo.  I think,
with analogue osc. you can't do it in the same way.  If they have a
linear FM input, well, it's really FM, and as I have learned, Through
Zero Modulation is also important for deep linear FM, most oscillator
designs don't have this feature (see J. Haible's homepage for an
example). The difference between PM and FM becomes evident if you use a
square wave as modulator: The PM carrier jumps in phase, ie. the signal
is non-steady whereas the FM carrier just changes the "speed" of it's
phase rotator, there is distortion of the carrier waveform, but no
jumps.  So, the PM algo will sound brighter than FM. And another fact
is that PM remains at the same phase modulation depth if the modulator
frequency moves far away from the carrier, with FM the phase modulation
depth will decrease with - i think - -6dB per octave. Simple
experiment: try different ratios with a Yamaha "FM" instrument and then
try this with analogue gear (of course sine wave output !) and you'll
hear how the carrier will get closer to the original sine shape, if the
modulator moves away in the later case.  On the other hand, slow PM and
slow FM cause vibrato, but in the case of FM the vibrato depth remains
constant, no matter how slow it is (of course dc-coupled fm input
required for this !) whereas PM gets inaudible if slow enough.

For the math lovers out there:
                             _
f(t)=d/dt phi(t) or phi(t)= / f(t) dt + c
                           -
ie. frequency is the time derivation of phase, or the other way
arround: phase is the integral of frequency plus some constant (initial
value). Now, this shows how the above mentioned observations can be
explained. Remember, integration is some kind of low pass filter.

And writing this it comes to my mind, that above statement "amalogue PM
is not possible" is obviously not true, the second formula above shows
what to do: The analogue FM input is integrated by the oscillator, to
reverse this operation, we have to use a differentiator (spelling ?) If
you have an analogue osc. with linear FM input and Trough Zero
Modulation, just insert a differentiator before the FM input. Viola!  The
problem is, a *real* differentiator is not possible, you can only
approximate it. And differentiation means: raising the noise floor.  In
generall this all means using filters before the FM input of analogue
gear. You allready have this idea in mind.


> Also, has anyone tried filter FM, with the modulating signal being the
> output of the filter that is run through a nonlinear element (full-wave
> rectifier, clipper, suboctave divider, etc.)?  Both the allpass-FM and
> filter-FM methods would allow any signal to be run through the circuit,
> not just an oscillator.  I wouldn't think that either of these methods
> would produce the octave-jumping effect I am after, but I could be very
> much wrong.  
> 
Well, I know that PM causes octave -sliding- not jumping.  Imagine
carrier and operator with ratio 1:1, it is obvious that a some point of
modulation depth the fundamental is inaudible and the second harmonic is
very strong (Bessel functions).

Another interesting way to go is sync. I mean syncing is a way of PM,
and it is nonlinear and easy to do. This would require a switch (mosfet
etc) that sets the oscillator to some predefined (or even better
voltage controlled) level if triggered.  One could add a window
comparator that enables sync only under some condition , eg. osc level
above 75% (this is called weak sync) or master osc between 10% and
20%.  If the loop is closed (ie. two osc.  sync each other) this could
get pretty chaotic. Sweeping osc. with sync can easily jump into
another octave, or another harmonic, if you use strong sync. I remember
a sound from Reinhold Heil (Splif, "Schwarz auf Weiss" ?), where this
feature is used (Oberheim, Prophet ?). I'm still after this sound.
If you use weaker sync, more "dirt" is produced.

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 batzman at all-electric.com  Thu Jul  9 09:19:40 1998
From: batzman at all-electric.com (The Dark force of dance)
Date: Thu, 9 Jul 1998 16:49:40 +0930
Subject: 27c010 eprom blaster
Message-ID: <2.2.16.19980709164252.385f1002@mail.chariot.net.au>

Y-ellow Y'all.
        I know this is probably a long shot but does anyone relatively local
to me have an eprom blaster that can do a 27C010? I have a dead laptop of
which I believe the eprom is dead. (I mean when some dick-head inserts 'em
in backwards they tend to be toast.) I have one-only good copy of the eprom.
If I loose that then I have two dead lap-tops. They're a piece of crap
anyway and I got ripped off on them badly. But the only way I'm gonna find
out if I can use the second one in any capacity is by getting a new copy of
the eprom.


I bought them from Paul <pg at logicworld.com.au> (Warning Warning danger Will
Robinson) and they were supposed to be 386s in V-good condition blah blah
blah. When I got them they turned out to be 286s in very-stuffed condition.
Now, in order to try and at least redeem something of this little scam, I'm
trying to revive them to use as intelligent LCD displays. Not that the
displays are very good either. :( They have a latency of about 3 weeks.

But they're not much good to use for what I bought them for. To use them as
lap-tops. I have an eprom blaster but it only handles up to 27c512. I tried
to dump the BIOS to a file but the software I have doesn't seem to
understand files of that size. So if anyone can help me out here I would
appreciate it muchley.

Thanks in advance.

Be Absolutely Icebox.
 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The new AEK CD, Elementary Urban sanity    
| |_) | (_| | |_  / /   is out now on Transmission Communications from
|_,__/ \__,_|\__|/ /    http://brisbane.dialix.com.au:80/~com11
                / ,__   and check out http://www.all-electric.com
Goodfortune    |_____|       Let your SANITY wear thin.




From gur-m at internet-zahav.net  Thu Jul  9 08:53:27 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Thu, 09 Jul 1998 08:53:27
Subject: SERGE banana
Message-ID: <3.0.2.16.19980709085327.2adf3ff8@mail.internet-zahav.net>

hi guy's.
do any body know the manufecture name of the banana used
in the SERGE system ?

thanx
Gur Milstein



From tomg at vivid.net  Thu Jul  9 11:04:26 1998
From: tomg at vivid.net (tomg)
Date: Thu, 09 Jul 1998 04:04:26 -0500
Subject: Mini1cv Online (preliminary)
Message-ID: <yam7494.1310.120427976@mail.vivid.net>

The Mini1cv brings me full circle and is based on the first synth I ever built
(which was based on a single Oberheim Matrix-12 voice). I never posted the
Mini1 because it is full of chips made by Curtis Electronics and as far as I
knew were no longer available. Well, time has passed and things have changed.
Synthesis Technology at www.synthtech.com now has all chips in stock. 

1 CEM3374  15.00
1 CEM3372  15.00
2 CEM3310  32.00

The Mini1cv is a standard normalized synth on a 4X6" pc board. Only 8 chips
for the whole thing.It's easy to build reasonable in cost and sounds terrific.


This is a preliminary posting. The circuits have all been tested but I just
started putting it all together. I'm sure I'll tweek this before I'm done. I
posted it for people who were interested in the 3374 VCO and may want to buy a
3372 and a couple of 3310s while they're at it. I will finish over the weekend
and post changes then.

-Tom

http://www.tomg.vivid.net/mini1/title.html





From blacet at metro.net  Thu Jul  9 11:28:18 1998
From: blacet at metro.net (John Blacet)
Date: Thu, 09 Jul 1998 09:28:18 +0000
Subject: LM566, IC8038, Fatman CVs
References: <199807082107.XAA29423@mailhost.bpa.nl> <3.0.1.32.19980709090501.00941760@uxsfo4.fritz.com>
Message-ID: <35A48D31.6474@metro.net>

Regarding the 8038 as a function generator; there are some tricks to
getting it to work, but work it does. See the App note below:

http://www.semi.harris.com/data/an/an0/an013/index.htm
-- 

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



From H.J.vanderlinden at stud.far.ruu.nl  Thu Jul  9 14:42:39 1998
From: H.J.vanderlinden at stud.far.ruu.nl (Heiko van der Linden)
Date: Thu, 09 Jul 1998 14:42:39 +0200
Subject: scanning keyboards
Message-ID: <35A4BABE.F108DF46@stud.far.ruu.nl>

HI,
I'm currently working on a tb-303 clone and I'm trying to replace the
microcontroller with a z80 based system, but I have a problem: how do
you scan the keyboardmatrix and the ledmatrix? I have read several books
on z80 programming but none of the books I've read give any clues about
scanning keyboards with a z80. Does anyone know if there are books on
this or a net resource.
Thanks Heiko




From b.layer at vikingelectronics.com  Thu Jul  9 15:38:59 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 09 Jul 1998 08:38:59 -0500
Subject: LM566, IC8038, Fatman CVs
In-Reply-To: <199807082107.XAA29423@mailhost.bpa.nl>
Message-ID: <3.0.5.32.19980709083859.007abbd0@192.168.210.18>

>I once mentioned the possibility in (one of the periodic) "ICL8038 as VCO"
>threads here.
>I think it would work in a very similar way.
>
Is this the Harris IC8038 - VCO chip with sine, tri, pulse? I've been given
a couple by one of our engineers, he thought they would be great for emusic
apps. I was planning to use one possibly as a VC/LFO for the tube synth.

Another subject: The FatMan produces V/Hz pitch CV output. This is
necessary as it's VCO's are essentially just linear response
voltage-to-current converters (current sourcing a relaxation oscillator).
Log CV is required for tempered pitch.

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From pfperry at melbpc.org.au  Thu Jul  9 17:14:07 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 10 Jul 1998 01:14:07 +1000 (EST)
Subject: LM566, IC8038, Fatman CVs
Message-ID: <1.5.4.16.19961201074945.36ffaa9c@popa.melbpc.org.au>

At 08:38 AM 9/07/98 -0500, Bill Layer wrote:

>Is this the Harris IC8038 - VCO chip with sine, tri, pulse? I've been given
>a couple by one of our engineers, he thought they would be great for emusic
>apps. I was planning to use one possibly as a VC/LFO for the tube synth.
....yes it is.
I suppose it would be usefulk for a 'tube' synth as it uses damn near as much
current as a tube! ;-)
Harris run a 'fax back' touch phone input data service, by which it is
possible to get
12 or so pages trying (in not so many words) to tell you how to get the 8038
anywhere near what you would want, range and symmetry/dstortion wise.
I wouldn't use it for anything but a lfo personally.

paul perry melbourne australia
(just back from the Clan Analog night at the Punters)




From scott.bernardi at fritz.com  Thu Jul  9 18:05:01 1998
From: scott.bernardi at fritz.com (Scott Bernardi)
Date: Thu, 09 Jul 1998 09:05:01 -0700
Subject: LM566, IC8038, Fatman CVs
In-Reply-To: <3.0.5.32.19980709083859.007abbd0@192.168.210.18>
References: <199807082107.XAA29423@mailhost.bpa.nl>
Message-ID: <3.0.1.32.19980709090501.00941760@uxsfo4.fritz.com>

The 8038 is the Intersil/Harris chip, and I have yet to hear of anyone that
has successfully built a musical VCO with it. It requires matched current
sources (ie, pnp's)  to drive it. I tried to breadboard just a function
generator circuit using it, and couldn't get it to work right.
The XR2206 driven by an exponential current sink (ie, npn's) is a much
better way to go.

At 08:38 AM 7/9/98 -0500, you wrote:
>>I once mentioned the possibility in (one of the periodic) "ICL8038 as VCO"
>>threads here.
>>I think it would work in a very similar way.
>>
>Is this the Harris IC8038 - VCO chip with sine, tri, pulse? I've been given
>a couple by one of our engineers, he thought they would be great for emusic
>apps. I was planning to use one possibly as a VC/LFO for the tube synth.
>
>Another subject: The FatMan produces V/Hz pitch CV output. This is
>necessary as it's VCO's are essentially just linear response
>voltage-to-current converters (current sourcing a relaxation oscillator).
>Log CV is required for tempered pitch.
>
>------------------------------
>Bill Layer
>Sales Technician
>
>Viking Electronics, Inc.
>1531 Industrial St.
>Hudson, WI 54016
>
>Phone: (715)386-8861 Ext. 210
>Fax: (715)386-4344
>E-mail: b.layer at vikingelectronics.com
>
>http://www.vikingelectronics.com
>24 Hour Fax Back System: (715)386-4345
>
>
--------------------------------------
Scott Bernardi
voice: 415-538-0439 
fax:   415-904-8375
scott.bernardi at fritz.com



From jfoster at lucasdigital.com  Thu Jul  9 18:16:29 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Thu, 09 Jul 1998 09:16:29 -0700
Subject: Nonlinear Oscillators?
References: <35A3E07B.E5E49CCD@seanet.com> <35A411A2.7694@ix.netcom.com> <35A426D0.123D8ED6@seanet.com> <35A44C5F.4EFF@ix.netcom.com>
Message-ID: <35A4ECDD.8E7453F4@lucasdigital.com>

hi all,
love this subject !

I wounder if there is a way to do FM on the tube synth vco( by Eric) posted here a bit
ago?
Tubes are non-linear to some degree and combining this with crossed patched FM might
lead to a
good sounding chaotic soud system generator.

Is it possible to add FM control to the tube vco? Can the existing sync in be used
some how?

just thoughts,
Jeff

--
Jeff Foster - 415-662-1254
System/Network Engineer, Skywalkersound, Lucasdigital Ltd.





From b.layer at vikingelectronics.com  Thu Jul  9 18:48:04 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 09 Jul 1998 11:48:04 -0500
Subject: LM566, IC8038, Fatman CVs
In-Reply-To: <1.5.4.16.19961201074635.36ff3634@popa.melbpc.org.au>
Message-ID: <3.0.5.32.19980709114804.007ac9d0@192.168.210.18>

>I suppose it would be usefulk for a 'tube' synth as it uses damn near as much
>current as a tube! ;-)

Do you mean current or power? Typical Ik (cathode current) for a small
signal amplifier tube is 1-3mA. With a nominal voltage drop of 150VDC, the
tube would dissipate about 3/10 of a watt. Include a 6.3VAC heater @ 300mA,
and you've got a total heat rejection of 2.2W for a typical small device.



------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From stan at record.globalnet.co.uk  Thu Jul  9 20:47:04 1998
From: stan at record.globalnet.co.uk (Matthew S. Padden)
Date: Thu, 9 Jul 1998 19:47:04 +0100
Subject: Fans and switched mode PSUs
Message-ID: <000001bdab6a$96600480$646464c8@miles>

Hi..

    Question: how badly do the switch mode PSUs you get in external drive cases need their small , noisy, and intrusive fans? I'm thinking of using one as a PSU for some ccts (Yes, I know they give out interference like a small star).

I was thinking of:

a) dispense with the fan altogether; I won't be pushing the PSU hard at all.

b) swap the fan for a thermally controlled 'low-noise' replacement. The best noise figure I've seen for these is 24dBA, from Farnell in the UK.

Any advice appreciated

Matthew S. Padden
Leeds, UK
mattp at mindless.com

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From planet4 at swipnet.se  Thu Jul  9 21:21:59 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Thu, 09 Jul 1998 21:21:59 +0200
Subject: question about audio OP amp
Message-ID: <35A51857.83E610C5@swipnet.se>

Hi all!

As a novice in the art of OP's, I used the TL072 as an audio OP in a
Paia Fatman mod and I'm not really sure about this... Has anyone any
suggestions to a simple, good OP to use with audio?
Thanks for help!

Johan





From aschrock at cs.brandeis.edu  Thu Jul  9 22:20:08 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Thu, 9 Jul 1998 16:20:08 -0400 (EDT)
Subject: question about audio OP amp
In-Reply-To: <35A51857.83E610C5@swipnet.se>
Message-ID: <Pine.SGI.3.95.980709161259.1102D-100000@peridot.cs.brandeis.edu>

On Thu, 9 Jul 1998, Johan Persson wrote:
> As a novice in the art of OP's, I used the TL072 as an audio OP in a
> Paia Fatman mod and I'm not really sure about this... Has anyone any
> suggestions to a simple, good OP to use with audio?

Johan,

You should be fine using any garden-variety op-amp.. TL082, TL072, even a
741 would be fine. I use TL082's since they're cheap, decent quality, and
is a dual vs. a single. 

Are you working on the audio input mod? If so IMO it's cool to decrease
the value of a critical resistor (marked r_gain on scott's mod gif) to
overdrive the circuit slightly. I have mine overdriving my input by maybe
a factor of 2, so that when the ex. in volume is up all the way the input
sound slightly distorts, but when it's at 1/2 the sound is just filtered
normally. Handy! 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From ebarbour at svetlana.com  Thu Jul  9 23:25:28 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 9 Jul 1998 14:25:28 -0700
Subject: FMing of VCO
Message-ID: <01BDAB45.6C38D940.ebarbour@svetlana.com>


>I wonder if there is a way to do FM on the tube synth vco (by Eric)
>posted here a bit ago?

Yes. Just:
--build two VCOs (their outputs are weird-looking sawtooth waveforms)
--connect input of each to an op-amp driver so you can mix 2 or more CVs together.
--Then take one VCO's output, run thru a 10-1 voltage divider (to protect the
      op-amp from damage by the high voltages the VCO thyratrons make)
--and run it into the input op-amp of the other VCO. 
--Do vice versa for cross-coupling.


>Tubes are non-linear to some degree

That, sir, is a FALLACY. You have been reading the incoherent and
ignorant statements made by half-baked designers who don't know
any better. Many of them have never actually tested a variety of
tubes for distortion. They make this kind of statement based on the
cheap, low-quality 12AX7s (which is the only tube type they are familiar with)
which they tend to use in their cheap, sleazy audio processors.

In fact, some small-signal triodes are MORE LINEAR THAN ANY
AVAILABLE TRANSISTOR.

	I CAN PROVE IT!!! Any takers? 

The tubes used in these VCOs are nonlinear, which makes them
useful for unique FM behavior. A low-distortion tube VCO IS possible.......


>combining this with crossed-patched FM might lead to a
>good sounding chaotic sound system generator.

In fact, I've done this with my experimental modular system. It works
amazingly well, and VERY strange things happen as you change the
tunings of the two VCOs.

>Can the existing sync in be used some how?

Yes, but you would have better results by mixing CVs with
an input op-amp, then going to the grids of the thyratron.







From sasami at blaze.net.au  Thu Jul  9 23:40:48 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Thu, 9 Jul 1998 23:40:48 +0200 (MET DST)
Subject: Fans and switched mode PSUs
Message-ID: <199807092140.XAA17445@mailhost.bpa.nl>

>    Question: how badly do the switch mode PSUs you get in external drive
cases need their small , noisy, and intrusive fans? I'm thinking of using
one as a PSU for some ccts (Yes, I know they give out interference like a
small star).

Very badly. Kill the fan, you cook the supply. Since you are only lightly
loading it, consider putting a few diodes in series with the fan voltage
(assuming it's a 12 v fan) and reduce its speed and noise that way.

>a) dispense with the fan altogether; I won't be pushing the PSU hard at all.

bad idea. I've seen major damage result when fans have failed. Cooked filter
capacitors  for example.

>b) swap the fan for a thermally controlled 'low-noise' replacement. The
best noise figure I've seen for these is 24dBA, from Farnell in the UK.

possible.

Best idea:  Use linear power supply.

Ken (the hypocrite, who does have a switchmode in one of his modules.) 

_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From brucejd at interlog.com  Thu Jul  9 23:45:59 1998
From: brucejd at interlog.com (bruce duncan)
Date: Thu, 9 Jul 1998 17:45:59 -0400 (EDT)
Subject: SERGE banana
Message-ID: <199807092145.RAA25896@smtp.interlog.com>

At 08:53 AM 7/9/98, you wrote:
>hi guy's.
>do any body know the manufecture name of the banana used
>in the SERGE system ?
>
>thanx
>Gur Milstein

I think his name is Rex Probe

Just kidding............ Pomona Electronics in California
 






From scott.bernardi at fritz.com  Fri Jul 10 00:09:39 1998
From: scott.bernardi at fritz.com (Scott Bernardi)
Date: Thu, 09 Jul 1998 15:09:39 -0700
Subject: question about audio OP amp
In-Reply-To: <Pine.SGI.3.95.980709161259.1102D-100000@peridot.cs.brandei
 s.edu>
References: <35A51857.83E610C5@swipnet.se>
Message-ID: <3.0.1.32.19980709150939.0094c960@uxsfo4.fritz.com>

Depending on what voltage levels you are driving to, a 741 can give you
distortion because of slew rate limiting (0.5v/usec slew rate). An opamp
needs about 1.5v/usec to run to 20khz at +/10v levels. All of the TL-
opamps are FET based, which have higher slew rates.


At 04:20 PM 7/9/98 -0400, you wrote:
>On Thu, 9 Jul 1998, Johan Persson wrote:
>> As a novice in the art of OP's, I used the TL072 as an audio OP in a
>> Paia Fatman mod and I'm not really sure about this... Has anyone any
>> suggestions to a simple, good OP to use with audio?
>
>Johan,
>
>You should be fine using any garden-variety op-amp.. TL082, TL072, even a
>741 would be fine. I use TL082's since they're cheap, decent quality, and
>is a dual vs. a single. 
>
>Are you working on the audio input mod? If so IMO it's cool to decrease
>the value of a critical resistor (marked r_gain on scott's mod gif) to
>overdrive the circuit slightly. I have mine overdriving my input by maybe
>a factor of 2, so that when the ex. in volume is up all the way the input
>sound slightly distorts, but when it's at 1/2 the sound is just filtered
>normally. Handy! 
>
>Andrew
>
>| Andrew Schrock							|
>| Network Programmer, Synthesizer and electronic music enthusiast	|
>| aschrock at cs.brandeis.edu						|
>
>
>
>
>
--------------------------------------
Scott Bernardi
voice: 415-538-0439 
fax:   415-904-8375
scott.bernardi at fritz.com



From chordman at flash.net  Fri Jul 10 00:59:39 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Thu, 09 Jul 1998 22:59:39 GMT
Subject: question about audio OP amp
In-Reply-To: <Pine.SGI.3.95.980709161259.1102D-100000@peridot.cs.brandeis.edu>
References: <Pine.SGI.3.95.980709161259.1102D-100000@peridot.cs.brandeis.edu>
Message-ID: <35a84a70.69052175@mail.lan>

On Thu, 9 Jul 1998 16:20:08 -0400 (EDT), Andrew Schrock
<aschrock at cs.brandeis.edu> wrote:

>On Thu, 9 Jul 1998, Johan Persson wrote:
>> As a novice in the art of OP's, I used the TL072 as an audio OP in a
>> Paia Fatman mod and I'm not really sure about this... Has anyone any
>> suggestions to a simple, good OP to use with audio?
>
>Johan,
>
>You should be fine using any garden-variety op-amp.. TL082, TL072, even a
>741 would be fine. I use TL082's since they're cheap, decent quality, and
>is a dual vs. a single. 
>
>Are you working on the audio input mod? If so IMO it's cool to decrease
>the value of a critical resistor (marked r_gain on scott's mod gif) to
>overdrive the circuit slightly. I have mine overdriving my input by maybe
>a factor of 2, so that when the ex. in volume is up all the way the input
>sound slightly distorts, but when it's at 1/2 the sound is just filtered
>normally. Handy! 

Mind if I pipe in?  <g>  r_gain can be a variable resistor (pot) wired
like a rheostat like mine (use the center pin and one side, making
sure that when fully clockwise you get max resistance).  I didn't draw
it that way because pots are more expensive than fixed Rs and panel
space is always a problem.  My unit actually has a gain pot and a
level pot.  The gain pot goes from a gain of 1 to around 450 when wide
open.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From aschrock at cs.brandeis.edu  Fri Jul 10 01:26:18 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Thu, 9 Jul 1998 19:26:18 -0400 (EDT)
Subject: question about audio OP amp
In-Reply-To: <3.0.1.32.19980709150939.0094c960@uxsfo4.fritz.com>
Message-ID: <Pine.SGI.3.95.980709192407.18894A-100000@opal.cs.brandeis.edu>

On Thu, 9 Jul 1998, Scott Bernardi wrote:
> Depending on what voltage levels you are driving to, a 741 can give you
> distortion because of slew rate limiting (0.5v/usec slew rate). An opamp
> needs about 1.5v/usec to run to 20khz at +/10v levels. All of the TL-
> opamps are FET based, which have higher slew rates.

Am I mistaken, or do some people claim they can hear the difference
between 741's and other more modern opamps and prefer the sound of the
741's? I've heard this mentioned before... Any evidence to back this claim
up? 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From jfoster at lucasdigital.com  Fri Jul 10 02:23:51 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Thu, 09 Jul 1998 17:23:51 -0700
Subject: FMing of VCO
References: <01BDAB45.6C38D940.ebarbour@svetlana.com>
Message-ID: <35A55F17.F759724A@lucasdigital.com>



Eric Barbour wrote:

> >I wonder if there is a way to do FM on the tube synth vco (by Eric)
> >posted here a bit ago?
>
> Yes. Just:
> --build two VCOs (their outputs are weird-looking sawtooth waveforms)
> --connect input of each to an op-amp driver so you can mix 2 or more CVs together.
> --Then take one VCO's output, run thru a 10-1 voltage divider (to protect the
>       op-amp from damage by the high voltages the VCO thyratrons make)
> --and run it into the input op-amp of the other VCO.
> --Do vice versa for cross-coupling.

ok, thanks for the suggestion, I'll take this into account while I design the front
panel
of my tube based unit (1 vco, 1 bpf, 1 vca) now I have to make room for a second vco..

>
>
> >Tubes are non-linear to some degree
>
> That, sir, is a FALLACY. You have been reading the incoherent and
> ignorant statements made by half-baked designers who don't know
> any better.

nope, I have never read any tube statements except the ones posted here.I have only
looked and to some degree understood the schema present here as well,
regarding tube circuts.

I am under the impression that the "tube sound" is in part caused by there non
linearity.
I guess I am wrong or confused or both :-)

hope the book idea regarding tubes ( as noted on the Engineering musician site)
happens,
I could use it.



> Many of them have never actually tested a variety of
> tubes for distortion. They make this kind of statement based on the
> cheap, low-quality 12AX7s (which is the only tube type they are familiar with)
> which they tend to use in their cheap, sleazy audio processors.
>

I'll take your word for it.

> In fact, some small-signal triodes are MORE LINEAR THAN ANY
> AVAILABLE TRANSISTOR.
>
>         I CAN PROVE IT!!! Any takers?



> The tubes used in these VCOs are nonlinear, which makes them
> useful for unique FM behavior. A low-distortion tube VCO IS possible.......
>

so the nonlinear nature is in the type of tube, but no tubes in general. That is,
onecan design for degrees of non linearity?

feel free to educate me further, but be kind ;-)

> >combining this with crossed-patched FM might lead to a
> >good sounding chaotic sound system generator.
>
> In fact, I've done this with my experimental modular system. It works
> amazingly well, and VERY strange things happen as you change the
> tunings of the two VCOs.
>
> >Can the existing sync in be used some how?
>
> Yes, but you would have better results by mixing CVs with
> an input op-amp, then going to the grids of the thyratron.

thank for the ideas and clarifications Eric,

JEff

--
Jeff Foster - 415-662-1254
System/Network Engineer, Skywalkersound, Lucasdigital Ltd.





From pfperry at melbpc.org.au  Fri Jul 10 03:20:58 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 10 Jul 1998 11:20:58 +1000 (EST)
Subject: CV-VCAs
Message-ID: <1.5.4.16.19961201175640.37bf48a0@popa.melbpc.org.au>

At 09:37 PM 10/07/98 +0300, you wrote:
>I was thinking to put VCAs in my Modular under
>construction, that can control Envelope/LFO/etc..
>amount fed to VCF/VCA/etc... 
>
>So the question is: can this be done with any VCA? 

yes.....IF the VCA works at DC levels.
That is to say, some VCA ckts have capacitors in the signal path.
Well, these won't work for very low frequency signal changes.

paul perry melbourne australia




From chordman at flash.net  Fri Jul 10 05:23:18 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 10 Jul 1998 03:23:18 GMT
Subject: question about audio OP amp
In-Reply-To: <35a84a70.69052175@mail.lan>
References: <Pine.SGI.3.95.980709161259.1102D-100000@peridot.cs.brandeis.edu> <35a84a70.69052175@mail.lan>
Message-ID: <35b288db.85034277@mail.lan>

On Thu, 09 Jul 1998 22:59:39 GMT, chordman at flash.net (Scott
Gravenhorst) wrote:

>Mind if I pipe in?  <g>  r_gain can be a variable resistor (pot) wired
>like a rheostat like mine (use the center pin and one side, making
>sure that when fully clockwise you get max resistance).  I didn't draw
>it that way because pots are more expensive than fixed Rs and panel
>space is always a problem.  My unit actually has a gain pot and a
>level pot.  The gain pot goes from a gain of 1 to around 450 when wide
>open.

Oh yes, in series with the gain pot, put a fixed resistor equal to the
input resistor, otherwise some of the gain pots rotation will be
wasted as gain of 1 until it's resitance goes above whatever the input
R is.  I have a 2 meg pot in series with a 4.7k fixed R because my
input R is 4.7k.  A small difference, but it allows full use of the
pot.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From shudder at optusnet.com.au  Fri Jul 10 07:47:20 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Fri, 10 Jul 1998 15:47:20 +1000
Subject: wasp (was: Re: [sdiy] Comparator = Opamp ??)
Message-ID: <006501bdabc6$35862520$4b2d8ec6@dialup.mpx.com.au>

>> If you take that filter *out* of the Wasp, however, to use it for complex
>> signals (rather than two raw VCOs), the unique distortion character
>> becomes prominent. Especially when you're adding some extra distortion
>> stages from the remaining buffers of a 4069 package.
>> (There were some guitar fuzz boxes designed around CMOS chips
>> as well, but I don't remember which ones.)
>
>EH Hot Tubes
>also designs from Craig Anderton...

I also like this one:
http://hail-eris.com/~stompbox/pedals/schematics.html#anch_insanity
Have a listen to the hard rocker doing the first sound sample, I bet his
hair's long and his jeans' tight!

Sean




From Juergen.Haible at nbgm.siemens.de  Fri Jul 10 12:17:25 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 10 Jul 1998 12:17:25 +0200
Subject: AW: Nonlinear Oscillators?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827FAE7D@nbgm336a.nbgm.siemens.de>

	>Has anyone out there tried to construct a nonlinear oscillator?  By
	>"nonlinear" I mean an oscillator that behaves like the nonlinear
	>elements in a traditional musical instrument (like an overblown
reed, a
	>bowed string, etc.).  I would love to have a musical instrument
that
	>could jump octaves like a wind instrument (i.e. with the same sort
of
	>noisy transition, not just clean octave jumps), or generate chaotic
	>subharmonics like a Gyuto monk, or growl like a sax, or create
	>multiphonics like an oboe.
	>
	>Any ideas? 

The first ideas I have to offer have probably nothing to do with 
"nonlinear oscillators", but with the smooth octaves transition
you mentioned (overblow etc.)

Fist, there is the good old Sync. To some extend, it does just
this, a smooth waveform transistion without getting nonharmonic,
between several harmonics. Problem might be that it also has such
a distinct "sync" sound, that it must be considered as a separate
effect of its own. However, the other than the "normal" hard sync 
schemes can be refreshing here. Try the EMS sync as described
on Graham Hinton's Page, it sounds *very* interesting, especially
when applied on the sine waveform.

Second, wavetable synths can do a crossfade between octaves.
It was either the Wiard or the Modcan that has a module to do
this. The "overblow" effect is mentioned.

Third, you can do wonderful things in that domain with triangle 
waveshaping. We had some discussion of certain Serge modules
recently, and I have posted some applications of my IS that go
in the same direction. If you feed a triangle wave into a "zigzag"
courve (consisting of separate triangles functions) with varying
drive amplitudes, you get a very nice "overblow" effect.
Funny, but I have a special instrument in mind right now that might
be a new diy project of mine, and I wrote to Magnus about it earlier
this week. Here's an excerpt: 
====
There is one thing I have in mind as a future project (but it's in
a very early stage): 
I want to have one large knob to play "fretless" within a 1 octave
range (like an ordinary laboratory function generator).
Then I will have a second knob (or slider, or lever) to fade between
octaves, using a Scanner. The octaves themselves would be 
generated by waveshaping. This should be easy when I stick to
triangle waves. These triangele waves will then be formed to
complex waveforms at the output.
My intention is to get a control that is fine enough to hit notes
precisely (large knob, 1 octave range), and still be able to
change notes fast (maximum 270 degree turn for the note, and
a few millimeters on a slider for the octaves).
An alternative for choosing octaves would be a set of fast responding
buttons, but the continuous scanning might also give interesting
overblow effects.
What do you think ?
====

>Also, has anyone tried filter FM, with the modulating signal being the
>output of the filter that is run through a nonlinear element (full-wave
>rectifier, clipper, suboctave divider, etc.)?  Both the allpass-FM and
>filter-FM methods would allow any signal to be run through the circuit,
>not just an oscillator.  I wouldn't think that either of these methods
>would produce the octave-jumping effect I am after, but I could be very
>much wrong.  

I didn't get octave jumps, but the method is extremely rewarding,
nevertheless.
On my CS-50, I have the main audio output plugged into the
"external in" all the time, so the audio output is available for
all modulations that the LFO ("sub oscillator" in Yamaha speak)
could do. I use it regularly to modulate the filter, and also the VCA,
and it is great to create a complex attack phase on an otherwise
boring sound. For example, the "Flute" preset becomes a trumpet
sound that rivals the VL7 in expression (and leaves it far behind
in terms of warmth), just with a little VCA modulation from the audio
output.
Larger modulation depths cause chaotic sounds, but the interesting
region is just "close to the edge". BTW, though I never exactly
analyzed this behaviour, but if memory serves the external input
of the CS-50 is ac coupled and I have it set to mic level (the trimpot
is a little hard to move on mine), so ther is probably some linear and
nonlinear processing in the feedback loop.
Might be interesting to evaluate this further on the Modular.

JH.
 



From Juergen.Haible at nbgm.siemens.de  Fri Jul 10 12:35:41 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 10 Jul 1998 12:35:41 +0200
Subject: linear devices ?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827FAEB6@nbgm336a.nbgm.siemens.de>

	>> Tubes are non-linear to some degree
	> That, sir, is a FALLACY.
	[...]
	> In fact, some small-signal triodes are MORE LINEAR THAN ANY
	> AVAILABLE TRANSISTOR.
	> I CAN PROVE IT!!! Any takers? 

I'm surprised. I thought that every tube is nonlinear to some degree,
and that even a cheap ECC83 is still more linear than a (bjt)  tansistor.
It would be hard to deny the first one, and running in open doors
to proove the second one.

Linearity can either be approximated by using several devices and
close feedback (with the negative side effects we all know from
overdriven opamps), or by making a single device closer to the linear
ideal. I am ready to believe that this works better for tubes.
Is that what you mean ?

JH.




From kimmo at ecdl.hut.fi  Fri Jul 10 12:54:49 1998
From: kimmo at ecdl.hut.fi (Kimmo Koli)
Date: Fri, 10 Jul 1998 13:54:49 +0300 (EETDST)
Subject: AW: Nonlinear Oscillators?
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5827FAE7D@nbgm336a.nbgm.siemens.de>
Message-ID: <Pine.HPP.3.96.980710133835.10121A-100000@ecdl.hut.fi>

Well, 
I remember a conference paper in ISCAS?96 in Atlanta where if I remember
correctly Edgar Sanchez-Sinencios's research group had designed a chaotic
oscillator based on a state-variable filter. It had the normal
negative feedback path for Q-tuning but also a comparator with hysteresis
as an additional feedback. That would be an easy addition to a standard
analog VCF. Probably with suitable feedback value it could add some kind
of a chaotich sub-osc to an normal synth sound. And also this chaotic VCF
could be used as a VCO.  

Unfortunately I'm not reading my emails at least for a week due to summer
holidays. So if You want to ask someting more about this, the answering 
may take some time....

Best regards, Kimmo Koli

On Fri, 10 Jul 1998, Haible Juergen wrote:
> 
> >Also, has anyone tried filter FM, with the modulating signal being the
> >output of the filter that is run through a nonlinear element (full-wave
> >rectifier, clipper, suboctave divider, etc.)?  Both the allpass-FM and
> >filter-FM methods would allow any signal to be run through the circuit,
> >not just an oscillator.  I wouldn't think that either of these methods
> >would produce the octave-jumping effect I am after, but I could be very
> >much wrong.  
> 
> I didn't get octave jumps, but the method is extremely rewarding,
> nevertheless.
> On my CS-50, I have the main audio output plugged into the
> "external in" all the time, so the audio output is available for
> all modulations that the LFO ("sub oscillator" in Yamaha speak)
> could do. I use it regularly to modulate the filter, and also the VCA,
> and it is great to create a complex attack phase on an otherwise
> boring sound. For example, the "Flute" preset becomes a trumpet
> sound that rivals the VL7 in expression (and leaves it far behind
> in terms of warmth), just with a little VCA modulation from the audio
> output.
> Larger modulation depths cause chaotic sounds, but the interesting
> region is just "close to the edge". BTW, though I never exactly
> analyzed this behaviour, but if memory serves the external input
> of the CS-50 is ac coupled and I have it set to mic level (the trimpot
> is a little hard to move on mine), so ther is probably some linear and
> nonlinear processing in the feedback loop.
> Might be interesting to evaluate this further on the Modular.
> 
> JH.
>  
> 

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
   Kimmo Koli                         Helsinki University of Technology 
   kimmo at ecdl.hut.fi                  Electronic Circuit Design Laboratory
   http://www.ecdl.hut.fi/~kimmo      P.O.Box 3000
   Tel:  +358 9 451 2273              FIN-02015 HUT
   Fax:  +358 9 451 2269              Finland 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=




From Juergen.Haible at nbgm.siemens.de  Fri Jul 10 13:04:23 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 10 Jul 1998 13:04:23 +0200
Subject: AW: question about audio OP amp
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5827FAF3A@nbgm336a.nbgm.siemens.de>


	> Am I mistaken, or do some people claim they can hear the
difference
	> between 741's and other more modern opamps and prefer the sound of
the
	> 741's? I've heard this mentioned before... Any evidence to back
this claim
	> up? 

Never heard of anyone who did a real A/B comparison and said
he liked the 741 better, so this is most probably just a myth.

I write this because I might have contributed to this confusion myself
when I wrote about my SEM filter clone. I deliberately left the 741's 
in there. My argument was it doesn't hurt in the original (no one 
denys that the SEM sound excellent), and *maybe* (stress on 
"maybe" ! ) the 741's (as well as other components') limitations
are part of the overall sound.

The point is that you can not decide whether this is the case or not
by simply exchanging the existing opamps with faster ones. If
you replace the opamps, you also change the delay of a closed loop,
so the original compensation capacitors won't be optimal anymore.
(Not speaking about one opamp's compensation, but of the whole loop,
variation of Q at several cutoff frequencies etc.)

So my suggestion is: Don't touch 741s for new developments. 
If you clone something that has 741s try them first, then try TL071 or
anything similar, and keep what sounds better to your ears. Just
don't try to deduct any general statements about some 
"741 benefits" then (;->).

JH.





From pfperry at melbpc.org.au  Fri Jul 10 16:24:35 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 11 Jul 1998 00:24:35 +1000 (EST)
Subject: AW: question about audio OP amp
Message-ID: <1.5.4.16.19961202070019.443f2480@popa.melbpc.org.au>

At 01:04 PM 10/07/98 +0200, JH wrote:

>Never heard of anyone who did a real A/B comparison and said
>he liked the 741 better, so this is most probably just a myth.
>
There is endless discussion on the ampage guitar fx diy bulletin board
about different sounding chips in fuzz units (these are the same # chip, 
different manufacturers and dates). I don't doubt there ARE differences 
when chips are used 'out of design range'.
And I've seen ckts that depended on the relatively slow slew rate of 741s 
to work.. but I don't think this is one of them.

paul perry melbourne australia




From planet4 at swipnet.se  Fri Jul 10 16:49:42 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Fri, 10 Jul 1998 16:49:42 +0200
Subject: ripple noise...
Message-ID: <35A62A06.54E7F18F@swipnet.se>

Thanks for all the answers on the audio OP amps! There's still something
about my Fatman that bothers me, though...
There is a terrible 50Hz  noise on the audio output due to the
transformer I built into the box. I've tried to screen it etc, but this
is not really my area.
Any ideas would be appreciated! Maybe I have to move the transformer out
of the Fatman box.

Johan





From chordman at flash.net  Fri Jul 10 17:08:11 1998
From: chordman at flash.net (chordman at flash.net)
Date: Fri, 10 Jul 1998 17:08:11 +0200 (MET DST)
Subject: Chaotic Oscillators (over-blown flutes etc)
Message-ID: <199807101508.RAA22989@mailhost.bpa.nl>


This reminds me of a TV program I saw on PBS a number 
of years ago.  Bear with me, there is DIY in this.  
The program was about how and why heart attacks occur.  
The researchers used an analog computer to simulate
a bad heart using chaos theory.  Some adjustable 
parameter controlled the simulation of a blocked 
heart muscle blood vessel and they showed with their 
simulation, which worked like an oscillator, that at 
a certain point, this parameter's value caused the 
system to go more and more chaotic.  Eventually the
oscillation broke down completely.

They never showed the circuit, but did 
show the analogue computer and the setup was not much 
more than 4 or 5 opamps (maybe less, it's been years 
and this is all from memory) and a handful of caps 
and resistors.

It seems to me that an analog computer could be used 
to simulate the natural aspects of a reed, flute or 
brass instrument.  Is anyone brave enough to help 
with the math on this?  I find this very intriguing, 
especially since analog computer components by and 
large are rather inexpensive.  I would love to have 
a VCO with a few 'Chaos' knobs.

-- Scott Gravenhorst
-- FatMan Site: http://www.teklab.com/~chordman
-- RedWebMail by <R<edStarWare





From scott.bernardi at fritz.com  Fri Jul 10 18:15:28 1998
From: scott.bernardi at fritz.com (Scott Bernardi)
Date: Fri, 10 Jul 1998 09:15:28 -0700
Subject: AW: question about audio OP amp
In-Reply-To: <1.5.4.16.19961202070019.443f2480@popa.melbpc.org.au>
Message-ID: <3.0.1.32.19980710091528.009c4210@uxsfo4.fritz.com>

I've seen the same discussion about the opamps used in distortion devices;
specifically, the opamps used in the Ibanez Tube Screamer. Apparently when
originally designed, they used 4558 dual opamps because they were cheap. In
later years, the 4558 became obsolete and the newer units with 1448's
sounded "trashy" - hence an increased market for vintage Tube Screamers.
The Tube Screamer, and in fact many distortion boxes, uses diodes in the
feedback loop of the opamp to clip the signal and cause distortion. There
is some speculation that it is the way an opamp recovers from severe
clipping that has an effect on the sound.
I built a Tube Screamer clone using TL072's, and it sounds pretty good to
me. 'Course i haven't done an A-B comparison.


At 12:24 AM 7/11/98 +1000, you wrote:
>At 01:04 PM 10/07/98 +0200, JH wrote:
>
>>Never heard of anyone who did a real A/B comparison and said
>>he liked the 741 better, so this is most probably just a myth.
>>
>There is endless discussion on the ampage guitar fx diy bulletin board
>about different sounding chips in fuzz units (these are the same # chip, 
>different manufacturers and dates). I don't doubt there ARE differences 
>when chips are used 'out of design range'.
>And I've seen ckts that depended on the relatively slow slew rate of 741s 
>to work.. but I don't think this is one of them.
>
>paul perry melbourne australia
>
>
>
--------------------------------------
Scott Bernardi
voice: 415-538-0439 
fax:   415-904-8375
scott.bernardi at fritz.com



From ebarbour at svetlana.com  Fri Jul 10 18:30:06 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Fri, 10 Jul 1998 09:30:06 -0700
Subject: capacitor voltage ratings
Message-ID: <01BDABE5.53F88BA0.ebarbour@svetlana.com>

>Hi Eric.
>While I'm thinking of it, what voltage should the capacitors be in the
>bandpass. A number of them you haven't specified. Looking at the circuit, I
>figure some (those in the twin T) need to be as high as the power rail (ie
>150v) while others such as the 1 uf on the Q pot can be considerably lower.  
>Cheers.
>Ken


Believe it or not, all of the film capacitors can be rated 100 volts. I've been using
cheap surplus 100v caps in my prototypes, and even though the DC plate supply can
be 150v, the caps NEVER fail. This is because film caps tend to have very
generous underrating, unlike electrolytics. 50% or more underrating is typical at such
low voltages. (Yes, even the coupling capacitor on the plate can be only 100v.
Bear in mind that the idling plate voltage of the small pentode in the VCF or VCA
circuit is only about 40 volts.)

Now, if you were running 400v or more, then you'd have to be more careful about
capacitor voltage ratings........




From tomg at vivid.net  Fri Jul 10 18:34:19 1998
From: tomg at vivid.net (tomg)
Date: Fri, 10 Jul 1998 11:34:19 -0500
Subject: AW: question about audio OP amp
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5827FAF3A@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7495.996.119161072@mail.vivid.net>


>> Am I mistaken, or do some people claim they can hear the
>difference
>> between 741's and other more modern opamps and prefer the sound of
>the
>> 741's? I've heard this mentioned before... Any evidence to back
>this claim
>> up? 

>Never heard of anyone who did a real A/B comparison and said
>he liked the 741 better, so this is most probably just a myth.

Well you have now... IMO the 741 just sounds better for some things like ramp
to pulse converters. The TLO7X/LF3XX series sound very smooth and higher slew
rate devices have a more overdriven sound. A 741 is just right when I need low
slew and noise...:)

-Tom
  




From ebarbour at svetlana.com  Fri Jul 10 18:52:25 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Fri, 10 Jul 1998 09:52:25 -0700
Subject: tube nonlinearity
Message-ID: <01BDABE8.720F2740.ebarbour@svetlana.com>


>>I am under the impression that the "tube sound" is in part
>>caused by their nonlinearity.
>>I guess I am wrong or confused or both :-)

No, the situation is far more complex than that. The problem is with
the poor quality of engineering talent nowadays, and with ignorant
statements made by marketing people.

See the upcoming August issue of IEEE SPECTRUM
magazine for more information.

>hope the book idea regarding tubes
>(as noted on the Engineering Musician site)
>happens, I could use it.

There are a few books on the subject already. Let me recommend:

THE ULTIMATE TONE vols. 1 and 2 by Kevin O"Connor (guitar-amp and preamp design)
PRINCIPLES OF POWER by Kevin O'Connor (guitar-amp and high-end audio)
BEGINNER'S GUIDE TO TUBE AUDIO DESIGN by Bruce Rozenblit (high-end design)

All these books are available from Antique Electronic Supply
at (602) 820-5411 or via their website http://www.tubesandmore.com.


> In fact, some small-signal triodes are MORE LINEAR THAN ANY
> AVAILABLE TRANSISTOR.
> The tubes used in these VCOs are nonlinear, which makes them
> useful for unique FM behavior. A low-distortion tube VCO IS possible.......

>>so the nonlinear nature is in the type of tube, but not tubes in general.
>>That is, one can design for degrees of non linearity?

Yes. There is a VAST range of distortion products possible with tubes;
from extremely low (as in the case of triodes such as antique types
27, 56 and 76, and the later 6CG7, 12BH7 and 12SX7), to the very high
(as in "remote-cutoff" tubes such as the 6SK7 pentode). Take your pick.

And bear in mind, I haven't said ANYTHING
about using negative feedback yet...all this
is achieved WITHOUT feedback......






From terrymbowman at rica.net  Fri Jul 10 19:09:40 1998
From: terrymbowman at rica.net (KA4HJH)
Date: Fri, 10 Jul 1998 13:09:40 -0400
Subject: Chaotic Oscillators (over-blown flutes etc)
In-Reply-To: <199807101508.RAA22989@mailhost.bpa.nl>
Message-ID: <v04011700b1cbfb067328@[208.1.108.122]>

>They never showed the circuit, but did
>show the analogue computer and the setup was not much
>more than 4 or 5 opamps (maybe less, it's been years
>and this is all from memory) and a handful of caps
>and resistors.

I remember that one. They had a Lorenz attractor hooked to an X-Y scope.
Looked idiotically simple.
Terry Bowman, KA4HJH
"The Mac Doctor"



From mthv at dlc.fi  Fri Jul 10 20:37:10 1998
From: mthv at dlc.fi (Tatu Valli)
Date: Fri, 10 Jul 1998 21:37:10 +0300
Subject: CV-VCAs
Message-ID: <35A65F56.9C075177@dlc.fi>

I was thinking to put VCAs in my Modular under
construction, that can control Envelope/LFO/etc..
amount fed to VCF/VCA/etc... 

So the question is: can this be done with any VCA? 

Sory for a dumbass (??) question. 
I am just a stupid newbie.
 
....Tatu...Valli.. at ..Helsinki..Finland.....
...Mails-n-flames:....mailto:mthv at dlc.fi...
...Web:..http://www.dlc.fi/~mthv/zener/....



From cyborg0 at GlobalEyes.net  Sat Jul 11 00:42:27 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Fri, 10 Jul 1998 17:42:27 -0500
Subject: AW: question about audio OP amp
References: <yam7495.996.119161072@mail.vivid.net>
Message-ID: <35A698D3.74CC9B2B@globaleyes.net>

tomg wrote:
> 
> >> Am I mistaken, or do some people claim they can hear the
> >difference
> >> between 741's and other more modern opamps and prefer the sound of
> >the
> >> 741's? I've heard this mentioned before... Any evidence to back
> >this claim
> >> up?
> 
> >Never heard of anyone who did a real A/B comparison and said
> >he liked the 741 better, so this is most probably just a myth.
> 
> Well you have now... IMO the 741 just sounds better for some things like ramp
> to pulse converters. The TLO7X/LF3XX series sound very smooth and higher slew
> rate devices have a more overdriven sound. A 741 is just right when I need low
> slew and noise...:)

	I second this.. I think the frequency response in a 741 vs. a TLXXX is
sonically apparent when you listen to a frequency sweep.. The
disadvantage of a TLxxx is that is seems to impart a slight amount of
gain in the upper frequencies which sounds unnatural, probably cause
most of us have become accustomed to the 741s/discrete trannies tendency
to round off high frequencies.. I think that perhaps the 741 response is
a little more musical.. 
	I have reason to believe that perhaps this is why my Syntecno TeeBee
sounds a little *off* in a high filter resonance, and Im not the only
one who has noticed this, many reviewers and owners have the same
comment
	..It seems to just go TOO high, until most types of distortion (mixer
gain, Sovtek big muff, se-50) are unable to impart added harmonics...
	The ONLY thing in the audio circuitry of the Syntecno TeeBee that has
been reasonably changed is the op-amps from simple low power op-amps to
TLxxx series.. I actually think that the loss of low end and the
overbearing highs are caused by this substitution! 
	Since all the ICs are socketed, Im going to order a handful of low
power 741s and see if Im correct :))
	
Rob Brzykcy



From costello at seanet.com  Sat Jul 11 04:28:08 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 10 Jul 1998 19:28:08 -0700
Subject: Posister???
References: <199807110056.RAA28924@netcom14.netcom.com>
Message-ID: <35A6CDB8.EF6C6C5D@seanet.com>

Tom Moravansky wrote:
> 
> Has anyone ever heard of a posister?  The Roland JP-8 seems to
> use them to help control oscillator pitch.  I need one.  The
> part number in the service manual is  TSP 102J  (1K).  I checked
> on-line and in the Newark/Farnell catalog and no luck so far.
> 
> If I can't fix this oscillator, I'm going to part out the JP-8, so
> if anyone wants/needs replacement parts, let me know and it might
> help make the decision easier.

I know that there is a part called a "posistor" in the TB-303 (I'm not
really a big 303 nut, but I have had a huge schematic of the thing
hanging behind my computer at work for decoration for the past few
years).  It is in the same place as a tempco resistor would be.  My
guess is that it is some sort of temperature compensating resistor (a
resistor in which the resistance varies with temperature, used to
compensate for the temperature sensistivity of semiconductor junctions),
although it may not have the same type of temperature behavior as the
tempcos found in ARPs, Moogs et al.  

I have posted this to the bright kids on synth-DIY, so hopefully a real
answer will be coming soon.

Anyway, don't sell the Jupiter-8.  I know that there are companies that
still make temperature compensating resistors out there.

Sean Costello



From pfperry at melbpc.org.au  Sat Jul 11 04:30:53 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 11 Jul 1998 12:30:53 +1000 (EST)
Subject: ripple noise...in PAiA Fatperson
Message-ID: <1.5.4.16.19961202190636.3777df68@popa.melbpc.org.au>

At 04:49 PM 10/07/98 +0200, Johan Persson  wrote:
>Thanks for all the answers on the audio OP amps! There's still something
>about my Fatman that bothers me, though...
>There is a terrible 50Hz  noise on the audio output due to the
>transformer I built into the box. I've tried to screen it etc, but 

before you conclude it is magnetically radiated hum, try removing the 
transformer physically and run the transformer output to the box by 5 feet
or so of heavy guage wire.. if it STILL hums, as I think it will, then there
is a 
power supply problem.. PAiA have a very competent person answering tech probs,
you could do worse than ask them by phone.

paul perry melbourne australia
...oh, just saw you are in .se!
do you have an oscilloscope?
because you could look at the power rail and see if there was ac there, and
if so 
what shape, which would be a good clue.
Could also be an earthing problem, like a bad connection to aluminium.
good luck and lets know how you get on.




From random at montrealnet.net  Sat Jul 11 06:17:50 1998
From: random at montrealnet.net (Justin Case)
Date: Sat, 11 Jul 1998 00:17:50 -0400
Subject: ripple noise...
Message-ID: <35A6E76E.7964916C@montrealnet.net>

Hi!

Okay, this is my first time ever posting on a mailing list. Hope im
doing everything right. HEah :)

>Thanks for all the answers on the audio OP amps! There's still
something
>about my Fatman that bothers me, though...
>There is a terrible 50Hz  noise on the audio output due to the
>transformer I built into the box. I've tried to screen it etc, but this

>is not really my area.
>Any ideas would be appreciated! Maybe I have to move the transformer
out
>of the Fatman box.

This could (from my dont-have-a-clue point of view) either be
intereference or too much voltage from the transformer. To find out if
it interference, try replacing most wires with shieled ones where
possible and moving the transformer as far as humanly possible. If the
noise persists, you probably don't have the right voltage, too much or
too little voltage often causes noise like that. And if I remember
right, I think PAiA stuff require bi-polarized transformer. I don't have
a clue what's the difference between a normal one and a bi-pol. But Im
pretty sure that could also be causing problems.

Now, I can't see how this would help you, Im far from being good in
electronics, i merely look at specs and follow instruction most of the
time. But, I hope it helps.

Btw, is the fatman a good investement? I've been thinking about buying
one lately. I just didn't enough ressources on how it feels/play.

Jimmy





From sky36919 at skynet.be  Sat Jul 11 08:01:33 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Sat, 11 Jul 1998 08:01:33 +0200
Subject: Chaotic Oscillators (over-blown flutes etc)
In-Reply-To: <199807101508.RAA22989@mailhost.bpa.nl>
Message-ID: <199807111520.RAA25735@papagena.skynet.be>

Hi Scott and List !

On 19jan98 Anders Sponton posted to this list about a diy article 
series from the late 70s UK mag Practical Electronics on analog 
computers .  I have the zip he sent on my computer .  Could 
forward it to you .  It's 1.9mb, so be sure your email can take it :)
A few weeks ago i stumbled upon a book (which i bought :) that was 
mentioned in the jan98 thread : 

ELECTRONIC ANALOG COMPUTERS (D-c Analog computers) (sic)

by Korn and Korn 

second edition

McGraw Hill 1956 

Library of congress 56-8176

No isbn :)

This is all Tubes, and servo motors, and weird multitap pots, and 
flight-simulators, etc ... and has lots of math .  There might be a 
later edition (anyone ?) with semiconductors .

Hope this helps .

Keep 'em oscillating (chaotically ;-)

Hugo
=



From tpaddock at seanet.com  Sat Jul 11 09:07:01 1998
From: tpaddock at seanet.com (Toby Paddock)
Date: Sat, 11 Jul 1998 00:07:01 -0700
Subject: FW: Chaotic Oscillators (Lorenz)
Message-ID: <01BDAC74.C5873C00@d8.dialup.seanet.com>


>>They never showed the circuit, but did
>>show the analogue computer and the setup was not much
>>more than 4 or 5 opamps (maybe less, it's been years
>>and this is all from memory) and a handful of caps
>>and resistors.

KA4HJH[SMTP:terrymbowman at rica.net], July 10, 1998:
>I remember that one. They had a Lorenz attractor hooked to an X-Y scope.
>Looked idiotically simple.
>Terry Bowman, KA4HJH
>"The Mac Doctor"

That sounds like:

Strange New Science of Chaos (The)
NOVA explains "chaos," a new science that is making surprising sense out of chaotic phenomena in nature, from the weather to brain waves.
Original broadcast date: 01/31/89 

I loved that show, was it really that long ago?
I had a real urge to do the circuit.
Found the Lorenz equations and did a basic program (simple).
The question I had (still have) is:

The digital version is not continuous, you do the calculations, THEN feedback, and do it again.
Would you need to do the same in an analog ckt, like with some S/H?  I am guessing not.
But it seems like you would need something to limit the speed of the feedback loops.
Real slow and it might make a nice 3-phase LFO.
I would like to see a simple circuit.  

Hoping this finds you,
Toby Paddock
- -- -  - -- -  - -- -  - -- -  - -- -
http://www.seanet.com/~tpaddock
Pronteon Approved, mostly harmless




From chris.crosskey at metrics.co.uk  Mon Jul 13 15:14:45 1998
From: chris.crosskey at metrics.co.uk (Chris Crosskey)
Date: Mon, 13 Jul 1998 14:14:45 +0100
Subject: OT, but anyway........
Message-ID: <c=GB%a=_%p=Oxford_Metrics_L%l=FILESERV-980713131445Z-1790@fileserv.metrics.co.uk>

Hi guys....
Before I go spamming this round MM and AH, does anyone have a manual for
the Korg SDD-2000 MIDI-controlled digital delay. I've just got one
(swapped for a guitar pedal and a truly horrible old 12-channel Roost
mixer-argh 741's in the audio path <g>) but no manual. Having had an
extended fiddle with it I'm getting no-where fast so will have to
swallow my engineering pride and actually RTFM.......:-(( I need to get
my hands on the manuals to work out how how to control it via MIDI and
also how to program it properly. Also does anyone know if it is a true
stero unit or wether it sums and then splits? I've seen over 4 seconds
quoted for a single delay, which at 12-bit would indicate a sum and
split technique, but it might just have been one mode to boost the
longest quoted delay time out.....I guess the best method would be if
anyones scanned a copy up onto a site and can give me a  pointer, though
I had a big search with several search engines last night and couldn't
find anything.....

chrisc



From pfperry at melbpc.org.au  Mon Jul 13 15:28:30 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 13 Jul 1998 23:28:30 +1000 (EST)
Subject: Kit Lovers take note
Message-ID: <1.5.4.16.19961205060430.39772278@popa.melbpc.org.au>

At 12:16 AM 24/06/98 -0400, bruce duncan  wrote:

>Anyone looking to add an LFO to there diy systems please visit
>http://www.interlog.com/~brucejd/PolyLFO.html
>What seperates this LFO from the pack is the adjustable waveform startpoint
>control.
>
Can anyone say, would it be true that this feature could be added to most
vcos by having a low impedance voltage fed to the frequency determining
capacitor to 
force it to stay at a fixed value? disconnecting the voltage would then let
the osc 
start off from where it was forced to.




From thudson at cygnus.com  Mon Jul 13 15:50:48 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Mon, 13 Jul 1998 09:50:48 -0400
Subject: envelope generators
References: <199807120550.NAA22486@defiant.git.com.au>
Message-ID: <35AA10B8.9E6A2484@cygnus.com>

You may want to look at the CEM 3371 datasheet:
http://www.synthtech.com/cem/c3371pdf.pdf

I haven't played with this chip (yet) but it looks like
it could be used to do any number of stages. 

Thomas


geoffery francis james wrote:
> 
> does anyone on this list know of a cct for an EG that has more than the
> usual four stages(say 8,10,or 12) with the ability to place the sustain
> portion in different sections of the envelope as well as have a delay
> section for stage 1?
> thanks in advance
> geoff james



From debus at cww.de  Mon Jul 13 16:55:17 1998
From: debus at cww.de (Ingo Debus)
Date: Mon, 13 Jul 1998 16:55:17 +0200
Subject: envelope generators
References: <199807120550.NAA22486@defiant.git.com.au>
Message-ID: <35AA1FD4.4F16@cww.de>

geoffery francis james wrote:
> 
> does anyone on this list know of a cct for an EG that has more than the
> usual four stages(say 8,10,or 12) with the ability to place the sustain
> portion in different sections of the envelope as well as have a delay
> section for stage 1?

CEM 3371?

Ingo




From b.layer at vikingelectronics.com  Mon Jul 13 18:36:51 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 13 Jul 1998 11:36:51 -0500
Subject: 3-throw switches, octavation & tubesynth
Message-ID: <3.0.5.32.19980713113651.007bf220@192.168.210.18>

Hi All,

This reply was prompted by an earlier posting re: "3-throw" switches, but
has application specific to the EB tubesynth VCO.

One 'common' form of the 3-throw switch is the old-fashioned 'DP projector'
style which has the following states:

	1) Down - Off
	2) Mid - circuit 1 on
	3) Up - circuits 1 and 2 on

In a VCO that is frequency dependent on a simple R-C time constant (read:
EB's thyratron VCO) this type of switch used in conjunction with 3 matched
capacitors can be used to provide a very neat 3-octave (low-med-hi) range
switch, by using the seperate circuits to switch a series-parallel cap bank.

The accuracy of the octavation is depenent entirely on the accuracy of the
cap matching, which can be very good. Obviously, low-dissipation
factors/leakage are very helpful. I can provide a simple schematic for
anyone interested.

A note on matching small value caps: DO NOT handle them prior to or during
the matching process, if at all possible. Minute temp changes from your
body will play havoc with the readings, make for a poor match, and waste
huge amounts of your time.

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From ebarbour at svetlana.com  Mon Jul 13 19:38:13 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Mon, 13 Jul 1998 10:38:13 -0700
Subject: tubes, transistors......
Message-ID: <01BDAE4A.57AE5E20.ebarbour@svetlana.com>

>Saying that tubes are non-linear to some degree (as he did) is not
>much of a fallacy, but you are also right in that you may get a
>wonderfully linear response from them as well.

Sorry if you were annoyed by my comments, Magnus. The main issue
here is that I constantly hear these incorrect statements about tubes,
repeated over and over again. Their 3/2-power response is not the
problem--the problem is with the actual signal distortion in-circuit,
using a standard class-A amplifier circuit. Load-lines do not follow
the 3/2 curves, and it's the load line that determines the input-output
voltage gain equation of a device. (Nor does the load line of a bipolar
transistor follow an exponential response. The SPACING of the device
curves determines its linearity.)

Even an average 6SN7 triode can beat the PANTS off any transistor
operating at typical low voltages, in a simple distortion test.
As we at VACUUM TUBE VALLEY magazine discovered.

The guy who made the original comment was just repeating something
he read. It's not his fault.

Often I find myself answering these comments. They are
made very often, by electrical engineers and marketing gurus
who think they know why these "crazy audiophiles" prefer tubes.
They always miss the point!
Distortion spectra are only PART of the reason for using tubes,
and only then as a sound effect. Too many smart people like
to make ignorant generalizations, which are then repeated by
ordinary people as if they were hard facts. That's what happened here.

I am NOT trying to start flames. So everyone, please calm down.

> EB> 	I CAN PROVE IT!!! Any takers? 
>Eric, I did NOT see those lines, do you know why?

The information was not posted here, because it will shortly
appear in IEEE SPECTRUM magazine........that ought to be
authoritative enough to be taken more seriously than stuff like
this, off the PAIA website, written by John Simonton:

>One by one these squashing characteristics have been removed.
>The first improvement was transistors. It's difficult and expensive to make tube
>circuitry linear, they just really don't want to do it. Individual transistors
>are no more linear than tubes, but they're cheap so you can afford to use
>lots of them..................................When loafing along within their design
>envelopes, there is no discernible difference between SS and VT amplifiers.
>This has been shown again and again in well designed double blind tests. 

The whole text is at http://www.paia.com/tubesnd.htm.

As much respect as I have for John Simonton, I feel compelled to point out
that he is WRONG here. There are other sonic effects inherent in solid-state
electronics--voltage-variable capacitances, slew-rate limiting, high negative
feedback and its effects, etc. These effects are TRANSIENT,
and do not show up in static distortion tests, nor do they become very apparent
in some A-B listening tests.
These transient effects are nonexistent or less apparent in tubes.

"It's difficult and expensive to make tube circuitry linear, they just really don't want to do it."
Sorry, John, you have a LOT to learn. It's not as simple as that.

And there are a few tube/transistor A-B listening tests in the literature--unfortunately,
they were often biased, because the people running them had an agenda
to accomplish. (One of the most notorious "tests" was run by Dan Dugan in the AES Journal
some years ago--it is still often quoted by the uninformed, even though Dugan was heavily
criticized at the time for not allowing the listeners longer selections, and for being domineering
and aggressive in his methods. Dugan is a notorious "skeptic" who has a blatant
anti-tube bias. It's really funny--I happen to know that he services Nagra equipment
as part of his business; Nagra recently introduced a very expensive TUBE amplifier
and preamp......... )

A major objection to these tests, by respected academics such as
Dr. James Boyk at Caltech, is that such tests allow only a few seconds
of listening for each device, rather than allowing the listeners to control the
musical material and length. This has only made the tube-using
audiophiles bolder, and roiled the waters further.

Let's put an end to this thread, it has very little to do with synths anyway.
I'll end with a suggestion for any interested parties to read the SPECTRUM article.
It is scheduled to appear in the upcoming August 1998 issue.






From synth1 at airmail.net  Mon Jul 13 20:09:44 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Mon, 13 Jul 1998 18:09:44 -0000
Subject: Still in limp mode.
Message-ID: <01BDAE8A.C291D920@dal38-28.ppp.iadfw.net>

For those of you wondering if I disappeared off the planet:
I am just now starting to unpack the 43 boxes that used to be
my lab/studio. I hope to be back up and running this weekend.
Sorry it is taking so long, the 112F degree day yesterday didn't
help the 'let's clear out the attic' party.

Also, the MOTM-400 Moog filter/preamp/envelope follower
module is still in the breadboard stage. I am in the process
of changing sheet metal companies, and the quotes I have
received so far are about 20% higher than before. This means 
newer kits will be about $5-7 more than planned. No so bad :)
Street date around Aug. 23rd.

Again, sorry if your email is 'ignored' for a few more days:
I'll be back on-line soon.

2 DIY'ers have already cut new tracks with the MOTM
modules for release! I'll keep you posted when they hit the streets.

The last word I received about CharlieT (about 10 days ago)
is not good. The chemo caused abnormal swelling in his neck. They
sent him to hospice care. I will passs more info as I get it.

Paul Schreiber
Synthesis Technology




From MiScherr at aol.com  Mon Jul 13 20:52:41 1998
From: MiScherr at aol.com (MiScherr at aol.com)
Date: Mon, 13 Jul 1998 14:52:41 EDT
Subject: SH101 Bender unit
Message-ID: <be0b1795.35aa577a@aol.com>

Is there anybody, who can tell me, how the bender-unit in the SH101 works?
Are there two potentiometers (one x-axis, one y-axis), which are connected
together?



From magnus at analogue.org  Mon Jul 13 22:50:09 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 13 Jul 1998 22:50:09 +0200
Subject: tubes, transistors......
In-Reply-To: Your message of "Mon, 13 Jul 1998 10:38:13 -0700"
References: <01BDAE4A.57AE5E20.ebarbour@svetlana.com>
Message-ID: <199807132048.WAA05676@piraya.electrum.kth.se>

>>>>> "EB" == Eric Barbour <ebarbour at svetlana.com> writes:

Hi Eric and all you others!

 >> Saying that tubes are non-linear to some degree (as he did) is not
 >> much of a fallacy, but you are also right in that you may get a
 >> wonderfully linear response from them as well.

 EB> Sorry if you were annoyed by my comments, Magnus. The main issue
 EB> here is that I constantly hear these incorrect statements about tubes,
 EB> repeated over and over again.

Let me stress that I was only annoyed about the more flamish or
flamish-like parts. I certainly don't mind you making a point about
that tubes are good, and can you prove it then the better.

 EB> Their 3/2-power response is not the
 EB> problem--the problem is with the actual signal distortion in-circuit,
 EB> using a standard class-A amplifier circuit. Load-lines do not follow
 EB> the 3/2 curves, and it's the load line that determines the input-output
 EB> voltage gain equation of a device. (Nor does the load line of a bipolar
 EB> transistor follow an exponential response. The SPACING of the device
 EB> curves determines its linearity.)

Well, I must confes that I haven't spent too much time study up on the
subject, but I do have spent some time and will continue to do so.

The 3/2 curve is the transconductance behavior just as the exponential
curve for bipolars are.

 EB> Even an average 6SN7 triode can beat the PANTS off any transistor
 EB> operating at typical low voltages, in a simple distortion test.
 EB> As we at VACUUM TUBE VALLEY magazine discovered.

 EB> The guy who made the original comment was just repeating something
 EB> he read. It's not his fault.

 EB> Often I find myself answering these comments. They are
 EB> made very often, by electrical engineers and marketing gurus
 EB> who think they know why these "crazy audiophiles" prefer tubes.
 EB> They always miss the point!

I think I understand this point you are making, but then I find that
this category mostly misses the point so... It is certainly an most
anoying thing. Some of the tube-heads that I have met have how ever
also missed the point or at least been babeling about so much rubbish
that listening to it all just became anoying. This is BTW true for
many non-tube people too. If you happend to find my 1st of April fool
from last year (on AH) I think you can get my feeling about it.
But I think that the kind of people hanging around on this list falls
into a diffrent category and thus could be treated in a diffrent way.

 EB> Distortion spectra are only PART of the reason for using tubes,
 EB> and only then as a sound effect. Too many smart people like
 EB> to make ignorant generalizations, which are then repeated by
 EB> ordinary people as if they were hard facts. That's what happened here.

This problem one has to fight every day. What MAY be true in one
special case migth not be true in another not to say a general
case. Hell, it might not be true in the special case it is being said
to hold for. Today I found that yeat another generalisation that a few
of my companies EEs made did not hold, so tomorrow we will fix it
behind their backs in order to save money and time... most anoying.

 EB> I am NOT trying to start flames. So everyone, please calm down.

Well, it seems that (in my eyes) you tended to use formulations
indicating that you more or less been heading this way. I would even
say that I seen strong tendenses, and I don't want to see that.

 EB> I CAN PROVE IT!!! Any takers? 
 >> Eric, I did NOT see those lines, do you know why?

 EB> The information was not posted here, because it will shortly
 EB> appear in IEEE SPECTRUM magazine........that ought to be
 EB> authoritative enough to be taken more seriously than stuff like
 EB> this, off the PAIA website, written by John Simonton:

Eh, I where more refering to that I mentally blinded myself for the
comments you made, in order not to accidentally fall into flamewar mode.
My comment where pointing towards the fact that they where trapish.

 >> One by one these squashing characteristics have been removed.
 >> The first improvement was transistors. It's difficult and expensive to make tube
 >> circuitry linear, they just really don't want to do it. Individual transistors
 >> are no more linear than tubes, but they're cheap so you can afford to use
 >> lots of them..................................When loafing along within their design
 >> envelopes, there is no discernible difference between SS and VT amplifiers.
 >> This has been shown again and again in well designed double blind tests. 

 EB> The whole text is at http://www.paia.com/tubesnd.htm.

 EB> As much respect as I have for John Simonton, I feel compelled to point out
 EB> that he is WRONG here. There are other sonic effects inherent in solid-state
 EB> electronics--voltage-variable capacitances, slew-rate limiting, high negative
 EB> feedback and its effects, etc. These effects are TRANSIENT,
 EB> and do not show up in static distortion tests, nor do they become very apparent
 EB> in some A-B listening tests.
 EB> These transient effects are nonexistent or less apparent in tubes.

It is certainly true that NP-junctions have a voltage-variable effect,
it is a very nonlinear effect. The high negative feedback (I think you
are refering to the Miller effect) is also there. One thing that
people tend to do wrong with bipolars is to use them as both voltage
and current amplifiers in the same time, high-current transistors
should be left away from voltage amplification to perform well. I have
seen power amps built this way work well.

The understanding of transients and their effect is as much black
magic as many other things to many people. When one care about
transient responce (regardless of technique in use) will much better
performance manifest itself than if you just strive for that
ultra-flatt frequency response. This is certainly true for large PAs
as well as a home setup, I have done both.

However, when I see how people go about and destroy their impulse
responses with all kinds of stuff (like most of the speakers out
there) will the empere's new cables or whatever just be a change of an
screwed up behaviour rather than an actual fix.

 EB> "It's difficult and expensive to make tube circuitry linear, they just really don't want to do it."
 EB> Sorry, John, you have a LOT to learn. It's not as simple as that.

 EB> And there are a few tube/transistor A-B listening tests in the literature--unfortunately,
 EB> they were often biased, because the people running them had an agenda
 EB> to accomplish. (One of the most notorious "tests" was run by Dan Dugan in the AES Journal
 EB> some years ago--it is still often quoted by the uninformed, even though Dugan was heavily
 EB> criticized at the time for not allowing the listeners longer selections, and for being domineering
 EB> and aggressive in his methods. Dugan is a notorious "skeptic" who has a blatant
 EB> anti-tube bias. It's really funny--I happen to know that he services Nagra equipment
 EB> as part of his business; Nagra recently introduced a very expensive TUBE amplifier
 EB> and preamp......... )

It is easy to "prove" something, it is far less easy to do it in a
scientifically way such that it will survive the critical eye and
other test. There is also many diffrent sides to things, often one
sees how people tries to show something where they infact showed
something else and through vague bridges (often postulates that can be
found untrue with some minor knowledge) the try to prove some fact.

I will not get into discussion weither Dan Dugan did so or not.

 EB> A major objection to these tests, by respected academics such as
 EB> Dr. James Boyk at Caltech, is that such tests allow only a few seconds
 EB> of listening for each device, rather than allowing the listeners to control the
 EB> musical material and length. This has only made the tube-using
 EB> audiophiles bolder, and roiled the waters further.

 EB> Let's put an end to this thread, it has very little to do with synths anyway.
 EB> I'll end with a suggestion for any interested parties to read the SPECTRUM article.
 EB> It is scheduled to appear in the upcoming August 1998 issue.

This thread is not a nice one, but I think we have touched a few other
subjects which could be enlightening to continue on.

As for the IEEE Spectrum article, at least I will look forward to see it.

Cheers,
Magnus






From gur-m at internet-zahav.net  Mon Jul 13 23:02:02 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Mon, 13 Jul 1998 23:02:02
Subject: MOTM 100 mod's
Message-ID: <3.0.2.16.19980713230202.2ba7a766@mail.internet-zahav.net>

hi guy's.
had any body build the 100 noise/s&h with banana ?
the 1/4" jack's used in the motm are switchable and in
the 100 module they are used to switch betwin the internal
clock and the ext clock when an ext is patched in,so if you use
banana you gut a problem ther.
all so had any body made the internal clock out mod,i
drill the panel for this output but i'm not shure frome
where i need to wire on the pcb,is it the empty hole neer the
555 right above c18 ?

thanx
Gur Milstein




From sky36919 at skynet.be  Tue Jul 14 07:11:41 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Tue, 14 Jul 1998 07:11:41 +0200
Subject: Press_n_Peel laserprinter
Message-ID: <199807140513.HAA17117@papagena.skynet.be>

Hi List !

My first question to this list :)

I just received a pack of PnP Blue from Techniks .

Not having a Laserprinter and wanting to acquire one, i wondered if 
any of you have experience (good or bad :) with the printers that are 
on the market right now .  There used to be a faq on the net, but 
apart from it having disappeared, it was not very recent, so no 
comments on printers available at present :(

The general consensus was that HP machines were good, but i wonder 
about the paper path in the 6L (it being not flat) for ex .

Also type nos of photocopiers that definitely work would be a great 
help .

Thanks for your time .

Keep 'em oscillating :)

Hugo
=



From Juergen.Haible at nbgm.siemens.de  Tue Jul 14 12:13:33 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 14 Jul 1998 12:13:33 +0200
Subject: AW: tubes, transistors......
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58281EFDD@nbgm336a.nbgm.siemens.de>


	>The guy who made the original comment was just repeating something
	>he read. It's not his fault.
	>
	>Often I find myself answering these comments. They are
	>made very often, by electrical engineers and marketing gurus
	>who think they know why these "crazy audiophiles" prefer tubes.
	>They always miss the point!

Tubes and transistors are in competition in (at least) two
very different battle fields. One is HiFi, and the other is
Instrument amplification.

Everything you are writing here about prejudice against
tube amplifiers, and transient vs. static distortion is true,
all too well known, and I won't go into it any further. It's
"HiFi" domain.

When we look at sound generation (instead of sound 
reproduction), everything is different. How many guitarists
have you heard complaining about the distortion of the
tubes in their amp ? There's also a lot arguing if this
sound can be emulated to some degree with solid
state circuits or not, but the point is that the *distorted*
tube sound is the *reference* here, and "tube distortion"
is a compliment, not an insult. 

With building electronic music instruments and FX devices,
I always feel much closer to a guitar amp than to the HiFi
stuff, and I'm sure most people here feel similar.
Any complaint about the distortion of a Moog cascade ?
The distortion of a timbre modulator ?
I think you get the point. So if anybody here mentions "tube
distortion" in a subordinary clause, you can bet he has no
bad intention, and more important, he may be completely
RIGHT in this context.

JH.




From random at montrealnet.net  Tue Jul 14 12:47:57 1998
From: random at montrealnet.net (Justin Case)
Date: Tue, 14 Jul 1998 06:47:57 -0400
Subject: Juno106 High Pass Filter Slider
Message-ID: <35AB375D.D79DAD70@montrealnet.net>

Hi there you synthethic freaks.

Okay, I bought a Juno106 not that long ago. And ehum. It has two broken
sliders. One is a normal run-off-the-mill slider. So it's pretty dumb to
change. But, the other one is the High Pass Filter slider. And it is not
only broken. It's MISSING altogether. And this slider is a 4 position
slider, not a normal slider. My questions are:

Could I install a normal slider instead of replacing it with a 4pos
slider? I mean, would it behave like it's still 4 position? Is it more
like a switch? or IS IT a switch? Because I'd like to have a real slider
on the HPF instead of being limited to 4 cutoff position.

And, if I really have to replace it with a 4pos slider. Anybody knows
what is the model/serial/anything of that specific piece? As I said,
it's missing, so I don't have a clue what the piece really is. And where
could I get one?

I know this looks like a basic stupid question, but Im a basic stupid
newbie too :) I don't have all that much experience and I need help! I
don't wanna send it to the store to have it repaired and get charge
32479$ for the job. I know this is just a 10-30$ job so.

Thanks

Jimmy





From b.layer at vikingelectronics.com  Tue Jul 14 15:42:20 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 14 Jul 1998 08:42:20 -0500
Subject: Thanks for, and question re: EML 300/301 Schemos
Message-ID: <3.0.5.32.19980714084220.007b1870@192.168.210.18>

All,

I received yesterday an envelope containing a set of schematics for an
EML-301; as requested. Now, if the individual who sent this had been so
kind as to give a return address, I could thank them personally!

I think they came from Gino Wong, but there are other possibilities. In any
case, thank whomever VERY MUCH for sending them.

Oddly enough, the circuit giving me trouble in smack dab in the middle of
the diagram, as if someone else had copied it for the same reason/failure...

Burning question: can anyone tell me the dif between an EML-300 and an
EML-301? I find no records of the 301, except for the schemo that I now
have. It is similar to my EML-300, but seems to have a variety of extra
features. Who knows this?  

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From leitner6 at concentric.net  Tue Jul 14 16:22:41 1998
From: leitner6 at concentric.net (Larry Leitner)
Date: Tue, 14 Jul 1998 09:22:41 -0500
Subject: Sid Station
Message-ID: <35AB69AA.DC5DADDA@concentric.net>

This is off topic but the SID chip comes up on the list every now and
then....


Check it out


 http://www.sidstation.com


Larry




From b.layer at vikingelectronics.com  Tue Jul 14 16:33:01 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 14 Jul 1998 09:33:01 -0500
Subject: Message not deliverable
In-Reply-To: <0005190D.CE21411@harpercollins.com>
Message-ID: <3.0.5.32.19980714093301.0079f100@192.168.210.18>

At 10:02 AM 7/14/98 -0400, you wrote:
>All,
>
>I received yesterday an envelope containing a set of schematics for an
>EML-301; as requested. Now, if the individual who sent this had been so
>kind as to give a return address, I could thank them personally!
>
>I think they came from Gino Wong, but there are other possibilities. In any
>case, thank whomever VERY MUCH for sending them.
>
>Oddly enough, the circuit giving me trouble in smack dab in the middle of
>the diagram, as if someone else had copied it for the same reason/failure...
>
>Burning question: can anyone tell me the dif between an EML-300 and an
>EML-301? I find no records of the 301, except for the schemo that I now
>have. It is similar to my EML-300, but seems to have a variety of extra
>features. Who knows this?  
>
>------------------------------
>Bill Layer
>Sales Technician
>
>Viking Electronics, Inc.
>1531 Industrial St.
>Hudson, WI 54016
>
>Phone: (715)386-8861 Ext. 210
>Fax: (715)386-4344
>E-mail: b.layer at vikingelectronics.com
>
>http://www.vikingelectronics.com
>24 Hour Fax Back System: (715)386-4345
>

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From tsheets at saturn5.com  Tue Jul 14 17:56:28 1998
From: tsheets at saturn5.com (Troy Sheets)
Date: Tue, 14 Jul 1998 08:56:28 -0700 (PDT)
Subject: New .mp3 track online...
Message-ID: <199807141556.IAA15575@atari.saturn5.com>



I have a new track, "Biohazard" compressed into .mp3 format and available
for download from my web site:

http://www.saturn5.com/tsheets/audio

It is best described as breakbeat trance.  My ASM-1 is used extensively...
in fact, it is the first synth you hear.  The other synth sounds come
from Waldorf Pulses.

Feedback is always apperciated...

-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 jfoster at lucasdigital.com  Tue Jul 14 18:06:08 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Tue, 14 Jul 1998 09:06:08 -0700
Subject: AW: tubes, transistors......
References: <1BF5E20E0C4DD111BBAB00805FE2D58281EFDD@nbgm336a.nbgm.siemens.de>
Message-ID: <35AB81F0.374C3D09@lucasdigital.com>



Haible Juergen wrote:

> -snip-
>
> When we look at sound generation (instead of sound
> reproduction), everything is different. How many guitarists
> have you heard complaining about the distortion of the
> tubes in their amp ? There's also a lot arguing if this
> sound can be emulated to some degree with solid
> state circuits or not, but the point is that the *distorted*
> tube sound is the *reference* here, and "tube distortion"
> is a compliment, not an insult.
>
> With building electronic music instruments and FX devices,
> I always feel much closer to a guitar amp than to the HiFi
> stuff, and I'm sure most people here feel similar.
> Any complaint about the distortion of a Moog cascade ?
> The distortion of a timbre modulator ?
> I think you get the point. So if anybody here mentions "tube
> distortion" in a subordinary clause, you can bet he has no
> bad intention, and more important, he may be completely
> RIGHT in this context.
>
> JH.

I agree, we are interested in the sound, not the chart recorder output :-)lets
get back to sound and circut design. BTW - some of what I stated early started
this
latest exchange battle, so I say enough and lets enjoy the helpfulness and
knowledge this list brings to
each of us.

soooo, has anyone built EB's tube vco, vcf or vca ??

ta,
Jeff

--
Jeff Foster - 415-662-1254
System/Network Engineer, Skywalkersound, Lucasdigital Ltd.





From pfperry at melbpc.org.au  Tue Jul 14 18:06:22 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 15 Jul 1998 02:06:22 +1000 (EST)
Subject: motorised pots
Message-ID: <1.5.4.16.19961206084212.22d739ca@popa.melbpc.org.au>

anyone using or knowing sources of motorised pots?
I can get some twin 10k ones but 1. they look pretty cheapo and
2. they take 10 seconds to travel around! which makes them useless 
for the effects processor I am designing.
I was hoping to have the pots rotate to the appropriate positions
when a patch is called up from memory. I notice that even the latest 
Yamaha guitar amps have 96 memories and rotating knobs!!!!!

paul perry melb australia




From b.layer at vikingelectronics.com  Tue Jul 14 18:32:41 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 14 Jul 1998 11:32:41 -0500
Subject: AW: tubes, transistors......
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58281EFDD@nbgm336a.nbgm.sieme
 ns.de>
Message-ID: <3.0.5.32.19980714113241.007b3be0@192.168.210.18>

>When we look at sound generation (instead of sound 
>reproduction), everything is different. How many guitarists
>have you heard complaining about the distortion of the
>tubes in their amp ? There's also a lot arguing if this
>sound can be emulated to some degree with solid
>state circuits or not, but the point is that the *distorted*
>tube sound is the *reference* here, and "tube distortion"
>is a compliment, not an insult. 
>
>With building electronic music instruments and FX devices,
>I always feel much closer to a guitar amp than to the HiFi
>stuff, and I'm sure most people here feel similar.
>Any complaint about the distortion of a Moog cascade ?
>The distortion of a timbre modulator ?
>I think you get the point. So if anybody here mentions "tube
>distortion" in a subordinary clause, you can bet he has no
>bad intention, and more important, he may be completely
>RIGHT in this context.
>
>Hi All/Juergen,

You have brought up a VERY interesting point, and one that is not so off
topic as to be beyond discussion in this forum. Please everyone, indulge me
for a few moments.

Juergen's comments have raised a deep and perplexing Zen-type issue, that
is: What is the actual sound of an electronic instrument? The design or the
parts or the patch or???? (and you thought I was going to ask what is the
sound of one bifet clapping!)

A logically related question is: what is the sound of an instrument, if not
the sum of it's fundamental and distortion products, irrespective of the
source of that distortion? How is it defined? How should we define it?

Finally, the most intersting question of all arises: Where does the
instrument begin and end? This is even more puzzling if you consider a
modular system, where the issue is most cloudy. 

Now that I've brought this zen discussion to the table, a bit of my own
un-zenlike dogma. I think that electroinc instruments are being used at
their worst and weakest, when one endeavours to duplicate the sound of a
real accoustic instrument; that is: the original goal of music synthesis
(that of flawless emulation), is just flat pointless and moreover,
tasteless (don't agree? listen to Switched on Brandenburgs or anything by
Tomita EXCEPT for the Englufed Cathedral) for any purposes other than
academic.

I for one would NEVER tolerate transistor artifacts in my stereo PERIOD,
but on the other hand, I think they are fine for Emusic apps, INCLUDING
signal processing. Why this apparent contradiction? Because IMO, there is
nothing inherently 'correct', genuine  or natural about the sound of an
eMusic instrument, but there IS something inherently correct about the
manner in which it is reproduced.

Someone elses's thoughts?


>

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From PapaJ59871 at aol.com  Tue Jul 14 19:40:35 1998
From: PapaJ59871 at aol.com (PapaJ59871 at aol.com)
Date: Tue, 14 Jul 1998 13:40:35 EDT
Subject: tubes, transistors......
Message-ID: <fc9b6989.35ab9814@aol.com>

In a message dated 98-07-13 13:54:28 EDT, ebarbour at svetlana.com writes:

<< Sorry, John, you have a LOT to learn. >>

Sure do, and glad of it. Knowing it all already is obviously a very
frustrating proposition :-)

I guess part of the problem is that I'm sometimes quoted as an "expert" when
in my own mind I'm nothing of the sort. Just another guy exploring the world
and sharing what I find.

-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 b.layer at vikingelectronics.com  Tue Jul 14 20:10:48 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 14 Jul 1998 13:10:48 -0500
Subject: motorised pots
In-Reply-To: <1.5.4.16.19961206084212.22d739ca@popa.melbpc.org.au>
Message-ID: <3.0.5.32.19980714131048.007b2170@192.168.210.18>

At 02:06 AM 7/15/98 +1000, you wrote:
>anyone using or knowing sources of motorised pots?
>I can get some twin 10k ones but 1. they look pretty cheapo and
>2. they take 10 seconds to travel around! which makes them useless 
>for the effects processor I am designing.
>I was hoping to have the pots rotate to the appropriate positions
>when a patch is called up from memory. I notice that even the latest 
>Yamaha guitar amps have 96 memories and rotating knobs!!!!!
>
>paul perry melb australia
>
>Paul,

In a nutshell, yes I do know where you can get this. The story: Back in the
old days, the Atma-Sphere MP-1 preamp used a pair of servo-driven pots to
control DC offset in the output section. Well, to make a long story short,
we developed a much better way to do this, and subsequently, as units came
in for update the motors (high-precision, Swiss big money stuff with cutom
bracket & mounted bourns 10K pot) were all removed and sold to:

AxMan Surplus
St.Paul, MN
612.646.8653

Call and ask for Barb or Am, tell them you want the little Swiss motor
thingy with the black aluminum bracket & blue pot that came from Ralph
and/or Bill at Atma-Sphere. If they can't find it, I probably can. Am will
know who I am.

How's THAT for a direct hit? Your cost should be about $20-25 ea; 1/10th of
what ASMS paid for these things. We're talkin' high precision, here.
Interested?

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From costello at seanet.com  Tue Jul 14 21:40:34 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 14 Jul 1998 12:40:34 -0700
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply?
Message-ID: <35ABB432.4CC0C64B@seanet.com>

Hi everyone:

I want to actually start building some of the circuits I have on my page
(http://www.seanet.com/~costello), but I would like to make a few
changes.  Specifically, I would like to create a diode ladder filter (a
la the VCS3 or TB303) that can be run off of a single ended power supply
(in this case, a 9V battery).  I just like 9V batteries, OK?

Any ideas how I would go about this?  I know the TB-303 uses a single
ended power supply, so I know that it is possible.  The tricky part is
the transistor(s) that convert the filter voltage control into the
exponential current needed for the diode ladder.  I could just copy the
circuitry from the TB-303 (it is pretty darned nifty, with the "gimmick"
for lowering the cutoff frequency while increasing the envelope
modulation), but I would really like to know what I am doing before I
start.  I really don't want to simply clone the 303 filter; I'd like to
adapt the core of the VCS3 filter (check my page for a reasonable clone
of the VCS3 filter), and possibly use germanium diodes for the filter.

Any other issues I would encounter with running the VCS3 filter off of
+9V?  How about the diodes at the "top" of the ladder (i.e. the 3 pairs
above the main R/C diode pairs)?  What do they do?  

Also, could the TB-303 expo stage be used in a Moog ladder filter?  Can
the Moog ladder filter run off of a 9V battery?  The schematics for the
discrete Moog filters (Minimoog, 904a) seem to only use the negative
supply for the exponential convertor.  Can these be converted to run off
of a single ended supply?  Advantages, disadvantages?

Any advice welcome (answers, directions of where to look for answers,
etc.). 

I'm also interested in creating an MS-20 filter section clone that is
battery operated (I LOVE battery operated boxes - my little x0x boxes
are getting a lot of use nowadays, while I wait for the NM to arrive).
Any advice there?  It seems more straightforward - just using a voltage
divider to create a "virtual ground" that is 1/2 of the positive supply.
Any other tricks?

Thanks,

Sean Costello (who realizes how this post totally gives away his
ignorance of all things electronic.  I was reading "The Art of
Electronics" last night, and learned way too much that I should have
known before.  Apologies in advance for my ignorance, but I really do
want to learn this stuff.)



From gosd at lankaster.com  Tue Jul 14 22:21:22 1998
From: gosd at lankaster.com (Deborah & Crystal)
Date: Tue, 14 Jul 1998 13:21:22 -0700
Subject: top octave chip
Message-ID: <35ABBDC1.2CC6@lankaster.com>

hi my name is Crystal and i've been lurking hereabouts for a while. i've
found a lot of useful info and ideas. thanx all
 
i'm writing the list to see if anyone has a 50240 top octave synth chip
they would like to trade or sell me. or if there's any source out there
that has some for sale. thanx again



From gosd at lankaster.com  Tue Jul 14 22:31:14 1998
From: gosd at lankaster.com (Deborah & Crystal)
Date: Tue, 14 Jul 1998 13:31:14 -0700
Subject: "alternative controllers"
Message-ID: <35ABC011.104C@lankaster.com>

hi again synth friends,
i've been following the discussions on ldr's and finding it very
interesting. i've just built a light controller board which i call the
flying saucer because of it's shape. it has 6 CdS cells ( so far ) in
the shape of a butterfly like this:
                    x                             x
                         x                   x
                       x                       x
it's one of my favorite controllers i have built so far. i'd like to
discuss these and other kinds of controllers (lately i've been very
interested in ribbon controllers) with anyone interested.happy
synthesizing y'all



From fa at fa.camelot.de  Tue Jul 14 22:48:00 1998
From: fa at fa.camelot.de (Florian Anwander)
Date: 14 Jul 1998 22:48:00 +0200
Subject: Juno106 High Pass Filter Slider
In-Reply-To: <35AB375D.D79DAD70@montrealnet.net>
Message-ID: <6xs0pTO4OZB@fa.camelot.de>

Hello Justin

>And where could I get one?
It should be quite simple (or should I say: in Germany it is quite simple and  
it should work in Canada similar): just call Roland Canada and Order this  
specific spare part. It might cost about $2 or $3 plus postage.



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 lev at onthenet.com.au  Tue Jul 14 22:56:56 1998
From: lev at onthenet.com.au (lev)
Date: Tue, 14 Jul 1998 20:56:56 +0000
Subject: SH101 Bender unit
References: <be0b1795.35aa577a@aol.com>
Message-ID: <35ABC617.52B@onthenet.com.au>

1 pot for the bender and a momentary switch if you push it forward (for
the modulation).  

Enjoy.


Lev =)




MiScherr at aol.com wrote:
> 
> Is there anybody, who can tell me, how the bender-unit in the SH101 works?
> Are there two potentiometers (one x-axis, one y-axis), which are connected
> together?



From martink at cix.compulink.co.uk  Tue Jul 14 21:05:00 1998
From: martink at cix.compulink.co.uk (Martin Keefe)
Date: Tue, 14 Jul 98 21:05 BST-1
Subject: AW: tubes, transistors......
Message-ID: <memo.567815@cix.compulink.co.uk>


Hello all,

I've just joined this list so please forgive me if I repeat something that 
already been said.

While I'm sure that most analogue synths have their individual charms from 
the *user's* point of view, if I were *designing* one I would be striving 
for neutrality at every stage. If the synth user wants a tube sound it 
should be possible to combine and program modules to mimic it. It could 
even be available as some sort of preset although exactly what a tube 
sound is probably varies with context.

  ]\/[artin




From martink at cix.compulink.co.uk  Tue Jul 14 21:05:00 1998
From: martink at cix.compulink.co.uk (Martin Keefe)
Date: Tue, 14 Jul 98 21:05 BST-1
Subject: DSP anybody?
Message-ID: <memo.567817@cix.compulink.co.uk>


Is anybody on this list looking at using DSPs to create "analogue" 
synths? I know there are some expensive commercial systems around but I 
rather fancied having a go at something a bit cheaper. In the UK Maplin do 
an evaluation/development system for Analog Device's SHARC for under 180 
pounds. This has 16-bit stereo in/out and could easily emulate a typical 
monophonic synth in something the size of a paperback. The programming is 
the tricky part of course.

So, has anybody tried this or know of some good places on the web to look 
for relevant techniques and info? Thanks,

  ]\/[artin




From keen at austin.ibm.com  Wed Jul 15 00:22:13 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Tue, 14 Jul 98 17:22:13 -0500
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply? 
In-Reply-To: (Your message of Tue, 14 Jul 98 12:40:34 -0700.)
             <35ABB432.4CC0C64B@seanet.com>
Message-ID: <199807142222.RAA29940@keen.austin.ibm.com>

> ... that can be run off of a single ended power supply
>(in this case, a 9V battery).  I just like 9V batteries, OK?

For shame, Sean! Building guitar stompboxes again!  ;-)



From sasami at blaze.net.au  Wed Jul 15 00:34:34 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 15 Jul 1998 00:34:34 +0200 (MET DST)
Subject: AW: tubes, transistors......
Message-ID: <199807142234.AAA19603@mailhost.bpa.nl>

martink at cix.compulink.co.uk wrote
>While I'm sure that most analogue synths have their individual charms from 
>the *user's* point of view, if I were *designing* one I would be striving 
>for neutrality at every stage. If the synth user wants a tube sound it 
>should be possible to combine and program modules to mimic it. It could 
>even be available as some sort of preset although exactly what a tube 
>sound is probably varies with context.

Conversely, you could build a tube into your design, and have the real
thing, and this is the path a number of us are choosing to follow.

Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From sasami at blaze.net.au  Wed Jul 15 00:46:40 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 15 Jul 1998 00:46:40 +0200 (MET DST)
Subject: top octave chip
Message-ID: <199807142246.AAA19832@mailhost.bpa.nl>

Check out Keyboard systems ot http://www.systemsinfo.com/topdividers.html

They list what's available, and what can be substituted.

There's also a pic chip that generates a top octave, though I forget the url.

Ken.

>hi my name is Crystal and i've been lurking hereabouts for a while. i've
>found a lot of useful info and ideas. thanx all
> 
>i'm writing the list to see if anyone has a 50240 top octave synth chip
>they would like to trade or sell me. or if there's any source out there
>that has some for sale. thanx again
>
>
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From cyborg0 at GlobalEyes.net  Wed Jul 15 02:22:23 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Tue, 14 Jul 1998 19:22:23 -0500
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply?
References: <35ABB432.4CC0C64B@seanet.com>
Message-ID: <35ABF63F.A115A30F@globaleyes.net>

Sean Costello wrote:
> 
> Hi everyone:
> 
> I want to actually start building some of the circuits I have on my page
> (http://www.seanet.com/~costello), but I would like to make a few
> changes.  Specifically, I would like to create a diode ladder filter (a
> la the VCS3 or TB303) that can be run off of a single ended power supply
> (in this case, a 9V battery).  I just like 9V batteries, OK?
> 
Yes.. the BEST thing is the LTC1044ACN8 (for voltages up to 12 or 15
volts i think) OR the LTC1044CN8 (for voltages up to 9v)
These things can easily invert any voltage and do so with very low
ripple..I burned one of these up in a piece of gear the other day
(Syntecno TeeBee) and was amazed that all that was being done with just
ONE chip..wow!
Im sold on them.. i went out and bought 5 of em cuz I know of a billion
uses..
Linear Technologies has the data sheets on the web site.
rob



From pfperry at melbpc.org.au  Wed Jul 15 03:07:55 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 15 Jul 1998 11:07:55 +1000 (EST)
Subject: final post:   DEAD Nulogic sync24
Message-ID: <1.5.4.16.19961206174342.394794ee@popa.melbpc.org.au>

DO NOT MAIL ME! DO NOT MAIL ME!

An AH member has been trying to sell a NON_WORKING nulogic thingo,
and has been jerked around by 8 (eight) idiots who didn't follow through..

Now (at my suggestion) it is offered FREE to a good synth-diy home.

DONT MAIL ME, mail this person:

"JOY" <joy3 at cris.com>

Good luck guys & gals, the reputation of synth-diy is at stake!

paul perry melb australia







From pfperry at melbpc.org.au  Wed Jul 15 03:08:10 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 15 Jul 1998 11:08:10 +1000 (EST)
Subject: DSP anybody?
Message-ID: <1.5.4.16.19961206174357.3947b390@popa.melbpc.org.au>

At 09:05 PM 14/07/98 BST-1, martink at cix.compulink wrote:
>
>Is anybody on this list looking at using DSPs to create "analogue" 
>synths? 
...a chap is designing a commercial one for me....

I know there are some expensive commercial systems around but I 
>rather fancied having a go at something a bit cheaper. In the UK Maplin do 
>an evaluation/development system for Analog Device's SHARC for under 180 
>pounds. 
...we're using the Motorola 56303 evaluation board....

This has 16-bit stereo in/out and could easily emulate a typical 
>monophonic synth in something the size of a paperback. The programming is 
>the tricky part of course.
...HAHAHAHAHA!
>
>So, has anybody tried this or know of some good places on the web to look 
>for relevant techniques and info? 
...actually, despite a lot of looking, no good places found...
my friend was very depressed and thought that all the good algorithms were
probably developed and kept secret.. after a couple of months he went and 
listened to the Nord etc & found that their algorithms wern't up to his
standards anyway (or at least the output wasn't). So he is a bit happier now.
Looks like this is pretty cutting edge stuff.

Would naturally like to hear from any DSP people!

paul perry melbourne australia




From pfperry at melbpc.org.au  Wed Jul 15 03:08:14 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 15 Jul 1998 11:08:14 +1000 (EST)
Subject: "alternative controllers"
Message-ID: <1.5.4.16.19961206174401.3947b32c@popa.melbpc.org.au>

At 01:31 PM 14/07/98 -0700, gosd wrote:
 (lately i've been very
>interested in ribbon controllers) with anyone interested.happy
>synthesizing y'all

I think a toaster element, unwound and flattened out, would be a good CV source
using a sliding pipe with a wire to it as a potetiometer wiper in effect.
Probably put 6 v from a big latern battery across a couple of feet of element.

Has anyone made a hand spun LFO?
By putting magnets in a wheel and using a hall effect pickup you could get a 
nice effect, possibly.

paul perry, keeping it simple in Melbourne Australia




From OBERFELD at psych.gp.TU-Berlin.DE  Wed Jul 15 09:33:59 1998
From: OBERFELD at psych.gp.TU-Berlin.DE (Daniel Oberfeld)
Date: Wed, 15 Jul 1998 09:33:59 +0200
Subject: DSP: ADI-Dream?
Message-ID: <D852BD012B@psych.gp.tu-berlin.de>

Hi everybody,
nearly one year I waited for someone to use the ressources of the 
Analog Devices SHRC-DSPs combined with CSound, now finally the german 
manufacturer Creamware announced the SCOPE (that is a beauty..)

*BUT: all this might be possible for DIY!!*

Story is, ADI licensed CSound (a programming language for 
Sound-Synthesis, MIDI etc. developed by the MIT), extended it and 
optimized it for the SHARCs. 

Check

http://www.analog.com/techsupt/prod_briefs/ext_csound.html.

Some highlights from that page:

"Enhanced version of Public Csound, optimized in SHARCOE DSP assembly code. 

                       Currently offers more than 300 opcodes including 60 written exclusively for Analog Devices. 

                       Wavetables pulled from host RAM across PCI bus in real-time, eliminating the need for on-board
                       sample memory. 

                       Polyphony determined only by algorithm complexity and DSP power. As SHARC speeds increase,
                       so will the number of voices, thus lessening future hardware re-engineering. 

                       Windows 95OE Plug-and-Play compatible 

                       Full MIDI control of instruments parameters and controllers. MIDI implementation provides: 
                           -General MIDI w/ sysex 
                           -MIDI manager on DSP for low-latency keyboard response 
                           -Up to 6 virtual MIDI ports (max. 96 channels) 
                           -Exclusive key groups for drums 
                           -Efficient support of multiple wavetable libraries

                       Up to 6 channels audio out, 4 channels in 

                       Simultaneously runs a variety of synthesis techniques: 
                           -Additive 
                           -Subtractive 
                           -Wavetable 
                           -Waveguide 
                           -Waveshaping 
                           -Physical Modeling 
                           -Phase vocoder 
                           -Granular 
                           -FOF 
                           -LPC"
If anyone starts messing around with that, I'm in!!!!!

Daniel



From Juergen.Haible at nbgm.siemens.de  Wed Jul 15 10:53:36 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 15 Jul 1998 10:53:36 +0200
Subject: AW: Can a diode/transistor ladder filter be run from a single-end
	ed power supply?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58282FB0D@nbgm336a.nbgm.siemens.de>

Hi Sean, 

I'll try to give a few short answers:

	>Any ideas how I would go about this? 

Single ended is no problem - you can always create a
reference voltage a few volts above GND. You can either do 
it with an opamp buffer, or you can simply raise the dc level
of the cascade's differential amp with resistor dividers,
like the Moog cascade.
9V total supply voltage should be enough, but not exactly
abundance: the diodes eat approx. 5V, and you want some
space between the top of the ladder and 9V because of
the CMR of your buffer amplifier. The expo converter needs
some dc too.
I'd suggest to fix the low end of the cascade (bases of the
differential pair) to +1.5V, and the top of the cascade to
+7V. Make sure that the differential buffer amplifier after
the cascade works up to this voltage - a discrete circuit
(similar to the original VCS3) is a good idea here, or use
one of these modern rail to rail opamps. (I prefer the first
way.)

	>The tricky part is
	>the transistor(s) that convert the filter voltage control into the
	>exponential current needed for the diode ladder.  I could just copy
the
	>circuitry from the TB-303 

I don't have the 303 circuit in front of me now, but if memory serves
they had more dc "space" for the converter than you wil have.
(wasn't that 12 or even 15V supply, with the reference voltage
at approx. 5V ? )
I suggest a current mirror here, together with a pnp expo converter.

	>Any other issues I would encounter with running the VCS3 filter off
of
	>+9V?  How about the diodes at the "top" of the ladder (i.e. the 3
pairs
	>above the main R/C diode pairs)?  What do they do? 

If you're careful with calculating dc bias points all over your circuit,
a 9V design should be fine.
The 3 diodes at the end is simply a 3R termination of the unbuffered
4-pole RC filter. You can see its influence if you draw a little
simplified circuit: an AC *current* source (the signal current from
the differential pair) feeding a C to GND and an R to the next
stage, another C to GND, R to the next stage, and so on. The last
stage has C and 3R to GND. (You can simulate this with any free
Spice demo version. Add a variable gain stage for the feedback loop,
and you can see why this 4pole filter is called "18dB" filter with good
reason, btw.)
>  
	>Also, could the TB-303 expo stage be used in a Moog ladder filter?
Can
	>the Moog ladder filter run off of a 9V battery?  The schematics for
the
	>discrete Moog filters (Minimoog, 904a) seem to only use the
negative
	>supply for the exponential convertor.  Can these be converted to
run off
	>of a single ended supply?  Advantages, disadvantages?

I don't see much problems here. While the diode ladder has its
dc shift from stage to stage determined by the diode drop voltage,
the transistor ladder's dc shift is determined by the base voltages,
i.e. the resistor divider. Don't remember the original Moog voltage
spacing, but the ladder will surely work if it's just slightly above the 
be voltage drop. And you don't have the 3R termination here.
So, with a little care, no problem. Expo converter same as above.

	>I'm also interested in creating an MS-20 filter section clone that
is
	>battery operated (I LOVE battery operated boxes - my little x0x
boxes
	>are getting a lot of use nowadays, while I wait for the NM to
arrive).
	>Any advice there?  It seems more straightforward - just using a
voltage
	>divider to create a "virtual ground" that is 1/2 of the positive
supply.
	>Any other tricks?

The MS-20 filter 9V adaption looks easy, but be careful with the soft
limiting of the opamps (the diodes ...) You will have to recalculate
this completely. And rail to rail opamps are highly recommended here. 

JH.




From shudder at optusnet.com.au  Wed Jul 15 11:03:08 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Wed, 15 Jul 1998 19:03:08 +1000
Subject: [sdiy] Yet another analogue synth
Message-ID: <005801bdafcf$69be1d40$2f2c8ec6@dialup.mpx.com.au>

Here's a rundown:
http://www.chipcenter.com/circuitcellar/august99/c89r4.htm
Sean

-----Original Message-----
From: ElmacacoX at aol.com <ElmacacoX at aol.com>
To: harrybissell at prodigy.net <harrybissell at prodigy.net>; ElmacacoX at aol.com
<ElmacacoX at aol.com>; star at all-carrs.demon.co.uk
<star at all-carrs.demon.co.uk>; synth-diy at node12b53.a2000.nl
<synth-diy at node12b53.a2000.nl>
Date: Wednesday, 23 May 2001 8:40
Subject: Re: [sdiy] Yet another analogue synth


is there such thing as blue noise?




From Juergen.Haible at nbgm.siemens.de  Wed Jul 15 11:08:20 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 15 Jul 1998 11:08:20 +0200
Subject: AW: motorised pots
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58282FB49@nbgm336a.nbgm.siemens.de>

	>I can get some twin 10k ones but 1. they look pretty cheapo and
	>2. they take 10 seconds to travel around! which makes them useless 
	>for the effects processor I am designing.
	>I was hoping to have the pots rotate to the appropriate positions
	>when a patch is called up from memory. I notice that even the
latest 
	>Yamaha guitar amps have 96 memories and rotating knobs!!!!!

Personally, I could even live with all motorized potentiometers 
of a synth travelling to their new positions one by one, saving
power and taking even more time. Must look very cool,
a "ghost finger" wandering from one knob to the next, until
all are set. Not good for switching a guitar amp from rhythm to
lead, but might give "morphing" a new meaning.

If you find a good (analogue) control circuit, please tell me.
An opamp that compares the set voltage with the momentary
potentiometer voltage, and thus drives the motor forward and backward,
would be all that's needed. But designing the right time constant, and
probably a little tolerance window where the motor doesn't move,
might be some amount of work.

JH.



From Juergen.Haible at nbgm.siemens.de  Wed Jul 15 11:18:39 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 15 Jul 1998 11:18:39 +0200
Subject: AW: tubes, transistors......
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58282FB6F@nbgm336a.nbgm.siemens.de>

	>In a message dated 98-07-13 13:54:28 EDT, ebarbour at svetlana.com
writes:
	>
	><< Sorry, John, you have a LOT to learn. >>
	>
	>Sure do, and glad of it. Knowing it all already is obviously a very
	>frustrating proposition :-)
	>
	>I guess part of the problem is that I'm sometimes quoted as an
"expert" when
	>in my own mind I'm nothing of the sort. Just another guy exploring
the world
	>and sharing what I find.
	>
	>-John


Very well spoken, John. 
Better to *be* an expert than telling everybody so.
Being in business as long as you are, and still helpful to anybody
who asks, speaks for itself.
Keep up the good work !

JH.



From daniel8891 at yahoo.com  Wed Jul 15 11:48:21 1998
From: daniel8891 at yahoo.com (daniel8891 at yahoo.com)
Date: Wed, 15 Jul 1998 11:48:21 +0200 (MET DST)
Subject: re your web site
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From OBERFELD at psych.gp.TU-Berlin.DE  Wed Jul 15 11:52:02 1998
From: OBERFELD at psych.gp.TU-Berlin.DE (Daniel Oberfeld)
Date: Wed, 15 Jul 1998 11:52:02 +0200
Subject: DSP: ADI-Dream?
Message-ID: <DA9F8C43FA@psych.gp.tu-berlin.de>

Hi everybody,
nearly one year I waited for someone to use the ressources of the 
Analog Devices SHRC-DSPs combined with CSound, now finally the german 
manufacturer Creamware announced the SCOPE (that is a beauty..)

*BUT: all this might be possible for DIY!!*********

The story is, ADI licensed CSound (a programming language for 
Sound-Synthesis, MIDI etc. developed by the MIT), extended it and 
optimized it for the SHARCs. 

Check

http://www.analog.com/techsupt/prod_briefs/ext_csound.html.

Some highlights from that page:

"Enhanced version of Public Csound, optimized in SHARC DSP assembly code. 

                       Currently offers more than 300 opcodes including 60 written exclusively for Analog Devices. 

                       Wavetables pulled from host RAM across PCI bus in real-time, eliminating the need for on-board
                       sample memory. 

                       Polyphony determined only by algorithm complexity and DSP power. As SHARC speeds increase,
                       so will the number of voices, thus lessening future hardware re-engineering. 

                       Windows 95 Plug-and-Play compatible 

                       Full MIDI control of instruments parameters and controllers. MIDI implementation provides: 
                           -General MIDI w/ sysex 
                           -MIDI manager on DSP for low-latency keyboard response 
                           -Up to 6 virtual MIDI ports (max. 96 channels) 
                           -Exclusive key groups for drums 
                           -Efficient support of multiple wavetable libraries

                       Up to 6 channels audio out, 4 channels in 

                       Simultaneously runs a variety of synthesis techniques: 
                           -Additive 
                           -Subtractive 
                           -Wavetable 
                           -Waveguide 
                           -Waveshaping 
                           -Physical Modeling 
                           -Phase vocoder 
                           -Granular 
                           -FOF 
                           -LPC"

If anyone wants to start messing around with that, I'm in!!!!! Or is there 
maybe someone out there who is already working with that environment?

Daniel



From pfperry at melbpc.org.au  Wed Jul 15 15:06:48 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 15 Jul 1998 23:06:48 +1000 (EST)
Subject: AW: motorised pots
Message-ID: <1.5.4.16.19961207054243.0f9f8396@popa.melbpc.org.au>

At 11:08 AM 15/07/98 +0200, JH. wrote:

>Personally, I could even live with all motorized potentiometers 
>of a synth travelling to their new positions one by one,.......
>If you find a good (analogue) control circuit, please tell me.
>An opamp that compares the set voltage with the momentary
>potentiometer voltage, and thus drives the motor forward and backward,
>would be all that's needed. But designing the right time constant, and
>probably a little tolerance window where the motor doesn't move,
>might be some amount of work.

the place to look for ckts would be amateur robotics, because pots are often
used to
determine when the correct rotational or linear position has been
reached..you can 
find astoundingly precise and expensive ones in the USA surplus dealers
catalogs.

paul perry melbourne australia
BTW the 'cheap' motor pots I mentioned just have 2 wires coming from the
motor, so to reverse you 
reverse the current... you could rely on this motor to have plenty of 'dead
space', you bet!





From chordman at flash.net  Wed Jul 15 15:28:52 1998
From: chordman at flash.net (chordman at flash.net)
Date: Wed, 15 Jul 1998 15:28:52 +0200 (MET DST)
Subject: Chua Oscillator question
Message-ID: <199807151328.PAA00816@mailhost.bpa.nl>


I've looked at several sites now and I still have questions.
Has anyone made one of these work with a voltage controlled
bandpass filter?  One of the circuits on the web shows the
classical circuit with dotted lines coming from the caps and
resistors in the filter that go back to a box labeled 'MIDI
Control'.  Kind of vague for me.  Also, the circuit looks like
both terminals of the filter are both inputs and outputs at
the same time...  Almost as if it is an electronic analog of
a reed and a resonator.  Anyway, I've a mental block with it,
but I really want to make one.

-- Scott Gravenhorst
-- FatMan Site: http://www.teklab.com/~chordman
-- RedWebMail by <R<edStarWare





From thudson at cygnus.com  Wed Jul 15 15:33:01 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Wed, 15 Jul 1998 09:33:01 -0400
Subject: DSP anybody?
References: <1.5.4.16.19961206174357.3947b390@popa.melbpc.org.au>
Message-ID: <35ACAF8D.199CB6E9@cygnus.com>

Paul Perry wrote:
> Looks like this is pretty cutting edge stuff.
> 
> Would naturally like to hear from any DSP people!
> 
There is a music-dsp mailing list that is quite informative.
See http://shoko.calarts.edu/~glmrboy/musicdsp/music-dsp.html

Thomas



From Chris.List at sc.siemens.com  Wed Jul 15 15:36:17 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 15 Jul 1998 09:36:17 -0400
Subject: Faceplate Lamination
Message-ID: <81A062BC5305D111A9D700805F065968CE9454@maildepo.sc.siemens.com>

Just thought I'd let you guys know, last night I tried Gene's method of
faceplate making -

1. Print on regular paper
2. Get it laminated at a photoshop
3. Glue it to the panel

I was very pleased with the results. It may not be the prettiest
solution in the world, and time will tell as to it's durability, but
it's **so cheap and easy** that it's almost irresistible. The laminate
is also surprisingly strong as far as scratch resistance goes. Come to
think of it, now that I've had some of my home-built panels for a couple
of years, I've come to realize that all of my fretting about durability
was a little exaggerated - I mean, when something's mounted in a rack,
what would happen to cause the edges to peel away from the plate? Your
stuff is really pretty well protected - unless you're making a tabletop
unit... The only thing you really need to worry about is scratch
resistance. Even if the glue fails, you've got all the components
holding it in place.

Anyway, a couple of things that helped make this easy were;

1. I used one of the blank rack panels that Mouser sells (they come in
gray and metallic black) - these are the cheapest aluminum rack panels
I've seen anywhere - possibly because they are powder-coated rather than
anodized. This turns out to be a good thing, as I the adhesive seems to
stick better to these than to the anodized panels I've worked with.

2. I used "3M Spray 77" adhesive, available at art supply stores. This
stuff gives you about 15-30 seconds of "tack time" where you can slide
around the laminate, then dries to a really strong bond. The strength of
the laminate to panel bond is stronger than the bond between the two
layers of laminate! The glue is a little bit of a drag to work with
because you should spray both the panel and the back of the laminate for
a good bond. Once you do that, picking up the laminate and flipping it
onto the panel will surely get some of this tacky stuff on your fingers
- and then onto the front of the panel. Luckily, you can wash it after
it dries with a little soap on a course sponge without affecting the
panel or the glue... 

Considering the cost, it's worth trying for anyone. Thanks to Gene Stopp
for recommending it.

- CList 



From mfay at fs2.cp.umist.ac.uk  Wed Jul 15 14:23:06 1998
From: mfay at fs2.cp.umist.ac.uk (Martin Fay)
Date: Wed, 15 Jul 1998 14:23:06 BST
Subject: DSP anybody?
In-Reply-To: <memo.567817@cix.compulink.co.uk>
Message-ID: <214BA552C99@fs2.cp.umist.ac.uk>

Martin Keefe wrote:
> Is anybody on this list looking at using DSPs to create "analogue"
> synths?

Sort of...but my development is x86/win32 based, a major advantage of 
this being the excellent development tools available, and also a wide 
choice of audio and MIDI interfaces.

> In the
> UK Maplin do an evaluation/development system for Analog Device's
> SHARC for under 180 pounds.

That sounds interesting, do you have more details handy? I'm sure I 
can find a Maplin catalogue somewhere but I doubt people outside the 
uk can as easily.


Martin

  man(i)kin / 3 track demo now available on mp3
+------------------------------------------------+
| Email: martin.fay at umist.ac.uk                  |
| Web: http://www.cp.umist.ac.uk/users/martin/   |
+------------------------------------------------+
| See web site for:                              |
| VAZ: Vurtual Analogue Synth Emulator           |
| Demos on mp3: man(i)kin, Curious Yellow        |
+------------------------------------------------+



From keen at austin.ibm.com  Wed Jul 15 16:41:03 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Wed, 15 Jul 98 09:41:03 -0500
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply? 
In-Reply-To: (Your message of Tue, 14 Jul 98 17:22:13 -0500.)
             <199807142222.RAA29940@keen.austin.ibm.com>
Message-ID: <199807151441.JAA12828@keen.austin.ibm.com>


> ... that can be run off of a single ended power supply
>(in this case, a 9V battery).  I just like 9V batteries, OK?

I forgot to mention - I've successfully run a Mutron III clone on a 2"
by 3" PCB from a single 9V battery and a 7660 charge pumped voltage 
converter. I was worried that I'd get intractable 10KHz whine from 
the converter, but by separating the power ground from the battery 
and the analog ground and some judicious filtering, there isn't any 
whine audible in the audio (!?! don'cha love knarled English?). 

You could probably make a diode filter ladder run just fine that 
way. Certainly enough volts there.



From aschrock at cs.brandeis.edu  Wed Jul 15 17:18:23 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 15 Jul 1998 11:18:23 -0400 (EDT)
Subject: Faceplate Lamination
In-Reply-To: <81A062BC5305D111A9D700805F065968CE9454@maildepo.sc.siemens.com>
Message-ID: <Pine.HPP.3.95.980715104322.11566A-100000@bay.cs.brandeis.edu>

On Wed, 15 Jul 1998, List, Christopher wrote:
> I was very pleased with the results. It may not be the prettiest
> solution in the world, and time will tell as to it's durability, but
> it's **so cheap and easy** that it's almost irresistible. The laminate
> is also surprisingly strong as far as scratch resistance goes. Come to
> think of it, now that I've had some of my home-built panels for a couple
> of years, I've come to realize that all of my fretting about durability
> was a little exaggerated - I mean, when something's mounted in a rack,
> what would happen to cause the edges to peel away from the plate? Your
> stuff is really pretty well protected - unless you're making a tabletop
> unit... The only thing you really need to worry about is scratch
> resistance. Even if the glue fails, you've got all the components
> holding it in place.

I'm strangely enough moving away from large rackmounted devices. I've 
realized that part of what I like about my synths is 1) their portability
and 2) their usefulness.. each one fufills a specific purpose, and I can
mix and match each of them depending on the purpose I have in mind.. 3) I
like putting patches together on my bed :) 

I've shrunk my rack spaces down to 1 10 space rack and 1 4 space rack, and
ditched the 12 space rack. A dorm room is only so big, yknow.. I don't
like the space that's wasted in a rackmounted case, either, unless you get
a low-profile rack. 

I recently moved my MAP drum machines into a radio shack case. It fits
nicely by my mc-202 and sh-101, and is quite sturdy even if its not
totally professional-looking. My asm-1 is in a cardboard box right now,
but I'll move it to some sort of plastic case in the near future. Even the
modular I'm currently building is going to be housed behind a somewhat
small (16"x12") front panel. 

On another note, assembly of my modular and accompanying mini-synth is
going well. I've vectorboarded/tested the VCAs and VCOs, (on $1.25 rat
shack vectorboard) and placed my order for a MOTM-100. Still left to do
are the ringmod, VCFs, and ADSRs (3 of em!). This is going to be an
extremely handy little beast, especially combined with my asm-1.. I'll put
pics of the synth in progress up on the web sometime and give the web
address for them after I've recieved the front panels from Germany and
install a few modules/jacks so people will have a good idea of where I'm
going with the project. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|







From Juergen.Haible at nbgm.siemens.de  Wed Jul 15 17:46:39 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 15 Jul 1998 17:46:39 +0200
Subject: A Phase Modulation idea (was: Nonlinear Oscillators?)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58283B690@nbgm336a.nbgm.siemens.de>


Sean wrote:

	>Hmm...isn't Yamaha FM based on phase modulation, as opposed to
strict
	>frequency modulation?  If so, are there any analog oscillator
designs
	>that allow phase to be controlled directly?  

Ok, this is only a very rough thought so far, but being the lazy guy I am,
I'm posting it before I've tried it myself:

Changing the phase of an oscillator by a certain amount should
be equivalent to changing the voltage of the VCO's integrating
capacitor by a certain amount, by definition. 

Someone suggested a d/dt function on an ordinary FM input, but
as he said, that's not exactly practical. But if we consider that the
VCO's capacitor performs a perfect integration on a FM *current*
(as well as on the dc current that sets the initial frequency), the
hypothetical d/dt function and the integrator function of the cap
would cancel. So how to change the capacitor voltage directly
with a modulation voltage ?

First throw would be a low impedance path that "forces" the cap
into a certain direction (opamp buffer + small resistor), but this
does not work as there is no means to mix in the normal VCO
control current.

Second throw (and this is what I want to propose here): Capacitance
voltage divider ! 
Similar as in my "linear detuning" circuit.
Feed in your modulation signal from a low impedance buffer directly 
to the VCO's integration cap by means of another capacitor !
The control current for "normal" operation will see the two caps in
parallel, so you have to recalculate your initial frequency a little.
No problem, as this will be constant for any modulation depth.
The "PM" path will see a (capacitive) voltage divider, so everything
will go straight thru, just linearly attenuated by the ratio of the two 
capacitance values. Even pulse waves (with finite rise time, of
course) will be no problem, as long as the buffer is strong enough
and can drive a capacitive load. (Not trivial, but not impossible either.)

So, where is the problem ?
Honestly, I can hardly believe that it should work. So far I have not 
considered the nonlinear effects, i.e. what happens when the capacitor
is discharged. The saw wave oscillator case would be simpler here
(though I have not explored that completely), but what about a triangle
based VCO ? For any effective linear modulation we need thru zero 
modulation, so that would be "Thru Zero PM" in that case. So probably
there is some switching and syncing required, but after all the whole scheme
is not *that* far away from phase increments during read out of a lookup
table (they also have to handle a limited adress range before there is
some "reset") - so maybe there is a realistic chance to get it working.

What do you think ?

JH. 




From chordman at flash.net  Wed Jul 15 17:53:35 1998
From: chordman at flash.net (chordman at flash.net)
Date: Wed, 15 Jul 1998 17:53:35 +0200 (MET DST)
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply?
Message-ID: <199807151553.RAA04106@mailhost.bpa.nl>


keen at eden.com wrote:
>
>> ... that can be run off of a single ended power supply
>>(in this case, a 9V battery).  I just like 9V batteries, OK?

Would the opamp virtual ground work here?

-- Scott Gravenhorst
-- FatMan Site: http://www.teklab.com/~chordman
-- RedWebMail by <R<edStarWare





From OBERFELD at psych.gp.TU-Berlin.DE  Wed Jul 15 17:53:52 1998
From: OBERFELD at psych.gp.TU-Berlin.DE (Daniel Oberfeld)
Date: Wed, 15 Jul 1998 17:53:52 +0200
Subject: Nonlinear vs. chaotic
Message-ID: <E0A795142F@psych.gp.tu-berlin.de>

Hi all,
> I would love to have a musical instrument
>that
	>could jump octaves like a wind instrument (i.e. with the same sort
>of
	>noisy transition, not just clean octave jumps), or generate chaotic
	>subharmonics like a Gyuto monk, or growl like a sax, or create

One point I'd like to make: you have to consider 'nonlinear' and 
chaotic seperately.
Most 'natural' sound-sources (Strings, reeds, tubes) are certainly 
nonlinear in several aspects but do not exhibit chaotic behavior.
On the other hand, nonlinear system (e.g. oscillators) can produce 
chaotic 'timeseries'.

Personally, I don't think chaotic systems are useful for musical 
synthesis, because chaotic sounds are best described as "irregular, 
unpredictable, noisy, uncontrollable, dirty and wild" (Bruno Degazio: 
Twards a chaotic musical instrument, 1993). Some aspects 
here are contrary to everyday musical use and benefit.

Nonlinear oscillators on the other hand can show interesting 
behaviour like amplitude dependent harmonic structure (think of hard 
stroked Rhodes reeds), the mentioned octave jumps (overblown 
Saxophone) or special attack/decay behaviour like descending pitch 
(bass drum). 

All these physical systems are quite straight-forward described (in 
an oversimplified manner, I have to admit) in readily available 
differential equations (see my other posting for literature). These, 
on the other hand, are easily implemented in 'analog computers 
(Op-amp integrator and differentiator systems like state-variable 
VCFs). Hal Chamberlin has some examples in his "Musical applications 
for Microprocessors"

Daniel



From johns at oei.com  Wed Jul 15 18:17:08 1998
From: johns at oei.com (John Speth)
Date: Wed, 15 Jul 1998 09:17:08 -0700
Subject: AW: motorised pots
Message-ID: <01BDAFD1.5B1D1460@johns.oei.com>

I remember that Mouser sold motorized pots a couple of years ago.  I haven't seen them in their catalog lately though but I haven't been specifically looking for them either.  I wonder if they still can get them.

But in application, someone mentioned something about a "good analog control" circuit for these things.  It seems to me that a motorized pot (even moreso, multiple motorized pots) beg to be controlled by an embedded cpu.  All the loop functions and data recall and storage could be best served in software.  The only analog circuitry you'd need is that which will provide current drive for the motor and an ADC for position feedback.  Isn't that why you usually see twinned pots?  --> one for your application circuit and one for feedback to your controller for position information.  I've never used one of these but can somebody enlighten me on other applications?

Imagine a primo modular synth with motorized pots and LEDs for indicating cable patching end points!!  You get the flexibility of programming a modular with the ability to recall patches with the assistance of software.  That's my dream instrument (a la NASA budget)!

John Speth
Object Engineering, Inc.
mailto:johns at oei.com





From martink at cix.compulink.co.uk  Wed Jul 15 16:33:00 1998
From: martink at cix.compulink.co.uk (Martin Keefe)
Date: Wed, 15 Jul 98 16:33 BST-1
Subject: AW: DSP anybody?
Message-ID: <memo.598700@cix.compulink.co.uk>

In-Reply-To: <06E83B40290BD111B41B08002BB769DAC5AFD2 at balu.kapsch.co.at>
> Sound generator (sawtooth / rectangle / PW adjust)
> LFO (sine wave / sawtooth )
> Envelope generator
> 
> So I only showed that it is possible but I stopped when I wanted to
> calculate a filter on the fly as my mathematical knowledge is not
> very sophisticated and my time is very limited. But maybe some day
> I could go one with this project.

Yep, I thought those would be the first step as they are fairly straight 
forward. The next stage is some filtering and this is slightly more 
complicated as it needs some "history" (and optionally some "future"!) of 
the signal. A basic FIR and/or IIR is simple in principle -- just weighted 
sums of surrounding samples. Calculating the weights is less obvious but 
must be covered in some standard text. Its off to amazon.com for me!

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




From martink at cix.compulink.co.uk  Wed Jul 15 16:33:00 1998
From: martink at cix.compulink.co.uk (Martin Keefe)
Date: Wed, 15 Jul 98 16:33 BST-1
Subject: DSP anybody?
Message-ID: <memo.598696@cix.compulink.co.uk>

In-Reply-To: <214BA552C99 at fs2.cp.umist.ac.uk>
> > In the
> > UK Maplin do an evaluation/development system for Analog Device's
> > SHARC for under 180 pounds.
> 
> That sounds interesting, do you have more details handy? I'm sure I 
> can find a Maplin catalogue somewhere but I doubt people outside the 
> uk can as easily.

I've just ordered one so I'll have more info in a day or two. Meanwhile 
the details on page 913 of the current catalogue are:-

SHARC EZ-Kit Lite
-----------------
Now with this easy-to-use development kit designers with no DSP 
experience, can soon master Analog Devices SHARC 32-bit floating  point 
DSPs. The SHARC EZ-KIT Lite is a complete package for DSP evaluation and 
prototyping, containing all the essential tools for the development of a 
DSP design. The DSP development board includes:-
* ADSP21061 SHARC processor running at 40MHz
* UART - RS232 interface
* AD1847 SoundPort audio CODEC
* Line in/out with stereo jacks
* MIC in with stereo jack
* Socketed EPROM - firmware includes an power on self-test with audio
  report and RS232 based bootstrap loader
* Power regulator
* Power LED and 4 flag LEDs
The powerful software and the SHARC's large on-chip memory allows the 
designer to run very sophisticated programs. Code development and 
prototyping tools are:
* Assembler, linker, instruction level simulator, C compiler with
  numerical C extensions
* C source level debugger, and C runtime library
* A kernel for the SHARC for power on self-test and host interface
* A host-based Windows 3.1 uploader/downloader to allow the user
  to perform data uploads and downloads from/to the target SHARC
  EZ-KIT Lite
* Diagnostic utilities to control program operation and access
  DSP memory
Supplied with RS232 cable and a 9V DC power supply with SHARC users manual 
and development CD-ROM with SHARC development tools, EZ-KIT Lite manual 
and tutorial.

Order Code: NP42V  Price ec. VAT: ?153.00  Price inc. VAT: ?179.98


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




From martink at cix.compulink.co.uk  Wed Jul 15 16:33:00 1998
From: martink at cix.compulink.co.uk (Martin Keefe)
Date: Wed, 15 Jul 98 16:33 BST-1
Subject: DSP: ADI-Dream?
Message-ID: <memo.598704@cix.compulink.co.uk>

In-Reply-To: <D852BD012B at psych.gp.tu-berlin.de>

I'd seen that page on the Analog Devices site but couldn't find any 
indication of price. Anybody know? 

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




From oakley at enterprise.net  Wed Jul 15 21:32:17 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Wed, 15 Jul 1998 20:32:17 +0100
Subject: motorised pots
Message-ID: <000801bdb027$95624360$10c548c2@default>


JH said:
If you find a good (analogue) control circuit, please tell me.
An opamp that compares the set voltage with the momentary
potentiometer voltage, and thus drives the motor forward and backward,
would be all that's needed. But designing the right time constant, and
probably a little tolerance window where the motor doesn't move,
might be some amount of work.

I designed the motorised sliders on the Soundcraft desks... not easy.
Especially if the load on the motor changes with position or batch. We used
a DAC in the feedback loop which controlled the loop gain. This way the desk
could be programmed with all the different loop gains needed for each
individual pot. Bear in mind as the pots wear out they get sticky and this
has to lead to updated values of loop gain. This was done automatically
everytime the desk was powered up. However, if your motorised pots are good
ones and you are not to bothered with speed you could get away with a single
op-amp servo loop. Switch off the power to motor when the value is reached
to save energy.
For circuit ideas try looking at the various hi-fi's that have motorised
volume pots.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

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

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







From pwayman at laserfiche.com  Wed Jul 15 23:42:10 1998
From: pwayman at laserfiche.com (Peter Wayman)
Date: Wed, 15 Jul 1998 14:42:10 -0700
Subject: motorised pots -Reply
Message-ID: <98Jul15.144217pdt.12546@cerberus.laserfiche.com>

Suggestion: How about the little servos that are
used by Radio Control hobbyists? ~US$30 each...
they are quite strong and I think all the feedback
controls are self contained.


:P




From smart at nn.com  Wed Jul 15 23:42:26 1998
From: smart at nn.com (Mark Smart)
Date: Wed, 15 Jul 1998 16:42:26 -0500 (CDT)
Subject: motorised pots
Message-ID: <199807152142.QAA08663@medusa.nn.com>

> JH said:
> If you find a good (analogue) control circuit, please tell me.
> An opamp that compares the set voltage with the momentary
> potentiometer voltage, and thus drives the motor forward and backward,
> would be all that's needed. But designing the right time constant, and
> probably a little tolerance window where the motor doesn't move,
> might be some amount of work.

Hey, after lurking on this list for a long time, I can contribute
something! I have been trying to figure out how to do this for a long time
using exactly the type of op-amp position regulator circuit which was
mentioned before. I wanted to incorporate this into my massive GR-300
guitar-synth-hacking project. The cheapo motorized pots which another
earlier post metioned are probably the same ones I am using. They're from
Mouser, they are rotary, and only $10 each. And you can still turn the knob
by hand without messing everything up, since there's a little clutch
inside.

I tried several circuits to get this to work. I actually got one that
worked (albeit VERY slowly) with an LF351 op-amp. But it was too slow, and
I'm sure the op-amp wouldn't survive for very long, it was not designed for
that kind of load! So I looked at power op-amps. I was thinking about
using an LM1877, but it has a limit of 0.7V limit on input voltage, which
made it useless in my circuit. I also tried an LM1876, and I couldn't get
that to work either. It behaved very erratically. I don't think these chips
were intended to do DC stuff.

Then this last week I was cleaning out my office at work and found a really
old SGS Thomson data book. There is a power op-amp in it called the L272,
and an example circuit for "automobile headlight positioning" which looks
like exactly what is needed. There are two selector switches, one of which
is mechanically connected to the motor. The selector switches are wired as
voltage dividers with resistors between their output terminals, so it
looks like they could easily be replaced with pots.

Another interesting part about this circuit is that it uses two op-amps
whose outputs go to the pins of the motor. Hence you get bidirectionality
with a single supply. I have ordered a couple of L272's and am going to try
this when they get here. 

I looked on the SGS thomson web site, and there are data sheets there for
this chip. However, the "headlight" circuit is not included in them
anymore. My databook is from like 1984 and is called "power linear
actuators". I suppose I could copy the schematic for people if they want,
or scan it and email it. I have no idea if it really works. It runs on
12volts, but I'm sure it can easily be adapted for use with these 5V
motorized pots.

I have looked around (including in amateur robotics books) for a servo
circuit which DIDN'T use PWM, and it seems to be a real rarity. I always
wanted to avoid PWM because of the potential noise problems on audio gear.


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From magnus at analogue.org  Thu Jul 16 00:10:50 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 16 Jul 1998 00:10:50 +0200
Subject: AW: tubes, transistors......
In-Reply-To: Your message of "Tue, 14 Jul 1998 11:32:41 -0500"
References: <3.0.5.32.19980714113241.007b3be0@192.168.210.18>
Message-ID: <199807152208.AAA11741@piraya.electrum.kth.se>

>>>>> "BL" == Bill Layer <b.layer at vikingelectronics.com> writes:

Hi All!

 BL> Juergen's comments have raised a deep and perplexing Zen-type issue, that
 BL> is: What is the actual sound of an electronic instrument? The design or the
 BL> parts or the patch or???? (and you thought I was going to ask what is the
 BL> sound of one bifet clapping!)

 BL> A logically related question is: what is the sound of an instrument, if not
 BL> the sum of it's fundamental and distortion products, irrespective of the
 BL> source of that distortion? How is it defined? How should we define it?

Somewhere in the back of my head I recall a old truth that "90% of a
instruments character is in it's transient". This means that in the
attack part of a tone you have much more information about the
instrument. Imitating the attack of a grand piano is much more
difficult than imitating the sustain-part.

This is also consitent with Eric's point about transient properties of
tubes.

The rule is however not really well appropriate for new type of
instruments where you may do a lot of dirty tricks in the loooong
sustain period.

 BL> Finally, the most intersting question of all arises: Where does the
 BL> instrument begin and end? This is even more puzzling if you consider a
 BL> modular system, where the issue is most cloudy. 

There is guitarists that consider their amps and integral part of
their instrument.

I think that a really interesting aspect is the instruments use.
I know many examples of sounds that when listened to all alone they
are so flat, naive, nose or something similar that you would just pass
by it and simply not use it, it was not a good sound, where they
become THE little sound that when correctly used puts a very
colourfull spice to a allready very good piece. Go listen to Vangelis
to find noumerous examples. So, where does the instrument end now?

 BL> Now that I've brought this zen discussion to the table, a bit of my own
 BL> un-zenlike dogma. I think that electroinc instruments are being used at
 BL> their worst and weakest, when one endeavours to duplicate the sound of a
 BL> real accoustic instrument; that is: the original goal of music synthesis
 BL> (that of flawless emulation), is just flat pointless and moreover,
 BL> tasteless (don't agree? listen to Switched on Brandenburgs or anything by
 BL> Tomita EXCEPT for the Englufed Cathedral) for any purposes other than
 BL> academic.

 BL> I for one would NEVER tolerate transistor artifacts in my stereo PERIOD,
 BL> but on the other hand, I think they are fine for Emusic apps, INCLUDING
 BL> signal processing. Why this apparent contradiction? Because IMO, there is
 BL> nothing inherently 'correct', genuine  or natural about the sound of an
 BL> eMusic instrument, but there IS something inherently correct about the
 BL> manner in which it is reproduced.

Sometimes you end up with subjectivites one way or another. In many
cases you may conclude that something is stupid or wierd to be using
since this or that product is "better" but what eventually counts is
how they are being used and how the musician feels about using it,
that is certainly subjective. Some instruments certainly lends
themselfs for a certain class of sounds and music where as they can do
a lot more... I have even heard a guy play a Hammond in a very diffrent
way than we are used to hear them... this was a real intriguing thing
to hear and is also BTW one of my favorite albums...

So, to some degree one comes into the "Whatever works for you".

BTW. There is one place where tubes have a special case, and that is
radio and TV transmitters. For these apps I hardly think that solid
state will compete in the same way for the same functionallity for
still some time. You can get tubes capable of about 500 kW of RF
power, so if anyone want to build a stadium PA power amp just surf
over to Siemens and download their RF tube catalog in PDF format.
Oh, keep some distance from these tubes, they have X-ray problems and
you will need watercooling.

Cheers,
Magnus



From magnus at analogue.org  Thu Jul 16 00:37:11 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 16 Jul 1998 00:37:11 +0200
Subject: Can a diode/transistor ladder filter be run from a single-ended power supply?
In-Reply-To: Your message of "Tue, 14 Jul 1998 12:40:34 -0700"
References: <35ABB432.4CC0C64B@seanet.com>
Message-ID: <199807152235.AAA11917@piraya.electrum.kth.se>

>>>>> "SC" == Sean Costello <costello at seanet.com> writes:

 SC> Hi everyone:
 SC> I want to actually start building some of the circuits I have on my page
 SC> (http://www.seanet.com/~costello), but I would like to make a few
 SC> changes.  Specifically, I would like to create a diode ladder filter (a
 SC> la the VCS3 or TB303) that can be run off of a single ended power supply
 SC> (in this case, a 9V battery).  I just like 9V batteries, OK?

Building for 9V should not be such a big problem, but something in the
back of my head says that it could do well with some more voltage.

You will not need to have all the 0.7 V over each diode even if that
would not be much of a disaster in 9V.

 SC> Any ideas how I would go about this?  I know the TB-303 uses a single
 SC> ended power supply, so I know that it is possible.  The tricky part is
 SC> the transistor(s) that convert the filter voltage control into the
 SC> exponential current needed for the diode ladder.  I could just copy the
 SC> circuitry from the TB-303 (it is pretty darned nifty, with the "gimmick"
 SC> for lowering the cutoff frequency while increasing the envelope
 SC> modulation), but I would really like to know what I am doing before I
 SC> start.  I really don't want to simply clone the 303 filter; I'd like to
 SC> adapt the core of the VCS3 filter (check my page for a reasonable clone
 SC> of the VCS3 filter), and possibly use germanium diodes for the filter.

So 1N914/1N4148 isn't good enought for you?

 SC> Any other issues I would encounter with running the VCS3 filter off of
 SC> +9V?  How about the diodes at the "top" of the ladder (i.e. the 3 pairs
 SC> above the main R/C diode pairs)?  What do they do?  

The diodes on the top creates a much more diffrent ending to earth
than just one dioded per leg would. This changes the characteristics
of the sound. The diodes would change their transconductance just as
the other diodes will.

 SC> Also, could the TB-303 expo stage be used in a Moog ladder filter?  Can
 SC> the Moog ladder filter run off of a 9V battery?  The schematics for the
 SC> discrete Moog filters (Minimoog, 904a) seem to only use the negative
 SC> supply for the exponential convertor.  Can these be converted to run off
 SC> of a single ended supply?  Advantages, disadvantages?

There is nothing that really runs on real diffrential powersupply, if
you have single ended supply you can create any intermediate voltage
easy with simple tricks. With some swithcin you can get voltages above
the highest and belowe the lowest also, ever watched TV?

Actually, the Moog ladder has many intermediate voltages generated to
bias the transistors in the ladder.

Also, the input of the diode and Moog ladders is a pair of transistors
that is operating as the input stage of an diffrential amplifier with
variable gain. The first cap is similar to the compensation cap that
is usually available. The tricks done is just some uncommon
termination of this input, so just biasing the signal at about the
right level and the input end will adjust just fine like any op-amp.

 SC> Any advice welcome (answers, directions of where to look for answers,
 SC> etc.). 

One things to consider is that some cursuits may be more voltage
sensitive than others. This must be considered when running of
batteries since they inherently will drop voltage as you go.
It may be worth modifying some cursuits to become less voltage
dependent than they normally would be. Voltage references may be one
way to go.

 SC> I'm also interested in creating an MS-20 filter section clone that is
 SC> battery operated (I LOVE battery operated boxes - my little x0x boxes
 SC> are getting a lot of use nowadays, while I wait for the NM to arrive).
 SC> Any advice there?  It seems more straightforward - just using a voltage
 SC> divider to create a "virtual ground" that is 1/2 of the positive supply.
 SC> Any other tricks?

 SC> Thanks,

 SC> Sean Costello (who realizes how this post totally gives away his
 SC> ignorance of all things electronic.  I was reading "The Art of
 SC> Electronics" last night, and learned way too much that I should have
 SC> known before.  Apologies in advance for my ignorance, but I really do
 SC> want to learn this stuff.)

At least you are sitting there with a good book. Strongly recommended.
However, it takes time to fully consume the book so there is still
some usefull tricks to be found every now and then.

Don't use the cursuits with a crossed over light-bulb... :)

Cheers,
Magnus



From chordman at flash.net  Thu Jul 16 01:55:40 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Wed, 15 Jul 1998 23:55:40 GMT
Subject: More chua again
Message-ID: <35b24082.75553113@mail.lan>

I found this URL:

http://ftp.lpmi.u-nancy.fr/physique/chaos/oscillateur.html

That has a schematic with actual values for the components.  However,
the text is in French, and I can read only a small fraction of it.  (I
had French in the 3rd and 4th grades.  That was *many* years ago.)
Anyway, something else is that this circuit uses only one negative
resistance emulator.  Is this a mistake?

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From eduni at ucsd.edu  Thu Jul 16 02:25:58 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Wed, 15 Jul 1998 17:25:58 -0700 (PDT)
Subject: Nonlinear vs. chaotic
Message-ID: <199807160025.RAA28252@smtp.ucsd.edu>


>Nonlinear oscillators on the other hand can show interesting 
>behaviour like amplitude dependent harmonic structure (think of hard 
>stroked Rhodes reeds),
-speaking of which; has anyone used nonlinear transmission elements to make
the high-harmonic content of pulses or sawtooth waves more "ideal" in a
musical system? i'm doing a bunch of shockline stuff to that end at work,
but it doesn't have any immediate musical applications, so i wondered if
anyone had ever tried it.. or would cost be prohibitive?  

what i'd like to see is an audio-frequency pulse to soliton converter module.. 

Ethan




From pfperry at melbpc.org.au  Thu Jul 16 03:07:35 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 16 Jul 1998 11:07:35 +1000 (EST)
Subject: AW: motorised pots
Message-ID: <1.5.4.16.19961207174318.2cd75ca8@popa.melbpc.org.au>

At 09:17 AM 15/07/98 -0700, John Speth  wrote:
Isn't that why you usually see twinned pots?  --> one for your application
circuit and one for feedback to your controller for position information. 
....usually, yes. 

>Imagine a primo modular synth with motorized pots and LEDs for indicating
cable patching end points!!  You get the flexibility of programming a
modular with the ability to recall patches with the assistance of software.
That's my dream instrument (a la NASA budget)!
.....now you are talking! Although my own taste runs to a big patching
matrix with illuminated buttons..
press the button to connect/disconnect, with the button illuminating for 'on'..

paul perry in fantasyland, the happiest kingdom of them all.




From Puentstein at aol.com  Thu Jul 16 05:41:18 1998
From: Puentstein at aol.com (Puentstein at aol.com)
Date: Wed, 15 Jul 1998 23:41:18 EDT
Subject: "alternative controllers"
Message-ID: <d0307a16.35ad765f@aol.com>

In a message dated 98-07-14 16:37:40 EDT, gosd at lankaster.com writes:

<< hi again synth friends,
 i've been following the discussions on ldr's and finding it very
 interesting. i've just built a light controller board which i call the
 flying saucer because of it's shape. it has 6 CdS cells ( so far ) in
 the shape of a butterfly like this:
                     x                             x
                          x                   x
                        x                       x
 it's one of my favorite controllers i have built so far. i'd like to
 discuss these and other kinds of controllers (lately i've been very
 interested in ribbon controllers) with anyone interested.happy
 synthesizing y'all
 
 >>
There are probably several ways to make a "ribbon" controller. I wonder about
using an electrical, non-moving touch-plate strip (for triggering)  and a
(live) ultrasonic (or something exotic) distance measurer aimed parallel
immediately above the strip (For pitch).  Would it work?  For now I am just
working out the touch sensor circuit...              I also liked PPerry's
idea for using two voltages on a strip (for pitch), although I haven't figured
out how to do it, yet!  With that one, maybe something like an infrared
"burglar alarm" beam might be used to detect note triggers. ( I say "trigger"
because I'm designing for my analog mono synth rather than something midi. 

RS



From moxie at idonex.se  Thu Jul 16 11:17:43 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Thu, 16 Jul 1998 11:17:43 +0200 (MET DST)
Subject: More chua again
In-Reply-To: <35b24082.75553113@mail.lan> (chordman@flash.net)
Message-ID: <199807160917.LAA15709@jolt.idonex.se>

My quick take on translating the text:

==========================

Here's a diagram of a chaotic oscillator, also called "Chua
oscillator", used in the lab for some tests.

<schematic picture>

non-linear chaos generator oscillator.
ref...

This design use very classic parts, easy to reproduce. We suggest one
output and one control input. The 100K pot allow adjustment of the
"plage" of functioning. (probably some sort of range control,
considering where the pot is put :-> )

To listen to the sound of this oscillator: Click here, for the
chaotic mode.

Waveform graphs from the stable and the chaotic modes.

<stable pic>

Oscillation in the stable mode, the signal is harmonic

<chaos pic>

Oscillation in the chaotic mode.

Other pages on the net, A propos Chaos:

==========================

Mind you, it was some time since I had french, too, but I don't think
I'm too far off.
/Moxie (qui ne parle pas francois)




From H.J.vanderlinden at stud.far.ruu.nl  Thu Jul 16 15:14:02 1998
From: H.J.vanderlinden at stud.far.ruu.nl (Heiko van der Linden)
Date: Thu, 16 Jul 1998 15:14:02 +0200
Subject: EPROM PROGRAMMER
Message-ID: <35ADFC9A.4A63FB0F@stud.far.ruu.nl>

Hi,
I,m currently working with a microprocessor development system and waas
wondering if there are any freeware eprom programmer resources
(pcb-layout+software)
And I was also wondering if someone has the assembler for th tb-303
mp-650d controller or any other assembler code that performs about the
same tasks as the tb-303.
thanks




From pfperry at melbpc.org.au  Thu Jul 16 15:33:50 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 16 Jul 1998 23:33:50 +1000 (EST)
Subject: Nonlinear vs. chaotic
Message-ID: <1.5.4.16.19961208060935.0e972da2@popa.melbpc.org.au>

At 05:25 PM 15/07/98 -0700, >Ethan Duni wrote:

>-speaking of which; has anyone used nonlinear transmission elements to make
>the high-harmonic content of pulses or sawtooth waves more "ideal" in a
>musical system? i'm doing a bunch of shockline stuff to that end at work,
>but it doesn't have any immediate musical applications, 

I am looking for a physical (or electronic! I'm not fussy!) method to delay an
audio signal, with the delay being strongly frequency dependant, so the elements
of a noise pulse will spread out timewise... I believe a corrugated tube will
do this over a narrow frequency range, but I need a full bandwidth audio
solution...

paul perry melbourne australia




From don at till.com  Thu Jul 16 17:08:47 1998
From: don at till.com (Don Tillman)
Date: Thu, 16 Jul 1998 08:08:47 -0700 (PDT)
Subject: AW: tubes, transistors......
In-Reply-To: <3.0.5.32.19980714113241.007b3be0@192.168.210.18>
	(b.layer@vikingelectronics.com)
Message-ID: <199807161508.IAA16126@shell9.ba.best.com>

   Date: Tue, 14 Jul 1998 11:32:41 -0500
   From: "Bill Layer" <b.layer at vikingelectronics.com>

   Juergen's comments have raised a deep and perplexing Zen-type issue, that
   is: What is the actual sound of an electronic instrument? The design or the
   parts or the patch or???? 

   A logically related question is: what is the sound of an instrument, if not
   the sum of it's fundamental and distortion products, irrespective of the
   source of that distortion? How is it defined? How should we define it?

These questions are in an extremely reductionist context, which is
highly unzenlike.

The zen student learns that breaking things up into little bits and
asking which is the heart is not the path to enlightenment.

  -- Don



From b.layer at vikingelectronics.com  Thu Jul 16 17:42:54 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 16 Jul 1998 10:42:54 -0500
Subject: AW: tubes, transistors......
In-Reply-To: <199807161508.IAA16126@shell9.ba.best.com>
References: <3.0.5.32.19980714113241.007b3be0@192.168.210.18>
Message-ID: <3.0.5.32.19980716104254.007a1a60@192.168.210.18>

>
>These questions are in an extremely reductionist context, which is
>highly unzenlike.
>
>The zen student learns that breaking things up into little bits and
>asking which is the heart is not the path to enlightenment.

Pardon my profane interpretation. Seriously though, in no way would I
suggest that I know the first thing about true Zen. It's all Lay-ity here!

I think my post was further off topic than I had realized. Time this thread
is cut...


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From costello at seanet.com  Thu Jul 16 17:55:23 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 08:55:23 -0700
Subject: Nonlinear vs. chaotic
References: <1.5.4.16.19961208060935.0e972da2@popa.melbpc.org.au>
Message-ID: <35AE226B.C0DFF83C@seanet.com>

Paul Perry wrote:

> I am looking for a physical (or electronic! I'm not fussy!) method to delay an
> audio signal, with the delay being strongly frequency dependant, so the elements
> of a noise pulse will spread out timewise... I believe a corrugated tube will
> do this over a narrow frequency range, but I need a full bandwidth audio
> solution...

I recall reading somewhere that several allpass filter stages connected
in series will do this, I believe. By "several" I mean "several hundred"
or some absurd number.  I'll try to find the source later on today.

Sean Costello





From costello at seanet.com  Thu Jul 16 19:02:05 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 10:02:05 -0700
Subject: Serge & Buchla Schematics available online
Message-ID: <35AE320D.6C789BAE@seanet.com>

Hi all:

Music Machines now has a few select Serge & Buchla schematics.  Go to
http://www.hyperreal.org/music/machines/schematics.html and check out
the schematics for the Buchla Lopass Gate, the Serge TKB, and the Serge
Waveshaper.

Later,

Sean Costello



From costello at seanet.com  Thu Jul 16 19:12:04 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 10:12:04 -0700
Subject: Steiner-Parker?  Other diode filters?
Message-ID: <35AE3464.BAC659C9@seanet.com>

Hi all:

Does anyone out there have any Steiner-Parker schematics?  The
description of these synths sounds interesting.  In particular, anyone
know how the filters work?

On a related note, Nyle Steiner has an article in Electronic Design #25,
from Dec. 6, 1974, about a "simple low-pass, band-pass, high-pass
structure using dynamic resistance of diodes."  Time to head to the
University of Washington again to check out the Engineering Library.

On a less related note, I went to the UW Engineering Library yesterday
to look up info on nonlinear oscillators in music.  Several interesting
papers came out of one N.H. Fletcher, from Australia (lots of cool stuff
about nonlinear mechanisms in gongs and cymbals).

On a more related note, does anyone else out there know of synth VCF's
that used diodes as the control voltage element (as opposed to the
transistors in the Moog design)?  I know of only a few:

EMS VCS3/Synthi
Roland TB-303
Korg MS-50 (these three can be seen at http://www.seanet.com/~costello)
Practical Electronics Minisonic

What other synths used diode filters?  I suspect the Steiner-Parker
synths used these (perhaps in a state-variable configuration). Did some
of the older Rolands use diode ladder filters?  Didn't PAiA use diodes
in some of their filters?

Once again, any and all info appreciated.  You folks have helped me a
lot lately.

Thanks,

Sean Costello



From costello at seanet.com  Thu Jul 16 19:13:47 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 10:13:47 -0700
Subject: EMS VCS3 Ring Modulator - how does it work?
Message-ID: <35AE34CB.815CF22F@seanet.com>

Hi everybody:

Anyone know what is inside the VCS3 ring modulator?  I've never seen a
circuit.  Is it a transformer based design, or discrete transistors, or
a 1496 design, or...?

Thanks,

Sean Costello



From jamos at technotoys.com  Thu Jul 16 23:07:07 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Thu, 16 Jul 1998 14:07:07 -0700
Subject: Serge Waveshaper schemos on Music Machines
Message-ID: <199807161407070880.00105282@mail.proaxis.com>

Coupla questions for anyone who has seen the Serge schematic Sean Costello
located at Music Machines, for anyone who cares to hazard some guesses.

1) Which waveshaper is it? It looks closest to #2 based on the number of
ins and outs, but it's not a perfect match.

2) Anyone know which input is which?

3) What's the polarity of the op-mp - which terminal is +?

4) Why use an LM3900 in this circuit, rather than a TL-074? 

Thankee-sai,



Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com




From urekar.m at EUnet.yu  Thu Jul 16 23:32:16 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Thu, 16 Jul 1998 23:32:16 +0200
Subject: EMS VCS3 Ring Modulator - how does it work?
References: <35AE34CB.815CF22F@seanet.com>
Message-ID: <35AE7160.58CF@eunet.yu>

Sean Costello wrote:
> 
> Hi everybody:
> 
> Anyone know what is inside the VCS3 ring modulator?  I've never seen a
> circuit.  Is it a transformer based design, or discrete transistors, or
> a 1496 design, or...?

It uses IC TAB 101 ,2c764 tranny pair and few discrete transistors.
TAB is four (matched ?) transistors but note with schematics that
in later models it has been replaced with 2c746,early ones with
matched bc 169c (?).I guess you can use 3046 instead. 
Schematic looks like the one on tomg's site but with some transistor
input stages and current source and few trimers more,
9 npns and one pnp in all.
Reminds me on discrete 1496 rm if memory serves me.





marjan



From urekar.m at EUnet.yu  Thu Jul 16 23:44:01 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Thu, 16 Jul 1998 23:44:01 +0200
Subject: Steiner-Parker?  Other diode filters?
References: <35AE3464.BAC659C9@seanet.com>
Message-ID: <35AE7421.4D42@eunet.yu>

> On a more related note, does anyone else out there know of synth VCF's
> that used diodes as the control voltage element (as opposed to the
> transistors in the Moog design)?  I know of only a few:
> 
> EMS VCS3/Synthi
> Roland TB-303
> Korg MS-50 (these three can be seen at http://www.seanet.com/~costello)
> Practical Electronics Minisonic
> 

there's one on moo site 
http://www.ecr.mu.oz.au/~ndf/synth/archive/main.html

there were some diodes in transcendent 2000 vcf but it contains 
ca 3080 also (diodes in bridge config ?) - check anders 
spontons site


marjan



From costello at seanet.com  Thu Jul 16 23:52:22 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 14:52:22 -0700
Subject: Steiner-Parker?  Other diode filters?
References: <35AE3464.BAC659C9@seanet.com> <35AE7421.4D42@eunet.yu>
Message-ID: <35AE7616.74625C36@seanet.com>

<<>> wrote:
> 
> > On a more related note, does anyone else out there know of synth VCF's
> > that used diodes as the control voltage element (as opposed to the
> > transistors in the Moog design)?  I know of only a few:
> >
> > EMS VCS3/Synthi
> > Roland TB-303
> > Korg MS-50 (these three can be seen at http://www.seanet.com/~costello)
> > Practical Electronics Minisonic
> >
> 
> there's one on moo site
> http://www.ecr.mu.oz.au/~ndf/synth/archive/main.html

This is the same schematic as on my site, but redrawn.  It is much
higher quality than the schematic I have posted.

Sean Costello



From magnus at analogue.org  Fri Jul 17 00:17:56 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 17 Jul 1998 00:17:56 +0200
Subject: Nonlinear vs. chaotic
In-Reply-To: Your message of "Thu, 16 Jul 1998 23:33:50 +1000 (EST)"
References: <1.5.4.16.19961208060935.0e972da2@popa.melbpc.org.au>
Message-ID: <199807162217.AAA26259@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

Hi Paul!

 PP> At 05:25 PM 15/07/98 -0700, >Ethan Duni wrote:
 >> -speaking of which; has anyone used nonlinear transmission elements to make
 >> the high-harmonic content of pulses or sawtooth waves more "ideal" in a
 >> musical system? i'm doing a bunch of shockline stuff to that end at work,
 >> but it doesn't have any immediate musical applications, 

 PP> I am looking for a physical (or electronic! I'm not fussy!) method to delay an
 PP> audio signal, with the delay being strongly frequency dependant, so the elements
 PP> of a noise pulse will spread out timewise... I believe a corrugated tube will
 PP> do this over a narrow frequency range, but I need a full bandwidth audio
 PP> solution...

If you want to do this with audio you are looking into using some kind
of diffusor setup. An diffusor will partly dampening and partly
reflect the wave. The reflected wave will be spread out in time by the
simple fact that you got a lot of reflecting surfaces. There are many
ways to set such a thing up and I can direct your attention to a
number of books taking up the subject among others.

There is of course ways to do it electrically, a reverb will have a
few distinct early reflections and then follows a long tail of
diffusion. A serious digital reverb let you tweak the individual
parameters at your taste. I would recommend a tweak session over a
Lexicon reverb, PCM-70 or LXP-15 or something. This is not very DIYish
but to get the effect you want you might still need to tweak it into
the place you want.

Otherwise will your discussion also makes me thing of dispersion (such
as you have in microwave fields and optic fibers), if you get a line
properly you can get the dispersion work for you in this case. This
can be done in many ways, but the general principle is that you have
various speeds of wavepropagations and the signal is being effected by
all of these.

I don't think it pure analog design will provide a enougth complex
obstruction to get the wished effect, but with some nonlinear stuff
like BBDs it could be possible to obstruct it a bit...

Could any of these methods help?

Cheers,
Magnus




From hdan at charybdis.com  Fri Jul 17 00:28:16 1998
From: hdan at charybdis.com (Dan Higdon)
Date: Thu, 16 Jul 1998 17:28:16 -0500
Subject: Serge Waveshaper schemos on Music Machines
Message-ID: <01bdb109$072aa820$352ccfcf@ares.charybdis.com>

From: Jim Johnson <jamos at technotoys.com>
>1) Which waveshaper is it? It looks closest to #2 based on the number of
>ins and outs, but it's not a perfect match.

I don't know - I haven't breadboarded this one yet, either.  The LM3900
is a quad, so I'd guess it's the other waveshaper - the one with multiple
identical sections (dang - I don't have my Serge catalog handy).  Maybe
a VC wave->square converter?

>2) Anyone know which input is which?

Nope.

>3) What's the polarity of the op-amp - which terminal is +?

3rd strike - but I'm not quite out yet.  :-)

>4) Why use an LM3900 in this circuit, rather than a TL-074? 

That one I *do* know - the LM3900 is a "Norton Amplifier", and as
such has some magical properties.  :-)  Seriously, the circuit only
works *because* it's an LM3900.  Mr. Serge patented a couple
of designs based on this chip.  If you look at the data sheet for it,
you'll also notice the Serge VC pulse divider.

----------------------------------------
hdan at charybdis.com
"Trust not the monkey, nor his clever schemes" - hdan




From cyborg0 at GlobalEyes.net  Fri Jul 17 00:59:18 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 16 Jul 1998 17:59:18 -0500
Subject: EPROM PROGRAMMER
References: <35ADFC9A.4A63FB0F@stud.far.ruu.nl>
Message-ID: <35AE85C6.415305C4@globaleyes.net>

Heiko van der Linden wrote:
> 
> Hi,
> I,m currently working with a microprocessor development system and waas
> wondering if there are any freeware eprom programmer resources
> (pcb-layout+software)
> And I was also wondering if someone has the assembler for th tb-303
> mp-650d controller or any other assembler code that performs about the
> same tasks as the tb-303.
> thanks
Well, actually, you could prolly very easily construct the flowchart for
the tb-303 esp since the original processor in it is about as powerful
as the one in your wristwatch!
	The rom is read-destructive (why, i dont know) so you CANT get the
original assembler code.. Besides it would prolly be worthless when
trying to apply it to todays uPs..

	If you are going to do this with a modern processor, you need to
approach the system as a whole, since some things such as the static
rams can be removed completely due to todays integration level ie a LOT
of chips include far more memory onboard. Heck, you might even be able
to use a basic stamp rather than an actual assembler driven processor.
That would prolly get you up and running faster. The basic stamp kits
with the programmers and everything run only about 100 dollars..so cheap
you dont need it to be free..

rob



From magnus at analogue.org  Fri Jul 17 01:22:29 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 17 Jul 1998 01:22:29 +0200
Subject: EMS VCS3 Ring Modulator - how does it work?
In-Reply-To: Your message of "Thu, 16 Jul 1998 10:13:47 -0700"
References: <35AE34CB.815CF22F@seanet.com>
Message-ID: <199807162322.BAA26776@piraya.electrum.kth.se>

>>>>> "SC" == Sean Costello <costello at seanet.com> writes:

 SC> Hi everybody:

Hi Sean!

 SC> Anyone know what is inside the VCS3 ring modulator?  I've never seen a
 SC> circuit.  Is it a transformer based design, or discrete transistors, or
 SC> a 1496 design, or...?

It is a design built around a TAB 101 IC which holds 4 transistors
connected together to form a Gilbert-cell. The design lacks the arctan
diodes, so it will have unlinearities as you should expect from any
other of noncompensated designs. I notice that there is some cross
feeding of input to to suppression.

In most reagards this should be similar to a 1495 design or something.
Maybe Juergen could comment on that?

Cheers,
Magnus



From costello at seanet.com  Fri Jul 17 01:44:58 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 16 Jul 1998 16:44:58 -0700
Subject: Serge Waveshaper schemos on Music Machines
References: <199807161407070880.00105282@mail.proaxis.com>
Message-ID: <35AE907A.223C0C5F@seanet.com>

Jim Johnson wrote:
> 
> Coupla questions for anyone who has seen the Serge schematic Sean Costello
> located at Music Machines, for anyone who cares to hazard some guesses.
> 
> 1) Which waveshaper is it? It looks closest to #2 based on the number of
> ins and outs, but it's not a perfect match.

It is actually the variable sawtooth-to-sine waveshaper from the Triple
Waveshaper module, and the old oscillator designs.  Unfortunately, this
isn't the Wave Multiplier circuit - but I feel that someone smart can
combine this schematic with the Serge Tcherepnin patent to figure out at
least part of the Wavemultipler circuit.  The VC full-wave rectifier
should be a simple adaptation of this circuit.  I breadboarded a single
VC rectifier stage a while back, and it sounded really nice while
sweeping the control voltage.
 
> 2) Anyone know which input is which?

The middle input is for the (sawtooth) input, the other two inputs are
for the control voltages.

> 3) What's the polarity of the op-mp - which terminal is +?

Doh!  I forgot to put that in when I relabeled the circuit.  I'll look
it up on my original diagram when I can find it.  My guess is that the
top terminal is (-) and the bottom terminal is (+), since the (+)
terminal is where the control voltage is applied in other LM3900
applications (the VCA design in Electronotes #41, for example, which is
a modification of the VCA in the National Semiconductor application note
AN-72).

> 4) Why use an LM3900 in this circuit, rather than a TL-074?

As Dan Higdon just wrote, the LM3900 is the heart of the circuit.  Go to
http://www.patents.ibm.com, select "Search" and do a search for
Inventor:Serge AND Inventor:Tcherepnin.  One of his 2 patents covers the
really super keen techniques Serge came up with for the LM3900.  Paia
also used the LM3900 extensively in circuitry.

Later,

Sean Costello



From sidlar at loon.norlink.net  Fri Jul 17 01:55:07 1998
From: sidlar at loon.norlink.net (Frank Lemieux)
Date: Thu, 16 Jul 1998 19:55:07 -0400
Subject: motorised pots and other controls
In-Reply-To: <01BDAFD1.5B1D1460@johns.oei.com>
Message-ID: <3.0.2.32.19980716195507.008aada0@mail.norlink.net>

>Imagine a primo modular synth with motorized pots and LEDs for indicating
cable patching end points!!  You get the flexibility of programming a
modular with the ability to recall patches with the assistance of software.
 That's my dream instrument (a la NASA budget)!

Last week I actually had a dream where my ideal synth appeared to me...  It
may have been heat-stroke from being outside at a music festival for days,
but it was very clear... I saw flat black (ala star trek next generation)
panelling lit from underneath to show the labelling when required, and
motorized sliders that moved when I changed patches...  I've always liked
sliders...  In my dream, I saw all the schematics, though they are beyond
my means to recreate...  I even got a look at the micro controller code
that ran it all...  It seemed very efficient the way it was put together,
its switching matrices making modular mapping simple and easy, and allowing
powerful self-diagnostic processes...  I only hope its as easy in real life
as it was there!

I've taken it as a sign...  I'm designing slowly, as I learn how...  The
relevant question in all this is are motorized sliders available?  I'm
gonna build it even if it kills me. :P

Has anyone here worked on capacitance sensors?  I'm trying to figure out
how those star-trek like panels worked :) Inductance, maybe? hmm...






From brucejd at interlog.com  Fri Jul 17 02:50:06 1998
From: brucejd at interlog.com (bruce duncan)
Date: Thu, 16 Jul 1998 20:50:06 -0400 (EDT)
Subject: VCS3 Filter Cap values
Message-ID: <199807170050.UAA03689@smtp.interlog.com>

Hi All,

I am in the process of breadboarding the VCS3 filter and was wondering if
anyone knows what value 47Kpf or 10Kpf is as indicated on the schemos that
are out there? 
Is it 47000pf or 47 pf. I have seen plenty of ceramic caps labeled
47K,82K,22K etc and they are just 47,82 and 22 pf etc.
respectively. Anyone know for sure. Other cap values on the schems are in
micro farrads so why not indicate 47Kpf as
.047mfd ? 
Cursed British and their non standard cap values!

Thanks
Bruce
 






From eleckie at cochlear.com.au  Fri Jul 17 02:59:21 1998
From: eleckie at cochlear.com.au (Edward Leckie)
Date: Fri, 17 Jul 98 10:59:21 +1000
Subject: AW: motorised pots
Message-ID: <9807179006.AA900637361@ccgate.cochlear.com.au>


If you wanted a simple connection couldn't you use a Cross-point switch, with
buttons for X and Y. Or using with a micro, use a fast switching technique with
variable pulsewidth to generate an effective resistance and hence have a
variable attenuating programmable matrix. 

Ed.



____________________Reply Separator____________________
Subject:    Re: AW: motorised pots
Author: Paul Perry <pfperry at melbpc.org.au>
Date:       16/07/98 11:07

At 09:17 AM 15/07/98 -0700, John Speth  wrote:
Isn't that why you usually see twinned pots?  --> one for your application
circuit and one for feedback to your controller for position information. 
....usually, yes. 

>Imagine a primo modular synth with motorized pots and LEDs for indicating
cable patching end points!!  You get the flexibility of programming a
modular with the ability to recall patches with the assistance of software.
That's my dream instrument (a la NASA budget)!
.....now you are talking! Although my own taste runs to a big patching
matrix with illuminated buttons..
press the button to connect/disconnect, with the button illuminating for 'on'..

paul perry in fantasyland, the happiest kingdom of them all.







From jamos at technotoys.com  Fri Jul 17 04:39:52 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Thu, 16 Jul 1998 19:39:52 -0700
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <35AE907A.223C0C5F@seanet.com>
References: <199807161407070880.00105282@mail.proaxis.com>
 <35AE907A.223C0C5F@seanet.com>
Message-ID: <199807161939520640.00F257A9@mail.proaxis.com>

Thanks for the clarifications, Sean. I had forgotten about the Triple
Waveshaper - it's been a while since I drooled on my Serge catalog.

But as in all scientific endeavours, the best answers only lead to more
questions!

- Is that really a unipolar supply? Is that standard for Serge stuff? In
that case, shouldn't the output be capacitively coupled?

- Does the diode next to the inputs of the op-amp connect to to both
inputs, or just the upper (-) pin? 

- What is the difference between the two CV inputs?

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com



*********** REPLY SEPARATOR ***********

On 7/16/98, at 4:44 PM, Sean Costello  wrote: 

>Jim Johnson wrote:
>> 
>> Coupla questions for anyone who has seen the Serge schematic Sean
Costello
>> located at Music Machines, for anyone who cares to hazard some guesses.
>> 
>> 1) Which waveshaper is it? It looks closest to #2 based on the number of
>> ins and outs, but it's not a perfect match.
>
>It is actually the variable sawtooth-to-sine waveshaper from the Triple
>Waveshaper module, and the old oscillator designs.  Unfortunately, this
>isn't the Wave Multiplier circuit - but I feel that someone smart can
>combine this schematic with the Serge Tcherepnin patent to figure out at
>least part of the Wavemultipler circuit.  The VC full-wave rectifier
>should be a simple adaptation of this circuit.  I breadboarded a single
>VC rectifier stage a while back, and it sounded really nice while
>sweeping the control voltage.
> 
>> 2) Anyone know which input is which?
>
>The middle input is for the (sawtooth) input, the other two inputs are
>for the control voltages.
>
>> 3) What's the polarity of the op-mp - which terminal is +?
>
>Doh!  I forgot to put that in when I relabeled the circuit.  I'll look
>it up on my original diagram when I can find it.  My guess is that the
>top terminal is (-) and the bottom terminal is (+), since the (+)
>terminal is where the control voltage is applied in other LM3900
>applications (the VCA design in Electronotes #41, for example, which is
>a modification of the VCA in the National Semiconductor application note
>AN-72).
>
>> 4) Why use an LM3900 in this circuit, rather than a TL-074?
>
>As Dan Higdon just wrote, the LM3900 is the heart of the circuit.  Go to
>http://www.patents.ibm.com, select "Search" and do a search for
>Inventor:Serge AND Inventor:Tcherepnin.  One of his 2 patents covers the
>really super keen techniques Serge came up with for the LM3900.  Paia
>also used the LM3900 extensively in circuitry.
>
>Later,
>
>Sean Costello



From cyborg0 at GlobalEyes.net  Fri Jul 17 06:17:07 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 16 Jul 1998 23:17:07 -0500
Subject: other controls aka capacitive plates 
References: <3.0.2.32.19980716195507.008aada0@mail.norlink.net>
Message-ID: <35AED043.ABC094FF@globaleyes.net>

Frank Lemieux wrote:

> Has anyone here worked on capacitance sensors?  I'm trying to figure out
> how those star-trek like panels worked :) Inductance, maybe? hmm...

Well, yeah.. a Theremin works on this principal..
Basically, you have a waveform traveling through the touch pad
(capacitance)..The output of this goes into a phase comparator.Your body
parts invoke a change in capacitance .If the "after" wave (the one going
through the plate) is too far out of phase with the "before", or input
wave, then you can have the resultant correction voltage trigger
something. Heck, you prolly could use a PLL to do the whole little
deal..
What would be REALLY cool is to have it so that it knows exactly how FAR
out of phase it is..I know with a PLL, it generates a correction voltage
in response to exactly how far out of phase it is as long as the phase
difference is within the capture range..it would be cool if you could
have the capture range large enough to give a big enough voltage
difference to generate other types of control data.
Maybe put a piezo under each plate to simulate pressure or impact and
route this to a VCA..

John Simonton at paia loves these things, or so it seems...
go to the paia website, he seems really into this sort of control..
rob



From pfperry at melbpc.org.au  Fri Jul 17 10:49:05 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 17 Jul 1998 18:49:05 +1000 (EST)
Subject: audio delay dispersion
Message-ID: <1.5.4.16.19961209012449.300fcbe6@popa.melbpc.org.au>

At 10:45 AM 16/07/98 -0400,  Eli Brandt wrote:

>D*g*t*l dispersion: I've used a chain of allpass filters (simpler),
>and a filterbank with a bunch of delays (non-ideal, more tweakable).
>Both would be pretty hairy in analogue, I guess.
>Mechanical dispersion: well, remember those audio-transmission delay
>boxes?  Do one in wire instead of air-column.  (Stiffness makes
>higher frequencies move faster.)  Too bad about that speed of sound...
I guess we could fill the column with depleted uranium hexaflouride..
seriously though, how many filters did you use & was it uesful?
Would it be worth adding delay to N vocoder channels?

paul perry melb aust




From pfperry at melbpc.org.au  Fri Jul 17 10:49:31 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 17 Jul 1998 18:49:31 +1000 (EST)
Subject: EMS VCS3 Ring Modulator - how does it work?
Message-ID: <1.5.4.16.19961209012515.300fdab4@popa.melbpc.org.au>

At 01:22 AM 17/07/98 +0200, Magnus Danielson  wrote:

>In most reagards this should be similar to a 1495 design or something.

curiously enough, my VCS3 broke down and it was repaired by replacing
the ring mod ckt with one bsed on a MC1495.....
this was befor I got into soldering myself..

paul perry melbourne australia




From brun at bart.nl  Fri Jul 17 11:52:58 1998
From: brun at bart.nl (Jeroen Bruintjes)
Date: Fri, 17 Jul 1998 11:52:58 +0200
Subject: Oberheim OB-X
Message-ID: <199807170953.LAA13625@smtp2.xs4all.nl>

Hi people,

I've been offered to buy an Oberheim OB-X for quite a lot of cash. Now, I do 
know this machine predates the OB-Xa and differs from it in several details, 
but I'd like to know if you know some more details? In other words: tell me 
everything you know about this machine :)

Bye,

Jeroen



-> Brun, met een dakje op de u.



From Juergen.Haible at nbgm.siemens.de  Fri Jul 17 12:27:06 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 17 Jul 1998 12:27:06 +0200
Subject: AW: EMS VCS3 Ring Modulator - how does it work?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58285455C@nbgm336a.nbgm.siemens.de>


	> Maybe Juergen could comment on that?

Almost everything was said already.

The circuit is very similar to the standard AC coupled 1496 application,
and I have used a 1496 in my clone.
Bias currents for the VCS3 are far smaller than suggested for the 1496,
but the 1496 works with these values, too.
The two additional trimmers are used to cancel bleedthrough at the
*double* carrier and modulator frequency. (In addition to the usual trimmers
that provide carrier and modulator suppression.) I'm not sure if this was
needed
to compensate unsymmetries of the modulator, or crosstalk from the matrix.
You can implement these additional trimmers in a 1496 circuit, too.
The output is single ended, i.e. not the usual differential amp after the
gilbert
cell. Only a single transistor to amplify one of the two collector paths. 
Works fine. May be chosen because of economy, and may affect PSR.
If you look at the EMS diagram and the 1496's internal circuit, it's clear
how to to the replacement. Keep the dc bias levels from the original, and
everything is fine. The bias current generation, and the bias current offset
for the two legs is different, but it should make no difference. Just head
for
the same overall current thru the gilbert cell.

JH.




From Juergen.Haible at nbgm.siemens.de  Fri Jul 17 12:37:11 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 17 Jul 1998 12:37:11 +0200
Subject: AW: VCS3 Filter Cap values
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58285457A@nbgm336a.nbgm.siemens.de>

	>I am in the process of breadboarding the VCS3 filter and was
wondering if
	>anyone knows what value 47Kpf or 10Kpf is as indicated on the
schemos that
	>are out there? 

Just multiply the factors. k=1e3, p=1e-12, kp=n=1e-9.
As curious as it may look, it's even mathematically 
correct. (;->)

BTW: The filter schemos show a 10u capacitor across the
CV input ( C31, parallel to the 1k lower divider leg).
This will slow down modulation transients. S&H sounds
like using a portamento, for example. I have no idea if
this is an error in the schemos or if it's actually inside the 
VCS3, but I've cut it out on my clone yesterday, and it sounds
much better now.

JH



From sky36919 at skynet.be  Fri Jul 17 12:46:54 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Fri, 17 Jul 1998 12:46:54 +0200
Subject: DSP: ADI-Dream?
In-Reply-To: <memo.598704@cix.compulink.co.uk>
Message-ID: <199807171047.MAA09344@papagena.skynet.be>

Hi Martin and List !

The ADI csound development kit is priced usd 1000 :)
(pci board with a slew of ported software plus the csound book)

This does not include SHARC development software, available "at a 
small fee" .

A daughterboard is planned with digital i/o .

The target audience for this card are "sound developers" but the 
blurb goes on to say that they want to license the technology (and 
extended csound) to machine or card manufacturers .

The cards are "hand-build" at ADI .

The above i remember from a post (or several) to the csound mailing 
list .

This was nov dec 97 .

There is still no release date for the book .

On the docs i've seen from creamware, there was no explicit talk of 
csound, but i've not checked recently .  The new pulsar, i heard of 
on electronica, could well be the i/o board with 4 sharc's the 
original Scope blurb went on about .

I'd be surprised though, that the virtual modular Creamware 
mentions, is csound .  For this one, my money is on Waldorf :)
Let's face it, they have to do a lot better than the Nord Modular, 
and that is a very tall order ;-)

Csound, batch processing background and all, has big problems with 
latency and midi i/o  .  People are working on it, but imho the basic 
structure is not very well suited for real time operation . It is 
also not easy to run in multiprocessor environments (but it has been 
done) and afaik, has not been mentioned in excsound context .

Good luck :)

Keep 'em oscillating :)

Hugo (still looking for info on PressNPeel laserprinters :)
=



From Juergen.Haible at nbgm.siemens.de  Fri Jul 17 12:51:21 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 17 Jul 1998 12:51:21 +0200
Subject: AW: Steiner-Parker?  Other diode filters?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5828545C4@nbgm336a.nbgm.siemens.de>

	>On a more related note, does anyone else out there know of synth
VCF's
	>that used diodes as the control voltage element (as opposed to the
	>transistors in the Moog design)?  I know of only a few:
	>
	>EMS VCS3/Synthi
	>Roland TB-303
	>Korg MS-50 (these three can be seen at
http://www.seanet.com/~costello)
	>Practical Electronics Minisonic
	>
	>What other synths used diode filters?  I suspect the Steiner-Parker
	>synths used these (perhaps in a state-variable configuration). Did
some
	>of the older Rolands use diode ladder filters?  Didn't PAiA use
diodes
	>in some of their filters?

Roland SH-5, if memory serves.
And I wouldn't be surprised if the "Korg-35" IC, that was widely used
in many Korg synths, uses a diode ring, too. I really do not know,
so don't create a myth, I just think that it would make sense.

JH.



From shudder at optusnet.com.au  Fri Jul 17 14:54:18 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Fri, 17 Jul 1998 22:54:18 +1000
Subject: [sdiy] Soldering Saftey Tip Reminder
Message-ID: <004801bdb182$05bed820$89288ec6@dialup.mpx.com.au>


Hi Jim,

>    This is mostly for the people here who are new to soldering....
>
>    Wear those saftey glasses while soldering!

Too late for me. 2 days ago I copped a big glob of well heated solder in the
corner of my eye. My completely wild reaction prevented much of the pain,
the injuries resulting from the REACTION were worse :) Glasses will be worn
from now on.
Regards,
Sean




From urekar.m at EUnet.yu  Fri Jul 17 16:01:43 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Fri, 17 Jul 1998 16:01:43 +0200
Subject: AW: VCS3 Filter Cap values
References: <1BF5E20E0C4DD111BBAB00805FE2D58285457A@nbgm336a.nbgm.siemens.de>
Message-ID: <35AF5923.7055@eunet.yu>

Haible Juergen wrote:

> BTW: The filter schemos show a 10u capacitor across the
> CV input ( C31, parallel to the 1k lower divider leg).
> This will slow down modulation transients. S&H sounds
> like using a portamento, for example. I have no idea if
> this is an error in the schemos or if it's actually inside the
> VCS3, but I've cut it out on my clone yesterday, and it sounds
> much better now.


It's mistake in the schematic,lower leg of cap should go down
to -9V rail.If you look to it ,there's one C40 10uF 16 V 
filter cap between +9V and gnd rail,but there's no for the 
-9/gnd.Even polarisation is (+) to gnd ,so (-) should go
to - (and cutoff in can go above 0V).



marjan



From Juergen.Haible at nbgm.siemens.de  Fri Jul 17 16:21:17 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 17 Jul 1998 16:21:17 +0200
Subject: AW: AW: VCS3 Filter Cap values
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582859BEE@nbgm336a.nbgm.siemens.de>

	>It's mistake in the schematic,lower leg of cap should go down
	>to -9V rail.If you look to it ,there's one C40 10uF 16 V 
	>filter cap between +9V and gnd rail,but there's no for the 
	>-9/gnd.Even polarisation is (+) to gnd ,so (-) should go
	>to - (and cutoff in can go above 0V).

Hi Marjan,

thanks for the clarification - this makes perfect sense.

BTW, do you have corrected schemos, or did you check
it on the real thing? Do you know about more errors
(other than the obviously inverted transistors on Graham's
site) ?

JH.





From PapaJ59871 at aol.com  Fri Jul 17 18:26:35 1998
From: PapaJ59871 at aol.com (PapaJ59871 at aol.com)
Date: Fri, 17 Jul 1998 12:26:35 EDT
Subject: motorised pots and other controls
Message-ID: <59658d3c.35af7b3d@aol.com>

In a message dated 98-07-16 20:07:06 EDT, sidlar at loon.norlink.net writes:

<< Has anyone here worked on capacitance sensors?  I'm trying to figure out
 how those star-trek like panels worked :) Inductance, maybe? hmm... >>

There's some stuff on the capacitive touch switches at
http://www.paia.com/touchsw.htm .

-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 b.layer at vikingelectronics.com  Fri Jul 17 18:43:11 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 17 Jul 1998 11:43:11 -0500
Subject: new email addr
Message-ID: <3.0.5.32.19980717114311.007a4100@192.168.210.18>

All,

b.layer at vikingelectronics.com = blayer at uswest.net (at home)



------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From eli at gs160.sp.cs.cmu.edu  Fri Jul 17 18:48:36 1998
From: eli at gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Fri, 17 Jul 1998 12:48:36 -0400 (EDT)
Subject: audio delay dispersion
In-Reply-To: <1.5.4.16.19961209012449.300fcbe6@popa.melbpc.org.au> from "Paul Perry" at Jul 17, 98 06:49:05 pm
Message-ID: <199807171649.SAA04895@mailhost.bpa.nl>

Paul Perry wrote:
> I guess we could fill the column with depleted uranium hexaflouride..
> seriously though, how many filters did you use & was it uesful?

About a dozen, as I recall, but they each included from maybe 10 to
100 ms of digital delay.  With an analog design, I think if you want
say 100 ms of delay at 10kHz (for dispersion something less than
that), that's 1000 cycles or 360,000 degrees or 2000 poles.

> Would it be worth adding delay to N vocoder channels?

Well, it did sound pretty cool.  (I ought to dig it up and try that
multi-band chorus scheme.)  How much work it would be I have no idea;
it's way out of my league.

-- 
     Eli Brandt  |  eli+ at cs.cmu.edu  |  http://www.cs.cmu.edu/~eli/



From PapaJ59871 at aol.com  Fri Jul 17 19:59:47 1998
From: PapaJ59871 at aol.com (PapaJ59871 at aol.com)
Date: Fri, 17 Jul 1998 13:59:47 EDT
Subject: AW: Steiner-Parker?  Other diode filters?
Message-ID: <b6de5be.35af9114@aol.com>

<< Didn't PAiA use  diodes in some of their filters? >>

The original 2720 filters (2720-3L and 2720-3B) used diodes. There was also a
panning tremolo called the Ping Pong that used diodes as the control elements.

Long ago and in a galaxy far, far away :-)

-JS



From costello at seanet.com  Fri Jul 17 20:46:16 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 17 Jul 1998 11:46:16 -0700
Subject: Steiner-Parker filter schematics, anyone?
Message-ID: <35AF9BF8.88668455@seanet.com>

Hi everybody:

Went to UW Library yesterday to look up the Nyle Steiner in the December
6, 1974 issue of Electronic Design (about using diodes as the control
elements in a VCF with lowpass, bandpass and highpass outputs).  Guess
what volume was missing from the library?  AARRGH...

So, does anyone have the filter schematics out there? 

Thanks,

Sean Costello



From urekar.m at EUnet.yu  Fri Jul 17 20:47:37 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Fri, 17 Jul 1998 20:47:37 +0200
Subject: AW: AW: VCS3 Filter Cap values
References: <1BF5E20E0C4DD111BBAB00805FE2D582859BEE@nbgm336a.nbgm.siemens.de>
Message-ID: <35AF9C49.5BCA@eunet.yu>

Haible Juergen wrote:

> BTW, do you have corrected schemos, or did you check
> it on the real thing? Do you know about more errors
> (other than the obviously inverted transistors on Graham's
> site) ?

No , I have the original for VCF and it has this mistake
Never seen inside an vcs3 but I've breadboarded vcf and 
eliminated this cap as I have bad experience with wrong
polarisation on elcos.Found this as only normal explain
so there's 0.01 % chance that I'm wrong :)
For infamous 47kpf I used 47n and it worked ok (well
minimoog vcf sounded better so I ditched the first one).
Never looked other vcs schematics that I have in such 
detail,but I'm going to as it seems.
Now,if only I'd find that matrix board and I'm tangerine
dream  :) 




marjan



From tomg at vivid.net  Fri Jul 17 20:58:01 1998
From: tomg at vivid.net (tomg)
Date: Fri, 17 Jul 1998 13:58:01 -0500
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <199807161407070880.00105282@mail.proaxis.com>
Message-ID: <yam7502.59.120640264@mail.vivid.net>

On 16-Jul-98, Jim Johnson wrote:

>4) Why use an LM3900 in this circuit, rather than a TL-074? 

I used 39OOs to replicate the Serge Boolean Logic Module. This may or may not
be how Serge does it I don't know I've never used a Serge. It works anyway.
Check it out.

Maxx Boolean Logic BLG-1A

The LM39OO "Norton" amplifier uses a inverted current mirror to achieve a
non-inverted input instead of the normal differential input op-amp. This
design allows the amplifiers to be run from a wide range (+4-36V) single
supply solving most of the problems usually encountered running op-amps from a
single supply. The amplifiers of the 39OO can be overdriven and used in low
speed digital applications at more than +5V to supply more current than
standard digital gates. Two inverters ,AND ,OR and XOR gates built around
LM39OOs. May be combined to form NAND, NOR ect...

http://www.tomg.vivid.net/maxx/page_029.html

-Tom





From jamos at technotoys.com  Fri Jul 17 21:23:30 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Fri, 17 Jul 1998 12:23:30 -0700
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <yam7502.59.120640264@mail.vivid.net>
References: <yam7502.59.120640264@mail.vivid.net>
Message-ID: <199807171223300810.0489564F@mail.proaxis.com>

Looks cool and easy to build. What are the logic and threshold levels in
this setup? And would this work equally well with a bipolar supply (I'd
like to set up +- 5v outputs on the logic section of my someday synth.)

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 7/17/98, at 3:03 PM, tomg  wrote: 

>On 16-Jul-98, Jim Johnson wrote:
>
>>4) Why use an LM3900 in this circuit, rather than a TL-074? 
>
>I used 39OOs to replicate the Serge Boolean Logic Module. This may or may
not
>be how Serge does it I don't know I've never used a Serge. It works
anyway.
>Check it out.
>
>Maxx Boolean Logic BLG-1A
>
>The LM39OO "Norton" amplifier uses a inverted current mirror to achieve a
>non-inverted input instead of the normal differential input op-amp. This
>design allows the amplifiers to be run from a wide range (+4-36V) single
>supply solving most of the problems usually encountered running op-amps
from a
>single supply. The amplifiers of the 39OO can be overdriven and used in
low
>speed digital applications at more than +5V to supply more current than
>standard digital gates. Two inverters ,AND ,OR and XOR gates built around
>LM39OOs. May be combined to form NAND, NOR ect...
>
>http://www.tomg.vivid.net/maxx/page_029.html
>
>-Tom



From jfoster at lucasdigital.com  Fri Jul 17 21:39:48 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Fri, 17 Jul 1998 12:39:48 -0700
Subject: ring mod with the AD633
Message-ID: <35AFA884.A4CB4A00@lucasdigital.com>

hi all,
I know this is old hat, but I came across an AD633 today and recalled
the schema on
http://www.hyperreal.org/music/machines/categories/do-it-yourself/schematics/AD633.ringmod.gif

I thought I remembered someone saying this info was out of date or
incorrect for the AD633.
Any thoughts, suggestions or tips about building a ring mod based on the
AD633?

thanks,
Jeff
--
Jeff Foster - 415-662-1254
System/Network Engineer, Skywalkersound, Lucasdigital Ltd.





From magnus at analogue.org  Fri Jul 17 21:47:29 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 17 Jul 1998 21:47:29 +0200
Subject: AW: VCS3 Filter Cap values
In-Reply-To: Your message of "Fri, 17 Jul 1998 12:37:11 +0200"
References: <1BF5E20E0C4DD111BBAB00805FE2D58285457A@nbgm336a.nbgm.siemens.de>
Message-ID: <199807171947.VAA10768@piraya.electrum.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 >> I am in the process of breadboarding the VCS3 filter and was
 HJ> wondering if
 >> anyone knows what value 47Kpf or 10Kpf is as indicated on the
 HJ> schemos that
 >> are out there? 

 HJ> Just multiply the factors. k=1e3, p=1e-12, kp=n=1e-9.
 HJ> As curious as it may look, it's even mathematically 
 HJ> correct. (;->)

Note that while this looks curious it is not at all uncommon with
capacitors. You may find SMD caps marked 103 which means 10*10E3 pF
which is 10 nF. Similar things occur on most cheramics I have seen.

However, writing 47 kpF is not allowed in the SI system, there you are
required to write it as 47 nF. I have seen people using kM and MM
instead of G and T respectively, this is equalently broken.

Thus stacking prefixes is not allowed and is greatly
deprechieated. Things isn't ideal and one must also recall that the SI
system still is fairly young after all. At least there is something to
strive for.

BTW. An US inch is not exactly 25,4 mm as the SI system specifies, the
diff is a few PPM if I recall things right. I guess that most rules
will be the same anyway :)

Another thing, a bilion isn't the same in USA as it is in the rest of
the world. We others stick a miljard in before we get to the bilion.
This shows that these language prefixes can be a source of confusion.

 HJ> BTW: The filter schemos show a 10u capacitor across the
 HJ> CV input ( C31, parallel to the 1k lower divider leg).
 HJ> This will slow down modulation transients. S&H sounds
 HJ> like using a portamento, for example. I have no idea if
 HJ> this is an error in the schemos or if it's actually inside the 
 HJ> VCS3, but I've cut it out on my clone yesterday, and it sounds
 HJ> much better now.

Oups.

Cheers,
Magnus



From Chris.List at sc.siemens.com  Fri Jul 17 23:03:14 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Fri, 17 Jul 1998 17:03:14 -0400
Subject: ring mod with the AD633
Message-ID: <81A062BC5305D111A9D700805F065968CE945D@maildepo.sc.siemens.com>

That's my drawing from long ago.

As far as I know there's nothing wrong with it.

- Chris


> -----Original Message-----
> From:	Jeff Foster [SMTP:jfoster at lucasdigital.com]
> Sent:	Friday, July 17, 1998 3:40 PM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	ring mod with the AD633
> 
> hi all,
> I know this is old hat, but I came across an AD633 today and recalled
> the schema on
> http://www.hyperreal.org/music/machines/categories/do-it-yourself/sche
> matics/AD633.ringmod.gif
> 
> I thought I remembered someone saying this info was out of date or
> incorrect for the AD633.
> Any thoughts, suggestions or tips about building a ring mod based on
> the
> AD633?
> 
> thanks,
> Jeff
> --
> Jeff Foster - 415-662-1254
> System/Network Engineer, Skywalkersound, Lucasdigital Ltd.
> 



From jfoster at lucasdigital.com  Fri Jul 17 23:16:42 1998
From: jfoster at lucasdigital.com (Jeff Foster)
Date: Fri, 17 Jul 1998 14:16:42 -0700
Subject: ring mod with the AD633
References: <81A062BC5305D111A9D700805F065968CE945D@maildepo.sc.siemens.com>
Message-ID: <35AFBF3A.D74539A5@lucasdigital.com>

great, happy I can use it
Jeff

List, Christopher wrote:

> That's my drawing from long ago.
>
> As far as I know there's nothing wrong with it.
>
> - Chris
>
> > -----Original Message-----
> > From: Jeff Foster [SMTP:jfoster at lucasdigital.com]
> > Sent: Friday, July 17, 1998 3:40 PM
> > To:   synth-diy at mailhost.bpa.nl
> > Subject:      ring mod with the AD633
> >
> > hi all,
> > I know this is old hat, but I came across an AD633 today and recalled
> > the schema on
> > http://www.hyperreal.org/music/machines/categories/do-it-yourself/sche
> > matics/AD633.ringmod.gif
> >
> > I thought I remembered someone saying this info was out of date or
> > incorrect for the AD633.
> > Any thoughts, suggestions or tips about building a ring mod based on
> > the
> > AD633?
> >
> > thanks,
> > Jeff
> > --
> > Jeff Foster - 415-662-1254
> > System/Network Engineer, Skywalkersound, Lucasdigital Ltd.
> >



--
Jeff Foster 415-662-1254
Unix Systems/Networks
Skywalkersound, LucasDigital Ltd.





From tomg at vivid.net  Sat Jul 18 01:56:55 1998
From: tomg at vivid.net (tomg)
Date: Fri, 17 Jul 1998 18:56:55 -0500
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <v02130500b1d50b5c9660@[205.139.109.111]>
Message-ID: <yam7502.2791.120501912@mail.vivid.net>

Why didn't you build it? and Whats the scoop on the real BLOG?

-Tom

On 17-Jul-98, R.Fahl wrote:
>Ha ha ha!!!

>That's funny.  I thought about making a BLOG that way.  I know for a fact
>that that is not how Serge did it.  A friend of mine has one and it's all
>CMOS.  It's a newer module.  I think only the first series (pre '79) used
>3900s.


>>The amplifiers of the 39OO can be overdriven and used in low
>>speed digital applications at more than +5V to supply more current than
>>standard digital gates. Two inverters ,AND ,OR and XOR gates built around
>>LM39OOs. May be combined to form NAND, NOR ect...
>>
>>http://www.tomg.vivid.net/maxx/page_029.html
>>
>>-Tom






From pfperry at melbpc.org.au  Sat Jul 18 04:27:27 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 18 Jul 1998 12:27:27 +1000 (EST)
Subject: ring mod with the AD633
Message-ID: <1.5.4.16.19961209190308.2f4f7982@popa.melbpc.org.au>

At 12:39 PM 17/07/98 -0700, Jeff Foster  wrote:
>I know this is old hat, but I came across an AD633 today and recalled
>http://www.hyperreal.org/music/machines/categories/do-it-yourself/schematic
s/AD633.ringmod.gif
......this works OK......
>Any thoughts, suggestions or tips about building a ring mod based on the
>AD633?
....just be careful no hum gets in on the signal side, or it will give
what sounds like an annoying bleedthrough..actually the carrier modulated
by mains hum. The 633 works fine, I've built many ring mods with it, even for
'classical' Stockhausen performance.

paul perrry melbourne australia




From ijfritz at earthlink.net  Sat Jul 18 04:53:03 1998
From: ijfritz at earthlink.net (Ian Fritz)
Date: Fri, 17 Jul 1998 20:53:03 -0600
Subject: motorised pots and other controls
References: <59658d3c.35af7b3d@aol.com>
Message-ID: <35B00E0F.D38F5DCE@earthlink.net>

I have some info on capacitance switches on my web site. They're used in
my wind controller. The design is similar to that in the CMOS Cookbook
and much simpler than the Simonton design. I also have a capacitive
"pressure plate" circuit, which puts out a voltage that increases with
increasing finger pressure. I can't remember where I got the circuit
idea from. It has an rf oscillator followed by a R-C-R tee, with the C
being the sensor plate. This network is followed by a biased rectifier
built around a 3900 Norton amp. Does anyone by chance remember seeing
this before?

There's a good article on capacitive sensors in the Jan. "Electronic
Design". Highly recommended for experimental ideas.

  Ian Fritz  http://home.earthlink.net/~ijfritz


PapaJ59871 at aol.com wrote:
> 
> In a message dated 98-07-16 20:07:06 EDT, sidlar at loon.norlink.net writes:
> 
> << Has anyone here worked on capacitance sensors?  I'm trying to figure out
>  how those star-trek like panels worked :) Inductance, maybe? hmm... >>
> 
> There's some stuff on the capacitive touch switches at
> http://www.paia.com/touchsw.htm .
> 
> -John
>




From shusoran at yahoo.com  Sat Jul 18 08:50:41 1998
From: shusoran at yahoo.com (J. L.)
Date: Fri, 17 Jul 1998 23:50:41 -0700 (PDT)
Subject: How the $@#! does the Moog ladder filter do what it does?
Message-ID: <19980718065041.5268.rocketmail@send1d.yahoomail.com>

Hi, everybody...I've been reading the list for a month or so, but
haven't had a question until now.

I've spent some time looking at the schematic for ther Minimoog ladder
filter from the DIY archive, but I'm having lots of difficulty
understanding it...could someone please enlighten me about its function?

I understand all the nice abstract stuff about what it does, but I'm
just not getting how all the components function together.

Sorry to bother you with this...please don't flame the newbie with a
rather poor understanding of electronics. ;)

-Jonathan




_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com




From tomg at vivid.net  Sat Jul 18 08:56:25 1998
From: tomg at vivid.net (tomg)
Date: Sat, 18 Jul 1998 01:56:25 -0500
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <199807171223300810.0489564F@mail.proaxis.com>
Message-ID: <yam7503.1287.120947816@mail.vivid.net>

On 17-Jul-98, Jim Johnson wrote:
>Looks cool and easy to build. What are the logic and threshold levels in
>this setup? And would this work equally well with a bipolar supply (I'd
>like to set up +- 5v outputs on the logic section of my someday synth.)

The anytime voltage goes above .60V on the non-inverting input of a amplifier
the output goes high. Just depends on the voltage summed.

+- 5% Supply = 12V 

      IN-1 IN-2  OUT

AND   +12  < 9V   L
AND   +12  > 9V   H
OR    GND  < 9V   L
OR    GND  > 9V   H

+- 5% Supply = 5V 

      IN-1 IN-2  OUT

AND   +5   < 4V   L
AND   +5   > 4V   H
OR    GND  < 4V   L
OR    GND  > 4V   H

While I'm at it take a look at the Surge inspired "Dual Trainsient Generator".
I'm sure Surege didn't do this module this way either, and even though it may
be low rent by some peoples standards, this also works...:-)

Maxx Dual Transient Generator DTG-1A
http://www.tomg.vivid.net/maxx/page_030.html


-Tom




From lfo at pacifier.com  Sat Jul 18 09:17:37 1998
From: lfo at pacifier.com (if.then.else)
Date: Sat, 18 Jul 1998 00:17:37 -0700
Subject: making a pcb board.
Message-ID: <35B04C11.FD00C817@pacifier.com>

hello all,

first off thanks for all who answered my 'hi. i'm new" questions.

my question, if there's some schematics of something i what to build
what's the easiesy to design a pcb for it?

thanks,
deno
--
:::::::::...::...::...::...:.:...:...:...:::.:::.::.::.:........:
:::::.::..:::...::::......  if.then.else ::.::.::......::::::::::
::::::.:.:::...::::...::::... www.pacifier.com/~lfo ...::.::.::::
:.:::::..::::...:::::....::.::. ICQ: 8642895 ..:..:..:..:..:::.::
:::..::..::...:.:.:.:...:..:...:. PGP key on request ..........::
::::::::...:::::....::::::..:..:::::::.........::.:..:::::....:::





From urekar.m at EUnet.yu  Sat Jul 18 13:39:54 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 18 Jul 1998 13:39:54 +0200
Subject: Dual transient generator
References: <yam7503.1287.120947816@mail.vivid.net>
Message-ID: <35B0898A.2065@eunet.yu>

> While I'm at it take a look at the Surge inspired "Dual Trainsient Generator".
> I'm sure Surege didn't do this module this way either, and even though it may
> be low rent by some peoples standards, this also works...:-)
> 
> Maxx Dual Transient Generator DTG-1A
> http://www.tomg.vivid.net/maxx/page_030.html


Looking at this DTG and some later moog designs (rogue,micro,prodigy...)
,
I got some ideas to add more options to this circuit,but don't know if
they are any good :

(just for one section of dtg)


cycle switch stays between opamp out and trigger in (6) but treshold (2)
is disconnected and added switch to select (2) connected as before (to
op
amp out) or (2) direct do gnd (sustain off/on)

disconnect "fall" diode from pin (5) and connect it to discharge pin (1)

put switch in parallel to fall diode (modified in previous step) so it
switch normal/diode shorted mode - don't know what it does but it
somehow
affects eg shape in moog

add diode to summing point of 1M pots (anode) then 1k res in series and
then switch with two positions : one with nothing connected so R and D 
don't affect circuit (release on) , and second position connected to 
reset pin (4) (release off ,after attack goes to 0 fast)
(maybe not to (4) but (8) ? )

well,also,in original there's 100R resistor between 10u cap and summing
point of 1M pots and (12) is connected to + input of ompamp rather than
to it's output

is this making any sense ?



marjan



From urekar.m at EUnet.yu  Sat Jul 18 13:42:31 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 18 Jul 1998 13:42:31 +0200
Subject: Serge Waveshaper schemos on Music Machines
References: <yam7503.1287.120947816@mail.vivid.net>
Message-ID: <35B08A27.193E@eunet.yu>

It's not serge ,but here's nice and simple
waveshaper ,while we're at it .

http://www.fortunecity.com/tinpan/humperdinck/223/sawtooth.jpg



marjan



From chordman at flash.net  Sat Jul 18 17:30:01 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sat, 18 Jul 1998 15:30:01 GMT
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <35B08A27.193E@eunet.yu>
References: <yam7503.1287.120947816@mail.vivid.net> <35B08A27.193E@eunet.yu>
Message-ID: <35b0bca8.53494554@mail.lan>

On Sat, 18 Jul 1998 13:42:31 +0200, "<<<marjan>>>" <urekar.m at EUnet.yu>
wrote:

>It's not serge ,but here's nice and simple
>waveshaper ,while we're at it .
>
>http://www.fortunecity.com/tinpan/humperdinck/223/sawtooth.jpg

This looks like a candidate for a VC WaveShaper.  Replace pot P1 with
an OTA.  I really wish this weren't a jpg.  I can't make out the value
of R1.  I tried all kinds of sharpening with PhotoShop, but this one
resistor is ??  It appears to be ?K ohms where ? is a single digit.
5? 2?  No associated parts list...  Shouldn't be too hard to either
figure the correct value out or determine experimentally.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From chordman at flash.net  Sat Jul 18 18:59:04 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sat, 18 Jul 1998 16:59:04 GMT
Subject: Serge Waveshaper schemos on Music Machines CORRECTION !!
In-Reply-To: <v02130500b1d620b4c886@[205.139.109.122]>
References: <v02130500b1d620b4c886@[205.139.109.122]>
Message-ID: <35b4d3d6.59429494@mail.lan>

To do VC Wave Shaping, replace pot P2 with an OTA, not P1 as I wrote
earlier.  

Sheesh, now where'd I put those drugs?


-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From tic at vossnet.de  Sat Jul 18 20:03:21 1998
From: tic at vossnet.de (tim0 (Timo Christ))
Date: Sat, 18 Jul 1998 20:03:21 +0200
Subject: ASM-1 Glide bipolar cap
Message-ID: <35B0E369.2EFA18F0@vossnet.de>

Hi synth-DIYers!

so, i want to use the ASM-1 glide module in my new desktop synth (i will
present it to you when  it?s finished..). I like the design for it?s
simplicity :-) , and i would like to ask what would happen if i:

replace the 1uF bipolar cap with a  2.2 uF bipolar

? 

Thanks !
See you,
Timo
-- 
Timo Christ -- Germany -- Europe	LE TOUR !
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net





From urekar.m at EUnet.yu  Sat Jul 18 21:01:56 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sat, 18 Jul 1998 21:01:56 +0200
Subject: Serge Waveshaper schemos on Music Machines
References: <yam7503.1287.120947816@mail.vivid.net> <35B08A27.193E@eunet.yu> <35b0bca8.53494554@mail.lan>
Message-ID: <35B0F124.370D@eunet.yu>

Scott Gravenhorst wrote:

> This looks like a candidate for a VC WaveShaper.  Replace pot P1 with
> an OTA.  I really wish this weren't a jpg.  I can't make out the value
> of R1.  I tried all kinds of sharpening with PhotoShop, but this one
> resistor is ??  It appears to be ?K ohms where ? is a single digit.
> 5? 2?  No associated parts list...  Shouldn't be too hard to either
> figure the correct value out or determine experimentally.

6k8



marjan



From tomg at vivid.net  Sat Jul 18 22:22:03 1998
From: tomg at vivid.net (tomg)
Date: Sat, 18 Jul 1998 15:22:03 -0500
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <v02130500b1d60937435e@[205.139.109.126]>
Message-ID: <yam7503.189.118577848@mail.vivid.net>

On 18-Jul-98, R.Fahl wrote:
>Man,

>You are on fire!  You're whippin' out a lotta circuits.  Do you actually
>test them before you post them on your site?


Reasonably....I'm sure it's not "Rocket Science" but yeah I actually
build them. Usually twice because the first step is to wishboard it. I have a
206 very cool..:-)... Using real parts with a real power supply and scope.
None of that spice crap. If my designs blow I want to watch 'em go. There is
something secure in touching the parts with your fingers even though sometimes
you get burned...;-)

A lot of people have successfully built stuff from my site, if my mail  is to
be believed and I have no reason to question anyone's integrity.

-Tom





From erik.hecht at mbv.tu-chemnitz.de  Sat Jul 18 23:10:33 1998
From: erik.hecht at mbv.tu-chemnitz.de (Erik Hecht)
Date: Sat, 18 Jul 1998 23:10:33 +0200
Subject: FATMAN from PAIA
Message-ID: <35B10F48.16DEB95F@mbv.tu-chemnitz.de>

Thanks for your advises, but I can get the electronic components much
more cheaper.
And when I buy only the circuit board, I will pay more for shipping than
for the board.
($29.50 + $33.60 :-(  )

Exists in European countries someone who sell this board or the complete
kit?
Have you another idea?

Thanks

Erik.




From cyborg0 at GlobalEyes.net  Sat Jul 18 23:56:58 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Sat, 18 Jul 1998 16:56:58 -0500
Subject: How the $@#! do you FM mod a ladder filter?
References: <19980718065041.5268.rocketmail@send1d.yahoomail.com>
Message-ID: <35B11A2A.38800B1D@globaleyes.net>

Okay, I need to know some of the basics and caveats of FMing a ladder
filter. Where do I inject the signal? It would make sense to inject it
into the cutoff CV, but, could it cause damage? i know i should prlly
put an attenuation pot in there and a coupling cap, but it seems there
would be more to it..any answers?

	also, how does one identify where the poles are? can the response of
these be manipulated as in the Jomox Sunsyn? 
rob




From magnus at analogue.org  Sun Jul 19 00:37:56 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sun, 19 Jul 1998 00:37:56 +0200
Subject: How the $@#! do you FM mod a ladder filter?
In-Reply-To: Your message of "Sat, 18 Jul 1998 16:56:58 -0500"
References: <35B11A2A.38800B1D@globaleyes.net>
Message-ID: <199807182237.AAA19860@piraya.electrum.kth.se>

>>>>> "c" == cyborg0  <cyborg0 at GlobalEyes.net> writes:

Hi!

 c> Okay, I need to know some of the basics and caveats of FMing a ladder
 c> filter. Where do I inject the signal? It would make sense to inject it
 c> into the cutoff CV, but, could it cause damage? i know i should prlly
 c> put an attenuation pot in there and a coupling cap, but it seems there
 c> would be more to it..any answers?

Just apply the signal to cutoff CV, as usual. A DC block cap or not is
up to you, but a pot could be usefull.

Unless you apply normal voltages you should not be able to destroy
anything in the filter, this given that it is not insanely incorrect
in its design and dimensioning. Just give it a little touch of the old
ESD black magic and you will be out safe.

 c> 	also, how does one identify where the poles are? can the response of
 c> these be manipulated as in the Jomox Sunsyn? 

If you are talking about poles as in poles and zeros then you have to
make the rough model of the cursuit transformed into a cap and
resistor thing where the transistors having caps on their emiters
transforms into variable resistors. You must recall that the feedback
of the differential value on the top capacitor when being applied to
the common emitter transistor-pair in the bottom of the ladder will
provide the feedback that moves the poles around.

There are some signs that one should be able to change property quite
a lot but I haven't done the homework properly to tell you how well it
will work.

Cheers,
Magnus




From jamos at technotoys.com  Sun Jul 19 01:10:59 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Sat, 18 Jul 1998 16:10:59 -0700
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <35B0F124.370D@eunet.yu>
References: <yam7503.1287.120947816@mail.vivid.net>
 <35B08A27.193E@eunet.yu>
 <35b0bca8.53494554@mail.lan>
 <35B0F124.370D@eunet.yu>
Message-ID: <199807181610590030.0139925D@mail.proaxis.com>

Don't want to offend anyone, but this actually looks like a pretty poor
excuse for a waveshaper. All it does is derive an in-phase square wave and
mix it in, correct? Not hard to do on any synth with two waveforms and a
mixer.

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 7/18/98, at 3:52 PM, marjan wrote: 

>Scott Gravenhorst wrote:
>
>> This looks like a candidate for a VC WaveShaper.  Replace pot P1 with
>> an OTA.  I really wish this weren't a jpg.  I can't make out the value
>> of R1.  I tried all kinds of sharpening with PhotoShop, but this one
>> resistor is ??  It appears to be ?K ohms where ? is a single digit.
>> 5? 2?  No associated parts list...  Shouldn't be too hard to either
>> figure the correct value out or determine experimentally.
>
>6k8
>
>
>
>marjan



From chordman at flash.net  Sun Jul 19 02:24:55 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sun, 19 Jul 1998 00:24:55 GMT
Subject: Serge Waveshaper schemos on Music Machines
In-Reply-To: <199807181610590030.0139925D@mail.proaxis.com>
References: <yam7503.1287.120947816@mail.vivid.net> <35B08A27.193E@eunet.yu> <35b0bca8.53494554@mail.lan> <35B0F124.370D@eunet.yu> <199807181610590030.0139925D@mail.proaxis.com>
Message-ID: <35b73974.22640660@mail.lan>

On Sat, 18 Jul 1998 16:10:59 -0700, "Jim Johnson"
<jamos at technotoys.com> wrote:

>Don't want to offend anyone, but this actually looks like a pretty poor
>excuse for a waveshaper. All it does is derive an in-phase square wave and
>mix it in, correct? Not hard to do on any synth with two waveforms and a
>mixer.

It looks to me as if the phase of the rectangular wave produced by the
first opamp varies with P2, since the first opamp is a comparator
(according to the text).  This causes the period of the saw wave to
finally double as P2 is moved from 0 to max.  The problem with the
circuit is that it attenuates the signal from full to 1/2 output while
doing this.  That can be compensated for other ways, however.

I'd say that some interesting harmonics, perhaps similar to sync
should be available.  I'm interested enough to throw this one on a
solderless breadboard.  What the heck, it's simple enough.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From tomg at vivid.net  Sun Jul 19 03:12:48 1998
From: tomg at vivid.net (tomg)
Date: Sat, 18 Jul 1998 20:12:48 -0500
Subject: Dual transient generator
In-Reply-To: <35B0898A.2065@eunet.yu>
Message-ID: <yam7503.2420.118581136@mail.vivid.net>

On 18-Jul-98, <<<marjan>>> wrote:

>Looking at this DTG and some later moog designs (rogue,micro prodigy...)
>I got some ideas to add more options to this circuit
>is this making any sense ?

Yes it all makes sense and should all work. It would be a really nice
modification to the basic curcit. But keep in mind everything you do will
affect the cycle function in some way. If you intend to use the cycle function
don't use the 100R resistor. And use the output of the opamp for threshold.
This helps keep the rise/fall rates equal for tri LFO. BTW I have not tried
this but the 555 has a CV input. Maybe the envelope could be modulated.

More Examples

http:/www.tomg.vivid.net/mini4/pics/sd-9.gif   < This adsr came from a old Pop
Ele. Maybe Lancaster? The original didn't work. Took me a while.
Heavy modifications. The ad is the basic DTG.

http:/www.tomg.vivid.net/maxx/pics/adsr1_4.gif < This adrs is a modified
Prodigy ADS 

-Tom




From tomg at vivid.net  Sun Jul 19 03:31:50 1998
From: tomg at vivid.net (tomg)
Date: Sat, 18 Jul 1998 20:31:50 -0500
Subject: How the $@#! does the Moog ladder filter do what it does?
In-Reply-To: <19980718065041.5268.rocketmail@send1d.yahoomail.com>
Message-ID: <yam7503.2537.118581136@mail.vivid.net>

On 18-Jul-98, J. L. wrote:
>Hi, everybody...I've been reading the list for a month or so, but
>haven't had a question until now.

>I've spent some time looking at the schematic for ther Minimoog ladder
>filter from the DIY archive, but I'm having lots of difficulty
>understanding it...could someone please enlighten me about its function?

The voltage drive connected to the base of the emitter transistor causes a
collector current proportional to the exponentiated value of the base voltage
with a scale factor of about 18mv per octive. The collector current is applied
to the transistor ladder. The lower pair of transistor split the the current
into equal parts when no audio is present. When audio is present the standand
current is modulated inversly. As current increases the collector impedance
decreases providing a higher cufoff freq.

Liberated and condensed from the Taurus SM.

-Tom
 




From costello at seanet.com  Sun Jul 19 06:13:38 1998
From: costello at seanet.com (Sean Costello)
Date: Sat, 18 Jul 1998 21:13:38 -0700
Subject: How the heck does the MS-50 filter WORK?
Message-ID: <35B17272.86E84564@seanet.com>

Hi everyone:

Another embarassing post where I reveal how little I know about the
schematics on my own site.  Anyway...

How the heck does the MS-50 filter work?  I'm looking at the schematic
(which you can find at my site - http://www.seanet.com/~costello) and
realizing I don't know what is going on with it at all.  I can figure
out some of it - it's a Sallen-and-Key filter (to be precise, it looks
like a variant of the "equal component value Sallen Key filter" in Don
Lancaster's book, "Active Filter Cookbook").  However, what is the diode
ring doing?  And why the two op-amps providing the control voltage?  I
would really be thankful if some DIY brainiac out there could do an
analysis of the filter, that I could put up on the web site if the
author approves (along the lines of "diodes x y and z act as the first
resistor following the first capacitor, which is this cap").  

Another question:  What do the diodes in the feedback loop do?  I mean,
obviously they provide a clipping type of limiting, but what does that
do for the circuit?  They are in the MS-20 too; what do they do there?

And finally: How do I adapt the circuit for +9 volts? ;)  

Thanks,

Sean Costello

P.S.  My +9 volt obsession is simply out of wanting a compact pedal that
does this stuff.  I'd like to have something that fits in a Budd box to
use with my guitar, or to fit on a tabletop for my TR-606.



From shudder at optusnet.com.au  Sun Jul 19 06:20:46 1998
From: shudder at optusnet.com.au (Sean-E)
Date: Sun, 19 Jul 1998 14:20:46 +1000
Subject: [sdiy] pitch quantizing
Message-ID: <002c01bdb2cc$9bc08580$9a2d8ec6@dialup.mpx.com.au>

This one uses the same system:
http://www.mindspring.com/~clist/resource/circuits/cv_quant.html
and a great page explaining the operation of the Oberheim Mini-Sequencer:
http://aupe.phys.andrews.edu/diy_archive/schematics/sequencers/miniseq/index
.html
Regards,
Sean

-----Original Message-----
From: Ren? Schmitz <uzs159 at uni-bonn.de>
To: Mountain Man <mtman at cloud9.net>; synth-diy
<synth-diy at node12b53.a2000.nl>
Date: Sunday, 3 June 2001 8:11
Subject: Re: [sdiy] pitch quantizing


>At 16:33 02.06.01 -0400, Mountain Man wrote:
>>Actually, voltage quantization for CV's would be fine ... how would I do
>>*that* ?  :)
>
>An discrete solution to that would start with a staircased waveform
voltage.
>(E.g. from a counter and a DAC.)
>Then comparing the input CV with the staircase, as soon as the input is
>greater than the input, you sample&hold the current voltage of the
staircase.
>The counter would have to run pretty fast to get a decent response time.
>
>The polyfusion 2092 quantizer did it that way.
>I have a schematic, if anyone is interested.
>
>
>Cheers,
> Ren?
>
>
>--
>uzs159 at uni-bonn.de
>http://www.uni-bonn.de/~uzs159
>
>
>




From urekar.m at EUnet.yu  Sun Jul 19 11:51:59 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 19 Jul 1998 11:51:59 +0200
Subject: How the heck does the MS-50 filter WORK?
References: <35B17272.86E84564@seanet.com>
Message-ID: <35B1C1BF.3777@eunet.yu>

Sean Costello wrote:

> How the heck does the MS-50 filter work?  I'm looking at the schematic
> (which you can find at my site - http://www.seanet.com/~costello) and

There was nice explanation of this by Juergen Haible and Martin Czech
last year,so here's paste of their mails (if only newer archives exist) 
to save time :


start quote

by JH
You might look at it from another point of view. Don't start with
a cascade at all, but with a simple one-opamp / positive feedback
LPF. The one with a non-inverting amplifier, two resistors in series
from the filter input to the opamp +input, a cap from the opamp
+input to gnd, and a second cap from the resistor connection point
to the output of the opamp. You surely know what I mean. Now replace 
the two (floating) resistors with diodes for voltage control. Use a
symmetrical configuration at the diodes to avoid offset voltages.
Keep the levels down (both from the input and from the feedback 
path), to keep distortion low. Voila !

by MC

The filter control voltage is differential amplified into a positive
and negative voltage (IC 7 a and b, there's a mistake : two times a
?).  These are fed into two diodes of the CA3019 diode array in order
to convert the voltage into an exponential current (pins 4 and 1). This
is the bias current for the diode ring. Note that the control current
is differential in contrast to the normal ladder aproach.  The signal
comes from amp ic6b via coupling capacitor into pin 6. The diodes
between pin 6 and 5 or 6 and 8 serve as current controlled resistors
(see my last mail "diode ladders"). But unlike a normal cascade, the
first stage capacitor is not differential mounted, there are two
capacitors c11 and c12 to ground (almost, there's a 100 Ohm to
ground).  This is necessary because the audio signal is not
differential, again in contrast to the normal ladder. So the signal at
pin 5 and 8 is lowpass filtered in the first stage.  The second stage
is comprised by diodes pin 5 to 2 and pin 8 to 8 and cap c13. The
signal is amplified by 221.8/1.8 (amp IC4f), the amplitude is limited
to four times 0.6V by the diode feedback network D5-D12.  So far this
is a two stage filter, 12dB/oct. The feedback or resonance is
controlled via pot vr10 (bypassed by R50 to get some comfortable
nonlinear characteristic). The feedback is fed via R48 and C15 into the
first stage. This is why C11 and C12 don't go to ground but to R46 with
100Ohm.  C15 seems to provide more feedback for higher frequencys,
maybe to overcome some bandwith limitations of IC4f?

I've done some spice simulation which shows that all this explanation
makes sense.  But : I don't understand the substraction circuit arround
IC6b. It seems always to be the same signal as "Peak", but 6dB larger.
Is this substraction to limit the amplitude for high resonance in order
to get a more "even" signal under all resonance settings? Depending on
the setting of VR10 the circuit sometimes gives a phase reversed
Peak-Signal, sometimes not.


However, a very different circuit. I wonder if it also sounds so
different.  CA3019 is no longer, the other Harris diode arrays seem to
be not suitable, but it should be possible to select 6 matching diodes
out of my box of hundreds of 1N4148.

end quote



marjan



From urekar.m at EUnet.yu  Sun Jul 19 11:52:37 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 19 Jul 1998 11:52:37 +0200
Subject: Dual transient generator
References: <yam7503.2420.118581136@mail.vivid.net>
Message-ID: <35B1C1E5.4314@eunet.yu>

> Yes it all makes sense and should all work. It would be a really nice
> modification to the basic curcit. But keep in mind everything you do will
> affect the cycle function in some way. If you intend to use the cycle function
> don't use the 100R resistor. And use the output of the opamp for threshold.
> This helps keep the rise/fall rates equal for tri LFO. BTW I have not tried
> this but the 555 has a CV input. Maybe the envelope could be modulated.

good idea,it'll modulate output where pots are but it'll affect
both rise and fall

one more thing,if you make mods for release control I mentioned
you can add one 2M log pot in series with that diode ,resistor
and switch to reset pin (4) - you get release control 

and if you diconnect fall diode from (6) as I said and connect it 
to wiper of 10k pot with one end at vcc and other to discharge pin
(1) of 556 you get sustain control

see what I mean of :
http://www.ecr.mu.oz.au/~ndf/synth/gifs/adsr.gif



marjan



From moxie at idonex.se  Sun Jul 19 12:41:29 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Sun, 19 Jul 1998 12:41:29 +0200 (MET DST)
Subject: AW: Steiner-Parker?  Other diode filters?
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5828545C4@nbgm336a.nbgm.siemens.de>
	(message from Haible Juergen on Fri, 17 Jul 1998 12:51:21 +0200)
Message-ID: <199807191041.MAA07832@jolt.idonex.se>

>What other synths used diode filters?  I suspect the Steiner-Parker
>synths used these (perhaps in a state-variable configuration). Did some
>of the older Rolands use diode ladder filters?  Didn't PAiA use diodes
>in some of their filters?

Rolands SH-1000 uses a diode filter. Although mine doesn't work...yet
:-)
/Moxie (Has a half-dead sh1000)




From planet4 at swipnet.se  Sun Jul 19 13:18:40 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Sun, 19 Jul 1998 13:18:40 +0200
Subject: Random LFO...
Message-ID: <35B1D610.15EBF836@swipnet.se>

I though of this idea last night and this is what I came up with:
A white noise generator signal is sent through a sample & hold circuit
which is triggered by a pulse LFO... or even by a gate signal. This
should make a random LFO. Has anyone ever made this before?

Johan





From pfperry at melbpc.org.au  Sun Jul 19 16:05:57 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 20 Jul 1998 00:05:57 +1000 (EST)
Subject: Random LFO...
Message-ID: <1.5.4.16.19961211064137.370f887e@popa.melbpc.org.au>

At 01:18 PM 19/07/98 +0200, Johan Persson  wrote:
>A white noise generator signal is sent through a sample & hold circuit
>which is triggered by a pulse LFO... or even by a gate signal. This
>should make a random LFO. Has anyone ever made this before?

I think the very early Oberheim stand-alone filter had this..
but, what I havn't seen in an effect unit, is an lfo which has the
pulse length randomly variable.....
although I suppose there might be a poisson distribution trigger pulse
generator in the serge or buchla modules somewhere.....

paul perry melbounre austral;ia




From costello at seanet.com  Sun Jul 19 19:22:43 1998
From: costello at seanet.com (Sean Costello)
Date: Sun, 19 Jul 1998 10:22:43 -0700
Subject: How the heck does the MS-50 filter WORK?
References: <35B17272.86E84564@seanet.com> <35B1C1BF.3777@eunet.yu>
Message-ID: <35B22B63.C4FED93A@seanet.com>

<<>> wrote:

> There was nice explanation of this by Juergen Haible and Martin Czech
> last year,so here's paste of their mails (if only newer archives exist)
> to save time :

[excellent info deleted]

Thanks!  It is starting to make sense now.  Question:  What were the
dates of these two emails?  Martin referred to an earlier post of his on
diode ladders, which I would love to see.  If I had a date, I could
download the whole month's mail and search through it.  (If only
Synth-DIY had up-to-date archives!)

Once again, thank you.  I'm constantly amazed at how helpful everyone on
this list is.

Sean Costello




From WeAreAs1 at aol.com  Sun Jul 19 20:39:24 1998
From: WeAreAs1 at aol.com (WeAreAs1 at aol.com)
Date: Sun, 19 Jul 1998 14:39:24 EDT
Subject: MIDI over long cable runs
Message-ID: <6194dda2.35b23d5d@aol.com>


Hello DIY'ers,

I find myself in need of a device that allow me to transmit MIDI data over
very long cable runs (a couple of hundred feet).  Past experience has shown me
that 30 to 40 feet is about the limit for reliable MIDI communication, using
standard MIDI hardware.  There are a couple of companies who make and sell
boxes which will send/recieve MIDI over long cables (J.L. Cooper is one of
them), but I would much rather build my own, if at all possible.  Has anyone
on the list ever made such a box?  

I was thinking that it might be possible to use some of those RS232 interface
driver/reciever chips, such as the MC1488 and MC1489.  The level-shifted
differential signal would be sent down a standard XLR microphone cable.  Does
this sound feasable?  Are those chips fast enough for reliable MIDI data
transfer?  What voltage level would you recommend that I use for the driver
signal?  Are there other interface chips which I should consider using?  

The MIDI signals will be originating from the keyboard of a modern MIDI'd pipe
organ, mainly just to let the organist play the occasional piano or bell/chime
sound from a MIDI module, so the cable and interface won't have to deal with
any high-bandwidth data such as sysex or multi-channel sequencer data.

Thanks for any ideas,

Michael Bacich



From planet4 at swipnet.se  Sun Jul 19 21:56:36 1998
From: planet4 at swipnet.se (Johan Persson)
Date: Sun, 19 Jul 1998 21:56:36 +0200
Subject: MIDI over long cable runs
References: <6194dda2.35b23d5d@aol.com>
Message-ID: <35B24F74.71FEFFD5@swipnet.se>

WeAreAs1 at aol.com wrote:

> Hello DIY'ers,
>
> I find myself in need of a device that allow me to transmit MIDI data over
> very long cable runs (a couple of hundred feet).  Past experience has shown me
> that 30 to 40 feet is about the limit for reliable MIDI communication, using
> standard MIDI hardware.  There are a couple of companies who make and sell
> boxes which will send/recieve MIDI over long cables (J.L. Cooper is one of
> them), but I would much rather build my own, if at all possible.  Has anyone
> on the list ever made such a box?

I would make a box on half the cable length which just takes the signal and send
it through a driver (like a MIDI interface with just in&thru). Just a few
components and no need to think :)

Johan





From urekar.m at EUnet.yu  Sun Jul 19 22:09:46 1998
From: urekar.m at EUnet.yu (<<marjan>>)
Date: Sun, 19 Jul 1998 22:09:46 +0200
Subject: How the heck does the MS-50 filter WORK?
References: <35B17272.86E84564@seanet.com> <35B1C1BF.3777@eunet.yu> <35B22B63.C4FED93A@seanet.com>
Message-ID: <35B2528A.2C11@eunet.yu>

Sean Costello wrote:

> 
> Thanks!  It is starting to make sense now.  Question:  What were the
> dates of these two emails?  Martin referred to an earlier post of his on
> diode ladders, which I would love to see.  If I had a date, I could
> download the whole month's mail and search through it.  (If only
> Synth-DIY had up-to-date archives!)

Is there some archive with 97. ? I know only the one (old ) on
Rick Jensen's  page.

About those posts
 all are 29 Aug 1997

This is Martin's mail you asked :


start quote

Subject: 
        diode ladders
   Date: 
        Fri, 29 Aug 1997 13:28:08 +0200 (MET DST)
   From: 
        Martin Czech <martin.czech at itt-sc.de>
     To: 
        synth-diy at horus.sara.nl



How do ladder circuits work ?

The bias current through a nonlinear device changes the
small signal resistance i.e. a current controlled
resistance.

Ideal diode (and emitter current of transistor as well):

I=Is*[exp(u/Ut)-1] => U=Ut*log(I/Is+1) 

R(I)=dU/dI=Ut/(I+Is) for I>>Is : R(I)=Ut/I

The small signal resistance via the diode or transistor in the
ladder circuit is inverse proportional to the bias current.
Is this correct?

So it is difficult to make a linear response !?

If we chose I=k*exp(a*Uc) (exponential control of bias
current via control voltage Uc), we find:

R(Uc)=Ut/k/exp(a*Uc)=1/k*Ut*exp(-a*Uc)

Now the small signal resistance via the diode or transistor in the
ladder circuit is proportional to some exponential function
of Uc, that's what we need. Add some capacitor and we have first
order lowpass section with exponential control of "R", that is
frequency.
For better offset suppression etc. the whole ladder is made symetrical,
that is : each stage has two resistive devices and one cap between.

O.K.?

But how can a highpass be achieved? Simple exchange of "R" and C won't
work ? Has anybody a schematic of a cascade highpass circuit?

end quote   



marjan



From pfperry at melbpc.org.au  Mon Jul 20 02:36:42 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 20 Jul 1998 10:36:42 +1000 (EST)
Subject: MIDI over long cable runs
Message-ID: <1.5.4.16.19961211171218.0dd7202c@popa.melbpc.org.au>

At 02:39 PM 19/07/98 EDT, Michael Bacich wrote:
>I find myself in need of a device that allow me to transmit MIDI data over
>very long cable runs (a couple of hundred feet).,,,,,,,,,,,,, 
>The MIDI signals will be originating from the keyboard of a modern MIDI'd pipe
>organ, mainly just to let the organist play the occasional piano or bell/chime
>sound from a MIDI module, so the cable and interface won't have to deal with
>any high-bandwidth data such as sysex or multi-channel sequencer data.

it doesn't matter what kind of midi data is being sent, the performance of
the link
is the same (unless you are going to make a whole new protocol).
I would have thought a 50 or 75 ohm coax with video drivers. With these
lengths you 
will have to be sure there is no reflection at the ends. I imagine there are
video 
experts on  this list?

paul perry melbourne australia




From Cary.Roberts at mci.com  Mon Jul 20 05:13:00 1998
From: Cary.Roberts at mci.com (Cary Roberts)
Date: Sun, 19 Jul 1998 22:13 -0500 (CDT)
Subject: MIDI over long cable runs
Message-ID: <19980720051235.QMBQ8978@[166.33.25.2]>

No one has suggested the Anatek MIDI line drivers yet, which will do
exactly what is required.  The units are a pair, and use balanced mic
cable to transmit the MIDI data up to 1000ft I believe.  The units
were fairly inexpensive (under $200) and are, for the time and effort
involved in designing somehting similar, well worth it.

-Cary




From amieuss at telcel.net.ve  Mon Jul 20 05:54:02 1998
From: amieuss at telcel.net.ve (Arturo Mieussens)
Date: Sun, 19 Jul 1998 23:54:02 -0400
Subject: MIDI over long cable runs
Message-ID: <19980720041839.AAA14890@smarty.telcel.net.ve@telcel.telcel.net.ve>

Michael Bacich wrote:

[snip]
> The MIDI signals will be originating from the keyboard of a modern
MIDI'd pipe
> organ, mainly just to let the organist play the occasional piano or
bell/chime
> sound from a MIDI module, so the cable and interface won't have to
deal with
> any high-bandwidth data such as sysex or multi-channel sequencer
data.

This might sound stupid, but...  Why don?t you place the module
closer to the organ and run long balanced audio lines instead of long
midi lines?

I only think you would need long midi cables if the module has to be
played by other controler located far away, and then you could buy a
small synth module for the organ (kurzweil micropiano, alesis
nanopiano and nanosyhtn come to mind), that of course would be more
expensive, but if you have a church or theater that big, money should
be no problem. But then again, why would you be asking to make it
yourself?

Hmmm.. And what if your module doesn?t have balanced output?. Maybe
you don't need it, line level signals can travel far away without
much distortion, or you can get a couple of unbalanced/balanced and a
couple of balanced/unbalanced audio transformers

Anyway, I would use a regular midi in circuit, followed by
amplification (balanced, a couple of op-amps should work), maybe a
differential amplifier (or atenuator, probably) and then a regular
midi out circuit. This seems to be a very simple and usefull project,
maybe i'm wrong about getting another module.

And what if we modify the midi signal comming from the controler and
make it balanced?... this sounds interesting, balanced midi. and of
course we should modify the signal before the module's midi in.
(could a couple of transformers work here?)

Good luck.
Arturo Mieussens.



From Luke at unsw.edu.au  Mon Jul 20 07:47:35 1998
From: Luke at unsw.edu.au (Dearnley, Luke)
Date: Mon, 20 Jul 1998 15:47:35 +1000
Subject: MIDI over long cable runs
Message-ID: <35BA3E1E6E91D111A2CC00A0C98E32F603AAF0@central01-eng.eng.unsw.EDU.AU>


> And what if we modify the midi signal comming from the controler and
> make it balanced?... this sounds interesting, balanced midi. and of
> course we should modify the signal before the module's midi in.
> (could a couple of transformers work here?)
> 
	[Luke]  You would not be able to use a normal DI box (or
similar) here because of MIDI's bandwidth.
	Therefore you would need to make custom boxes for each end. I
suggest it would be easier to build MIDI repeater boxes that other
people have outlined. They would really only need to be a midi in backed
straight onto a midi thru. That starts you measuring length from zero
again.... The trick is to pick opto-couplers with high slew rates. The
only possible problem would be a slight delay if you use too many of
these repeaters in a row. But by far the easiest idea, as Arturo
mentions, is to place the sound module nearer the MIDI controller and
run LONG audio leads. 
	Interesting question though.
	:L uke, out.

	Sub Bass Snarl Sound System
	www.cia.com.au/peril
	 



From maurri at hotmail.com  Mon Jul 20 12:27:50 1998
From: maurri at hotmail.com (Stefano Maurri)
Date: Mon, 20 Jul 1998 03:27:50 PDT
Subject: over 30 modules analogue synth schematics
Message-ID: <19980720102750.26631.qmail@hotmail.com>

I arranged a web page containing technical sheets about my self-built 
modular analogue synthesizer.
Its content could be of great for all people fond of DIY.
I suggest you, if worth, to include this site into your links page; 
address is:

http://diefi.die.unifi.it/~maurri/synth.html

Text are in Italian while schematics are universal !

Cheers
-Stefano Maurri-

e-mail: maurri at diefi.die.unifi.it
e:mail: maurri at hotmail.com
internet: http://diefi.die.unifi.it/~maurri

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From maurri at diefi.die.unifi.it  Mon Jul 20 12:38:42 1998
From: maurri at diefi.die.unifi.it (Stefano Maurri)
Date: Mon, 20 Jul 1998 12:38:42 +0200
Subject: over 30 modules analogue synth schematics
Message-ID: <35B31E32.C5C9C536@diefi.die.unifi.it>

I arranged a web page containing technical sheets about my self-built
modular analogue synthesizer.
Its content could be of great for all people fond of DIY.
I suggest you, if worth, to include this site into your links page;
address is:

http://diefi.die.unifi.it/~maurri/synth.html

Text are in Italian while schematics are universal !

Cheers
-Stefano Maurri-

e-mail: maurri at diefi.die.unifi.it
e:mail: maurri at hotmail.com
internet: http://diefi.die.unifi.it/~maurri




From Juergen.Haible at nbgm.siemens.de  Mon Jul 20 13:15:35 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Mon, 20 Jul 1998 13:15:35 +0200
Subject: AW: How the heck does the MS-50 filter WORK?
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58286CD9D@nbgm336a.nbgm.siemens.de>

A few additions to the basic description:

Diodes in opamp feedback are for soft clipping.
Remember that almost *everything* is better than
an opamp recovering from being stuck at one of
its supply rails.

Note this other, inconspicuous, diode D28. It's used to
sense the ambient temperature, for compensation of
the diode ring's drop voltage.

Also note the resistors in both supply connections of the
ring driver dual opamp, IC7, and the 100 Ohm load resistors
at the opamp outputs. Voltage and current limiting for the
diode ring, without loosing the low output impedance of the
opamps.

I have to correct a little bit of my old mail (which Marjan quoted):
There is another little difference to the standard sallen and key 
filter. Between the two series resistors of the S&K, there is 
a 3rd (shunt) resistor to GND. This is formed by diodes
pin1-9 and pin1-4. It doesn't make much difference, as this
"resistor" is tracking to the other ones. It will affect corner
frequency, attenuation and resonance loop gain, however.
Why these extra diodes ? They prevent the diode ring from
being shortened by the driver opamp outputs. Ok, but one could
have used current sources instead to drive the ring (have seen
this method somewhere else, I think). But the way it is done
in the MS-50, with direct voltage control, the whole diode works
as exponential converter all by itself.

Not bad, these Korg people !!

JH.




From Per.Mattsson at mkv.mh.se  Mon Jul 20 13:21:24 1998
From: Per.Mattsson at mkv.mh.se (Per.Mattsson at mkv.mh.se)
Date: Mon, 20 Jul 1998 12:21:24 +0100
Subject: MIDI over long cable runs
In-Reply-To: <19980720051235.QMBQ8978@[166.33.25.2]>
References: <19980720051235.QMBQ8978@[166.33.25.2]>
Message-ID: <3468881886.14287341@mkv.mh.se>

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From martin.czech at intermetall.de  Mon Jul 20 13:44:20 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 20 Jul 1998 13:44:20 +0200 (MET DST)
Subject: Chaotic Oscillators (over-blown flutes etc)
Message-ID: <199807201144.NAA04554@window.intermetall.de>

>  I'm just wondering if there
> might be a way to simulate the tube and the reed somehow.  The tube is
> like some kind of sympathetic resonator (VCF with rez), the reed some
> kind of relaxation oscillator (saw VCO?), but how to simulate this is
> a mystery to me since obviously most of us have played with a saw VCO
> and a VCF with rez with various parameter settings and it doesn't
> usually sound very much like a clarinet or any other woodwind.  It's
> like the vibrating column of air is a filter that confines the reed's
> vibration to a narrow range of pitches, almost like a PLL.  I'm going
> to keep thinking about this, but I doubt that any circuit I design
> will sound like a clarinet.  (hopefully <g>)

I think  a part of the magic is the feedback between the tube conus and
the reed. The pressure wave from the reed (reed is now open)  moves
forward down the tube and is reflected at the hole at the end. Running
back it influences the reed (shut it off). This way there is a strong
nonlinear feedback between reed and pressure wave in the tube.
Therefore it should be a good idea to model the tube with a delay line
(with a kind of lowpass filter for high frequency damping) and the
reflected wave should sync the oscillator or cause some other kind of
phase jump.  Since the tube is able to carry  a lot of wave modes it is
possible to overblow the instrument.

Thus the tube cannot be modeled with a simple lowpass filter.

m.c.




From martin.czech at intermetall.de  Mon Jul 20 14:08:47 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Mon, 20 Jul 1998 14:08:47 +0200 (MET DST)
Subject: anti-sync
Message-ID: <199807201208.OAA04616@window.intermetall.de>

... all this talking about chaotic systems ...

It appears to me that influencing internal nodes of an oscillator is
essential for interesting nonlinear feedback. In most cases we can
influence the charge current and some circuits provide sync. Syncing
means to force the oscillator phase to some reset level e.g. in order
to achieve phase coherence. Now, one could also think the other way ,
not syncing but pushing the oscillator away,  - anti sync -.  This
could be done by adding some controll voltage to the threshold voltages
of the oscillator ( saw osc. have one threshold, tri have two).
Raising the threshold for some period of time would mean to elongate
the oscillator period (in opposite to shorten it with sync), and of
course also changing the peak value. By clever setup of two oscillators
it seems to be possible that they never come to close in phase, because
they push each other away. Lowering the threshold with a negative
control voltage comes close to weak sync but of course it makes a liite
differerence: changing the threshold may not cause imediate
reset/reverse if the oscillator is still far away whereas sync causes
imediate action. This sounds pretty chaotic to me, it is cheap and easy
to implement and I don't think that a reasonable cicuit will have more
phase jitter or less frequency stability then other cicuits. What do
you think ?




From b.layer at vikingelectronics.com  Mon Jul 20 16:06:27 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Mon, 20 Jul 1998 09:06:27 -0500
Subject: Midi Hammond
Message-ID: <3.0.5.32.19980720090627.007a2320@192.168.210.18>

Hi All,

Is there any info on converting a Hammond tone generator organ to MIDI
control? My main questions are: How could the fact that each key
progressively controls up to nine voices be supported, including at least
some aspect of the key pressure control of these voices (perhaps midi
initial key pressure messages could control the depth to which the virtual
'key' is pressed)? Could the 'drawbars' be supported in software somehow,
to allow multiple user presets? 

Any ideas on this one? 

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From moxie at idonex.se  Mon Jul 20 16:42:19 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Mon, 20 Jul 1998 16:42:19 +0200 (MET DST)
Subject: cook book
In-Reply-To: <3.0.2.16.19980720210254.2adf3e22@mail.internet-zahav.net>
	(message from Gur Milstein on Mon, 20 Jul 1998 21:02:54)
Message-ID: <199807201442.QAA00340@jolt.idonex.se>

> i'm looking for a good cook book for modular systemes,

I suppose you mean for *using* modular systems, since you've already
built one, right?

"Electronic music - Systems, techniques and controls" by Allen
Strange. Absolutely brilliant.

/Moxie (Can't get his SH-1000 to work)




From lkirn at mich.com  Mon Jul 20 18:46:38 1998
From: lkirn at mich.com (Larry Kirn)
Date: Mon, 20 Jul 1998 12:46:38 -0400
Subject: Midi Hammond
References: <3.0.5.32.19980720090627.007a2320@192.168.210.18>
Message-ID: <98Jul20.124421edt.43010@brickwall.ceddec.com>

Hi, Bill

I looked into this a long time ago, and ended up just synthesizing the output,
rather than continue with the tone generator.  The individual harmonics are
not progressive as the note is pressed; they all contact at roughly the same
time.  The reason for this crossbar switch is the fact that the drawbars serve
to route each of the nine individual keyboard busses to a single primary tap
of a current transformer, in order to control volume of that specific
harmonic.  Insertion impedance of as much as an ohm is significant, since
you're dealing with current (not voltage) outputs.  Even with a CPU to figure
out which harmonics went to which note (to avoid duplicate switches per
reluctance coil), there has to be a ton of switches.  When I originally looked
at this, low RDS FETs weren't cheap, but this seems viable if the transformer
were biased enough to keep them on during negative swings.  BTW, one thing to
watch out for that I didn't notice for a while is the fact that additional
uses of a harmonic (more keys pressed with it as a member) don't double its
volume, due to coil resistance.

I easily see your reason for wanting this - there's just nothing like a real
Hammond!

Larry

Bill Layer wrote:

> Is there any info on converting a Hammond tone generator organ to MIDI
> control?




From ebarbour at svetlana.com  Mon Jul 20 20:25:15 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Mon, 20 Jul 1998 11:25:15 -0700
Subject: MIDI for a Hammond
Message-ID: <01BDB3D1.11CE2020.ebarbour@svetlana.com>


>Is there any info on converting a Hammond tone generator organ to MIDI
>control? My main questions are: How could the fact that each key
>progressively controls up to nine voices be supported, including at least
>some aspect of the key pressure control of these voices (perhaps midi
>initial key pressure messages could control the depth to which the virtual
>'key' is pressed)? Could the 'drawbars' be supported in software somehow,
>to allow multiple user presets? 

That's a tough order. There are many MIDI-organ adapters on
the market right now, but to control a Hammond will probably require
driving the keys with solenoids. The drawbars are a BIG job
to control externally--lots of wiring to do. This is why there are
at least 3 Hammond simulators on the market (that I know of), complete with
little drawbar cabinets. They use ROM samples or DSPs to generate
the tones.

You could maybe get a PianoDisc unit and use its solenoids to
drive the keyboard from above or below. The PianoDisc was
designed to drive the far end of each key thru a slot cut in the bottom
of the piano base. (I know this because I helped design the original
PianoDisc back in 1989.) PianoDisc is at www.pianodisc.com.
It is expensive--I believe a system starts at about $5k.

This is a very long file packed with info about Hammonds:
http://theatreorgans.com/hammond/faq/files/faq.txt

Eric Barbour
Svetlana Electron Devices





From aschrock at cs.brandeis.edu  Mon Jul 20 22:12:42 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 20 Jul 1998 16:12:42 -0400 (EDT)
Subject: more ob matrix-1k q's
In-Reply-To: <01BDB3D1.11CE2020.ebarbour@svetlana.com>
Message-ID: <Pine.HPP.3.95.980720151914.19006A-100000@bay.cs.brandeis.edu>

It is with much sorrow that I admit defeat in trying to restore my
matrix-1000. As much as I love it, the bloody thing frankly isn't worth my
while to ship out and try to repair. (I have a working matrix-6r) I'd
rather save my pennies for a kawai k5000r. 

However, I would be interested to hear peoples reactions to the idea of
taking the digital section of the 1000 out of the loop, but keep the
other parts (CEM chips et. all). I would want to either keep the 1000 in
its current case and add a breakout box for knobs, or add patch 
points/knobs to the top of the current case. (I would have to take off the
rack ears, add rubber feet and have a sort of flat desktop unit) Either
solution would keep the 6 3396's, but kill the digital/midi section. 

Of course the problem with this is that the 3396 is controlled digitally..
right?  I assume I'd have to do some AtoD conversion? Any comments? Too
much of a pain? If I can't hack it up it's probably going on the auction
block or the trash. I don't have room for excess junk at this point. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From gur-m at internet-zahav.net  Mon Jul 20 21:02:54 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Mon, 20 Jul 1998 21:02:54
Subject: cook book
Message-ID: <3.0.2.16.19980720210254.2adf3e22@mail.internet-zahav.net>

hi guy's.
i'm looking for a good cook book for modular systemes,
a book with lots of intresting,scintefic block diagrems.
allso any book with the math of FM,AM and relative
math about analog modular synthsis.

thanx
Gur Milstein




From magnus at analogue.org  Mon Jul 20 23:22:37 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Mon, 20 Jul 1998 23:22:37 +0200
Subject: MIDI over long cable runs
In-Reply-To: Your message of "Mon, 20 Jul 1998 10:36:42 +1000 (EST)"
References: <1.5.4.16.19961211171218.0dd7202c@popa.melbpc.org.au>
Message-ID: <199807202122.XAA13022@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 PP> At 02:39 PM 19/07/98 EDT, Michael Bacich wrote:
 >> I find myself in need of a device that allow me to transmit MIDI data over
 >> very long cable runs (a couple of hundred feet).,,,,,,,,,,,,, 
 >> The MIDI signals will be originating from the keyboard of a modern MIDI'd pipe
 >> organ, mainly just to let the organist play the occasional piano or bell/chime
 >> sound from a MIDI module, so the cable and interface won't have to deal with
 >> any high-bandwidth data such as sysex or multi-channel sequencer data.

 PP> it doesn't matter what kind of midi data is being sent, the performance of
 PP> the link
 PP> is the same (unless you are going to make a whole new protocol).
 PP> I would have thought a 50 or 75 ohm coax with video drivers. With these
 PP> lengths you 
 PP> will have to be sure there is no reflection at the ends. I imagine there are
 PP> video 
 PP> experts on  this list?

Not being exactly a video expert in any sence...

For these fairly moderate lengths (considering the blasting speed of
31250 bps) going coax seems a bit of a overkill but it will work
electrically. I doubt that it will be such a nice thing to use on
stage and nearby areas, but that is a matter of personal taste.
An RG-58 or RG-59 can survive some physical abuse, but they are quite
rigid and doesn't really compare to normal signal/mic cable.
To use these cables with a optimum situation one use driver and
receiver that will have a source and load impedance equal to the cable
it is being connected to. Thus, a video cable of 75 ohm is beeing fed
with an amplifier whos output impedance is 75 ohm and terminated in a
receiver with 75 ohm as the input impedance. Note that you should use
75 ohms BNCs with 75 ohms cables, not that it will matter at these
frequencies, but if you want to be compatible with other 75 ohm cables
you should be aware that 75 ohm and 50 ohm BNCs don't mate very
well... they do but one of them destroys the other, not a way to get a
long time reliance.

Anyway, for similar situations is the DMX light control protocol a
good reference. They use about the same speed (if memory servce me
right, I have the papers at work of some reasone) and they use
standard drivers for twisted pair (remember, 10Base-T reaches 185
meters on twisted pair at 10 Mbps). I beleive that they use RS-485.
There are plenty of drivers and receivers of this around that fits
into 8-pin DIP and require little external components (well, contact
and power decoupling cap is a got start). Some standard input
protection might be a thing to consider. DMX use 5-pin XLR, just to
avoid mixups. Picking the right cable with a good mixture of
rugginess, bendiness, damping properties, characteristic impedance
(usually 100-120 ohm) should ensure a success with this method.

Let me just remind you that things like earth-loops and shielding
practices can haunt these longer wirings. You are in luck that the
MIDI output is hooked to an optocoupler, but a consideration on how to
deal with earth loops as well as other problems could pay out in the
long run with less magic dust problems.

Cheers,
Magnus





From tomg at vivid.net  Tue Jul 21 01:10:21 1998
From: tomg at vivid.net (tomg)
Date: Mon, 20 Jul 1998 18:10:21 -0500
Subject: Mini1 morphing to UMaxx 1OO
Message-ID: <yam7505.1077.119300216@mail.vivid.net>

I went out looking for a couple of 3 space rack panels to do a pair of
Mini1cv's on and got a great deal on a 6 space. The more I look at that 6
space the more I see something very different. I think maybe the Mini1cv
chances are slim. Take a look at this and see if I missed anything. Be gentle
with me it's my fist time to ask for comments before I design something.  

1 cv interface glide/pb/attn
2 3374 VCOs
1 single VCO-2A type w/cv
2 LFOs LFO-1A type w/cv
1 S&H noise LFO-2A type with internal 555 clock
2 TGs w/cyle and cv
2 EGs w/cv
2 Ring Mods 
3 CV or Audio mixers
1 Moog type VCF w/FM
1 3372 VCF w/FM
1 Dual VCA w/pan

http://www.tomg.vivid.net/umaxx/pics/pic_001.gif

-Tom




From smart at nn.com  Tue Jul 21 01:47:54 1998
From: smart at nn.com (Mark Smart)
Date: Mon, 20 Jul 1998 18:47:54 -0500 (CDT)
Subject: MIDI for a Hammond
In-Reply-To: <01BDB3D1.11CE2020.ebarbour@svetlana.com> from "Eric Barbour" at Jul 20, 98 11:25:15 am
Message-ID: <199807202347.SAA19344@medusa.nn.com>

>Is there any info on converting a Hammond tone generator organ to MIDI
>control? My main questions are: How could the fact that each key
>progressively controls up to nine voices be supported, including at least
>some aspect of the key pressure control of these voices (perhaps midi
>initial key pressure messages could control the depth to which the virtual
>'key' is pressed)? Could the 'drawbars' be supported in software somehow,
>to allow multiple user presets? 

Pavo makes a kit as part of their MIDITools series, called the 64- or
128-output driver. It takes MIDI note messages and drives high-current sink
outputs in response to them. I dunno how a Hammond keyboard is set up, but
maybe it would be possible to use this kit to replace the switching of the
keyboard, or run in parallel with it. I've been thinking about using this
kit to add MIDI in capability to an ARP Omni.

As for MIDIfying the drawbars...yowza, that sounds really horrendous. Just
MIDIfying the keyboard will be pretty horrendous, come to think of it.
Anyway, you might want to check out the Pavo site (www.pavo.com) to look at
the kits they have available.


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From sebsi23 at hooked.net  Tue Jul 21 05:20:38 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Mon, 20 Jul 1998 20:20:38 -0700
Subject: Random LFO...
References: <35B1D610.15EBF836@swipnet.se>
Message-ID: <35B40905.7031D306@hooked.net>



Johan Persson wrote:

> I though of this idea last night and this is what I came up with:
> A white noise generator signal is sent through a sample & hold circuit
> which is triggered by a pulse LFO... or even by a gate signal. This
> should make a random LFO. Has anyone ever made this before?

uhhhh....ARP 2600 anyone???






From aschrock at cs.brandeis.edu  Tue Jul 21 06:15:25 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 21 Jul 1998 00:15:25 -0400 (EDT)
Subject: Random LFO...
In-Reply-To: <35B40905.7031D306@hooked.net>
Message-ID: <Pine.HPP.3.95.980721001239.19688B-100000@bay.cs.brandeis.edu>

On Mon, 20 Jul 1998, matt wilson wrote:
> Johan Persson wrote:
> > I though of this idea last night and this is what I came up with:
> > A white noise generator signal is sent through a sample & hold circuit
> > which is triggered by a pulse LFO... or even by a gate signal. This
> > should make a random LFO. Has anyone ever made this before?
> uhhhh....ARP 2600 anyone???

Yes.. correct me if I'm wrong, but isn't this the most common use of a
sample+hold circuit? It seems to be what is built into many synths (sh-101
for one, I know there are many others so I won't bother listing). If you
take this random voltage and apply it to say, the VCF cutoff, you get a
nice burbling/rubbery effect. Sounds especially nice on the 101 IMO. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From IGJ at WEIBEL.DK  Tue Jul 21 11:18:15 1998
From: IGJ at WEIBEL.DK (Isac Georg Jensen)
Date: Tue, 21 Jul 1998 10:18:15 +0100
Subject: Diode replacement
Message-ID: <C138D2384146D11186FF00A0C960209202B808@mail.WEIBEL.DK>

Hello list.

I've got this (non-functioning) diode, which is driving me nuts, as I
can't find the specs (and hence a replacement).
It's a D0-35 package (Glass case, orange inside, blue cathode stripe),
not so far from a standard 1N4148.
The only markings on the case, apart from the blue stripe, is the
letters A1 and 12. 
So far I've searched the net for all combinations (A112, 12A1 and so on)
but without luck. Also, I've searched all the databooks at work, but
also without luck.

Any info regarding this component will be highly appreciated. 

Please respond privately, as I'm currently un-subscribed.

-Isac







From moxie at idonex.se  Tue Jul 21 11:53:03 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Tue, 21 Jul 1998 11:53:03 +0200 (MET DST)
Subject: SH-1000 LFO
Message-ID: <199807210953.LAA07135@jolt.idonex.se>

Hi all!

Just a little problem I have:

My SH-1000 isn't feeling very well. Or rather, most parts of it are,
but the saw LFO isn't, and with that neither is the random note
features and some other stuff. Neither is the filter working very
well, but that might have something to do with the strange CVs put out
by the LFO section. Anyway, I've been measuring around a bit and it
seems that the culprit really is the LFO section - up to that point
everything works as it should, and the LFO gets all it's supply
voltages, but it doesn't oscillate.

The LFO on the SH-1000 is built with three normal transistors, one FET
and one weird thingie which looks like a tranny, but has the symbol of
a diode with three legs (?) and a bunch of resistors, caps and a
diode. Anyway, the first and last tranny i believe to be some sort of
buffers, so inbetween them there's one normal transistor, then comes
the three-legged diode thing, then comes the FET (which I suppose works
as a voltage control element of some kind, since the CV from the
"Rate" panel pot is injected somewhere around there). I don't really
know how this is supposed to work - I've been looking around LFO
circuits on the web, but most modern circuits tend to use opamps and
I've never seen any mutant three-legged diodes, so...Anybody out there
knows the circuit and has an explanation on what is supposed to happen
in it?

Also, could anybody direct me to a good transistor/diode replacement
source? This thing uses 2SC373 trannys and 1S1555 diodes, something
none of my parts catalogs or even replacement guides has ever heard of.

Oh, well, I'm all questions. It's a wonderful summers day here in
Sweden, I can tell you, so now I'm off to...work. Oh well.
/Moxie (Looking to lock himself into a stuffy office)





From jezz at enterprise.net  Tue Jul 21 11:53:48 1998
From: jezz at enterprise.net (Jeremy Brookes)
Date: Tue, 21 Jul 1998 10:53:48 +0100
Subject: MIDI over long cable runs
Message-ID: <01BDB4C1.6F467C20@AARDVARK>

>I find myself in need of a device that allow me to transmit MIDI data over
>very long cable runs (a couple of hundred feet).  Past experience has 
shown me
>that 30 to 40 feet is about the limit for reliable MIDI communication, 
using
>standard MIDI hardware.  There are a couple of companies who make and sell
>boxes which will send/recieve MIDI over long cables (J.L. Cooper is one of
>them), but I would much rather build my own, if at all possible.  Has 
anyone
>on the list ever made such a box?
>
>I was thinking that it might be possible to use some of those RS232 
interface
>driver/reciever chips, such as the MC1488 and MC1489.  The level-shifted
>differential signal would be sent down a standard XLR microphone cable. 
 Does
>this sound feasable?  Are those chips fast enough for reliable MIDI data
>transfer?  What voltage level would you recommend that I use for the 
driver
>signal?  Are there other interface chips which I should consider using?

You might want to look at driving the lines with RS485 or RS422 as these 
can drive much further (~1200m) than RS232 (~15m). Just convert the MIDI 
input signal with a standard opto coupler circuit to a TTL signal to drive 
a RS485 chip. Drives into twisted pair cables with a 120ohm termination at 
either end. You can even tap off at any point as it is a multi drop 
interface. Should be dead simple and cost peanuts.

Contact me if you want more details on RS485.

mailto:jezz at enterprise.net
http://homepages.enterprise.net/jezz/





From b.layer at vikingelectronics.com  Tue Jul 21 16:07:25 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Tue, 21 Jul 1998 09:07:25 -0500
Subject: SH-1000 LFO
In-Reply-To: <199807210953.LAA07135@jolt.idonex.se>
Message-ID: <3.0.5.32.19980721090725.007abe70@192.168.210.18>


>The LFO on the SH-1000 is built with three normal transistors, one FET
>and one weird thingie which looks like a tranny, but has the symbol of
>a diode with three legs (?) 

I'm assuming that by 'tranny' you mean transistor. Being a tube guy, I tend
to use that term for transformer. (Come to think of it, car guys would have
asked automatic or manual ovedrive?, I guess...)

My guess is that your mutant 3-leg diode part is an SCR or Thyristor as
they are known, probably used as the relaxation element in the oscillator
(it is a saw osc. right?). The SCR is an off-on device, which cannot be
reset from it's on mode by control voltage; the current loop must be broken
by other means.

Did I make any sense? Hope it  helped.

------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From jezz at enterprise.net  Tue Jul 21 16:46:20 1998
From: jezz at enterprise.net (Jeremy Brookes)
Date: Tue, 21 Jul 1998 15:46:20 +0100
Subject: motorised pots -Reply
Message-ID: <01BDB4C1.71E542E0@AARDVARK>

>Suggestion: How about the little servos that are
>used by Radio Control hobbyists? ~US$30 each...
>they are quite strong and I think all the feedback
>controls are self contained.

Good idea. These need just three wires, +5V, 0V and a control signal which 
is a PWM signal. I used to have the figures on what the PRF and pulse width 
should be. Downside to them is that you would have to disable the drive to 
them once you reached position and even then they would still be quite 
stiff to move due to the gearing in them.

mailto:jezz at enterprise.net
http://homepages.enterprise.net/jezz/




From keen at austin.ibm.com  Tue Jul 21 18:30:15 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Tue, 21 Jul 98 11:30:15 -0500
Subject: motorised pots
In-Reply-To: (Your message of Tue, 21 Jul 98 15:46:20 +0100.)
             <01BDB4C1.71E542E0@AARDVARK>
Message-ID: <199807211630.LAA25838@keen.austin.ibm.com>

A simplified way to do motorized pots is to scavenge the stepper motors
from half-high 5 1/4" diskette drives. Some of these have a shaft
coming out both ends. These are the ones you want. You mount the motor
on your front panel, then couple the pot shaft to the back of the motor
with 1/2" of tygon tubing and an auto hose clamp or glue. These motors
have a 1/4" shaft (matches most pots) and are 180 steps per revolution. 
Find a used computer place and you can often get a pile of these things
for a buck - or offer to haul them away if THEY'LL pay YOU!

There are single chip up-down stepper drivers to turn the pots. The
stepper solution holds its position when un powered, the double shaft
lets you mount it on a panel with standard knobs, and use the knob to
manually adjust, and the stepper chip lets you use digital control,
which presumably you want to do anyways. You can also mount the
motor/pot in an aluminum U channel with the motor inside and the pot
outside the U so that the pot is shielded from motor electrical noise.
Presumably you could also put the stepper driver chip inside the U and
have that noise shielded from delicate audio lines as well. The tubing
also prevents even any electrical contact between the two for further
noise prevention.


It's cheaper, just more assembly required than pre-motorized pots.




From aschrock at cs.brandeis.edu  Tue Jul 21 21:20:36 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 21 Jul 1998 15:20:36 -0400 (EDT)
Subject: matrix-1k FS
In-Reply-To: <01BDB4C1.6F467C20@AARDVARK>
Message-ID: <Pine.SGI.3.95.980721151705.26681E-100000@pearl.cs.brandeis.edu>

Ok, I give up. 

1 broken Matrix-1k FS; display locks up to "111" on startup. Includes 6
3396's. I'll also toss in schematics and the most recent ROM version I got
from Gibson. 

Asking $50+shipping. Best offer over this wins. Prepayment only. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|




From Dr_Forrester at webtv.net  Tue Jul 21 23:09:13 1998
From: Dr_Forrester at webtv.net (R. Hess)
Date: Tue, 21 Jul 1998 17:09:13 -0400 (EDT)
Subject: matrix-1k FS
Message-ID: <17710-35B50379-6583@mailtod-121.bryant.webtv.net>


>1 broken Matrix-1k FS; display locks up to
>"111" on startup. Includes 6 3396's. I'll
>also toss in schematics and the most
>recent ROM version I got from Gibson.
>Asking $50+shipping. Best offer over this
>wins. Prepayment only.
I can do $65. Please let me know if you accept another offer.
 Thanks,
 Richard Hess
 dr_forrester at webtv.net




From aschrock at cs.brandeis.edu  Wed Jul 22 02:31:13 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 21 Jul 1998 20:31:13 -0400 (EDT)
Subject: matrix-1k FS
In-Reply-To: <Pine.SGI.3.95.980721151705.26681E-100000@pearl.cs.brandeis.edu>
Message-ID: <Pine.HPP.3.95.980721202950.20801D-100000@bay.cs.brandeis.edu>

Wow, maybe I should go into buisness selling matrix-1000's, considering 
the number of replies I got! 

In any case, the unit has been spoken for. I would reply to people
individually, but there are a dozen replies, and well, I'm tired :)

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|




From sasami at blaze.net.au  Wed Jul 22 05:15:02 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 22 Jul 1998 05:15:02 +0200 (MET DST)
Subject: motorised pots
Message-ID: <199807220315.FAA13344@mailhost.bpa.nl>

>A simplified way to do motorized pots is to scavenge the stepper motors
>from half-high 5 1/4" diskette drives. Some of these have a shaft
>coming out both ends.

The Steppers more likely to have shafts from both ends are those used in
hard drives. If you want circuitry to drive the steppers, the control boards
from the FLOPPY drives are probably ideal. They have direction and step
inputs, meaning they are simple to drive, and like the steppers themselves,
these boards are throw-away material.

Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From tomg at vivid.net  Wed Jul 22 07:17:18 1998
From: tomg at vivid.net (tomg)
Date: Wed, 22 Jul 1998 00:17:18 -0500
Subject: New DIY VCO Maxx VCO-4A
Message-ID: <yam7507.904.120663832@mail.vivid.net>

I keep looking for the perfect DIY VCO. I may have found it.

Maxx VCO-4A

The VCO-4A is modified from the Moog Prodigy. It features saw ,pulse ,tri 
and sine waves. fm, sync, and pulse width mod. It can be build with two
TLO74s, one 3O46 and one 2N4392. The tri out is very good with only a tiny
hook at the top of the wave. The sine being derived from the tri exhibits the
same small glitch but WOW! is it nice. Sync is not yet implemented I was so
excited I had to post it right away. Future development includes Sync and a
dual version. I'll do a parts list and pc-layout in the next few days.

http://www.tomg.vivid.net/maxx/page_031.html

-Tom 




From tomg at vivid.net  Wed Jul 22 08:10:02 1998
From: tomg at vivid.net (tomg)
Date: Wed, 22 Jul 1998 01:10:02 -0500
Subject: DIY VCO Maxx VCO-4A
Message-ID: <yam7507.125.120851016@mail.vivid.net>

Oh...Tri to Sine converter by Rick Jansen. Thanks Rick! Works Great.
I fixed the tri hook by changing all those 1OKs on the NPN collector
to 1%. hehehehe You guys don't know how long I worked on this. It's
soooo cool.

http://zoutmijn.bpa.nl/Rick.Jansen/Emusic/VCO/VCO.html




From don at till.com  Wed Jul 22 09:02:00 1998
From: don at till.com (Don Tillman)
Date: Wed, 22 Jul 1998 00:02:00 -0700 (PDT)
Subject: Nixie Tubes in Newsweek (!!!)
Message-ID: <199807220702.AAA03844@shell9.ba.best.com>

We just had a Nixie Tube discussion a little while ago, and now you
can see them mentioned in the latest issue of Newsweek, a little
article about the MOSCOW, Museum Of Soviet Calculators On the Web.

http://www.comcen.com.au/~adavie/slide/calculator/soviet.html

(A Dave Barry says, "I swear I'm not making this up".)

  -- Don



From blacet at metro.net  Wed Jul 22 10:46:00 1998
From: blacet at metro.net (John Blacet)
Date: Wed, 22 Jul 1998 08:46:00 +0000
Subject: 76477 TI sound chips
Message-ID: <35B5A6C9.6472@metro.net>

Hi DIYrs:
We have just uncovered another batch of 76477s and have a few dozen
extra that we can release. These are $12 each, minimum order two. Add
7.5% sales tax in CA. Shipping anywhere is $3. If you need a copy of the
16 page data sheet, please add $2. Checks or MO should be made out to
"Blacet Research".

Regards.
-------------------------
John Blacet
Blacet Research Music Electronics
15210 Orchard Rd
Guerneville CA 95446
-------------------------
blacet at metro.net
http://metro.net/blacet/music.html



From Juergen.Haible at nbgm.siemens.de  Wed Jul 22 12:00:40 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 22 Jul 1998 12:00:40 +0200
Subject: test - please ignore
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58287BA0F@nbgm336a.nbgm.siemens.de>

sorry



From Juergen.Haible at nbgm.siemens.de  Wed Jul 22 12:30:54 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 22 Jul 1998 12:30:54 +0200
Subject: AW: Midi Hammond
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58287E798@nbgm336a.nbgm.siemens.de>


	>The individual harmonics are
	>not progressive as the note is pressed; they all contact at roughly
the same
	>time.  

Hmm, I don't own a Hammond, but I used to own a Farfisa, which also
had a lot of separate contacts under each key. And at least here,
with this VIP 345, it made a great difference how fast you played
the keys. Depressing a key slowly, one could clearly hear the harmonics
come in one by one. While this is not exactly your standard playing
style, it still demonstrates that you *can* phrase individual notes
differently. Velocity sensitive keyboard, though the velocity is hard
wired to a single and very special parameter ...
One might be able to emulate this with midi to a certain degree. But
besides the enormous amount of electronics required, keep in mind
that usual Velocity sensing only determines the time window between
two positions of a key, and *how* the key is moved between these
points. A linear approximation should give a good approximation,
I guess.

JH




From Juergen.Haible at nbgm.siemens.de  Wed Jul 22 12:48:36 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Wed, 22 Jul 1998 12:48:36 +0200
Subject: original and ingenious circuits ... (was: in How the heck does th
	e MS-50 filter WORK?)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D58287E7E1@nbgm336a.nbgm.siemens.de>

	>>Not bad, these Korg people !!
	>.....certainly, the Korg ckts are highly original and creative!
	[...]
	>One of the most interesting things about synths is the way some are
designed
	>originally, while others are cobbled together from bits from all
over..
	>paul perry melbourne australia

Wouldn't this make a great thread for the diy list? Original circuits
in commercial synths, instead of variations on well proven previous
circuits ?

I mean, I don't have anything against the latter, but the greatest joy in
reading these old schemos is when I find something that is really
different from previous stuff.

Many of these things are well known meanwhile, and I don't want
to start another "praise your favorite low pass filter" ... (;->)

So, what little circuit details made the greatest impression on all
of you ? What I have in mind is *not* "what new function / module"
(would be another interesting thread, though), but what are the most
astounding realizations of certain functions ? (to give one example,
one of these things was when I discovered the ARP phaser cascade ...)

So, if you like this topic, write what were important circuit discoveries
for you !

JH.



From martin.czech at intermetall.de  Wed Jul 22 13:27:00 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 22 Jul 1998 13:27:00 +0200 (MET DST)
Subject: original and ingenious circuits ... (was: in How the heck does th
	e MS-50 filter WORK?)
Message-ID: <199807221127.NAA20907@window.intermetall.de>

> So, if you like this topic, write what were important circuit discoveries
> for you !
> 
I don't know if Serge Tchernepin actually used Norton-OpAmps in his
designs, but he has severall patents about these current mirror input
stage designs.  It was quite interesting to see how voltage controlled
impedance and thus voltage controlled phasers/filters etc. can be
realized. Also wave-shapers, rectifiers and current integrators (which
can also be found on the LM3900 data sheet).

m.c.




From pfperry at melbpc.org.au  Wed Jul 22 15:06:04 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 22 Jul 1998 23:06:04 +1000 (EST)
Subject: original and ingenious circuits ... 
Message-ID: <1.5.4.16.19961214054135.34ef47f4@popa.melbpc.org.au>

At 12:48 PM 22/07/98 +0200, Juergen.Haible wrote:

>So, what little circuit details made the greatest impression on all
>of you ? 

The VCA of the MS20 impresses me, because I STILL cant see how it works.

paul perry melbourne australia




From Chris.List at sc.siemens.com  Wed Jul 22 15:53:14 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 22 Jul 1998 09:53:14 -0400
Subject: original and ingenious circuits ... (was: in How the heck doe
	s the MS-50 filter WORK?)
Message-ID: <81A062BC5305D111A9D700805F065968CE9469@maildepo.sc.siemens.com>

Actually, one of my favorites was one you told me about! The ARP (I
beleive that's who it was) cv quantizer. I had always been thinking that
the way to quantize was to run the input through a ADC then to a DAC
with the low bits disconnected - this gets very expensive very quickly
if you want multiple channels. The ARP method, OTOH, uses a fixed
frequency stepped voltage oscillator (that could be made from - among
other things - a counter and a DAC) to drive a comparator + S&H. As soon
as the input voltage crosses the stepped voltage, you sample and hold
the stepped voltage at the output. You can have as many channels as you
want, just by adding more comparator + S&H elements connected to the
same stepped voltage! That's cool!

- CList

> -----Original Message-----
> From:	Haible Juergen [SMTP:Juergen.Haible at nbgm.siemens.de]
> Sent:	Wednesday, July 22, 1998 6:49 AM
> To:	Paul Perry; DIY
> Subject:	original and ingenious circuits ... (was: in How the
> heck does the MS-50 filter WORK?)
> 
> So, what little circuit details made the greatest impression on all
> of you ? What I have in mind is *not* "what new function / module"
> (would be another interesting thread, though), but what are the most
> astounding realizations of certain functions ? (to give one example,
> one of these things was when I discovered the ARP phaser cascade ...)
> 
> So, if you like this topic, write what were important circuit
> discoveries
> for you !
> 
> JH.



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From: kcolleran at neato.com (Kevin Colleran)
Date: Wed, 22 Jul 1998 10:01:25 -0400
Subject: Special Deal for the list
Message-ID: <35B5F0B5.87772923@neato.com>

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From Chris.List at sc.siemens.com  Wed Jul 22 17:07:31 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Wed, 22 Jul 1998 11:07:31 -0400
Subject: original and ingenious circuits ...
Message-ID: <81A062BC5305D111A9D700805F065968CE946D@maildepo.sc.siemens.com>

There you go, maybe that's where the original idea came from - I don't
know why ARP stuck in my head, maybe they had the same thing? 

> -----Original Message-----
> From:	Bright Boy [SMTP:jdec at mindspring.com]
> Sent:	Wednesday, July 22, 1998 1:37 PM
> To:	List, Christopher; synth-diy at mailhost.bpa.nl
> Subject:	Re: original and ingenious circuits ...
> 
> List, Christopher wrote:
> > 
> > Actually, one of my favorites was one you told me about! The ARP (I
> > beleive that's who it was) cv quantizer. 
> 
> The quantizer in the Oberheim 2-Voice Sequencer is implemented in the
> *exact* same way and works quite well!!!!
> 
> Head over to www.synthfool.com to take a look at the schematic....
> 
> Cheers,
> 
> Jeff R. Dec



From b.layer at vikingelectronics.com  Wed Jul 22 18:55:14 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 22 Jul 1998 11:55:14 -0500
Subject: AW: Midi Hammond
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58287E798@nbgm336a.nbgm.sieme
 ns.de>
Message-ID: <3.0.5.32.19980722115514.007a52f0@192.168.210.18>

At 12:30 PM 7/22/98 +0200, you wrote:
>
>	>The individual harmonics are
>	>not progressive as the note is pressed; they all contact at roughly
>the same
>	>time.  
>
What?

>Hmm, I don't own a Hammond, but I used to own a Farfisa, which also
>had a lot of separate contacts under each key. And at least here,
>with this VIP 345, it made a great difference how fast you played
>the keys. Depressing a key slowly, one could clearly hear the harmonics
>come in one by one. While this is not exactly your standard playing
>style, it still demonstrates that you *can* phrase individual notes
>differently. 

I must agree. I'm no Hammond expert, but I was under the impression (from
my Hammond-palying friends) that the ability to control note phrasing with
key pressure is a major feature of the Hammond tone wheel series. On my
humble M-3, I can very deliberately control the fullness of voice by
playing gently or firmly. This is especially apparent when using the
percussion voice. 

My simple concept for controlling fullness with the MIDI 'initial key
pressure' message involves direct corrolation/quantization of the pressure
value to the number of harmonics to be included in the note. A hard
keypress would fold in all harmonics, while a moderate keypress would fold
in fewer harmonics, and a light touch might deliver only the fundamental etc..

Seems like it could work.


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From ebarbour at svetlana.com  Wed Jul 22 19:03:53 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Wed, 22 Jul 1998 10:03:53 -0700
Subject: tube VCF article
Message-ID: <01BDB558.08BB8B20.ebarbour@svetlana.com>

All:
My tube VCF circuit article has finally been posted:

http://home.earthlink.net/~mccorquodale/eng_music/article9.html

If anyone decides to try building it, please let us all know.


Eric Barbour
Svetlana Electron Devices





From ebarbour at svetlana.com  Wed Jul 22 19:11:27 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Wed, 22 Jul 1998 10:11:27 -0700
Subject: more on tube VCF article
Message-ID: <01BDB559.178BDA00.ebarbour@svetlana.com>

>>http://home.earthlink.net/~mccorquodale/eng_music/article9.html
>>If anyone decides to try building it, please let us all know.

Oh, and I forgot:
Please forgive the formatting and peculiar characters in the text (I forgot
to convert it from Mac format). Also forgive my bit of sarcasm about Moog
ladders. It was a late night rush, and i was tired.........

If you need a power supply design for this, let me know.
One will eventually be posted to the Electronic Musician;
it may be a few months.

Eric Barbour
Svetlana Electron Devices





From jdec at mindspring.com  Wed Jul 22 19:36:36 1998
From: jdec at mindspring.com (Bright Boy)
Date: Wed, 22 Jul 1998 10:36:36 -0700
Subject: original and ingenious circuits ...
References: <81A062BC5305D111A9D700805F065968CE9469@maildepo.sc.siemens.com>
Message-ID: <35B62324.5D8F@mindspring.com>

List, Christopher wrote:
> 
> Actually, one of my favorites was one you told me about! The ARP (I
> beleive that's who it was) cv quantizer. I had always been thinking that
> the way to quantize was to run the input through a ADC then to a DAC
> with the low bits disconnected - this gets very expensive very quickly
> if you want multiple channels. The ARP method, OTOH, uses a fixed
> frequency stepped voltage oscillator (that could be made from - among
> other things - a counter and a DAC) to drive a comparator + S&H. As soon
> as the input voltage crosses the stepped voltage, you sample and hold
> the stepped voltage at the output. You can have as many channels as you
> want, just by adding more comparator + S&H elements connected to the
> same stepped voltage! That's cool!

The quantizer in the Oberheim 2-Voice Sequencer is implemented in the
*exact* same way and works quite well!!!!

Head over to www.synthfool.com to take a look at the schematic....

Cheers,

Jeff R. Dec



From tomg at vivid.net  Wed Jul 22 20:05:52 1998
From: tomg at vivid.net (tomg)
Date: Wed, 22 Jul 1998 13:05:52 -0500
Subject: original and ingenious circuits ...
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58287E7E1@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7507.2609.119542792@mail.vivid.net>


The SAD1024 clock in the original Electric Mistress flanger uses a 4013 for a
LFO. I'm still puzzled by that one.

-Tom
 




From LEG at btinternet.com  Wed Jul 22 22:53:35 1998
From: LEG at btinternet.com (george & lorraine)
Date: Wed, 22 Jul 1998 21:53:35 +0100
Subject: CEM CHIPS
Message-ID: <01bdb5b2$cba47200$LocalHost@windows95>

Hi all
I have a CEM chip cat: and price list from about four month's ago.SOMEBODY please tell me the site address !!.I will drink powdered glass later this evening.

live long and prosper

george
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From dbalvage at ptdcs2.ra.intel.com  Wed Jul 22 23:57:11 1998
From: dbalvage at ptdcs2.ra.intel.com (Duane R Balvage)
Date: Wed, 22 Jul 1998 14:57:11 -0700
Subject: ADV-Cymbal
Message-ID: <35B66037.237C@ptdcs2.intel.com>

Hey all -

The guys over at MAP are in the middle of getting the ADV-Cymbal

together, and it looks like it has the potential to be an AWESOME

little noisemaker... trouble is, it's a big investment on their side,

and they want to make sure it sells, so they have a feedback section

to tell your opinion on whether you'd be interested or not. 

I don't work for MAP or Tom Henry or any of the other great folks

over there - I just would like to see this module come out.

I have responded, and here is an excerpt:

"Thanks for the feedback.  The good news is that the printed circuit
board quote 
came in lower than expected (making an even better price). The bad news
is that not very many people have responded, so we still can't tell if
this project will see the light of day.  Be sure to tell all your
friends! Thanks."

Best wishes,

Tom

Sooo... Go check it out, give 'em your opinion, good, bad, or 

indifferent. %^P

  http://prairie.lakes.com/~map/whatsnew.html

Personally, I think it will be a pretty cool cymbal module - check out 

that schemo!!

				- 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 sasami at blaze.net.au  Thu Jul 23 00:11:44 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Thu, 23 Jul 1998 00:11:44 +0200 (MET DST)
Subject: tube VCF article
Message-ID: <199807222211.AAA27872@mailhost.bpa.nl>


>Eric Barbour wrote:
>My tube VCF circuit article has finally been posted:
>
>http://home.earthlink.net/~mccorquodale/eng_music/article9.html
>
>If anyone decides to try building it, please let us all know.

Mine's well on the way. PSU is finished, and the signal section of the
filter is nearly complete. I should be able to power this part up some time
this weekend. I'll put photos up when I've finished it.

The PSU was a challenge, built using only parts to hand. The 6.3V is
provided by an 8V torriod transformer, rectified, smoothed and dropped to
the correct voltage through a string of eight 11-amp power diodes. The HT
transformer is a 240 to 115V stepdown transformer designed for running US
appliances in Australia.

Ken
_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
         ** Australian Miniature Horses and ponies **
             <http://www.blaze.net.au/~sasami/>
_____________________________________________________________





From magnus at analogue.org  Thu Jul 23 01:12:52 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Thu, 23 Jul 1998 01:12:52 +0200
Subject: original and ingenious circuits ... (was: in How the heck does the MS-50 filter WORK?)
In-Reply-To: Your message of "Wed, 22 Jul 1998 09:53:14 -0400"
References: <81A062BC5305D111A9D700805F065968CE9469@maildepo.sc.siemens.com>
Message-ID: <199807222312.BAA18503@piraya.electrum.kth.se>

>>>>> "LC" == List, Christopher <Chris.List at sc.siemens.com> writes:

Hi People!

Thanks Juergen for forking of a interesting thread. You are right,
there is something special about these odd solutions. I just love to
find these myself, and even how bizzare they may get they may still be
fully adequate for it's application at the time it was created.

 LC> Actually, one of my favorites was one you told me about! The ARP (I
 LC> beleive that's who it was) cv quantizer. I had always been thinking that
 LC> the way to quantize was to run the input through a ADC then to a DAC
 LC> with the low bits disconnected - this gets very expensive very quickly
 LC> if you want multiple channels. The ARP method, OTOH, uses a fixed
 LC> frequency stepped voltage oscillator (that could be made from - among
 LC> other things - a counter and a DAC) to drive a comparator + S&H. As soon
 LC> as the input voltage crosses the stepped voltage, you sample and hold
 LC> the stepped voltage at the output. You can have as many channels as you
 LC> want, just by adding more comparator + S&H elements connected to the
 LC> same stepped voltage! That's cool!

This is a interesting twist on things. I like it. For a one channel
application you could do with a quick counter (or better, an SAR) and
stop at the level and keep this until next sample period. If one use a
slow enougth lowpass filter at the output will the approximation
period hardly be noticed and you get a simpler S/H cursuit.

This made me think of a box that I think is about the most bizzare box
that I have seen, and I don't that all people really know all the
twist on this one... it is not all analog, but anyway, it's the
Eventide Harmonizer H949 from 1979. It will do a little set of
programs and has some digital and some analog program parameter
changes. There is many things to be noted about this box, but here is
a few.

In order to pitch the sound it needs to be sampled and played up, for
this will the sound first pass a 7-pole Butterworth lowpass filter and
then be compressed through a dBx compressor card. It is then being
sampled at a rate of about 50 kHz. In order to A/D convert they
kick-start a rampwave that is being compared with the sampled
value. At the same time that they started the ramp a counter started
counting frenetically. When the ramp reaches the sampled voltage is
the counters value stored into memory (which is very early DRAM). Now,
a fast excercis with numbers will tell you that to get a few usefull
bits there can be a terrible number of counts, and this is also how it
works. To get the 11 bits will the counter need to count 2048. Since
2048 counts every 50 kHz cylce or so we need the counter to tick in
about 102,4 MHz. This frequency is generated by a LC-oscillator and a
couple of transistors. The frequency is trimmed by adjusting the core
of the coil. There is both ECL and STTL running at this frequency,
since it will also control most of the other digital clock as well.
You can feel the LSB of the counter since this will run at 50 MHz and
head up the LSB DRAM from it's only input pin!
The highspeed clock is also derived down to a base clock for a 16 bit
2901 bit-slice ALU. This ALU section is together with many other
functions controled by TTL PROMs with a width of 48 bits (VLIW!) which
runs in a looped sequence. Some of the program buttons will modify the
bitstream from the PROMs prior to reaching active logic.
The ALU will not touch data itself, it will only be able to read at
various points in memory. Actually, the ALU will only perform address
calculations. The data read by the ALU is feed to CMOS FIFO banks
prior to reaching the D/As. The output of the D/As is feed to 7-pole
Butterworth filters and dBx expander cards. There is two outputs, main
and delay. The output signals can then be mixed and EQed before beeing
sent back into the input path, this allowing some wierd stuff.
On the control side one should notice not only the manual dial, but
also that the backside contains both frequency tracking and CV inputs
(yes, you can hook it up to a modular!). Both the main and the delay
outputs can be assigned a fixed delay with buttons (you punch in the
delay digitally on 6 buttons per output). On the positive side is that
both input and outputs are fully balanced on XLRs.
I even have a extra algorithm card which I still doesn't really know
how it works.
The analog control side of this box contains 2 SSB generators, which
then are used to control the ALU (obviously).

There is an interesting button on the input labeled REPEAT, which
actually causes the memory to stop updateing, you have just sampled
what was in the memory and are able to play it on you CV kerboard!

The box was marketed with a said dynamic of 96 dB.

This box uses as said a fine suite of ECL, TTL, STTL, LSTTL,
4000-CMOS, 74Cxx-CMOS, analog, radio to combine into a really odd
machine.

To me this is among the more oddly once that I ever encountered in the
audio fx department. It will fills it's 2HE rackrange very nicely.
It is a bit cumbersome to get up stable, but I think it is time to do
something to mine... there is even a track record on mine so I think I
know a set of albums where it apears, of course there is some
interesting effects done!

I still lack a users manual for it, but I should have the schematics
somewhere around (I looked but did not find).

The LFO in the EH SmallStone is a nice one as well, it is based around
one CA3094. Hell, I like the rest of the SmallStone as well, I just
lack a few features...

Cheers,
Magnus



From sebsi23 at hooked.net  Thu Jul 23 02:04:23 1998
From: sebsi23 at hooked.net (matt wilson)
Date: Wed, 22 Jul 1998 17:04:23 -0700
Subject: forthcoming review of paia midi2cv8
Message-ID: <199807230003.RAA22104@mom.hooked.net>

i have just finished building and testing the paia midi2cv8
and will be posting a review in a week or so. i don't have
archive access right and do not know whether this has
been done yet by anyone on the list.

also i'd like some input from others who have built and
used the kit. 

as a tasty tidbit preview, i will say that its a great kit with
some very limited features that are directly related to the
extremely cheap cost. this is not a bad thing! stayed tuned.  


Matt Wilson, Odyssey Studios
               on the web: www.wenet.net/~sebsi23
                          on the phone: 415 675-4886
                                    on the email: sebsi23 at hooked.net				
                            




From afas at git.com.au  Thu Jul 23 05:06:26 1998
From: afas at git.com.au (geoffery francis james)
Date: Thu, 23 Jul 1998 11:06:26 +0800
Subject: synth diy archive
Message-ID: <199807231516.XAA12549@defiant.git.com.au>

does anyone know what has happened to the index synth diy?

. my request was answered with "no files available"
regards
geoff james



From lheckman at juno.com  Thu Jul 23 06:23:23 1998
From: lheckman at juno.com (Lucas A Heckman)
Date: Wed, 22 Jul 1998 23:23:23 -0500
Subject: Atari POKEY Sound Chip
Message-ID: <19980722.232324.8750.1.lheckman@juno.com>

Has anyone ever attempted to utilize the Atari POKEY sound chip in some
sort of noise making unit?  I would like to hear any ones ideas on this
because I think it is capable of  making some great sounds.  By the way,
for some technical info. on it check out
www.xmission.com/~trevin/atari/atari.html.
Lucas

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]



From pfperry at melbpc.org.au  Thu Jul 23 08:38:13 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 23 Jul 1998 16:38:13 +1000 (EST)
Subject: SH-1000 LFO
Message-ID: <1.5.4.16.19961214231342.38ef689c@popa.melbpc.org.au>


>>The LFO on the SH-1000 is built with three normal transistors, one FET
>>and one weird thingie which looks like a tranny, but has the symbol of
>>a diode with three legs (?) 
>
my guess is a unijunction transistor (UJT) widely used at this period
for oscillators (eg in the notorious 'Stylophone')

paul perry melbourne australia




From Juergen.Haible at nbgm.siemens.de  Thu Jul 23 12:18:55 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 23 Jul 1998 12:18:55 +0200
Subject: AW: original and ingenious circuits ... (was: in How the heck doe
	s the MS-50 filter WORK?)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5828977DC@nbgm336a.nbgm.siemens.de>


	[great description of Eventide omitted]

	>The LFO in the EH SmallStone is a nice one as well, it is based
around
	>one CA3094. Hell, I like the rest of the SmallStone as well, I just
	>lack a few features...

Very nice circuit. I remember that Don has mentioned the direct exponential
voltage control of 3080's a long time ago, and while it was clear to me that

it could work in theory, I hesitated to consider it practically useful ...
until I saw the Small Stone schemos.
As fas as I understood it, the Iabc inputs of the all pass otas are driven
by
a *voltage*, while the trigger thresholds of the hysteretic switch are
sensing
the according *current*. So the modulation depth is temperature
compensated. Very nice indeed.

JH.



From jun at h-und-p.de  Thu Jul 23 11:10:41 1998
From: jun at h-und-p.de (jun at h-und-p.de)
Date: Thu, 23 Jul 98 11:10:41 CETDST
Subject: 74c150
Message-ID: <199807230910.JAA07840@hpser01.h-und-p.de >

Hi List,

in the schematics for the Serge TKB a 74c150 is used. This is  a 16 to 1
multiplexer (if I remember correctly). I checked a Farnell catalog and
they don't list it as available. Does anyone know of a possible source
for this or a suitable replacement part?

Cheers

Joerg



From sasami at blaze.net.au  Thu Jul 23 14:06:29 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Thu, 23 Jul 1998 22:06:29 +1000 (EST)
Subject: 74c150
Message-ID: <199807231206.WAA13866@blaze.net.au>

A possible solution would be to cascade a pair of 74c151 8 to 1 mux.
Any of the HC or HCT variants should drop in, assuming you can find them.

I use the LS variant myself, muxing the outputs of a top octave synthesizer
chip, then feeding them into a divider chain and another 8 to 1 mux, giving
me digitally selectable notes, much like they do in modern organs. I built
this back in the early eighties.

Ken

>in the schematics for the Serge TKB a 74c150 is used. This is  a 16 to 1
>multiplexer (if I remember correctly). I checked a Farnell catalog and
>they don't list it as available. Does anyone know of a possible source
>for this or a suitable replacement part?
>
>Cheers
>
>Joerg
>
>
_______________________________________________________________________
Ken Stone   sasami at blaze.net.au  
Catgirl Paradise <http://www.anime.net/~kens/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




From Chris.List at sc.siemens.com  Thu Jul 23 15:34:30 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 23 Jul 1998 09:34:30 -0400
Subject: 74c150
Message-ID: <81A062BC5305D111A9D700805F065968CE9474@maildepo.sc.siemens.com>

It's not an exact replacement, but the CD4069 is also a 16 to 1 mux -
that's what I used in my sequencer. CMOS, so it runs on 0 to 15v.

- CList

> -----Original Message-----
> From:	jun at h-und-p.de [SMTP:jun at h-und-p.de]
> Sent:	Thursday, July 23, 1998 7:11 AM
> To:	synth-diy at mailhost.bpa.nl
> Subject:	74c150
> 
> Hi List,
> 
> in the schematics for the Serge TKB a 74c150 is used. This is  a 16 to
> 1
> multiplexer (if I remember correctly). I checked a Farnell catalog and
> they don't list it as available. Does anyone know of a possible source
> for this or a suitable replacement part?
> 
> Cheers
> 
> Joerg



From pfperry at melbpc.org.au  Thu Jul 23 15:34:32 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 23 Jul 1998 23:34:32 +1000 (EST)
Subject: 74c150
Message-ID: <1.5.4.16.19961215061001.2b1ffbea@popa.melbpc.org.au>

At 11:10 AM 23/07/98 CETDST, Joerg jun at h-und-p wrote:
>in the schematics for the Serge TKB a 74c150 is used. This is  a 16 to 1
>multiplexer (if I remember correctly). I checked a Farnell catalog and
>they don't list it as available. 

it isn't listed in the 'multiplexer' list, but in the ttl section it has
DM74150N farnell number 373-059 which I imagine would work here, at least
worth checking the specs

paul perry melbourne australia

BTW are the Serge TKB schematics on the net anywhere?




From chordman at flash.net  Thu Jul 23 15:43:05 1998
From: chordman at flash.net (chordman at flash.net)
Date: Thu, 23 Jul 1998 15:43:05 +0200 (MET DST)
Subject: More Nonlinear
Message-ID: <199807231343.PAA07325@mailhost.bpa.nl>


Is nonlinear feedback in a filter viable?  I was thinking of 
the possibility of voltage controllable nonlinearity actually.

Perhaps something like a starved tube in the feedback path where
the starvation is voltage controlled.  Or perhaps a filter with
switchable nonlinearity elements in the feedback path, these 
elements may perhaps also be controlled by an external voltage.
Or would something like this just oscillate wildly or go 
randomly chaotic too easily?


-- Scott Gravenhorst
-- FatMan Site: http://www.teklab.com/~chordman
-- RedWebMail by <R<edStarWare





From msource68 at hotmail.com  Thu Jul 23 17:14:33 1998
From: msource68 at hotmail.com (Luis Otero)
Date: Thu, 23 Jul 1998 08:14:33 PDT
Subject: electric mistress
Message-ID: <19980723151434.22225.qmail@hotmail.com>

 My friend got an electric mistress from a freind and all the wires were 
pulled out and i have no idea where they go seeing how all the numbers 
are scaped off the chips. Does anyone have the info or know where I can 
get it. (and i mean every wire)


Thank lou


 

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com



From pfperry at melbpc.org.au  Thu Jul 23 18:09:12 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 24 Jul 1998 02:09:12 +1000 (EST)
Subject: More Nonlinear filter feedback
Message-ID: <1.5.4.16.19961215084446.2b0726fa@popa.melbpc.org.au>

At 03:43 PM 23/07/98 +0200, Scott Gravenhorst wrote:
>
>Is nonlinear feedback in a filter viable? 
....well yes...
so is nonlinear feedfoward, I suppose....
the analysis might be hairy though!
Where it is interesting is when the filter approaches oscillation, 
and limits. Under these circumstances, nonlinearities in the 
feedback path make all the difference.... see the Korg MS20
resonant filter for an example.

paul perry melbourne australia




From costello at seanet.com  Thu Jul 23 18:47:08 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 23 Jul 1998 09:47:08 -0700
Subject: More Nonlinear
References: <199807231343.PAA07325@mailhost.bpa.nl>
Message-ID: <35B7690B.938B688@seanet.com>

chordman at flash.net wrote:
> 
> Is nonlinear feedback in a filter viable?  I was thinking of
> the possibility of voltage controllable nonlinearity actually.
> 
> Perhaps something like a starved tube in the feedback path where
> the starvation is voltage controlled.  Or perhaps a filter with
> switchable nonlinearity elements in the feedback path, these
> elements may perhaps also be controlled by an external voltage.
> Or would something like this just oscillate wildly or go
> randomly chaotic too easily?

While walking around the University of Washington this past weekend
(it's interesting how thoughts are often tied to a place), I thought of
the same idea.  In some ways, I would think that there is some
nonlinearity in the feedback of many amplifiers - the Moog ladder
filter, for example, might have nonlinearities generated when the signal
feeds back to the other base of the differential pair, given enough
gain.

A clipping circuit in the feedback path would be simple, and would
create different effects based on the amount of feedback.  My idea was
to use a full-wave rectifier in the feedback path (AC coupled through a
capacitor), as this is a rather dramatic alteration of the sound.  A
paper I read on chaotic oscillations in music describes a test system
that used a full-wave rectifier in the feedback path; the result was a
period-doubling route to chaos.  I have NO idea what this would do in
the feedback of a filter, but it might be very interesting.  What would
this do to pole migration in the Moog filter, for example?  Could the
Moog filter then be used as a chaotic oscillator, given enough feedback
gain?  Or would the filter even oscillate?

The full-wave rectifier could be implemented with a single stage of an
LM3900, for full voltage control over the amount of rectification (see
Serge Tcherepnin's patents at http://www.patents.ibm.com for
clarification).  Several stages could be cascaded. 

A question:  Can an LM3900 be used as a differential amplifier, running
off of a single-ended power supply?  

Later,

Sean Costello



From ebarbour at svetlana.com  Thu Jul 23 18:48:15 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 23 Jul 1998 09:48:15 -0700
Subject: More Nonlinear
Message-ID: <01BDB61F.03EAC1C0.ebarbour@svetlana.com>

>Perhaps something like a starved tube in the feedback path where
>the starvation is voltage controlled.

This would be a perfect application for my pentode VCA........

>Or would something like this just oscillate wildly or go 
>randomly chaotic too easily?

Depends on the loop gain and pole-zero layout. A peak or 180
deg phase shift at any frequency (other than the desired Fo)
would tend to be unstable and oscillate at that freq.

It's a problem when you have capacitive
coupling between multiple stages in state-variable or biquad filters. If there
was only one stage with C coupling, it will probably not happen.

Besides, maybe it would be an interesting effect........

Eric Barbour
Svetlana Electron Devices





From costello at seanet.com  Thu Jul 23 20:17:02 1998
From: costello at seanet.com (Sean Costello)
Date: Thu, 23 Jul 1998 11:17:02 -0700
Subject: More Nonlinear filter feedback
References: <1.5.4.16.19961215084446.2b0726fa@popa.melbpc.org.au>
Message-ID: <35B77E1E.3FF5A4DB@seanet.com>

Paul Perry wrote:
> 
> At 03:43 PM 23/07/98 +0200, Scott Gravenhorst wrote:
> >
> >Is nonlinear feedback in a filter viable?
> ....well yes...
> so is nonlinear feedfoward, I suppose....
> the analysis might be hairy though!
> Where it is interesting is when the filter approaches oscillation,
> and limits. Under these circumstances, nonlinearities in the
> feedback path make all the difference.... see the Korg MS20
> resonant filter for an example.

Having no MS20 filter to play with (although I have 2 LM13700's that I
might use to create a rather inaccurate clone), I am curious.  Can you
describe the effect of the diodes in the feedback opamp of the MS-20
filter, from an aesthetic perspective?  Or from an electronic
perspective?  Also, is there any differential amp distortion in the
MS-20 from the inputs of the LM13600's, or are the signal levels too
low?

Thanks,

Sean Costello



From Chris.List at sc.siemens.com  Thu Jul 23 20:23:42 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 23 Jul 1998 14:23:42 -0400
Subject: Revised www site & LM1036 Audio Processor Module
Message-ID: <81A062BC5305D111A9D700805F065968CE9478@maildepo.sc.siemens.com>

Hi all -

I've just completed the first pass of my new and improved www site -
"Synth-Builder's Online Resource".
"Oh no, not another one!" moans the crowd! Yes, another one. What we
say, the internet has provided for a golden renaissance of home brew
synthesis devices and we all want to share the love :). Soon to be
posted will be all of my vectorboard layouts and faceplates designs as
well as some more complete module descriptions. You'll also find many of
your own pages listed in the links section (let me know who I've
missed).

Anyway, there's not too much new or different here, but in the Circuits
section, you will find full description / schems / faceplate, etc., for
my new "LM1036 Audio Processor" module. From the introduction;

"National Semiconductor's LM1036 was designed for use as a volume, pan,
and tone control chip for consumer electronics. It's a nice little chip
that seems to have gone largely unnoticed by the synth building
community. The fact that all inputs and outputs use voltages rather than
currents makes it very simple to use, and the fact that it attenuates
normal level input signals rather than amplifying tiny ones helps keep
noise to a minimum. The chip can be use to pan a single input to two
outputs or to x-fade
two inputs signals to a single output."

(thanks go to Batz for recommending this fine little chip to me)

Check it all out here;
http://www.mindspring.com/~clist

- CList



From tomg at vivid.net  Thu Jul 23 20:35:26 1998
From: tomg at vivid.net (tomg)
Date: Thu, 23 Jul 1998 13:35:26 -0500
Subject: electric mistress
In-Reply-To: <19980723151434.22225.qmail@hotmail.com>
Message-ID: <yam7508.1312.118864792@mail.vivid.net>

On 23-Jul-98, Luis Otero wrote:
> My friend got an electric mistress from a freind and all the wires were 
>pulled out and i have no idea where they go seeing how all the numbers 
>are scaped off the chips. Does anyone have the info or know where I can 
>get it. (and i mean every wire)


>Thank lou


Is it the 2 X 9V battery type or the transformer? I have schemo's for both I
could scan and send. 

-Tom




From tomg at vivid.net  Thu Jul 23 20:46:27 1998
From: tomg at vivid.net (tomg)
Date: Thu, 23 Jul 1998 13:46:27 -0500
Subject: 74c150
In-Reply-To: <1.5.4.16.19961215061001.2b1ffbea@popa.melbpc.org.au>
Message-ID: <yam7508.1375.118864792@mail.vivid.net>

On 23-Jul-98, Paul Perry wrote:
>At 11:10 AM 23/07/98 CETDST, Joerg jun at h-und-p wrote:
>>in the schematics for the Serge TKB a 74c150 is used. This is  a 16 to 1
>>multiplexer (if I remember correctly). I checked a Farnell catalog and
>>they don't list it as available. 

>it isn't listed in the 'multiplexer' list, but in the ttl section it has
>DM74150N farnell number 373-059 which I imagine would work here, at least
>worth checking the specs

>paul perry melbourne australia

>BTW are the Serge TKB schematics on the net anywhere?

Sean put this up on the 16th.

-Tom

Hi all:

Music Machines now has a few select Serge & Buchla schematics.  Go to
http://www.hyperreal.org/music/machines/schematics.html and check out
the schematics for the Buchla Lopass Gate, the Serge TKB, and the Serge
Waveshaper.

Later,

Sean Costello




From J20333 at aol.com  Thu Jul 23 21:36:37 1998
From: J20333 at aol.com (J20333 at aol.com)
Date: Thu, 23 Jul 1998 15:36:37 EDT
Subject: un subscribe me
Message-ID: <5b831c33.35b790c7@aol.com>

take me off this list



From verbos at on-q.com  Thu Jul 23 21:48:11 1998
From: verbos at on-q.com (mark verbos)
Date: Thu, 23 Jul 1998 13:48:11 -0600
Subject: original and ingenious circuits ... (was: in How the heck doe
		s the MS-50 filter WORK?)
References: <81A062BC5305D111A9D700805F065968CE9469@maildepo.sc.siemens.com>
Message-ID: <35B7937B.C65F7C9@on-q.com>



List, Christopher wrote:

> Actually, one of my favorites was one you told me about! The ARP (I
> beleive that's who it was) cv quantizer. I had always been thinking that
> the way to quantize was to run the input through a ADC then to a DAC
> with the low bits disconnected - this gets very expensive very quickly
> if you want multiple channels. The ARP method, OTOH, uses a fixed
> frequency stepped voltage oscillator (that could be made from - among
> other things - a counter and a DAC) to drive a comparator + S&H. As soon
> as the input voltage crosses the stepped voltage, you sample and hold
> the stepped voltage at the output. You can have as many channels as you
> want, just by adding more comparator + S&H elements connected to the
> same stepped voltage! That's cool!
>
>

anybody have this schematic?

--
mark verbos

"I think the future of analog modulars is to build them yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
  "No Good Reason" on Thrust, NYC
  "High Metabolism" on A.F.U., Germany





From ebarbour at svetlana.com  Thu Jul 23 23:09:54 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Thu, 23 Jul 1998 14:09:54 -0700
Subject: MIDI for a Hammond
Message-ID: <01BDB643.919706E0.ebarbour@svetlana.com>

>Is there any info on converting a Hammond tone generator organ to MIDI
>control? 

Bill:
Don't forget to look at the "MIDI-To-Anything" web page:

http://www.calpoly.edu/~cwoodwor/midi.html

It lists NUMEROUS MIDI-to-relay driver devices.

Personally I like the JW Electronics MTP-1.
It's the cheapest, a mere 86 bucks;
has 32 outputs, is nice and small and simple,
and has a built-in supply regulator so it
can run from 7 to 35 vdc.

http://www.warwick.ac.uk/~essfc/mtp1.html

In fact, it's so good that I'm going to use it to control my 
tube synthesizers. One can operate a ladder of trimpots
from the relay outputs to get an ARBITRARY CV scale
out of it. And run ANY kind of VCO. Linear, exponential,
what have you............it's no longer necessary to fight
around with thermistors to make a usable synth.........

Eric Barbour
Svetlana Electron Devices





From LEG at btinternet.com  Thu Jul 23 23:13:19 1998
From: LEG at btinternet.com (george & lorraine)
Date: Thu, 23 Jul 1998 22:13:19 +0100
Subject: CEM memory loss!
Message-ID: <01bdb67e$b78f5380$LocalHost@windows95>

Hi all
Many thank's for info:(will sort out address book one day!!!).Only slightly the worse for red wine!(seemed better option in the end).

Live long and prosper

George


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From gur-m at internet-zahav.net  Thu Jul 23 21:25:40 1998
From: gur-m at internet-zahav.net (Gur Milstein)
Date: Thu, 23 Jul 1998 21:25:40
Subject: ADV-BASS
Message-ID: <3.0.2.16.19980723212540.2ec7997e@mail.internet-zahav.net>

hi guy's.
i'm looking for  some drums for my system,so i'm
thinking about the ADV BASS frome MAP.
so  i want to ask the guy's that build this how
is it sound,is it power full,and can it be sound like the 808
or 909 bass drums ?

thanx
Gur Milstein



From b.layer at vikingelectronics.com  Thu Jul 23 23:41:21 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 23 Jul 1998 16:41:21 -0500
Subject: MIDI for a Hammond
In-Reply-To: <01BDB643.919706E0.ebarbour@svetlana.com>
Message-ID: <3.0.5.32.19980723164121.007b0c10@192.168.210.18>

>Bill:
>Don't forget to look at the "MIDI-To-Anything" web page:
>
Wow! I had no idea that the page existed... I'm still pretty new to this
internet stuff.

>Personally I like the JW Electronics MTP-1.
>It's the cheapest, a mere 86 bucks;
>has 32 outputs, is nice and small and simple,
>and has a built-in supply regulator so it
>can run from 7 to 35 vdc.
>
Neat, but how are the outputs controlled? A typical MIDI kbd has 4 octaves,
so counting black keys, this certainly presents more than 32 possibilities.
Just what does the JW unit support?
>
>In fact, it's so good that I'm going to use it to control my 
>tube synthesizers. One can operate a ladder of trimpots
>from the relay outputs to get an ARBITRARY CV scale
>out of it. And run ANY kind of VCO. Linear, exponential,
>what have you............it's no longer necessary to fight
>around with thermistors to make a usable synth.........
>
Heresy in the house of Thermionics! But what a cool idea. All one would
need to do is to construct a 'tuning' box with pitch controls for each note
supported... I liked what you did to the
generic-Japan-plastic-nightmare-cheezo-whatever synth that you used for
your TS-10 controller, but this seems more like the way to go. No loss of
control whatsover, but I doubt pitch bend or mod wheel data could be
implemented. Or...

If the 'tuning' box were to have a pitch wheel on it, that would work, I
beleive. What you think?


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From tomg at vivid.net  Thu Jul 23 23:51:13 1998
From: tomg at vivid.net (tomg)
Date: Thu, 23 Jul 1998 16:51:13 -0500
Subject: More Nonlinear
In-Reply-To: <35B7690B.938B688@seanet.com>
Message-ID: <yam7508.666.118809928@mail.vivid.net>

On 23-Jul-98, Sean Costello wrote:

>A question:  Can an LM3900 be used as a differential amplifier, running
>off of a single-ended power supply?  

Nationals app notes has a diff-Tachometer and diff-integrator. Looks like a
diff-amp would be easy, but no examples.

-Tom








From Chris.List at sc.siemens.com  Thu Jul 23 23:59:38 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Thu, 23 Jul 1998 17:59:38 -0400
Subject: FW: 74c150
Message-ID: <81A062BC5305D111A9D700805F065968CE9482@maildepo.sc.siemens.com>

Whoops!

You are correct sir!

Make that a CD4067.

- CList

> -----Original Message-----
> From:	sasami at blaze.net.au [SMTP:sasami at blaze.net.au]
> Sent:	None
> To:	List, Christopher
> Subject:	RE: 74c150
> 
> >It's not an exact replacement, but the CD4069 is also a 16 to 1 mux -
> >that's what I used in my sequencer. CMOS, so it runs on 0 to 15v.
> 
> 4069 is a hex buffer :(
> 
> Ken
> 



From pfperry at melbpc.org.au  Fri Jul 24 02:50:11 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 24 Jul 1998 10:50:11 +1000 (EST)
Subject: More Nonlinear filter feedback
Message-ID: <1.5.4.16.19961215172539.399f21b8@popa.melbpc.org.au>

At 11:17 AM 23/07/98 -0700, Sean Costello  wrote:

>  Can you
>describe the effect of the diodes in the feedback opamp of the MS-20
>filter, from an aesthetic perspective? 
....there is quite a bit of harmonic generation here...
when the 2 sections are set oscillating you can get a didgeriou effect
(first filter around 100Hz, sweep second around at a higher freq)
When oscillating, the filters will lock together if too close in freq.

 Or from an electronic
>perspective?
......???????.... but, a compression type ckt in a positive feedback
loop I suppose still acts as a compressor...

 Also, is there any differential amp distortion in the
>MS-20 from the inputs of the LM13600's, or are the signal levels too
>low?
....they are low, but I havn't compared with LM13700 which are very hard
to get in Australia
>
paul perry melbourne australia




From JWBarlow at aol.com  Fri Jul 24 03:10:57 1998
From: JWBarlow at aol.com (JWBarlow at aol.com)
Date: Thu, 23 Jul 1998 21:10:57 EDT
Subject: Serge TKB
Message-ID: <7605faf1.35b7df22@aol.com>



>Music Machines now has a few select Serge & Buchla schematics.  Go to
>http://www.hyperreal.org/music/machines/schematics.html and check out
>the schematics for the Buchla Lopass Gate, the Serge TKB, and the Serge
>Waveshaper.

I'm wondering if this is still a prototype model since it is missing the all
important "Keyboard Pressure" control voltage output. I also noticed a few
differences between the Waveshaper schematic and the "production" Waveshaper,
but these may not be of significance.

Are the LM 3900 application notes available on line?

John B.



From tomg at vivid.net  Fri Jul 24 03:40:27 1998
From: tomg at vivid.net (tomg)
Date: Thu, 23 Jul 1998 20:40:27 -0500
Subject: More Nonlinear
In-Reply-To: <yam7508.666.118809928@mail.vivid.net>
Message-ID: <yam7508.1387.118811448@mail.vivid.net>

On 23-Jul-98, tomg wrote:
>On 23-Jul-98, Sean Costello wrote:

>>A question:  Can an LM3900 be used as a differential amplifier, running
>>off of a single-ended power supply?  

>Nationals app notes has a diff-Tachometer and diff-integrator. Looks like a
>diff-amp would be easy, but no examples.

>-Tom

Wrong book!

National App Notes Vol 1, AN72-1O Fig 25: Shows a gnd ref diff amp.

V1 - inv-input  - 1OM Ri / 1OM Rf / 1.5M +V
V2 - non-input  - 1OM Ri / 1OM gnd / 1.5M +V
output          - diode anode / cathode to 1OM Rf / Rl = 1OK
 
Common mode biasing to allow V1 & V2 to vary over a +1V to -13V
range(looks odd to me too..) when operated from a +15V supply.

-Tom



 









From chordman at flash.net  Fri Jul 24 03:49:40 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 24 Jul 1998 01:49:40 GMT
Subject: More Nonlinear filter feedback
In-Reply-To: <1.5.4.16.19961215172539.399f21b8@popa.melbpc.org.au>
References: <1.5.4.16.19961215172539.399f21b8@popa.melbpc.org.au>
Message-ID: <35bbe724.90778460@mail.lan>

Another question:

What kind of difference in effect can I expect by using a single pole
filter as opposed to a state variable filter (both VC cutoff) using
nonlinear feedback?

Also, in the case of the state variable, there are two feedback paths,
one for the first integrator itself and the other from the second
integrator back to the first integrator's input.  Where would the
nonlinear element be best placed?  Or is this "Dr. Mad Scientist"
time? (again)  Hmmm.  I think I know the answer here, but I'll let the
question stand.


-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From martin.czech at intermetall.de  Fri Jul 24 07:26:30 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 24 Jul 1998 07:26:30 +0200 (MET DST)
Subject: synth diy archive
Message-ID: <199807240526.HAA04523@window.intermetall.de>

> does anyone know what has happened to the index synth diy?
> 
> . my request was answered with "no files available"
> regards
> geoff james
> 
> 
yeah, it's not working. I'm currently trying to get a substitute
and I have to write some software for this purpose. Patience ...

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 sky36919 at skynet.be  Fri Jul 24 08:43:48 1998
From: sky36919 at skynet.be (Hugo Haesaert)
Date: Fri, 24 Jul 1998 08:43:48 +0200
Subject: 74c150
In-Reply-To: <1.5.4.16.19961215061001.2b1ffbea@popa.melbpc.org.au>
Message-ID: <199807240644.IAA25411@papagena.skynet.be>

Hi Joerg, Paul and List !

The schemos for the TKB are at :

http://www.hyperreal.org/music/machines/manufacturers/Serge/schematic
s/

The 74c150 is still listed in the catalogue from a local electronics 
shop in Brussels Belgium . BEF 360, about DEM 18 or usd10 .

As this ic is part of the touchKBD and not the sequencer proper,  i 
suspect (gut feeling :) that using ttl for this is not on .  

Those keys, anyone with an explanation how these work here ?

Also, the pots are "fed" a voltage from two 4051's, why no 74c150 ?

Inversely, why no two 4051 for the kbd ?

My 1977 National cmos databook does not list the 4067 .  Did this 
part exist when the TKB was first built ?

More questions than answers :)

Keep 'em oscillating :)

Hugo
=



From Robert.Schrum at harpercollins.com  Fri Jul 24 16:57:00 1998
From: Robert.Schrum at harpercollins.com (Robert Schrum)
Date: Fri, 24 Jul 1998 10:57:00 -0400
Subject: AW: Midi Hammond
Message-ID: <0005B50D.CE21411@harpercollins.com>

Most of the "features" that define the Hammond's sound are accidental, such as
key click or the mentioned velocity/pressure sentitivity.  The key click (that
Hammond tried to filter out only to hear complaints about the loss of
articulation) is merely contact noise impacting the relatively small signal
coming out of the generator coils.

I recently tried various keys on a well-worn studio B3 and my like-new X5 at
home.  When you depress a key slowly, there is no definite pattern to how the
nine harmonics come in on either organ.  When they do come in, the're really
grungy, as It's consistent for the same key, but not for the next.  It's
basically dependent on the amount of wear or bend that exists in each of the key
contact wires or buss bars.  I've never encountered pressure-sensitivity per-se
(a'la aftertouch) on a Hammond that was in condition worth playing.  The only
time you'd get this is if the keyboard wires or bars were really trashed.

The other thing that I have never even encountered in a MIDI hammond emulation
is the fact that Hammond keys bounce if released very quickly. (Remember Steve
Miller's "Fly Like an Eagle?")  Likewise, each successive bounce contacts fewer
harmonics.  You could bring this in on the upper end of release velocity values.

The switching device at each keying node would have to operate just like a
switch--either on or off (remember On-resistance must be sub-ohm!  DIP/reed
relays?)  If the devices switch on at a specific voltage threshold (like a
Schmitt trigger) just feed each one with slightly mismatched resistors with a
signal whose rising slope varies with note velocity.  Sum a little noise to add
contact bounce as the control voltages approaches and passes the thresholds, and
a 6-10Hz sine at release velocities above 100 or so.  Part count's getting
pretty $teep for a non-computer modeled solution, though (549 switches per
manual! :o )





-----Original Message-----
From: "Bill Layer" <b.layer at vikingelectronics.com> at hcinternet-server
Sent: Wednesday, July 22, 1998 12:55 PM
To: Haible Juergen <Juergen.Haible at nbgm.siemens.de> at HCINTERNET-SERVER
Cc: synth-diy at mailhost.bpa.nl at HCINTERNET-SERVER
Subject: RE: AW: Midi Hammond


At 12:30 PM 7/22/98 +0200, you wrote:
>
>       >The individual harmonics are
>       >not progressive as the note is pressed; they all contact at roughly
>the same
>       >time.
>
What?

>Hmm, I don't own a Hammond, but I used to own a Farfisa, which also
>had a lot of separate contacts under each key. And at least here,
>with this VIP 345, it made a great difference how fast you played
>the keys. Depressing a key slowly, one could clearly hear the harmonics
>come in one by one. While this is not exactly your standard playing
>style, it still demonstrates that you *can* phrase individual notes
>differently.

I must agree. I'm no Hammond expert, but I was under the impression (from
my Hammond-palying friends) that the ability to control note phrasing with
key pressure is a major feature of the Hammond tone wheel series. On my
humble M-3, I can very deliberately control the fullness of voice by
playing gently or firmly. This is especially apparent when using the
percussion voice.

My simple concept for controlling fullness with the MIDI 'initial key
pressure' message involves direct corrolation/quantization of the pressure
value to the number of harmonics to be included in the note. A hard
keypress would fold in all harmonics, while a moderate keypress would fold
in fewer harmonics, and a light touch might deliver only the fundamental etc..

Seems like it could work.


------------------------------
Bill Layer
Sales Technician

Viking Electronics, Inc.
1531 Industrial St.
Hudson, WI 54016

Phone: (715)386-8861 Ext. 210
Fax: (715)386-4344
E-mail: b.layer at vikingelectronics.com

http://www.vikingelectronics.com
24 Hour Fax Back System: (715)386-4345



From Robert.Schrum at harpercollins.com  Fri Jul 24 18:59:00 1998
From: Robert.Schrum at harpercollins.com (Robert Schrum)
Date: Fri, 24 Jul 1998 12:59:00 -0400
Subject: MIDI for a Hammond
Message-ID: <0005B813.CE21411@harpercollins.com>

Out of curiosity, I got out my trusty 13-trace 'scope and tried it out.  ;)
(actually, I simulated it in Microsoft Excel)

The attached image time-graphs a note pressed very slowly and released very
quickly. The velocity-controlled keying voltage, noise and release bounce LFO
are shown separately, summed with the noise attenuated, and fed into 9 Schmitt
triggers with slightly different thresholds, which represent the 9 key contacts
on the 9 keyboard harmonic bus bars (labeled as the traditional pipe-organ
footages appear on the drawbars).

The main difficulty here is obviously in trying to simulate the nuances of an
extremely simple mechanical system with an electronic one.  Noise simulates dirt
and rough contact surfaces.  Attack and release slope simulates time required
for key to travel.  Differing trigger thresholds simulate differences in
tolerance and geometry of key contact wires and bars.  Release LFO simulates key
bouncing off rubber stops.  The problem is, all these things contribute greatly
to the sound of the beast.  If you could simultaneously create up to 61 of those
summed controlling voltages per manual (4th trace) with a CPU, the keying
part-count would be reduced to just 549 switching devices and maybe those
slightly-mismatched resistors if the switchers aren't inconsistent enough.

(I'll have to suggest that release bounce to Dave Amels for the next revision of
his Voce V3 module's firmware.  I already asked him for a MIDI controller
assignment to "turn the power switch off and on" (very cool and unique pitch and
gain structure changes as the tonewheels and preamp lose and regain power.)
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From ebarbour at svetlana.com  Fri Jul 24 19:35:34 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Fri, 24 Jul 1998 10:35:34 -0700
Subject: midi controls
Message-ID: <01BDB6EE.CB04C100.ebarbour@svetlana.com>


>Neat, but how are the outputs controlled? A typical MIDI kbd has 4 octaves,
>so counting black keys, this certainly presents more than 32 possibilities.
>Just what does the JW unit support?

You tell Mr. Wale which MIDI key-down code you want for the first
relay output (60=middle c). He programs it into the PIC processor.
The 32 outputs are then sequential up from
that keycode............each goes low when you press
the corresponding key. No support for pitch bend or suchlike,
since old organs don't do that....two or more units can be chained
together so you can get more than 32 outputs. The chained
units obviously have to be programmed for the keycodes you want
them to respond to.

>If the 'tuning' box were to have a pitch wheel on it, that would work, I
>beleive. What you think?

It would be easy to make up an external analog-control pitchbend
wheel or lever. For that matter, does anyone know of an OFF-THE-SHELF
separate pitchbend control with springloading to return it to center?


Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From b.layer at vikingelectronics.com  Fri Jul 24 19:53:42 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 24 Jul 1998 12:53:42 -0500
Subject: WARNING **** LIST CRASH ****
Message-ID: <3.0.5.32.19980724125342.007c7bc0@192.168.210.18>

All,

Uh, methinks the list be crashed... I'm getting all kinds of mail from the
cubase list (BTW, nice to see that they are not immune from internal
conflict..). 

Last hour I received 115 messages about cubase stuff!!!

Is anyone else having this problem?
Bill Layer - St.Paul, MN.
Tubes, tubes, tubes.




From clark at andrews.edu  Fri Jul 24 20:09:42 1998
From: clark at andrews.edu (Tony Clark)
Date: Fri, 24 Jul 1998 14:09:42 -0400 (EDT)
Subject: WARNING **** LIST CRASH **** - Not Really
In-Reply-To: <3.0.5.32.19980724125342.007c7bc0@192.168.210.18>
Message-ID: <Pine.SOL.3.91.980724140740.3151B-100000@edmund.cs.andrews.edu>

> Uh, methinks the list be crashed... I'm getting all kinds of mail from the
> cubase list (BTW, nice to see that they are not immune from internal
> conflict..). 
> Last hour I received 115 messages about cubase stuff!!!

   Most likely your name got added to their list somehow?  I haven't seen 
a single Cubase post in my mail all day and hope I don't!  ;)
   Is the Cubase list coming out of mailhost.bpa.nl?

   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 thudson at cygnus.com  Fri Jul 24 20:44:22 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Fri, 24 Jul 1998 14:44:22 -0400
Subject: midi controls
References: <01BDB6EE.CB04C100.ebarbour@svetlana.com>
Message-ID: <35B8D606.9E4CA6@cygnus.com>

Eric Barbour wrote:
> It would be easy to make up an external analog-control pitchbend
> wheel or lever. For that matter, does anyone know of an OFF-THE-SHELF
> separate pitchbend control with springloading to return it to center?
> 
Anatek had a small device in their "Pocket MIDI" series that
transmitted continous controller and had a phone jack so
you could plug in footpedal, joystick, etc. 

I think Musicians Friend carries them...

Thomas



From tomg at vivid.net  Fri Jul 24 20:47:21 1998
From: tomg at vivid.net (tomg)
Date: Fri, 24 Jul 1998 13:47:21 -0500
Subject: electric mistress
In-Reply-To: <19980723212151.6931.qmail@hotmail.com>
Message-ID: <yam7509.1064.118880016@mail.vivid.net>


I'll put the schemo's on line for everyone who want 'em.

-Tom




From b.layer at vikingelectronics.com  Fri Jul 24 22:14:25 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 24 Jul 1998 15:14:25 -0500
Subject: My list crash panic
Message-ID: <3.0.5.32.19980724151425.007cba90@192.168.210.18>

All,

Well, it musta been a transient glitch. No more spams today. Thnaks for
those who provided feedback.

Bill Layer - St.Paul, MN.
Tubes, tubes, tubes.




From magnus at analogue.org  Fri Jul 24 22:19:48 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Fri, 24 Jul 1998 22:19:48 +0200
Subject: SH-1000 LFO
In-Reply-To: Your message of "Thu, 23 Jul 1998 16:38:13 +1000 (EST)"
References: <1.5.4.16.19961214231342.38ef689c@popa.melbpc.org.au>
Message-ID: <199807242019.WAA18727@piraya.electrum.kth.se>

>>>>> "PP" == Paul Perry <pfperry at melbpc.org.au> writes:

 >>> The LFO on the SH-1000 is built with three normal transistors, one FET
 >>> and one weird thingie which looks like a tranny, but has the symbol of
 >>> a diode with three legs (?) 
 >> 
 PP> my guess is a unijunction transistor (UJT) widely used at this period
 PP> for oscillators (eg in the notorious 'Stylophone')

It ougth to be a SCR, a PNPN junction which you can start with the
extra leg and turn off by reversing the voltage over it. You can get
one by taking a CMOS chip, use the Vss and Vcc as the diod legs and a
input as the extra leg.

Have fun!

Cheers,
Magnus





From moxie at idonex.se  Sat Jul 25 00:47:40 1998
From: moxie at idonex.se (Johan Gustavsson)
Date: Sat, 25 Jul 1998 00:47:40 +0200 (MET DST)
Subject: SH-1000 LFO
Message-ID: <199807242247.AAA27812@jolt.idonex.se>

Well, thank you everybody for all your help in finding out what my
mystery component is! Everybody was saying either UJT (which seemed to
match better, functionwise) or SCR (which matches the symbol
description). None of them looked right, though, and I still couldn't
find any similar circuits to mine that I could peruse for hints on
what was wrong. Mind you, I'm not very good at electronics at all, so
I decided to get myself a good allpurpose textbook on the subject.
After all, I do have a registered music electronics company in Sweden
(consisting of me and my friend Olof, playing around, mainly :-> ), so
perhaps I ought not to be a complete ignoramus...

Since everybody seems to be raving about "The art of Electronics" I
thought, "Oh, well", and went to an online bookstore and ordered. It
arrived today, I leafed a bit and then went to the index..."Hm, let's
see: Relaxation oscillator and, oh, UJT, then" and the first page I
look at has "my" component on it, in a configuration that looks rather
similar to the one in the synth! Turns out the correct answer is PUJT,
Programmable Uni-Junction Transistor...

This book really is amazing! Ok, so I know just about nothing
electronicswise (I know what a transistor looks like, but I couldn't
tell you which leg is Base, and I've no idea what it does), yet some
leafing later I'm able to look at small parts of the SH-1000 schemo
and go "Oh, so this thing switches on at a treshold voltage set by
those resistors, and...yes, that means it should go full swing". I'll
be reading this *a lot* during the coming week, I can tell you...And
then show me the synth that can resist my newfound analyzing powers
:-)

Anyway, thanks for pointing me in the right direction. I will return
with more focused questions when I've understood some more :-) Now, if
my upstairs neighbours could finish their loud-music-and-drunken-
shouting-party, then I could go to sleep...Ah, the joys of student
housing :-)

/Moxie (Wide awake in the middle of the night)

PS. Just had to share this little gem with you, from an absolutely
hilarious flame from Mr Roommate:

>> Matt, you're only looking silly doing this. Do yourself a favour

> HEY LEARN TO SPELL YOU FUCKING SCANDANAVIAN POOF -  THAT ONE IS THREE WORDS
> AT A TOTAL OF 23 LETTERS -  IT'S F-A-V-O-R

(The counting, of course, refers to my mention of "Four-letter words"...)




From synth1 at airmail.net  Sat Jul 25 01:06:12 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Fri, 24 Jul 1998 23:06:12 -0000
Subject: DIY Grab-bag for sale
Message-ID: <01BDB757.A7EFF2C0@dal25-25.ppp.iadfw.net>

Just about to finish undigging from the move to the new lab. In
the process, I have a big box full of random parts, cables, bits,
pieces, etc. No SSM/CEM, 726s or Buchla modules, but plenty
of DIY stuff. Some data books! Most parts are new, never used.
Old, but never used (some left over from Tandy MG-1 days).

Send private bid: sorry, US shipping only (customs would puke
if they ever opened this!). Min bid is $25 to cover postage/handling.

Bids end Monday AM when I ship it out. Wife's orders.

Paul Schreiber
Synthesis Technology






From magnus at analogue.org  Sat Jul 25 01:15:17 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 25 Jul 1998 01:15:17 +0200
Subject: AW: original and ingenious circuits ... (was: in How the heck does the MS-50 filter WORK?)
In-Reply-To: Your message of "Thu, 23 Jul 1998 12:18:55 +0200"
References: <1BF5E20E0C4DD111BBAB00805FE2D5828977DC@nbgm336a.nbgm.siemens.de>
Message-ID: <199807242315.BAA20112@piraya.electrum.kth.se>

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

Hi!

 HJ> 	[great description of Eventide omitted]

 >> The LFO in the EH SmallStone is a nice one as well, it is based around
 >> one CA3094. Hell, I like the rest of the SmallStone as well, I just
 >> lack a few features...

 HJ> Very nice circuit. I remember that Don has mentioned the direct
 HJ> exponential voltage control of 3080's a long time ago, and while
 HJ> it was clear to me that it could work in theory, I hesitated to
 HJ> consider it practically useful ... until I saw the Small Stone schemos.

 HJ> As fas as I understood it, the Iabc inputs of the all pass otas
 HJ> are driven by a *voltage*, while the trigger thresholds of the
 HJ> hysteretic switch are sensing the according *current*. So the
 HJ> modulation depth is temperature compensated. Very nice indeed.

The allpass connection is a nice one as well, one easy falls into
considering OTAs and op-amps mixed up to form a filter, not too
unsimilar the ASM-1 VCF BTW. The CA 3094's output transitors forms the
buffer needed in a neat and compact way. The relative freedom of the
output transistor is certainly used in the LFO.

In the LFO is the 1M pot being feeded with a 5.9 k and 2 V source and
is looking into the Vbe of the diff-pair current transistor. I guess
it would not be too difficult to make this thing track a CV.

Also note the clever use of the Color switch, someone has surely done
a case study to get the most out of it.

I have been long considering cloning the SmallStone since I don't want
to wreck the one that I have with all the mods. Some of my ideas
involves:

Width of modulation, thus the range for which the LFO sweeps (I will
save depth for later). Replacing the 100 resistor from the LFO with a
pot should do the trick.

Depth of modulation, thus the dry/wet mix between the phase core and
input signal. This mix is being performed by a fixed 30k/27k network
which could be altered with a pot to source the 27k resistor.

Color of modulation, thus the sharpness. This is being perfomed by a
3k3/4k7 divider feeding the core output to the input. Replacing with a
5k pot should work. The colour mode makes this a very wet unit...

One distinct property of the SmallStone in colour mode is that when it
sweeps down in frequency to reach the very bottom it will let some
higher frequencies in, so when running white or pink noise throught it
you get a windy noise which "fries" as it reach the bottom, Jarre has
used it and I discovered it by misstake myself! Taking this to an RTA
is a great enjoymment, you have waves squashing here and there on you
RTA display at the same time as you hear them, it kind of fits while
it makes a very cool effect :) I got to get a RTA again, I used to
borrow a DN-60 and misses it a lot with all it's brokeness.

CV input for modulation offset. Still considering on how to make this
mod go into minimalistic mode, that is, without needing an op-amp. If
using a breaking jack one could split away the cap in the LFO and
insert the CV and thus reuse the buffer in the LFO if one does not
trust the signal to be low-impedance enought. This should be combined
with some measure to turn of the current output, this can be done by
forcing the pin 5 contol to ground. It is a bit ugly, but it should do
the trick....

I have been considering an offset pot, so that one can position the
point around which the effect sweeps.

Another thing one might want to try out is a core depth switch
basically selecting which of the core outputs that is going to be used
for output. This would make it become similar to the Formant 24 db
filter which has such a switch.

So, without adding more silicon this cursuits lends itself to further
experimentations, or at least so does it seems.

In some notes that I have made I have a derivation of the allpass
properties that the core has as a function of components and Iabc
current. I could dig it up.

One of the things that I really like is the sonical appearance of this
thing.

Cheers,
Magnus



From magnus at analogue.org  Sat Jul 25 01:25:46 1998
From: magnus at analogue.org (Magnus Danielson)
Date: Sat, 25 Jul 1998 01:25:46 +0200
Subject: More Nonlinear
In-Reply-To: Your message of "Thu, 23 Jul 1998 09:48:15 -0700"
References: <01BDB61F.03EAC1C0.ebarbour@svetlana.com>
Message-ID: <199807242325.BAA20173@piraya.electrum.kth.se>

>>>>> "EB" == Eric Barbour <ebarbour at svetlana.com> writes:

Hi!

 >> Perhaps something like a starved tube in the feedback path where
 >> the starvation is voltage controlled.

 EB> This would be a perfect application for my pentode VCA........

This made me think... if one fiddle around with the upper grids of a
pentode, wouldn't you be able to somehow modulate the nonlinearness.
This is just a idea based on my very basic knowledge of tubes...
Why not use the secondary emission for instance as a effect rather
than a defect?

Cheers,
Magnus



From chordman at flash.net  Sat Jul 25 01:49:12 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Fri, 24 Jul 1998 23:49:12 GMT
Subject: More Nonlinear
In-Reply-To: <199807242325.BAA20173@piraya.electrum.kth.se>
References: <01BDB61F.03EAC1C0.ebarbour@svetlana.com> <199807242325.BAA20173@piraya.electrum.kth.se>
Message-ID: <35c41ba7.169769781@mail.lan>

Ok, this weekend is "nonlinear feedback filter mad scientist" weekend.
I've decided on a state variable filter because it can be converted
easily to a simple single pole LP filter with an SPST switch.  It also
has two feedback paths to mess up with nonlinearities.  I've come up
with 5 or 6 simple nonlinear devices that I can patch in to test.  I
will be using an LM13600 for the OTAs.  For now, I will control the
nonlinear stuff with a simple pan pot to pan between a linear path and
a nonlinear one or maybe two different nonlinear paths, but if it
sounds wierd/good, I will eventually devise some kind of VC panning
system.

Heck, I need another filter anyway.

Wish me luck, and if I get usable results, I'll put the schemos on my
FatMan site.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From tomg at vivid.net  Sat Jul 25 02:30:05 1998
From: tomg at vivid.net (tomg)
Date: Fri, 24 Jul 1998 19:30:05 -0500
Subject: Electro Harmonix EFM Page
Message-ID: <yam7509.259.120863616@mail.vivid.net>

Added a EH page with the ele mistress stuff on it. Scans need to be bigger but
I'm low on space. Maybe I need to put 'em on DIY..

http://www.tomg.vivid.net/misc/eh.html

-Tom




From tomg at vivid.net  Sat Jul 25 02:32:12 1998
From: tomg at vivid.net (tomg)
Date: Fri, 24 Jul 1998 19:32:12 -0500
Subject: Maxx VCO-4A
Message-ID: <yam7509.606.120863616@mail.vivid.net>

Final of the VCO-4A w/layout. What a great VCO!


http://www.tomg.vivid.net/maxx/page_031.html


-Tom




From pfperry at melbpc.org.au  Sat Jul 25 03:05:03 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sat, 25 Jul 1998 11:05:03 +1000 (EST)
Subject: Theremin
Message-ID: <1.5.4.16.19961216174030.2b1fb526@popa.melbpc.org.au>

this is part of a post from Miha Tomsic <miha.tomsic at guest.arnes.si>
who used to be on this list... it seems so promising for a 'cheap &
completely different' alternate controller that I asked could i post it here..
and here it is (those ultrasonic things are very cheap BTW)

>When I was working on my diploma (Diffraction of ultrasound on zone plate)
>i ran into an interesting phenomenon. 
>I am using the setup with cheap piezo ultrasound transducer (@40kHz) and
>receiver. The ultrasound is very well reflected from all hard flat
>objects and it interferes coherently. So when I am moving objects around
>the transducer/receiver pair I get amplitude modulation of the 40kHz
>carrier in the range of sonic and subsonic frequencies. The object can be
>the palm of my hand, my body, notebooks... anything really. Quicker
>motions give me higher modulation frequancy and the distance from the t/r
>pair give me shallower or higher modulation. 
>I only need to follow the envelope and I get a nice "bass machine". I am
>wandering how it would sound like. 
> - Miha Tomsic --- C. na postajo 55 -- SI-1351 Brezovica pri Lj. --- SLOVENIA -
> - home-made -- electronics -- music -- industrial -- physics -- net -- linux -
> - phylosophy -- poetry -- arts ---- Lower Parts of Abdomen ---- Josef Banale -
>
relayed by paul perry melbourne australia




From costello at seanet.com  Sat Jul 25 05:38:39 1998
From: costello at seanet.com (Sean Costello)
Date: Fri, 24 Jul 1998 20:38:39 -0700
Subject: More Nonlinear
References: <01BDB61F.03EAC1C0.ebarbour@svetlana.com> <199807242325.BAA20173@piraya.electrum.kth.se> <35c41ba7.169769781@mail.lan>
Message-ID: <35B9533F.3FF6B8F1@seanet.com>

Scott Gravenhorst wrote:
> 
> Ok, this weekend is "nonlinear feedback filter mad scientist" weekend.
> I've decided on a state variable filter because it can be converted
> easily to a simple single pole LP filter with an SPST switch.  It also
> has two feedback paths to mess up with nonlinearities.  I've come up
> with 5 or 6 simple nonlinear devices that I can patch in to test.  I
> will be using an LM13600 for the OTAs.  For now, I will control the
> nonlinear stuff with a simple pan pot to pan between a linear path and
> a nonlinear one or maybe two different nonlinear paths, but if it
> sounds wierd/good, I will eventually devise some kind of VC panning
> system.

Cool!! Keep us posted!  My one request: try a full-wave rectifier in one
of the feedback loops.

Question:  Doesn't increasing feedback in a state-variable filter
actually increase the damping (i.e. less Q)?  If so, the effects of
nonlinear feedback in a state variable filter might be very different
than nonlinear feedback in a Moog-style filter, or a Sallen-Key filter.
Man, I need to get that Electronotes 4-pole filter running again, so I
can put circuits in the feedback loop.

Sean Costello



From erik.hecht at mbv.tu-chemnitz.de  Sat Jul 25 13:18:08 1998
From: erik.hecht at mbv.tu-chemnitz.de (Erik Hecht)
Date: Sat, 25 Jul 1998 13:18:08 +0200
Subject: Analog-effects
Message-ID: <35B9BEEF.22938912@mbv.tu-chemnitz.de>

Hi there!

Does anyone have some simple schematics of simple analog effects?
If there are links on the net where I can find it mail them to me.

Thanx

Erik




From chordman at flash.net  Sat Jul 25 18:56:32 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sat, 25 Jul 1998 16:56:32 GMT
Subject: GIF of nonlinearity circuits I thought of
Message-ID: <35be0d17.8901638@mail.lan>

Here is a URL for a 3.5k GIF of the nonlinear circuits I want to try
in a state variable filter feedback loop.

http://www.teklab.com/~chordman/nonlinearities.gif

I will also do full wave rectification, probably using a transistor
with equal size collector and emitter resistors 2 caps and 2 diodes.

Comments are welcome.


Oh, and I'm not really sure how item D will work, or if it's even
nonlinear.


-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From smart at nn.com  Sat Jul 25 20:14:44 1998
From: smart at nn.com (Mark Smart)
Date: Sat, 25 Jul 1998 13:14:44 -0500 (CDT)
Subject: Fluid-based delay?
In-Reply-To: <0ce193755171978MAIL01@toast.net> from "Dennis Dorgan" at Jul 25, 98 12:57:13 pm
Message-ID: <199807251814.NAA30905@medusa.nn.com>

In a somewhat related vein, there is the Cooper Time Cube. I used to work
at the University of Illinois Experimental Music Studios where they had one
of these. It's a box with two clear plastic tubes and some transducers in
it. At each end of each tube is a transducer. An incoming audio signal is
converted to sound by the transducer at one end. The sound travels through
the tube (which is coiled up for more length, I think) and comes out the
other end, where it is converted back to an electrical signal by the other
transducer. One tube has a delay of 14 ms, and the other is 16 ms. By
cascading the two tubes together, you can get a total of 30 ms!
The delay times are not adjustable, but you can create repeating effects by
feeding some output back to the input. I never actually heard this thing
get used, but from the manual I looked at, it had pretty good frequency
response characteristics. This was invented by some professor at U of I in
the late '60's, I believe.

How long did the tubes have to be? Well, sound travels at 1100 feet/second
so 1100(0.014)=15.4 feet.


************************************************
*     Mark Smart                               *
*     Electronics Engineer                     *
*     NovaNET Learning, Inc.                   *
*     smart at medusa.nn.com                      *
************************************************



From chordman at flash.net  Sun Jul 26 00:16:01 1998
From: chordman at flash.net (Scott Gravenhorst)
Date: Sat, 25 Jul 1998 22:16:01 GMT
Subject: Threatening and Abusive Emails
Message-ID: <35be58e8.17669399@mail.lan>

Is anyone else on the list getting threatening or abusive emails from
tuan_td at yahoo.com ?



-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman



From JWBarlow at aol.com  Sun Jul 26 02:37:12 1998
From: JWBarlow at aol.com (JWBarlow at aol.com)
Date: Sat, 25 Jul 1998 20:37:12 EDT
Subject: Fluid-based delay?
Message-ID: <eaded3d.35ba7a3a@aol.com>


In a message dated 7/25/98 10:19:27 AM, you wrote:

>How long did the tubes have to be? Well, sound travels at 1100 feet/second
>so 1100(0.014)=15.4 feet.

I thought the speed of sound is based on the density and temperature of the
medium through which it is traveling.

JB



From Dragonser at aol.com  Sun Jul 26 09:02:02 1998
From: Dragonser at aol.com (Dragonser at aol.com)
Date: Sun, 26 Jul 1998 03:02:02 EDT
Subject: question about Ua726 and Japanese Urban music web site
Message-ID: <7ae55d21.35bad46b@aol.com>

Hope someone on this list can read Japanese !
just Did a search on UA 726 , the hard to get IC , and came across a site For
Urban music in Tokyo .
 However the site was in Japanese , and 1., I haven't got the software to
display this correctly . And 2. I can't read Japanese anyway .....
Would anyone be able to help with a rough translation ? 
web address was http://www.urbanmusic.com/repair.html.
many thanks for you help 
Peter 
South London England 



From cmacdon at ix.netcom.com  Sun Jul 26 09:21:39 1998
From: cmacdon at ix.netcom.com (cmacdon at ix.netcom.com)
Date: Sun, 26 Jul 1998 00:21:39 -0700
Subject: PWM schematic
Message-ID: <35BAD903.268C@ix.netcom.com>

Hi,

If anyone is interested, I have put a schematic for a pulse
converter/PWM circuit at http://www.evenfall.com/diy/pwm.html

It's pretty simple, using a 4093 NAND and an omp amp.  I just finished
breadboarding it and it seems to work okay (on a scope and audibly). 
It's possible to make four of them out of just the two chips, which I
plan to do since none of my oscillators have a pulse out!

I tried the PWM circuit posted on music machines:

http://www.hyperreal.org/music/machines/categories/do-it-yourself/schematics/pulsewdith.circuit 

and it worked okay but I wasn't able to get really narrow pulses out of
it, so I looked inside a Serge comparator for some inspiration and came
up with the schematic above.  :)

-Chris MacDonald



From fa_diy at fa.camelot.de  Sun Jul 26 13:36:00 1998
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 26 Jul 1998 13:36:00 +0200
Subject: original and ingenious circuits ...
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D58287E7E1@nbgm336a.nbgm.siemens.de>
Message-ID: <6ycAhH9pHFB@fa.camelot.de>

Hello Juergen

>So, what little circuit details made the greatest impression on all
>of you ?
First of all there is the cymbal of the TR-808. But I was astonished also  
about this very simple one-transistor-VCA in the Roland JX3P.


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 eduni at ucsd.edu  Sun Jul 26 20:50:39 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Sun, 26 Jul 1998 11:50:39 -0700 (PDT)
Subject: More Nonlinear
Message-ID: <199807261850.LAA24628@smtp.ucsd.edu>

>Perhaps something like a starved tube in the feedback path where
>the starvation is voltage controlled.  Or perhaps a filter with
>switchable nonlinearity elements in the feedback path, these 
>elements may perhaps also be controlled by an external voltage.
>Or would something like this just oscillate wildly or go 
>randomly chaotic too easily?

-depends of course on where exactly you put what.  however, offhand, i'd
expect a system like that to oscillate.  not that that's bad, by any means.

Ethan




From eduni at ucsd.edu  Sun Jul 26 20:57:38 1998
From: eduni at ucsd.edu (Ethan Duni)
Date: Sun, 26 Jul 1998 11:57:38 -0700 (PDT)
Subject: Fluid-based delay?
Message-ID: <199807261857.LAA24680@smtp.ucsd.edu>

-another similar interesting system i was told of was one where the tubes in
question were filled with materials that conduct sound _more_ quickly than
air, so you actually get a negative delay (though not a whole lot).  never
heard whether it got built, though.  i think the idea was to use helium..
could be wrong.. 

Ethan




From aschrock at cs.brandeis.edu  Sun Jul 26 22:27:06 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Sun, 26 Jul 1998 16:27:06 -0400 (EDT)
Subject: Fluid-based delay?
In-Reply-To: <199807251814.NAA30905@medusa.nn.com>
Message-ID: <Pine.HPP.3.95.980725150848.27242A-100000@bay.cs.brandeis.edu>

This all reminds me somewhat of what the duo "windy and carl" do. They're
an ambient duo, except they use all acoustic instruments (for the most
part). For 1 album I believe they used a 45 second underground reverb
water tank. Very cool. Some of these somewhat older (and now progressively
more low-tech) solutions work pretty well.. a "real" reverb back from when
they used reverb _rooms_ has a very nice feel... I was tempted last year
to turn an unoccupied room in my dorms basement into a reverb room, but
opted not to due to since it would have been a bit of a pain. (not to
mention asking for trouble since I do most of my mixing at 2am..) 

All of these solutions require a minimum of parts.. a mic or two, a decent
pair of speakers. Of course, as people will probably be eager to tell you,
unless you're just looking for an "effect", you'll want to be really
careful with placement, mic type etc. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From kav200 at omicron.ACF.NYU.EDU  Sun Jul 26 22:56:33 1998
From: kav200 at omicron.ACF.NYU.EDU (Kristjan Varnik)
Date: Sun, 26 Jul 1998 16:56:33 -0400 (EDT)
Subject: psu question
Message-ID: <Pine.OSF.3.95.980726164544.22079A-100000@omicron.acf.nyu.edu>

Hi,

I read in a magazine about a simple 10 step sequencer
based around the 4017 decade counter, and I have
a fatman running on a 12v wall wart that is 1000mA.
The fatman needs at least 400 mA.

I was wondering if I could run some wires into that wall-wart to
run other 12v modules at the same time off that power supply? 

secondly is the 4017 a good chip to build a sequencer around,
or is there something that is alittle better, but not much more
difficult. The archives mentioned 40193, but that seemed to be
over my head.

Any suggestions or books/sites that can help would be appreciated.


Thanks,
Kristjan







From oakley at enterprise.net  Sun Jul 26 23:45:24 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Sun, 26 Jul 1998 22:45:24 +0100
Subject: Finished at last....
Message-ID: <000a01bdb8df$d2669d40$94c548c2@default>

Well, I have finally come to the end. My analogue monosynth is now finished.
Because it is switch linked and is not modular, I can no longer add anymore
stuff to it. I realised that this must be the end when I had to resort to
heat glue to fix my last addition inside it. There was no more space for new
boards to be placed. The front panel is stuffed to capacity with switches
and pots. I remember I once thought that modular synths were too big and too
unweildy to be usable, all that patch cording... so I built a switched
linked one... but now I hanker for a new design, one that I can add to when
time and funds allow. So my next project(and next) will be a modular this,
that and the other. And I have this list to thank for this new found
obsession.

All the best,

Tony Allgood.




From oakley at enterprise.net  Sun Jul 26 23:52:01 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Sun, 26 Jul 1998 22:52:01 +0100
Subject: Rectifiers
Message-ID: <000b01bdb8df$d36a0380$94c548c2@default>

A little while ago I wrote about active rectifiers. Use the one in Horowitz
and Hill with a TL072 and BAT-42s and it works a treat. Fast and very little
breakthrough of the fundamental. With 1N4148s, the breakthrough is audible.
If you use a small trimmer (2k2) to divert the signal into either the summer
OR the rectifier op-amp the breakthrough can be minimised still further by
making the gain through each path identical. I used 100k resistors
throughout. Two in parallel for r/2.

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

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

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






From synth1 at airmail.net  Sun Jul 26 23:58:16 1998
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 26 Jul 1998 21:58:16 -0000
Subject: DIY grab box bid info
Message-ID: <01BDB8E0.D8AC5680@dal16-15.ppp.iadfw.net>

Current high bid is $60.

There is a 100% functional Roland (d*****l) LAPC-1 sound
card in there as well.

Bids extended to noon tomorrow.

Paul Schreiber




From steve at babcom.u-net.com  Mon Jul 27 01:10:53 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Mon, 27 Jul 1998 00:10:53 +0100
Subject: Minimoog VCF Problems.
Message-ID: <35BBB77E.3B2BB47B@babcom.u-net.com>

Hi,

I've recently tried building the Minimoog VCF from the schematic which is
widely available online, from Music Machines and elsewhere. The file is called "minifilt.gif".

Has anyone else actually built this, as I cannot get the output diff amp to
work, and have had to resort to an opamp based solution.

Is there a fault in the schematic?

Also, has anyone any thoughts on the sound quality of different ladder
filters, i.e. is there actually an advantage to using a "modern" approach with
ic transistor arrays, fet opamps, etc.?

Sorry if this topic has been covered before.

Thanks,

Steve.





From pfperry at melbpc.org.au  Mon Jul 27 01:47:33 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 27 Jul 1998 09:47:33 +1000 (EST)
Subject: Fluid-based delay?
Message-ID: <1.5.4.16.19961218162257.388f61f0@popa.melbpc.org.au>

At 11:57 AM 26/07/98 -0700, Ethan Duni wrote:
>-another similar interesting system i was told of was one where the tubes in
>question were filled with materials that conduct sound _more_ quickly than
>air, so you actually get a negative delay (though not a whole lot).  never
>heard whether it got built, though.  i think the idea was to use helium..
>could be wrong..
.....negative delay?
sounds like the legendary Precognita 100....

paul perry melbourne australlia 




From WeAreAs1 at aol.com  Mon Jul 27 02:57:53 1998
From: WeAreAs1 at aol.com (WeAreAs1 at aol.com)
Date: Sun, 26 Jul 1998 20:57:53 EDT
Subject: Fluid-based delay?
Message-ID: <7d81946d.35bbd092@aol.com>


In a message dated 7/26/98 11:00:58 AM, you wrote:

<< -another similar interesting system i was told of was one where the tubes
in
question were filled with materials that conduct sound _more_ quickly than
air, so you actually get a negative delay (though not a whole lot).  never
heard whether it got built, though.  i think the idea was to use helium..
could be wrong.. 

Ethan  >>

No, helium is what you inhale to get that pitch-shifting effect.  Doesn't last
long, though.  If you want the precognitive delay effect, try inhaling nitrous
oxide.  Unfortunately, its effects, however thrilling, are also rather short-
lived.



From cmacdon at ix.netcom.com  Mon Jul 27 08:59:56 1998
From: cmacdon at ix.netcom.com (cmacdon at ix.netcom.com)
Date: Sun, 26 Jul 1998 23:59:56 -0700
Subject: Revision to PWM schematic
Message-ID: <35BC256C.36A7@ix.netcom.com>

My apologies, the schematic I mentioned for the PWM circuit had an error
in it.  The input to the NAND gate at pin 2 should go to V+, not
ground.   I have fixed it on the diagram at
http://www.evenfall.com/diy/pwm.html 
Sorry!

-Chris



From pfperry at melbpc.org.au  Mon Jul 27 10:42:51 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 27 Jul 1998 18:42:51 +1000 (EST)
Subject: HT-8955 audio delay chip
Message-ID: <1.5.4.16.19961219011820.12972f3e@popa.melbpc.org.au>

The UK magazine ETI (also sold in USA) has a Penfold stripboard
delay unit using this.. the chip is a 10bit A/D and D/A convertor
designed to interface with standard memory (in this case a 41256
DRAM). Would be very easy to hack this unit to have a cv controlled
delay unit up to 800ms.
BUT, who makes the chip? Anyone?

paul perry perplexed in melbourne australia
...ETI vol27 #6 22May-19June 1998 p19-24




From Colin.Fraser at scottishpower.plc.uk  Mon Jul 27 11:35:59 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Mon, 27 Jul 1998 10:35:59 +0100
Subject: HT-8955 audio delay chip
Message-ID: <01F675ABB3FFD111A6AA0008C728D5A50364A5@CATSPRNTS10>

They are made by Holtek.

See http://www.holtek.com.tw/Products/consumer/consumer.htm


Colin f


-----Original Message-----
From: Paul Perry [mailto:pfperry at melbpc.org.au]
Sent: 27 July 1998 09:43
To: synth-diy at mailhost.bpa.nl
Subject: HT-8955 audio delay chip


The UK magazine ETI (also sold in USA) has a Penfold stripboard
delay unit using this.. the chip is a 10bit A/D and D/A convertor
designed to interface with standard memory (in this case a 41256
DRAM). Would be very easy to hack this unit to have a cv controlled
delay unit up to 800ms.
BUT, who makes the chip? Anyone?

paul perry perplexed in melbourne australia
...ETI vol27 #6 22May-19June 1998 p19-24



From Giles.WARD at sema.co.uk  Mon Jul 27 14:43:07 1998
From: Giles.WARD at sema.co.uk (WARD Giles)
Date: Mon, 27 Jul 1998 13:43:07 +0100
Subject: Software Synthesis
Message-ID: <199807271246.NAA14470@gateway1.sema.co.uk>

Hi folks,

I've just joined this list and it's all about electronics -
unsurprisingly!  Am I on the right list to find out about software
synthesis, DSP etc. ?  Does this ever get discussed here?  If I'm
barking up the wrong end of a talkbox tube let me know!

Cheerio

Giles



From thudson at cygnus.com  Mon Jul 27 17:17:35 1998
From: thudson at cygnus.com (Thomas Hudson)
Date: Mon, 27 Jul 1998 11:17:35 -0400
Subject: Software Synthesis
References: <199807271246.NAA14470@gateway1.sema.co.uk>
Message-ID: <35BC9A0F.8602BFBF@cygnus.com>

The music-dsp mailing list is devoted to these subjects:
http://shoko.calarts.edu/~glmrboy/musicdsp/music-dsp.html

Thomas


WARD Giles wrote:
> 
> Hi folks,
> 
> I've just joined this list and it's all about electronics -
> unsurprisingly!  Am I on the right list to find out about software
> synthesis, DSP etc. ?  Does this ever get discussed here?  If I'm
> barking up the wrong end of a talkbox tube let me know!
> 
> Cheerio
> 
> Giles



From WeAreAs1 at aol.com  Mon Jul 27 17:33:01 1998
From: WeAreAs1 at aol.com (WeAreAs1 at aol.com)
Date: Mon, 27 Jul 1998 11:33:01 EDT
Subject: HT-8955 audio delay chip
Message-ID: <2bd52172.35bc9df2@aol.com>


In a message dated 7/27/98 12:47:58 AM, you wrote:

<<The UK magazine ETI (also sold in USA) has a Penfold stripboard
delay unit using this.. the chip is a 10bit A/D and D/A convertor
designed to interface with standard memory (in this case a 41256
DRAM). Would be very easy to hack this unit to have a cv controlled
delay unit up to 800ms.
BUT, who makes the chip? Anyone?

paul perry perplexed in melbourne australia
...ETI vol27 #6 22May-19June 1998 p19-24>>

Paul,

That chip is made by Holtek.  You can get info and PDF data sheets from their
website (http://www.holtek.com, I think...)  They have a couple of other kind
of interesting audio IC's.

I wonder if the chip can be tricked into addressing more than one 41256 RAM?
It would be nice to be able to get more than 800ms at full bandwidth.  Any
ideas?  Also, I couldn't quite figure out where to inject the clock in the ETI
circuit (for voltage control).  Can you see it?  (I don't have the magazine -
I just saw on a newstand a few days ago)

Best regards,
Michael Bacich



From fa_diy at fa.camelot.de  Mon Jul 27 21:22:00 1998
From: fa_diy at fa.camelot.de (Florian Anwander)
Date: 27 Jul 1998 21:22:00 +0200
Subject: Fluid-based delay?
In-Reply-To: <199807261857.LAA24680@smtp.ucsd.edu>
Message-ID: <6ygBPQXKHFB@fa.camelot.de>

Hallo Ethan

> i think the idea was to use helium.. could be wrong..
If you have a swimming pool in your garden it should be a nice experiment (if  
fails, dont worry, go swimming...)


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 Chris.List at sc.siemens.com  Mon Jul 27 22:45:04 1998
From: Chris.List at sc.siemens.com (List, Christopher)
Date: Mon, 27 Jul 1998 16:45:04 -0400
Subject: WWW, Quantizer, & LM1036 Notes
Message-ID: <81A062BC5305D111A9D700805F065968CE948B@maildepo.sc.siemens.com>

Hi all - 

Thanks for the feedback so far on my www pages. Just a quick note - 

Several of you asked for a schem of the CV qunatizer we discussed last
week. It is now on my page under "resources" (along with just about
everything else). It's just a schem without much explanation at this
point - but there's enough to figure it out I think. More to come soon!

I've also posted (by popular demand) the builder's notes I used to
include with the ASM-1 faceplates that I sold.

Lastly, there was a slight error between the faceplate and the LM1036
schems and v-board layout due to the left / right channels. The schems
have been corrected. Pictures of my completed module coming soon...

- CList
http://www.mindspring.com/~clist



From tsheets at saturn5.com  Mon Jul 27 23:54:45 1998
From: tsheets at saturn5.com (Troy Sheets)
Date: Mon, 27 Jul 1998 14:54:45 -0700 (PDT)
Subject: new oscillator chips?
Message-ID: <199807272154.OAA03796@atari.saturn5.com>


I am wondering if there are any oscillator chips out there besides CEM
that are suitable for audio use?  I am looking for something cheap and
easily available.

CEM VCOs are limited in supply, correct?

-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 yoh212 at lulu.acns.nwu.edu  Tue Jul 28 00:03:03 1998
From: yoh212 at lulu.acns.nwu.edu (Yoshiki Ohmura (Yoshi))
Date: Mon, 27 Jul 1998 17:03:03 -0500 (CDT)
Subject: SH-101 Mods
Message-ID: <Pine.HPP.3.93.980727165958.11229A-100000@lulu.acns.nwu.edu>


Does anybody have the schems/instructions on how to convert the 101 in to
a "modular" 101?  I know Analogue solutions does one, but I want to do
mine myself ;)  Any help would be much apreciated.  If it doesn't exist as
a whole, I would apreciate it if people who did individual mods, such as
LFO, or VCO out, or VCF in, could let me in on the secret.  Like that I
could piece together the whole thing.

Thanks for the help.

Cheers

Yoshi





From jmaxwell at POMONA.EDU  Tue Jul 28 00:28:59 1998
From: jmaxwell at POMONA.EDU (Stupid Octave Cat)
Date: Mon, 27 Jul 1998 15:28:59 -0700 (PDT)
Subject: SH-101 Mods
In-Reply-To: <Pine.HPP.3.93.980727165958.11229A-100000@lulu.acns.nwu.edu>
Message-ID: <Pine.PMDF.3.95.980727150602.539038576E-100000@POMONA.EDU>

On Mon, 27 Jul 1998, Yoshiki Ohmura (Yoshi) wrote:

> 
> Does anybody have the schems/instructions on how to convert the 101 in to
> a "modular" 101?  I know Analogue solutions does one, but I want to do
> mine myself ;)  Any help would be much apreciated.  If it doesn't exist as
> a whole, I would apreciate it if people who did individual mods, such as
> LFO, or VCO out, or VCF in, could let me in on the secret.  Like that I
> could piece together the whole thing.

It's interesting that you posted this, because I have been wondering the
same since I started novamodding mine again (there's just no space for
everything I want to do).  I have decided that I really want to rackmount
the unit, basically breaking out every patch point, input, etc that I can
think of.  If you're interested, I'd love to get this project going.  I've
learned a lot from the Nova Mod stuff, and it seems that patching it out
would only make it better.

Justin


   justin.kendrick.maxwell   %(stupid/octave\cat)%     &web.&musik.&info
---------------------- http://pages.pomona.edu/~jmaxwell ------------------
work>> jmaxwell at sonypictures.com      -+-    jmaxwell at pomona.edu <<personal




From sasami at blaze.net.au  Tue Jul 28 01:13:47 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Tue, 28 Jul 1998 09:13:47 +1000 (EST)
Subject: Tube Bandpass
Message-ID: <199807272313.JAA04008@blaze.net.au>


Stage 1 of my tube bandpass VCF has been completed. Eric's design of course. 

A photo of the module as it stands (basic chassis) is at
http://www.blaze.net.au/~sasami/synth/bandpass.jpg

Input and output jacks have been removed for the photo, as they were only
tacked on. Building it was relatively straight forward, and a pleasant
change from printed circuits. A six way tag strip salvaged from my SH-5
coupled with the tube socket and pot tags provided sufficient mounting points.

Still to go are the voltage control stuff and the panel and case. Components
generally are a mix of old and new. The 5 pin din is for power - nothing
else I have uses this sort of plug :)

I've tried it out on square waves, both, static and swept. Hardly NATA
testing, but that was what was to hand. 

Personal feelings-

The effect of the filter is a little weak with the Q down, but bringing it
up makes it quite satisfactory. Eric does mention this in his notes,
suggesting  two stages may be required for those that require a stronger effect.

My only comment so far is to make sure you put a bleed capacitor across the
150V filter capacitors of the power supply. This resistor will gradually
drain the capacitor when you power down. A neon lamp wouldn't hurt either,
as it will give you some idea of how much charge is left.  Not only will
this reduce the chance of you zapping yourself, but more importantly, it
stops you really making a mess of your tools when you accidently short out
the rails :)

Thanks Eric.

Cheers

Ken
_______________________________________________________________________
Ken Stone   sasami at blaze.net.au  
Catgirl Paradise <http://www.anime.net/~kens/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




From aschrock at cs.brandeis.edu  Tue Jul 28 02:09:32 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Mon, 27 Jul 1998 20:09:32 -0400 (EDT)
Subject: SH-101 Mods
In-Reply-To: <Pine.HPP.3.93.980727165958.11229A-100000@lulu.acns.nwu.edu>
Message-ID: <Pine.HPP.3.95.980727200552.1221B-100000@bay.cs.brandeis.edu>

On Mon, 27 Jul 1998, Yoshiki Ohmura (Yoshi) wrote:
> Does anybody have the schems/instructions on how to convert the 101 in to
> a "modular" 101?  I know Analogue solutions does one, but I want to do
> mine myself ;)  Any help would be much apreciated.  If it doesn't exist as
> a whole, I would apreciate it if people who did individual mods, such as
> LFO, or VCO out, or VCF in, could let me in on the secret.  Like that I
> could piece together the whole thing.

Uhm... it's pretty cake if you have schematics. Just make any connection
that you want to make "modular" normaled.. so that w/out a jack inserted
it operates normally, but when you insert a jack the signal is diverted. 

I like having mine semi-modular. Some things are handy to have access to
remotely, like random and VCF in, but some things you might just not care
about. 

You can put lots of 1/4" jacks along the back where the battery holder
is... space for maybe 10? of course the problem with this is that you
can't use batteries with it. Ahh well, you gain a lot of functionality. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|






From ebarbour at svetlana.com  Tue Jul 28 02:50:27 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Mon, 27 Jul 1998 17:50:27 -0700
Subject: tube VCF
Message-ID: <01BDB987.0A6A3CE0.ebarbour@svetlana.com>


>>Stage 1 of my tube bandpass VCF has been completed.
>>Eric's design of course. 
>>My only comment so far is to make sure you put
>>a bleed capacitor across the
>>150V filter capacitors of the power supply.
Bloody right. A 47k 2-watt resistor is suitable--the voltage will
be at safe levels within 1 minute of power-off.

>>Thanks Eric.
My pleasure. Please tell others that it 
A) actually sound good
B) won't kill them and
C) isn't swamped with distortion and noise. :)

And if anyone needs a power-supply design, contact me.

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA






From pfperry at melbpc.org.au  Tue Jul 28 11:02:04 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Tue, 28 Jul 1998 19:02:04 +1000 (EST)
Subject: HT-8955 audio delay chip
Message-ID: <1.5.4.16.19961220013728.3997ee80@popa.melbpc.org.au>

At 11:33 AM 27/07/98 EDT, Michael Bacich WeAreAs1 wrote:
>

>ideas?  Also, I couldn't quite figure out where to inject the clock in the ETI
>circuit (for voltage control).  Can you see it?  

there is a resistor connected between pins 8 and 9, varying between 570K and
100k.
I imagine you could replace this by one of those 'linear' optocouplers, or
rig up
something with a vactrol..
all I need now is somewhere that sells them in small quantities...
DigiKey dont have them acc to their online cat :(

paul perry melbourne australia not florida




From tomg at vivid.net  Tue Jul 28 12:32:51 1998
From: tomg at vivid.net (tomg)
Date: Tue, 28 Jul 1998 05:32:51 -0500
Subject: Maxx VCF-5A MS5O clone
Message-ID: <yam7513.2586.120547704@mail.vivid.net>

The VCF-5A is based on the MS5O. This is worlds most dangerous VCF only ear
plugs can save you with the resonance up over half way, it's like sticking a
ice pick in your brain. This one is best build in the daytime so you don't
wake up the block twisting the res pot. Used a 3O45/46 in place of the diode
block, works very well.


http://www.tomg.vivid.net/maxx/page_032.html

-Tom






From graham at dashdash.demon.co.uk  Tue Jul 28 14:40:16 1998
From: graham at dashdash.demon.co.uk (Graham Wignall)
Date: Tue, 28 Jul 1998 13:40:16 +0100
Subject: Ring Modulators
Message-ID: <35BDC6B0.F1E13230@dashdash.demon.co.uk>

Does anyone have any real, live, workable schematics/designs for a ring
modulator? I'm just planning a major add-on set for a FatMan, and I want
to put a ring mod or two in there.

So far all I've found is one from a 1973 home-brew synth, which uses a
chip (SG3402) I can't trace anymore.

Graham Wignall



From Juergen.Haible at nbgm.siemens.de  Tue Jul 28 17:19:24 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 28 Jul 1998 17:19:24 +0200
Subject: AW: Maxx VCF-5A MS5O clone
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5828D4100@nbgm336a.nbgm.siemens.de>

	>The VCF-5A is based on the MS5O. This is worlds most dangerous VCF
only ear
	>plugs can save you with the resonance up over half way, it's like
sticking a
	>ice pick in your brain. This one is best build in the daytime so
you don't
	>wake up the block twisting the res pot. Used a 3O45/46 in place of
the diode
	>block, works very well.
	>
	>
> http://www.tomg.vivid.net/maxx/page_032.html
	>

Hi Tom,

How have you matched the discrete diodes to the transistor array ?

Where's the original temp compensation circuit ?

JH.






From Juergen.Haible at nbgm.siemens.de  Tue Jul 28 17:23:13 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Tue, 28 Jul 1998 17:23:13 +0200
Subject: AW: SH-1000 LFO
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5828D410F@nbgm336a.nbgm.siemens.de>

	>Well, thank you everybody for all your help in finding out what my
	>mystery component is! Everybody was saying either UJT (which seemed
to
	>match better, functionwise) or SCR (which matches the symbol
	>description). None of them looked right, though, and I still
couldn't
	>find any similar circuits to mine that I could peruse for hints on
	>what was wrong.

Most VCOs in Korg synths that I have seen use SCRs to discharge
the capacitor. Only that these SCRs don't look like SCRs, because
they are built from discrete npn and pnp transistors.

JH.
>  



From ebarbour at svetlana.com  Tue Jul 28 18:40:21 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Tue, 28 Jul 1998 09:40:21 -0700
Subject: MIDI to anything
Message-ID: <01BDBA0B.BDE8D040.ebarbour@svetlana.com>


>Eric, this is a really cool idea and a great looking product.  One could
>use relays to control just about anything.  How about setting keys outside
>the normal playing range to control that Leslie speed?  Oh the ideas are
>endless.  Your idea for note on and off using relays and CV trim pots is
>outstanding.  Dual pole relays and trim pots could be used to to create a
>volt and hertz scale that could be tuned together so one set of relays
>could operate both scales in unison I guess.
>
>Thanks for passing along this info.  My electronic design skills are weak
>as I am a high voltage electrician.  But if I understand the interfacing
>correctly, the parallel output latches an external device as long as the
>voltage is between 7 and 35 volts.

???? huh? The 7-35v spec is for the POWER SUPPLY
of the MTP-1. It HAS to be in that range.
The parallel outputs are RELAY DRIVERS. Open collector.
That means that a key-down causes the corresponding 
relay output to be connected to ground.

>> So does the parallel output of the
>device act more like a switch in this process than a supply voltage?  Do
>you think each of the 32 outputs could operate with varied voltages?
>Thanks again,
>Larry Hendry

YOU DO NOT NEED RELAYS TO MAKE A VOLTAGE DIVIDER.
for this thing.
Just string an array of resistors or pots in series. Then connect
+v to one end, ground to the other. Then connect the MTP-1s
first relay output to the junction of the SECOND and THIRD
resistors. Connect your CV output to the junction of the FIRST
and SECOND resistors. 

When the first relay output goes to ground, the voltage divider formed
will give the MINIMUM voltage of the divider. The second relay
output will divide to the SECOND LOWEST CV. And so on.
The resistor values can be adjusted to give the CV scaling desired.

This will work even with two or more dividers. The only connection
of the MTP-1 to the dividers is a ground and a relay output that
grounds. So multiple dividers can be connected to the relay outputs
at once, they will work INDEPENDENTLY of each other (so long as only
one relay output is grounded).

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From aschrock at cs.brandeis.edu  Tue Jul 28 19:36:18 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Tue, 28 Jul 1998 13:36:18 -0400 (EDT)
Subject: another (US) Schaeffer-Apparatebau report
In-Reply-To: <yam7513.2586.120547704@mail.vivid.net>
Message-ID: <Pine.SGI.3.95.980728105110.10499A-100000@amber.cs.brandeis.edu>

I Just thought I would share my experience with Schaeffer-Apparatebau
KG... my panels arrived today. I had almost given up on them getting here
(it has been 3 weeks since they sent it; they said it would take a week,
and over 5 weeks since I made my order) and actually ordered an
alternative panel yesterday, since I only have until the end of August to
finish this project.. luckily it was cancellable. I guess the moral of the
story is to make sure you have adequate time to get essentials shipped
from another continent. They provice TOP RATE service, and this deal was
done 100% over email, saving me the cost of calling Germany. 

The total cost wasn't bad at all compared to the trouble I would go
through to actually get them engraved myself. The black background looks
great.. a very smooth matte finish. The lettering is quite sharp and VERY
readable, even from far away. (see JH's synthi clone for an example) The
engraving was extremely accurate.. all the mistakes on the panel were my
own fault. ("Sub" instead of "FM" in one spot is the main one.. doh) Mine
is 3mm thick aluminum... quite sturdy. It doesn't flex or bend at all with
jack insertion, and the aluminum seems to be harder/stiffer than other
cheaper panels I've worked with. I can't wait to get going and fill my
modular front panel up with pots and knobs. I'll put some pictures on my
web page after I drop a few modules in. (finished are the dual VCO and
dual VCA units, still to go: basically everything else: assembling my
motm-100, 3xADSR, 2xVCF, ringmod, c/v+audio mixer...) 

I also got a smaller panel made up for a prepatched mini-synth I'm putting
together. Both units use (ferociously expensive) small square e-switch
5500 series switches for various functions. I still have yet to design the
digital switching for this.. been putting it off. (see my previous lament
to the list) Why am I using expensive, square switches? Cuz, dammit, they
look and feel so nice. I guess I'm just unable to resist the temptation.
Look at the layout of the access virus to see what I mean. 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|




From johns at oei.com  Tue Jul 28 20:27:27 1998
From: johns at oei.com (John Speth)
Date: Tue, 28 Jul 1998 11:27:27 -0700
Subject: Cover vinyl source?
Message-ID: <000501bdba55$5fc25640$2c15d7d0@johns.oei.com>

I'm looking for this leather-look-alike vinyl (or vinyl like) stuff for
covering a case I'm building.  The ideal stuff would be like what's on my
Rhodes piano.  Many guitar amplifiers and speaker cabinets are covered in
this stuff.  It's tough, relatively thin, has no backing, and looks like
it'll glue to a wood substrate nicely using contact cement.  Does anybody
know where I can obtain some of this in the US?

Also I'm looking for a source of metal corner covers like the ones that
screw on guitar amps and speaker cabinets.  Anybody know of a US source for
these?

John Speth
Object Engineering, Inc
mailto:johns at oei.com





From mmcintos at ball.com  Tue Jul 28 21:33:45 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Tue, 28 Jul 1998 13:33:45 -0600
Subject: Sub-Miniature Tube Type List
Message-ID: <09DB74475204D1119C8200805F19D0032D12A0@aeromsg1.ball.com>

I came across this today and thought it may be a help to the folks
trying to build tube based modules (no, I haven't started my VCF yet!).

http://pw2.netcom.com/~wa2ise/radios/penciltubes.html

This page gives the tube number, type, pinout, heater V & A, plate
voltage and other good information for sub-miniature "pencil" tubes.

Malcolm



From jamos at technotoys.com  Tue Jul 28 22:20:25 1998
From: jamos at technotoys.com (Jim Johnson)
Date: Tue, 28 Jul 1998 13:20:25 -0700
Subject: another (US) Schaeffer-Apparatebau report
In-Reply-To: <Pine.SGI.3.95.980728105110.10499A-100000@amber.cs.brandeis.edu>
References: <Pine.SGI.3.95.980728105110.10499A-100000@amber.cs.brandeis.edu>
Message-ID: <199807281320250530.0124D1FD@mail.proaxis.com>

This is really cool. Thanks for sharing.

Could you post, or perhaps email me, the files you created with Front Panel
Designer? I've fiddled with it a bit, but not too seriously, because I
don't have time to dive into a project right now. I'd like to get a sense
of what's possible with it. (I'd like to do things like replace the fonts,
add graphics, radial lines for the knobs, etc., but I can't see how to do
these things in the version I've got.) 

TIA

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR ***********

On 7/28/98, at 2:27 PM, Andrew Schrock  wrote: 

>I Just thought I would share my experience with Schaeffer-Apparatebau
>KG... my panels arrived today. I had almost given up on them getting here
>(it has been 3 weeks since they sent it; they said it would take a week,
>and over 5 weeks since I made my order) and actually ordered an
>alternative panel yesterday, since I only have until the end of August to
>finish this project.. luckily it was cancellable. I guess the moral of the
>story is to make sure you have adequate time to get essentials shipped
>from another continent. They provice TOP RATE service, and this deal was
>done 100% over email, saving me the cost of calling Germany. 
>
>The total cost wasn't bad at all compared to the trouble I would go
>through to actually get them engraved myself. The black background looks
>great.. a very smooth matte finish. The lettering is quite sharp and VERY
>readable, even from far away. (see JH's synthi clone for an example) The
>engraving was extremely accurate.. all the mistakes on the panel were my
>own fault. ("Sub" instead of "FM" in one spot is the main one.. doh) Mine
>is 3mm thick aluminum... quite sturdy. It doesn't flex or bend at all with
>jack insertion, and the aluminum seems to be harder/stiffer than other
>cheaper panels I've worked with. I can't wait to get going and fill my
>modular front panel up with pots and knobs. I'll put some pictures on my
>web page after I drop a few modules in. (finished are the dual VCO and
>dual VCA units, still to go: basically everything else: assembling my
>motm-100, 3xADSR, 2xVCF, ringmod, c/v+audio mixer...) 
>
>I also got a smaller panel made up for a prepatched mini-synth I'm putting
>together. Both units use (ferociously expensive) small square e-switch
>5500 series switches for various functions. I still have yet to design the
>digital switching for this.. been putting it off. (see my previous lament
>to the list) Why am I using expensive, square switches? Cuz, dammit, they
>look and feel so nice. I guess I'm just unable to resist the temptation.
>Look at the layout of the access virus to see what I mean. 
>
>Andrew
>
>| Andrew Schrock							|
>| Network Programmer, Synthesizer and electronic music enthusiast	|
>| aschrock at cs.brandeis.edu						|



From tomg at vivid.net  Wed Jul 29 00:04:04 1998
From: tomg at vivid.net (tomg)
Date: Tue, 28 Jul 1998 17:04:04 -0500
Subject: Maxx VCF-5A MS5O clone
In-Reply-To: <yam7513.2586.120547704@mail.vivid.net>
Message-ID: <yam7513.200.120000160@mail.vivid.net>

On 28-Jul-98, tomg wrote:
>The VCF-5A is based on the MS5O. This is worlds most dangerous VCF only ear
>plugs can save you with the resonance up over half way, it's like sticking a
>ice pick in your brain. This one is best build in the daytime so you don't
>wake up the block twisting the res pot. Used a 3O45/46 in place of the diode
>block, works very well.


>http://www.tomg.vivid.net/maxx/page_032.html

>-Tom


I made some small changes to the schemo the pc layout was correct. Added
some text about why I did what I did. I don't have much time right now but
I'll be back.

BTW: as long as I'm fixing stuff. Fix and update on the 555/4OO7 adsr at
 
http://www.tomg.vivid.net/maxx/pics/adsr2_3.gif

-Tom




From costello at seanet.com  Wed Jul 29 00:21:34 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 28 Jul 1998 15:21:34 -0700
Subject: Matching Diodes, & filter FM
Message-ID: <35BE4EEE.68EEECD0@seanet.com>

Hi folks:

I am currently breadboarding a diode ladder filter. 

Two questions:

1) How should I go about matching the diodes in the circuit?  I have a
new multimeter, & a good breadboard w/a power supply (+12V, -12V, +5V),
so any simple circuits would be appreciated. 

2) I want to have filter FM as part of the circuit, where the input can
be used to FM the filter cutoff.  I was planning on using a single
op-amp as a buffer, and a second op-amp tapping into the output of the
first, acting as an amplifier for the signal before it goes into the
control node for the filter.  Am I missing anything here?

I have high hopes for this little box.  It will be based on a Practical
Electronics design, powered by 2 9V batteries, and should fit in a
Hammond 1590BB box when finished,.  It should have knobs for cutoff,
resonance, envelope sweep (knobs for Decay Rate and Amount - no attack
knob, as I want a simple decay-only circuit for maximum clarity), filter
FM, output level, possibly filter overdrive, and possibly a distortion
stage to go after the stage where the envelope signal is tapped off, but
before the filter.  Gotta find small knobs.  I have given up on the idea
on running this off of a single 9V battery for now, as it seems easier
to just put two batteries in the box.

Later,

Sean Costello



From costello at seanet.com  Wed Jul 29 00:23:20 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 28 Jul 1998 15:23:20 -0700
Subject: Maxx VCF-5A MS5O clone
References: <yam7513.200.120000160@mail.vivid.net>
Message-ID: <35BE4F58.E8230E05@seanet.com>

tomg wrote:
> 

> I made some small changes to the schemo the pc layout was correct. Added
> some text about why I did what I did. I don't have much time right now but
> I'll be back.

Looks cool.  One question:  why did you take the back-to-back diode
network out of the feedback loop in the op-amp that controls resonance?

Thanks,

Sean Costello



From sasami at blaze.net.au  Wed Jul 29 00:44:51 1998
From: sasami at blaze.net.au (Ken Stone)
Date: Wed, 29 Jul 1998 08:44:51 +1000 (EST)
Subject: tube VCF
Message-ID: <199807282244.IAA03783@blaze.net.au>

>
>>>Thanks Eric.
>My pleasure. Please tell others that it 
>A) actually sound good
>B) won't kill them and
>C) isn't swamped with distortion and noise. :)

Okay.

It actually sounds good :)  Yes, I mean that.

It hasn't killed me. Sure, you need to concentrate a little harder when the
voltages are higher, but it isn't anywhere near as dangerous as working with
mains, tv sets, monitors or computer switch mode power supplies.

As for noise and distortion, I didn't notice any.

This won't be my last tube project. 

Ken
_______________________________________________________________________
Ken Stone   sasami at blaze.net.au  
Catgirl Paradise <http://www.anime.net/~kens/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>




From tomg at vivid.net  Wed Jul 29 04:10:06 1998
From: tomg at vivid.net (tomg)
Date: Tue, 28 Jul 1998 21:10:06 -0500
Subject: AW: Maxx VCF-5A MS5O clone
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5828D4100@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7513.340.119368936@mail.vivid.net>

On 28-Jul-98, Haible Juergen wrote:
>>The VCF-5A is based on the MS5O. This is worlds most dangerous VCF
>only ear
>>plugs can save you with the resonance up over half way, it's like
>sticking a
>>ice pick in your brain. This one is best build in the daytime so
>you don't
>>wake up the block twisting the res pot. Used a 3O45/46 in place of
>the diode
>>block, works very well.
>>
>>
>> http://www.tomg.vivid.net/maxx/page_032.html
>>

>Hi Tom,

>How have you matched the discrete diodes to the transistor array ?

>Where's the original temp compensation circuit ?

>JH.


I made a few modifications to be basic circuit as I went. The most obvious
being the replacement of the diode block with a LM3O45/46 transistor array. My
fist thought was to use two arrays but I tested matched and unmatched diodes
and array transistors connecting the balanced ladder but anything out of the
box seemed to work just as well, with a little tweak to the balance trimmer,
so I settled on 1N914s. I also omitted the temp comp diodes. I tried it both
ways with a hair drier (not full on of course) and drift seemed about the
same. If they had performed some sort of compression or affected the sound I
would have left them in.

-Tom



 




From tomg at vivid.net  Wed Jul 29 04:10:53 1998
From: tomg at vivid.net (tomg)
Date: Tue, 28 Jul 1998 21:10:53 -0500
Subject: AW: Maxx VCF-5A MS5O clone
In-Reply-To: <1BF5E20E0C4DD111BBAB00805FE2D5828D4100@nbgm336a.nbgm.siemens.de>
Message-ID: <yam7513.2695.119368936@mail.vivid.net>

On 28-Jul-98, Haible Juergen wrote:
>>The VCF-5A is based on the MS5O. This is worlds most dangerous VCF
>only ear
>>plugs can save you with the resonance up over half way, it's like
>sticking a
>>ice pick in your brain. This one is best build in the daytime so
>you don't
>>wake up the block twisting the res pot. Used a 3O45/46 in place of
>the diode
>>block, works very well.
>>
>>
>> http://www.tomg.vivid.net/maxx/page_032.html
>>

>Hi Tom,

>How have you matched the discrete diodes to the transistor array ?

>Where's the original temp compensation circuit ?

>JH.


I made a few modifications to be basic circuit as I went. The most obvious
being the replacement of the diode block with a LM3O45/46 transistor array. My
fist thought was to use two arrays but I tested matched and unmatched diodes
and array transistors connecting the balanced ladder but anything out of the
box seemed to work just as well, with a little tweak to the balance trimmer,
so I settled on 1N914s. I also omitted the temp comp diodes. I tried it both
ways with a hair drier (not full on of course) and drift seemed about the
same. If they had performed some sort of compression or affected the sound I
would have left them in.

-Tom



 




From costello at seanet.com  Wed Jul 29 04:32:55 1998
From: costello at seanet.com (Sean Costello)
Date: Tue, 28 Jul 1998 19:32:55 -0700
Subject: Dan Slater's Article in CMJ, and X to the kth power - how do you do it?
Message-ID: <35BE89D7.B906928C@seanet.com>

Hi all:

The new Computer Music Journal (Volume 22, Number 2, Summer 1998)
finally hit the stands.  Dan Slater has a fascinating article in it -
"Chaotic Sound Systems."  Y'all gotta track it down.

Anyway, Mr. Slater describes a hypothetical Buchla module (complete with
an "artist's conception" that points out how truly beautiful the Buchla
200 designs were visually) that would implement a Ueda Attractor. As
described, the Ueda attractor circuit is very similar to a
state-variable filter, but with the inverting stage replaced with an x^3
stage (x cubed) and the signal input connected to the first integrator
stage.  Slater's hypothetical module uses an x to the k function, where
the circuit can be converted from a state variable topology to an Ueda
Attractor by changing the value of k (for a state-variable filter, k=1;
for the Ueda attractor, k=3).

How the heck would you do this?  Is there some common circuit that
produces an x to the k function, where k can smoothly vary (i.e. by
non-integer values) between 1 and 4?  x^1 is simple; x^2 could be a
multiplier where the input is multiplied by itself; x^3 could be created
by a second multiplier multiplying the input by the product of an x^2
stage.  But how do you get, say, x^2.74?  And how do you vary these
smoothly?  Could you use feedback from a multiplying stage, where a
signal is multiplied by the output of the multiplier?  Or maybe feedback
in a 2-multiplier configuration?

As always, any and all advice welcome.  I think that this would be a
cool circuit to own. 

Thanks,

Sean Costello



From dave at mail.kc.net  Wed Jul 29 05:15:33 1998
From: dave at mail.kc.net (Dave)
Date: Tue, 28 Jul 1998 22:15:33 -0500
Subject: Cover vinyl source?
In-Reply-To: <000501bdba55$5fc25640$2c15d7d0@johns.oei.com>
Message-ID: <3.0.1.32.19980728221533.00b4de34@mail.kc.net>

At 11:27 AM 7/28/98 -0700, John Speth wrote:
>I'm looking for this leather-look-alike vinyl (or vinyl like) stuff for
>covering a case I'm building.  
>Does anybody
>know where I can obtain some of this in the US?

I've often heard it referred to as 'Tolex,' but that's a brand name, like
Xerox or Band-Aid.
I know Peavey manufactures (or at least resells) that material, along with
all the corners and other various hardware you'll need.

Honestly, try a music store.  That's where I see it in the KC area.


Dave in KCMO USA
dave at o2.net
http://www.o2.net/~dave/




From jlarryh at iquest.net  Wed Jul 29 05:22:21 1998
From: jlarryh at iquest.net (J. Larry Hendry)
Date: Tue, 28 Jul 1998 22:22:21 -0500
Subject: MIDI to anything
Message-ID: <199807290319.FAA25355@mailhost.bpa.nl>

Thanks Eric.  I was totally confused here.  Your explanation below is
crystal clear.  Thanks for helping me out of the dark.
Larry



> ???? huh? The 7-35v spec is for the POWER SUPPLY
> of the MTP-1. It HAS to be in that range.
> The parallel outputs are RELAY DRIVERS. Open collector.
> That means that a key-down causes the corresponding 
> relay output to be connected to ground.
--------------> 
> YOU DO NOT NEED RELAYS TO MAKE A VOLTAGE DIVIDER.
> for this thing.
> Just string an array of resistors or pots in series. Then connect
> +v to one end, ground to the other. Then connect the MTP-1s
> first relay output to the junction of the SECOND and THIRD
> resistors. Connect your CV output to the junction of the FIRST
> and SECOND resistors. 
> 
> When the first relay output goes to ground, the voltage divider formed
> will give the MINIMUM voltage of the divider. The second relay
> output will divide to the SECOND LOWEST CV. And so on.
> The resistor values can be adjusted to give the CV scaling desired.
> 
> This will work even with two or more dividers. The only connection
> of the MTP-1 to the dividers is a ground and a relay output that
> grounds. So multiple dividers can be connected to the relay outputs
> at once, they will work INDEPENDENTLY of each other (so long as only
> one relay output is grounded).
> 
> Eric Barbour
> Svetlana Electron Devices
> Portola Valley CA USA
> 



From djbrow at pacifier.com  Wed Jul 29 05:59:43 1998
From: djbrow at pacifier.com (David Brown)
Date: Tue, 28 Jul 1998 20:59:43 -0700
Subject: Cover vinyl source?
Message-ID: <3.0.5.32.19980728205943.007c9280@mail.pacifier.com>

>At 11:27 AM 7/28/98 -0700, John Speth wrote:
>I'm looking for this leather-look-alike vinyl (or vinyl like) stuff for
>covering a case I'm building. Does anybody know where I can obtain some
>of this in the US?

I've recovered a lot of amps, Rhodes, etc.  I go to an auto
upholstery shop and buy tonneau cover material.  It looks
really close to Tolex, comes in all sorts of colors (I've
only used brown and black) and is 72" wide.  It's great for
big amps.  The cost is pretty low (although it's been a while
so I don't remember exactly ... probably $10 to $15 a yard).

Dave
-------------------
    David Brown
djbrow at pacifier.com



From dslater at ix.netcom.com  Wed Jul 29 07:15:29 1998
From: dslater at ix.netcom.com (Dan Slater)
Date: Tue, 28 Jul 1998 22:15:29 -0700
Subject: Dan Slater's Article in CMJ, and X to the kth power - how do you do it?
References: <35BE89D7.B906928C@seanet.com>
Message-ID: <35BEAFF1.3935@ix.netcom.com>

Sean Costello wrote:
> 
> Hi all:
> 
> The new Computer Music Journal (Volume 22, Number 2, Summer 1998)
> finally hit the stands.  Dan Slater has a fascinating article in it -
> "Chaotic Sound Systems."  Y'all gotta track it down.
> 
> Anyway, Mr. Slater describes a hypothetical Buchla module (complete with
> an "artist's conception" that points out how truly beautiful the Buchla
> 200 designs were visually) that would implement a Ueda Attractor. As
> described, the Ueda attractor circuit is very similar to a
> state-variable filter, but with the inverting stage replaced with an x^3
> stage (x cubed) and the signal input connected to the first integrator
> stage.  Slater's hypothetical module uses an x to the k function, where
> the circuit can be converted from a state variable topology to an Ueda
> Attractor by changing the value of k (for a state-variable filter, k=1;
> for the Ueda attractor, k=3).
> 
> How the heck would you do this?  Is there some common circuit that
> produces an x to the k function, where k can smoothly vary (i.e. by
> non-integer values) between 1 and 4?  x^1 is simple; x^2 could be a
> multiplier where the input is multiplied by itself; x^3 could be created
> by a second multiplier multiplying the input by the product of an x^2
> stage.  But how do you get, say, x^2.74?  And how do you vary these
> smoothly?  Could you use feedback from a multiplying stage, where a
> signal is multiplied by the output of the multiplier?  Or maybe feedback
> in a 2-multiplier configuration?
> 
> As always, any and all advice welcome.  I think that this would be a
> cool circuit to own.
> 
> Thanks,
> 
> Sean Costello

Hi Sean;

	Thanks for the kind words;

	A relatively simple approach for the x^k is to have a voltage
controlled multiplexer that selects between the various integer exponent
values from 0, 1 or 2 multipliers. Even this can be interesting as the
exponent is swept between different quantized values.

	Non integer exponents can be handled by taking the log of the signal,
multiplying by the exponent and then taking the inverse log
(exponential) of the signal.

	x^n = exp (n * ln(x))

	A problem here is that you can not take the log of a negative number.
One possible solution is to full wave rectify the signal prior to the
log operation and restoring the sign after the exponential operation.

	In my experience to date, I have just used the x^3 configuration as
formed by a pair of multipliers. I have not yet implemented the variable
exponent.

Good luck;

Dan Slater



From martin.czech at intermetall.de  Wed Jul 29 08:59:50 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Wed, 29 Jul 1998 08:59:50 +0200 (MET DST)
Subject: Dan Slater's Article in CMJ, and X to the kth power - how do you do it?
Message-ID: <199807290659.IAA12744@window.intermetall.de>

>> state-variable filter, but with the inverting stage replaced with an x^3
> stage (x cubed) and the signal input connected to the first integrator
> stage.  Slater's hypothetical module uses an x to the k function, where
> the circuit can be converted from a state variable topology to an Ueda
> Attractor by changing the value of k (for a state-variable filter, k=1;
> for the Ueda attractor, k=3).
> 
> How the heck would you do this?  Is there some common circuit that
> produces an x to the k function, where k can smoothly vary (i.e. by
> non-integer values) between 1 and 4?  x^1 is simple; x^2 could be a
> multiplier where the input is multiplied by itself; x^3 could be created
> by a second multiplier multiplying the input by the product of an x^2
> stage.  But how do you get, say, x^2.74?  And how do you vary these
> smoothly?  Could you use feedback from a multiplying stage, where a
> signal is multiplied by the output of the multiplier?  Or maybe feedback
> in a 2-multiplier configuration?
> 

I can't see how feedback will change the order of the circuit equation.

Stupid 1st order approach:

since log(x^k)=k*log(x)

x^k=exp{log(x^k)}=exp{k*log(x)}

a log,exp and multiplier circuit. And lots of problems: works only for x^k > 0.  A full-wave rectifier could enshure x^k >=0, the equal sign could
be avoided with some comparator logic, ie. for very small |x| ~ 0
another circuit could be switched in.  Ok, too complicated, not steady
arround 0. Next candidate , please.

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 aschrock at cs.brandeis.edu  Wed Jul 29 09:05:08 1998
From: aschrock at cs.brandeis.edu (Andrew Schrock)
Date: Wed, 29 Jul 1998 03:05:08 -0400 (EDT)
Subject: another (US) Schaeffer-Apparatebau report
In-Reply-To: <199807281320250530.0124D1FD@mail.proaxis.com>
Message-ID: <Pine.HPP.3.95.980729025817.3100A-100000@bay.cs.brandeis.edu>

On Tue, 28 Jul 1998, Jim Johnson wrote:
> Designer? I've fiddled with it a bit, but not too seriously, because I
> don't have time to dive into a project right now. I'd like to get a sense
> of what's possible with it. (I'd like to do things like replace the fonts,
> add graphics, radial lines for the knobs, etc., but I can't see how to do
> these things in the version I've got.) 

Well, you sorta can't do the things you mention as far as I know. As for
radial lines and graphics, I have no need for them... I guess a logo might
be spiffy, but I don't really need it. Lines for the dials would also be
nice, but IMO with single-turn knobs there's not too much of a need.. There
has to be a way to do this sort of thing, you should just call or email
them if you're really interested. 

Kai tells me that they now have facilities for charging via VISA and
(soon) Mastercard! This makes them much more convenient to us US folks, as
it's a pain to shell out $30 for the wire transfer payment. (shipping is
50 DM, which isn't too bad at all) 

Andrew

| Andrew Schrock							|
| Network Programmer, Synthesizer and electronic music enthusiast	|
| aschrock at cs.brandeis.edu						|





From pfperry at melbpc.org.au  Wed Jul 29 10:37:11 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 29 Jul 1998 18:37:11 +1000 (EST)
Subject: Dan Slater's Article in CMJ, and X to the kth power - how
  do you do it?
Message-ID: <1.5.4.16.19961221011232.37c75854@popa.melbpc.org.au>

At 07:32 PM 28/07/98 -0700, Sean Costello  wrote:

>stage.  Slater's hypothetical module uses an x to the k function, where
>the circuit can be converted from a state variable topology to an Ueda
>Attractor by changing the value of k (for a state-variable filter, k=1;
>for the Ueda attractor, k=3).
>
>How the heck would you do this?  Is there some common circuit that
>produces an x to the k function, where k can smoothly vary (i.e. by
>non-integer values) between 1 and 4?  

well check out the old Burr-Brown application book..

but, what you need is a log convertor, a multiplier (or a pot, if you
are doing it by hand) and an exponentiator.
If you are happy with a fairly rough one without temperature compensation,
it isn't too hard.
Any book like Horowitz & Hill or Jung's Op Amp Cookbook will have the
rudiments.

good luck from paul perry melbourne australia




From steevcoc at world.std.com  Wed Jul 29 16:10:56 1998
From: steevcoc at world.std.com (SteevCoco)
Date: Wed, 29 Jul 1998 10:10:56 -0400
Subject: NewBie Question:  Trigger-To-MIDI DIY?
Message-ID: <199807291410.AA29302@world.std.com>

Hi all,

I'm new to the list, so I don't know if this kind of stuff is discussed 
here, but...

I'm working on an art project and I need to find the cheapest 
trigger-to-MIDI device I can.  I don't know if I can get parts to build 
one myself or not.  Anyone done this before?  I don't need anything fancy 
- simple switches is all, but making MIDI from that is beyond me.

Thanks in advance.

Peace,  -Steev


 ________________________ __________________________________
|                        |                                  |
  SteevCoco                3 Hillside Ave
  bigSun                   Boston, MA 02130-4122
 <steevcoc at world.std.com> <http://world.std.com/%7Esteevcoc>
|________________________|__________________________________|




From b.layer at vikingelectronics.com  Wed Jul 29 17:28:46 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 29 Jul 1998 10:28:46 -0500
Subject: PC Hardware
Message-ID: <3.0.5.32.19980729102846.007a27c0@192.168.210.18>

Hi All,

Is anyone on the list an IBM PC 'expert'? I've got an oddball question,
that only experience can answer. 

If not, could someone point me to the right list for IBM hardware problem
solving?

Since this is offtopic, please respond via personal email.

Thanks!




From tic at vossnet.de  Wed Jul 29 18:38:41 1998
From: tic at vossnet.de (tim0 (Timo Christ))
Date: Wed, 29 Jul 1998 18:38:41 +0200
Subject: please help with PSU  :-((
Message-ID: <35BF5010.2DBB2094@vossnet.de>

Hi, 

i?m a bloody beginner and started working on my little synth last week.
the first thing i built was /is the PSU, after lots of trial and error
and i have learned from mistakes :) it still doesn?t work.
to be precise, the -15 V regualted output doesn?t work. 

i hope you guys can help me, thanks so much for your time.

it is a very simple design, based on a 7915. here comes the description:

230V prim to 2x 18 V secondary torroid transformer, B250C2300-1500
bridge rectifier -AC+; the  - (-)goes directly to the input of the 7915,
AC is connected to the transformer and the + output (+) is connected to
the ground. a 2200uF capacitor is connected with the negative side to
the - power line to the 7915 and the positive lead to GND. 

i hope this shows how the components are connected:

          (-)
           |
           |---. -
           |   2200uF
 Output--7915--?-------(+)---GND (mains)

the whole thing is not connected to anything else.
+15 V and +5V works, it is the same design only the outs of the bridge
rectifier are reversed. i don?t understand why it doesn?t work. :-(((

i feel really stupid asking such a simple question on this list, but
please help.
Thanks very much, 
Timo
-- 
Timo Christ -- Germany -- Europe
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net




From ebarbour at svetlana.com  Wed Jul 29 20:13:33 1998
From: ebarbour at svetlana.com (Eric Barbour)
Date: Wed, 29 Jul 1998 11:13:33 -0700
Subject: NewBie Question:  Trigger-To-MIDI DIY?
Message-ID: <01BDBAE1.ED100560.ebarbour@svetlana.com>

Try this:

http://www.calpoly.edu/~cwoodwor/midi.html

Some of the companies listed there make keyboard-to-MIDI
adapters as well as MIDI-to-organ circuits. (be prepared to
spend a couple hundred dollars. There's not much chance of
finding a cheaper device to do it, except possibly
buying an old MIDI-output combo keyboard in the
used-equipment market, and gutting its circuits to
wire to your switches.)


Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA




From kayana at pacbell.net  Wed Jul 29 20:57:54 1998
From: kayana at pacbell.net (kayana at pacbell.net)
Date: Wed, 29 Jul 1998 20:57:54 +0200
Subject: Bad noise emissions and cleaning pots.
References: <199807291410.AA29302@world.std.com>
Message-ID: <35BF70B2.1193@pacbell.net>

I have two problems with synths. My moog prodigy emits a constant 
noise, it is probbaly bad connections or dirt but i am new to this. 
The wire that needed to be grounded was not when i opened it up, i 
then regrounded it. The noise remainede

My moog mg-1 will not pla y like a piano ie it will not use and 
envelope in either keyed or contour. The "fall" ffunction does not 
appear to work but it may also be the auto contour or sustain in/out. 
The only way it works it a continous signal. How do i clean the fall 
or ewtc. 

thanks a bunch todd



From b.layer at vikingelectronics.com  Wed Jul 29 21:45:58 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 29 Jul 1998 14:45:58 -0500
Subject: IBM PC Hardware
Message-ID: <3.0.5.32.19980729144558.007a84e0@192.168.210.18>

All,

This has got to be the most intelligent, helpful group on the net. I've
gotten half a dozen good replies so far, and please keep the opinions
coming...






From oakley at enterprise.net  Wed Jul 29 22:00:22 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Wed, 29 Jul 1998 21:00:22 +0100
Subject: This is a long one.
Message-ID: <000d01bdbb2e$0a5e8be0$24c548c2@default>

Hi all,

Since I have finished my monosynth, I have had a few enquiries about what
useful things I found out in the construction. In a switched linked synth
the number of routing permutations will be limited by the number of switches
and pots. No patch leads here. But I have ended up with 40 switches and 54
pots. The basic architecture of one channel is two VCOs feeding one VCF
feeding one VCA. Two ADSR generators are used to control the VCF and VCA.
The synth contains two channels. Both channels can work in parallel on
separate MIDI channels, i.e.. two separate synths. Or, one MIDI channel can
operate both, i.e.. a two VCF, four VCO synth. The VCFs can work in parallel
on all four VCOs or separately.

So what do I really think are essential things to include? FM and AM for one
of the pair of VCOs; this is good. FM of the filter cut off, this is great.
Hard sync is essential, but even more so if you get the sync'd VCO to sweep
with the ADSR. Don't bother with negative going sweeps. The hard sync on the
CEM VCOs is actually quite good. Multi mode filters with HP as well as LP.
The Moog ladder is there as well for those mellow moments. Pulse width
modulation controlled by ADSR, I love this one. Delayed LFO is great for
vibrato, but a waste for the VCF's LFO. Be sure to include fine tuning, I
didn't and have tune pots that span two and half octaves... ouch. White
noise I generated with a shift register, I could not get noisy sources to
work at all well. Alternate noise source which is a clone of the cymbal unit
in an early Roland drumbox, this is great for high-hat wickedness. This
feeds straight into each of the VCFs. Don't bother with keyboard tracking
for the ADSRs... its not worth it, unless you've got a load of CEM3310s.
Velocity drive on the filter cut-off, yes. Full and half wave on the VCO on
the triangle outputs is great too.

And what about the front panel.... 6mm MDF and painted black with
plasticote. No labels since I built the thing and know what each one does.
Low cost collet knobs, colour coded. I would recommend the miniature toggle
switches from Farnell, pt no. 958-906 SPDT.






From b.layer at vikingelectronics.com  Wed Jul 29 22:11:47 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Wed, 29 Jul 1998 15:11:47 -0500
Subject: NewBie Question:  Trigger-To-MIDI DIY?
In-Reply-To: <01BDBAE1.ED100560.ebarbour@svetlana.com>
Message-ID: <3.0.5.32.19980729151147.007acde0@192.168.210.18>

Hi Todd,

 (be prepared to
>spend a couple hundred dollars. There's not much chance of
>finding a cheaper device to do it, except possibly
>buying an old MIDI-output combo keyboard in the
>used-equipment market, and gutting its circuits to
>wire to your switches.)

I can't overstate the functionality and outright cheapness of my Quick-Shot
MIDI controller. This is a FULL function unit, with tons of control
options, easy data entry via a quantized analog data entry slider pot, and
4 octave velocity-sensitive keyboard, which may be set to control any of 12
ranges. 

They can be purchased (through Music-Go-Round for instance) for $129.00,
INCLUDING a full CD version of the CakeWalk home studio ($39.95, at least).
Not only does this unit provide a standard MIDI out, but it sports an
internal MIDI interface that is plug-compatible with the 'joyport' on most
PC sound cards, for quick and sleazy PC based sequencing.

 Don't want to sacrifice your joystick to a keyboard? That's ok, because
the Quick-Shot has a thru connector for the joystick, as well.

When connected to a PC sound card, the unit required no additional power
supply. 

I guess I like it; unusual for me and a commercial device. 

Good Luck!





From PapaJ59871 at aol.com  Wed Jul 29 22:40:38 1998
From: PapaJ59871 at aol.com (PapaJ59871 at aol.com)
Date: Wed, 29 Jul 1998 16:40:38 EDT
Subject: NewBie Question:  Trigger-To-MIDI DIY?
Message-ID: <77874e51.35bf88c7@aol.com>

In a message dated 98-07-29 10:35:26 EDT, steevcoc at world.std.com writes:

<< I'm working on an art project and I need to find the cheapest 
 trigger-to-MIDI device I can.   >>

Try http://www.paia.com/midibrn.htm - can be used either as MIDI fader or Drum
Brain kind of thing. Inexpensive, easy, might be what you're looking for.

-JS



From keen at austin.ibm.com  Thu Jul 30 00:03:56 1998
From: keen at austin.ibm.com (R.G. Keen)
Date: Wed, 29 Jul 98 17:03:56 -0500
Subject: Matching Diodes, & filter FM 
In-Reply-To: (Your message of Tue, 28 Jul 98 15:21:34 -0700.)
             <35BE4EEE.68EEECD0@seanet.com>
Message-ID: <199807292203.RAA32294@keen.austin.ibm.com>

In the PCB that I got done for the "stock" diode ladder, I had room 
for the 7660 +9 to -9 converter, so the dual batteries may be optional. 



From steve at babcom.u-net.com  Thu Jul 30 00:16:16 1998
From: steve at babcom.u-net.com (Steven Cook)
Date: Wed, 29 Jul 1998 23:16:16 +0100
Subject: Matching Diodes, & filter FM
References: <35BE4EEE.68EEECD0@seanet.com>
Message-ID: <35BF9F30.65EC7EAB@babcom.u-net.com>

Sean Costello wrote:
> 
> Hi folks:
> 
> I am currently breadboarding a diode ladder filter.
> 
> 1) How should I go about matching the diodes in the circuit?  I have a
> new multimeter, & a good breadboard w/a power supply (+12V, -12V, +5V),
> so any simple circuits would be appreciated.

> I have high hopes for this little box.  It will be based on a Practical
> Electronics design, powered by 2 9V batteries, and should fit in a
> Hammond 1590BB box when finished.
> Sean Costello

I've just built a transistor ladder filter without matching anything and it
seems fine - no noticeable dc breakthrough. Might be worth trying.

Is your filter the one from the Minisonic? I built one years ago and remember
it having a really warm sound.

I used to mix the output of this filter with the input signal, which cancelled
out when trimmed just right, leaving (I think) a sort of highpass response.

Good luck!

Steve.




From oakley at enterprise.net  Thu Jul 30 00:32:29 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Wed, 29 Jul 1998 23:32:29 +0100
Subject: please help with PSU  :-((
Message-ID: <003c01bdbb40$c7e33820$7cc448c2@default>

Dont forget Timo that the pin out for the 7915 is different to the 7815. The
tab on the ic is the most negative, ie. the GND on the 7815 and input on the
7915. As you look at 7915, tab on the underside, pins towards you, Ground,
input, output.

However, you may know this already.

Secondly, you need a 2u2 electrolytic/tantulum capacitor connecting the
output of the 7915 to ground. See the data sheet at the National
Semiconductor site or try Farnell's on-line data sheets.

Regards,

Tony

-----Original Message-----
From: tim0 (Timo Christ) <tic at vossnet.de>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Wednesday, July 29, 1998 10:29 PM
Subject: please help with PSU :-((


Hi,

i?m a bloody beginner and started working on my little synth last week.
the first thing i built was /is the PSU, after lots of trial and error
and i have learned from mistakes :) it still doesn?t work.
to be precise, the -15 V regualted output doesn?t work.

i hope you guys can help me, thanks so much for your time.

it is a very simple design, based on a 7915. here comes the description:

230V prim to 2x 18 V secondary torroid transformer, B250C2300-1500
bridge rectifier -AC+; the  - (-)goes directly to the input of the 7915,
AC is connected to the transformer and the + output (+) is connected to
the ground. a 2200uF capacitor is connected with the negative side to
the - power line to the 7915 and the positive lead to GND.

i hope this shows how the components are connected:

          (-)
           |
           |---. -
           |   2200uF
Output--7915--?-------(+)---GND (mains)

the whole thing is not connected to anything else.
+15 V and +5V works, it is the same design only the outs of the bridge
rectifier are reversed. i don?t understand why it doesn?t work. :-(((

i feel really stupid asking such a simple question on this list, but
please help.
Thanks very much,
Timo
--
Timo Christ -- Germany -- Europe
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net









From tic at vossnet.de  Thu Jul 30 00:35:58 1998
From: tic at vossnet.de (tim0 (Timo Christ))
Date: Thu, 30 Jul 1998 00:35:58 +0200
Subject: please help with PSU  :-((
References: <35BF5010.2DBB2094@vossnet.de> <35BF9697.446B@ptdcs2.intel.com>
Message-ID: <35BFA3CE.486B7CD9@vossnet.de>

Hi Duane, 

thanks for the reply.

Duane R Balvage wrote:
<<snip>> my message [-15V Out on my PSU doesn?t work]
>    A-HA! Here is your problem!
> 
>    The filter cap goes BEFORE the regulator, not after. This is why it
> doesn't work.

the filter cap is before the regulator.


> 
>    Your PS *should* look like this:

thanks for the illustration, my PS uses one bridge rectifier for each
output,
so my PS has three.
I have modified your nice ascii-art to show how my PS looks now:

>                                 +-------+       
>                            (+)  |       | 
>   -----) | | (---------+-----+--+      ---
>  mains(  | |  )        | B.R.|  |       - mains ground
>        ) | | (         |     |  |
>       (  | |  ) 18V    |     |  |
>        ) | | (        ++-----+  | 
>       (  | |  )       |   (-)|  +---------+-------+------>
>        ) | | (        |      |            |2200uF |           
>       (  | |  )       |      |           ---      |        0v (out)
>   -----) | | (--------+      |           ---      |          
>                              |            |    +--+---+    
>                              |            |    |      |       
>                              +------------+----+ 7915 +--> -V
>                                                |      |
>                                                +------+
> 
> * B.R. = Bridge Rectifier
> 
>   BTW, the 7915 pinout is a little different - I'm pretty sure the GND
> pin is on the right, and not in the middle...

i got the pinouts right.

please tell me if the design is ok and some part  is defective (reg or
BR) or if there is some terribly stupid idiot-me design error. :-(

thanks for your time,
Timo
-- 
Timo Christ -- Germany -- Europe
root at dist0rter -- tic at vossnet.de -- LEDflash at gmx.net




From verbos at on-q.com  Thu Jul 30 01:06:06 1998
From: verbos at on-q.com (mark verbos)
Date: Wed, 29 Jul 1998 17:06:06 -0600
Subject: (G-TECH) alias database as of 29-07-1998
References: <Pine.BSF.3.96.980729143939.18871B-100000@soda.CSUA.Berkeley.EDU>
Message-ID: <35BFAAD9.B6210F46@on-q.com>

No. Akilah Bryant is Ron Maney's wife. she indeed makes the
tracks too.

Eli Bingham wrote:

> DJ Skull = Alikah Bryant (??!??)
>
> -Eli


--
mark verbos

"I think the future of analog modulars is to build them
yourself."

verbos at on-q.com
http://www.on-q.com/verbos
massive magazine... http://www.massivemag.com
current release...
 "Logic Circuits" as CMOS on Shokoy, Germany





From Juergen.Haible at nbgm.siemens.de  Thu Jul 30 13:44:04 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Thu, 30 Jul 1998 13:44:04 +0200
Subject: useful VCADSR's (was:This is a long one.)
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D5828F0F9D@nbgm336a.nbgm.siemens.de>

	> Don't bother with keyboard tracking
	> for the ADSRs... its not worth it, unless you've got a load of
CEM3310s.

Joachim has published a very interesting VC envelope recently.
No need for 3310's (;->).

VC Decay and VC Sustain can be extremely useful for fast sequencer
and arpeggiator patterns. Use a slow LFO or a S&H that is synced to
the sequencer / arpeggiator as modulation source.

In case you really want to use keyboard tracking on ADSR parameters,
make sure that you can invert the modulation source. You can read that
shorter decay times for higher notes make a sound more "realistic",
but I think this effect is not very convincing. The opposite (slower attack
and decay for higher notes) allows a punchy bass at the low end, and 
a soaring lead sound at the high end of the keyboard. Try it; you'll like it
!

JH. 




From steevcoc at world.std.com  Thu Jul 30 15:26:22 1998
From: steevcoc at world.std.com (SteevCoco)
Date: Thu, 30 Jul 1998 09:26:22 -0400
Subject: NewBie Question:  Trigger-To-MIDI DIY?
Message-ID: <199807301326.AA04118@world.std.com>

Mark Glinsky may have said:

>Probably more than you want to spend, but I have a Simmons TMI
>that I'm selling:

Thanks a bunch, but you're right! ;-)


Joe Miklojcik may hava said:

>For DIY kits along the lines you're looking for, check out
>
>www.pavo.com
>
>www.paia.com

That helps.  In the end, I may have better luck (read: cheaper) finding 
something used and ripping it open!  But the "Drum Brain" on the PAIA 
site is essentially just what I'm looking for.

Thanks for all the help.  I'll let you all know how it turns out...

Peace,  -Steev


 ________________________ __________________________________
|                        |                                  |
  SteevCoco                3 Hillside Ave
  bigSun                   Boston, MA 02130-4122
 <steevcoc at world.std.com> <http://world.std.com/%7Esteevcoc>
|________________________|__________________________________|




From b.layer at vikingelectronics.com  Thu Jul 30 15:43:20 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Thu, 30 Jul 1998 08:43:20 -0500
Subject: PC Hardware prob. *SOLVED*
Message-ID: <3.0.5.32.19980730084320.0079de40@192.168.210.18>

Hi, and thanks to everyone who lent assistance.

The IBM hardware dilemma is solved, and my machine is now running on 48+MB

An insightful reply from Steve Crippen lead me to the Deja News IBM PS/2
hardware group, where I was able to contact an extremely helpful German
fellow named Peter Wendt. 

Peter gave me the missing information (make that esoterica) in the form of
an email with attached jpeg. Two (tiny!) solder joints later... success was
mine!

If anyone who lent assistance would like to examine the answer I received,
for their own information, send me an email requesting 'PC hardware
solution' and I'll forward a copy of Peter's info.

Thanks again everyone.





From johns at oei.com  Thu Jul 30 17:02:21 1998
From: johns at oei.com (John Speth)
Date: Thu, 30 Jul 1998 08:02:21 -0700
Subject: Cover vinyl source?
In-Reply-To: <3.0.1.32.19980728221533.00b4de34@mail.kc.net>
Message-ID: <000101bdbbcb$0d7887c0$2c15d7d0@johns.oei.com>

Thanks for all the great replies.  To summarize, here's what I found.

The stuff is called Tolex (a trade name).  Some guess it's just vinyl but
it's probably a toughened up version.  It comes in many colors and is the
brand of choice for Fender and probably many others.  You apply it using
contact cement and Duane Balvage suggests using a hair dryer to soften it
around corners.

You can mail order from Antique Electronics Supply
(http://www.tubesandmore.com/) for $10/ft (54 inch wide).  If you live near
Portand, OR you can get it from Pat, a cabinet maker, for $25/yard (54 inch
wide) at Eagleworks at 503-236-3733.  Many repliers suggest that many amp
repair/restoration shops and even some better amp retailers can sell you
some as well as other goodies like corner bumpers, etc.

John Speth
Object Engineering, Inc
mailto:johns at oei.com





From amieuss at telcel.net.ve  Thu Jul 30 17:37:16 1998
From: amieuss at telcel.net.ve (Arturo Mieussens)
Date: Thu, 30 Jul 1998 11:37:16 -0400
Subject: chorus pedal IC's
Message-ID: <19980730153729.AAA6715@smarty.telcel.net.ve@telcel.telcel.net.ve>

I have an ampeg chorus pedal with a couple of bad IC's, MN3009 and MN3101.

What are those and where can I find them?.

Thanks in advance.

Arturo

amieuss at telcel.net.ve



From oakley at enterprise.net  Thu Jul 30 20:59:52 1998
From: oakley at enterprise.net (Tony Allgood)
Date: Thu, 30 Jul 1998 19:59:52 +0100
Subject: useful VCADSR's (was:This is a long one.)
Message-ID: <000a01bdbd24$c8f650e0$a7c548c2@default>

Jeurgen said:
In case you really want to use keyboard tracking on ADSR parameters,
make sure that you can invert the modulation source. You can read that
shorter decay times for higher notes make a sound more "realistic",
but I think this effect is not very convincing. The opposite (slower attack
and decay for higher notes) allows a punchy bass at the low end, and
a soaring lead sound at the high end of the keyboard. Try it; you'll like it
!

Oh no, another little board to fit inside my monosynth!!
Where's my hot glue gun? :-)

Regards,

Tony Allgood, Cumbria, UK

e-mail: oakley at enterprise.net

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  Fri Jul 31 04:57:41 1998
From: cyborg0 at GlobalEyes.net (cyborg0 at GlobalEyes.net)
Date: Thu, 30 Jul 1998 21:57:41 -0500
Subject: Another Syntecno post... DIY?
Message-ID: <35C132A5.63CF519B@globaleyes.net>

ok, heres the deal.. 
I have found 2 things that I THINK may attribute to the TeeBee's
excellent but not perfect simulation of a tb303

Some of the things that sound different have to to with mainly the fact
that, with all knobs left except cutoff (full right) it doesnt sound
right..ie, it doesnt sound like any of the tb303s ive compared it to. It
doesnt have the same *raspiness* and *growl*(tm) :))
I think this may be the lack of the ol ba662 in the VCA..but it could
be...

1) that "aggressiveness" pot was, I believe, actually the other side of
the resonance pot on the 303..Ive yet to confirm this totally.
Perhaps hooking this up will the sound better at hi cutoff and give it
more grit.

2) the filter outputs a y-axis symmetrical voltage swings in the
waveform.
|\    |\     
| \   | \   
   | /   | /             
   |/    |/                 

 unlike the original tb303, where, at TP-6, the waveform is only
asymmetrical, ie the saw wave still looks exactly like the original saw
wave being fed into the filter.
|\ |\     
| \| \   



 Im sure the same harmonics are present, but I wonder what effect this
has on the input to the VCA?
This might also be it..

One other thing.. sometimes, esp when using SEQ303 (which is a GREAT
program BTW) I notice that I can program a sequence exactly the way it
is in a 303, and, for some reason, the sequence sounds exact, BUT, the
notes seem kinda *stiff*. Anyone know a reason for this?
i looked at wave files for each one playing the same sequence, and I
could find NO timing difference in either the start of the frequency
change (for slide) or the note start..
anyone care to comment?
Anyone notice any of these things?
rob



From 9705146x at lux.levels.unisa.edu.au  Fri Jul 31 05:12:48 1998
From: 9705146x at lux.levels.unisa.edu.au (9705146x)
Date: Fri, 31 Jul 1998 12:42:48 +0930 (CST)
Subject: VCO idea
Message-ID: <Pine.SOL.3.91.980731123319.23696B-100000@lux.levels.unisa.edu.au>

I was just sitting in an electronics lecture and had an idea for a VCO. 
Why not have a repeating waveform that has (say) 4 "lines" of which the 
slope and duration can be adjusted, either by a control knob or voltage 
control. Like this :
        |         |
       / \_       |
\     |    \_     |
 \   /       \_   |
  \  |       ^ \_ |
   \/        |   \|
 ^    ^      |     
 |    |      |    ^
Line1 |     Line3 |
      |           |
    Line2        Line4 


So, in other words, you would have a waveform which has a  constantly 
changing waveform. You could modulate the amplitudes and slopes of the 
lines in any way you wanted creating very strange waveforms. How would 
one go about building a circuit that could do this? Could it be done 
using analogue electronics? Has anything like this ever been incorperated 
in a Serge, Buchla, or Moog modulars?

<bUd> Board shitless in another Computer Systems Engineering lecture ;(



From martin.czech at intermetall.de  Fri Jul 31 08:34:03 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 31 Jul 1998 08:34:03 +0200 (MET DST)
Subject: chorus pedal IC's
Message-ID: <199807310634.IAA28706@window.intermetall.de>

> I have an ampeg chorus pedal with a couple of bad IC's, MN3009 and MN3101.
> 
> What are those and where can I find them?.
> 
Maybe very expensive in repair shops (also on the internet, try a
search machine).

RS Components have some MN300x BBDs, but not exactly the type you ask
for. They have also a 3000 stage part, for arround 100 DM. Maybe you
could contact the RS service and try to find the local panasonic
distributor. I also tryed the panasonic/matsushita web page, no way.  I
guess it's the same with Analog Devices. Some parts are still in
production somehow, but the don't appear in datasheets or catalogues
any more.

Is this called silent death of an analogue ;->?

m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style





From martin.czech at intermetall.de  Fri Jul 31 09:03:29 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 31 Jul 1998 09:03:29 +0200 (MET DST)
Subject: VCO idea
Message-ID: <199807310703.JAA28777@window.intermetall.de>

> I was just sitting in an electronics lecture and had an idea for a VCO. 
> Why not have a repeating waveform that has (say) 4 "lines" of which the 
> slope and duration can be adjusted, either by a control knob or voltage 
> control. Like this :
>         |         |
>        / \_       |
> \     |    \_     |
>  \   /       \_   |
>   \  |       ^ \_ |
>    \/        |   \|
>  ^    ^      |     
>  |    |      |    ^
> Line1 |     Line3 |
>       |           |
>     Line2        Line4 
> 
> 
> So, in other words, you would have a waveform which has a  constantly 
> changing waveform. You could modulate the amplitudes and slopes of the 
> lines in any way you wanted creating very strange waveforms. How would 
> one go about building a circuit that could do this? Could it be done 
> using analogue electronics? Has anything like this ever been incorperated 
> in a Serge, Buchla, or Moog modulars?

I don't want to discourage you, but ... I toyed arround a lot with hand
made waves and wavetables for the Waldorf Microwave I (No, I won't swap
it against a Microwave II or XT) and came to the conclusion that in a
lot of cases the results are not very exciting, certainly there are
differences in sound, but I expected something to knock me off my
chair, and this really happens, but not very often.

What you are proposing is a "piecewise linear function" PLF, if I got
it right.  A sawtooth wave is feed into some black box, and a PLF comes
out.  This can be done using half wave precision rectifiers HWPR. This
is a standard circuit you'll find in any good book about opamps and
analogue computing.  You need one HWPR for every break in your curve.
You feed the sawtooth wave into each HWPR and a some offset (at the
desired breakpoint)  at each HWPR. The result is that the HWPR turn on
one after the other, just as it is specified by the offset voltages.
You now take the output of each HWPR and go into "bipolar coefficient"
boxes. These are analogue computing modules that multiply the input
with a constant k , -1 < k < 1. Finally all these voltages are added
together and voila there's the PLF.

Problems: Most PLF won't be spectacular. If you want a non monotonic
PLF (like a triangle, first up, then downwards) this means the the
coefficient for the first breakpoint is 0.5, and for the next it has to
be -1. Remember that both coefficient outputs are added together, first
you have only a factor of 0.5 then the second HWPR turn on (0.5 +
(-1))=-0.5.  This example shows some limitation, if you need wild
nonmonotonic breaks (and these waves sound exciting, there is a
tendency for smaller coefficients.  And: every segment depends on all
predecessor segments. It's not like drawing the waveform with the
mouse.

As I said, the nonmonotonic PLF are of most interest, because they can
produce really strange harmonics. Take for instance a PLF that looks
like a long piece of triangle wave. Say 7 cycles. If you vary the input
amplitude of the incomming saw, you first get a  saw wave, this changes
into a tri, and later you get waves with very small fundamental but
very strong harmonics, up to 7th order, the final stage is a tri wave
seven times faster then the incimming saw.

Is this the principal of the Serge waveshaper?

Anyway, you can try this with the Nord Modular, it comes close to "FM"
sounds, when the carrier is set to 0Hz fixed.

Hope this helps.

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 pfperry at melbpc.org.au  Fri Jul 31 09:30:10 1998
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 31 Jul 1998 17:30:10 +1000 (EST)
Subject: VCO idea
Message-ID: <1.5.4.16.19961223000530.304facd2@popa.melbpc.org.au>

At 12:42 PM 31/07/98 +0930, <bUd> Board shitless  wrote:
>I was just sitting in an electronics lecture and had an idea for a VCO...

to get a rough idea what this sounds like, you can make an approximation 
from a stepped analog sequencer run at audio frequencies. (The roland 
system 100 gets up at lest into the bottom of the audio range).
Not very fat, since the harmonics generated are all precisely locked to the 
fundamental. But, if you were poling around voltages that had some slow
variation added to them, then you might get something interesting.

paul perry melb australia 
"Aliasing.. the new groundbreaking synth generator technique!"




From boldman at interplanet.it  Fri Jul 31 10:11:43 1998
From: boldman at interplanet.it (riccardo)
Date: Fri, 31 Jul 1998 09:11:43 +0100
Subject: PS3300
Message-ID: <l03102800b1e72c303f3b@[192.106.97.205]>

Hi,
I recently bought a Korg PS3300.
It works quite nice but would need some recalibrations.
Is there anyone who can provide a copy of both service and owner's manual
for this unit?
Of course, payment for the copies is due.
cheers
riccardo





From Colin.Fraser at scottishpower.plc.uk  Fri Jul 31 10:46:25 1998
From: Colin.Fraser at scottishpower.plc.uk (Fraser, Colin J)
Date: Fri, 31 Jul 1998 09:46:25 +0100
Subject: Another Syntecno post... DIY?
Message-ID: <81880CC73125D211BC6800805F0D83070BD8@spresource.cat.scottishpower.plc.uk>

> -----Original Message-----
> From: cyborg0 at GlobalEyes.net [mailto:cyborg0 at GlobalEyes.net]
> Sent: 31 July 1998 03:58
> To: analogue at hyperreal.org; synth-diy
> Subject: Another Syntecno post... DIY?
> 
> 
> ok, heres the deal.. 
> I have found 2 things that I THINK may attribute to the TeeBee's
> excellent but not perfect simulation of a tb303
> 
> Some of the things that sound different have to to with 
> mainly the fact
> that, with all knobs left except cutoff (full right) it doesnt sound
> right..ie, it doesnt sound like any of the tb303s ive 
> compared it to. It
> doesnt have the same *raspiness* and *growl*(tm) :))
> I think this may be the lack of the ol ba662 in the VCA..but it could
> be...

I used BA662 in my clone, and it still doesn't sound *exactly* like my
real 303, but is so close that you can't say which is which.
This would possibly be the case with another real 303...

> One other thing.. sometimes, esp when using SEQ303 (which is a GREAT
> program BTW) I notice that I can program a sequence exactly the way it
> is in a 303, and, for some reason, the sequence sounds exact, BUT, the
> notes seem kinda *stiff*. Anyone know a reason for this?
> i looked at wave files for each one playing the same sequence, and I
> could find NO timing difference in either the start of the frequency
> change (for slide) or the note start..
> anyone care to comment?
> Anyone notice any of these things?
> rob

Yes, I noticed these things too, with Seq303 and Cubase, and spent some
time listening to it, and thinking about it.
I posted about this to synth-diy before, and the post is copied on the
303 web site at http://www.teknet.ch/tb-303/speaking/art09.htm
Have a look there if you want - I'll not waste b/w by reposting the
whole thing.

Colin f






From PapaJ59871 at aol.com  Fri Jul 31 11:19:23 1998
From: PapaJ59871 at aol.com (PapaJ59871 at aol.com)
Date: Fri, 31 Jul 1998 05:19:23 EDT
Subject: VCO idea
Message-ID: <a5dee5cd.35c18c1c@aol.com>

In a message dated 98-07-31 03:25:01 EDT, martin.czech at intermetall.de writes:

<< toyed arround a lot with hand
 made waves and wavetables for the Waldorf Microwave I (No, I won't swap
 it against a Microwave II or XT) and came to the conclusion that in a
 lot of cases the results are not very exciting, >>

Any static waveform, no matter how complex, will ultimately sound like an
organ. It's animation and modulation that make them interesting. If the
voltage controlled segment part of the original post was implemented it would
probably be pretty cool but the basic ramp, triangle, sine and pulse pretty
much cover all the bases otherwise. It's when you start changing these over
time, either with filters or by modulating the pulse width for example, that
things get interesting.

-JS



From thelab at sprint.ca  Fri Jul 31 11:20:13 1998
From: thelab at sprint.ca (Philip)
Date: Fri, 31 Jul 1998 07:20:13 -0200
Subject: VCO idea
References: <199807310703.JAA28777@window.intermetall.de>
Message-ID: <35C18C4D.7CAE@sprint.ca>

Martin Czech wrote:

> I don't want to discourage you, but ... I toyed arround a lot with hand
> made waves and wavetables for the Waldorf Microwave I (No, I won't swap
> it against a Microwave II or XT) and came to the conclusion that in a
> lot of cases the results are not very exciting, certainly there are
> differences in sound, but I expected something to knock me off my
> chair, and this really happens, but not very often.

Original Idea:

> Why not have a repeating waveform that has (say) 4 "lines" of which the 
> slope and duration can be adjusted, either by a control knob or voltage 
> control.

I agree with Martin, spectral changes over time are needed to make
periodic waveforms sound interesting on their own, the VCO with the 4
variable sloped steps would sound much like playing single waves in a
Microwave. But by adding modulation control of the "slopes" and "steps"
of your design, it would sound far more interesting. AND it would
certainly sound more interesting than a simple sine, tri, sqr or ramp
osc so I feel it is interesting and worth persuing.

Maybe you could get hold of a MW or Nord Modular for experimentation? I
wrote a simple piece of software for the MWI that morphs two .wav files
(heck it will do any file too...ever hear autoexec.bat to config.sys :)
I find it very powerful even with no modulation routings other than the
wavetable morph from one .wav to the other. (VCF wide open). It is
really weird to hear such a variety of these nice sounds come from a MW
with no filter or modulations!! It is akin to additive synthesis where
filters are not really needed.

Anyway, a chain of cascading one shot ramps with polarity would do the
trick for the osc, I'm not sure of the details of scaling their time
constants via a CV however? Call its a "COS0" Cascaded One Shot
Oscillator :)

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 martin.czech at intermetall.de  Fri Jul 31 12:14:31 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 31 Jul 1998 12:14:31 +0200 (MET DST)
Subject: VCO idea
Message-ID: <199807311014.MAA29405@window.intermetall.de>

> 
> << toyed arround a lot with hand
>  made waves and wavetables for the Waldorf Microwave I (No, I won't swap
>  it against a Microwave II or XT) and came to the conclusion that in a
>  lot of cases the results are not very exciting, >>
> 
> Any static waveform, no matter how complex, will ultimately sound like an
> organ. It's animation and modulation that make them interesting. If the
> voltage controlled segment part of the original post was implemented it would
> probably be pretty cool but the basic ramp, triangle, sine and pulse pretty
> much cover all the bases otherwise. It's when you start changing these over
> time, either with filters or by modulating the pulse width for example, that
> things get interesting.
>
Good point, this is certainly true. Especially if the coefficients
change with fast, or maybe audio rate. By the way: you all know that
the  Waldorf Microwave is a wavetable synth, you can interpolate
between 61 different waves. It is a pain to draw all these variations
of waves but you can store them ... So there is some change, but still
the results where mostly disappointing (some where very good).  This
becomes very obvious if you want to process spech.  I've got a toy
sampler (Galactic Sampler for Atari ST/STE) with 8 bit resolution.  If
you record some vocals (a,e,i,o,u) you'll see that they are far away
from a periodic waveform.  There is a lot of modulation and randomness
in these waveforms. If you try a very short loop (force a periodic wave
out of it) from these waves, they are almost unrecognizeable, even if
you carefully avoid glitches.

So , sometimes even the change over time sound like organ, with some
kind of chorus or the like.  On the other hand, sometimes i got results
which sounded like ringmodulator stuff, with very odd nonperiodic
ratios. Now, this is not possible with such short 128 Byte waves, but
my ears don't know this fact ;-> I remember this was the case with
fourier synthesis, no fundamental and 17th .... 32th harmonic. Listen
to "chaos bells" in firmware version 2.0 of the Waldorf Microwave I.

By the way: the never changing, very simple, very precise waveforms are
one argument for electronic music. They are so different to natural
sound, like mathematical abstractions are to nature. And that's why I
like them. If one want's real strings, he should take a sampler.

m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style






From martin.czech at intermetall.de  Fri Jul 31 12:26:49 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 31 Jul 1998 12:26:49 +0200 (MET DST)
Subject: VCO idea
Message-ID: <199807311026.MAA29436@window.intermetall.de>

> 
> Anyway, a chain of cascading one shot ramps with polarity would do the
> trick for the osc, I'm not sure of the details of scaling their time
> constants via a CV however? Call its a "COS0" Cascaded One Shot
> Oscillator :)
> 
> Philip
> 
As you say, they have to track, this could turn out to be a lot of slave
vcos. By the way, how does a constant pulse-width pulse wave sound, if 
played over some octaves ?

Someone mentioned to use a analogue step sequencer as sound source.
This is a good idea, because each stage is independent from each other,
so it is relativley easy to understand and to handle.  The problem is
that the fundamental is N times lower then the vco, if the sequenzer
has N steps. Ok, a while ago I suggestet to use a saw wave and a set of
window-comparators for this purpose (a simple adc, if you like).  This
would avoide the frequency dividing. Someone said that these stepped
pulse waves sound too harsh, well one could use a tracking vcf lowpass
to kill the higher harmonics, a selectable slope 6,12,18,24 dB would be
a good feature for this purpose. Most filters have N equal stages,
simply use a 24dB filter and tap all stages, not only the last.

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 Juergen.Haible at nbgm.siemens.de  Fri Jul 31 12:52:35 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 31 Jul 1998 12:52:35 +0200
Subject: AW: VCO idea
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582900F7B@nbgm336a.nbgm.siemens.de>

	>What you are proposing is a "piecewise linear function" PLF, if I
got
	>it right.  A sawtooth wave is feed into some black box, and a PLF
comes
	>out.  This can be done using half wave precision rectifiers HWPR. 
[...]
	>If you want a non monotonic
	>PLF (like a triangle, first up, then downwards) this means the the
	>coefficient for the first breakpoint is 0.5, and for the next it
has to
	>be -1. Remember that both coefficient outputs are added together
[...]
>  And: every segment depends on all
	>predecessor segments. It's not like drawing the waveform with the
	>mouse.

You have to use full wave instead of half wave rectifiers.
Then the segments are independent, and you *can* draw 
the waveform (with a set of sliders, not with a mouse (;->) ).
No problems with nonmonotonic fuctions. No discontinuousities
(sp ??), though.,

Shameless self promotion: 
<http://www.synthfool.com/diy/jh_ipscan.html>

For PWL applications only, you can omit half of the circuit. No VCAs,
no VCA control path, put a slider potentiometer into each of the
LED driver paths, and sum all the slider output voltages together.

I'm planning to build such a version of the IS soon. A standalone box
without VCAs to act as variable "PWL" distortion device.

	>As I said, the nonmonotonic PLF are of most interest, because they
can
	>produce really strange harmonics. 

Right !

JH.






From chris at scp.de  Fri Jul 31 12:57:53 1998
From: chris at scp.de (Christian Hofmann)
Date: Fri, 31 Jul 1998 12:57:53 +0200
Subject: chorus pedal IC's
In-Reply-To: <199807310634.IAA28706@window.intermetall.de>
References: <199807310634.IAA28706@window.intermetall.de>
Message-ID: <199807311057.MAA31320@dilbert.scp.de>

On Fri, 31 Jul 1998 08:34:03 +0200 (MET DST)
Martin Czech <martin.czech at intermetall.de> wrote:

> RS Components have some MN300x BBDs, but not exactly the type you ask
> for. They have also a 3000 stage part, for arround 100 DM. Maybe you
> could contact the RS service and try to find the local panasonic
> distributor. I also tryed the panasonic/matsushita web page, no way.  I
> guess it's the same with Analog Devices. Some parts are still in
> production somehow, but the don't appear in datasheets or catalogues
> any more.

Hi,
does anyone know where those data sheets can be obtained? I found some
MNs at panasonic's site, but no BBDs.


Indeed, at least some MN type BBDs seem to be still in production, e.g.
the Boss CE-5 chorus pedal has a 3101 clock generator and 3007 BBD in it.
And I doubt all the other cheap analog fx units still being produced are
made from TDA1022s or SADs, so there must be some continuing source of
BBDs.

BTW, a few panasonic BBD chips are offered by some mail order dealers at
least here in germany. I would have to look that up though, if someone is
interested.

cu
Christian




From thelab at sprint.ca  Fri Jul 31 14:13:21 1998
From: thelab at sprint.ca (|[| Philip Pilgrim |]|)
Date: Fri, 31 Jul 1998 09:13:21 -0300
Subject: AW: VCO idea
References: <1BF5E20E0C4DD111BBAB00805FE2D582900F7B@nbgm336a.nbgm.siemens.de>
Message-ID: <35C1B4E1.66A1@sprint.ca>

Another implementation would be to have 1 OSC generate 4 or more
different waveforms. Then feed these into an analog multiplexer that
effectively switches it's output from one of the input waveform to the
other. Of course the switching signal source will have to also be from
the original osc. This design will remove the need to manage time
constants. For control parameters I would suggest switch timing, order
and Waveform dividing.

Some caps or comparitor logic for "smoothing" the transients would
complete the OSC. It is similar to what I saw on the Creamware SCOPE
platform except they called it a commuter.

Philip

-- 
Philip Pilgrim          	The Lab 
5 Evan's Drive          	- Analog/Digital Recording/Processing
Hammonds Plains       		- Computer/Synth Interfacing
Nova Scotia, Canada   		- Hardware/Software Development
B4B 1M8                   

   <<<<< Home of SH-101 NovaMod and UP Midi Programmer
>>>>>                     

Phone     +1.902.835.7844
Email     mailto:thelab at sprint.ca
Web Page: http://www.robotnik.com/the_lab/



From martin.czech at intermetall.de  Fri Jul 31 14:20:51 1998
From: martin.czech at intermetall.de (Martin Czech)
Date: Fri, 31 Jul 1998 14:20:51 +0200 (MET DST)
Subject: AW: VCO idea and env
Message-ID: <199807311220.OAA29946@window.intermetall.de>

> You have to use full wave instead of half wave rectifiers.
> Then the segments are independent, and you *can* draw 
> the waveform (with a set of sliders, not with a mouse (;->) ).
> No problems with nonmonotonic fuctions. No discontinuousities
> (sp ??), though.,
> 
> Shameless self promotion: 
> <http://www.synthfool.com/diy/jh_ipscan.html>
> 
> For PWL applications only, you can omit half of the circuit. No VCAs,
> no VCA control path, put a slider potentiometer into each of the
> LED driver paths, and sum all the slider output voltages together.
> 

Sorry Juergen, I have a hardcope of that circuit at home, totally forgotten.

Wow!

And now, as you say this, I see how a multi segment analogue envelope
generator could be done. We take a Haiblesian (sp?) interpolator, each
segment at a fixed position, so that neighbour channels meet at 50%,
and when one arrives at 100% the two neigbours must be at 0%.  The
input voltage for each segment is the breakpoint level, whereas the
scanning rate makes the breakpoint slope steepness (simply: the time).
And voila: time and level are perfectly decoupled! Something I gave up
to think about, cause I thaught this decoupling would be only possible
in the digital domain. The scanning waveform is a weird sawtooth, with
segments of different slope, but always rising. And even a constant
output feature is possible, no problems with too small charging
currents, the scanning waveform moves on, but the channel inputs are
the same, thus no output change.

I know, there was a thread about linear vs. exponential vs. log
envelopes.  I have the feeling, that this could be realised by the way
the scanning "sawtooth" is integrated, linear or exponential or log
(with saturation).  This feature could be switchable for every segment
individually.

One little comment I can't suppres: The above mentioned .html document
always says that triangle waves are used for scanning (am I right?).
But this means that every interpolator stage appears TWICE in one
cycle.  This is not quite what one expects, if you are going do "draw"
a PWL.  Instead a sawtooth wave should be used (what happens on the
"flyback" ?  glitches ?) I ask this not to annoy Juegen, but maybe I've
not understand the circuit.

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 JCM123 at webtv.net  Fri Jul 31 14:25:17 1998
From: JCM123 at webtv.net (John Mart)
Date: Fri, 31 Jul 1998 07:25:17 -0500 (CDT)
Subject: chorus pedal I.C.s
Message-ID: <28539-35C1B7AD-21@mailtod-112.iap.bryant.webtv.net>

There is a listing of  Panasonic MN3000 series BBD devices in the newest
Digi-Key catalog, including the 3009 and 3101 (page 181). These must be
the ones in question.  They also offer a booklet with data and circuits
for $3.50.  There's no minimum order, but you have to pay 5$ for orders
under 25$.  They're on the web,  I don't know about foreign orders.
There must be some way of getting that to you.  I have that  booklet.
Might be able to xerox the pages and send them through mail.
----John M.




From Juergen.Haible at nbgm.siemens.de  Fri Jul 31 15:01:33 1998
From: Juergen.Haible at nbgm.siemens.de (Haible Juergen)
Date: Fri, 31 Jul 1998 15:01:33 +0200
Subject: AW: AW: VCO idea and env
Message-ID: <1BF5E20E0C4DD111BBAB00805FE2D582904642@nbgm336a.nbgm.siemens.de>


	>One little comment I can't suppres: The above mentioned .html
document
	>always says that triangle waves are used for scanning (am I
right?).
	>But this means that every interpolator stage appears TWICE in one
	>cycle.  This is not quite what one expects, if you are going do
"draw"
	>a PWL.  Instead a sawtooth wave should be used (what happens on the
	>"flyback" ?  glitches ?) I ask this not to annoy Juegen, but maybe
I've
	>not understand the circuit.

Hmm, yes, if you have static waveforms and complete graphical 
control in mind, scanning with a saw wave is probably the best.
Just adjust the level of the saw input signal so that it comprises
exactly the full range from 1st to last slider. Glitches depend
on your saw reset time and input level / offset adjustment
in that case.
But as someone has mentioned, static waveforms are kind of
boring. The IS comes to full bloom with varying input levels
(or offsets etc.). I've made a lot of experiments since I built it,
and most rewarding setup is with the input signal running thru a VCA
(ADSR-controlled) before it goes into the IS. Even better, use an
external monosynth (or guitar, or anything else), which already has
a certain loudness contour. As for the waveform of the input signal,
low harmonic contents gives a more dramatical effect. That's why
I use triangles most of the time. But saw waves produce some nice 
effects, too.
For clean output waveforms, a 1 VCO source is fine. If you want the
IS to become alive, you may use a 2nd VCO or a LFO, either of which
would just be *added* to the main input signal. (No extra modulation
required here; just sum the two together.) Make sure that this second
source has a much lower level than the first one. A constant, low level
VCO2, and an ADSR-enveloped high level VCO1 is a good choice.
This is, for rather "tame" waveform sweeps. If you want to go wild,
feed a polyphonic synth into the IS. (A short VCA release time is a good
idea here ..) You might want to set a range of rather "weak" and monotonous
nonlinearity to process polyphonic sounds. Then add one "dent" (non
monotonous segments) at one end, and drive your polyphonic input source
into this region from time to time with a volume pedal etc.
Opps, it always becomes a long post when I write about the IS ... sorry.

BTW, the idea with the triagle input is inspired by the Hammond Scanner.
This one is rotating, i.e. start point and end point connected together, and
this would correspond to a saw modulation. BUT Hammond has wired the
scanner to get a symmetrical (sine ? triangle?) function nevertheless.
But this is for the other IS application, filter scanning, of course.
Just to explain the history of the idea ...

Even with other than saw input signals, a graphic slider repesentation
is still useful: In general, you don't draw the waveform, but the dc
transfer
function. So I wasn't exactly precise when I spoke of the forthcoming
distortion device. Graphically controlled nonlinear distortion courve
might fit.

In the ideal case, the PWL corners are quite sharp. The cubic spline
idea on my homepage was a joke, of course. But maybe the corners
should be rounded by using a less ideal rectifier. Something like the
MS-20 triangle converter comes to mind. But I haven't got a working
circuit for that version yet. Temperature compensation is important when
you go down near the threshold voltage of diodes ...

JH.




From 9705146x at lux.levels.unisa.edu.au  Fri Jul 31 16:32:43 1998
From: 9705146x at lux.levels.unisa.edu.au (9705146x)
Date: Sat, 1 Aug 1998 00:02:43 +0930 (CST)
Subject: VCO idea
Message-ID: <Pine.SOL.3.91.980801000011.8479A-100000@lux.levels.unisa.edu.au>

Thanks for all the input for my strange idea. InfoTech Mathematics was 
worth doing afterall, (so thats what piecewise linear models are used 
for :) ) It appears ive got you all thinking :) Not bad for some1 whos 
only just turned 20 :) BTW, am i the youngest on the diy list?

<bUd>



From amieuss at telcel.net.ve  Fri Jul 31 16:43:41 1998
From: amieuss at telcel.net.ve (Arturo Mieussens)
Date: Fri, 31 Jul 1998 10:43:41 -0400
Subject: chorus pedal I.C.s
Message-ID: <19980731144311.AAA26878@smarty.telcel.net.ve@telcel.telcel.net.ve>

Thanks to all of you at the list who helped me find the IC's, you are a
very nice crowd!

by the way, "ve" means Venezuela.

Have fun!

Arturo.



From b.layer at vikingelectronics.com  Fri Jul 31 17:58:10 1998
From: b.layer at vikingelectronics.com (Bill Layer)
Date: Fri, 31 Jul 1998 10:58:10 -0500
Subject: VCO idea
In-Reply-To: <Pine.SOL.3.91.980801000011.8479A-100000@lux.levels.unisa.e
 du.au>
Message-ID: <3.0.5.32.19980731105810.007a7d50@192.168.210.18>

 Not bad for some1 whos 
>only just turned 20 :) BTW, am i the youngest on the diy list?
 

Nope, I just turned six last week.


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

----------------------------------
Viking Electronics, Inc.
Hudson, WI. U.S.A
715.386.8861 (ext. 210)
<http://www.vikingelectronics.com>
----------------------------------

"Telecommunications Solutions for the 21st Century"



From jpc2125 at silver.sdsmt.edu  Fri Jul 31 19:14:09 1998
From: jpc2125 at silver.sdsmt.edu (Jay)
Date: Fri, 31 Jul 1998 12:14:09 -0500
Subject: VCO idea
References: <Pine.SOL.3.91.980801000011.8479A-100000@lux.levels.unisa.edu.au>
Message-ID: <35C1FB60.1CEBC55F@silver.sdsmt.edu>

I turned 20 on June 23rd.  Have I got you beat?

I better say something useful so I don't have to pick up the asbestos
shield.
I want to use my laptop computer as a midi sequencer, but it lacks a
gameport.  Does anybody know of a PCMCA card that does midi?

9705146x wrote:

> Thanks for all the input for my strange idea. InfoTech Mathematics was
> worth doing afterall, (so thats what piecewise linear models are used
> for :) ) It appears ive got you all thinking :) Not bad for some1 whos
> only just turned 20 :) BTW, am i the youngest on the diy list?
>
> <bUd>






From steve.ridley at bbc.co.uk  Fri Jul 31 19:22:49 1998
From: steve.ridley at bbc.co.uk (steve.ridley at bbc.co.uk)
Date: Fri, 31 Jul 1998 17:22:49 +0000
Subject: VCO idea
In-Reply-To: <09FF8E360103376C@c2-smtp.radio.bbc.co.uk>
Message-ID: <0DFF8E360103376C@c2-smtp.radio.bbc.co.uk>


I'm currently overhauling four Ken Gale "Wavemaker"
envelope generator modules, which do a similar sort
of thing - several voltage controlled slope stages
which can be looped to work as a sort of VCO.
The difficulty with using them as a VCO is that 
altering the settings of any of the slopes or 
end points will alter the tuning too, so shape
modulation and frequency modulation are tied
together. 
 
It should be possibel to lash up something 
similar with a VC slope module (Serge?) and a
two row sequencer.

STEVE RIDLEY




From mmcintos at ball.com  Fri Jul 31 21:27:40 1998
From: mmcintos at ball.com (McIntosh, Malcolm)
Date: Fri, 31 Jul 1998 13:27:40 -0600
Subject: Vacuum Tube Circuit Books
Message-ID: <09DB74475204D1119C8200805F19D0032D12A2@aeromsg1.ball.com>

I came across three interesting books which deal with Vacuum Tube
circuit designs.

"Vacuum-Tube Circuits and Transistors", by: Lawrence Baker Arguimbau and
Richard Brooks Adler (1956)
"Reference Data for Radio Engineers", published by: Federal Telephone
and Radio Corporation (1944)
"Pulse Techniques", by: Sidney Moskowitz and Joseph Racker (1951)

They seem to have some oscillator and amplifier circuits :-) but not
much on filtering :-(

Malcolm





From arnog at mygale.org  Fri Jul 31 23:22:24 1998
From: arnog at mygale.org (Arnaud GIRARD)
Date: Fri, 31 Jul 1998 15:22:24 -0600
Subject: Hi everyboday
Message-ID: <199807312121.PAA20144@fsa.enel.ucalgary.ca>

Today is an important day ..
Student engineer in electronics, 22 years old, I decided to start making my
own modular synth today, after 2 years of meditation ...
You guys know what you are talking about so is anyone king enough to advice
me on the best way to proceed and tell me where can I find the first
schematics i need for a small but complete modular ?

Bye 

Arno
FRANCE
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