From music.maker at gte.net  Tue Apr  1 00:07:25 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Mon, 31 Mar 2008 15:07:25 -0700
Subject: [sdiy] phLUTe
Message-ID: <200803312207.m2VM7PHU026873@linux7.lan>

Listen to the phLUTes play a Mozart string quartet.

http://www.fpga.synth.net/pmwiki/pmwiki.php?n=FPGASynth.PhLUTe

Sound links are down the page a bit.

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From samppa.tolvanen at gmail.com  Tue Apr  1 01:48:00 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 1 Apr 2008 02:48:00 +0300
Subject: [sdiy] Modern transistor matching
In-Reply-To: <009e01c89375$28f2b2f0$0400a8c0@jhsilent>
References: <200803192241.m2JMf33G010664@linux7.lan>
	<200803200424.m2K4OLuX024068@dropmix.xs4all.nl>
	<7.0.1.0.2.20080320025957.03ca21c0@sympatico.ca>
	<6.2.1.2.2.20080320073056.020c4788@mail.comcast.net>
	<7.0.1.0.2.20080320132117.044632e8@sympatico.ca>
	<EAEDD4D7-27FC-45D4-B2FE-DDDF706BADA6@asapnet.net>
	<004901c88b60$3e38f2e0$4589fe04@tim3>
	<009e01c89375$28f2b2f0$0400a8c0@jhsilent>
Message-ID: <fa1b0bd80803311648y219d65f7l4547789194613541@mail.gmail.com>

On 4/1/08, JH. <jhaible at debitel.net> wrote:

Ok,

hfe ~ 1mA might not tell Vbe ~1mA .. sorry, me stooid, You can alsways



cntCT
me samppatolvanen at hotmail.com


From dougt55 at yahoo.com  Tue Apr  1 05:32:32 2008
From: dougt55 at yahoo.com (Doug Terrebonne)
Date: Mon, 31 Mar 2008 20:32:32 -0700 (PDT)
Subject: [sdiy] Anyone know Rykhaard/Ryk Thekreator (Canadian sdiyer)?
In-Reply-To: <fa1b0bd80803311648y219d65f7l4547789194613541@mail.gmail.com>
Message-ID: <710193.94159.qm@web81207.mail.mud.yahoo.com>

Ryk promised to send me a synth back in 2006. After stringing it along
over and over he now won't respond to my emails.



From aankrom at bluemarble.net  Tue Apr  1 15:54:34 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 1 Apr 2008 09:54:34 -0400
Subject: [sdiy] Anyone make KLM-129 & other portions of Korg MS-20/MS10 etc.?
References: <200803312207.m2VM7PHU026873@linux7.lan>
Message-ID: <000001c89401$818e6490$0202a8c0@positronium>

I got the idea the other day to make the External Signal Processor (KLM-129) 
from the Korg MS-20 because I happened upon a GE "quad stereo" receiver that 
someone had thrown away. The outside was pretty well trashed and the circuit 
boards were littered with painted-on resistors where 1/4 resistors would 
be - and I just can't abide circuitry that I can't easilly modify. But the 
other parts were great: lots of epoxy sealed Sanyo electrolytic caps 
(although every now and then I entertain the possibility that these are 
tantalums but I really don't think so...), paint daubed 2SC693's, etc... But 
even better were the controls: yes the quad-panning joystick with 4 
individual 200kOhm pots that moved in pairs (this seems to make for a 
smoother action than some other joysticks I have even the one from the 
Panasonic "quad-stereo" receiver...); but the true gems were the 3 identical 
50kOhmAx4 slider pots. This is smaller than the 2 100kOhmCx4 on the KLM-129 
filter controls, but with a slider pot I don't have to worry about the 
reverse taper.

Korg circuits are some of my favorites and I follow avidly discussions about 
the filters. I'd really like to make a faithful copy of the original 
Sallen-Key version of the filter or whichever ones used that custom chip 
htat is impossible to find now.

It's too bad that these Korg synths weren't V/Oct. I guess the MS-02 makes 
that a moot point.

Now to find another use for that one remaining 50kx4 slider pot... 




From rtellason at verizon.net  Tue Apr  1 16:43:18 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Tue, 01 Apr 2008 10:43:18 -0400
Subject: [sdiy] What kind of synth is this?
Message-ID: <200804011043.18882.rtellason@verizon.net>

<http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/2070168575_d4efbbdc59_o.jpg>

?


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From steff at steff.name  Tue Apr  1 17:21:18 2008
From: steff at steff.name (Steffan Davies)
Date: Tue, 1 Apr 2008 15:21:18 +0000
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <200804011043.18882.rtellason@verizon.net>
References: <200804011043.18882.rtellason@verizon.net>
Message-ID: <20080401152117.GA27076@steff.name>

Roy J. Tellason <rtellason at verizon.net> wrote at 10:43 on 2008-04-01:

> <http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/2070168575_d4efbbdc59_o.jpg>
> 
> ?

Looking in the top left corner, there's a label which appears to read
"Damius". This led me to
http://www.toto99.com/features/encyclopedia/damius.shtml and hence to
http://www.synthmuseum.com/polyf/polyfusion01.html

S


From gabriel at lindeborg.org  Tue Apr  1 17:28:44 2008
From: gabriel at lindeborg.org (Gabriel Lindeborg)
Date: Tue, 01 Apr 2008 17:28:44 +0200
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <200804011043.18882.rtellason@verizon.net>
References: <200804011043.18882.rtellason@verizon.net>
Message-ID: <47F254AC.9070009@lindeborg.org>

It's called a modular synthesizer and consists of modules making up a 
complete synthesizer!

;-)

Looks kinda moogish, who's the fellow on the pic?

//Gabbe, sorry I could not resist that one...

Roy J. Tellason skrev:
> <http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/2070168575_d4efbbdc59_o.jpg>
>
> ?
>
>
>   


From jgrisso at det3.net  Tue Apr  1 17:31:58 2008
From: jgrisso at det3.net (Joe Grisso)
Date: Tue, 1 Apr 2008 09:31:58 -0600
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <GDEMKJDLKPDJFJGFBDFGEEBGDCAA.jays@aracnet.com>
References: <200804011043.18882.rtellason@verizon.net>
	<GDEMKJDLKPDJFJGFBDFGEEBGDCAA.jays@aracnet.com>
Message-ID: <864ec6740804010831m42813f31le7001a3ccdf8369c@mail.gmail.com>

If you look in the upper left-hand of the cap, it says "Damius" - It's
a polyfusion modular used to create most of the FM timbres on Toto's
"IV" album.

(shamelessly stolen from Toto's web site)

-Joe

On Tue, Apr 1, 2008 at 10:26 AM, Jay Schwichtenberg <jays at aracnet.com> wrote:
> Isn't that Jeff P., whats his name from Toto?
>
>  I thought that he used polyfusion but that looks more like a Moog.
>
>  Jay S.
>
>  -----Original Message-----
>  From: synth-diy-bounces at dropmix.xs4all.nl
>  [mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Roy J. Tellason
>  Sent: Tuesday, April 01, 2008 6:43 AM
>  To: synth-Diy diy
>  Subject: [sdiy] What kind of synth is this?
>
>
>  <http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/20701
>  68575_d4efbbdc59_o.jpg>
>
>  ?
>
>
>  --
>  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  ablest -- form of life in this section of space,  a critter that can
>  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  -
>  Information is more dangerous than cannon to a society ruled by
>  lies. --James
>  M Dakin
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>



-- 
Joe Grisso
Detachment 3 Engineering


From harrybissell at wowway.com  Tue Apr  1 17:39:51 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Tue, 1 Apr 2008 09:39:51 -0600
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <200804011043.18882.rtellason@verizon.net>
References: <200804011043.18882.rtellason@verizon.net>
Message-ID: <20080401153904.M33896@wowway.com>

(blonde mode on)

uhhh... is it a ... MODULAR ???   ;^P

</bmo>

H^) harry




On Tue, 01 Apr 2008 10:43:18 -0400, Roy J. Tellason wrote
>
<http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/2070168575_d4efbbdc59_o.jpg>
> 
> ?
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
> -
> Information is more dangerous than cannon to a society ruled by 
> lies. --James M Dakin
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From jdec at mindspring.com  Tue Apr  1 17:56:17 2008
From: jdec at mindspring.com (BrightBoy)
Date: Tue, 1 Apr 2008 11:56:17 -0400 (GMT-04:00)
Subject: [sdiy] What kind of synth is this?
Message-ID: <2465168.1207065377188.JavaMail.root@mswamui-andean.atl.sa.earthlink.net>

That is clearly a Polyfusion modular.

Cheers,

Jeff

-----Original Message-----
>From: Jay Schwichtenberg <jays at aracnet.com>
>Sent: Apr 1, 2008 12:26 PM
>To: "Roy J. Tellason" <rtellason at verizon.net>, synth-Diy diy <synth-diy at dropmix.xs4all.nl>
>Subject: RE: [sdiy] What kind of synth is this?
>
>Isn't that Jeff P., whats his name from Toto?
>
>I thought that he used polyfusion but that looks more like a Moog.
>
>Jay S.
>
>-----Original Message-----
>From: synth-diy-bounces at dropmix.xs4all.nl
>[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Roy J. Tellason
>Sent: Tuesday, April 01, 2008 6:43 AM
>To: synth-Diy diy
>Subject: [sdiy] What kind of synth is this?
>
>
><http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/20701
>68575_d4efbbdc59_o.jpg>
>
>?
>
>
>--
>Member of the toughest, meanest, deadliest, most unrelenting -- and
>ablest -- form of life in this section of space, ?a critter that can
>be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
>-
>Information is more dangerous than cannon to a society ruled by
>lies. --James
>M Dakin
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy






From jays at aracnet.com  Tue Apr  1 18:26:18 2008
From: jays at aracnet.com (Jay Schwichtenberg)
Date: Tue, 1 Apr 2008 08:26:18 -0800
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <200804011043.18882.rtellason@verizon.net>
Message-ID: <GDEMKJDLKPDJFJGFBDFGEEBGDCAA.jays@aracnet.com>

Isn't that Jeff P., whats his name from Toto?

I thought that he used polyfusion but that looks more like a Moog.

Jay S.

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Roy J. Tellason
Sent: Tuesday, April 01, 2008 6:43 AM
To: synth-Diy diy
Subject: [sdiy] What kind of synth is this?


<http://lh5.google.ca/abramsv/R-8VzPXRjMI/AAAAAAAANCE/jx8JYx24UY0/s800/20701
68575_d4efbbdc59_o.jpg>

?


--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by
lies. --James
M Dakin

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From julian at 22host24.com  Tue Apr  1 19:01:57 2008
From: julian at 22host24.com (Julian)
Date: Tue, 1 Apr 2008 18:01:57 +0100
Subject: [sdiy] adding more audio inputs to the ATMEL AT91SAM7SE processor
Message-ID: <00ed01c8941a$1a3cc570$0301a8c0@legba>

After all the talk of microprocessors recently, ive been looking more at the ATMEL AT91SAM7SE ARM unit, as it looks like it has a 
good ammount of fairly easily implamented I/O.

However, that said, i cant work out how easily to add more audio inputs.

Theres a paper ( http://www.atmel.com/dyn/resources/prod_documents/doc6020.pdf ) that shows connection of one or two of the SSC 
interfaces to an audio ADC, but the example is just dealing with two inputs (stereo) whilst, ideally, id like somthing to implament 
further inputs.

The datasheet for the device is availible from atmel (obviously) but theres a copy here too ( 
http://www.farnell.com/datasheets/102193.pdf )

The reason why im looking at the 7SE variant over the 7S is in the hopes of adding sample storage more easily.

As you may have guessed, im a novice at microprocessor implamentation, but im trying to make a start : )

Thanks, Julian



-- 
I am using the free version of SPAMfighter for private users.
It has removed 65706 spam emails to date.
Paying users do not have this message in their emails.
Get the free SPAMfighter here: http://www.spamfighter.com/len




From S.Jones at salford.ac.uk  Tue Apr  1 19:23:52 2008
From: S.Jones at salford.ac.uk (Steve Jones)
Date: Tue, 1 Apr 2008 18:23:52 +0100
Subject: [sdiy] Oberheim DMX drum machine start up problem
Message-ID: <C681271885727C4ABB4FB0377F93B166D4388F@ISD-EXV01.isdads.salford.ac.uk>

Hi,
I've had an Oberheim DX for a while and yesterday I bought a DMX - it was alright at the sellers house and again when I tried it later, but now it has a problem starting up. I searched online and found another person asking about the same problem exactly:
"...I have an Oberheim DMX that won't start. When I turn the thing on, there is a message on the LED screen that says * Oberheim DMX *. It won't do anything else though, non of the buttons will work except the quantize button. When I press it, it says "Data OK" and the machine makes a beep sound. - after this non of the buttons do anything, the machine is locked up.

My DMX has the memory expansion and rev 3.2 OS, no midi. Inside was what looked like a non standard battery, a VARTA MEMPAC 102, 4.8v 100 mAh, but I've changed this for a suitable 3.6v rechargable.

If I switch it on while holding erase, it beeps, displays "! MEMORY EMPTY !" followed by the same thing described above ie it still freezes.

Any suggestions how to get it going again?

Kind regards,
Steve Jones
Salford, UK.



From aankrom at bluemarble.net  Tue Apr  1 20:22:33 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 1 Apr 2008 14:22:33 -0400
Subject: [sdiy] What kind of synth is this?
References: <2465168.1207065377188.JavaMail.root@mswamui-andean.atl.sa.earthlink.net>
Message-ID: <002201c89425$5d197770$0202a8c0@positronium>

I have made or am in the middle of making, my share of Polyfusion circuits. 
All of them remain untested at the moment, but I have an enveope follower, 
the really cool & difficult to build quantizer completed. Halfway done are 
the noise source (I have so many of these, but none with an "infra-red" 
output...), divider and a modified version of the reverb module (since I 
have a reverb tank with a high impedence input). Seems like there's others I 
wanted to make too, but I forget where I put the schematics...

I usually do Korg or Buchla stuff in tiny bites along with Ray Wilson and 
Ken Stone circuits, but Polyfusion circuits are cool too, like Aries and Arp 
(can't wait to finish my 4072 VCF!).

Anthony 




From lists at studionebula.com  Tue Apr  1 22:24:08 2008
From: lists at studionebula.com (Adam Schabtach)
Date: Tue, 1 Apr 2008 14:24:08 -0600
Subject: [sdiy] What kind of synth is this?
In-Reply-To: <200804011043.18882.rtellason@verizon.net>
Message-ID: <005d01c89436$57419600$1102a8c0@Mariko>

That photo ran in Keyboard magazine, I think around 25 years ago. I was in
my teens and discovering synthesizers at the time. That photo just did me
in--the notion of a modular synth that huge gave me the worst case of
gear-lust. I never quite got over it, and some 20 years later I started
building a modular of my own. It's not as big as that one but it does the
job.

--Adam




From synth1 at airmail.net  Wed Apr  2 04:56:36 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Tue, 1 Apr 2008 21:56:36 -0500
Subject: [sdiy] SSM2040/SAD1024 FS
Message-ID: <01ac01c8946d$2ac0be80$b000a8c0@curley>

> Uncovered some NOS (not pulls!) of SSM2040 VCF IC (P5 Rev 2, Omega 8) and 
> the SAD1024 BBD delay IC.
>
> go to www.synthtech.com, click ORDER tab, look in upper left corner, click 
> CEM/SSM tag, parts are in the 'cart'.
>
> Paul S.
> 



From djservs at comcast.net  Wed Apr  2 05:27:57 2008
From: djservs at comcast.net (Nate Reeves)
Date: Tue, 1 Apr 2008 23:27:57 -0400
Subject: [sdiy] test
Message-ID: <03FD7DAD-F049-455B-84AE-AC3FC409061F@comcast.net>

test


From harrybissell at wowway.com  Wed Apr  2 20:55:37 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Wed, 2 Apr 2008 12:55:37 -0600
Subject: [sdiy] Frac Rack PCB sizes
In-Reply-To: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net>
References: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net>
Message-ID: <20080402185311.M45525@wowway.com>

Hello all

I'm windering if someone knows the PCB size that will fit
in a Frac-Rack, and if there are any fixed mounting hole locations.
I'm doing a PCB and I might want to fit it in this format... maybe some
extra PCBs will be available ?  No details because with a global
audience like this, you would be too expensive to kill afterwards :^P

H^) harry


Harry Bissell & Nora Abdullah 4eva



From jason at redfish.net  Wed Apr  2 21:02:08 2008
From: jason at redfish.net (Jason Proctor)
Date: Wed, 2 Apr 2008 12:02:08 -0700
Subject: [sdiy] Frac Rack PCB sizes
In-Reply-To: <20080402185311.M45525@wowway.com>
References: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net>
	<20080402185311.M45525@wowway.com>
Message-ID: <a06200704c419885d99c4@[10.0.1.201]>

i would have thought that some of the more complex Blacet ones like 
the Miniwave and Time Machine describe the upper limit of PCB size 
for Frac.

the Miniwave one is 6" x 4.5" or thereabouts.



>Hello all
>
>I'm windering if someone knows the PCB size that will fit
>in a Frac-Rack, and if there are any fixed mounting hole locations.
>I'm doing a PCB and I might want to fit it in this format... maybe some
>extra PCBs will be available ?  No details because with a global
>audience like this, you would be too expensive to kill afterwards :^P
>
>H^) harry
>
>
>Harry Bissell & Nora Abdullah 4eva
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From admin at bugbrand.co.uk  Wed Apr  2 21:20:40 2008
From: admin at bugbrand.co.uk (Tom Bugs)
Date: Wed, 02 Apr 2008 20:20:40 +0100
Subject: [sdiy] Frac Rack PCB sizes
In-Reply-To: <20080402185311.M45525@wowway.com>
References: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net>
	<20080402185311.M45525@wowway.com>
Message-ID: <47F3DC88.2010100@bugbrand.co.uk>

Hi Harry
Measuring one of the rack cases from Paia -- the vertical distance 
between mounting rails is 4.25" and the maximum depth into the case is 7".
Hope that helps!
Best, Tom

harrybissell at wowway.com wrote:
> Hello all
>
> I'm windering if someone knows the PCB size that will fit
> in a Frac-Rack, and if there are any fixed mounting hole locations.
> I'm doing a PCB and I might want to fit it in this format... maybe some
> extra PCBs will be available ?  No details because with a global
> audience like this, you would be too expensive to kill afterwards :^P
>
> H^) harry
>
>
> Harry Bissell & Nora Abdullah 4eva
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>   



From neil.johnson97 at ntlworld.com  Wed Apr  2 21:30:42 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 2 Apr 2008 20:30:42 +0100
Subject: [sdiy] Synth DIY UK 2008 - A Reminder
Message-ID: <45AC2A00-7157-4F33-A719-8771F73093E0@ntlworld.com>

Hi all,

Just a quick reminder about this year's synth-diy meeting here in  
sunny Cambridge.

What : synths, synths, beer, synths
When : 11th - 13th July 2008
Where: Robinson College, Cambridge <http://www.robinson.cam.ac.uk/ 
contact/directions.php>

To book a room for the weekend please do so by filling out the form  
below:

	http://www.njohnson.co.uk/SDIY/roombooking.html

And photos from previous years are here:

	http://www.diy.synth.net/uk

This event is open to anyone.  Day trippers are most welcome, so if  
you hate the thought of sleeping in a student room (they are _nice_  
student rooms!), or you live locally, come on over and join in the fun.

Cheers,
Neil
--
http://www.njohnson.co.uk





From resonant at hoohahrecords.com  Wed Apr  2 21:35:13 2008
From: resonant at hoohahrecords.com (Dave Magnuson)
Date: Wed, 2 Apr 2008 15:35:13 -0400
Subject: [sdiy] Frac Rack PCB sizes
References: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net>
	<20080402185311.M45525@wowway.com>
Message-ID: <003901c894f8$ac733210$6501a8c0@HypoLuxa>

Hi Harry;

I have both Paia and Blacet racks here, and took a few dimensions.   These 
are essentially maximum PCB sizes:

Paia cabinet:
- Space between top / bottom rail: 4.625"
- Cabinet depth:  7.00"

Blacet cabinet:
-Space between top / bottom rail: 4.125"
-cabinet depth: 6.875"

In either case, you'd be nearly touching the rails / back panel with the 
above dimensions - so you'll want to subtract for desired clearance.

I'm not sure if there are "standard" mounting holes:   All of the blacet 
modules that I own are mounted by the nuts on the pots.   And I only have 1 
Paia module, so I'd hesistate to make assumptions on their mounting holes

If it were me, I'd design for the Blacet standards - and then your PCB will 
fit in either case design.

Dave Magnuson

----- Original Message ----- 
From: <harrybissell at wowway.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 02, 2008 2:55 PM
Subject: [sdiy] Frac Rack PCB sizes


> Hello all
>
> I'm windering if someone knows the PCB size that will fit
> in a Frac-Rack, and if there are any fixed mounting hole locations.
> I'm doing a PCB and I might want to fit it in this format... maybe some
> extra PCBs will be available ?  No details because with a global
> audience like this, you would be too expensive to kill afterwards :^P
>
> H^) harry
>
>
> Harry Bissell & Nora Abdullah 4eva
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From jason at redfish.net  Wed Apr  2 21:37:43 2008
From: jason at redfish.net (Jason Proctor)
Date: Wed, 2 Apr 2008 12:37:43 -0700
Subject: [sdiy] Synth DIY UK 2008 - A Reminder
In-Reply-To: <45AC2A00-7157-4F33-A719-8771F73093E0@ntlworld.com>
References: <45AC2A00-7157-4F33-A719-8771F73093E0@ntlworld.com>
Message-ID: <a06200709c41990f09c57@[10.0.1.201]>

>What: synths, synths, BEER, synths

eeeh, i miss the UK sometimes



From resonant at hoohahrecords.com  Wed Apr  2 21:38:11 2008
From: resonant at hoohahrecords.com (Dave Magnuson)
Date: Wed, 2 Apr 2008 15:38:11 -0400
Subject: [sdiy] Frac Rack PCB sizes
References: <C5B090F7-58AA-4FD1-9AFA-FA277D898F18@electricdruid.net><20080402185311.M45525@wowway.com>
	<47F3DC88.2010100@bugbrand.co.uk>
Message-ID: <004e01c894f9$167b3540$6501a8c0@HypoLuxa>

I noticed I made a mistake:

Tom is correct:  Paia is 4.25 clear inside - not the 4.625 I mentioned in my 
previous reply

Dave Magnuson

----- Original Message ----- 
From: "Tom Bugs" <admin at bugbrand.co.uk>
To: <harrybissell at wowway.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 02, 2008 3:20 PM
Subject: Re: [sdiy] Frac Rack PCB sizes


> Hi Harry
> Measuring one of the rack cases from Paia -- the vertical distance between 
> mounting rails is 4.25" and the maximum depth into the case is 7".
> Hope that helps!
> Best, Tom
>
> harrybissell at wowway.com wrote:
>> Hello all
>>
>> I'm windering if someone knows the PCB size that will fit
>> in a Frac-Rack, and if there are any fixed mounting hole locations.
>> I'm doing a PCB and I might want to fit it in this format... maybe some
>> extra PCBs will be available ?  No details because with a global
>> audience like this, you would be too expensive to kill afterwards :^P
>>
>> H^) harry
>>
>>
>> Harry Bissell & Nora Abdullah 4eva
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From neil.johnson97 at ntlworld.com  Wed Apr  2 21:44:47 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 2 Apr 2008 20:44:47 +0100
Subject: [sdiy] Low cost PCB house
Message-ID: <F3940CB3-1AC8-46BD-9C7F-35D92AC8448D@ntlworld.com>

Hi all,

You may have noticed a number of Chinese PCB fabs appearing on eBay.   
I did, and decided to give one a go.  This one in fact:

	http://stores.ebay.co.uk/E-Lab-UK

(their "Low Cost 1-2 Layer PCB Manufacture Service").

Based on a run of 10 boards 2" x 3" (approx), double sided with  
solder mask and silkscreen I think I will be using them again.  Ok,  
the boards are not *perfect* (there is a slight misalignment in the  
soldermask - but you can only see it under a microscope) but they are  
perfect enough for through-hole, and most likely surface mount too.

The price, including delivery (they came by DHL), for the quality is  
bloody amazing.  For less than 200 sq.in the price is ?35 + 18p per  
sq.in.

I'll bring one along to this year's synth diy in case anyone is  
interested.

Oh, and they sent me 12 boards instead of the 10 I ordered  
(overrun).  Which was nice.

Cheers,
Neil
--
http://www.njohnson.co.uk






From grichter at asapnet.net  Wed Apr  2 22:08:10 2008
From: grichter at asapnet.net (Grant Richter)
Date: Wed, 2 Apr 2008 15:08:10 -0500
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
In-Reply-To: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
References: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
Message-ID: <AE65AA0D-AD05-4D78-BEE6-6F68AE6408C5@asapnet.net>

Put the LED in the feedback loop of an op-amp. Makes it linear.

On Apr 2, 2008, at 3:38 PM, Justin Owen wrote:

> Hello,
>
> Thought I'd post this here because I know a few of you use LDRs/ 
> Vactrols in your projects.
>
> I've been using the H11F3 optocoupler as a modulation destination/ 
> controller. Very cool little IC - but I've still got the age old  
> problem that controlling the brightness of the internal LED with a  
> regular pot gives me a very uneven taper. i.e. approximately 90% of  
> the taper gives a very small increase in brightness and the last  
> 10% or so jumps right up - which doesn't make for a very even  
> control curve.
>
> I know the standard way of improving this is to use PWM to control  
> the brightness - and the couple of circuits I've tried have  
> definitely been an improvement...
>
> ...but - I was wondering if there was simpler way - somewhere  
> between just a pot and a full-blown PWM circuit? (On this project  
> I've got the equivalent of 11 LEDs to control - so that's a lot of  
> extra components).
>
> I was sure I saw something about adjusting the taper of a pot  
> somewhere - but for the life of me a I can't find it now.
>
> Any clues would be most appreciated.
>
> Thanks much - J
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From harrybissell at wowway.com  Wed Apr  2 22:10:21 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Wed, 2 Apr 2008 14:10:21 -0600
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
In-Reply-To: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
References: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
Message-ID: <20080402200903.M70723@wowway.com>

You can put the LED in the feedback loop of an opamp
(inverting) and drive it with current.  Set the input
resistor for the current you want per volt, for instance

H^) harry



On Wed, 2 Apr 2008 20:38:33 +0000, Justin Owen wrote
> Hello,
> 
> Thought I'd post this here because I know a few of you use 
> LDRs/Vactrols in your projects.
> 
> I've been using the H11F3 optocoupler as a modulation 
> destination/controller. Very cool little IC - but I've still got the 
> age old problem that controlling the brightness of the internal LED 
> with a regular pot gives me a very uneven taper. i.e. approximately 
> 90% of the taper gives a very small increase in brightness and the 
> last 10% or so jumps right up - which doesn't make for a very even 
> control curve.
> 
> I know the standard way of improving this is to use PWM to control 
> the brightness - and the couple of circuits I've tried have 
> definitely been an improvement...
> 
> ...but - I was wondering if there was simpler way - somewhere 
> between just a pot and a full-blown PWM circuit? (On this project 
> I've got the equivalent of 11 LEDs to control - so that's a lot of 
> extra components).
> 
> I was sure I saw something about adjusting the taper of a pot 
> somewhere - but for the life of me a I can't find it now.
> 
> Any clues would be most appreciated.
> 
> Thanks much - J
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From juzowen at googlemail.com  Wed Apr  2 22:38:33 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Wed, 2 Apr 2008 20:38:33 +0000
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
Message-ID: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>

Hello,

Thought I'd post this here because I know a few of you use LDRs/Vactrols in your projects.

I've been using the H11F3 optocoupler as a modulation destination/controller. Very cool little IC - but I've still got the age old problem that controlling the brightness of the internal LED with a regular pot gives me a very uneven taper. i.e. approximately 90% of the taper gives a very small increase in brightness and the last 10% or so jumps right up - which doesn't make for a very even control curve.

I know the standard way of improving this is to use PWM to control the brightness - and the couple of circuits I've tried have definitely been an improvement...

...but - I was wondering if there was simpler way - somewhere between just a pot and a full-blown PWM circuit? (On this project I've got the equivalent of 11 LEDs to control - so that's a lot of extra components).

I was sure I saw something about adjusting the taper of a pot somewhere - but for the life of me a I can't find it now.

Any clues would be most appreciated.

Thanks much - J




From synth1 at airmail.net  Thu Apr  3 02:07:25 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Wed, 2 Apr 2008 19:07:25 -0500
Subject: [sdiy] New R. Rich MOTM CD/website
Message-ID: <008101c8951e$b28a6170$b000a8c0@curley>

> www.robertrich.com new website, lots of analog synth audio tracks
>
> New live recording "React" featuring Ian Boddy (UK DiN Records). MOTM 
> analog modular featured.
>
> Paul S.
>
> 



From aym-htnys at teaser.fr  Thu Apr  3 02:44:06 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Thu, 3 Apr 2008 02:44:06 +0200
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
In-Reply-To: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
References: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
Message-ID: <20080403004406.GA31723@aym.net2.nerim.net>

On 2008-04-02 20:38 +0000, Justin Owen wrote:

> I was sure I saw something about adjusting the taper of a pot
> somewhere - but for the life of me a I can't find it now.

http://www.elby-designs.com/documents/tailoringpotentionometers.pdf
http://www.geofex.com/Article_Folders/potsecrets/potscret.htm

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From electronicpresskit at gmail.com  Thu Apr  3 10:11:14 2008
From: electronicpresskit at gmail.com (epk)
Date: Thu, 3 Apr 2008 01:11:14 -0700
Subject: [sdiy] one step 909
Message-ID: <44CB3074-9494-459E-B4E6-ED25DF86FA93@gmail.com>

Hey all,

just swapped out a cpu in a TR-909 and it seems like that fixed a lot  
of problems, however all patterns are only one step long and I can't  
seem to change how many steps there are.  I tried resetting the ram  
but no luck.  Does this sound like a bad ram chip?

Thanks,

epk


From electronicpresskit at gmail.com  Thu Apr  3 13:43:14 2008
From: electronicpresskit at gmail.com (epk)
Date: Thu, 3 Apr 2008 04:43:14 -0700
Subject: [sdiy] one step 909
In-Reply-To: <003e01c89571$555b0290$0301a8c0@legba>
References: <44CB3074-9494-459E-B4E6-ED25DF86FA93@gmail.com>
	<003e01c89571$555b0290$0301a8c0@legba>
Message-ID: <55670B31-B396-47C5-84FF-5919C5A0100E@gmail.com>

based on the 909 manual I should be able to adjust the number of  
steps by holding down the "last step" and hitting a main key and  
doing this doesn't work.  Also tried while holding down shift just in  
case but still no luck.

I've never actually programmed a 909 before and am going just based  
on the manual, so user error suggestions are certainly welcomed!

Thanks!

epk

On Apr 3, 2008, at 2:58 AM, Julian wrote:

> I know youve probably done somthing similar, but 606s can get stuck  
> like this, and its a natural procedure to get back the other 16  
> steps...
>
> On the 606 you have to hold function, and hit the last step button.
>
> Now i know youve probably done whatever needs to be done on the  
> 909, but i thought it was worth mentioning 'just in case' you hadnt...
>
> Julian
>
>
> ----- Original Message ----- From: "epk"  
> <electronicpresskit at gmail.com>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Thursday, April 03, 2008 9:11 AM
> Subject: [sdiy] one step 909
>
>
>> Hey all,
>>
>> just swapped out a cpu in a TR-909 and it seems like that fixed a  
>> lot  of problems, however all patterns are only one step long and  
>> I can't  seem to change how many steps there are.  I tried  
>> resetting the ram  but no luck.  Does this sound like a bad ram chip?
>>
>> Thanks,
>>
>> epk
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
> -- 
> I am using the free version of SPAMfighter for private users.
> It has removed 66543 spam emails to date.
> Paying users do not have this message in their emails.
> Get the free SPAMfighter here: http://www.spamfighter.com/len
>
>



From julian at 22host24.com  Thu Apr  3 21:02:36 2008
From: julian at 22host24.com (Julian)
Date: Thu, 3 Apr 2008 20:02:36 +0100
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
References: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
	<AE65AA0D-AD05-4D78-BEE6-6F68AE6408C5@asapnet.net>
Message-ID: <00d301c895bd$4a5d1170$0301a8c0@legba>



> Put the LED in the feedback loop of an op-amp. Makes it linear.


Ive been thinking of using vactrols to control some things, and Grant / Harry have just demonstrated how to get a controlled linear 
response, but what about a controlled antilog response, and a controlled log response?

Basically i want to use the same value control pot for every vactrol, and have some varying logarithmically between value a and 
value b, and some varying with a linear response from b to a, some from c to d etc.etc.  I want lots of different resistances and 
'tapers' from the same input.

In truth, i havent really thought about this very far, but its the antilog that seems the problem...


Julian 


-- 
I am using the free version of SPAMfighter for private users.
It has removed 66543 spam emails to date.
Paying users do not have this message in their emails.
Get the free SPAMfighter here: http://www.spamfighter.com/len




From juzowen at googlemail.com  Thu Apr  3 21:49:23 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Thu, 3 Apr 2008 19:49:23 +0000
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
Message-ID: <47f526b6.1ade660a.7a39.ffffa857@mx.google.com>

Thanks to everyone that helped out on this - the op-amp solution is perfect.

Appreciated.

J

-----Original Message-----
From: Grant Richter [grichter at asapnet.net]
Received: 02.04.2008 20:08:20
To: Justin Owen
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer

Put the LED in the feedback loop of an op-amp. Makes it linear.

On Apr 2, 2008, at 3:38 PM, Justin Owen wrote:

> Hello,
>
> Thought I'd post this here because I know a few of you use LDRs/ 
> Vactrols in your projects.
>
> I've been using the H11F3 optocoupler as a modulation destination/ 
> controller. Very cool little IC - but I've still got the age old  
> problem that controlling the brightness of the internal LED with a  
> regular pot gives me a very uneven taper. i.e. approximately 90% of  
> the taper gives a very small increase in brightness and the last  
> 10% or so jumps right up - which doesn't make for a very even  
> control curve.
>
> I know the standard way of improving this is to use PWM to control  
> the brightness - and the couple of circuits I've tried have  
> definitely been an improvement...
>
> ...but - I was wondering if there was simpler way - somewhere  
> between just a pot and a full-blown PWM circuit? (On this project  
> I've got the equivalent of 11 LEDs to control - so that's a lot of  
> extra components).
>
> I was sure I saw something about adjusting the taper of a pot  
> somewhere - but for the life of me a I can't find it now.
>
> Any clues would be most appreciated.
>
> Thanks much - J
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy






From tsheets at saturn5.com  Fri Apr  4 01:36:44 2008
From: tsheets at saturn5.com (tsheets at saturn5.com)
Date: Thu, 3 Apr 2008 16:36:44 -0700
Subject: [thomas@thomaslaskowski.com: [sdiy] FS: possible ASM-1 for sale]
Message-ID: <20080403233644.GA6129@atari.saturn5.com>



Hi, I paypal-ed Thomas $350 for this ASM-1 exactly 4 weeks ago today,
and I still don't have a tracking number, and the last email I got from him
was about 2 weeks ago.  I would warn anyone against future purchases from him.

If the situation changes, I will happily notify this list.

-troy


----- Forwarded message from Thomas Laskowski <thomas at thomaslaskowski.com> -----


Hi guys,

I used to be a member while I was at university.  That was several years 
ago.  I have a pretty much fully assembled ASM-1 with front panel, patch 
cables (stackable banana plugs), and all.  You can look at the pictures 
here (some of those are outdated) 
http://www.thomaslaskowski.com/asm1/ASM-1.html
I can take more pictures.
I believe that all the wiring to the panel is complete and I have done 
some testing.  I also have a power supply that I can throw in.  But no 
MIDI-CV converter sorry.

If anyone is interested please make me an offer.  It's been sitting in 
the basement for a few years now without any use.  I believe that 
someone could find a use for it.

I can retest it again because it hasn't been used in a long time.  But 
it's guaranteed to work.

Sorry to barge in like this, but I need to do some clean up.

Cheers,

-Tom

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

----- End forwarded message -----

-- 
------------------------------------------------------------------------------
tsheets at saturn5.com                                  <- You have found me   
http://www.ferrapsylix.com                           <- sub atomic breakbeat
"I just don't have the discipline to be a hippie"    <- Homer J. Simpson


From ebrombaugh at earthlink.net  Fri Apr  4 03:41:50 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Thu, 03 Apr 2008 18:41:50 -0700
Subject: [sdiy] adding more audio inputs to the ATMEL AT91SAM7SE processor
In-Reply-To: <00ed01c8941a$1a3cc570$0301a8c0@legba>
References: <00ed01c8941a$1a3cc570$0301a8c0@legba>
Message-ID: <47F5875E.8050007@earthlink.net>

Julian wrote:
> After all the talk of microprocessors recently, ive been looking more at 
> the ATMEL AT91SAM7SE ARM unit, as it looks like it has a good ammount of 
> fairly easily implamented I/O.
> 
> However, that said, i cant work out how easily to add more audio inputs.
> 
> Theres a paper ( 
> http://www.atmel.com/dyn/resources/prod_documents/doc6020.pdf ) that 
> shows connection of one or two of the SSC interfaces to an audio ADC, 
> but the example is just dealing with two inputs (stereo) whilst, 
> ideally, id like somthing to implament further inputs.
> 
> The datasheet for the device is availible from atmel (obviously) but 
> theres a copy here too ( http://www.farnell.com/datasheets/102193.pdf )
> 
> The reason why im looking at the 7SE variant over the 7S is in the hopes 
> of adding sample storage more easily.
> 
> As you may have guessed, im a novice at microprocessor implamentation, 
> but im trying to make a start : )

Yes - the Atmel SAM7 parts are fairly attractive MCUs. They've got some 
useful peripherals, a fair amount of I/O and are amazingly inexpensive. 
Digital Audio is handled via the SCC (synchronous communications 
controller) which can be configured for a variety of different serial 
audio protocols and has both input and output capability.

Adding more audio I/O will be a challenge though: The SCC is really only 
designed to handle a single I2S codec, which means you get two channels 
of input and two channels of output. To add more channels of I2S I/O 
you'll have to start hacking on your own hardware - either some kind of 
kludge to mux the single SCC port signals, or a complete separate 
interface. Neither of these is particularly attractive unless you have 
access to CPLDs and/or FPGAs.

A few other things to note:

- The SE parts are distinguished by having external memory access ports. 
This means they have a lot more I/O pins than the S parts which are 
completely self-contained. To handle all this I/O, they come in 128-pin 
LQFP and 144-ball BGA packages. I haven't done a search online to see if 
there are pre-built development boards available for these parts, but if 
not you may find this type of hardware construction to be a big 
challenge to take on.

- The external memory bus interface shares pins with GPIO and other 
peripherals. If you want to use external memory you'll find that the SCC 
I/O pins conflict with some of the address and chip select pins and will 
constrain the amount of external memory you can access.

If you're just interested in some fundamental concepts of 
microcontrollers and audio then the SAM7SE or SAM7S parts may be ideal 
places to start. If you have definite requirements for more than 2 
channels of processing and large external memories then you might want 
to consider looking at other architectures.

Eric


From S.Jones at salford.ac.uk  Fri Apr  4 12:05:58 2008
From: S.Jones at salford.ac.uk (Steve Jones)
Date: Fri, 4 Apr 2008 11:05:58 +0100
Subject: [sdiy] one step 909
References: <44CB3074-9494-459E-B4E6-ED25DF86FA93@gmail.com><003e01c89571$555b0290$0301a8c0@legba>
	<55670B31-B396-47C5-84FF-5919C5A0100E@gmail.com>
Message-ID: <C681271885727C4ABB4FB0377F93B166D43890@ISD-EXV01.isdads.salford.ac.uk>

"I should be able to adjust the number of  
steps by holding down the "last step" and hitting a main key and  
doing this doesn't work"

For this to work you do need to be in pattern write mode. Shift + pattern button (1, 2, or 3) (pattern button will flash to indicate pattern write mode) then select the pattern (1 - 16 main key) that you want to edit. Then hit play, then do the last step procedure.

Steve Jones


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl on behalf of epk
Sent: Thu 03/04/2008 12:43
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] one step 909
 
based on the 909 manual I should be able to adjust the number of  
steps by holding down the "last step" and hitting a main key and  
doing this doesn't work.  Also tried while holding down shift just in  
case but still no luck.

I've never actually programmed a 909 before and am going just based  
on the manual, so user error suggestions are certainly welcomed!

Thanks!

epk

On Apr 3, 2008, at 2:58 AM, Julian wrote:

> I know youve probably done somthing similar, but 606s can get stuck  
> like this, and its a natural procedure to get back the other 16  
> steps...
>
> On the 606 you have to hold function, and hit the last step button.
>
> Now i know youve probably done whatever needs to be done on the  
> 909, but i thought it was worth mentioning 'just in case' you hadnt...
>
> Julian
>
>
> ----- Original Message ----- From: "epk"  
> <electronicpresskit at gmail.com>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Thursday, April 03, 2008 9:11 AM
> Subject: [sdiy] one step 909
>
>
>> Hey all,
>>
>> just swapped out a cpu in a TR-909 and it seems like that fixed a  
>> lot  of problems, however all patterns are only one step long and  
>> I can't  seem to change how many steps there are.  I tried  
>> resetting the ram  but no luck.  Does this sound like a bad ram chip?
>>
>> Thanks,
>>
>> epk
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
> -- 
> I am using the free version of SPAMfighter for private users.
> It has removed 66543 spam emails to date.
> Paying users do not have this message in their emails.
> Get the free SPAMfighter here: http://www.spamfighter.com/len
>
>

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy





From harrybissell at wowway.com  Fri Apr  4 14:49:56 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Fri, 4 Apr 2008 06:49:56 -0600
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
In-Reply-To: <00d301c895bd$4a5d1170$0301a8c0@legba>
References: <47f3e0bf.10094e0a.1c00.1852@mx.google.com>
	<AE65AA0D-AD05-4D78-BEE6-6F68AE6408C5@asapnet.net>
	<00d301c895bd$4a5d1170$0301a8c0@legba>
Message-ID: <20080404124848.M76471@wowway.com>

Once you have linear control (opamp feedback) you can add
expo, or log circuits before that stage to drive it.

You would ideally want an opamp per LED anyway. If you have only 
a couple of LEDs they couls be in series...

H^) harry




On Thu, 3 Apr 2008 20:02:36 +0100, Julian wrote
> > Put the LED in the feedback loop of an op-amp. Makes it linear.
> 
> Ive been thinking of using vactrols to control some things, and 
> Grant / Harry have just demonstrated how to get a controlled linear 
> response, but what about a controlled antilog response, and a 
> controlled log response?
> 
> Basically i want to use the same value control pot for every vactrol,
>  and have some varying logarithmically between value a and value b,
>  and some varying with a linear response from b to a, some from c to 
> d etc.etc.  I want lots of different resistances and 'tapers' from 
> the same input.
> 
> In truth, i havent really thought about this very far, but its the 
> antilog that seems the problem...
> 
> Julian
> 
> -- 
> I am using the free version of SPAMfighter for private users.
> It has removed 66543 spam emails to date.
> Paying users do not have this message in their emails.
> Get the free SPAMfighter here: http://www.spamfighter.com/len


Harry Bissell & Nora Abdullah 4eva



From alfred.pear at gmail.com  Fri Apr  4 20:21:34 2008
From: alfred.pear at gmail.com (alfred.pear at gmail.com)
Date: Fri, 4 Apr 2008 14:21:34 -0400
Subject: [sdiy] Mixer Design Question
Message-ID: <ea992b2f0804041121r1d64bbafs3d7cb77f60c9dc8a@mail.gmail.com>

Hi -

I'm relatively new to electronics building and op amps have been
keeping me suitably occupied.
However, I have a particular application and I can't quite wrap my
head around the circuit design and was hoping someone would be kind
enough to help me.

Essentially, I'd like six independent channels to use as discrete
pre-amps, but I would also like the option of patching them into a
single, final stage with an overall gain control.

Is there a design where I can maintain the integrity of the singular
pre-amps, while having an overall final mix in a separate output?

Since I'm not totally at home with diodes yet, if they are necessary,
is there a way to do this while maintaining both polarities in the
final stage?

Thanks to all,
Al


From aaron at receive-transmit.com  Fri Apr  4 20:50:56 2008
From: aaron at receive-transmit.com (Aaron Day)
Date: Fri, 4 Apr 2008 20:50:56 +0200
Subject: [sdiy] test ignore
Message-ID: <0963D3BC-851D-4670-8D1D-85AB7E07195A@receive-transmit.com>

please stop bouncing



From juzowen at googlemail.com  Fri Apr  4 20:52:54 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Fri, 4 Apr 2008 18:52:54 +0000
Subject: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer
Message-ID: <47f66af9.1c185e0a.796d.ffff96c5@mx.google.com>

One of the links that Andre M was kind enough to post is a very good discussion on messing with the taper of pots:

http://www.elby-designs.com/documents/tailoringpotentionometers.pdf

J

-----Original Message-----
From: Julian [julian at 22host24.com]
Received: 03.04.2008 19:02:43
To: Grant Richter; Justin Owen; harrybissell at wowway.com
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] A simpler LED/Optocoupler/Vactrol dimmer



> Put the LED in the feedback loop of an op-amp. Makes it linear.


Ive been thinking of using vactrols to control some things, and Grant / Harry have just demonstrated how to get a controlled linear 
response, but what about a controlled antilog response, and a controlled log response?

Basically i want to use the same value control pot for every vactrol, and have some varying logarithmically between value a and 
value b, and some varying with a linear response from b to a, some from c to d etc.etc.  I want lots of different resistances and 
'tapers' from the same input.

In truth, i havent really thought about this very far, but its the antilog that seems the problem...


Julian 


-- 
I am using the free version of SPAMfighter for private users.
It has removed 66543 spam emails to date.
Paying users do not have this message in their emails.
Get the free SPAMfighter here: http://www.spamfighter.com/len







From harrybissell at wowway.com  Fri Apr  4 21:38:22 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Fri, 4 Apr 2008 13:38:22 -0600
Subject: [sdiy] Mixer Design Question
In-Reply-To: <ea992b2f0804041121r1d64bbafs3d7cb77f60c9dc8a@mail.gmail.com>
References: <ea992b2f0804041121r1d64bbafs3d7cb77f60c9dc8a@mail.gmail.com>
Message-ID: <20080404193505.M14118@wowway.com>

I think you might want to use an Inverting Summing Amplifier
(opamp circuit) to add the six preamps. You could have output
jacks that are "normallized" so that if you do not use an individual
output(s) they will be automatically patched throuh the mixer.

If you don't want the singal inverted, you could use a second
inverting opamp, with the volume control inbetween the summer
(mixer) and the output. This would be a really good way to go as the pot
would be buffered by the second opamp.

H^) harry



On Fri, 4 Apr 2008 14:21:34 -0400, alfred.pear wrote
> Hi -
> 
> I'm relatively new to electronics building and op amps have been
> keeping me suitably occupied.
> However, I have a particular application and I can't quite wrap my
> head around the circuit design and was hoping someone would be kind
> enough to help me.
> 
> Essentially, I'd like six independent channels to use as discrete
> pre-amps, but I would also like the option of patching them into a
> single, final stage with an overall gain control.
> 
> Is there a design where I can maintain the integrity of the singular
> pre-amps, while having an overall final mix in a separate output?
> 
> Since I'm not totally at home with diodes yet, if they are necessary,
> is there a way to do this while maintaining both polarities in the
> final stage?
> 
> Thanks to all,
> Al
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From jhaible at debitel.net  Fri Apr  4 23:03:47 2008
From: jhaible at debitel.net (JH.)
Date: Fri, 4 Apr 2008 23:03:47 +0200
Subject: [sdiy] Tau Phaser PCBs ready for shipping
Message-ID: <00a101c89697$63333eb0$0400a8c0@jhsilent>

Hi,

everyone who has pre-ordered boards from my re-run of 20-Stage "Tau" Phaser 
boards should have received an invoice by now.
I've shipped them today to all who have paid already.
Next batch will not go out before 12. April, because I'm on a business trip 
next week.
If anybody is still interested in boards, I have some more for sale.
http://www.jhaible.heim.at/tau/jh_tau.html

JH. 



From music.maker at gte.net  Sat Apr  5 02:01:19 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Fri, 04 Apr 2008 17:01:19 -0700
Subject: [sdiy] Last phLUTe Sample
Message-ID: <200804050001.m3501I8W029976@linux7.lan>

http://electro-music.com/forum/download.php?id=12198

Last sample.

I think this is about the best I can do with this design.

While trying to reduce the transients I noticed that my design was actually working from the bass flute range upward.  Most of the problems with the transients are in the lowest octave.  My original intentions were to include bass flute and I forgot that the tuning ROMs were created with that in mind.

The design was changed to play an octave higher so that the phLUTe's lowest note is middle C instead of an octave lower.  The transients are much less apparent now.

Also, this piece is for strings that do things flutes don't do or do differently.  For example, 2/3 of the way through, in either the cello or viola parts, there is supposed to be a rythmic bowing on one note which when played by phLUTes manifests as rythmic clicks.  

I think that this piece may not the best example for a demo of this instrument, but it has other qualities that demonstrate very flute like behavior.

In an ensemble of instruments such as for jazz or blues, I think the transients would hide in the mix and be less noticable.  In this Mozart piece, there's only the phLUTes so it's very stark.

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From somnium7 at gmail.com  Sat Apr  5 03:39:17 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Fri, 4 Apr 2008 20:39:17 -0500
Subject: [sdiy] Weird Ripple Voltage
Message-ID: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>

More strange power supply problems. This time I have a high pitched
whining in the audio. I traced it back to the devices power supply
where it seems to be originating before the regulator. On the scope I
see a ripple voltage with the usual saw shape but it is shot through
with  lines. Increasing the volts division I can make out a tiny
sawtooth wave riding on the ripple at several times the ripple
frequency.

I disconnected the regulator to verify the origin and sure enough it
coming form the rectifier/filter stage. That stage is a bridge
rectifier with a ring of snubber caps and then the main filter cap and
another 0.1uF cap. Am I looking at a problem with the bridge rectifier
or is one of the snubbers bad?

Mike


From uzs159 at uni-bonn.de  Sat Apr  5 06:06:46 2008
From: uzs159 at uni-bonn.de (=?ISO-8859-1?Q?Ren=E9_Schmitz?=)
Date: Sat, 05 Apr 2008 06:06:46 +0200
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
References: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
Message-ID: <47F6FAD6.70806@uni-bonn.de>

Hi Mike,

mike ruberto schrieb:
> More strange power supply problems. This time I have a high pitched
> whining in the audio. I traced it back to the devices power supply
> where it seems to be originating before the regulator. On the scope I
> see a ripple voltage with the usual saw shape but it is shot through
> with  lines. Increasing the volts division I can make out a tiny
> sawtooth wave riding on the ripple at several times the ripple
> frequency.
> 
> I disconnected the regulator to verify the origin and sure enough it
> coming form the rectifier/filter stage. That stage is a bridge
> rectifier with a ring of snubber caps and then the main filter cap and
> another 0.1uF cap. Am I looking at a problem with the bridge rectifier
> or is one of the snubbers bad?

That could be a resonance from the caps and the inductance of the 
transformer. I'd try to see if changing the snubbers capacitance makes a 
difference in frequency of that ripple.

Cheers,
  Ren?



From somnium7 at gmail.com  Sat Apr  5 06:56:08 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Fri, 4 Apr 2008 23:56:08 -0500
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <47F6FAD6.70806@uni-bonn.de>
References: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
	<47F6FAD6.70806@uni-bonn.de>
Message-ID: <916920440804042156w34b4884dn9ae053e0c5ba1fc@mail.gmail.com>

Hi Ren?,

Ok I will give this a shot. Although, I don't see any evidence of it
at all on the other rail which has the same circuit coming off a
separate winding on the transformer.

Is there any reason not to replace these snubbers with metalized poly
instead of ceramic disc?

Thanks

Mike

On Fri, Apr 4, 2008 at 11:06 PM, Ren? Schmitz <uzs159 at uni-bonn.de> wrote:
> Hi Mike,
>
>  mike ruberto schrieb:
>
>
>
> > More strange power supply problems. This time I have a high pitched
> > whining in the audio. I traced it back to the devices power supply
> > where it seems to be originating before the regulator. On the scope I
> > see a ripple voltage with the usual saw shape but it is shot through
> > with  lines. Increasing the volts division I can make out a tiny
> > sawtooth wave riding on the ripple at several times the ripple
> > frequency.
> >
> > I disconnected the regulator to verify the origin and sure enough it
> > coming form the rectifier/filter stage. That stage is a bridge
> > rectifier with a ring of snubber caps and then the main filter cap and
> > another 0.1uF cap. Am I looking at a problem with the bridge rectifier
> > or is one of the snubbers bad?
> >
>
>  That could be a resonance from the caps and the inductance of the
> transformer. I'd try to see if changing the snubbers capacitance makes a
> difference in frequency of that ripple.
>
>  Cheers,
>   Ren?
>
>



From aaron at receive-transmit.com  Sat Apr  5 12:28:28 2008
From: aaron at receive-transmit.com (Aaron Day)
Date: Sat, 5 Apr 2008 12:28:28 +0200
Subject: [sdiy] (EU) Lots of gear FS. Modular, drum machine, SW, etc.
Message-ID: <393AEE3E-0981-4E20-9E3A-22669D6938BF@receive-transmit.com>

Greetings everybody.

Spring cleaning is here and I'm getting rid of some equipment. Will  
post some more in a few weeks.
All prices + ship.
I am based in Berlin and will ship within the EU. I have SDIY/MOTM/ 
ebay refs if you need. Pay via wire transfer/?berweisung.

Pics available for everything. Please respond offline.

Thanks.

ad


Modular
____________________________________________

CGS VCO. 3U wide, MOTM format. Schaeffer panel, Alpha Pots.

Built by Jan-Arend Czmok. ?180

http://cgs.synth.net/modules/cgs48_vco.html
____________________________________________

MFOS (music from outer space)  Sample and Hold. 1U wide MOTM format.  
Schaeffer panel, Alpha Pots.

Built by Jan-Arend Czmok. ?85



Stompboxes
____________________________________________

Ibanez Sound Tank Series "Thrash Metal"

good condition, no major wear, ?20
____________________________________________

Electro Harmonix Pulsar

mint condition (i.e. unused) + box, instructions, packaging & promo  
disc ?60
____________________________________________



Drummachines
____________________________________________

MFB Kult (V1.0)

mint condition + box, packaging, manual & original PS ?140
____________________________________________

Korg DDM-110 "Super Drums"

Excellent Condition. Printout of manual ?45
____________________________________________

Korg DDM-120 "Super Percussion"

Mint condition in original box with all packaging and manuals.  
Includes original PS.  ?65
____________________________________________
****Buy both Korg boxes = ?100 for the pair***
____________________________________________




Computer, Software, Controller
____________________________________________
Apple Mac Mini Core Duo

1.66GHz, 1GB RAM

Leopard installed, includes some interesting SW.

?400

____________________________________________

Novation 25SL

Good condition, includes original box & USB cable. Display still  
bright, "menu" rotary encoder wobbles 1-1.5mm but has no skip or  
error. ?125

____________________________________________

Ableton Live 6 ?200 (can be upgraded to 7 for ?99, you save ?120)


Apple Logic Audio 7 ?180 (can be upgraded to 8 for ?199, you save ?100)




From rtellason at verizon.net  Sat Apr  5 14:10:20 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sat, 05 Apr 2008 08:10:20 -0400
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
References: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
Message-ID: <200804050810.20926.rtellason@verizon.net>

On Friday 04 April 2008 21:39, mike ruberto wrote:
> More strange power supply problems. This time I have a high pitched
> whining in the audio. I traced it back to the devices power supply
> where it seems to be originating before the regulator. On the scope I
> see a ripple voltage with the usual saw shape but it is shot through
> with  lines. Increasing the volts division I can make out a tiny
> sawtooth wave riding on the ripple at several times the ripple
> frequency.
>
> I disconnected the regulator to verify the origin and sure enough it
> coming form the rectifier/filter stage. That stage is a bridge
> rectifier with a ring of snubber caps and then the main filter cap and
> another 0.1uF cap. Am I looking at a problem with the bridge rectifier
> or is one of the snubbers bad?

One time that I saw something like this,  I had taken a c= 1541 chassis and 
attempted to rig it up to power _two_ c64s.  It didn't work.  No matter what 
I did to isolate them,  as soon as I had two connected I saw some really 
intense high amplitude ripple all over the place,  and neither machine 
worked.

Is it possible that something's interacting with something else there?  Or 
that your regulators are oscillating?  I see where you mention disconnecting 
the regulator,   but it seems possible that something else may be exerting 
some influence there...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From blacet at blacet.com  Sat Apr  5 18:46:42 2008
From: blacet at blacet.com (John Blacet)
Date: Sat, 5 Apr 2008 09:46:42 -0700 (PDT)
Subject: [sdiy] Blacet News for Spring 2008
In-Reply-To: <200804050810.20926.rtellason@verizon.net>
References: <916920440804041839g36c64884s7f177d89a2a60e59@mail.gmail.com>
	<200804050810.20926.rtellason@verizon.net>
Message-ID: <7387.63.167.160.139.1207414002.squirrel@webmail.sonic.net>

Check out our News Page for a really hot special on our Dual Filter Kit!

Also: new Bargain page, new modules, etc.

http://www.blacet.com/news.html

-- 
John Blacet



From jhaible at debitel.net  Sat Apr  5 20:59:38 2008
From: jhaible at debitel.net (JH.)
Date: Sat, 5 Apr 2008 20:59:38 +0200
Subject: [sdiy] String Filter PCB progress
Message-ID: <000501c8974f$34658c60$0400a8c0@jhsilent>

A quick update about my String Filter project
( http://www.jhaible.heim.at/string_filter/jh_string_filter.html ):

Filter section of one board (20 channels) tested.

The new filter topology works great!
And trimming these filters works like a charm.
They are stable, with TL072 chips.
You can use 10% capacitors here, and still you have almost one turn of the 
multiturn trimmers to walk along the peak of the BPF transfer function.

Still have to build the VC resonance and the Stereo Spread function, and the 
on-board PSU. If this works, I'll order a second board to build a complete 
40-band prototype.

JH.

Now Playing: Mike Oldfield, Ommadawn 



From somnium7 at gmail.com  Sat Apr  5 21:05:55 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 14:05:55 -0500
Subject: [sdiy] Desoldering/Rework Stations
Message-ID: <916920440804051205s33d905fes189ae602c49851c4@mail.gmail.com>

It seems I can no-longer live without one of these. I'm real handy
with my old hand tools but I need to speed things up as I have much
work on it's way.'

Any suggestions in the under $500 range?

TIA

Mike


From veronica.merryfield at shaw.ca  Sat Apr  5 21:24:33 2008
From: veronica.merryfield at shaw.ca (Veronica Merryfield)
Date: Sat, 05 Apr 2008 12:24:33 -0700
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <916920440804051205s33d905fes189ae602c49851c4@mail.gmail.com>
References: <916920440804051205s33d905fes189ae602c49851c4@mail.gmail.com>
Message-ID: <F2EA7455-215B-4595-ABB6-E23767605012@shaw.ca>

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail? 
name=WD1001-ND and add a few tips. Get a magnifier as well - they  
stock one at about $80.

They also do tweezer irons but they may be above your current budget.  
A nice pair of ceramic tipped tweezers are useful - the ceramic stops  
the solder sticking to the tweezers when you're holding a component. I  
once had a pair with these little heatsinks on them so you're fingers  
didn't get hot but I can't find a supplier.

On 5-Apr-08, at 12:05 PM, mike ruberto wrote:
> It seems I can no-longer live without one of these. I'm real handy
> with my old hand tools but I need to speed things up as I have much
> work on it's way.'
>
> Any suggestions in the under $500 range?
>
> TIA
>
> Mike
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From somnium7 at gmail.com  Sat Apr  5 22:53:56 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 15:53:56 -0500
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <d55.29743670.35293dcc@aol.com>
References: <d55.29743670.35293dcc@aol.com>
Message-ID: <916920440804051353g79e3b1a8y4e83f90e4528f350@mail.gmail.com>

I'm thinking I have a bad snubber cap. However, before I take any
drastic action I am trying to educate myself in the topics of ringing
and snubber design. So far this has been most helpful...
http://peufeu.free.fr/audio/articles/Snubber%20Networks%20in%20Power%20Supplies.pdf

The math is quite above me though for the most part. Still at least I
have a better idea of what's going on.

Considering the negative rail is not having this fault at all I will
assume the proper values are being used for this supply and start
replacing the snubber caps one by one in the positive rail rectifier.

This whole experience makes me wish I had better test equipment ;-)

Mike

On Sat, Apr 5, 2008 at 3:40 PM,  <KHeck73 at aol.com> wrote:
>
>
>
> I've had some weird experiences using the same AC power circuit that powers
> dimmer controls for lighting. If your lighting is usually on, try switching
> it off and see what happens. For my circumstance, I think it was the square
> wave off the triac making harmonics...  -Karl.
>
>
> In a message dated 4/4/2008 9:41:25 P.M. Eastern Daylight Time,
> somnium7 at gmail.com writes:
> More strange power supply problems. This time I have a high pitched
> whining in the audio. I traced it back to the devices power supply
> where it seems to be originating before the regulator. On the scope I
> see a ripple voltage with the usual saw shape but it is shot through
> with  lines. Increasing the volts division I can make out a tiny
> sawtooth wave riding on the ripple at several times the ripple
> frequency.
>
> I disconnected the regulator to verify the origin and sure enough it
> coming form the rectifier/filter stage. That stage is a bridge
> rectifier with a ring of snubber caps and then the main filter cap and
> another 0.1uF cap. Am I looking at a problem with the bridge rectifier
> or is one of the snubbers bad?
>
> Mike
>
>
>
>
>
> ________________________________
> Planning your summer road trip? Check out AOL Travel Guides.


From somnium7 at gmail.com  Sat Apr  5 23:00:17 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 16:00:17 -0500
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <F2EA7455-215B-4595-ABB6-E23767605012@shaw.ca>
References: <916920440804051205s33d905fes189ae602c49851c4@mail.gmail.com>
	<F2EA7455-215B-4595-ABB6-E23767605012@shaw.ca>
Message-ID: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>

I'm primarily looking for vacuum desoldering for thru-hole components.
It's 99% of what I work on. Something more like this...
http://www.mcmelectronics.com/product/WDD81VIL

Preferably less expensive if possible...

Mike

On Sat, Apr 5, 2008 at 2:24 PM, Veronica Merryfield
<veronica.merryfield at shaw.ca> wrote:
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=WD1001-ND
> and add a few tips. Get a magnifier as well - they stock one at about $80.
>
>  They also do tweezer irons but they may be above your current budget. A
> nice pair of ceramic tipped tweezers are useful - the ceramic stops the
> solder sticking to the tweezers when you're holding a component. I once had
> a pair with these little heatsinks on them so you're fingers didn't get hot
> but I can't find a supplier.
>
>
>
>  On 5-Apr-08, at 12:05 PM, mike ruberto wrote:
>
> >
> >
> >
> > It seems I can no-longer live without one of these. I'm real handy
> > with my old hand tools but I need to speed things up as I have much
> > work on it's way.'
> >
> > Any suggestions in the under $500 range?
> >
> > TIA
> >
> > Mike
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
>
>


From somnium7 at gmail.com  Sat Apr  5 23:21:08 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 16:21:08 -0500
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804051353g79e3b1a8y4e83f90e4528f350@mail.gmail.com>
References: <d55.29743670.35293dcc@aol.com>
	<916920440804051353g79e3b1a8y4e83f90e4528f350@mail.gmail.com>
Message-ID: <916920440804051421i42546308k2e64b22301277bc9@mail.gmail.com>

And according to Cornell Dublier Metallized caps are not recommended
for this application due to limited pulse current handling.

Good thing I checked. I was about to use the metallized ones in my
parts box. I'll have to cannibalize the ceramics off an old television
motherboard I have and test them now.

Mike

On Sat, Apr 5, 2008 at 3:53 PM, mike ruberto <somnium7 at gmail.com> wrote:
> I'm thinking I have a bad snubber cap. However, before I take any
>  drastic action I am trying to educate myself in the topics of ringing
>  and snubber design. So far this has been most helpful...
>  http://peufeu.free.fr/audio/articles/Snubber%20Networks%20in%20Power%20Supplies.pdf
>
>  The math is quite above me though for the most part. Still at least I
>  have a better idea of what's going on.
>
>  Considering the negative rail is not having this fault at all I will
>  assume the proper values are being used for this supply and start
>  replacing the snubber caps one by one in the positive rail rectifier.
>
>  This whole experience makes me wish I had better test equipment ;-)
>
>  Mike
>
>
>
>  On Sat, Apr 5, 2008 at 3:40 PM,  <KHeck73 at aol.com> wrote:
>  >
>  >
>  >
>  > I've had some weird experiences using the same AC power circuit that powers
>  > dimmer controls for lighting. If your lighting is usually on, try switching
>  > it off and see what happens. For my circumstance, I think it was the square
>  > wave off the triac making harmonics...  -Karl.
>  >
>  >
>  > In a message dated 4/4/2008 9:41:25 P.M. Eastern Daylight Time,
>  > somnium7 at gmail.com writes:
>  > More strange power supply problems. This time I have a high pitched
>  > whining in the audio. I traced it back to the devices power supply
>  > where it seems to be originating before the regulator. On the scope I
>  > see a ripple voltage with the usual saw shape but it is shot through
>  > with  lines. Increasing the volts division I can make out a tiny
>  > sawtooth wave riding on the ripple at several times the ripple
>  > frequency.
>  >
>  > I disconnected the regulator to verify the origin and sure enough it
>  > coming form the rectifier/filter stage. That stage is a bridge
>  > rectifier with a ring of snubber caps and then the main filter cap and
>  > another 0.1uF cap. Am I looking at a problem with the bridge rectifier
>  > or is one of the snubbers bad?
>  >
>  > Mike
>  >
>  >
>  >
>  >
>  >
>  > ________________________________
>  > Planning your summer road trip? Check out AOL Travel Guides.
>


From jloffink at austin.rr.com  Sat Apr  5 23:54:09 2008
From: jloffink at austin.rr.com (John Loffink)
Date: Sat, 5 Apr 2008 16:54:09 -0500
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
Message-ID: <001c01c89767$941b6c70$6600a8c0@john>

Hakko 808.  Don't forget to buy the stand which is sold separately. The
combination will run less than $200.

http://www.tequipment.net/Hakko808.html

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com


> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of mike ruberto
> Sent: Saturday, April 05, 2008 4:00 PM
> To: Veronica Merryfield
> Cc: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Desoldering/Rework Stations
> 
> I'm primarily looking for vacuum desoldering for thru-hole components.
> It's 99% of what I work on. Something more like this...
> http://www.mcmelectronics.com/product/WDD81VIL
> 
> Preferably less expensive if possible...
> 



From dougt55 at yahoo.com  Sat Apr  5 23:59:58 2008
From: dougt55 at yahoo.com (Doug Terrebonne)
Date: Sat, 5 Apr 2008 14:59:58 -0700 (PDT)
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
Message-ID: <609295.72320.qm@web81205.mail.mud.yahoo.com>

I got a Hakko 808 for $175 a couple years ago and have been very happy
with it...

Doug

--- mike ruberto <somnium7 at gmail.com> wrote:

> I'm primarily looking for vacuum desoldering for thru-hole
> components.
> It's 99% of what I work on. Something more like this...
> http://www.mcmelectronics.com/product/WDD81VIL
> 
> Preferably less expensive if possible...
> 
> Mike
> 
> On Sat, Apr 5, 2008 at 2:24 PM, Veronica Merryfield
> <veronica.merryfield at shaw.ca> wrote:
> >
>
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=WD1001-ND
> > and add a few tips. Get a magnifier as well - they stock one at
> about $80.
> >
> >  They also do tweezer irons but they may be above your current
> budget. A
> > nice pair of ceramic tipped tweezers are useful - the ceramic stops
> the
> > solder sticking to the tweezers when you're holding a component. I
> once had
> > a pair with these little heatsinks on them so you're fingers didn't
> get hot
> > but I can't find a supplier.
> >
> >
> >
> >  On 5-Apr-08, at 12:05 PM, mike ruberto wrote:
> >
> > >
> > >
> > >
> > > It seems I can no-longer live without one of these. I'm real
> handy
> > > with my old hand tools but I need to speed things up as I have
> much
> > > work on it's way.'
> > >
> > > Any suggestions in the under $500 range?
> > >
> > > TIA
> > >
> > > Mike
> > > _______________________________________________
> > > Synth-diy mailing list
> > > Synth-diy at dropmix.xs4all.nl
> > > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> > >
> >
> >
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From somnium7 at gmail.com  Sun Apr  6 00:11:46 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 17:11:46 -0500
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <001c01c89767$941b6c70$6600a8c0@john>
References: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
	<001c01c89767$941b6c70$6600a8c0@john>
Message-ID: <916920440804051511q223d3bf9o39e21a900090c778@mail.gmail.com>

Oh cool, no wasted bench space. This looks like it might be just what I need...
Thanks!!!

Mike

On Sat, Apr 5, 2008 at 4:54 PM, John Loffink <jloffink at austin.rr.com> wrote:
> Hakko 808.  Don't forget to buy the stand which is sold separately. The
>  combination will run less than $200.
>
>  http://www.tequipment.net/Hakko808.html
>
>  John Loffink
>  The Microtonal Synthesis Web Site
>  http://www.microtonal-synthesis.com
>  The Wavemakers Synthesizer Web Site
>  http://www.wavemakers-synth.com
>
>
>
>
>  > -----Original Message-----
>  > From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>  > bounces at dropmix.xs4all.nl] On Behalf Of mike ruberto
>  > Sent: Saturday, April 05, 2008 4:00 PM
>  > To: Veronica Merryfield
>  > Cc: synth-diy at dropmix.xs4all.nl
>  > Subject: Re: [sdiy] Desoldering/Rework Stations
>  >
>  > I'm primarily looking for vacuum desoldering for thru-hole components.
>  > It's 99% of what I work on. Something more like this...
>  > http://www.mcmelectronics.com/product/WDD81VIL
>  >
>  > Preferably less expensive if possible...
>  >
>
>


From jdec at mindspring.com  Sun Apr  6 00:22:32 2008
From: jdec at mindspring.com (BrightBoy)
Date: Sat, 5 Apr 2008 17:22:32 -0500 (GMT-05:00)
Subject: [sdiy] Desoldering/Rework Stations
Message-ID: <19874597.1207434152786.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>

I thought the desoldering unit of choice around here 
was the Den-On SC-7000Z:

http://www.howardelectronics.com/den-on/sc7000.html

Cheers,

Jeff

-----Original Message-----
>From: Doug Terrebonne <dougt55 at yahoo.com>
>Sent: Apr 5, 2008 4:59 PM
>To: synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] Desoldering/Rework Stations
>
>I got a Hakko 808 for $175 a couple years ago and have been very happy
>with it...
>
>Doug
>
>--- mike ruberto <somnium7 at gmail.com> wrote:
>
>> I'm primarily looking for vacuum desoldering for thru-hole
>> components.
>> It's 99% of what I work on. Something more like this...
>> http://www.mcmelectronics.com/product/WDD81VIL
>> 
>> Preferably less expensive if possible...
>> 
>> Mike
>> 
>> On Sat, Apr 5, 2008 at 2:24 PM, Veronica Merryfield
>> <veronica.merryfield at shaw.ca> wrote:
>> >
>>
>http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=WD1001-ND
>> > and add a few tips. Get a magnifier as well - they stock one at
>> about $80.
>> >
>> >  They also do tweezer irons but they may be above your current
>> budget. A
>> > nice pair of ceramic tipped tweezers are useful - the ceramic stops
>> the
>> > solder sticking to the tweezers when you're holding a component. I
>> once had
>> > a pair with these little heatsinks on them so you're fingers didn't
>> get hot
>> > but I can't find a supplier.
>> >
>> >
>> >
>> >  On 5-Apr-08, at 12:05 PM, mike ruberto wrote:
>> >
>> > >
>> > >
>> > >
>> > > It seems I can no-longer live without one of these. I'm real
>> handy
>> > > with my old hand tools but I need to speed things up as I have
>> much
>> > > work on it's way.'
>> > >
>> > > Any suggestions in the under $500 range?
>> > >
>> > > TIA
>> > >
>> > > Mike
>> > > _______________________________________________
>> > > Synth-diy mailing list
>> > > Synth-diy at dropmix.xs4all.nl
>> > > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> > >
>> >
>> >
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> 
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy





From somnium7 at gmail.com  Sun Apr  6 00:39:25 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 17:39:25 -0500
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <19874597.1207434152786.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
References: <19874597.1207434152786.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
Message-ID: <916920440804051539s78cd3b37x1846dcefe6574272@mail.gmail.com>

This is quite nice too... hmmm decisions decisions.

Thanks!

On Sat, Apr 5, 2008 at 5:22 PM, BrightBoy <jdec at mindspring.com> wrote:
> I thought the desoldering unit of choice around here
>  was the Den-On SC-7000Z:
>
>  http://www.howardelectronics.com/den-on/sc7000.html
>
>  Cheers,
>
>  Jeff
>
>
>  -----Original Message-----
>  >From: Doug Terrebonne <dougt55 at yahoo.com>
>  >Sent: Apr 5, 2008 4:59 PM
>  >To: synth-diy at dropmix.xs4all.nl
>  >Subject: Re: [sdiy] Desoldering/Rework Stations
>  >
>
>
> >I got a Hakko 808 for $175 a couple years ago and have been very happy
>  >with it...
>  >
>  >Doug
>  >
>  >--- mike ruberto <somnium7 at gmail.com> wrote:
>  >
>  >> I'm primarily looking for vacuum desoldering for thru-hole
>  >> components.
>  >> It's 99% of what I work on. Something more like this...
>  >> http://www.mcmelectronics.com/product/WDD81VIL
>  >>
>  >> Preferably less expensive if possible...
>  >>
>  >> Mike
>  >>
>  >> On Sat, Apr 5, 2008 at 2:24 PM, Veronica Merryfield
>  >> <veronica.merryfield at shaw.ca> wrote:
>  >> >
>  >>
>  >http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=WD1001-ND
>  >> > and add a few tips. Get a magnifier as well - they stock one at
>  >> about $80.
>  >> >
>  >> >  They also do tweezer irons but they may be above your current
>  >> budget. A
>  >> > nice pair of ceramic tipped tweezers are useful - the ceramic stops
>  >> the
>  >> > solder sticking to the tweezers when you're holding a component. I
>  >> once had
>  >> > a pair with these little heatsinks on them so you're fingers didn't
>  >> get hot
>  >> > but I can't find a supplier.
>  >> >
>  >> >
>  >> >
>  >> >  On 5-Apr-08, at 12:05 PM, mike ruberto wrote:
>  >> >
>  >> > >
>  >> > >
>  >> > >
>  >> > > It seems I can no-longer live without one of these. I'm real
>  >> handy
>  >> > > with my old hand tools but I need to speed things up as I have
>  >> much
>  >> > > work on it's way.'
>  >> > >
>  >> > > Any suggestions in the under $500 range?
>  >> > >
>  >> > > TIA
>  >> > >
>  >> > > Mike
>  >> > > _______________________________________________
>  >> > > Synth-diy mailing list
>  >> > > Synth-diy at dropmix.xs4all.nl
>  >> > > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>  >> > >
>  >> >
>  >> >
>  >> _______________________________________________
>  >> Synth-diy mailing list
>  >> Synth-diy at dropmix.xs4all.nl
>  >> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>  >>
>  >
>  >_______________________________________________
>  >Synth-diy mailing list
>  >Synth-diy at dropmix.xs4all.nl
>  >http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From alfred.pear at gmail.com  Sun Apr  6 00:47:59 2008
From: alfred.pear at gmail.com (alfred.pear at gmail.com)
Date: Sat, 5 Apr 2008 18:47:59 -0400
Subject: [sdiy] baltimore/d.c. synth building
Message-ID: <ea992b2f0804051547i5c835debiad2853da2a535bbe@mail.gmail.com>

Hi -
Was wondering if there were any people in the Baltimore/D.C. area that
would be willing to give lessons in some of the aspects of electronics
that I'm interested in learning.. I'm at a roughly beginner/middle
level...

Price negotiable..


-AL


From somnium7 at gmail.com  Sun Apr  6 04:06:57 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 21:06:57 -0500
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804051421i42546308k2e64b22301277bc9@mail.gmail.com>
References: <d55.29743670.35293dcc@aol.com>
	<916920440804051353g79e3b1a8y4e83f90e4528f350@mail.gmail.com>
	<916920440804051421i42546308k2e64b22301277bc9@mail.gmail.com>
Message-ID: <916920440804051906h2b5be490y2a601f64aec18fa7@mail.gmail.com>

no luck changing the snubbers. I've replaced them all with no affect.
Looks like I need another strategy.



On Sat, Apr 5, 2008 at 4:21 PM, mike ruberto <somnium7 at gmail.com> wrote:
> And according to Cornell Dublier Metallized caps are not recommended
>  for this application due to limited pulse current handling.
>
>  Good thing I checked. I was about to use the metallized ones in my
>  parts box. I'll have to cannibalize the ceramics off an old television
>  motherboard I have and test them now.
>
>  Mike
>
>
>
>  On Sat, Apr 5, 2008 at 3:53 PM, mike ruberto <somnium7 at gmail.com> wrote:
>  > I'm thinking I have a bad snubber cap. However, before I take any
>  >  drastic action I am trying to educate myself in the topics of ringing
>  >  and snubber design. So far this has been most helpful...
>  >  http://peufeu.free.fr/audio/articles/Snubber%20Networks%20in%20Power%20Supplies.pdf
>  >
>  >  The math is quite above me though for the most part. Still at least I
>  >  have a better idea of what's going on.
>  >
>  >  Considering the negative rail is not having this fault at all I will
>  >  assume the proper values are being used for this supply and start
>  >  replacing the snubber caps one by one in the positive rail rectifier.
>  >
>  >  This whole experience makes me wish I had better test equipment ;-)
>  >
>  >  Mike
>  >
>  >
>  >
>  >  On Sat, Apr 5, 2008 at 3:40 PM,  <KHeck73 at aol.com> wrote:
>  >  >
>  >  >
>  >  >
>  >  > I've had some weird experiences using the same AC power circuit that powers
>  >  > dimmer controls for lighting. If your lighting is usually on, try switching
>  >  > it off and see what happens. For my circumstance, I think it was the square
>  >  > wave off the triac making harmonics...  -Karl.
>  >  >
>  >  >
>  >  > In a message dated 4/4/2008 9:41:25 P.M. Eastern Daylight Time,
>  >  > somnium7 at gmail.com writes:
>  >  > More strange power supply problems. This time I have a high pitched
>  >  > whining in the audio. I traced it back to the devices power supply
>  >  > where it seems to be originating before the regulator. On the scope I
>  >  > see a ripple voltage with the usual saw shape but it is shot through
>  >  > with  lines. Increasing the volts division I can make out a tiny
>  >  > sawtooth wave riding on the ripple at several times the ripple
>  >  > frequency.
>  >  >
>  >  > I disconnected the regulator to verify the origin and sure enough it
>  >  > coming form the rectifier/filter stage. That stage is a bridge
>  >  > rectifier with a ring of snubber caps and then the main filter cap and
>  >  > another 0.1uF cap. Am I looking at a problem with the bridge rectifier
>  >  > or is one of the snubbers bad?
>  >  >
>  >  > Mike
>  >  >
>  >  >
>  >  >
>  >  >
>  >  >
>  >  > ________________________________
>  >  > Planning your summer road trip? Check out AOL Travel Guides.
>  >
>


From somnium7 at gmail.com  Sun Apr  6 06:04:34 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 5 Apr 2008 23:04:34 -0500
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804051906h2b5be490y2a601f64aec18fa7@mail.gmail.com>
References: <d55.29743670.35293dcc@aol.com>
	<916920440804051353g79e3b1a8y4e83f90e4528f350@mail.gmail.com>
	<916920440804051421i42546308k2e64b22301277bc9@mail.gmail.com>
	<916920440804051906h2b5be490y2a601f64aec18fa7@mail.gmail.com>
Message-ID: <916920440804052104t542830f8l593793c08b104d27@mail.gmail.com>

Got it! I case I missed something I started working my way back into
the power supply from the rectifier and noticed a very large spike on
the base of a pass transistor. Changed the transistor and problem
solved.

Very strange, because the output voltages were correct with the faulty
transistor. This turned out to be an interesting challenge. Learned a
little something about snubber circuits because of it too.

Mike

On Sat, Apr 5, 2008 at 9:06 PM, mike ruberto <somnium7 at gmail.com> wrote:
> no luck changing the snubbers. I've replaced them all with no affect.
>  Looks like I need another strategy.
>
>
>
>
>
>  On Sat, Apr 5, 2008 at 4:21 PM, mike ruberto <somnium7 at gmail.com> wrote:
>  > And according to Cornell Dublier Metallized caps are not recommended
>  >  for this application due to limited pulse current handling.
>  >
>  >  Good thing I checked. I was about to use the metallized ones in my
>  >  parts box. I'll have to cannibalize the ceramics off an old television
>  >  motherboard I have and test them now.
>  >
>  >  Mike
>  >
>  >
>  >
>  >  On Sat, Apr 5, 2008 at 3:53 PM, mike ruberto <somnium7 at gmail.com> wrote:
>  >  > I'm thinking I have a bad snubber cap. However, before I take any
>  >  >  drastic action I am trying to educate myself in the topics of ringing
>  >  >  and snubber design. So far this has been most helpful...
>  >  >  http://peufeu.free.fr/audio/articles/Snubber%20Networks%20in%20Power%20Supplies.pdf
>  >  >
>  >  >  The math is quite above me though for the most part. Still at least I
>  >  >  have a better idea of what's going on.
>  >  >
>  >  >  Considering the negative rail is not having this fault at all I will
>  >  >  assume the proper values are being used for this supply and start
>  >  >  replacing the snubber caps one by one in the positive rail rectifier.
>  >  >
>  >  >  This whole experience makes me wish I had better test equipment ;-)
>  >  >
>  >  >  Mike
>  >  >
>  >  >
>  >  >
>  >  >  On Sat, Apr 5, 2008 at 3:40 PM,  <KHeck73 at aol.com> wrote:
>  >  >  >
>  >  >  >
>  >  >  >
>  >  >  > I've had some weird experiences using the same AC power circuit that powers
>  >  >  > dimmer controls for lighting. If your lighting is usually on, try switching
>  >  >  > it off and see what happens. For my circumstance, I think it was the square
>  >  >  > wave off the triac making harmonics...  -Karl.
>  >  >  >
>  >  >  >
>  >  >  > In a message dated 4/4/2008 9:41:25 P.M. Eastern Daylight Time,
>  >  >  > somnium7 at gmail.com writes:
>  >  >  > More strange power supply problems. This time I have a high pitched
>  >  >  > whining in the audio. I traced it back to the devices power supply
>  >  >  > where it seems to be originating before the regulator. On the scope I
>  >  >  > see a ripple voltage with the usual saw shape but it is shot through
>  >  >  > with  lines. Increasing the volts division I can make out a tiny
>  >  >  > sawtooth wave riding on the ripple at several times the ripple
>  >  >  > frequency.
>  >  >  >
>  >  >  > I disconnected the regulator to verify the origin and sure enough it
>  >  >  > coming form the rectifier/filter stage. That stage is a bridge
>  >  >  > rectifier with a ring of snubber caps and then the main filter cap and
>  >  >  > another 0.1uF cap. Am I looking at a problem with the bridge rectifier
>  >  >  > or is one of the snubbers bad?
>  >  >  >
>  >  >  > Mike
>  >  >  >
>  >  >  >
>  >  >  >
>  >  >  >
>  >  >  >
>  >  >  > ________________________________
>  >  >  > Planning your summer road trip? Check out AOL Travel Guides.
>  >  >
>  >
>


From m.bareille at free.fr  Sun Apr  6 07:19:21 2008
From: m.bareille at free.fr (m.bareille at free.fr)
Date: Sun, 06 Apr 2008 07:19:21 +0200
Subject: [sdiy] Quantix-8 Wavetable / Quantizer important update
Message-ID: <1207459161.47f85d59bd591@imp.free.fr>

Hello,

I have updated the Quantix 8 page :

The schematic, BOM, pcb implant are online and ... the freeware Wavetable
MIDI Editor software for PC is now released freeware here:

http://m.bareille.free.fr/modular1/quantix8/quantix8.htm

Diyers interested by one (or many) pcbs + PIC with firmware, please contact me.
I need to evaluate if there is enough interest from builders for this module and
if yes the first pcb batch volume. Feel free to carry this new to other synth
diy places...

Cheers,

Marc B.


From m.bareille at free.fr  Sun Apr  6 07:55:38 2008
From: m.bareille at free.fr (Marc Bareille)
Date: Sun, 06 Apr 2008 07:55:38 +0200
Subject: [sdiy] Quantix-8 Wavetable / Quantizer important update
In-Reply-To: <1207459161.47f85d59bd591@imp.free.fr>
References: <1207459161.47f85d59bd591@imp.free.fr>
Message-ID: <47F865DA.2070109@free.fr>

m.bareille at free.fr a ?crit :
> Hello,
>
> I have updated the Quantix 8 page :
>
> The schematic, BOM, pcb implant are online and ... the freeware Wavetable
> MIDI Editor software for PC is now released freeware here:
>
> http://m.bareille.free.fr/modular1/quantix8/quantix8.htm
>
> Diyers interested by one (or many) pcbs + PIC with firmware, please contact me.
> I need to evaluate if there is enough interest from builders for this module and
> if yes the first pcb batch volume. Feel free to carry this new to other synth
> diy places...
>
> Cheers,
>
> Marc B.
>
>
>   



From aym-htnys at teaser.fr  Sun Apr  6 10:53:34 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Sun, 6 Apr 2008 10:53:34 +0200
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
References: <916920440804051205s33d905fes189ae602c49851c4@mail.gmail.com>
	<F2EA7455-215B-4595-ABB6-E23767605012@shaw.ca>
	<916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
Message-ID: <20080406085334.GB31723@aym.net2.nerim.net>

On 2008-04-05 16:00 -0500, mike ruberto wrote:

> I'm primarily looking for vacuum desoldering for thru-hole components.
> It's 99% of what I work on. Something more like this...
> http://www.mcmelectronics.com/product/WDD81VIL

- Heating desoldering pump (like a soldering iron with a tubular
  tip fitted to a spring-activated piston).
- Compressor from a dead fridge.
- 1 m of tubing.
- Door bell switch.

Remove the piston from the desoldering tool and plug the
compressor into it instead. Mount the door bell switch as a pedal,
in series with the compressor. Total cost maybe 30 dollars plus
your time.

Don't know how this frankenpump compares to commercial desoldering
stations but I know that my father was satisfied with it after
reworking hundreds or thousands of boards for his clients.

Radiospares used to sell a suitable 30 W heating desoldering pump.
As I recall it was made by a company in the US Mid-West.

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From rtellason at verizon.net  Sun Apr  6 13:32:20 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sun, 06 Apr 2008 07:32:20 -0400
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <916920440804052104t542830f8l593793c08b104d27@mail.gmail.com>
References: <d55.29743670.35293dcc@aol.com>
	<916920440804051906h2b5be490y2a601f64aec18fa7@mail.gmail.com>
	<916920440804052104t542830f8l593793c08b104d27@mail.gmail.com>
Message-ID: <200804060732.20845.rtellason@verizon.net>

On Sunday 06 April 2008 00:04, mike ruberto wrote:
> Got it! I case I missed something I started working my way back into
> the power supply from the rectifier and noticed a very large spike on
> the base of a pass transistor. Changed the transistor and problem
> solved.
>
> Very strange, because the output voltages were correct with the faulty
> transistor. This turned out to be an interesting challenge. Learned a
> little something about snubber circuits because of it too.
>
> Mike

Do you know what the problem was with the transistor?


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From beschaving at gmail.com  Sun Apr  6 18:43:07 2008
From: beschaving at gmail.com (|||||||||| ||||||||||)
Date: Sun, 6 Apr 2008 18:43:07 +0200
Subject: [sdiy] Using shielded cable with banana plugs?
Message-ID: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>

Hi everyone,

I'm planning to build a cable snake to run my Serge modules into a
16x16 matrix. There will be 32 cables with Pomona-brand banana plugs
on the one end, all coming together on a Sub-D connector on the other
end.

Considering that banana plugs just have a single "tip", no ground,
would there be any benefit to using shielded cables for this?
I mean, if the braided wires on the outside of a shielded cable aren't
actually connected to anything, does it still protect the signal from
interference?

Thanks for any tips!

Alex


From somnium7 at gmail.com  Sun Apr  6 18:51:44 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sun, 6 Apr 2008 12:51:44 -0400
Subject: [sdiy] Weird Ripple Voltage
In-Reply-To: <200804060732.20845.rtellason@verizon.net>
References: <d55.29743670.35293dcc@aol.com>
	<916920440804051906h2b5be490y2a601f64aec18fa7@mail.gmail.com>
	<916920440804052104t542830f8l593793c08b104d27@mail.gmail.com>
	<200804060732.20845.rtellason@verizon.net>
Message-ID: <916920440804060951h34089d2j257155198d206344@mail.gmail.com>

It seems there's nothing wrong with the transistor itself. It turned
out to be the wrong transistor. Apparently somebody replaced the part
at some point with what they thought was a viable cross reference. But
the compatibility just wasn't right.

I haven't done anything beyond the simplest of tests but it looks like
a perfectly good transistor.

Mike

On Sun, Apr 6, 2008 at 7:32 AM, Roy J. Tellason <rtellason at verizon.net> wrote:
> On Sunday 06 April 2008 00:04, mike ruberto wrote:
>  > Got it! I case I missed something I started working my way back into
>  > the power supply from the rectifier and noticed a very large spike on
>  > the base of a pass transistor. Changed the transistor and problem
>  > solved.
>  >
>  > Very strange, because the output voltages were correct with the faulty
>  > transistor. This turned out to be an interesting challenge. Learned a
>  > little something about snubber circuits because of it too.
>  >
>  > Mike
>
>  Do you know what the problem was with the transistor?
>
>
>
>  --
>  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  ablest -- form of life in this section of space,  a critter that can
>  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  -
>  Information is more dangerous than cannon to a society ruled by lies. --James
>  M Dakin
>
>  _______________________________________________
>
>
> Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From resonant at hoohahrecords.com  Sun Apr  6 19:13:35 2008
From: resonant at hoohahrecords.com (Dave Magnuson)
Date: Sun, 6 Apr 2008 13:13:35 -0400
Subject: [sdiy] Using shielded cable with banana plugs?
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
Message-ID: <003001c89809$8d1aca90$6501a8c0@HypoLuxa>

Hi Alex

There is no benefit to a disconnected shield.

However - you mention that this is a fan-out from D-sub to bananas... You 
could always ground the shields at the D-Sub end. This is considered a 
"telescoping ground" and should help.

Dave


----- Original Message ----- 
From: "|||||||||| ||||||||||" <beschaving at gmail.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, April 06, 2008 12:43 PM
Subject: [sdiy] Using shielded cable with banana plugs?


> Hi everyone,
>
> I'm planning to build a cable snake to run my Serge modules into a
> 16x16 matrix. There will be 32 cables with Pomona-brand banana plugs
> on the one end, all coming together on a Sub-D connector on the other
> end.
>
> Considering that banana plugs just have a single "tip", no ground,
> would there be any benefit to using shielded cables for this?
> I mean, if the braided wires on the outside of a shielded cable aren't
> actually connected to anything, does it still protect the signal from
> interference?
>
> Thanks for any tips!
>
> Alex
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From Peter.Ullrich at kapsch.net  Sun Apr  6 20:52:34 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Sun, 6 Apr 2008 20:52:34 +0200
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <19874597.1207434152786.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
References: <19874597.1207434152786.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B05@S060VS20.kapsch.co.at>


Hi from Austria!

>I thought the desoldering unit of choice around here
>was the Den-On SC-7000Z:
>
>http://www.howardelectronics.com/den-on/sc7000.html

I have this tool at work for about 10 years now and it works very well!
So I can really recommend it!

Before I got it we had quite old tools from Pace but they had no enough
air power...

Ciao
Peter

http://www.ullrich.at.tt



From beschaving at gmail.com  Sun Apr  6 23:33:03 2008
From: beschaving at gmail.com (beschaving at gmail.com)
Date: Sun, 6 Apr 2008 23:33:03 +0200
Subject: [sdiy] Using shielded cable with banana plugs?
In-Reply-To: <003001c89809$8d1aca90$6501a8c0@HypoLuxa>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<003001c89809$8d1aca90$6501a8c0@HypoLuxa>
Message-ID: <617719FE-334B-4B4E-9404-2F0CC9C76380@gmail.com>

ah ok, so I'd have to solder all the shields from the 32 cables  
together at a ground point somewhere?

since I'll be using a 37-pin d-sub (they don't make 32 pin ones,  
afaik) I suppose I could solder all the shields to a spare pin there,  
and connect that to ground, although I fear this will become a mess...

thank you!



On Apr 6, 2008, at 19:13, "Dave Magnuson" <resonant at hoohahrecords.com>  
wrote:

> Hi Alex
>
> There is no benefit to a disconnected shield.
>
> However - you mention that this is a fan-out from D-sub to  
> bananas... You could always ground the shields at the D-Sub end.  
> This is considered a "telescoping ground" and should help.
>
> Dave
>
>
> ----- Original Message ----- From: "|||||||||| ||||||||||" <beschaving at gmail.com 
> >
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Sunday, April 06, 2008 12:43 PM
> Subject: [sdiy] Using shielded cable with banana plugs?
>
>
>> Hi everyone,
>>
>> I'm planning to build a cable snake to run my Serge modules into a
>> 16x16 matrix. There will be 32 cables with Pomona-brand banana plugs
>> on the one end, all coming together on a Sub-D connector on the other
>> end.
>>
>> Considering that banana plugs just have a single "tip", no ground,
>> would there be any benefit to using shielded cables for this?
>> I mean, if the braided wires on the outside of a shielded cable  
>> aren't
>> actually connected to anything, does it still protect the signal from
>> interference?
>>
>> Thanks for any tips!
>>
>> Alex
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From beschaving at gmail.com  Sun Apr  6 23:48:15 2008
From: beschaving at gmail.com (beschaving at gmail.com)
Date: Sun, 6 Apr 2008 23:48:15 +0200
Subject: [sdiy] alternatives to d-sub?
Message-ID: <2B7F47DE-4E11-4D99-BF17-42E62554DA8D@gmail.com>



hi,

I just wanted to check if anyone has recommendations for alternatives  
to d-sub connectors...  I'm looking for a 32-pin connector that offers  
a little more room for my limited soldering skills...

I'm making a cable snake with 32 banana plugs on the individual ends,  
and they should all come together at the other end.

what else is out there with 32 or more pins?

there are no 32-pin d-subs, right? the closest I found is 37.

thanks for any tips!
alex


From jdec at mindspring.com  Mon Apr  7 01:48:56 2008
From: jdec at mindspring.com (BrightBoy)
Date: Sun, 6 Apr 2008 19:48:56 -0400 (GMT-04:00)
Subject: [sdiy] alternatives to d-sub?
Message-ID: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>

>I just wanted to check if anyone has recommendations for alternatives  
>to d-sub connectors...  I'm looking for a 32-pin connector that offers  
>a little more room for my limited soldering skills...

There is always the round, industrial Amphenol connectors:

http://upload.wikimedia.org/wikipedia/commons/e/ee/Amphenol_16pin_male_front.jpg

Not exactly cheap but they are rugged.

Cheers,

Jeff





From pfperry at melbpc.org.au  Mon Apr  7 04:53:40 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 7 Apr 2008 12:53:40 +1000
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
Message-ID: <001501c8985a$95d964b0$8501a8c0@ice9>

If you are making just the one unit - whatever it is - there is no reason
why you have to use only one cable.
It might be easier to split the cable into two, or even more.

paul perry Melbourne Australia



-----Original Message-----
>I just wanted to check if anyone has recommendations for alternatives  
>to d-sub connectors...  I'm looking for a 32-pin connector that offers  
>a little more room for my limited soldering skills...




From blincoln at eventualdecline.com  Mon Apr  7 09:28:03 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 07 Apr 2008 00:28:03 -0700
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
References: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
Message-ID: <47F9CD03.406@eventualdecline.com>

There are a number of round and square variations on that theme used in 
military and medical applications. The medical ones at least even come 
in different colours to make it obvious which plug out of several goes 
into which receptacle.

Alex, if it helps, you should be able to get some crimp D-sub connectors 
instead of soldering them. You might also consider a Centronics 
connector since they don't have pins to bend like D-sub.

BrightBoy wrote:
> There is always the round, industrial Amphenol connectors:
>
> http://upload.wikimedia.org/wikipedia/commons/e/ee/Amphenol_16pin_male_front.jpg
>
> Not exactly cheap but they are rugged


From Florian.Anwander at consol.de  Mon Apr  7 10:00:28 2008
From: Florian.Anwander at consol.de (Florian Anwander)
Date: Mon, 07 Apr 2008 10:00:28 +0200
Subject: [sdiy] Using shielded cable with banana plugs?
In-Reply-To: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
Message-ID: <47F9D49C.70900@consol.de>

Hi

> I'm planning to build a cable snake to run my Serge modules into a
> 16x16 matrix. 
If the matrix is a standalone box, you should ground the housing of the 
matrix too.

Florian


From Florian.Anwander at consol.de  Mon Apr  7 10:09:11 2008
From: Florian.Anwander at consol.de (Florian Anwander)
Date: Mon, 07 Apr 2008 10:09:11 +0200
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <2B7F47DE-4E11-4D99-BF17-42E62554DA8D@gmail.com>
References: <2B7F47DE-4E11-4D99-BF17-42E62554DA8D@gmail.com>
Message-ID: <47F9D6A7.7090701@consol.de>

Hi Alex

In the German broadcasting and studio scene these connectors are very
common:
http://www.hinkel-elektronik.de/shop/1917.html
I like them very much, because in the housing there is plenty of room,
and usually you do have enough space for soldering.

Look out for "DIN 41622" as the main descriptor.

Florian



From aym-htnys at teaser.fr  Mon Apr  7 10:19:10 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Mon, 7 Apr 2008 10:19:10 +0200
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <2B7F47DE-4E11-4D99-BF17-42E62554DA8D@gmail.com>
References: <2B7F47DE-4E11-4D99-BF17-42E62554DA8D@gmail.com>
Message-ID: <20080407081909.GC31723@aym.net2.nerim.net>

On 2008-04-06 23:48 +0200, beschaving at gmail.com wrote:

> I just wanted to check if anyone has recommendations for
> alternatives to d-sub connectors...  I'm looking for a 32-pin
> connector that offers a little more room for my limited
> soldering skills...
>
> I'm making a cable snake with 32 banana plugs on the individual
> ends, and they should all come together at the other end.
>
> what else is out there with 32 or more pins?

Can't give any specific recommendation but remember that

- all other things being equal, round connectors are more
  difficult to solder than rectangular connectors because most
  pins are surrounded by other pins,

- while soldering, it is good to have the connector mated to its
  opposite sex counterpart as that helps keep the pins in place in
  case the plastic melts. (Please note : the /connector/.)

The only multi-pin connector that is easier to solder than a sub-D
that I can think of is one with removable pins, like AMP/Tyco CPC
(expensive) or those old V.35 connectors :

  http://www.atel.com.pl/produkt.php?hash=01482&dispLang=EN

CEEP, FCI and Tyco make sub-D shells with removable contacts.

> there are no 32-pin d-subs, right? the closest I found is 37.

Correct.

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From synthjunk at gmail.com  Mon Apr  7 10:19:39 2008
From: synthjunk at gmail.com (synth junk)
Date: Mon, 7 Apr 2008 01:19:39 -0700
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <47F9CD03.406@eventualdecline.com>
References: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
	<47F9CD03.406@eventualdecline.com>
Message-ID: <7790ca750804070119l4cf14a7bk613fca357f3a1a1e@mail.gmail.com>

Jones (Cinch Jones) connectors can be  used for such applications.

http://www.cinch.com/view_product_line.cinch?id=29

They make them with up to 33 connectors. They're not "high tech" but
they're easy to work with.

david

On 4/7/08, Ben Lincoln <blincoln at eventualdecline.com> wrote:
> There are a number of round and square variations on that theme used in
> military and medical applications. The medical ones at least even come in
> different colours to make it obvious which plug out of several goes into
> which receptacle.
>
>  Alex, if it helps, you should be able to get some crimp D-sub connectors
> instead of soldering them. You might also consider a Centronics connector
> since they don't have pins to bend like D-sub.
>
>  BrightBoy wrote:
>
> > There is always the round, industrial Amphenol connectors:
> >
> >
> http://upload.wikimedia.org/wikipedia/commons/e/ee/Amphenol_16pin_male_front.jpg
> >
> > Not exactly cheap but they are rugged
> >
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From batzman-nr at all-electric.com  Mon Apr  7 10:22:40 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Mon, 07 Apr 2008 17:52:40 +0930
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <47F9D49C.70900@consol.de>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
Message-ID: <5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>

Y-ellow Humans.
         I'd be wondering if anyone has any inside experience with one of 
the above Behringer boxes by any chance? I have a small opportunity to get 
one if it might solve a problem. But I'm not sure it will.

I found a site with lots of nice porn shots of it. Seems it's full of THAT 
corp 2159 VCA chips. They're supposed to be good aren't they?

http://pics.stromnet.se/index.php?subdir=2005/2005-11-29-ETA-Auktion_Prylar/Behringer%20Cybermix%20CM8000

That withstanding, I'm more concerned about it's functionality. Software 
and controllability. That kind of thing.

I don't have a data sheet on the 2159 but from what I gather it's a single 
VCA. There are 32 of them and the front panel has 32 sections. Which, I'm 
led to believe is designed to sit across the inserts of a mixer and provide 
some level of automation. What I don't get is the labelling on the sockets. 
"Tip = in/Ring = out" etc. So what is the other send/return socket?

My intention would be to hack the I/Os and bus it to 16 stereo channels. 
Mainly pre-set as a rack mixer. I've already got an automated main console. 
So I'm just wondering what the software is capable of and what you can do 
with MIDI on it.

Seems to be an otherwise dirth of information out there on this box so I'm 
just wondering if anyone has any intimate connection with one.

Thanks in advance.
Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From theatomlabspt at gmail.com  Mon Apr  7 11:01:13 2008
From: theatomlabspt at gmail.com (The Atomlabs PT)
Date: Mon, 7 Apr 2008 10:01:13 +0100
Subject: [sdiy] Test
Message-ID: <000f01c8988d$efde19a0$0201a8c0@atomlabs>

testing 1.2.3

please ignore :)


From blincoln at eventualdecline.com  Mon Apr  7 15:28:07 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 07 Apr 2008 06:28:07 -0700
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
Message-ID: <47FA2167.5050606@eventualdecline.com>

Since it's a mixer automation product, I imagine the send/return takes 
the place of the per-channel send/return on the mixer it's connected to. 
I wasn't able to find anything substantial about it either, but it would 
make sense that you could at least toggle the send/return loop on and 
off, and probably control the wet/dry mix - otherwise why would 
Behringer have doubled the number of plugs when you could just put the 
processing inline after the Cybermix?

Batz Goodfortune wrote:
> Y-ellow Humans.
>         I'd be wondering if anyone has any inside experience with one 
> of the above Behringer boxes by any chance? I have a small opportunity 
> to get one if it might solve a problem. But I'm not sure it will.
>
> I found a site with lots of nice porn shots of it. Seems it's full of 
> THAT corp 2159 VCA chips. They're supposed to be good aren't they?
>
> http://pics.stromnet.se/index.php?subdir=2005/2005-11-29-ETA-Auktion_Prylar/Behringer%20Cybermix%20CM8000 
>
>
> That withstanding, I'm more concerned about it's functionality. 
> Software and controllability. That kind of thing.
>
> I don't have a data sheet on the 2159 but from what I gather it's a 
> single VCA. There are 32 of them and the front panel has 32 sections. 
> Which, I'm led to believe is designed to sit across the inserts of a 
> mixer and provide some level of automation. What I don't get is the 
> labelling on the sockets. "Tip = in/Ring = out" etc. So what is the 
> other send/return socket?
>
> My intention would be to hack the I/Os and bus it to 16 stereo 
> channels. Mainly pre-set as a rack mixer. I've already got an 
> automated main console. So I'm just wondering what the software is 
> capable of and what you can do with MIDI on it.
>
> Seems to be an otherwise dirth of information out there on this box so 
> I'm just wondering if anyone has any intimate connection with one.


From Peter.Ullrich at kapsch.net  Mon Apr  7 16:08:21 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 7 Apr 2008 16:08:21 +0200
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <47FA2167.5050606@eventualdecline.com>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B6FFD56C6@S060VS20.kapsch.co.at>


Hi!

As Behringer has no more info for it on his webpage:

I have the CM8000 at home (boxed in the cellar waiting for my home
studio beeing ready for installation) and should have the documentation
And the software for it (I got it from the Behringer support years ago).

I have to dig it out of one of my USB harddisks and could send it to
You, or maybe someone has some space left on a webpage so that I can
put it up there.

Ciao
Peter

http://www.ullrich.at.tt



From batzman-nr at all-electric.com  Mon Apr  7 17:16:08 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Tue, 08 Apr 2008 00:46:08 +0930
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <66989A9506070B43A3B606F3009CB90A3B6FFD56C6@S060VS20.kapsch
	.co.at>
References: <47FA2167.5050606@eventualdecline.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
Message-ID: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>

Y-ellow Peter, Ben, et all.
         Thanks for that. Seems to be the consensus that the send/ret jack 
doubles as some kind of quasi convenience. Though it would seem that having 
them on the same TRS socket isn't all that convenient.

If you take a look at the photos on that site I posted, you'll notice that 
the only ICs adjacent to the VCA chip are a couple of Op Amp packages. A 
TL074 and some kind of 8 pin device. (Might even be a dual sample/hold 
chip) Each channel seems to be accompanied by a pair of trim pots. I can't 
see anything that suggests any further switching components per channel. 
Which is what threw me about the extra jacks. I would have expected there 
to be some kind of switching on the Mo-Bo but there was none.

So all I can glean from these photos is that it's got MIDI and RS232. It 
also seems to have SMPTE I/O of some kind. And is powered by a HC11.

I need to make a decision whether to make a play for this thing within the 
next day or two. I know I could sum the outputs fairly easily. But I guess 
now it seems I have to find some kind of special software to run it.

At it's most basic, I just need to mix a bunch of incoming stereo sources 
from Analogue synths etc. Each synth has it's own autonomous mix/FX chain. 
The only thing I need to do is adjust each synth's level to normalize them. 
But if I could also use it like an automated noise gate, where I only have 
to have them in line as needed, then that would be a bonus. This is where 
this behringer box and it's VCAs would come in.

I've tried various methods of doing this in the past but none of them have 
been quiet enough. OTAs are too noisy outright. The digital control blocks 
have zipper noise. Just plain switching causes pops and sudden introduction 
of noise. And to build something like this from scratch would be both 
prohibitively expensive and time consuming. And there-in lies the rub.

I don't want to find myself having to learn and write HC11 code.Or any code 
for that matter. I now just need to know that I can slot it in with some 
mods and tell it to behave and it will. So I'm a bit concerned about this 
RS232 notion and getting whatever software is required. More to the point, 
that means it's not platform independent and likely to become redundant.

On the hardware side though, it looks like a pretty open structure from a 
hacking point of view.

But from the general consensus here it seems like it's worth making a play 
for. And If so, I'll take you up on that offer Peter. You can always use my 
FTP and I'm happy to host some files there if anyone else needs this stuff.

Thanks once again all. Very much appreciated.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From beschaving at gmail.com  Mon Apr  7 20:00:22 2008
From: beschaving at gmail.com (|||||||||| ||||||||||)
Date: Mon, 7 Apr 2008 20:00:22 +0200
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <7790ca750804070119l4cf14a7bk613fca357f3a1a1e@mail.gmail.com>
References: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
	<47F9CD03.406@eventualdecline.com>
	<7790ca750804070119l4cf14a7bk613fca357f3a1a1e@mail.gmail.com>
Message-ID: <de53b7a90804071100o48e23336v9e12266ad56ce208@mail.gmail.com>

Thank you all very much for the helpful suggestions!

I will look into all the details...

Alex


From beschaving at gmail.com  Mon Apr  7 20:24:59 2008
From: beschaving at gmail.com (|||||||||| ||||||||||)
Date: Mon, 7 Apr 2008 20:24:59 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
Message-ID: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>

Hi everyone,

I'm currently thinking about alternative ways of making connections on
a modular synth, particularly of the primitive, somewhat random kind.
For example, German Synthi AKS improviser Thomas Lehn sticks bits of
metal in the Synthi "Prestopatch" slot and wiggles it around, to
short-circuit between various modules and make all kinds of sudden
complex noises...This is what I'm into as well. (It doesn't seem to
harm his Synthi, by the way).

I'd love to hear about other ways that people are "mechanically"
interfacing with their synths. I vaguely remember seeing some design
that just had a number of metal nails sticking up, for example, that
one would either touch or clamp crocodile cables to.
I also seem to remember something with a metal ball rolling around
another bed of nails?

Sorry to jump from lurking to taking up so much bandwidth all of a
sudden, by the way...

Thank you for any hints, suggestions etc!

Alex


From blincoln at eventualdecline.com  Mon Apr  7 20:56:36 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 7 Apr 2008 11:56:36 -0700 (PDT)
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
Message-ID: <52706.38.112.225.84.1207594596.squirrel@www.eventualdecline.com>

If I were going to do something like that, I would definitely use the
latter type of approach - make some sort of adapter between the factory
patch panel and something else. That way you won't end up physically
damaging the real connectors. You could also use it as an opportunity to
*not* make connections to potentially dangerous connectors (power, etc)
that shouldn't be routed to the other pins.

On Mon, April 7, 2008 11:24 am, |||||||||| |||||||||| said:
> Hi everyone,
>
> I'm currently thinking about alternative ways of making connections on
> a modular synth, particularly of the primitive, somewhat random kind.
> For example, German Synthi AKS improviser Thomas Lehn sticks bits of
> metal in the Synthi "Prestopatch" slot and wiggles it around, to
> short-circuit between various modules and make all kinds of sudden
> complex noises...This is what I'm into as well. (It doesn't seem to
> harm his Synthi, by the way).
>
> I'd love to hear about other ways that people are "mechanically"
> interfacing with their synths. I vaguely remember seeing some design
> that just had a number of metal nails sticking up, for example, that
> one would either touch or clamp crocodile cables to.
> I also seem to remember something with a metal ball rolling around
> another bed of nails?
>
> Sorry to jump from lurking to taking up so much bandwidth all of a
> sudden, by the way...
>
> Thank you for any hints, suggestions etc!
>
> Alex
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>




From electronicpresskit at gmail.com  Mon Apr  7 21:18:32 2008
From: electronicpresskit at gmail.com (epk)
Date: Mon, 7 Apr 2008 12:18:32 -0700
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
Message-ID: <5BECB660-3332-4743-9B5F-D001B7E5F797@gmail.com>

Driscoll modular stuff that have traces on the rear of the faceplate  
and sometimes when a panel flexes it will alter the way the patch  
sounds.  I'm assuming this is because the outer 1/8 inch of the  
faceplate is ground and the connection is sometimes better than others.

The banana jacks on Driscoll modules are all metal too, so fingers or  
other conductor will change the patch on touch.  Dunno if anyone  
still makes all metal banana jacks though.  If they are available,  
it'd be fun to make a bunch of cables or a snake with all metal  
banana jacks at one end, then hang it so the jacks are upside down  
and shake it around so random momentary connections are made.  If the  
cable was the right length you could even make gestures with it or  
attach it to your pants and get your Elvis on!

epk

On Apr 7, 2008, at 11:24 AM, |||||||||| |||||||||| wrote:

> Hi everyone,
>
> I'm currently thinking about alternative ways of making connections on
> a modular synth, particularly of the primitive, somewhat random kind.
> For example, German Synthi AKS improviser Thomas Lehn sticks bits of
> metal in the Synthi "Prestopatch" slot and wiggles it around, to
> short-circuit between various modules and make all kinds of sudden
> complex noises...This is what I'm into as well. (It doesn't seem to
> harm his Synthi, by the way).
>
> I'd love to hear about other ways that people are "mechanically"
> interfacing with their synths. I vaguely remember seeing some design
> that just had a number of metal nails sticking up, for example, that
> one would either touch or clamp crocodile cables to.
> I also seem to remember something with a metal ball rolling around
> another bed of nails?
>
> Sorry to jump from lurking to taking up so much bandwidth all of a
> sudden, by the way...
>
> Thank you for any hints, suggestions etc!
>
> Alex
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From psilord at cs.wisc.edu  Mon Apr  7 21:23:13 2008
From: psilord at cs.wisc.edu (Peter Keller)
Date: Mon, 7 Apr 2008 14:23:13 -0500
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
Message-ID: <20080407192312.GA8093@cs.wisc.edu>

On Mon, Apr 07, 2008 at 08:24:59PM +0200, |||||||||| |||||||||| wrote:
> I'd love to hear about other ways that people are "mechanically"
> interfacing with their synths. I vaguely remember seeing some design
> that just had a number of metal nails sticking up, for example, that
> one would either touch or clamp crocodile cables to.
> I also seem to remember something with a metal ball rolling around
> another bed of nails?

Having just made up this method and never tried it, how about this:

Make a 2D nail board with the tips precisely vertically aligned and
suspend it over salt water where the tips are *almost* touching the water.
The nail tip have to be high enough though that surface tension doesn't
leave a connection from the nails to the water.

It would look like this (~ is water):

| _____________________________________________ |
| ||||||||||||||||||||||||||||||||||||||||||||| |
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
-------------------------------------------------

Then, produce waves in the water box. The crests of the waves and of the
constructive interference will produce interesting patterns of electrical
connection.

You could drive longer non electrically connected nails through the nail board
and into the water that when you hit with a mallet, produce the waves at
different 2D points in the water box. That would look like this:

|                                               |
| |___|___|___|___|___|___|___|___|___|___|___| |
| ||||||||||||||||||||||||||||||||||||||||||||| |
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
-------------------------------------------------

Then, hitting the nails could produce more interesting repeatable wave
interference patters much better than hitting the box would.

The above is a linear version of the system, a full system would be
fully 2D.

Later,
-pete



From grichter at asapnet.net  Mon Apr  7 21:57:09 2008
From: grichter at asapnet.net (Grant Richter)
Date: Mon, 7 Apr 2008 14:57:09 -0500
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <20080407192312.GA8093@cs.wisc.edu>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
Message-ID: <3BF1364E-0DB1-473B-8F14-CE1F7DD0E24E@asapnet.net>

I cooked up this little home made Vactrol thing that is good for  
overlaying patches on top of one another.
It is the only module I know of that is designed to vary the  
resistance of the patch connections themselves.

Instructions are here:

http://www.musicsynthesizer.com/Hairball/hairball.html



From blincoln at eventualdecline.com  Mon Apr  7 22:00:04 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 7 Apr 2008 13:00:04 -0700 (PDT)
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <20080407192312.GA8093@cs.wisc.edu>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
Message-ID: <59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>

That's a pretty cool idea. Could you do something similar using ferrofluid
(so that the shape of the fluid could be magnetically controlled as well
as vibrationally), or would the electromagnets and whatnot cause too much
interference?

On Mon, April 7, 2008 12:23 pm, Peter Keller said:

> Having just made up this method and never tried it, how about this:
>
> Make a 2D nail board with the tips precisely vertically aligned and
> suspend it over salt water where the tips are *almost* touching the water.
> The nail tip have to be high enough though that surface tension doesn't
> leave a connection from the nails to the water.
>
> It would look like this (~ is water):
>
> | _____________________________________________ |
> | ||||||||||||||||||||||||||||||||||||||||||||| |
> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
> -------------------------------------------------
>
> Then, produce waves in the water box. The crests of the waves and of the
> constructive interference will produce interesting patterns of electrical
> connection.
>
> You could drive longer non electrically connected nails through the nail
> board
> and into the water that when you hit with a mallet, produce the waves at
> different 2D points in the water box. That would look like this:
>
> |                                               |
> | |___|___|___|___|___|___|___|___|___|___|___| |
> | ||||||||||||||||||||||||||||||||||||||||||||| |
> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
> -------------------------------------------------
>
> Then, hitting the nails could produce more interesting repeatable wave
> interference patters much better than hitting the box would.
>
> The above is a linear version of the system, a full system would be
> fully 2D.




From Peter.Ullrich at kapsch.net  Mon Apr  7 22:09:00 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 7 Apr 2008 22:09:00 +0200
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
References: <47FA2167.5050606@eventualdecline.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>,
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B0C@S060VS20.kapsch.co.at>


Hi Batz!

>If you take a look at the photos on that site I posted, you'll notice that
>the only ICs adjacent to the VCA chip are a couple of Op Amp packages. A
>TL074 and some kind of 8 pin device. (Might even be a dual sample/hold
>chip) Each channel seems to be accompanied by a pair of trim pots. I can't
>see anything that suggests any further switching components per channel.
>Which is what threw me about the extra jacks. I would have expected there
>to be some kind of switching on the Mo-Bo but there was none.

I don't think that there some switching elements. Switching off the channels is
simply done via the VCAs that are good enough for this job.

>So all I can glean from these photos is that it's got MIDI and RS232. It
>also seems to have SMPTE I/O of some kind. And is powered by a HC11.

Yes, as far as I remember this little beast normally works synchronzed via SMPTE.
But you can also use it without (unsync'ed) via starting the software clock on the PC program.

>I need to make a decision whether to make a play for this thing within the
>next day or two. I know I could sum the outputs fairly easily. But I guess
>now it seems I have to find some kind of special software to run it.

I can give you the original Behringer software... Different version.
Should run up to WinME but with additional tools it should also run on Win2000
and WinXP but I haven't tried that yet. But I could test it in a few days when I have
more time (hopefully).

>At it's most basic, I just need to mix a bunch of incoming stereo sources
>from Analogue synths etc. Each synth has it's own autonomous mix/FX chain.
>The only thing I need to do is adjust each synth's level to normalize them.

Should be no problem.

>But if I could also use it like an automated noise gate, where I only have
>to have them in line as needed, then that would be a bonus. This is where
>this behringer box and it's VCAs would come in.

Also for that it should be OK - maybe a bit "overshot".
A few years ago I built a 48 channel MIDI-MUTE automation for a medium studio
mixer and the mute circuit was very primitve but worked fine. We added the circuit directly
into the mixer and swithced the audio signal right before the summing resistor (when I remeber
correctly) via a simple MOSFET to GND. I think we used the BSS98 MOSFETs.

They did not disturb or make noise when open but grounded the signal line so that no
further noise came to the summing line. I controlled this mute circuit via MIDI that was analyzed
by an 8051 microcontroller that controlled the MOSFETs via 8255 IO circuits (24 lines per chip).
This system worked very nice and could be upgraded to a lot more channels. You just have
to think how you will control it via MIDI. I controlled it via MIDI note on/off commands...

>I've tried various methods of doing this in the past but none of them have
>been quiet enough. OTAs are too noisy outright. The digital control blocks
>have zipper noise. Just plain switching causes pops and sudden introduction
>of noise. And to build something like this from scratch would be both
>prohibitively expensive and time consuming. And there-in lies the rub.

If you want to use it a realtime noise gate that switched during your music than my solution is not
perfect - but with an addition we added later (RC filter for soft switching) it was also useable.
The main task for this tools was to make unused mixer channels silent. So if the parts of that
channel ended we sent MIDI note off for that channel ansd it was muted until the next
signal should come - then we switched on via MIDI note on again.

>I don't want to find myself having to learn and write HC11 code.Or any code
>for that matter. I now just need to know that I can slot it in with some
>mods and tell it to behave and it will. So I'm a bit concerned about this
>RS232 notion and getting whatever software is required. More to the point,
>that means it's not platform independent and likely to become redundant.

So you could only use the Behringer software.
If you could write a program then the analysation of the serial data stream would be possible.
I have done this for some gadgets in the past but not for the CM8000...

>But from the general consensus here it seems like it's worth making a play
>for. And If so, I'll take you up on that offer Peter. You can always use my
>FTP and I'm happy to host some files there if anyone else needs this stuff.

Give me your FTP access data and I will upload the files.
It would be nice if other users could have read access too.

Ciao
Peter

http://www.ullrich.at.tt



From psilord at cs.wisc.edu  Mon Apr  7 22:16:56 2008
From: psilord at cs.wisc.edu (Peter Keller)
Date: Mon, 7 Apr 2008 15:16:56 -0500
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
	<59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
Message-ID: <20080407201655.GA10006@cs.wisc.edu>

On Mon, Apr 07, 2008 at 01:00:04PM -0700, Ben Lincoln wrote:
> That's a pretty cool idea. Could you do something similar using ferrofluid
> (so that the shape of the fluid could be magnetically controlled as well
> as vibrationally), or would the electromagnets and whatnot cause too much
> interference?

I see... You'd place magnets on the surface of the board, which would pull
the ferrofluid up to the nails for contact. This method would produce
probably very stable "patches", meaning you place the various magnets
around the 2D board and each would pull up the fluid to it (and have some
sticky-ball like behaviour when the magnets are close to each other).

I think your magnetic control method would produce localized connections
easily and since there really isn't enough of a changing magnetic field
interacting with the nails (only when you move the magnets), I think it
would be electrically stable.

One problem would be the nails themselves would act as flux intensifiers,
so you'd either get a complicated field (read, a large patch of connected
nails), or would have to use plastic nails with a conductive tip to
minimize the effect.

Vibrational control means putting some servos around the water box
(sides and bottom), and then controlling the vibration of the water
(or more viscous substance). Here's a video of such a thing:

http://www.c00lstuff.com/178/Non_Newtonian_fluid_under_vibration/

I'm sure there are better videos, but I'm in a hurry.

But, if you want to keep the human aspect of patch/music generation with
this system we've informally described, then either the mallets on the nails
for music generation, or ferromagetic fluid and magnets for patch generation
seem to be a good idea. Just my 2 cents though...

Later,
-pete


From tensiontype at hotmail.com  Mon Apr  7 22:26:35 2008
From: tensiontype at hotmail.com (Sean Ellis)
Date: Mon, 7 Apr 2008 22:26:35 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
Message-ID: <BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>

Once I got a very small bowl of water and experimented with dipping patch 
cables into it to see the resistance. The goal was to make some sort of 
illuminated rotating lfo with water splashing around :) It worked OK but 
needed a tiny amount of water or the resistance was too great.

----- Original Message ----- 
From: "Peter Keller" <psilord at cs.wisc.edu>
To: "|||||||||| ||||||||||" <beschaving at gmail.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 07, 2008 9:23 PM
Subject: Re: [sdiy] Chaotic/lo-fi patching techniques


> On Mon, Apr 07, 2008 at 08:24:59PM +0200, |||||||||| |||||||||| wrote:
>> I'd love to hear about other ways that people are "mechanically"
>> interfacing with their synths. I vaguely remember seeing some design
>> that just had a number of metal nails sticking up, for example, that
>> one would either touch or clamp crocodile cables to.
>> I also seem to remember something with a metal ball rolling around
>> another bed of nails?
>
> Having just made up this method and never tried it, how about this:
>
> Make a 2D nail board with the tips precisely vertically aligned and
> suspend it over salt water where the tips are *almost* touching the water.
> The nail tip have to be high enough though that surface tension doesn't
> leave a connection from the nails to the water.
>
> It would look like this (~ is water):
>
> | _____________________________________________ |
> | ||||||||||||||||||||||||||||||||||||||||||||| |
> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
> -------------------------------------------------
>
> Then, produce waves in the water box. The crests of the waves and of the
> constructive interference will produce interesting patterns of electrical
> connection.
>
> You could drive longer non electrically connected nails through the nail 
> board
> and into the water that when you hit with a mallet, produce the waves at
> different 2D points in the water box. That would look like this:
>
> |                                               |
> | |___|___|___|___|___|___|___|___|___|___|___| |
> | ||||||||||||||||||||||||||||||||||||||||||||| |
> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
> -------------------------------------------------
>
> Then, hitting the nails could produce more interesting repeatable wave
> interference patters much better than hitting the box would.
>
> The above is a linear version of the system, a full system would be
> fully 2D.
>
> Later,
> -pete
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From ebrombaugh at earthlink.net  Mon Apr  7 22:35:42 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Mon, 07 Apr 2008 13:35:42 -0700
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <20080407201655.GA10006@cs.wisc.edu>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>	<20080407192312.GA8093@cs.wisc.edu>	<59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
	<20080407201655.GA10006@cs.wisc.edu>
Message-ID: <47FA859E.9000505@earthlink.net>

Peter Keller wrote:
> On Mon, Apr 07, 2008 at 01:00:04PM -0700, Ben Lincoln wrote:
>> That's a pretty cool idea. Could you do something similar using ferrofluid
>> (so that the shape of the fluid could be magnetically controlled as well
>> as vibrationally), or would the electromagnets and whatnot cause too much
>> interference?
> 
> I see... You'd place magnets on the surface of the board, which would pull
> the ferrofluid up to the nails for contact. This method would produce
> probably very stable "patches", meaning you place the various magnets
> around the 2D board and each would pull up the fluid to it (and have some
> sticky-ball like behaviour when the magnets are close to each other).

For a more integrated approach, how about using one of these:

http://www.analog.com/en/prod/0%2C2877%2CAD8113%2C00.html

AD8113 16x16 crosspoint switch with a SPI input for controlling the 
selections. Just hook up your favorite microcontroller to randomly 
generate switch configurations. Main downside is that you can't drive 
one output with multiple inputs - it's a 1:1 hookup only. Might not be 
quite as whacky as what randomly shorting outputs together will do...

Eric


From Peter.Ullrich at kapsch.net  Mon Apr  7 22:54:19 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 7 Apr 2008 22:54:19 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <47FA859E.9000505@earthlink.net>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
	<59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
	<20080407201655.GA10006@cs.wisc.edu>,<47FA859E.9000505@earthlink.net>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B0F@S060VS20.kapsch.co.at>


Hi!

>For a more integrated approach, how about using one of these:
>
>http://www.analog.com/en/prod/0%2C2877%2CAD8113%2C00.html
>
>AD8113 16x16 crosspoint switch with a SPI input for controlling the
>selections. Just hook up your favorite microcontroller to randomly
>generate switch configurations. Main downside is that you can't drive
>one output with multiple inputs - it's a 1:1 hookup only. Might not be
>quite as whacky as what randomly shorting outputs together will do...

You can simply turn it into a mixer by adding summing resistors on the
inputs and adding inverting opamps on the outputs.
So each output of the matrix is the summing point of the summing amp
made with the inverting opamp on the output.

Works fine - I built this with the Mitel/Zarlink MT8816 and also with
the MT8812 parts.

The can be used for static signals, MIDI, Audio and up to video signals.

I also used this parts fpr universal MIDI interfaces where these matrix
circuits sit in parallel with the keyboard matrix. Not a cheap solution as
you need I think 4 of the MT8816 because you have to add decoupling
diodes. But for me it was OK because I had a few dozen of these chips...
My Korg Poly61 MIDI interface works with these chips...

For the Casio SK1 I used the MT8812 chip but without the complete
decoupling - so the polyphony via the MIDI interface is limited to 2.
One year after I built it I found a nicer solution someone built where a
microcontroller scanned the keyboard rows and generated the column
signals at the right moment to simulte a keypress. This solution need no
decoupling diodes but has full polyphony...

Ciao
Peter

http://www.ullrich.at.tt



From Peter.Ullrich at kapsch.net  Mon Apr  7 22:55:53 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 7 Apr 2008 22:55:53 +0200
Subject: AW: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <47FA859E.9000505@earthlink.net>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
	<59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
	<20080407201655.GA10006@cs.wisc.edu>,<47FA859E.9000505@earthlink.net>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B10@S060VS20.kapsch.co.at>


Hi again!

Sorry I have seen that the AD8113 have internal buffers... so the
summing option is not available for this part...

So you might have a look at the Mitel/Zarlink MT8816 or similar.

The datasheet can be found here:
http://www.datasheetarchive.com  and enter MT8816
You can load the old Mitel and the newer Zarlink datasheet.

Ciao
Peter

http://www.ullrich.at.tt



From Peter.Ullrich at kapsch.net  Mon Apr  7 23:02:21 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 7 Apr 2008 23:02:21 +0200
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
References: <47FA2167.5050606@eventualdecline.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>,
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B0D@S060VS20.kapsch.co.at>


Hi!

While searching on Google I found that Behringer still has the software Online.
You can load it from here:

http://www.behringer.com/MX8000A/index.cfm?lang=ENG

and then click on editor software...

Ciao
Peter



From psilord at cs.wisc.edu  Mon Apr  7 23:03:53 2008
From: psilord at cs.wisc.edu (Peter Keller)
Date: Mon, 7 Apr 2008 16:03:53 -0500
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <47FA859E.9000505@earthlink.net>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
	<59226.38.112.225.84.1207598404.squirrel@www.eventualdecline.com>
	<20080407201655.GA10006@cs.wisc.edu>
	<47FA859E.9000505@earthlink.net>
Message-ID: <20080407210352.GA11403@cs.wisc.edu>

On Mon, Apr 07, 2008 at 01:35:42PM -0700, Eric Brombaugh wrote:
> AD8113 16x16 crosspoint switch with a SPI input for controlling the 
> selections. Just hook up your favorite microcontroller to randomly 
> generate switch configurations.

Instead of random, you could do a GA type approach. Have the computer
pick 10 random connection matricies (meaning 10 different connections
of patches), you listen to a 440Hz through each one, pick two you like,
then do it again. Keep going until you find something you really like,
or start over. In the end, have the computer emit a human readable
patch descrption.

-pete


From neil.johnson97 at ntlworld.com  Mon Apr  7 23:11:21 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Mon, 7 Apr 2008 22:11:21 +0100
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
Message-ID: <F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>

Hi,

> I'd love to hear about other ways that people are "mechanically"
> interfacing with their synths. I vaguely remember seeing some design
> that just had a number of metal nails sticking up, for example, that
> one would either touch or clamp crocodile cables to.

Something like this?:

http://gallery.diy.synth.net/main.php?g2_itemId=868

Yes, it was quite a strange box.  The schematic, too, was, umm,  
artistic.

Neil
--
http://www.njohnson.co.uk





From controlvoltage at gmail.com  Mon Apr  7 23:37:00 2008
From: controlvoltage at gmail.com (Amos)
Date: Mon, 7 Apr 2008 17:37:00 -0400
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
Message-ID: <908a4c120804071437v4b227b0fxba7257e334d52cc2@mail.gmail.com>

On Mon, Apr 7, 2008 at 5:11 PM, Neil Johnson
<neil.johnson97 at ntlworld.com> wrote:
> > I vaguely remember seeing some design
> > that just had a number of metal nails sticking up, for example, that
> > one would either touch or clamp crocodile cables to.
> >
>
>  Something like this?:
>
>  http://gallery.diy.synth.net/main.php?g2_itemId=868
>
>  Yes, it was quite a strange box.  The schematic, too, was, umm, artistic.

Reminds me of the infamous "din datin dudero," a DIY patchable analog
synth programmed with... live earthworms. yep.
http://musicthing.blogspot.com/2005/03/diy-worm-powered-synth.html


From djhohum at gmail.com  Tue Apr  8 01:02:21 2008
From: djhohum at gmail.com (Jim Panci)
Date: Mon, 7 Apr 2008 16:02:21 -0700
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <908a4c120804071437v4b227b0fxba7257e334d52cc2@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
	<908a4c120804071437v4b227b0fxba7257e334d52cc2@mail.gmail.com>
Message-ID: <e11030040804071602r6a27c663r538f81ab66554e19@mail.gmail.com>

It seems one could take the bed of nails and the worm ideas and
combine them with a slightly less sadistic approach. The performer
could lie on the bed of nails himself as the ultimate expression of
randomness meets dedication to art. The more blood that flows the
better the contacts, hence, the more intense the sound (presuming
correct design, of course). The truly dedicated will not mess around
with wimpy solid state synths but will go straight to custom modified
tube gear. Gives new meaning to the phrases "wretch machine" and
"performance pressure"!

Alternately, one could just employ a voltage controlled power supply.
Control of output voltage and current limit should be easy. You could
control the plus and minus rails separately for asymmetric sorts of
effects. For a real challenge you could create a voltage controlled
capacitor out of between 8 to 12 relays, a similar number of caps with
value approx 2^n * smallest cap, and a suitable A to D chip to give
you voltage controllable filtering.


On 4/7/08, Amos <controlvoltage at gmail.com> wrote:
> On Mon, Apr 7, 2008 at 5:11 PM, Neil Johnson
>  <neil.johnson97 at ntlworld.com> wrote:
>  > > I vaguely remember seeing some design
>  > > that just had a number of metal nails sticking up, for example, that
>  > > one would either touch or clamp crocodile cables to.
>  > >
>  >
>  >  Something like this?:
>  >
>  >  http://gallery.diy.synth.net/main.php?g2_itemId=868
>  >
>  >  Yes, it was quite a strange box.  The schematic, too, was, umm, artistic.
>
>
> Reminds me of the infamous "din datin dudero," a DIY patchable analog
>  synth programmed with... live earthworms. yep.
>  http://musicthing.blogspot.com/2005/03/diy-worm-powered-synth.html
>
> _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From samppa.tolvanen at gmail.com  Tue Apr  8 01:56:49 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 8 Apr 2008 02:56:49 +0300
Subject: [sdiy] alternatives to d-sub?
In-Reply-To: <7790ca750804070119l4cf14a7bk613fca357f3a1a1e@mail.gmail.com>
References: <5943766.1207525736578.JavaMail.root@mswamui-billy.atl.sa.earthlink.net>
	<47F9CD03.406@eventualdecline.com>
	<7790ca750804070119l4cf14a7bk613fca357f3a1a1e@mail.gmail.com>
Message-ID: <fa1b0bd80804071656x650b7467t484008ee93e1b473@mail.gmail.com>

On 4/7/08, synth junk <synthjunk at gmail.com> wrote:
> Jones (Cinch Jones) connectors can be  used for such applications.
>
>  http://www.cinch.com/view_product_line.cinch?id=29
>
>  They make them with up to 33 connectors. They're not "high tech" but
>  they're easy to work with.
>
>  david
>

I've taken some cables with Cinch Jones plugs from Hospital
renovations dumpster - non shielded cables (damn). I doubt the
connectors aren't "that bad", only EMS users.. ;)


From samppa.tolvanen at gmail.com  Tue Apr  8 02:24:34 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 8 Apr 2008 03:24:34 +0300
Subject: [sdiy] Using shielded cable with banana plugs?
In-Reply-To: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
References: <de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
Message-ID: <fa1b0bd80804071724h52093e3fk481da3370751ad14@mail.gmail.com>

Well,

not intended to offend _anybody_, especially Buchla or Serge users.

But: "Bananas are for the Monkeys":

http://www.gainomax.com/monkey/

Samppa

p.s. Other than some Swedish users can user their Brain for the Recovery :)


From guitaricon at comcast.net  Tue Apr  8 03:23:42 2008
From: guitaricon at comcast.net (jeff brown)
Date: Mon, 7 Apr 2008 21:23:42 -0400
Subject: [sdiy] New R. Rich MOTM CD/website
References: <008101c8951e$b28a6170$b000a8c0@curley>
Message-ID: <000f01c89917$2f160950$0302a8c0@jeff>

Thanks for the link.

Nice website.  I ordered "React" and "Electric Ladder" and got them today - 
autographed and $2 cheaper than Amazon to boot!

Good stuff.

Cheers,
Jeff

----- Original Message ----- 
From: "Paul Schreiber" <synth1 at airmail.net>
To: "Synth-DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 02, 2008 8:07 PM
Subject: [sdiy] New R. Rich MOTM CD/website


>> www.robertrich.com new website, lots of analog synth audio tracks
>>
>> New live recording "React" featuring Ian Boddy (UK DiN Records). MOTM 
>> analog modular featured.
>>
>> Paul S.
>>
>>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From derek at umatic.nl  Tue Apr  8 10:43:39 2008
From: derek at umatic.nl (Derek Holzer)
Date: Tue, 08 Apr 2008 10:43:39 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
Message-ID: <47FB303B.9000700@umatic.nl>

Hi Alex,

I've also seen Cor Fuhler (http://www.euronet.nl/users//fuhler/) play 
his Synthi EMS with things like a stove-lighter over the lid-keyboard 
(the sparks seem to trigger the keys as well as pressure) and a 
"randomizer" attached to the patchbay, which is basically a wheel which 
makes and breaks various pin connections.

The work of circuit-bender and "shyinths" designer Peter Blesser uses 
quite a bit of crocodile clipping across nail patchbays and spoons stuck 
in the mouth:

http://www.ciat-lonbarde.net/shinths/index.html

But my feeling is that these kind of "noisy" or "random" approaches 
might be a bit less popular in this list, which seems to strive for more 
"perfect" or "musical" results. But that's just my feeling. I'm at an 
internet cafe right now, so I haven't scanned the rest of this thread, 
but I'm looking forward once I'm not paying for every second online ;-)

My own DIY project, TONEWHEELS, uses phototransistors modulated by 
spinning transparent disks in an overhead projector to make a very 
mechanical audiovisual set. I send the voltage straight to the mixer as 
audio (after some buffering action), or use it as CV in my Doepfer/DIY 
modular:

http://umatic.nl/tonewheels.html

Maybe I'll think of some more after reading this thread.

best!
d.

|||||||||| |||||||||| wrote:
> Hi everyone,
> 
> I'm currently thinking about alternative ways of making connections on
> a modular synth, particularly of the primitive, somewhat random kind.
> For example, German Synthi AKS improviser Thomas Lehn sticks bits of
> metal in the Synthi "Prestopatch" slot and wiggles it around, to
> short-circuit between various modules and make all kinds of sudden
> complex noises...This is what I'm into as well. (It doesn't seem to
> harm his Synthi, by the way).
> 
> I'd love to hear about other ways that people are "mechanically"
> interfacing with their synths. I vaguely remember seeing some design
> that just had a number of metal nails sticking up, for example, that
> one would either touch or clamp crocodile cables to.
> I also seem to remember something with a metal ball rolling around
> another bed of nails?

-- 
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 111:
"Lowest common denominator check
-single beat
-single note
-single riff"


From batzman-nr at all-electric.com  Tue Apr  8 10:54:50 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Tue, 08 Apr 2008 18:24:50 +0930
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <66989A9506070B43A3B606F3009CB90A3B704E8B0C@S060VS20.kapsch
	.co.at>
References: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
Message-ID: <5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>

Y-ellow All.
         Thanks once again. And I downloaded that software. Haven't had a 
look at it yet.

Here's a question I guess better formulated. In amongst any of the lit that 
comes with this thing, is there a run down of the RS232 control messages 
and the MIDI messages that this thing understands?

Under linux it would be snap to write a bit of perl or even shell grit to 
send out the required RS232 messages. MIDI of course would make it more 
universal.

I had thought about something similar to your FET system Peter. Even the 
use of an RC time constant so it ramped in/out rather than thumped. I've 
messed with similar schemes using bipolars. And noted that both Korg and 
Yamaha make extensive use of these kinds of schemes. Although only Korg 
were so cut-price to actually use them in place of an actual VCA in a 
synth. If I were in the mood for coding up a micro I'd probably do 
something along those lines. Either an 8255 or just an MCS51 derivative 
with lots of I/O pins. And probably use a 2N3819 since I've managed to 
acquire a quantity.

What can I say though. The flesh is willing by the mind is weak.

My FTP site is. ftp://all-electric.com/incoming But while we're speaking of 
FTPs, if you look in the "video" directory you'll find a copy of our 
"Persecutor 3000" animation which Dr. Badger and I did last year for the 
denialism blog. But it's also up on SpewTube now I believe.

A warning though. If your favorite Genius is Ted Haggard rather than 
Richard Dawkins, you probably won't like this. :)

Thanks again.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From admin at bugbrand.co.uk  Tue Apr  8 11:24:13 2008
From: admin at bugbrand.co.uk (Tom Bugs)
Date: Tue, 08 Apr 2008 10:24:13 +0100
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>	<20080407192312.GA8093@cs.wisc.edu>
	<BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
Message-ID: <47FB39BD.2010906@bugbrand.co.uk>

Licked fingers (or maybe just sweaty) or other body parts (ooo-er) will 
provide much higher resistances! --- earthworms are exactly the same 
idea, but isn't it a bit cruel?
-- you can make a patchbay kind of like a cracklebox touchplate -- this 
can be great fun to play.

Needless to say - be careful and aware of what you're doing both for 
your own health and that of your synth. I've not had any problems 
myself, but I've certainly felt some electrical flow when I've held 
patch cables in my mouth!



Sean Ellis wrote:
> Once I got a very small bowl of water and experimented with dipping 
> patch cables into it to see the resistance. The goal was to make some 
> sort of illuminated rotating lfo with water splashing around :) It 
> worked OK but needed a tiny amount of water or the resistance was too 
> great.
>
> ----- Original Message ----- From: "Peter Keller" <psilord at cs.wisc.edu>
> To: "|||||||||| ||||||||||" <beschaving at gmail.com>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Monday, April 07, 2008 9:23 PM
> Subject: Re: [sdiy] Chaotic/lo-fi patching techniques
>
>
>> On Mon, Apr 07, 2008 at 08:24:59PM +0200, |||||||||| |||||||||| wrote:
>>> I'd love to hear about other ways that people are "mechanically"
>>> interfacing with their synths. I vaguely remember seeing some design
>>> that just had a number of metal nails sticking up, for example, that
>>> one would either touch or clamp crocodile cables to.
>>> I also seem to remember something with a metal ball rolling around
>>> another bed of nails?
>>
>> Having just made up this method and never tried it, how about this:
>>
>> Make a 2D nail board with the tips precisely vertically aligned and
>> suspend it over salt water where the tips are *almost* touching the 
>> water.
>> The nail tip have to be high enough though that surface tension doesn't
>> leave a connection from the nails to the water.
>>
>> It would look like this (~ is water):
>>
>> | _____________________________________________ |
>> | ||||||||||||||||||||||||||||||||||||||||||||| |
>> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
>> -------------------------------------------------
>>
>> Then, produce waves in the water box. The crests of the waves and of the
>> constructive interference will produce interesting patterns of 
>> electrical
>> connection.
>>
>> You could drive longer non electrically connected nails through the 
>> nail board
>> and into the water that when you hit with a mallet, produce the waves at
>> different 2D points in the water box. That would look like this:
>>
>> |                                               |
>> | |___|___|___|___|___|___|___|___|___|___|___| |
>> | ||||||||||||||||||||||||||||||||||||||||||||| |
>> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
>> -------------------------------------------------
>>
>> Then, hitting the nails could produce more interesting repeatable wave
>> interference patters much better than hitting the box would.
>>
>> The above is a linear version of the system, a full system would be
>> fully 2D.
>>
>> Later,
>> -pete
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>



From derek at umatic.nl  Tue Apr  8 11:50:32 2008
From: derek at umatic.nl (Derek Holzer)
Date: Tue, 08 Apr 2008 11:50:32 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>	<20080407192312.GA8093@cs.wisc.edu>
	<BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
Message-ID: <47FB3FE8.7090305@umatic.nl>

At Pickled Feet (http://pickledfeet.com/workshops.php) we've done stuff 
with using homemade dielectric caps (i.e. two pieces of tinfoil with 
paper in between, or a film can filled with saltwater and copper tape 
around the outside) as well as petri dishes filled with gelatin as a 
resistor, or graphite on paper. Usually these are connected to a simple 
Schmidt trigger oscillator. This can become very performative. Alligator 
clips are always your friend...

d.

Sean Ellis wrote:
> Once I got a very small bowl of water and experimented with dipping 
> patch cables into it to see the resistance. The goal was to make some 
> sort of illuminated rotating lfo with water splashing around :) It 
> worked OK but needed a tiny amount of water or the resistance was too 
> great.


-- 
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 125:
"Only a part, not the whole"


From derek at umatic.nl  Tue Apr  8 11:55:21 2008
From: derek at umatic.nl (Derek Holzer)
Date: Tue, 08 Apr 2008 11:55:21 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
Message-ID: <47FB4109.7020604@umatic.nl>

Yes, this is Peter Blesser's work:

http://www.ciat-lonbarde.net/

This kind of electro-mystic freakery is sometimes (but not always) a 
welcome break from clean engineering, reminds you that the process is 
also the artwork.

best,
d.

Neil Johnson wrote:

> Something like this?:
> 
> http://gallery.diy.synth.net/main.php?g2_itemId=868
> 
> Yes, it was quite a strange box.  The schematic, too, was, umm, artistic.


-- 
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy #62:
"Don't be frightened to display your talents"


From Peter.Ullrich at kapsch.net  Tue Apr  8 13:50:21 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Tue, 8 Apr 2008 13:50:21 +0200
Subject: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
References: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<de53b7a90804060943j56ea6c06i4ae432807ec652f1@mail.gmail.com>
	<5.1.0.14.2.20080407173652.04449008@mail.all-electric.com>
	<47FA2167.5050606@eventualdecline.com>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>


Hi Batz!

>Here's a question I guess better formulated. In amongst any of the lit
>that comes with this thing, is there a run down of the RS232 control
>messages and the MIDI messages that this thing understands?

Sorry, the interface specification/message are not documented in the
Behringer manual. And I had not time to analyze the data stream yet.

>Under linux it would be snap to write a bit of perl or even shell
>grit to send out the required RS232 messages.

Would be no problem regardless of the programming language - serial
Messages are esay to program - even under Basic...

>MIDI of course would make it more universal.

I don't know if it is possible via MIDI. MIDI is only mentioned for
MIDI time code (MTC) purposes...
So I think that volume settings are only possible via the serial
interface (working at 19200 Baud).

>My FTP site is. ftp://all-electric.com/incoming
>But while we're speaking of FTPs, if you look in the "video"
>directory you'll find a copy of our "Persecutor 3000" animation
>which Dr. Badger and I did last year for the denialism blog.
>But it's also up on SpewTube now I believe.

Sorry but I have no rights to get there. No problem reaching your root
Directory and video directory but permission is denied on the incoming
Directory.

>A warning though. If your favorite Genius is Ted Haggard rather
>than Richard Dawkins, you probably won't like this. :)

I don't know both of them :-O

Ciao
Peter

http://www.ullrich.at.tt



From jpdesroc at oricom.ca  Tue Apr  8 14:31:35 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Tue, 8 Apr 2008 08:31:35 -0400
Subject: [sdiy] 1Meg log taper pot for ADSR module..
Message-ID: <380-22008428123135273@oricom.ca>

Hi list,

Here is my question:
I'm building a DIY modular synth using the same type of
Front panels Moog system 55 uses. Now I'm working on
the Envelope Generator module like the 911, I'm drafting the
front panel and would like to use the same
graphics (2msec. To 10sec. ) the 911 module used
for the T1, T2, T3 (Attack, Decay, Release) time potentiometers.
See picture:
http://idecibel.tuxfamily.org/moog900/911.jpg
I'd like to know what is the Brand/model of the 1meg
potentiometer Moog used for adjusting these time durations.
The 911 module T1, T2, T3  pots panel graphics are precises from
2msec to 10sec
(are they really?) Most of the 1meg log pots I found
on the market are +-20% for "1meg and more" values..
The closest pot type I found would be the 
Precision Electronics Components KA1051S28 1meg log.
The Alpha Brand 24mm 1meg log pots I tried
(bought at Mouser.com) are way out 
of the graphical msec/sec front panel marks
(the log curve is not accurate)..

Your help and advices are appreciated.
J-Pierre Desrochers




From djservs at comcast.net  Tue Apr  8 15:13:52 2008
From: djservs at comcast.net (Nate Reeves)
Date: Tue, 8 Apr 2008 09:13:52 -0400
Subject: [sdiy] tbDAC-2 midi-CV Convertor
Message-ID: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>

anyone have one for sale, just hte PCB or even a completed one?
i want to get MIDI on the 3031
cheers
nate



From daugard at sprintmail.com  Tue Apr  8 15:42:53 2008
From: daugard at sprintmail.com (Tim Daugard)
Date: Tue, 8 Apr 2008 08:42:53 -0500
Subject: [sdiy] Chaotic/lo-fi patching techniques
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<20080407192312.GA8093@cs.wisc.edu>
Message-ID: <001701c8997e$72b8c5a0$2d8bfe04@tim3>

From: "Peter Keller" <psilord at cs.wisc.edu>

> Then, produce waves in the water box. The crests of the waves and of the
> constructive interference will produce interesting patterns of electrical
> connection.

Hmm, if we add layer of oil, some dyes, an over head projector and we have a sound and
light show!

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
http://home.sprintmail.com/~daugard/synth.htm
http://home.earthlink.net/~synthfred/h_toctop.htm (Fred's online edition)





From techman at synth.net  Tue Apr  8 17:20:37 2008
From: techman at synth.net (Andy Wilson)
Date: Tue, 08 Apr 2008 16:20:37 +0100
Subject: [sdiy] tbDAC-2 midi-CV Convertor
In-Reply-To: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
Message-ID: <47FB9B55.6152.195439E@techman.synth.net>

I used Trevor Pages's RX303 Midi/CV convertor for my 3031

http://www.techman.synth.net/techman_website2_000029.htm

details in the Files section of the Introspectiv Yahoo group

regards

Andy


On 8 Apr 2008 at 9:13, Nate Reeves wrote:

> anyone have one for sale, just hte PCB or even a completed one?
> i want to get MIDI on the 3031
> cheers
> nate
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


---

Andy Wilson
www.techman.synth.net
techman at synth.net



From aankrom at bluemarble.net  Tue Apr  8 19:32:36 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 8 Apr 2008 13:32:36 -0400
Subject: [sdiy] how to fix a blinking/blank neon power indicator?
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
	<47FB9B55.6152.195439E@techman.synth.net>
Message-ID: <00ca01c8999e$8b6f7880$0202a8c0@positronium>

Anybody know why sometimes just out of the blue, a neon bulb will stop 
working or begin to blink intermittantly?

My guess is that there wasn't an adequate current-limiting resistor and the 
gap betwwen the electrodes widened. This would seem to explain the blinking 
ones too: the gap hasn't widened enough to keep it from firing, but it has 
to wait for enough charge to build to "jump" across.

I've also noticed that heavy inductive loads, say a variac controlling a 
1000 watt heating element, can cause the neon bulb to go out if the setup is 
(unwisely) connected to a power strip that has a neon power indicator (the 
one I was using didn't have a surge protector so it wasn't anything to do 
with that...). But I don't know what this is about unless it somehow causes 
a voltage drop locally across the system. But it couldn't have to the 
electrical system to the whole building in a modern university.

So I had an idea to "fix" a failing bulb: connecting something like a 
polypropylene X2 rated capacitor across the neon bulb leads. I haven't tried 
this yet: I was wondering if it'd work. I have a HUGE collection of a wide 
range of MKP X2 caps taken from various power supplies.

So does anyone think this'd work?  If so what would be a good capacitance 
rating? Is there a better fix? I'd just replace the bulb, but it is a row of 
switches with the neon bulbs right inside them and these is a number of them 
that do not work. Would something like an oil-filled motor-start cap work 
better? I have a 3.5uF one rated for 450VAC and a 0.5uF one rated for 
2500VAC (probably too small: might as well use a MPK X2...). Or a 10uF, 
160VAC metallized paper motor-start cap maybe?

And gosh what you do with one of those organs that's chock FULL of neon 
bulbs?

aa 




From Stromeko at nexgo.de  Tue Apr  8 19:34:38 2008
From: Stromeko at nexgo.de (ASSI)
Date: Tue, 8 Apr 2008 19:34:38 +0200
Subject: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
References: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
Message-ID: <200804081934.38420.Stromeko@nexgo.de>

On Dienstag 08 April 2008, Ullrich Peter wrote:
> Sorry but I have no rights to get there. No problem reaching your
> root Directory and video directory but permission is denied on the
> incoming Directory.

The normal configuration for an FTP server is that the "incoming" 
directory is only writable - you can't see or read any files there, but 
you can drop off new ones.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Wavetables for the Terratec KOMPLEXER:
http://Synth.Stromeko.net/Downloads.html#KomplexerWaves



From xyzzy at sysabend.org  Tue Apr  8 20:16:56 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Tue, 8 Apr 2008 11:16:56 -0700
Subject: [sdiy] tbDAC-2 midi-CV Convertor
In-Reply-To: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
Message-ID: <20080408181655.GH35142@moo.sysabend.org>

On Tue, Apr 08, 2008 at 09:13:52AM -0400, Nate Reeves wrote:
> anyone have one for sale, just hte PCB or even a completed one?
> i want to get MIDI on the 3031

Check out Seb's MIDI/CV for the 3031 :
http://burnit.co.uk/sdiy/index.php?page=3031

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From Peter.Ullrich at kapsch.net  Tue Apr  8 20:18:52 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Tue, 8 Apr 2008 20:18:52 +0200
Subject: AW: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <200804081934.38420.Stromeko@nexgo.de>
References: <5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>,
	<200804081934.38420.Stromeko@nexgo.de>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B704E8B11@S060VS20.kapsch.co.at>


Hi Achim!

>> Sorry but I have no rights to get there. No problem reaching your
>> root Directory and video directory but permission is denied on the
>> incoming Directory.
>
>The normal configuration for an FTP server is that the "incoming"
>directory is only writable - you can't see or read any files there, but
>you can drop off new ones.

Thanx for this information. You are right - I could copy my file to that directory.

Ciao
Peter

http://www.ullrich.at.tt



From samppa.tolvanen at gmail.com  Tue Apr  8 21:42:09 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 8 Apr 2008 22:42:09 +0300
Subject: [sdiy] 1Meg log taper pot for ADSR module..
In-Reply-To: <380-22008428123135273@oricom.ca>
References: <380-22008428123135273@oricom.ca>
Message-ID: <fa1b0bd80804081242w3893ffa0g34bb6e5d5f382936@mail.gmail.com>

Nobody seems to answer,

But - without seeing the schematics - I'd like to pose this question
to Karl Dalen.

What is Your answer - 1MOhm - Should You match those? In Which %? ;)

Samppa


From seb at burnit.co.uk  Tue Apr  8 21:51:03 2008
From: seb at burnit.co.uk (Seb Francis)
Date: Tue, 08 Apr 2008 20:51:03 +0100
Subject: [sdiy] tbDAC-2 midi-CV Convertor
In-Reply-To: <20080408181655.GH35142@moo.sysabend.org>
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
	<20080408181655.GH35142@moo.sysabend.org>
Message-ID: <47FBCCA7.8070303@burnit.co.uk>

Was just about to mention this :)
I have to check but I think I have a PCB or 2 left for this.

Seb


Tom Arnold wrote:
> On Tue, Apr 08, 2008 at 09:13:52AM -0400, Nate Reeves wrote:
>   
>> anyone have one for sale, just hte PCB or even a completed one?
>> i want to get MIDI on the 3031
>>     
>
> Check out Seb's MIDI/CV for the 3031 :
> http://burnit.co.uk/sdiy/index.php?page=3031
>
>   




From aankrom at bluemarble.net  Tue Apr  8 22:08:40 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 8 Apr 2008 16:08:40 -0400
Subject: [sdiy] TLC320AD50C: any one use one of these for a CV quantizer
	etc.?
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net><47FB9B55.6152.195439E@techman.synth.net>
	<00ca01c8999e$8b6f7880$0202a8c0@positronium>
Message-ID: <00da01c899b4$58b885b0$0202a8c0@positronium>

I got a TLC320AD50C from a modem and it looks like a pretty decent 16-bit 
siga-delta ADDAC. The first app that I thought of might be a CV quantizer, 
but might work well for an audio digital delay.

Anyone experiment with these?

cheers,
aa 




From ebrombaugh at earthlink.net  Tue Apr  8 22:53:00 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Tue, 08 Apr 2008 13:53:00 -0700
Subject: [sdiy] TLC320AD50C: any one use one of these for a CV quantizer
	etc.?
In-Reply-To: <00da01c899b4$58b885b0$0202a8c0@positronium>
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net><47FB9B55.6152.195439E@techman.synth.net>	<00ca01c8999e$8b6f7880$0202a8c0@positronium>
	<00da01c899b4$58b885b0$0202a8c0@positronium>
Message-ID: <47FBDB2C.5020407@earthlink.net>

anthony wrote:
> I got a TLC320AD50C from a modem and it looks like a pretty decent 
> 16-bit siga-delta ADDAC. The first app that I thought of might be a CV 
> quantizer, but might work well for an audio digital delay.

Looking at the data sheet it appears that this part has about 0.3dB 
(3.5%) gain error on both the ADC and DAC. That means it's accuracy at 
DC is going to be bad enough you wouldn't want to use it for pitch 
control CV applications unless you like playing off key.

If you look at the block diagram you can tell that this part is heavily 
slanted towards processing audio. Stick within that domain and it should 
perform nicely. Note however that the maximum conversion rate is 
22.05kHz, so your audio bandwidth will be somewhat limited.

Eric


From tom.corbitt at gmail.com  Tue Apr  8 23:18:00 2008
From: tom.corbitt at gmail.com (Tom Corbitt)
Date: Tue, 8 Apr 2008 17:18:00 -0400
Subject: [sdiy] how to fix a blinking/blank neon power indicator?
In-Reply-To: <00ca01c8999e$8b6f7880$0202a8c0@positronium>
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net>
	<47FB9B55.6152.195439E@techman.synth.net>
	<00ca01c8999e$8b6f7880$0202a8c0@positronium>
Message-ID: <3de47a20804081418s3ede2098va438cee22e1a7297@mail.gmail.com>

Neon lights are like diodes, it takes a certain amount of voltage to
turn them on and one they're on they're pretty much a short, which is
why you need to resistor to limit current. When the voltage gets high
enough, it generates a plasma inside the glass which gives off light.
Like all things electronic, neon bulbs have a finite lifetime, looking
at various ne-2 datasheets scattered around the web it looks like they
are commonly rated around 25k hours, which is around 3 years if left
on 24/7.

I'm sure there are a lot of factors involved in computing the wear and
tear inside the bulb, but like you I'm guessing that a big part of it
is electrode wear which probably increases the distance between the
two poles and outgasses various things into the envelope, which
increases the voltage requirements for plasma generation. As an aside,
light changes the firing characteristics as well, which is why you
sometimes see neon bulbs shielded from light in circuits.

As for your cap question, placing a cap across the leads will have the
opposite effect. The lamp will always blink, as you just have just
created an relaxation oscillator circuit (assuming you have kept the
resistor in series). If you build a line of these and set them off
running, every so often they appear to be synchronized together, in
the old days people used to call them "mystery boxes" and the like,
since it appeared to have some method to it's blinking madness (when
in fact the method is the brain's quest for patterns)

The only way to "fix" the bulb would be to apply a higher voltage to
the tube, which can be done, but it's probably not worth the effort.
If you don't mind the work and it's mechanically possible to get at,
changing the bulb is the easiest solution (you should be able to find
them just about anywhere (hamfests, surplus, digikey/mouser) for
almost nothing. Just hit google with  "ne-2"

Back in the pre-transistor days, people used neon bulbs in all kinds
of amazing ways. It was the 555/2n2222 of it's day.

Cheers,
Tom





On Tue, Apr 8, 2008 at 1:32 PM, anthony <aankrom at bluemarble.net> wrote:
> Anybody know why sometimes just out of the blue, a neon bulb will stop
> working or begin to blink intermittantly?
>
>  My guess is that there wasn't an adequate current-limiting resistor and the
> gap betwwen the electrodes widened. This would seem to explain the blinking
> ones too: the gap hasn't widened enough to keep it from firing, but it has
> to wait for enough charge to build to "jump" across.
>
>  I've also noticed that heavy inductive loads, say a variac controlling a
> 1000 watt heating element, can cause the neon bulb to go out if the setup is
> (unwisely) connected to a power strip that has a neon power indicator (the
> one I was using didn't have a surge protector so it wasn't anything to do
> with that...). But I don't know what this is about unless it somehow causes
> a voltage drop locally across the system. But it couldn't have to the
> electrical system to the whole building in a modern university.
>
>  So I had an idea to "fix" a failing bulb: connecting something like a
> polypropylene X2 rated capacitor across the neon bulb leads. I haven't tried
> this yet: I was wondering if it'd work. I have a HUGE collection of a wide
> range of MKP X2 caps taken from various power supplies.
>
>  So does anyone think this'd work?  If so what would be a good capacitance
> rating? Is there a better fix? I'd just replace the bulb, but it is a row of
> switches with the neon bulbs right inside them and these is a number of them
> that do not work. Would something like an oil-filled motor-start cap work
> better? I have a 3.5uF one rated for 450VAC and a 0.5uF one rated for
> 2500VAC (probably too small: might as well use a MPK X2...). Or a 10uF,
> 160VAC metallized paper motor-start cap maybe?
>
>  And gosh what you do with one of those organs that's chock FULL of neon
> bulbs?
>
>  aa
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From mirwin at marketbridge.ca  Wed Apr  9 00:19:10 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Tue, 8 Apr 2008 18:19:10 -0400
Subject: [sdiy] how to fix a blinking/blank neon power indicator?
References: <AB2FEE0E-A33B-438E-A728-C5DA00965CCC@comcast.net><47FB9B55.6152.195439E@techman.synth.net><00ca01c8999e$8b6f7880$0202a8c0@positronium>
	<3de47a20804081418s3ede2098va438cee22e1a7297@mail.gmail.com>
Message-ID: <001301c899c6$92600600$9adb47d1@ca>

Download the GE Neon lamp manual here (12.7 meg):

http://www.tech-systems-labs.com/books.htm




From batzman-nr at all-electric.com  Wed Apr  9 08:53:39 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Wed, 09 Apr 2008 16:23:39 +0930
Subject: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <200804081934.38420.Stromeko@nexgo.de>
References: <66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
Message-ID: <5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>

Y-ellow Achim 'n' all.

At 07:34 PM 4/8/2008 +0200, ASSI wrote:

>The normal configuration for an FTP server is that the "incoming"
>directory is only writable - you can't see or read any files there, but
>you can drop off new ones.

Yup this is indeed the case. Though we did have trouble with the FTP site a 
while back. I'd thought I'd seen to it and it was working. I haven't had 
the chance to get there and take a look at the moment. Too many balls in 
the air. And you know how painful that can be.

The reason the convention was started was that warez kiddies use to use any 
open incoming directory as a drop zone. It use to be that if you knew the 
file names that were in there, you could retrieve them. This was handy but 
the warez kiddies soon caught onto that one too so now all you can do is 
upload into an incoming. But! You should be able to poke round the rest of 
the directories. Of which you can only extract stuff from rather than put 
stuff in.

You have to let me know that something is up there and then I can shift it 
into an appropriate directory for the consumption of others. As it were.

You'll probably note that I haven't actually updated much on my actual web 
site since about 2005 or so. I was thinking I should do something about 
that but I can't find a friendly WYSIWYG HTML editor for linux. So if 
anyone has any suggestions. I mean by friendly, one that will actually 
install under slackware. But having said that, I tend to use the FTP more 
than anything these days and having the web site just allows me to have 
this wicked email system running.

Anyway, that's the story and I'm thinking of optioning it out to Hollywood.

Hope this helps.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From Peter.Ullrich at kapsch.net  Wed Apr  9 09:13:05 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Wed, 9 Apr 2008 09:13:05 +0200
Subject: AW: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
References: <66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B708881F2@S060VS20.kapsch.co.at>



Hi Batz!

>You have to let me know that something is up there and then I can
>shift it into an appropriate directory for the consumption
>of others. As it were.

OK Batz! Yesterday I put the That2159 compatible part datasheets and
The German Cybermix CM8000 into the incoming directory.

It would be nice if you could put it in an public directory and tell
Us where they are so that people can load them from there!

Thanks!

Ciao
Peter

http://www.ullrich.at.tt



From batzman-nr at all-electric.com  Wed Apr  9 11:20:49 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Wed, 09 Apr 2008 18:50:49 +0930
Subject: AW: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <66989A9506070B43A3B606F3009CB90A3B708881F2@S060VS20.kapsch
	.co.at>
References: <5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
Message-ID: <5.1.0.14.2.20080409182253.0470af60@mail.all-electric.com>

Y-ellow Peter 'n' all.

>It would be nice if you could put it in an public directory and tell
>Us where they are so that people can load them from there!

Yup. Not a problem. Well, in theory. Give me a couple of days. I'm tied up 
tomorrow and I just realized that I didn't copy my FTP client over when I 
rebuilt this system. Doh! So now I have to figure out how to get in there 
myself. Don't worry, I'm sure I have the password somewhere. :)

At least that's a better situation than I was in 2 weeks ago. I was down to 
one working linux box and no email at all. All because of upgrades and 
maintenance followed by power failures and power backup that didn't. I'm 
still far from out of the woods as it were but I'm getting there.

Anyway, Bear with me and I'll make it so.

Thanks once again.
Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From batzman-nr at all-electric.com  Wed Apr  9 16:18:54 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Wed, 09 Apr 2008 23:48:54 +0930
Subject: AW: AW: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080409182253.0470af60@mail.all-electric.com>
References: <66989A9506070B43A3B606F3009CB90A3B708881F2@S060VS20.kapsch .co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
Message-ID: <5.1.0.14.2.20080409234421.046827a8@mail.all-electric.com>

Y-ellow all.
         Well that was easier than I thought it was going to be. The 
Behringer data is now here and publicly accessible.

ftp://all-electric.com/behringer-cybermix-cm8000-data

Thanks again, and hope this helps.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From tsheets at saturn5.com  Wed Apr  9 17:15:55 2008
From: tsheets at saturn5.com (tsheets at saturn5.com)
Date: Wed, 9 Apr 2008 08:15:55 -0700
Subject: [thomas@thomaslaskowski.com: [sdiy] FS: possible ASM-1 for sale]
In-Reply-To: <20080403233644.GA6129@atari.saturn5.com>
References: <20080403233644.GA6129@atari.saturn5.com>
Message-ID: <20080409151554.GA7939@atari.saturn5.com>



This deal has been worked out.  My money has been refunded.

-troy

On Thu, Apr 03, 2008 at 04:36:44PM -0700, tsheets at saturn5.com wrote:
> 
> 
> Hi, I paypal-ed Thomas $350 for this ASM-1 exactly 4 weeks ago today,
> and I still don't have a tracking number, and the last email I got from him
> was about 2 weeks ago.  I would warn anyone against future purchases from him.
> 
> If the situation changes, I will happily notify this list.
> 
> -troy
> 
> 
> ----- Forwarded message from Thomas Laskowski <thomas at thomaslaskowski.com> -----
> 
> 
> Hi guys,
> 
> I used to be a member while I was at university.  That was several years 
> ago.  I have a pretty much fully assembled ASM-1 with front panel, patch 
> cables (stackable banana plugs), and all.  You can look at the pictures 
> here (some of those are outdated) 
> http://www.thomaslaskowski.com/asm1/ASM-1.html
> I can take more pictures.
> I believe that all the wiring to the panel is complete and I have done 
> some testing.  I also have a power supply that I can throw in.  But no 
> MIDI-CV converter sorry.
> 
> If anyone is interested please make me an offer.  It's been sitting in 
> the basement for a few years now without any use.  I believe that 
> someone could find a use for it.
> 
> I can retest it again because it hasn't been used in a long time.  But 
> it's guaranteed to work.
> 
> Sorry to barge in like this, but I need to do some clean up.
> 
> Cheers,
> 
> -Tom
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> ----- End forwarded message -----
> 
> -- 
> ------------------------------------------------------------------------------
> tsheets at saturn5.com                                  <- You have found me   
> http://www.ferrapsylix.com                           <- sub atomic breakbeat
> "I just don't have the discipline to be a hippie"    <- Homer J. Simpson
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
------------------------------------------------------------------------------
tsheets at saturn5.com                                  <- You have found me   
http://www.ferrapsylix.com                           <- sub atomic breakbeat
"I just don't have the discipline to be a hippie"    <- Homer J. Simpson


From djservs at comcast.net  Wed Apr  9 17:43:15 2008
From: djservs at comcast.net (Nate Reeves)
Date: Wed, 9 Apr 2008 11:43:15 -0400
Subject: [sdiy] PCM53JP-1 IC locate hunt
Message-ID: <13CC2936-CA0E-43BF-9226-F602E9D73A76@comcast.net>

anyone know if these are available?
anyone want to sell me one?
cheers
nate



From Peter.Ullrich at kapsch.net  Thu Apr 10 08:19:39 2008
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Thu, 10 Apr 2008 08:19:39 +0200
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <5.1.0.14.2.20080409234421.046827a8@mail.all-electric.com>
References: <66989A9506070B43A3B606F3009CB90A3B708881F2@S060VS20.kapsch
	.co.at>	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<5.1.0.14.2.20080409234421.046827a8@mail.all-electric.com>
Message-ID: <66989A9506070B43A3B606F3009CB90A3B7088872C@S060VS20.kapsch.co.at>


Hello Batz!

Thank you very much for offering your webspace!

Ciao
Peter

http://www.ullrich.at.tt


-----Urspr?ngliche Nachricht-----
Von: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-bounces at dropmix.xs4all.nl] Im Auftrag von Batz Goodfortune
Gesendet: Mittwoch, 09. April 2008 16:19
An: synth-diy at dropmix.xs4all.nl
Betreff: Re: AW: AW: [sdiy] Behringer Cybermix CM8000


Y-ellow all.
         Well that was easier than I thought it was going to be. The Behringer data is now here and publicly accessible.

ftp://all-electric.com/behringer-cybermix-cm8000-data

Thanks again, and hope this helps.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass
| world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From richard.e.johnson at gmail.com  Thu Apr 10 15:30:29 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Thu, 10 Apr 2008 09:30:29 -0400
Subject: [sdiy] Greetings
Message-ID: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>

Hello All!

Let me introduce myself:

My name is Ric Johnson and I've recently become interested in building
very small and simple synth circuits (Oscillators, Filters, LFOs). My
goal is for them to be an "output stage" for larger art and technology
projects--as opposed to standalone synths .

I'll camp for a while and check the archives before I start in with
the newbie stuff. :)

Are there any tricks to finding information in the archives (other
than the obvious)?

Thanks!
Ric


From aankrom at bluemarble.net  Thu Apr 10 21:14:25 2008
From: aankrom at bluemarble.net (anthony)
Date: Thu, 10 Apr 2008 15:14:25 -0400
Subject: [sdiy] water noises?
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com><20080407192312.GA8093@cs.wisc.edu>
	<001701c8997e$72b8c5a0$2d8bfe04@tim3>
Message-ID: <003701c89b3f$192550e0$0202a8c0@positronium>

What is the best way with synth DIY techniques to make sounds that resemble 
the noises that water makes in various situations: like falling over a 
waterfall (and hitting at the bottom, splashing in the tub, water dripping 
into water, many bubbles coming to the surface of water? I'm guessing that a 
number of techniques would be needed; some sort of variation of a pink noise 
generator would probably be the starting point of many of them.

Running a random S/H, triggered by a moderately fast LFO,  sending control 
voltages to a very resonant phaser makes decent popping noises like water. 
But the thing I do this with is actually a digital phaser: the Boss PH-3 set 
to step with the resonance set high. But the step setting really isn't 
random. (But that phaser is awesome anyway...)

And I'm talking strictly analog methods here. I'll bet Risset tones could 
approximate water. But I've only seen them done in the digital domain, 
although it seems possible to do it with analog (maybe much like it seems 
possible to do a Fourier Transform in analog?).

I remember Ken Stone saying his Modulo Magic unit could simulate rising 
bubbles and such.

Thoughts?

cheers,
aa 




From richard.e.johnson at gmail.com  Thu Apr 10 21:34:19 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Thu, 10 Apr 2008 15:34:19 -0400
Subject: [sdiy] Greetings
In-Reply-To: <6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>
	<6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
Message-ID: <be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>

I've seen the "Lunettas" forum there. That's right up my alley! The
simpler the better.

I'll have to poke around there some more.

I had a flash one night of a modular synth with each module
constructed on the Radio Shack 276-159 circuit board.

See pic:
  http://www.geocities.com/teleman28056/pictures/rs_276-159b_pcb.jpg
  http://rsk.imageg.net/graphics/product_images/pRS1C-2266446w345.jpg

The Radio Shack page (
http://www.radioshack.com/sm-dual-general-purpose-ic-pc-board--pi-2103799.html
) says "Accepts two 6 to 20-pin ICs and DIPs" But I know for a FACT
you can squeeze 2 4-pin DIPs on there! Op Amp and NAND gate anyone? Am
I nuts? :)

Ric

On Thu, Apr 10, 2008 at 9:53 AM, Dave Kendall <davekendall at ntlworld.com> wrote:
> Hi Ric.
>
>  You might also want to check out the electro-music synth diy forum at
>  http://electro-music.com/forum/forum-112.html
>
>  There are some heavyweight synth designers and builders there too, and
> newbies are genuinely welcomed :-)
>
>  Dave
>  (still a newbie after 4 years ;-)
>
>
>
>  On Apr 10, 2008, at 14:30, Richard Johnson wrote:
>
>
> >
> >
> >
> > Hello All!
> >
> > Let me introduce myself:
> >
> > My name is Ric Johnson and I've recently become interested in building
> > very small and simple synth circuits (Oscillators, Filters, LFOs). My
> > goal is for them to be an "output stage" for larger art and technology
> > projects--as opposed to standalone synths .
> >
> > I'll camp for a while and check the archives before I start in with
> > the newbie stuff. :)
> >
> > Are there any tricks to finding information in the archives (other
> > than the obvious)?
> >
> > Thanks!
> > Ric
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >
> >
>
>


From rtellason at verizon.net  Thu Apr 10 23:33:41 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Thu, 10 Apr 2008 17:33:41 -0400
Subject: [sdiy] Greetings
In-Reply-To: <be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>
	<6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
	<be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
Message-ID: <200804101733.42187.rtellason@verizon.net>

On Thursday 10 April 2008 15:34, Richard Johnson wrote:
> I've seen the "Lunettas" forum there. That's right up my alley! The
> simpler the better.
>
> I'll have to poke around there some more.
>
> I had a flash one night of a modular synth with each module
> constructed on the Radio Shack 276-159 circuit board.
>
> See pic:
>   http://www.geocities.com/teleman28056/pictures/rs_276-159b_pcb.jpg
>   http://rsk.imageg.net/graphics/product_images/pRS1C-2266446w345.jpg
>
> The Radio Shack page (
> http://www.radioshack.com/sm-dual-general-purpose-ic-pc-board--pi-2103799.h
>tml ) says "Accepts two 6 to 20-pin ICs and DIPs" But I know for a FACT you
> can squeeze 2 4-pin DIPs on there! Op Amp and NAND gate anyone? Am I nuts?
> :)
>
> Ric

Yup!  Yeah you could squeeze a couple of 8-pin DIPs on that board,  but then 
there's surely not enough room for much else...

I like to spread out a little more,  myself.  :-)


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From somnium7 at gmail.com  Fri Apr 11 00:18:31 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Thu, 10 Apr 2008 18:18:31 -0400
Subject: [sdiy] non-gain distortions
Message-ID: <916920440804101518g7c1eba35sd3af5e7f7498ec3d@mail.gmail.com>

besides the usual ring/amplitude modulation, bit reduction and
waveshaping circuits, what are some other neat tricks for creating
distortion that don't involve high gain?

Mike


From profpep at hotmail.com  Fri Apr 11 01:23:00 2008
From: profpep at hotmail.com (Mike)
Date: Fri, 11 Apr 2008 00:23:00 +0100
Subject: [sdiy] non-gain distortions
References: <916920440804101518g7c1eba35sd3af5e7f7498ec3d@mail.gmail.com>
Message-ID: <BAY111-DAV53F71644DCE4DFFAD9381A1EC0@phx.gbl>

From: "mike ruberto"

> besides the usual ring/amplitude modulation, bit reduction and
> waveshaping circuits, what are some other neat tricks for creating
> distortion that don't involve high gain?
>
Non - linear circuits in general like:
diode shapers/function generators - think lateral, her are some wierd and
wonderful diodes out here. I once got a good result with an old automotive
copper-oxide or selenium rectifier
deliberately mis-biased transistors/FET's
op amps with non linear feedback.

You can do some neat tricks with a poor mans take on a saturable reactor -
putting the signal through one winding of an audio transformer, and putting
a variable DC bias through the other.

A bulb 'baretter' analogue - like a small power amp feeding the signal
trough a 'loaded' small low current filament lamp. Pick the signal up across
the load, or use a small stranformer as the load and get jthe signal from
the secondary.

Signal through a not very linear optocoupler.

Digital dstort, using and A->D feeding the address lines of a RAM or ROM,
output data feeding a D->A, The RAM/ROM content determine the output, if
address contains it's own value, output is linear, if you divide the data
into bands, some variants are called Bitcrushing.

Hope this helps, for a start - do you want exotic, or cheap and simple?

Mike





From aurastar at cox.net  Fri Apr 11 01:28:32 2008
From: aurastar at cox.net (DTK)
Date: Thu, 10 Apr 2008 19:28:32 -0400
Subject: [sdiy] Assistance from list members in Germany?
Message-ID: <00be01c89b62$972ce020$6500a8c0@athlonxp>

I need some assistance contacting a company located in Germany, and could 
use a hand from someone local.  Please contact me off list if you're willing 
to make a quick phone call on my behalf, it would be much appreciated.

Thanks!

DTK 



From pfperry at melbpc.org.au  Fri Apr 11 02:08:32 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 11 Apr 2008 10:08:32 +1000
Subject: [sdiy] water noises?
In-Reply-To: <003701c89b3f$192550e0$0202a8c0@positronium>
Message-ID: <000401c89b68$2e18cb20$8501a8c0@ice9>

Maybe a starting point would be to look at actual samples, and try to
deconstruct them with sonogram producing software.

I suspect that using low frequency 1/F noise to sweep a filter would be part
of it.

Paul perry Melbourne Australia




From davekendall at ntlworld.com  Fri Apr 11 03:03:12 2008
From: davekendall at ntlworld.com (Dave Kendall)
Date: Fri, 11 Apr 2008 02:03:12 +0100
Subject: [sdiy] water noises?
In-Reply-To: <003701c89b3f$192550e0$0202a8c0@positronium>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com><20080407192312.GA8093@cs.wisc.edu>
	<001701c8997e$72b8c5a0$2d8bfe04@tim3>
	<003701c89b3f$192550e0$0202a8c0@positronium>
Message-ID: <0EE4AED8-0763-11DD-92CE-000393A85F9E@ntlworld.com>

One of the things that was interesting I found in the years when I did 
a lot of hobby portable DAT recording, and when I dubbed a lot of 
corporate stuff, TV and a few films, was that actual real recordings of 
weather are often  peculiarly monotonous and almost unidentifiable in 
many cases.
As an example, the sound of rain hitting a roof and steady wind are 
pretty much white or coloured noise. A waterfall is pretty much pure 
pink noise, the frequency spectrum changing, depending on how far away 
you are. In order to make these sounds work with video, or in isolation 
as pure audio to tell  a story or give an impression, some non rhythmic 
audio clues are needed. With rain, added individual "plinks" of 
raindrops made the overall effect so much more convincing, even if the 
surface they fell on wouldn't have sounded like that. OTOH, a recording 
of a small stream with stones in is pretty much a modulated sound, so 
has enough detail in it to be easy to recognise. The classic howling 
wind made with a synth white/pink noise source  through a bandpass or 
low pass filter is used so often in preference to a real recording, 
because the real sound is so much more boring. A recording of wind in 
pine trees I once made only works, because the wind changes speed 
constantly with the gusts, and the trees respond by creaking and 
moaning. The odd owl hoot helps too.

IMO the devil (and the successful illusion) is in the detail. :-)

Cheers,
Dave



On Apr 10, 2008, at 20:14, anthony wrote:

> What is the best way with synth DIY techniques to make sounds that 
> resemble the noises that water makes in various situations: like 
> falling over a waterfall (and hitting at the bottom, splashing in the 
> tub, water dripping into water, many bubbles coming to the surface of 
> water? I'm guessing that a number of techniques would be needed; some 
> sort of variation of a pink noise generator would probably be the 
> starting point of many of them.
>
> Running a random S/H, triggered by a moderately fast LFO,  sending 
> control voltages to a very resonant phaser makes decent popping noises 
> like water. But the thing I do this with is actually a digital phaser: 
> the Boss PH-3 set to step with the resonance set high. But the step 
> setting really isn't random. (But that phaser is awesome anyway...)
>
> And I'm talking strictly analog methods here. I'll bet Risset tones 
> could approximate water. But I've only seen them done in the digital 
> domain, although it seems possible to do it with analog (maybe much 
> like it seems possible to do a Fourier Transform in analog?).
>
> I remember Ken Stone saying his Modulo Magic unit could simulate 
> rising bubbles and such.
>
> Thoughts?
>
> cheers,
> aa
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>



From ka4hjh at gte.net  Fri Apr 11 03:22:21 2008
From: ka4hjh at gte.net (KA4HJH)
Date: Thu, 10 Apr 2008 21:22:21 -0400
Subject: [sdiy] water noises?
In-Reply-To: <000401c89b68$2e18cb20$8501a8c0@ice9>
References: <000401c89b68$2e18cb20$8501a8c0@ice9>
Message-ID: <p06240800c4246d5e9b96@[192.168.1.101]>

>Maybe a starting point would be to look at actual samples, and try to
>deconstruct them with sonogram producing software.
>
>I suspect that using low frequency 1/F noise to sweep a filter would be part
>of it.

Modulating a VCO with noise is another trick. IIRC that's how Suzanne Ciani
did the famous 7up fizz.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"


From pfperry at melbpc.org.au  Fri Apr 11 03:22:32 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 11 Apr 2008 11:22:32 +1000
Subject: [sdiy] water noises?
In-Reply-To: <0EE4AED8-0763-11DD-92CE-000393A85F9E@ntlworld.com>
Message-ID: <000c01c89b72$844aa2c0$8501a8c0@ice9>

Dave is entirely right about some actual recordings not sounding as much
like the real thing, compared to a synthesized version.
There was a Suzanne Ciani interview where she talked about making a "bacon
frying" sound. The sound that worked, was very different from what actually
happens when bacon fries.

Why this should be true for some sounds, and not others, I do not know.

Paul Perry Melbourne Australia




From ka4hjh at gte.net  Fri Apr 11 04:59:59 2008
From: ka4hjh at gte.net (KA4HJH)
Date: Thu, 10 Apr 2008 22:59:59 -0400
Subject: [sdiy] water noises?
In-Reply-To: <000c01c89b72$844aa2c0$8501a8c0@ice9>
References: <000c01c89b72$844aa2c0$8501a8c0@ice9>
Message-ID: <p06240801c42483ccdd6a@[192.168.1.101]>

>Dave is entirely right about some actual recordings not sounding as much
>like the real thing, compared to a synthesized version.
>There was a Suzanne Ciani interview where she talked about making a "bacon
>frying" sound. The sound that worked, was very different from what actually
>happens when bacon fries.

Great minds. IIRC it was in Keyboard and it was reprinted in an interview
collection.

Mind you all my train recordings sound great.

>Why this should be true for some sounds, and not others, I do not know.

I've wondered about this for years. I suspect there's some psychoacoustics
involved. Sound is subjective.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"


From somnium7 at gmail.com  Fri Apr 11 12:17:15 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Fri, 11 Apr 2008 06:17:15 -0400
Subject: [sdiy] non-gain distortions
In-Reply-To: <BAY111-DAV53F71644DCE4DFFAD9381A1EC0@phx.gbl>
References: <916920440804101518g7c1eba35sd3af5e7f7498ec3d@mail.gmail.com>
	<BAY111-DAV53F71644DCE4DFFAD9381A1EC0@phx.gbl>
Message-ID: <916920440804110317v7cb29a33h4382b81aabc2b8f8@mail.gmail.com>

I remember doing some experiments when I was younger. I was taking
apart old transistor stereos and running signals into the different
circuit boards while varying the supply voltage to them. I remember
getting some interesting results.

I had this old rhythm box which had a torn speaker. Made great
distorted bass noises.

The reactor idea sound kinda neat. That might be a fun little project...

Mike

On Thu, Apr 10, 2008 at 7:23 PM, Mike <profpep at hotmail.com> wrote:
> From: "mike ruberto"
>
>
>  > besides the usual ring/amplitude modulation, bit reduction and
>  > waveshaping circuits, what are some other neat tricks for creating
>  > distortion that don't involve high gain?
>  >
>  Non - linear circuits in general like:
>  diode shapers/function generators - think lateral, her are some wierd and
>  wonderful diodes out here. I once got a good result with an old automotive
>  copper-oxide or selenium rectifier
>  deliberately mis-biased transistors/FET's
>  op amps with non linear feedback.
>
>  You can do some neat tricks with a poor mans take on a saturable reactor -
>  putting the signal through one winding of an audio transformer, and putting
>  a variable DC bias through the other.
>
>  A bulb 'baretter' analogue - like a small power amp feeding the signal
>  trough a 'loaded' small low current filament lamp. Pick the signal up across
>  the load, or use a small stranformer as the load and get jthe signal from
>  the secondary.
>
>  Signal through a not very linear optocoupler.
>
>  Digital dstort, using and A->D feeding the address lines of a RAM or ROM,
>  output data feeding a D->A, The RAM/ROM content determine the output, if
>  address contains it's own value, output is linear, if you divide the data
>  into bands, some variants are called Bitcrushing.
>
>  Hope this helps, for a start - do you want exotic, or cheap and simple?
>
>  Mike
>
>
>
>


From batzman-nr at all-electric.com  Fri Apr 11 12:40:58 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Fri, 11 Apr 2008 20:10:58 +0930
Subject: [sdiy] Behringer Cybermix CM8000
In-Reply-To: <66989A9506070B43A3B606F3009CB90A3B7088872C@S060VS20.kapsch
	.co.at>
References: <5.1.0.14.2.20080409234421.046827a8@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B708881F2@S060VS20.kapsch .co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080408000429.01e37c48@mail.all-electric.com>
	<5.1.0.14.2.20080408174249.046e4b80@mail.all-electric.com>
	<66989A9506070B43A3B606F3009CB90A3B70887ECD@S060VS20.kapsch.co.at>
	<5.1.0.14.2.20080409161332.04692eb0@mail.all-electric.com>
	<5.1.0.14.2.20080409234421.046827a8@mail.all-electric.com>
Message-ID: <5.1.0.14.2.20080411200058.04751468@mail.all-electric.com>

Y-ellow Peter 'n' all.

At 08:19 AM 4/10/2008 +0200, Ullrich Peter wrote:

>Hello Batz!
>
>Thank you very much for offering your webspace!

Pleasure. If there's anything else related that needs to go up there just 
let me know.

BTW. In theory, I now own one. I have to wait for the thing to arrive. Any 
suggestions as to a quick way to analyze the RS232 data? I guess a protocol 
analyzer would be the shot. Don't have one of them. All my logic analyzer 
gear is oriented more toward system logic rather than bit streams. I'm 
wondering if there was some kind of RS232 spy program that could eaves drop 
on the bit stream? I'm guessing you'd need 2 spare ports for that. Assuming 
the box sends back an Ack when it gets a message.

Anyway, Thanks again for the input.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From daugard at sprintmail.com  Fri Apr 11 15:48:24 2008
From: daugard at sprintmail.com (Tim Daugard)
Date: Fri, 11 Apr 2008 08:48:24 -0500
Subject: [sdiy] Greetings
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com><6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
	<be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
Message-ID: <003601c89bda$b7c3d6e0$0d8bfe04@tim3>

From: "Richard Johnson" <richard.e.johnson at gmail.com>

> I had a flash one night of a modular synth with each module
> constructed on the Radio Shack 276-159 circuit board.
>
> http://www.radioshack.com/sm-dual-general-purpose-ic-pc-board--pi-2103799.html
> ) says "Accepts two 6 to 20-pin ICs and DIPs" But I know for a FACT
> you can squeeze 2 4-pin DIPs on there! Op Amp and NAND gate anyone? Am
> I nuts? :)


http://home.earthlink.net/~synthfred/chp05c0.htm

This link is my method. I started with the radio shack board, but the holes are too big to
get reliable connections with ICs (and sockets.) I also had problems with solder bridges
with those boards. Radio Shack has a cheaper board that is just as easy to use.

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
http://home.sprintmail.com/~daugard/synth.htm
http://home.earthlink.net/~synthfred/h_toctop.htm (Fred's online edition)



From richard.e.johnson at gmail.com  Fri Apr 11 19:29:24 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Fri, 11 Apr 2008 13:29:24 -0400
Subject: [sdiy] Greetings
In-Reply-To: <003601c89bda$b7c3d6e0$0d8bfe04@tim3>
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>
	<6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
	<be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
	<003601c89bda$b7c3d6e0$0d8bfe04@tim3>
Message-ID: <be8b34180804111029j56d5b67cr847b13c1122ae447@mail.gmail.com>

Wow, Tim! Can I just say WOW!

First, the idea of using Junction boxen is BRILLIANTLY evil!
I'll also heed your advise on the issues with that board.

But mostly a big THANK YOU for writing a book with EXACTLY the kind of
"very small circuits" I've been looking for! VERY VERY cool!

And I *never* use caps!

Do you have and print copy mockups of the book? Or can you make it
avalible therogh Cafe Press?
It'd be free to you and I'd buy it to have the hard copy.

Thanks!
Ric

On Fri, Apr 11, 2008 at 9:48 AM, Tim Daugard <daugard at sprintmail.com> wrote:
>  http://home.earthlink.net/~synthfred/chp05c0.htm
>
>  This link is my method. I started with the radio shack board, but the holes are too big to
>  get reliable connections with ICs (and sockets.) I also had problems with solder bridges
>  with those boards. Radio Shack has a cheaper board that is just as easy to use.
>
>  Tim Daugard
>  AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
>  http://home.sprintmail.com/~daugard/synth.htm
>  http://home.earthlink.net/~synthfred/h_toctop.htm (Fred's online edition)


From jmahoney at gate.net  Sat Apr 12 01:34:03 2008
From: jmahoney at gate.net (John Mahoney)
Date: Fri, 11 Apr 2008 19:34:03 -0400
Subject: [sdiy] Greetings
In-Reply-To: <be8b34180804111029j56d5b67cr847b13c1122ae447@mail.gmail.co
 m>
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>
	<6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
	<be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
	<003601c89bda$b7c3d6e0$0d8bfe04@tim3>
	<be8b34180804111029j56d5b67cr847b13c1122ae447@mail.gmail.com>
Message-ID: <200804112333.m3BNXBZg031398@dropmix.xs4all.nl>

At 01:29 PM 4/11/2008, Richard Johnson wrote:

>... Junction boxen ...

"Boxen?" Let me guess, you're a Linux user!

I guess it all started with "Vaxen."

John the curmudgeon ;-)


-- 
No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.12/1374 - Release Date: 4/11/2008 4:59 PM




From rkmoore at memphis.edu  Sat Apr 12 10:31:33 2008
From: rkmoore at memphis.edu (Richard Kirk Moore (rkmoore))
Date: Sat, 12 Apr 2008 03:31:33 -0500
Subject: [sdiy] stuff for sale for any list member close to Memphis, TN, USA
Message-ID: <5D5C650D7DFB36499E147E4243E233230875E91B82@itexbe5.uom.memphis.edu>


I'm moving out of state and need to lighten the load. I am offering the following for sale at a garage sale this Saturday 8-12 at 1117 Wilmore Rd, Memphis, 38117.

PAiA 2700 modular synthesizer cabinet with hacked joystick controller(PS, VCO, BPF, LPF, LFO (not working), VCA (noisy)): $130
Peavey linemix 8 hi-z 8 channel mixer with 2 aux busses: $50
Peavey DEP-1300 digital delay: $40
Huge metal RCA 19" rack (more than 7 feet high): $100
Altec bass cabinet with EVM-15B, sounds great!:$100
a nice White Instruments passive LC 32 band equalizer: $50
Altec horn driver and baffle, no cabinet, needs a diaphram:$30
Conn Prelude organ, three broken keys, but mostly works:$30
Casio CTK-411, with MIDI:$15
Davis upright piano, quite old but plays ok, missing one caster:$100
Magnus chord organ, works fine, sounds neat:$20

http://memphis.craigslist.org/msg/638142610.html

http://maps.google.com/maps?f=q&hl=en&geocode=&q=1117+wilmore+38117&sll=37.0625,-95.677068&sspn=86.135299,114.257813&ie=UTF8&z=16&iwloc=addr


Sorry that i don't have pictures up for most of the stuff.

Richard



From prowlerraven32 at hotmail.com  Sat Apr 12 17:25:51 2008
From: prowlerraven32 at hotmail.com (Logan Mitchell Sr)
Date: Sat, 12 Apr 2008 11:25:51 -0400
Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
 changes from Logan for 04/12/2008
Message-ID: <BAY110-W16E31BCB7E0C919F811979C1EE0@phx.gbl>


04/12/2008

Hi Frank. There's been a location & time change. We'll now meet at the Golden Corral Restaurant on Chesapeake Drive at 2:00 pm today (Golden Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 (410) 590-0270, (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02).  ).

The manager was nice enough to provide us with a room that has electrical outlets for us to plug our stuff up. See the msg below that I sent to Dave VOSHyesterday. I may leave at little early to make some stops along the way. My cellphone number is 410-258-1875 & my pager number w/voice-mail is 1-800-815-5929. I'll notify the rest of the group. Hope to see you there. Ask for Tony the manager & I'll ask him to direct you to the room which we'll have the use of from 2:00 to 4:00 pm today. Thanks.


Logan


RE: Baltimore SDIY Meet & Greet Proposal from Logan?


From:
Logan Mitchell Sr (prowlerraven32 at hotmail.com)


Sent:
Fri 4/11/08 5:57 PM


To:
davevosh at aol.com


Dave

The capability to dial my pager number from a payphone was taken away years ago. I asked them about us setting up in the booths but they have no electrical outlets in the booths. We may have to look for another location such as a library unless you still want to meet there and hope for the magic electric outlet to show up in another part of the diner. GOOD NEWS - Here's a better location that I go to with the family, Golden Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 (410) 590-0270, (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02). I just talked to Tony who is the manager at

this location. I explained to him what we will be doing & that we need an outlet. He has a room that we can use from 2:00 pm to 4:00 pm as long as we are there by 2:00 pm tomorrow. I told him that we'll see him there tomorrow if you're for it, so bring your electronics. I also told him that we will be using headphones. Let me know what you think. This location is 2 blocks from Ritchie Highway.

Logan


> From: fvanaman at gadgetland.net
> To: prowlerraven32 at hotmail.com
> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
> Date: Sat, 12 Apr 2008 10:28:35 -0400
>
> 'morning--
>
> Looks like today's other festivities should be done in time for me to make
> it down. I'm just about to go out a few hours - but was just wondering
> whether you settled on a more definite time this afternoon (and whether or
> not it was still at the Mountain Road Double-T).
>
> I'm forwarding a copy to Jeff to see if he might be able to make it...
>
> Frank
>
> -----Original Message-----
> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
> Sent: Thursday, April 10, 2008 10:27 AM
> To: fvanaman at gadgetland.net
> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>
>
> Hi Frank. If you can make it let me know around 5:00 pm on Saturday. You can
> call me on my pager with voice-mail at 1-800-815-5929. This system is
> limited to a 30 second recording time per voice-mail so if it cuts off just
> call right back to leave another message. Leave me a callback number too.
> Thanks & I'll keep you posted if you can't make it. Bring Jeff with you if
> you can.
>
> Logan
> ________________________________
>
> From: fvanaman at gadgetland.net
> To: prowlerraven32 at hotmail.com
> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
> Date: Thu, 10 Apr 2008 09:47:03 -0400
>
>
>
>
>
> 'morning--
>
>
>
> Meeting (and eating) at a diner seems entirely appropriate for Synth
> D-I-Y'ers! :-) The Mountain Road Double-T would be cool. I'm particularly
> fond of the Double-T north of Whitemarsh on Route 1, and sometimes meet up
> with JeffK ('analoguejeff' on AH) over there.
>
>
>
> My Saturday is very full in the afternoon, and involves trundling my mom to
> a couple things (which expands the time needed considerably), and also a
> couple of already-arranged house viewings, so I'm not sure I'll be done in
> time for this one.
>
>
>
> Keep me posted, though, and I'll try my best,
>
>
>
> Frank
>
>
>
> ________________________________
>
> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
> Sent: Wednesday, April 09, 2008 10:37 AM
> To: fvanaman at gadgetland.net; davevosh at aol.com; gregae at comcast.net;
> alfred.pear at gmail.com; dgrickert at hotmail.com; prowlerraven32 at hotmail.com;
> ronwest at gmail.com
> Subject: Baltimore SDIY Meet & Greet Proposal from Logan
>
>
> 04/08/2008
>
> Hello to all & welcome to the first informal meeting of the newly formed
> Baltimore SDIY (Synthesizer Do It Yourself) Group. My name is Logan Mitchell
> Sr and in November of 2007 I decided that it was time to try & form an SDIY
> group here in Baltimore since all of the other groups seem to be located in
> the upper Northeast or Northwest part of the country. Due to the distances &
> today's increasing gas prices I find it difficult to attend any of these
> meetings. I really didn't know if anyone else would be interested in doing
> something like this so I was afraid that it might not work but that has now
> changed because you have decided to particpate in this endeavor of mine for
> which I am very grateful.
>
> I am hoping that more s-d-i-yers join the group. For our first face-to-face
> meeting I would like to propose that we meet at a restaurant which has a
> separate room similar to what the Double T Diner has. Here's a location that
> closes off its Dining Room from 2:00 to 4:30pm but only on Mon thru Fri -
> Double T Diner Co 1 Mountain Rd, Pasadena, MD 21122 (410) 766-9669
> (http://localsearch.live.com/localsearch/Details.aspx?what=diners&where=Glen
> +Burnie%2c+MD&tab=businessinfo&lid=YN404x7302805&qt=yp&s_cid=ansPhBkYp02&FOR
> M=LLDP).
>
> If you know of a better centralized location that's easy to get to then
> please let me know because I want everyone to be able to get there easily &
> economically as well.
>
> Since I live in Northwest Baltimore 2 blocks from Pimlico Racetrack &
> everyone else lives in White Marsh and Upper Marlboro, it seems like this
> may be a good central location for us to meet on a temporary or permanent
> basis. Let me know what you think and maybe we can do a Meet & Greet this
> Saturday (04/12/2008) say around 5:00 or 6:00 pm. Thanks.
>
> Logan
>
> Current members:
> Logan Mitchell Sr ProwlerRaven32 at hotmail.com (Baltimore MD) Alfred PEAR
> Alfred.Pear at gmail.com (Baltimore MD) Frank VANAMAN FVanaman at gadgetland.net
> Dave VOSH DaveVosh at aol.com (Upper Marlboro MD) Ron WEST Ron.West at gmail.com
> (White Marsh MD) Greg KIST GregAE at comcast.net (Columbia MD) David RICKERT
> DGRickert at hotmail.com (Washington DC)
>
>
> ________________________________
>
> Get in touch in an instant. Get Windows Live Messenger now.
>
>
> No virus found in this incoming message.
> Checked by AVG.
> Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 4/9/2008
> 7:10 AM
>
>
>
> No virus found in this outgoing message.
> Checked by AVG.
> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 4/9/2008
> 4:20 PM
>
> _________________________________________________________________
> Use video conversation to talk face-to-face with Windows Live Messenger.
> http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGLM_WL
> _Refresh_messenger_video_042008
>
> No virus found in this incoming message.
> Checked by AVG.
> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 4/9/2008
> 4:20 PM
>
>
> No virus found in this outgoing message.
> Checked by AVG.
> Version: 7.5.519 / Virus Database: 269.22.12/1374 - Release Date: 4/11/2008
> 4:59 PM
>
>

_________________________________________________________________
Going green? See the top 12 foods to eat organic.
http://green.msn.com/galleries/photos/photos.aspx?gid=164&ocid=T003MSN51N1653A


From rtellason at verizon.net  Sat Apr 12 17:57:34 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sat, 12 Apr 2008 11:57:34 -0400
Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
	changes from Logan for 04/12/2008
In-Reply-To: <BAY110-W16E31BCB7E0C919F811979C1EE0@phx.gbl>
References: <BAY110-W16E31BCB7E0C919F811979C1EE0@phx.gbl>
Message-ID: <200804121157.34929.rtellason@verizon.net>

On Saturday 12 April 2008 11:25, Logan Mitchell Sr wrote:
> 04/12/2008
>
> Hi Frank. There's been a location & time change. We'll now meet at the
> Golden Corral Restaurant on Chesapeake Drive at 2:00 pm today (Golden
> Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060
> (410) 590-0270,
> (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=
>yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02).  ).
>
> The manager was nice enough to provide us with a room that has electrical
> outlets for us to plug our stuff up. See the msg below that I sent to Dave
> VOSHyesterday. I may leave at little early to make some stops along the
> way. My cellphone number is 410-258-1875 & my pager number w/voice-mail is
> 1-800-815-5929. I'll notify the rest of the group. Hope to see you there.
> Ask for Tony the manager & I'll ask him to direct you to the room which
> we'll have the use of from 2:00 to 4:00 pm today. Thanks.
>
> Logan

(Big snip...)

Oh my.  Too bad this has to happen just now,  as this one I could actually 
(maybe) get to.   I guess I'll just have to hope that next time works 
better...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From rtellason at verizon.net  Sat Apr 12 19:18:37 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sat, 12 Apr 2008 13:18:37 -0400
Subject: [sdiy] Simple VCA?
Message-ID: <200804121318.37275.rtellason@verizon.net>

I've got this "Modern Electronic Circuits Reference Manual" I acquired 
recently,  not all that modern since it was published in 1980,  but I started 
browsing it anyhow...

There's one circuit I ran across that I'm wondering about,  never saw it 
actually used anywhere and I don't know how well this would work,  so I 
figured I'd toss it out for you guys to pick apart.

It's a very simple circuit,  really.  An op amp inverting amplifier,  one 
resistor going from the non-inverting input to ground,  one input resistor, 
and one feedback resistor.  And,  a JFET connected between the two input 
terminals with the gate lead labeled as being the gain input.

The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET acts as 
voltage-vaiable resistor between differential input terminals of opamp. 
Resistance variation is linear with voltage over several decades of 
resistance, to give excellent electronic gain control. Values of resistors 
depend on opamp used."  --"FET Databook", National Semiconductor, 1977, p. 
6-26 -- 6-36.

Comments on this?  Could that be done that simply?  Or what am I missing here?

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From somnium7 at gmail.com  Sat Apr 12 20:52:59 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 12 Apr 2008 14:52:59 -0400
Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
	changes from Logan for 04/12/2008
In-Reply-To: <200804121157.34929.rtellason@verizon.net>
References: <BAY110-W16E31BCB7E0C919F811979C1EE0@phx.gbl>
	<200804121157.34929.rtellason@verizon.net>
Message-ID: <916920440804121152r381cc3bam362f83974788ff74@mail.gmail.com>

Same with me, I can drive to Baltimore in 4 hours and would have if
I'd known this was happening...

Count me in for the next one!

Mike

On Sat, Apr 12, 2008 at 11:57 AM, Roy J. Tellason <rtellason at verizon.net> wrote:

>  (Big snip...)
>
>  Oh my.  Too bad this has to happen just now,  as this one I could actually
>  (maybe) get to.   I guess I'll just have to hope that next time works
>  better...
>
>  --
>  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  ablest -- form of life in this section of space,  a critter that can
>  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  -
>  Information is more dangerous than cannon to a society ruled by lies. --James
>  M Dakin
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From somnium7 at gmail.com  Sat Apr 12 21:00:28 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Sat, 12 Apr 2008 15:00:28 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804121318.37275.rtellason@verizon.net>
References: <200804121318.37275.rtellason@verizon.net>
Message-ID: <916920440804121200o375977e9v6732fc017b72fde7@mail.gmail.com>

I think I have seen something similar in a schematic for an old audio
compressor.

The simplest VCa out there is the Yamaha single transistor design. I
think you can find details about it on Mr. Haible's website.

Using an FET optocoupler is also a simple VCA solution.

Mike

On Sat, Apr 12, 2008 at 1:18 PM, Roy J. Tellason <rtellason at verizon.net> wrote:
> I've got this "Modern Electronic Circuits Reference Manual" I acquired
>  recently,  not all that modern since it was published in 1980,  but I started
>  browsing it anyhow...
>
>  There's one circuit I ran across that I'm wondering about,  never saw it
>  actually used anywhere and I don't know how well this would work,  so I
>  figured I'd toss it out for you guys to pick apart.
>
>  It's a very simple circuit,  really.  An op amp inverting amplifier,  one
>  resistor going from the non-inverting input to ground,  one input resistor,
>  and one feedback resistor.  And,  a JFET connected between the two input
>  terminals with the gate lead labeled as being the gain input.
>
>  The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET acts as
>  voltage-vaiable resistor between differential input terminals of opamp.
>  Resistance variation is linear with voltage over several decades of
>  resistance, to give excellent electronic gain control. Values of resistors
>  depend on opamp used."  --"FET Databook", National Semiconductor, 1977, p.
>  6-26 -- 6-36.
>
>  Comments on this?  Could that be done that simply?  Or what am I missing here?
>
>  --
>  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  ablest -- form of life in this section of space,  a critter that can
>  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  -
>  Information is more dangerous than cannon to a society ruled by lies. --James
>  M Dakin
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From lanterma at ece.gatech.edu  Sat Apr 12 21:25:13 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sat, 12 Apr 2008 15:25:13 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804121318.37275.rtellason@verizon.net>
References: <200804121318.37275.rtellason@verizon.net>
Message-ID: <BE3671A2-EAD3-455A-9F4C-100D4B4B7868@ece.gatech.edu>


On Apr 12, 2008, at 1:18 PM, Roy J. Tellason wrote:

> There's one circuit I ran across that I'm wondering about,  never  
> saw it
> actually used anywhere and I don't know how well this would work,   
> so I
> figured I'd toss it out for you guys to pick apart.
>
> It's a very simple circuit,  really.  An op amp inverting  
> amplifier,  one
> resistor going from the non-inverting input to ground,  one input  
> resistor,
> and one feedback resistor.  And,  a JFET connected between the two  
> input
> terminals with the gate lead labeled as being the gain input.


There's various variable gain amps with JFETs in the input circuitry  
of the Buchla timbre generators (see the Music Easel and 259  
schematics on Magnus's site). I never got around to fully figuring  
them out.

Also see http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/transistors/AN-32.pdf

- Aaron


From batzman-nr at all-electric.com  Sat Apr 12 21:53:06 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Sun, 13 Apr 2008 05:23:06 +0930
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804121318.37275.rtellason@verizon.net>
Message-ID: <5.1.0.14.2.20080413050410.04750e98@mail.all-electric.com>

Y-ellow Roy 'n' all.

At 01:18 PM 4/12/2008 -0400, Roy J. Tellason wrote:

>It's a very simple circuit,  really.  An op amp inverting amplifier,  one
>resistor going from the non-inverting input to ground,  one input resistor,
>and one feedback resistor.  And,  a JFET connected between the two input
>terminals with the gate lead labeled as being the gain input.

I can't remember where I saw something similar (If I understood the 
description correctly) recently. I've seen similar before though with a pot 
or trim pot instead of a FET.

The problem here as I understand it is that it relies on the common mode of 
the Op-Amp. Which means the attenuation can never be 100%. But assuming it 
could be trimmed and/or matched, might be useful for a VCF perhaps. Or a 
compander. The thing to note here is that it is literally "GAIN" of the 
op-amp you are messing with. When the signal on both inputs are equal, in 
theory they cancel out. But for a number of reasons this will never be 
perfect so expect some leakage.

As an added advantage though, it is possible to modify this kind of scheme 
to provide variable gain in both inverting and non inverting directions. I 
can't remember the exact circuit off the top of my head but I'd seen this 
done with a pot. Such that in the centre the gain was a theoretical zero. 
Turn the pot one way and the gain increases inverted and visa versa. One 
wonders whether the same kind of scheme could be used to make a 4 quad 
multiplier on the sly?

If I can remember where I saw the circuit, I'll post it.

Hope this helps.
Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From jhaible at debitel.net  Sat Apr 12 22:49:13 2008
From: jhaible at debitel.net (JH.)
Date: Sat, 12 Apr 2008 22:49:13 +0200
Subject: [sdiy] JH PCBs 
Message-ID: <000501c89cde$ab6fc200$0400a8c0@jhsilent>

Hi,

I have severe computer problems *again*.

I burned the second expensive fan-less computer PSU within a few weeks, 
apparently because of a sporatic fault on the main board and the PSU not 
being short circuit protected.

I have now bought a cheap standard PSU and (obviously) managed to get the 
computer running - only for how long, no one knows.

I'll buy a new PC soon, I guess.

Anyway - if anybody is waiting for email reply, or, more important, for 
shipping of paid PCBs, please don't get angry. There may be some unexpected 
delays. It's just a few out of _many_, but you may be one of the few.

Thanks for understanding.

The good news is: I'll use the time when the computer is down for soldering. 
Still have the 2nd Frequency Shifter prototype to do before I can send out 
all the FS-1a PCBs.
And I'll build the second half of the String Filter.
The first half (20 bands out of 40), already sounds awesome (to me), even 
better than the one I've built a few years ago. You will *love* this, I'm 
sure!

JH. 



From robert.lorentz at gmail.com  Sat Apr 12 22:57:26 2008
From: robert.lorentz at gmail.com (Robert Lorentz)
Date: Sat, 12 Apr 2008 16:57:26 -0400
Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
	changes from Logan for 04/12/2008
In-Reply-To: <916920440804121152r381cc3bam362f83974788ff74@mail.gmail.com>
References: <BAY110-W16E31BCB7E0C919F811979C1EE0@phx.gbl>
	<200804121157.34929.rtellason@verizon.net>
	<916920440804121152r381cc3bam362f83974788ff74@mail.gmail.com>
Message-ID: <225813c30804121357x25fb285are2fd40827ea50698@mail.gmail.com>

I also had no idea this was going on and would have come out to it!
How exciting.  I'm located in Northern VA so this is as close as I can
ask for..

Can whoever's organizing this make it more public next time or maybe
add me to a list regarding it?  Would love some more info

Robert

On Sat, Apr 12, 2008 at 2:52 PM, mike ruberto <somnium7 at gmail.com> wrote:
> Same with me, I can drive to Baltimore in 4 hours and would have if
>  I'd known this was happening...
>
>  Count me in for the next one!
>
>  Mike
>
>
>
>  On Sat, Apr 12, 2008 at 11:57 AM, Roy J. Tellason <rtellason at verizon.net> wrote:
>
>  >  (Big snip...)
>  >
>  >  Oh my.  Too bad this has to happen just now,  as this one I could actually
>  >  (maybe) get to.   I guess I'll just have to hope that next time works
>  >  better...
>  >
>  >  --
>  >  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  >  ablest -- form of life in this section of space,  a critter that can
>  >  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  >  -
>  >  Information is more dangerous than cannon to a society ruled by lies. --James
>  >  M Dakin
>  >
>  >  _______________________________________________
>  >  Synth-diy mailing list
>  >  Synth-diy at dropmix.xs4all.nl
>  >  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>  >
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From jmahoney at gate.net  Sun Apr 13 02:52:40 2008
From: jmahoney at gate.net (John Mahoney)
Date: Sat, 12 Apr 2008 20:52:40 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <916920440804121200o375977e9v6732fc017b72fde7@mail.gmail.co
 m>
References: <200804121318.37275.rtellason@verizon.net>
	<916920440804121200o375977e9v6732fc017b72fde7@mail.gmail.com>
Message-ID: <200804130051.m3D0pqNt018719@dropmix.xs4all.nl>

At 03:00 PM 4/12/2008, mike ruberto wrote:

>The simplest VCa out there is the Yamaha single transistor design. I
>think you can find details about it on Mr. Haible's website.

I was thinking it was a Korg circuit. High control voltage 
feedthrough is it's main problem, if memory serves.


>Using an FET optocoupler is also a simple VCA solution.

How about using a Vactrol? (I know they are slow, but aside from that?)

John 


-- 
No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.13/1375 - Release Date: 4/12/2008 11:32 AM




From guitaricon at comcast.net  Sun Apr 13 04:54:02 2008
From: guitaricon at comcast.net (jeff brown)
Date: Sat, 12 Apr 2008 22:54:02 -0400
Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
	changes from Logan for 04/12/2008
Message-ID: <002c01c89d11$a26b3940$0302a8c0@jeff>


----- Original Message ----- 
From: "jeff brown" <guitaricon at comcast.net>
To: "Logan Mitchell Sr" <prowlerraven32 at hotmail.com>
Sent: Saturday, April 12, 2008 9:25 PM
Subject: Re: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location 
changes from Logan for 04/12/2008


> Dang. I was out all day and just got this.  I live about 20 minutes from 
> there!
>
> Jeff
>
> ----- Original Message ----- 
> From: "Logan Mitchell Sr" <prowlerraven32 at hotmail.com>
> To: <fvanaman at gadgetland.net>
> Cc: <ronwest at gmail.com>; <davevosh at aol.com>; 
> <synth-diy at dropmix.xs4all.nl>; <dgrickert at hotmail.com>; 
> <gregae at comcast.net>; <analogue at hyperreal.org>
> Sent: Saturday, April 12, 2008 11:25 AM
> Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location 
> changes from Logan for 04/12/2008
>
>
>>
>> 04/12/2008
>>
>> Hi Frank. There's been a location & time change. We'll now meet at the 
>> Golden Corral Restaurant on Chesapeake Drive at 2:00 pm today (Golden 
>> Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 
>> (410) 590-0270, 
>> (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02). 
>>  ).
>>
>> The manager was nice enough to provide us with a room that has electrical 
>> outlets for us to plug our stuff up. See the msg below that I sent to 
>> Dave VOSHyesterday. I may leave at little early to make some stops along 
>> the way. My cellphone number is 410-258-1875 & my pager number 
>> w/voice-mail is 1-800-815-5929. I'll notify the rest of the group. Hope 
>> to see you there. Ask for Tony the manager & I'll ask him to direct you 
>> to the room which we'll have the use of from 2:00 to 4:00 pm today. 
>> Thanks.
>>
>>
>> Logan
>>
>>
>> RE: Baltimore SDIY Meet & Greet Proposal from Logan?
>>
>>
>> From:
>> Logan Mitchell Sr (prowlerraven32 at hotmail.com)
>>
>>
>> Sent:
>> Fri 4/11/08 5:57 PM
>>
>>
>> To:
>> davevosh at aol.com
>>
>>
>> Dave
>>
>> The capability to dial my pager number from a payphone was taken away 
>> years ago. I asked them about us setting up in the booths but they have 
>> no electrical outlets in the booths. We may have to look for another 
>> location such as a library unless you still want to meet there and hope 
>> for the magic electric outlet to show up in another part of the diner. 
>> GOOD NEWS - Here's a better location that I go to with the family, Golden 
>> Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 
>> (410) 590-0270, 
>> (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02). 
>> I just talked to Tony who is the manager at
>>
>> this location. I explained to him what we will be doing & that we need an 
>> outlet. He has a room that we can use from 2:00 pm to 4:00 pm as long as 
>> we are there by 2:00 pm tomorrow. I told him that we'll see him there 
>> tomorrow if you're for it, so bring your electronics. I also told him 
>> that we will be using headphones. Let me know what you think. This 
>> location is 2 blocks from Ritchie Highway.
>>
>> Logan
>>
>>
>>> From: fvanaman at gadgetland.net
>>> To: prowlerraven32 at hotmail.com
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>> Date: Sat, 12 Apr 2008 10:28:35 -0400
>>>
>>> 'morning--
>>>
>>> Looks like today's other festivities should be done in time for me to 
>>> make
>>> it down. I'm just about to go out a few hours - but was just wondering
>>> whether you settled on a more definite time this afternoon (and whether 
>>> or
>>> not it was still at the Mountain Road Double-T).
>>>
>>> I'm forwarding a copy to Jeff to see if he might be able to make it...
>>>
>>> Frank
>>>
>>> -----Original Message-----
>>> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
>>> Sent: Thursday, April 10, 2008 10:27 AM
>>> To: fvanaman at gadgetland.net
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>>
>>>
>>> Hi Frank. If you can make it let me know around 5:00 pm on Saturday. You 
>>> can
>>> call me on my pager with voice-mail at 1-800-815-5929. This system is
>>> limited to a 30 second recording time per voice-mail so if it cuts off 
>>> just
>>> call right back to leave another message. Leave me a callback number 
>>> too.
>>> Thanks & I'll keep you posted if you can't make it. Bring Jeff with you 
>>> if
>>> you can.
>>>
>>> Logan
>>> ________________________________
>>>
>>> From: fvanaman at gadgetland.net
>>> To: prowlerraven32 at hotmail.com
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>> Date: Thu, 10 Apr 2008 09:47:03 -0400
>>>
>>>
>>>
>>>
>>>
>>> 'morning--
>>>
>>>
>>>
>>> Meeting (and eating) at a diner seems entirely appropriate for Synth
>>> D-I-Y'ers! :-) The Mountain Road Double-T would be cool. I'm 
>>> particularly
>>> fond of the Double-T north of Whitemarsh on Route 1, and sometimes meet 
>>> up
>>> with JeffK ('analoguejeff' on AH) over there.
>>>
>>>
>>>
>>> My Saturday is very full in the afternoon, and involves trundling my mom 
>>> to
>>> a couple things (which expands the time needed considerably), and also a
>>> couple of already-arranged house viewings, so I'm not sure I'll be done 
>>> in
>>> time for this one.
>>>
>>>
>>>
>>> Keep me posted, though, and I'll try my best,
>>>
>>>
>>>
>>> Frank
>>>
>>>
>>>
>>> ________________________________
>>>
>>> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
>>> Sent: Wednesday, April 09, 2008 10:37 AM
>>> To: fvanaman at gadgetland.net; davevosh at aol.com; gregae at comcast.net;
>>> alfred.pear at gmail.com; dgrickert at hotmail.com; 
>>> prowlerraven32 at hotmail.com;
>>> ronwest at gmail.com
>>> Subject: Baltimore SDIY Meet & Greet Proposal from Logan
>>>
>>>
>>> 04/08/2008
>>>
>>> Hello to all & welcome to the first informal meeting of the newly formed
>>> Baltimore SDIY (Synthesizer Do It Yourself) Group. My name is Logan 
>>> Mitchell
>>> Sr and in November of 2007 I decided that it was time to try & form an 
>>> SDIY
>>> group here in Baltimore since all of the other groups seem to be located 
>>> in
>>> the upper Northeast or Northwest part of the country. Due to the 
>>> distances &
>>> today's increasing gas prices I find it difficult to attend any of these
>>> meetings. I really didn't know if anyone else would be interested in 
>>> doing
>>> something like this so I was afraid that it might not work but that has 
>>> now
>>> changed because you have decided to particpate in this endeavor of mine 
>>> for
>>> which I am very grateful.
>>>
>>> I am hoping that more s-d-i-yers join the group. For our first 
>>> face-to-face
>>> meeting I would like to propose that we meet at a restaurant which has a
>>> separate room similar to what the Double T Diner has. Here's a location 
>>> that
>>> closes off its Dining Room from 2:00 to 4:30pm but only on Mon thru 
>>> Fri -
>>> Double T Diner Co 1 Mountain Rd, Pasadena, MD 21122 (410) 766-9669
>>> (http://localsearch.live.com/localsearch/Details.aspx?what=diners&where=Glen
>>> +Burnie%2c+MD&tab=businessinfo&lid=YN404x7302805&qt=yp&s_cid=ansPhBkYp02&FOR
>>> M=LLDP).
>>>
>>> If you know of a better centralized location that's easy to get to then
>>> please let me know because I want everyone to be able to get there 
>>> easily &
>>> economically as well.
>>>
>>> Since I live in Northwest Baltimore 2 blocks from Pimlico Racetrack &
>>> everyone else lives in White Marsh and Upper Marlboro, it seems like 
>>> this
>>> may be a good central location for us to meet on a temporary or 
>>> permanent
>>> basis. Let me know what you think and maybe we can do a Meet & Greet 
>>> this
>>> Saturday (04/12/2008) say around 5:00 or 6:00 pm. Thanks.
>>>
>>> Logan
>>>
>>> Current members:
>>> Logan Mitchell Sr ProwlerRaven32 at hotmail.com (Baltimore MD) Alfred PEAR
>>> Alfred.Pear at gmail.com (Baltimore MD) Frank VANAMAN 
>>> FVanaman at gadgetland.net
>>> Dave VOSH DaveVosh at aol.com (Upper Marlboro MD) Ron WEST 
>>> Ron.West at gmail.com
>>> (White Marsh MD) Greg KIST GregAE at comcast.net (Columbia MD) David 
>>> RICKERT
>>> DGRickert at hotmail.com (Washington DC)
>>>
>>>
>>> ________________________________
>>>
>>> Get in touch in an instant. Get Windows Live Messenger now.
>>>
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 
>>> 4/9/2008
>>> 7:10 AM
>>>
>>>
>>>
>>> No virus found in this outgoing message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 
>>> 4/9/2008
>>> 4:20 PM
>>>
>>> _________________________________________________________________
>>> Use video conversation to talk face-to-face with Windows Live Messenger.
>>> http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGLM_WL
>>> _Refresh_messenger_video_042008
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 
>>> 4/9/2008
>>> 4:20 PM
>>>
>>>
>>> No virus found in this outgoing message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.12/1374 - Release Date: 
>>> 4/11/2008
>>> 4:59 PM
>>>
>>>
>>
>> _________________________________________________________________
>> Going green? See the top 12 foods to eat organic.
>> http://green.msn.com/galleries/photos/photos.aspx?gid=164&ocid=T003MSN51N1653A
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From richard.e.johnson at gmail.com  Sun Apr 13 07:14:39 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Sun, 13 Apr 2008 01:14:39 -0400
Subject: [sdiy] Greetings
In-Reply-To: <001701c89ce0$52e1db80$82c2fea9@tim3>
References: <be8b34180804100630ybe5d554l6f548e913dd3dd77@mail.gmail.com>
	<6EE8BAAD-0705-11DD-B49F-000393A85F9E@ntlworld.com>
	<be8b34180804101234j1db738a2wbf0fcf53888a67fb@mail.gmail.com>
	<003601c89bda$b7c3d6e0$0d8bfe04@tim3>
	<be8b34180804111423r45ab5b6cs69aa7c8c0643ef0c@mail.gmail.com>
	<001701c89ce0$52e1db80$82c2fea9@tim3>
Message-ID: <be8b34180804122214i1ab16534ibf3dac74f3fbcee6@mail.gmail.com>

That's cool, but the specifcs of you LNA (ALN) on that page are
missing. The link 404's! :(

I'm looking for a sound (a Juno Sound?) like the bass note from Van
Halen's "Jump"

Ideas?

On Sat, Apr 12, 2008 at 5:01 PM, Tim Daugard <daugard at sprintmail.com> wrote:
> Ric,
>
>
>  > Is your primary oscillator your bass guitar? It didn't seem that you
>  > had a VCO circuit listed (other than the sine tester).
>
>  Absoulutely. I figured my bass was a far better signal source than trying to brew a VCO
>  and then figure out how I was going to play it while still playing bass.
>
>
>  > If it's true, that's so strange as my first project is trying to
>  > convert the coil-pickup AC output of a bass-guitar-like instrument
>  > into a simple analog synth by using the output as the primary
>  > oscillator.
>
>  LNA -> ?? -> Amp Driver
>
>  http://home.earthlink.net/~synthfred/patch/chp16c.htm
>
>  Is a page covering my mini-system. It can be built for $30 to $40. The low price is using
>  parts you have or ordering parts from Mouser. The high price is using radio shack parts.
>
>  What kind of sound are you looking for? I have created over a 100 different sounds using
>  my bass - everything from an organ, wood wind, screaming guitar (two octaves up) to 80's
>  synth pads.
>
>  > Hmmmm...
>
>  That's what I said. The three things keeping me from build a synth years agos was: The
>  keyboard, the cost of connectors and the cost of potentiometers. I decided not to use the
>  first and dound low cost ways to solve the other two problems. Check out the parts pages
>  in the construction section of my web-book.
>
>  Tim
>
>


From aym-htnys at teaser.fr  Sun Apr 13 09:54:27 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Sun, 13 Apr 2008 09:54:27 +0200
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804130051.m3D0pqNt018719@dropmix.xs4all.nl>
References: <200804121318.37275.rtellason@verizon.net>
	<916920440804121200o375977e9v6732fc017b72fde7@mail.gmail.com>
	<200804130051.m3D0pqNt018719@dropmix.xs4all.nl>
Message-ID: <20080413075427.GA4544@aym.net2.nerim.net>

On 2008-04-12 20:52 -0400, John Mahoney wrote:
> At 03:00 PM 4/12/2008, mike ruberto wrote:
>
>> The simplest VCa out there is the Yamaha single transistor design. I
>> think you can find details about it on Mr. Haible's website.
>
> I was thinking it was a Korg circuit. High control voltage
> feedthrough is it's main problem, if memory serves.

It's noisy too. On paper, it's a very bad VCA. In practice, it
makes a wonderful audio VCA if you can live with the thump on fast
envelopes.

>> Using an FET optocoupler is also a simple VCA solution.
>
> How about using a Vactrol? (I know they are slow, but aside from
> that?)

The light-dependent resistor exhibits a memory effect. The same CV
will not yield the same resistance depending on what CV you have
applied for the past minute. It's hard to use for control voltages
if any kind of precision is needed.

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From pfperry at melbpc.org.au  Sun Apr 13 10:20:15 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 13 Apr 2008 18:20:15 +1000
Subject: [sdiy] Simple VCA?
In-Reply-To: <20080413075427.GA4544@aym.net2.nerim.net>
Message-ID: <000301c89d3f$345c64f0$8501a8c0@ice9>

Certainly, it's worth distinguishing between simple VCAs that are 'good
enough for audio' and ones of high precision.
But I doubt the latter exist, anyway.

Incidentally, I suspect that the MS20 'too simple' VCA requires selected
transistors..

Paul Perry (Melbourne Australia)




From debus at cityweb.de  Sun Apr 13 10:37:49 2008
From: debus at cityweb.de (Ingo Debus)
Date: Sun, 13 Apr 2008 10:37:49 +0200
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804121318.37275.rtellason@verizon.net>
References: <200804121318.37275.rtellason@verizon.net>
Message-ID: <C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>


Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
> It's a very simple circuit,  really.  An op amp inverting  
> amplifier,  one
> resistor going from the non-inverting input to ground,  one input  
> resistor,
> and one feedback resistor.  And,  a JFET connected between the two  
> input
> terminals with the gate lead labeled as being the gain input.
>
> The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET  
> acts as
> voltage-vaiable resistor between differential input terminals of  
> opamp.
> Resistance variation is linear with voltage over several decades of
> resistance, to give excellent electronic gain control. Values of  
> resistors
> depend on opamp used."  --"FET Databook", National Semiconductor,  
> 1977, p.
> 6-26 -- 6-36.

I just don't understand how this would work. When the feedback loop  
is working correctly there's virtually zero voltage between the two  
inputs of the opamp. There would be no current through a resistor,  
variable or not, between the two inputs, so this resistor doesn't do  
anything.
What am I missing?

Ingo


From pfperry at melbpc.org.au  Sun Apr 13 11:01:44 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 13 Apr 2008 19:01:44 +1000
Subject: [sdiy] Simple VCA?
In-Reply-To: <C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
Message-ID: <000501c89d44$ff7b8080$8501a8c0@ice9>

I don't know exactly what is going on either, Ingo, but think about this - 
Putting an infinite resistor across the inputs would do nothing.
But imagine if you put a zero ohm resistor across there - that would
certainly shut off the gain.
So the two extreme cases do something!
The question now is to make it linear ;D

paul perry Melbourne Australia 
-----Original Message-----
I just don't understand how this would work. When the feedback loop  
is working correctly there's virtually zero voltage between the two  
inputs of the opamp. There would be no current through a resistor,  
variable or not, between the two inputs, so this resistor doesn't do  
anything.
What am I missing?




From sounddoctorin at imt.net  Sun Apr 13 11:04:19 2008
From: sounddoctorin at imt.net (Bob Weigel)
Date: Sun, 13 Apr 2008 03:04:19 -0600
Subject: [sdiy] Simple VCA?
In-Reply-To: <C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
References: <200804121318.37275.rtellason@verizon.net>
	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
Message-ID: <4801CC93.8000706@imt.net>

I don't have time to look at the circuit right now...but I'd have to 
assume that this is perhaps in an inverting amplifier circuit with a 
resistance between the invert input and signal source?  If so then this 
resistance becomes a pathway to ground other than the output's effect on 
the f/b resistance and thus proportionalizes with the input bias current 
requirement. Remember, usually when one considers an op amp design, they 
trivialize and make the assumption that the inputs have infinite 
resistance.  And for most conventional deisgnes we deal with, this 
works. Or..  ...here..let me explain it this way. 

Take it to the logical extreme.  What happens if the resistance is 
zero?  Will you still have an inverting amplifier then?   no of course 
not.  If the non-inv. is grounded and there is a resistance that is low 
between it and the invert, then it will have a large effect on the 
current that would be otherwise biasing the input of that amp.

Hence the amount of resistance needed to provide a certain amount of 
gain will vary with the input characteristic of the op amp in such a 
design.  -bob

Ingo Debus wrote:

>
> Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
>
>> It's a very simple circuit,  really.  An op amp inverting  
>> amplifier,  one
>> resistor going from the non-inverting input to ground,  one input  
>> resistor,
>> and one feedback resistor.  And,  a JFET connected between the two  
>> input
>> terminals with the gate lead labeled as being the gain input.
>>
>> The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET  
>> acts as
>> voltage-vaiable resistor between differential input terminals of  opamp.
>> Resistance variation is linear with voltage over several decades of
>> resistance, to give excellent electronic gain control. Values of  
>> resistors
>> depend on opamp used."  --"FET Databook", National Semiconductor,  
>> 1977, p.
>> 6-26 -- 6-36.
>
>
> I just don't understand how this would work. When the feedback loop  
> is working correctly there's virtually zero voltage between the two  
> inputs of the opamp. There would be no current through a resistor,  
> variable or not, between the two inputs, so this resistor doesn't do  
> anything.
> What am I missing?
>
> Ingo
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>


From rtellason at verizon.net  Sun Apr 13 13:53:53 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sun, 13 Apr 2008 07:53:53 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
References: <200804121318.37275.rtellason@verizon.net>
	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
Message-ID: <200804130753.53414.rtellason@verizon.net>

On Sunday 13 April 2008 04:37, Ingo Debus wrote:
> Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
> > It's a very simple circuit,  really.  An op amp inverting amplifier,  one
> > resistor going from the non-inverting input to ground,  one input 
> > resistor,  and one feedback resistor.  And,  a JFET connected between the
> > two input terminals with the gate lead labeled as being the gain input.
> >
> > The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET
> > acts as voltage-vaiable resistor between differential input terminals of
> > opamp. Resistance variation is linear with voltage over several decades of
> > resistance, to give excellent electronic gain control. Values of
> > resistors depend on opamp used."  --"FET Databook", National
> > Semiconductor,  1977, p. 6-26 -- 6-36.
>
> I just don't understand how this would work. When the feedback loop
> is working correctly there's virtually zero voltage between the two
> inputs of the opamp. There would be no current through a resistor,
> variable or not, between the two inputs, so this resistor doesn't do
> anything. What am I missing?

That's what I'm wondering,  too...    :-)

Still,  in troubleshooting gear over the years,  one handy test that I've 
found when you have an op amp that has an output sitting on one of the rails 
is to short the two inputs together. If it settles out in the middle then the 
problem is with some earlier stage,  if not then probably a bad chip (most of 
the ones I've seen fail do so with the ouput at one rail or the other).

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From rtellason at verizon.net  Sun Apr 13 13:56:13 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sun, 13 Apr 2008 07:56:13 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <4801CC93.8000706@imt.net>
References: <200804121318.37275.rtellason@verizon.net>
	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
	<4801CC93.8000706@imt.net>
Message-ID: <200804130756.13865.rtellason@verizon.net>

On Sunday 13 April 2008 05:04, Bob Weigel wrote:
> I don't have time to look at the circuit right now...but I'd have to
> assume that this is perhaps in an inverting amplifier circuit with a
> resistance between the invert input and signal source?

No.  The stuff you quoted below describes it.  Three resistors,  input, 
feedback,  and non-inverting input to ground.  The FET goes between the two 
inputs of the chips.

> If so then this resistance becomes a pathway to ground other than the
> output's effect on the f/b resistance and thus proportionalizes with the
> input bias current requirement. Remember, usually when one considers an op
> amp design, they trivialize and make the assumption that the inputs have
> infinite resistance.  And for most conventional deisgnes we deal with, this
> works. Or..  ...here..let me explain it this way.
>
> Take it to the logical extreme.  What happens if the resistance is
> zero?  Will you still have an inverting amplifier then?   no of course
> not.  If the non-inv. is grounded and there is a resistance that is low
> between it and the invert, then it will have a large effect on the
> current that would be otherwise biasing the input of that amp.
>
> Hence the amount of resistance needed to provide a certain amount of
> gain will vary with the input characteristic of the op amp in such a
> design.  -bob

I'm gonna have to build this on a breadboard some time and try it out,  I 
think...

> Ingo Debus wrote:
> > Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
> >> It's a very simple circuit,  really.  An op amp inverting
> >> amplifier,  one
> >> resistor going from the non-inverting input to ground,  one input
> >> resistor,
> >> and one feedback resistor.  And,  a JFET connected between the two
> >> input
> >> terminals with the gate lead labeled as being the gain input.
> >>
> >> The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET
> >> acts as
> >> voltage-vaiable resistor between differential input terminals of  opamp.
> >> Resistance variation is linear with voltage over several decades of
> >> resistance, to give excellent electronic gain control. Values of
> >> resistors
> >> depend on opamp used."  --"FET Databook", National Semiconductor,
> >> 1977, p.
> >> 6-26 -- 6-36.
> >
> > I just don't understand how this would work. When the feedback loop
> > is working correctly there's virtually zero voltage between the two
> > inputs of the opamp. There would be no current through a resistor,
> > variable or not, between the two inputs, so this resistor doesn't do
> > anything.
> > What am I missing?
> >
> > Ingo
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From dragon.servicing at googlemail.com  Sun Apr 13 14:19:04 2008
From: dragon.servicing at googlemail.com (dragon.servicing)
Date: Sun, 13 Apr 2008 13:19:04 +0100
Subject: [sdiy] youtube with Polymoog  (and Bach Music ) 
In-Reply-To: <4801CC93.8000706@imt.net>
References: <200804121318.37275.rtellason@verizon.net>	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
	<4801CC93.8000706@imt.net>
Message-ID: <4801FA38.2000908@googlemail.com>

Hi,
just thought you might be interested in this clip from the early 1980's 
that was mentioned on one of the other music lists I am on.

http://www.youtube.com/watch?v=NeGskVvgbjQ&feature=related

  featuring Rosalyn Tureck on different instruments including a Polymoog 
   ( I think )
regards Peter


From ebrombaugh at earthlink.net  Sun Apr 13 16:33:20 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Sun, 13 Apr 2008 07:33:20 -0700
Subject: [sdiy] Simple VCA?
In-Reply-To: <C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
References: <200804121318.37275.rtellason@verizon.net>
	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
Message-ID: <480219B0.6060705@earthlink.net>

Ingo Debus wrote:
> 
> Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
>> It's a very simple circuit,  really.  An op amp inverting amplifier,  one
>> resistor going from the non-inverting input to ground,  one input 
>> resistor,
>> and one feedback resistor.  And,  a JFET connected between the two input
>> terminals with the gate lead labeled as being the gain input.
>>
>> The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET acts as
>> voltage-vaiable resistor between differential input terminals of opamp.
>> Resistance variation is linear with voltage over several decades of
>> resistance, to give excellent electronic gain control. Values of 
>> resistors
>> depend on opamp used."  --"FET Databook", National Semiconductor, 
>> 1977, p.
>> 6-26 -- 6-36.
> 
> I just don't understand how this would work. When the feedback loop is 
> working correctly there's virtually zero voltage between the two inputs 
> of the opamp. There would be no current through a resistor, variable or 
> not, between the two inputs, so this resistor doesn't do anything.
> What am I missing?

Remember that the ideal op-amp we use to understand how feedback 
circuits work is a fiction. In reality the open-loop gain of a real 
op-amp is finite, so there must be some small voltage difference between 
the + and - inputs in order for the output voltage to change. This 
circuit takes advantage of that by shorting out that small voltage to 
cut the output voltage of the amplifier to zero.

As mentioned elsewhere in this thread, the actual results of this are 
going to depend to a large extent on the type of op-amp you're using, 
how it's biased and the topology of the feedback network you've built 
around it. Put more simply, this type of VCA is going to be hard to 
control. From a mass-production standpoint it may not even be 
manufacturable without hand-selected parts, and thus in high volume 
applications isn't even cheaper than other topologies.

Eric


From beschaving at gmail.com  Sun Apr 13 16:46:35 2008
From: beschaving at gmail.com (beschaving at gmail.com)
Date: Sun, 13 Apr 2008 16:46:35 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <52706.38.112.225.84.1207594596.squirrel@www.eventualdecline.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<52706.38.112.225.84.1207594596.squirrel@www.eventualdecline.com>
Message-ID: <001D1088-BA12-481B-BAE6-D6870D2B5A9C@gmail.com>

On Apr 7, 2008, at 8:56 PM, Ben Lincoln wrote:

> If I were going to do something like that, I would definitely use the
> latter type of approach - make some sort of adapter between the  
> factory
> patch panel and something else. That way you won't end up physically
> damaging the real connectors. You could also use it as an  
> opportunity to
> *not* make connections to potentially dangerous connectors (power,  
> etc)
> that shouldn't be routed to the other pins.

Yeah, definitely. I'll be interfacing with a Serge modular that I'd  
prefer not to damage or alter in any way, so I'll run a cable snake  
from various modules on the Serge front panel into my mess-up breakout  
box. This way I can also make various types of breakout boxes with  
weird connectors on them, and switch between them just by plugging  
another one in...


>
>
> On Mon, April 7, 2008 11:24 am, |||||||||| |||||||||| said:
>> Hi everyone,
>>
>> I'm currently thinking about alternative ways of making connections  
>> on
>> a modular synth, particularly of the primitive, somewhat random kind.
>> For example, German Synthi AKS improviser Thomas Lehn sticks bits of
>> metal in the Synthi "Prestopatch" slot and wiggles it around, to
>> short-circuit between various modules and make all kinds of sudden
>> complex noises...This is what I'm into as well. (It doesn't seem to
>> harm his Synthi, by the way).
>>
>> I'd love to hear about other ways that people are "mechanically"
>> interfacing with their synths. I vaguely remember seeing some design
>> that just had a number of metal nails sticking up, for example, that
>> one would either touch or clamp crocodile cables to.
>> I also seem to remember something with a metal ball rolling around
>> another bed of nails?
>>
>> Sorry to jump from lurking to taking up so much bandwidth all of a
>> sudden, by the way...
>>
>> Thank you for any hints, suggestions etc!
>>
>> Alex


From beschaving at gmail.com  Sun Apr 13 17:55:47 2008
From: beschaving at gmail.com (beschaving at gmail.com)
Date: Sun, 13 Apr 2008 17:55:47 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>
	<F35B94AF-1116-408F-8BEC-31A2D6276540@ntlworld.com>
Message-ID: <2D25CB18-0E3B-411A-9213-1BDCBFAABBC1@gmail.com>

That's one of Peter Blasser's Fyrall synths, right?

I like that peg-system, you can use alligator clips for stable  
connections or your fingers for variable resistance. Or worms, yes.


On Apr 7, 2008, at 11:11 PM, Neil Johnson wrote:

> Hi,
>
>> I'd love to hear about other ways that people are "mechanically"
>> interfacing with their synths. I vaguely remember seeing some design
>> that just had a number of metal nails sticking up, for example, that
>> one would either touch or clamp crocodile cables to.
>
> Something like this?:
>
> http://gallery.diy.synth.net/main.php?g2_itemId=868
>
> Yes, it was quite a strange box.  The schematic, too, was, umm,  
> artistic.
>
> Neil
> --
> http://www.njohnson.co.uk
>
>
>



From beschaving at gmail.com  Sun Apr 13 18:21:15 2008
From: beschaving at gmail.com (beschaving at gmail.com)
Date: Sun, 13 Apr 2008 18:21:15 +0200
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <47FB39BD.2010906@bugbrand.co.uk>
References: <de53b7a90804071124h487c0c2dk299619e39c85f77e@mail.gmail.com>	<20080407192312.GA8093@cs.wisc.edu>
	<BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
	<47FB39BD.2010906@bugbrand.co.uk>
Message-ID: <FC7D1D9C-6B38-4EDF-9D3F-64CD9E87284F@gmail.com>

On Apr 8, 2008, at 11:24 AM, Tom Bugs wrote:

> Licked fingers (or maybe just sweaty) or other body parts (ooo-er)  
> will provide much higher resistances! --- earthworms are exactly the  
> same idea, but isn't it a bit cruel?
> -- you can make a patchbay kind of like a cracklebox touchplate --  
> this can be great fun to play.

Has anyone here tried to make their own touchplate controller?

I've seen the Buchla and Serge touchplate keyboards, as well as the  
much smaller Crackle Box one, but how would one DIY one of these?

Is there maybe some company out there that makes custom-designed touch  
plate things on a one-off basis? That would be interesting to find  
out. Kind of Schaeffer does for frontpanels...




>
>
> Needless to say - be careful and aware of what you're doing both for  
> your own health and that of your synth. I've not had any problems  
> myself, but I've certainly felt some electrical flow when I've held  
> patch cables in my mouth!


From keithw at cix.compulink.co.uk  Sun Apr 13 18:26:00 2008
From: keithw at cix.compulink.co.uk (Keith Winstanley)
Date: Sun, 13 Apr 2008 17:26 +0100 (BST)
Subject: [sdiy] Old minimoog oscillator board
Message-ID: <memo.831293@cix.compulink.co.uk>

today, I have mostly been matching transistors for my discrete
minimoog oscillator board.

Keith

http://home.freeuk.net/lowpass



From magnus at rubidium.dyndns.org  Sun Apr 13 18:34:07 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sun, 13 Apr 2008 18:34:07 +0200 (CEST)
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <FC7D1D9C-6B38-4EDF-9D3F-64CD9E87284F@gmail.com>
References: <BAY144-DAV135A203CD53E025C7F982EB3F30@phx.gbl>
	<47FB39BD.2010906@bugbrand.co.uk>
	<FC7D1D9C-6B38-4EDF-9D3F-64CD9E87284F@gmail.com>
Message-ID: <20080413.183407.193190059781567393.cfmd@bredband.net>

From: "beschaving at gmail.com" <beschaving at gmail.com>
Subject: Re: [sdiy] Chaotic/lo-fi patching techniques
Date: Sun, 13 Apr 2008 18:21:15 +0200
Message-ID: <FC7D1D9C-6B38-4EDF-9D3F-64CD9E87284F at gmail.com>

> On Apr 8, 2008, at 11:24 AM, Tom Bugs wrote:
> 
> > Licked fingers (or maybe just sweaty) or other body parts (ooo-er) will provide much higher resistances! --- earthworms are exactly the same idea, but isn't it a bit cruel?
> > -- you can make a patchbay kind of like a cracklebox touchplate -- this can be great fun to play.
> 
> Has anyone here tried to make their own touchplate controller?
> 
> I've seen the Buchla and Serge touchplate keyboards, as well as the much smaller Crackle Box one, but how would one DIY one of these?
> 
> Is there maybe some company out there that makes custom-designed touch plate things on a one-off basis? That would be interesting to find out. Kind of Schaeffer does for frontpanels...

They are not that complex really. There are a few principles but neither of
them is particular hard. The EMS KS keyboard has a particular benefit in that
it does not require direct electrical contact with the finger, since it
measures the capacitance, so they have a nice printed decal over the PCB
layout. It uses standard TTL for scanning using a clever tecnique. This also
include the transpose-keys, which actually is quite cute.

Cheers,
Magnus


From rtellason at verizon.net  Sun Apr 13 18:50:53 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sun, 13 Apr 2008 12:50:53 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <480219B0.6060705@earthlink.net>
References: <200804121318.37275.rtellason@verizon.net>
	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
	<480219B0.6060705@earthlink.net>
Message-ID: <200804131250.53975.rtellason@verizon.net>

On Sunday 13 April 2008 10:33, Eric Brombaugh wrote:
> Ingo Debus wrote:
> > Am 12.04.2008 um 19:18 schrieb Roy J. Tellason:
> >> It's a very simple circuit,  really.  An op amp inverting amplifier, 
> >> one resistor going from the non-inverting input to ground,  one input
> >> resistor, and one feedback resistor.  And,  a JFET connected between the
> >> two input terminals with the gate lead labeled as being the gain input.
> >>
> >> The caption for this reads "VOLTAGE-CONTROLLED GAIN -- 2N5457 FET acts
> >> as voltage-vaiable resistor between differential input terminals of
> >> opamp. Resistance variation is linear with voltage over several decades
> >> of resistance, to give excellent electronic gain control. Values of
> >> resistors depend on opamp used."  --"FET Databook", National
> >> Semiconductor,  1977, p. 6-26 -- 6-36.
> >
> > I just don't understand how this would work. When the feedback loop is
> > working correctly there's virtually zero voltage between the two inputs
> > of the opamp. There would be no current through a resistor, variable or
> > not, between the two inputs, so this resistor doesn't do anything.
> > What am I missing?
>
> Remember that the ideal op-amp we use to understand how feedback
> circuits work is a fiction. In reality the open-loop gain of a real
> op-amp is finite, so there must be some small voltage difference between
> the + and - inputs in order for the output voltage to change. This
> circuit takes advantage of that by shorting out that small voltage to
> cut the output voltage of the amplifier to zero.
>
> As mentioned elsewhere in this thread, the actual results of this are
> going to depend to a large extent on the type of op-amp you're using,
> how it's biased and the topology of the feedback network you've built
> around it. Put more simply, this type of VCA is going to be hard to
> control. From a mass-production standpoint it may not even be
> manufacturable without hand-selected parts, and thus in high volume
> applications isn't even cheaper than other topologies.

The interesting thing about that is that although they specifiy the JFET used 
there they don't seem to specify any particular kind of opamp.  The feedback 
network is about as simple as you can get.  The reason I'm interested in this 
is primarily the simplicity of the circuit, and the lack of need for 
specialized chips that are all too often either unobtainium or way more 
expensive for casual fooling around.

As I'd said earlier,  maybe one of these days I'll get around to breadboarding 
it...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From Stromeko at nexgo.de  Sun Apr 13 19:11:25 2008
From: Stromeko at nexgo.de (ASSI)
Date: Sun, 13 Apr 2008 19:11:25 +0200
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804121318.37275.rtellason@verizon.net>
References: <200804121318.37275.rtellason@verizon.net>
Message-ID: <200804131911.25634.Stromeko@nexgo.de>

On Samstag 12 April 2008, Roy J. Tellason wrote:
> It's a very simple circuit,  really.  An op amp inverting amplifier, 
> one resistor going from the non-inverting input to ground,  one input
> resistor, and one feedback resistor.  And,  a JFET connected between
> the two input terminals with the gate lead labeled as being the gain
> input.

What you have there is a "condensed" version of an adder/subtractor 
circuit.  When the JFET is off, you get just the normal inverting 
amplifier, when it is conducting, you mix the inverted with some 
portion of the non-inverted signal.  In this particular configuration 
the input resistor for the non-inverting input is shared with the 
non-inverting input.  Besides saving a resistor it keeps the voltage 
across the JFET near zero, which presumably helps getting a control law 
that is independent from the input signal (you'd suffer from that if 
the JFET was in the feedback path).



Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Wavetables for the Terratec KOMPLEXER:
http://Synth.Stromeko.net/Downloads.html#KomplexerWaves



From gatkins at blueyonder.co.uk  Sun Apr 13 21:09:19 2008
From: gatkins at blueyonder.co.uk (GRAHAM ATKINS)
Date: Sun, 13 Apr 2008 20:09:19 +0100
Subject: [sdiy] youtube with Polymoog  (and Bach Music ) 
In-Reply-To: <4801FA38.2000908@googlemail.com>
References: <200804121318.37275.rtellason@verizon.net>	<C093A250-09EC-4877-BAB0-65B77F1B5D65@cityweb.de>
	<4801CC93.8000706@imt.net> <4801FA38.2000908@googlemail.com>
Message-ID: <72836FDD-6A7A-4ECC-8B60-A7D6A10A6910@blueyonder.co.uk>

Hi Pete,

It appears to be a Polymoog Keyboard which was a cheaper version of  
the full blown
Polymoog and was more of a preset instrument with limited control IIRC.

Graham

On Apr 13, 2008, at 13:19, dragon.servicing wrote:

> Hi,
> just thought you might be interested in this clip from the early  
> 1980's that was mentioned on one of the other music lists I am on.
>
> http://www.youtube.com/watch?v=NeGskVvgbjQ&feature=related
>
> featuring Rosalyn Tureck on different instruments including a  
> Polymoog   ( I think )
> regards Peter
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>




From gatkins at blueyonder.co.uk  Sun Apr 13 21:13:45 2008
From: gatkins at blueyonder.co.uk (GRAHAM ATKINS)
Date: Sun, 13 Apr 2008 20:13:45 +0100
Subject: [sdiy] Old minimoog oscillator board
In-Reply-To: <memo.831293@cix.compulink.co.uk>
References: <memo.831293@cix.compulink.co.uk>
Message-ID: <2130DC00-4BE0-4563-9C9A-594B9F30E3B8@blueyonder.co.uk>

Thanks Jesse (Keith),

It's a shame most people outside the UK won't appreciate your
joke.........Which was nice !

Graham

On Apr 13, 2008, at 17:26, Keith Winstanley wrote:

> today, I have mostly been matching transistors for my discrete
> minimoog oscillator board.
>
> Keith
>
> http://home.freeuk.net/lowpass
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>




From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 13 21:16:17 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 13 Apr 2008 20:16:17 +0100
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804131250.53975.rtellason@verizon.net>
Message-ID: <000a01c89d9a$de3c0920$42644154@stingo>

> The interesting thing about that is that although they 
> specifiy the JFET used 
> there they don't seem to specify any particular kind of 
> opamp.  The feedback 
> network is about as simple as you can get.

Just found the circuit in the back of an old Teledyne Semiconductor databook
('JFET Design and Application Manual', 1980), which has a small section of
application notes at the end - unfortunately it is very sparse too: the op
amp is shown as a 741; the JFET either 2N4302 or 2N4220; input resistor (on
-ve in) and resistor to ground (on +ve in) are both 510 ohms; feedback
resistor 'RF' not given (useful huh?). No equations or anything, but the
figure caption says: "Electronic gain control utilizing the low offset
voltage of the 741, the JFET will have linear resistance over several
decades".

I'm sure I have seen this somewhere else, but a quick skim of my FET books
didn't uncover it - maybe I'll have another more leisurely peruse.

I agree with Achim that it must be acting as some sort of subtractor, but my
feeble attempt so far at analyzing it hasn't made much sense!

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk






From keithw at cix.compulink.co.uk  Sun Apr 13 21:24:00 2008
From: keithw at cix.compulink.co.uk (Keith Winstanley)
Date: Sun, 13 Apr 2008 20:24 +0100 (BST)
Subject: [sdiy] Old minimoog oscillator board
Message-ID: <memo.832748@cix.compulink.co.uk>

In-Reply-To: <2130DC00-4BE0-4563-9C9A-594B9F30E3B8 at blueyonder.co.uk>
Nice!

;o)


> Thanks Jesse (Keith),
> 
> It's a shame most people outside the UK won't appreciate your
> joke.........Which was nice !
> 
> Graham
> 
> On Apr 13, 2008, at 17:26, Keith Winstanley wrote:
> 
> > today, I have mostly been matching transistors for my discrete
> > minimoog oscillator board.
> >


Keith

http://home.freeuk.net/lowpass



From rdrake at data2action.com  Sun Apr 13 21:32:50 2008
From: rdrake at data2action.com (rdrake)
Date: Sun, 13 Apr 2008 15:32:50 -0400
Subject: =?US-ASCII?B?UkU6IFJlOiBbc2RpeV0gQ2hhb3RpYy9sby1maSBwYXRjaGluZyB0ZWNobmlxdWVz?=
Message-ID: <20080413193250.11863.qmail@mmm1113.verio-web.com>

schemo for a serge capcitance-based design was published in Synapse, now online at: 

http://www.cyndustries.com/synapse/synapse.cfm?pc=39&folder=jan1977&pic=26

courtesy of cyndustries.

bbob

>From: "beschaving at gmail.com" <beschaving at gmail.com>
>Subject: Re: [sdiy] Chaotic/lo-fi patching techniques
>Date: Sun, 13 Apr 2008 18:21:15 +0200
>
>> On Apr 8, 2008, at 11:24 AM, Tom Bugs wrote:
>> 
>> > Licked fingers (or maybe just sweaty) or other
>body parts (ooo-er) will provide much higher
>resistances! --- earthworms are exactly the same
>idea, but isn't it a bit cruel?
>> > -- you can make a patchbay kind of like a
>cracklebox touchplate -- this can be great fun to
>play.
>> 
>> Has anyone here tried to make their own
>touchplate controller?
>> 
>> I've seen the Buchla and Serge touchplate
>keyboards, as well as the much smaller Crackle Box
>one, but how would one DIY one of these?
>> 
>> Is there maybe some company out there that makes
>custom-designed touch plate things on a one-off
>basis? That would be interesting to find out. Kind
>of Schaeffer does for frontpanels...


From music.maker at gte.net  Sun Apr 13 21:38:55 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Sun, 13 Apr 2008 12:38:55 -0700
Subject: [sdiy] Simple VCA?
Message-ID: <200804131938.m3DJctf4029601@linux7.lan>

I don't have any of these publications.

Does it look like this ASCIImatic:


                                FB ?

                       +------\/\/\/\---+
            510R       |                |
                       |  |\            |
    IN *--/\/\/\/---+--+--|-\           |
                    |     |  \          |
                    |     |   \         |   out
                  |-+     |    >--------+----->
                  |       |   /
cont *-/\/\/\/--->|-+     |  /
                    |  +--|+/
          ???       |  |  |/ 
                    +--+
                    |
                    |
                    /
                    \ 510R
                    /
                    \
                    /
                    |
                    |
                  GND




tim102 at tstinchcombe.freeserve.co.uk wrote:
>> The interesting thing about that is that although they 
>> specifiy the JFET used 
>> there they don't seem to specify any particular kind of 
>> opamp.  The feedback 
>> network is about as simple as you can get.
>
>Just found the circuit in the back of an old Teledyne Semiconductor databook
>('JFET Design and Application Manual', 1980), which has a small section of
>application notes at the end - unfortunately it is very sparse too: the op
>amp is shown as a 741; the JFET either 2N4302 or 2N4220; input resistor (on
>-ve in) and resistor to ground (on +ve in) are both 510 ohms; feedback
>resistor 'RF' not given (useful huh?). No equations or anything, but the
>figure caption says: "Electronic gain control utilizing the low offset
>voltage of the 741, the JFET will have linear resistance over several
>decades".
>
>I'm sure I have seen this somewhere else, but a quick skim of my FET books
>didn't uncover it - maybe I'll have another more leisurely peruse.
>
>I agree with Achim that it must be acting as some sort of subtractor, but my
>feeble attempt so far at analyzing it hasn't made much sense!
>
>Tim
>__________________________________________________________
>Tim Stinchcombe 
>
>Cheltenham, Glos, UK
>email: tim102 at tstinchcombe.freeserve.co.uk
>
>
>
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 13 22:28:42 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 13 Apr 2008 21:28:42 +0100
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804131938.m3DJctf4029601@linux7.lan>
Message-ID: <000001c89da4$faab3220$42644154@stingo>

> Does it look like this ASCIImatic:

Yep, that is as per the circuit in the Teledyne book: JFET is n-channel, is
shown with no resistor on the gate, but has a '-' (minus) on it.

Tim

> 
> 
>                                 FB ?
> 
>                        +------\/\/\/\---+
>             510R       |                |
>                        |  |\            |
>     IN *--/\/\/\/---+--+--|-\           |
>                     |     |  \          |
>                     |     |   \         |   out
>                   |-+     |    >--------+----->
>                   |       |   /
> cont *-/\/\/\/--->|-+     |  /
>                     |  +--|+/
>           ???       |  |  |/ 
>                     +--+
>                     |
>                     |
>                     /
>                     \ 510R
>                     /
>                     \
>                     /
>                     |
>                     |
>                   GND
> 
> 





From rtellason at verizon.net  Sun Apr 13 22:58:28 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Sun, 13 Apr 2008 16:58:28 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804131911.25634.Stromeko@nexgo.de>
References: <200804121318.37275.rtellason@verizon.net>
	<200804131911.25634.Stromeko@nexgo.de>
Message-ID: <200804131658.28434.rtellason@verizon.net>

On Sunday 13 April 2008 13:11, ASSI wrote:
> On Samstag 12 April 2008, Roy J. Tellason wrote:
> > It's a very simple circuit,  really.  An op amp inverting amplifier,
> > one resistor going from the non-inverting input to ground,  one input
> > resistor, and one feedback resistor.  And,  a JFET connected between
> > the two input terminals with the gate lead labeled as being the gain
> > input.
>
> What you have there is a "condensed" version of an adder/subtractor
> circuit.  When the JFET is off, you get just the normal inverting
> amplifier, when it is conducting, you mix the inverted with some
> portion of the non-inverted signal.

There wasn't any non-inverted signal,  just that resistor going to ground...

> In this particular configuration the input resistor for the non-inverting
> input is shared with the non-inverting input.  Besides saving a resistor it
> keeps the voltage across the JFET near zero, which presumably helps getting
> a control law that is independent from the input signal (you'd suffer from
> that if the JFET was in the feedback path).

I'm still unclear as to just how this would work.  What control voltage would 
you be applying to the gate of that JFET for zero output?  For maximum?  What 
sort of a characteristic would varying this control voltage have?

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From music.maker at gte.net  Sun Apr 13 23:01:27 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Sun, 13 Apr 2008 14:01:27 -0700
Subject: [sdiy] Simple VCA?
Message-ID: <200804132101.m3DL1RAs004322@linux7.lan>

tim102 at tstinchcombe.freeserve.co.uk wrote:
>> Does it look like this ASCIImatic:
>
>Yep, that is as per the circuit in the Teledyne book: JFET is n-channel, is
>shown with no resistor on the gate, but has a '-' (minus) on it.

I would expect using a negative CV.  I'd bet a MOSFET works too.

Interesting that there's no CV input resistor.

So it's like this then:
                                 FB ?
 
                        +------\/\/\/\---+
             510R       |                |
                        |  |\            |
     IN *--/\/\/\/---+--+--|-\           |
                     |     |  \          |
                     |     |   \         |   
                   |-+     |    \        |    OUT
                   |       |     >-------+----->
 - CV *----------->|-+     |    /
                     |     |   /
                     |     |  /
                     +-----|+/
                     |     |/ 
                     |
                     /
                     \ 510R
                     /
                     \
                     /
                     |
                     |
                    GND

When I imagine this without the FET, a 500K FB resistor would give a gain of 1000. 
Input impedance seems very low (510R).  My sense is that this VCA probably works better
with smaller signal voltages.  I'm wondering if JFET input opamps would work, don't see
why not.  A dual could provide a high impedance buffer/inverter for it.  Intriguing
simplicity though.

>Tim
>>[old dwg]

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From music.maker at gte.net  Sun Apr 13 23:12:39 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Sun, 13 Apr 2008 14:12:39 -0700
Subject: [sdiy] Simple VCA?
Message-ID: <200804132112.m3DLCdoJ005516@linux7.lan>

"Roy J. Tellason" <rtellason at verizon.net> wrote:
>On Sunday 13 April 2008 13:11, ASSI wrote:
>> On Samstag 12 April 2008, Roy J. Tellason wrote:
>> > It's a very simple circuit,  really.  An op amp inverting amplifier,
>> > one resistor going from the non-inverting input to ground,  one input
>> > resistor, and one feedback resistor.  And,  a JFET connected between
>> > the two input terminals with the gate lead labeled as being the gain
>> > input.
>>
>> What you have there is a "condensed" version of an adder/subtractor
>> circuit.  When the JFET is off, you get just the normal inverting
>> amplifier, when it is conducting, you mix the inverted with some
>> portion of the non-inverted signal.
>
>There wasn't any non-inverted signal,  just that resistor going to ground...
>
>> In this particular configuration the input resistor for the non-inverting
>> input is shared with the non-inverting input.  Besides saving a resistor it
>> keeps the voltage across the JFET near zero, which presumably helps getting
>> a control law that is independent from the input signal (you'd suffer from
>> that if the JFET was in the feedback path).
>
>I'm still unclear as to just how this would work.  What control voltage would 
>you be applying to the gate of that JFET for zero output?  

Zero is probably not achievable, but probably grounding the gate will give minimum VCA
output.  The JFET must be reverse biased, so a negative voltage would control it, the more
negative the gate, the higher ther resistance the JFET presents.

>For maximum?  

The max negative voltage the FET can take should cause very high resistance across D & S. 
The higher the resistance across S & D the more it's like the FET isn't there.  If the FET
resistance is millions of ohms, it effectively isn't there at all.

>What sort of a characteristic would varying this control voltage have?

I'd not expect this to be linear, but wasn't there a post that said linear control through
several decades?  Maybe the first post?


-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From veronica.merryfield at shaw.ca  Sun Apr 13 23:16:49 2008
From: veronica.merryfield at shaw.ca (Veronica Merryfield)
Date: Sun, 13 Apr 2008 14:16:49 -0700
Subject: [sdiy] Old minimoog oscillator board
In-Reply-To: <2130DC00-4BE0-4563-9C9A-594B9F30E3B8@blueyonder.co.uk>
References: <memo.831293@cix.compulink.co.uk>
	<2130DC00-4BE0-4563-9C9A-594B9F30E3B8@blueyonder.co.uk>
Message-ID: <9704DAF9-E819-4F01-920A-5E36C2EE4E78@shaw.ca>

But only a tiny amount!

I have all of season 1 and 2 and the christmas special :)

But i was terribly terribly drunk!

On 13-Apr-08, at 12:13 PM, GRAHAM ATKINS wrote:
> Thanks Jesse (Keith),
>
> It's a shame most people outside the UK won't appreciate your
> joke.........Which was nice !
>
> Graham
>
> On Apr 13, 2008, at 17:26, Keith Winstanley wrote:
>
>> today, I have mostly been matching transistors for my discrete
>> minimoog oscillator board.
>>
>> Keith
>>
>> http://home.freeuk.net/lowpass
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From aym-htnys at teaser.fr  Sun Apr 13 23:19:32 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Sun, 13 Apr 2008 23:19:32 +0200
Subject: [sdiy] Simple VCA?
In-Reply-To: <000001c89da4$faab3220$42644154@stingo>
References: <200804131938.m3DJctf4029601@linux7.lan>
	<000001c89da4$faab3220$42644154@stingo>
Message-ID: <20080413211932.GB4544@aym.net2.nerim.net>

On 2008-04-13 21:28 +0100, Tim Stinchcombe wrote:

> > Does it look like this ASCIImatic:
> >
> >                                 FB ?
> >                        +------\/\/\/\---+
> >             510R       |                |
> >                        |  |\            |
> >     IN *--/\/\/\/---+--+--|-\           |
> >                     |     |  \          |
> >                     |     |   \         |   out
> >                   |-+     |    >--------+----->
> >                   |       |   /
> > cont *-/\/\/\/--->|-+     |  /
> >                     |  +--|+/
> >           ???       |  |  |/ 
> >                     +--+
> >                     |
> >                     |
> >                     /
> >                     \ 510R
> >                     /
> >                     \
> >                     /
> >                     |
> >                     |
> >                   GND
>
> Yep, that is as per the circuit in the Teledyne book: JFET is
> n-channel, is shown with no resistor on the gate, but has a '-'
> (minus) on it.

A minus on the gate ? What does that mean ?

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From magnus at rubidium.dyndns.org  Sun Apr 13 23:33:44 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Sun, 13 Apr 2008 23:33:44 +0200 (CEST)
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804131658.28434.rtellason@verizon.net>
References: <200804121318.37275.rtellason@verizon.net>
	<200804131911.25634.Stromeko@nexgo.de>
	<200804131658.28434.rtellason@verizon.net>
Message-ID: <20080413.233344.461585788074504328.cfmd@bredband.net>

From: "Roy J. Tellason" <rtellason at verizon.net>
Subject: Re: [sdiy] Simple VCA?
Date: Sun, 13 Apr 2008 16:58:28 -0400
Message-ID: <200804131658.28434.rtellason at verizon.net>

> On Sunday 13 April 2008 13:11, ASSI wrote:
> > On Samstag 12 April 2008, Roy J. Tellason wrote:
> > > It's a very simple circuit,  really.  An op amp inverting amplifier,
> > > one resistor going from the non-inverting input to ground,  one input
> > > resistor, and one feedback resistor.  And,  a JFET connected between
> > > the two input terminals with the gate lead labeled as being the gain
> > > input.
> >
> > What you have there is a "condensed" version of an adder/subtractor
> > circuit.  When the JFET is off, you get just the normal inverting
> > amplifier, when it is conducting, you mix the inverted with some
> > portion of the non-inverted signal.
> 
> There wasn't any non-inverted signal,  just that resistor going to ground...
> 
> > In this particular configuration the input resistor for the non-inverting
> > input is shared with the non-inverting input.  Besides saving a resistor it
> > keeps the voltage across the JFET near zero, which presumably helps getting
> > a control law that is independent from the input signal (you'd suffer from
> > that if the JFET was in the feedback path).
> 
> I'm still unclear as to just how this would work.  What control voltage would 
> you be applying to the gate of that JFET for zero output?  For maximum?  What 
> sort of a characteristic would varying this control voltage have?

You guys should check out the EMS Synthi-A schematics. There is a bunch of
these in there... including the Filter Q feedback system. :)

Cheers,
Magnus


From music.maker at gte.net  Sun Apr 13 23:53:03 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Sun, 13 Apr 2008 14:53:03 -0700
Subject: [sdiy] Simple VCA?
Message-ID: <200804132153.m3DLr3fi009832@linux7.lan>

"Roy J. Tellason" <rtellason at verizon.net> wrote:
>On Sunday 13 April 2008 17:12, Scott Gravenhorst wrote:
>(Snip)
>> >I'm still unclear as to just how this would work.  What control voltage
>> > would you be applying to the gate of that JFET for zero output?
>>
>> Zero is probably not achievable, but probably grounding the gate will give
>> minimum VCA output.  The JFET must be reverse biased, so a negative voltage
>> would control it, the more negative the gate, the higher ther resistance
>> the JFET presents.
>
>I suppose I could use positive voltages with a P-channel JFET,  then...
>
>And for zero?  There seem to be a number of transistors out there spec'd 
>for "mute" applications -- I've not seen any application of those but I'd 
>guess that they would simply have the collector in the signal path and the 
>emitter tied to ground,  that'd be one way to fix it.
>
>> >For maximum?
>>
>> The max negative voltage the FET can take should cause very high resistance
>> across D & S. The higher the resistance across S & D the more it's like the
>> FET isn't there.  If the FET resistance is millions of ohms, it effectively
>> isn't there at all.
>
>Makes sense.
>
>> >What sort of a characteristic would varying this control voltage have?
>>
>> I'd not expect this to be linear, but wasn't there a post that said linear
>> control through several decades?  Maybe the first post?
>
>Mine would've been the first post,  and I was quoting what was written in that 
>book I have here.  I guess I'm gonna have to breadboard it one of these 
>days...

I wish I could get near my breadboard...  I'm one of those messy guys...  I'd love to try it
with a transistor from a 4007  (c:  They have both P and N types.  

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From lanterma at ece.gatech.edu  Sun Apr 13 23:55:42 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 13 Apr 2008 17:55:42 -0400
Subject: [sdiy] Simple VCA?
In-Reply-To: <20080413.233344.461585788074504328.cfmd@bredband.net>
References: <200804121318.37275.rtellason@verizon.net>
	<200804131911.25634.Stromeko@nexgo.de>
	<200804131658.28434.rtellason@verizon.net>
	<20080413.233344.461585788074504328.cfmd@bredband.net>
Message-ID: <68CBCE44-8479-4240-917C-2CFA55E69521@ece.gatech.edu>


On Apr 13, 2008, at 5:33 PM, Magnus Danielson wrote:

> You guys should check out the EMS Synthi-A schematics. There is a  
> bunch of
> these in there... including the Filter Q feedback system. :)

We'd love to, if we could find them...

People usual don't post schematics "out of deference to EMS..." but  
their website hasn't been updated in _10 years_, which makes it hard  
for me to take them seriously as viable synth-manufacturing entity.

(Of course, STS doesn't even have a website, which makes me take them  
even less seriously).

- Aaron


From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 13 23:57:37 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 13 Apr 2008 22:57:37 +0100
Subject: [sdiy] Simple VCA?
In-Reply-To: <20080413211932.GB4544@aym.net2.nerim.net>
Message-ID: <001101c89db1$67a814e0$42644154@stingo>

> > Yep, that is as per the circuit in the Teledyne book: JFET is 
> > n-channel, is shown with no resistor on the gate, but has a '-'
> > (minus) on it.
> 
> A minus on the gate ? What does that mean ?

I saw it as just a 'reminder' that the gate should be significantly negative
so as not to forward bias the gate-channel junction of the JFET.

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk
 






From samppa.tolvanen at gmail.com  Mon Apr 14 00:53:04 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Mon, 14 Apr 2008 01:53:04 +0300
Subject: [sdiy] Simple VCA?
In-Reply-To: <68CBCE44-8479-4240-917C-2CFA55E69521@ece.gatech.edu>
References: <200804121318.37275.rtellason@verizon.net>
	<200804131911.25634.Stromeko@nexgo.de>
	<200804131658.28434.rtellason@verizon.net>
	<20080413.233344.461585788074504328.cfmd@bredband.net>
	<68CBCE44-8479-4240-917C-2CFA55E69521@ece.gatech.edu>
Message-ID: <fa1b0bd80804131553sb064d43vfd4d03006f0f7a0@mail.gmail.com>

On 4/14/08, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
>
>  On Apr 13, 2008, at 5:33 PM, Magnus Danielson wrote:
>
>
> > You guys should check out the EMS Synthi-A schematics. There is a bunch of
> > these in there... including the Filter Q feedback system. :)
> >
>
>  We'd love to, if we could find them...
>

Oh, If Putney counts.. and yes it does ;) Yves Usson has put those up
on his http://yusynth.net/ website. Maybe just a little hard to find ~
but, it's probably better that way?

Samppa


From magnus at rubidium.dyndns.org  Mon Apr 14 01:56:48 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Mon, 14 Apr 2008 01:56:48 +0200 (CEST)
Subject: [sdiy] Simple VCA?
In-Reply-To: <68CBCE44-8479-4240-917C-2CFA55E69521@ece.gatech.edu>
References: <200804131658.28434.rtellason@verizon.net>
	<20080413.233344.461585788074504328.cfmd@bredband.net>
	<68CBCE44-8479-4240-917C-2CFA55E69521@ece.gatech.edu>
Message-ID: <20080414.015648.525984583396322058.cfmd@bredband.net>

From: Aaron Lanterman <lanterma at ece.gatech.edu>
Subject: Re: [sdiy] Simple VCA?
Date: Sun, 13 Apr 2008 17:55:42 -0400
Message-ID: <68CBCE44-8479-4240-917C-2CFA55E69521 at ece.gatech.edu>

> 
> On Apr 13, 2008, at 5:33 PM, Magnus Danielson wrote:
> 
> > You guys should check out the EMS Synthi-A schematics. There is a bunch of
> > these in there... including the Filter Q feedback system. :)
> 
> We'd love to, if we could find them...

I assumed that this page was on your radar screen, as it has been on mine for
many long years.
http://www.hinton-instruments.co.uk/ems/emsmods.html

You want to check the Output amplifiers and the Envelope generators. Those are
the "visible" 3 VCAs in that design.

> People usual don't post schematics "out of deference to EMS..." but their
> website hasn't been updated in _10 years_, which makes it hard for me to take
> them seriously as viable synth-manufacturing entity.

Well, as long as the phone number and email address is correct and their
customers find them and is happy about the service, let's cool it. To the best
of my knowledge they do provide the support and service. New machines, it looks
a bit less clear. The important stuff is there.

> (Of course, STS doesn't even have a website, which makes me take them even less seriously).

STS delivers. A friend of mine recently received a nice panel and I sure
enjoyed patching it.

Cheers,
Magnus


From pfperry at melbpc.org.au  Mon Apr 14 02:17:02 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 14 Apr 2008 10:17:02 +1000
Subject: [sdiy] Chaotic/lo-fi patching techniques
In-Reply-To: <FC7D1D9C-6B38-4EDF-9D3F-64CD9E87284F@gmail.com>
Message-ID: <004c01c89dc4$dd8179a0$8501a8c0@ice9>

Well you can always just make a PCB in the usual way.
And get it plated.

Paul perry Melbourne Australia

-----Original Message-----
On Apr 8, 2008, at 11:24 AM, Tom Bugs wrote:

Is there maybe some company out there that makes custom-designed touch  
plate things on a one-off basis? That would be interesting to find  
out. Kind of Schaeffer does for frontpanels...




From music.maker at gte.net  Mon Apr 14 04:47:27 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Sun, 13 Apr 2008 19:47:27 -0700
Subject: [sdiy] Simple VCA?
Message-ID: <200804140247.m3E2lQ05029474@linux7.lan>

"Roy J. Tellason" <rtellason at verizon.net> wrote:
>On Sunday 13 April 2008 17:53, Scott Gravenhorst wrote:
>> >> >What sort of a characteristic would varying this control voltage have?
>> >>
>> >> I'd not expect this to be linear, but wasn't there a post that said
>> >> linear control through several decades?  Maybe the first post?
>> >
>> >Mine would've been the first post,  and I was quoting what was written in
>> > that book I have here.  I guess I'm gonna have to breadboard it one of
>> > these days...
>>
>> I wish I could get near my breadboard...  I'm one of those messy guys... 
>
>I've been a little disorganized lately,  myself.  I don't even know where mine 
>are at this point in time.
>
>> I'd love to try it with a transistor from a 4007  (c:  They have both P and
>> N types.
>
>Good idea!  Except that those parts are kind of limited in terms of what 
>voltages they can deal with,  by comparison with discrete JFETs.  OTOH,  I 
>bet I could lay hands on one of those a whole lot easier than I could find a 
>JFET...

And you get 3 P-MOSFETs in each package.

As far as the voltages go, 4007 can handle up to 15 volts.  The voltage accross D and S
would be small anyway, and the gate needs a range from the + rail to ground, so I think it
could work.

I think both JFETs and MOSFETs are worth a try.  What's so nice about 4007 is that you have
P and N right there.  If you want/need it to work inversely proportional, use the N, if you
want/need it proportional, then use the P.

>For that matter,  if it's pssible to bias say an inverter to linear operation 
>I wonder why something of the sort couldn't be done with a transmission gate?

The inverters you refer to are unbuffered, as in 4069UB (same can be done with 4007).  They
can work as linear amps because each inverter is just 2 transistors with the gates connected
together.  The 4066 buffers the control line so it can't apply anything but rail voltages to
the gates of the pass transistors.  The 4016 is quite a bit simpler, but still allows access
to only one of the pass transistor's gates.
 
>Use a pair of those transistors.  One of those pins at least can be sitting 
>at virtual ground,  anyhow...
>
>-- 
>Member of the toughest, meanest, deadliest, most unrelenting -- and
>ablest -- form of life in this section of space,  a critter that can
>be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>-
>Information is more dangerous than cannon to a society ruled by lies. --James 
>M Dakin
>

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From ijfritz at comcast.net  Mon Apr 14 05:31:44 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Sun, 13 Apr 2008 21:31:44 -0600
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <200804140247.m3E2lQ05029474@linux7.lan>
References: <200804140247.m3E2lQ05029474@linux7.lan>
Message-ID: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net>

Hello --

I'm looking at the LM331 data sheet and can't figure out what the 
transistor in Fig. 4 is for.  They just say that Fig. 3 has been modified 
for high freq operation.  Any expertise or ideas?  Something to do with 
startup?

Thanks!

  Ian



From pfperry at melbpc.org.au  Mon Apr 14 06:08:48 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 14 Apr 2008 14:08:48 +1000
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net>
Message-ID: <006f01c89de5$3e52e230$8501a8c0@ice9>

My guess - and it is only a guess - is that it puts a little non-linearity
in the F/V curve, to compensate for a little gap when switching occurs.
Like the high end freq tweak seen in many synth VCOs.

Paul perry Melbourne Australia

-----Original Message-----
On Behalf Of Ian Fritz


I'm looking at the LM331 data sheet and can't figure out what the 
transistor in Fig. 4 is for.  They just say that Fig. 3 has been modified 
for high freq operation.  Any expertise or ideas?  Something to do with 
startup?




From m.bareille at free.fr  Mon Apr 14 11:06:05 2008
From: m.bareille at free.fr (m.bareille at free.fr)
Date: Mon, 14 Apr 2008 11:06:05 +0200
Subject: [sdiy] Quantix-8 - news and site update...
Message-ID: <1208163965.48031e7da8523@imp.free.fr>

Hello,

Thanks for all the replies and very positives feedback about the Quantix-8 ! I
have been a little bit flooded and it took me a while to answer to everybody :)

Here are some projects news :

1)The Quantix-8 can now read 8 bits samples an easy way...It have  6 different
memory sample maps. There are infos of 'how it work', two'hardcore' demos sound
clips with the wavetable file to make them ... +/- at the end of the web page

2) the ZERO plug is now a Logic input to reset PIC internal counters. The zero
crossing detector output is still available on the pcb and should be wired to
the panel anyway ...

3)The Final pcb will be v1.1 . It include a couple of extra resitors, and a
little connector for the input bias switch. Silkprint modified to keep parts
number  still visible after assembly. I am still waiting to collect pcb fabs
infos ... Here i am not really flooded ;)

4)I have updated/completed the web page with many picture and infos. I hope
explanations are quite clear...

5)As a friend told me quite recently: 'it is a true Pandora box!' To add cool
features to this board will never end !!!  But be aware that for the moment i am
trying to close the box again ;) Please feel free to check my magic box at
http://m.bareille.free.fr/modular1/quantix8/quantix8.htm

Thanks again to all project supporters :)

Cheers,

Marc B.






From ijfritz at comcast.net  Mon Apr 14 14:49:10 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Mon, 14 Apr 2008 06:49:10 -0600
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <006f01c89de5$3e52e230$8501a8c0@ice9>
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net>
	<006f01c89de5$3e52e230$8501a8c0@ice9>
Message-ID: <6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net>

At 10:08 PM 4/13/2008, Paul Perry wrote:
>My guess - and it is only a guess - is that it puts a little non-linearity
>in the F/V curve, to compensate for a little gap when switching occurs.
>Like the high end freq tweak seen in many synth VCOs.

The reason I'm puzzled is that pin 2 is a dc bias point, so I'm not seeing 
a frequency dependence there.

I made a homebrew charge balance VCO and compensated a bit of HF droop with 
a small resistor in series with the integrating cap.  This kind of VCO is 
amazing.  Too bad the quasi-saw output isn't nicer.

   Ian 



From lanterma at ece.gatech.edu  Mon Apr 14 19:56:41 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 13:56:41 -0400
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
Message-ID: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>

Ship date April 4, 2008. Product delivered 9:03 PM.

Name: Zachary Xavier Lanterman
Weight: 6 pounds and 14 ounces
Primary dimension: 20 inches
Features: Capable of making a wide variety high-pitched, frequency- 
modulated sounds.

http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008

This is a unique design, and not for sale. After building our first  
product, my design and construction partner, my wife (who did most of  
the construction), has absolutely no plans whatsoever to go into full- 
scale production.

- Aaron


From sounddoctorin at imt.net  Mon Apr 14 21:16:33 2008
From: sounddoctorin at imt.net (Bob Weigel)
Date: Mon, 14 Apr 2008 13:16:33 -0600
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
In-Reply-To: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
Message-ID: <4803AD91.4090603@imt.net>

Congratulations! 

I believe what you have here is a machine which can actually process 
carefully selected organic materials in order to produce an increasingly 
wide variety of synthesis processes!  (ISA.... internally spawning 
architecture!  It actually creates it's OWN UPGRADES!  You never have to 
install them!) Is it equipped with a large number of pressure modulation 
sensors?  While I understand your 'baby' is probably completely unique 
in many ways, I think I may have witnessed models that have some similar 
features.  :-)

Aaron Lanterman wrote:

> Ship date April 4, 2008. Product delivered 9:03 PM.
>
> Name: Zachary Xavier Lanterman
> Weight: 6 pounds and 14 ounces
> Primary dimension: 20 inches
> Features: Capable of making a wide variety high-pitched, frequency- 
> modulated sounds.
>
> http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008 
>
>
> This is a unique design, and not for sale. After building our first  
> product, my design and construction partner, my wife (who did most of  
> the construction), has absolutely no plans whatsoever to go into full- 
> scale production.
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>


From mirwin at marketbridge.ca  Mon Apr 14 21:57:45 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Mon, 14 Apr 2008 15:57:45 -0400
Subject: [sdiy] Any LM331 experts around?
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net><006f01c89de5$3e52e230$8501a8c0@ice9>
	<6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net>
Message-ID: <000701c89e69$cfa96900$dedb47d1@ca>

Maybe contact Bob Pease at Nat Semi - he designed it.

VCO in Roland Jupiter-4 ( JP-4 ) also a charge-balancing design with uA726
in front with digital range and waveform selection.
Mike


----- Original Message -----
From: Ian Fritz <ijfritz at comcast.net>
To: Paul Perry <pfperry at melbpc.org.au>; <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 14, 2008 8:49 AM
Subject: RE: [sdiy] Any LM331 experts around?


> At 10:08 PM 4/13/2008, Paul Perry wrote:
> >My guess - and it is only a guess - is that it puts a little
non-linearity
> >in the F/V curve, to compensate for a little gap when switching occurs.
> >Like the high end freq tweak seen in many synth VCOs.
>
> The reason I'm puzzled is that pin 2 is a dc bias point, so I'm not seeing
> a frequency dependence there.
>
> I made a homebrew charge balance VCO and compensated a bit of HF droop
with
> a small resistor in series with the integrating cap.  This kind of VCO is
> amazing.  Too bad the quasi-saw output isn't nicer.
>
>    Ian
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Mon Apr 14 22:08:35 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 16:08:35 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
Message-ID: <AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>

On Apr 14, 2008, at 2:48 PM, Tim Parkhurst wrote:

> Tim (of course, a CLONE would be the ultimate DIY project...) Servo

I know some manufacturers do build several prototypes at once. It's  
not clear that the customer actually ordered more than one, but  
sometimes some extras get thrown in. I spoke to one guy at the  
hospital whose wife had just had triplets - he had three little notes  
on his wrist. I also spoke with a woman who as having triplets who had  
to be in the hospital the entire last month of her pregnancy due to  
complications.

Being a new dad, I could easily do nothing but talk about diapers and  
breastfeeding and things like that all day. But since this is SDIY and  
not BDIY (baby do-it-your-self), I now force myself back to synths...

My students are starting work on their final projects. One of them is  
Van Halen obsessed, so I suggest he build the VCO from the Oberheim  
SEM. (Yes, I know Jump wasn't done on and SEM, and yes I know that  
custom ICs were used in the synth used on Jump, and yes I know that  
any sawtooth will do, and yes I know more modern VCO designs will be  
"better" - but any "hook" I can find to get the students interested  
works for me). One of the parameters of the project is that the  
students can't build something "as is" - they must make some kind of  
twist on the design. Depending on the particular project, can be as  
simple as updating the components (which sometimes turns out to be  
trickier than you'd thing!)

So I pointed him here: http://www.crowncity.net/ratcave/Electro/Oberheim/SEM-1A.pdf 
  and told him to look
at VCO1.  I suggested updating the op amps with TL08xs or TL07xs, and  
using a CA3046 (which I happen to have a lot of on hand) instead of  
the CA3086.

Then I started looking for discrete transistors to update. Q2 and Q3  
are just a straight dual FET voltage buffer, and Q4 is a PNP emitter  
follower. I recognize the dual FET voltage buffer as a good thing  
because of its high input impedance.

a) Why add the the BJT emitter follower buffer? Is it because it can  
provide more current that the dual FET voltage buffer?

b) Could we safely replace the FET buffer and BJT buffer with say a  
TL08x/TL07x buffer? If so... when would it NOT be safe to make such  
replacements? When would one really want to stick with the dual FET?  
(I do recognize that the dual FET would be faster than an op amp).

c) This is related to part (b)... the emitter follower (Q4) will have  
an output that will ride one "diode drop" above the input. If we  
replaced the buffers with op amps, would we need to tweak any of the  
rest of the circuit to compensate for the fact that the 0.7-ish V  
difference is no longer there?

d) This is related to (c) - any insights on what D1, Q5, Q6, and Q7  
are doing? Clearly they must be doing some combination of acting as a  
comparator and charging up the 1000 pf integrating cap when the  
comparator trips.

e) Q9 and Q8 look like output and input buffers, respective. Are they  
ripe for replacement with op-amps?

f) Question for the old-timers - why so many discrete transistors? Is  
it that the op amps were expensive at the time? Op amps seem so much  
easier to use (although they have their dangers).

My guess is that Q7 is acting as some sort of switch, shorting the top  
of the cap to +15 volts (hence "charging up") the cap when the  
sawtooth needs reset. The rest of the time Q7 is switched "off" and  
the expo converter drains the charge from the cap. Does that sound  
like a good guess?

If so, I'm still puzzled on Q5 and Q6... but I must admit, I suck at  
discrete transistors. I just recognize patterns I've seen in The Art  
of Electronics. ;)

Maybe R29 is providing some "positive feedback" to make the comparator  
trip faster?

I'm asking these questions since (a) it will provide debugging  
insights when we get to that stage and (b) I want to make sure I don't  
lead my student down the wrong path.

- Aaron, really a DSP/radar/image processing guy who got into analog  
synths because they looked like fun


From lanterma at ece.gatech.edu  Mon Apr 14 22:09:29 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 16:09:29 -0400
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <000701c89e69$cfa96900$dedb47d1@ca>
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net><006f01c89de5$3e52e230$8501a8c0@ice9>
	<6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net>
	<000701c89e69$cfa96900$dedb47d1@ca>
Message-ID: <7FDD4E14-1A50-4502-AA89-5BEA23D4C413@ece.gatech.edu>


On Apr 14, 2008, at 3:57 PM, Mike I wrote:

> Maybe contact Bob Pease at Nat Semi - he designed it.
>
> VCO in Roland Jupiter-4 ( JP-4 ) also a charge-balancing design with  
> uA726
> in front with digital range and waveform selection.

Is this related to the "charge pump" in the Rhodes Chroma VCO? (I was  
thinking that might also make a good student project)

- Aaron


From tim102 at tstinchcombe.freeserve.co.uk  Mon Apr 14 22:13:35 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Mon, 14 Apr 2008 21:13:35 +0100
Subject: [sdiy] Simple VCA?
In-Reply-To: <200804132101.m3DL1RAs004322@linux7.lan>
Message-ID: <000401c89e6c$092363f0$bd7b4f51@stingo>

With the circuit as drawn by Scott (below) my (nearly) considered opinion is
that it is just an inverting op amp set-up, the JFET might well as not be
there.

I got an analysis worked out (not double-checked though), and when I made
all the '1/gain' terms go to zero for an op amp gain of 100,000 (say) it is
just an inverting set-up. I then ran a quick simulation with 1V input, a
2N3819 and a 741, with the feedback resistor at 2k4, and I got -5x gain, as
I swept the gate voltage from -3V up to 0.

There is a little 'kink' at -2V gate, presumably the threshold voltage where
the JFET starts to conduct, and the gain does ramp, but the change in the
o/p voltage (at 0V gate) is around 400uV (i.e. peanuts). Then when I read
Scott's comments about small input voltages, I stepped the input from 1uV up
to 1V, and with 100uV in, it _almost_ looks like it is doing something
interesting, but when I realised I was dealing with input currents in the
region of 200nA, and that changing the sign of the input voltage just
*shifted* the whole output voltage curve up (i.e. rather than flipping it!),
I decided I was on a hiding to nothing (the input bias currents of the OA
probably having some effect...?), and wasn't going to spend any more time on
it!

I predict if anyone actually breadboards it, you'll get pretty much zippo
'VCA' effect out of it (but I'll keep my eye on the thread if anyone can
show me that I'm wrong!). I suspect the reason it isn't to be found anywhere
else is that other people soon realised this, and didn't copy it. Another
similar version I *did* see was to 'split' the input resistor in two, and
have the JFET coming off the confluence of these two. Then it should really
act more like a variable subtractor (and I'll add 'I think'...as I don't
know that I'm that bothered to check!).

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk


> So it's like this then:
>                                  FB ?
>  
>                         +------\/\/\/\---+
>              510R       |                |
>                         |  |\            |
>      IN *--/\/\/\/---+--+--|-\           |
>                      |     |  \          |
>                      |     |   \         |   
>                    |-+     |    \        |    OUT
>                    |       |     >-------+----->
>  - CV *----------->|-+     |    /
>                      |     |   /
>                      |     |  /
>                      +-----|+/
>                      |     |/ 
>                      |
>                      /
>                      \ 510R
>                      /
>                      \
>                      /
>                      |
>                      |
>                     GND
> 
> When I imagine this without the FET, a 500K FB resistor would 
> give a gain of 1000. 
> Input impedance seems very low (510R).  My sense is that this 
> VCA probably works better with smaller signal voltages.  I'm 
> wondering if JFET input opamps would work, don't see why not. 
>  A dual could provide a high impedance buffer/inverter for 
> it.  Intriguing simplicity though.






From jhaible at debitel.net  Mon Apr 14 22:17:01 2008
From: jhaible at debitel.net (JH.)
Date: Mon, 14 Apr 2008 22:17:01 +0200
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
Message-ID: <003a01c89e70$9df3de70$0400a8c0@jhsilent>

Congratulations!

JH.


----- Original Message ----- 
From: "Aaron Lanterman" <lanterma at ece.gatech.edu>
To: "SDIY" <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 14, 2008 7:56 PM
Subject: [sdiy] Announcing the release of my newest synth: The ZXL


Ship date April 4, 2008. Product delivered 9:03 PM.

Name: Zachary Xavier Lanterman
Weight: 6 pounds and 14 ounces
Primary dimension: 20 inches
Features: Capable of making a wide variety high-pitched, frequency-
modulated sounds.

http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008

This is a unique design, and not for sale. After building our first
product, my design and construction partner, my wife (who did most of
the construction), has absolutely no plans whatsoever to go into full-
scale production.

- Aaron
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From xyzzy at sysabend.org  Mon Apr 14 22:32:22 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Mon, 14 Apr 2008 13:32:22 -0700
Subject: [sdiy] 1v/Oct CV 'standards'?
In-Reply-To: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>
References: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>
Message-ID: <20080414203222.GO87399@moo.sysabend.org>

On Mon, Apr 14, 2008 at 08:35:16PM +0000, Justin Owen wrote:
> For a VCO that  uses 1 volt per octave tuning is there a 'standard' (i.e. most widely used) for what note (or how many Hertz) 1 volt would/should be?
> 

I asked this question a while back and got several answers but no concensus
it seems.

Midi note 0 theoretically should be 8.17hz.  I found with my VCOs at the
time that I got a usable 8 octave range so tuning them for 0volts = 8.17hz
didn't give me much overall range.  I finally decided for those VCOs to tune
0volt = 32.70hz.  When I finally assemble the MOTM boards I got, I will
definatly start at 0v=8.17hz=C0 for those.

Most synths 0volts=C, a notable exception is Moog where 0volts=F.

Here's a quick reference:
http://www.borg.com/~jglatt/tutr/notefreq.htm

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From juzowen at googlemail.com  Mon Apr 14 22:35:16 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Mon, 14 Apr 2008 20:35:16 +0000
Subject: [sdiy] 1v/Oct CV 'standards'?
Message-ID: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>

Hey all,

For a VCO that  uses 1 volt per octave tuning is there a 'standard' (i.e. most widely used) for what note (or how many Hertz) 1 volt would/should be?

I thought initially it would be 1 octave above 0Hz (genius!) - but apparently the SH101 (and others) had 1 volt sitting at C3? - and now I'm told that some synths might have based it on A (as in A3/440Hz) - not C.

...or is it generally just the case that any given VCO will have a certain number of useable/stable octaves and then you calibrate/tune it based on a) the musical range you're most likely to be using and/or b) whatever your CV controller is capable of outputting?

Reason I'm asking is that I've got an oscillator here that I'd like to try and get logarithmic voltage control over so I can use my Philip Rees Little MCV to control it via MIDI.

Obviously I can can transpose and switch keyboard ranges in my sequencing program and the MCV will let me fine tune over approx 4 octaves, which should be fine no matter what range I go for - guess I'm just curious about what people here are using.

Cheers - J




From somnium7 at gmail.com  Mon Apr 14 22:49:13 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Mon, 14 Apr 2008 16:49:13 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
Message-ID: <916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>

Aaron,

This VCO isn't an easy project for a student IMO. I have worked on
making a clone of it and have had many problems. Some of which I still
can't solve.

Q2 and Q3 are 2N4302 devices which have some squirrly behaivior traits
and really bad matching between devices. I may be wrong about this but
I think Q4 is simply there to invert the wave.

Replacing this buffer stage with an opamp might be tricky because the
comparator stage after D1 is very sensitive to the pp voltage level
applied to it. This is also the reason for the 18.5V supply voltage.
However, the trigger threshold for the comparator can be changed with
R24 and R28.
It's probably much less work to just try a comparator chip after an
opamp buffer. But then you would be working with something more like
the ASM1 VCO than the SEM.

Q5 and Q6 are the comparator. R29 I'm not sure about. I originally
thought it was for resetting the comparator but I'm probably wrong
there.

Q7 works the way you described it.

I actually do not recommend upgrading any of the opamps. Nothing else
I've tried works properly for A4. Something particular about the 301
seems to be at play here. Also, I found oddly enough that modern 741s
do not work so well for A2 and A3. I tried some NOS 70s era 741s and
got much better performance in my clone circuit.

I'm still stuck on how to get more than 2 octaves of range out of my
clone. I got frustrated and shelved the project after not being able
to solve the problem.
I really should go back and rebuild it from scratch. I think I still
have two of the PCBs I made for it I can work with.

Maybe if I start over again after all this time the problem will be
more apparent...

Good luck if you do try it.

Mike





On Mon, Apr 14, 2008 at 4:08 PM, Aaron Lanterman
<lanterma at ece.gatech.edu> wrote:
> On Apr 14, 2008, at 2:48 PM, Tim Parkhurst wrote:
>
>
> > Tim (of course, a CLONE would be the ultimate DIY project...) Servo
> >
>
>  I know some manufacturers do build several prototypes at once. It's not
> clear that the customer actually ordered more than one, but sometimes some
> extras get thrown in. I spoke to one guy at the hospital whose wife had just
> had triplets - he had three little notes on his wrist. I also spoke with a
> woman who as having triplets who had to be in the hospital the entire last
> month of her pregnancy due to complications.
>
>  Being a new dad, I could easily do nothing but talk about diapers and
> breastfeeding and things like that all day. But since this is SDIY and not
> BDIY (baby do-it-your-self), I now force myself back to synths...
>
>  My students are starting work on their final projects. One of them is Van
> Halen obsessed, so I suggest he build the VCO from the Oberheim SEM. (Yes, I
> know Jump wasn't done on and SEM, and yes I know that custom ICs were used
> in the synth used on Jump, and yes I know that any sawtooth will do, and yes
> I know more modern VCO designs will be "better" - but any "hook" I can find
> to get the students interested works for me). One of the parameters of the
> project is that the students can't build something "as is" - they must make
> some kind of twist on the design. Depending on the particular project, can
> be as simple as updating the components (which sometimes turns out to be
> trickier than you'd thing!)
>
>  So I pointed him here:
> http://www.crowncity.net/ratcave/Electro/Oberheim/SEM-1A.pdf and told him to
> look
>  at VCO1.  I suggested updating the op amps with TL08xs or TL07xs, and using
> a CA3046 (which I happen to have a lot of on hand) instead of the CA3086.
>
>  Then I started looking for discrete transistors to update. Q2 and Q3 are
> just a straight dual FET voltage buffer, and Q4 is a PNP emitter follower. I
> recognize the dual FET voltage buffer as a good thing because of its high
> input impedance.
>
>  a) Why add the the BJT emitter follower buffer? Is it because it can
> provide more current that the dual FET voltage buffer?
>
>  b) Could we safely replace the FET buffer and BJT buffer with say a
> TL08x/TL07x buffer? If so... when would it NOT be safe to make such
> replacements? When would one really want to stick with the dual FET? (I do
> recognize that the dual FET would be faster than an op amp).
>
>  c) This is related to part (b)... the emitter follower (Q4) will have an
> output that will ride one "diode drop" above the input. If we replaced the
> buffers with op amps, would we need to tweak any of the rest of the circuit
> to compensate for the fact that the 0.7-ish V difference is no longer there?
>
>  d) This is related to (c) - any insights on what D1, Q5, Q6, and Q7 are
> doing? Clearly they must be doing some combination of acting as a comparator
> and charging up the 1000 pf integrating cap when the comparator trips.
>
>  e) Q9 and Q8 look like output and input buffers, respective. Are they ripe
> for replacement with op-amps?
>
>  f) Question for the old-timers - why so many discrete transistors? Is it
> that the op amps were expensive at the time? Op amps seem so much easier to
> use (although they have their dangers).
>
>  My guess is that Q7 is acting as some sort of switch, shorting the top of
> the cap to +15 volts (hence "charging up") the cap when the sawtooth needs
> reset. The rest of the time Q7 is switched "off" and the expo converter
> drains the charge from the cap. Does that sound like a good guess?
>
>  If so, I'm still puzzled on Q5 and Q6... but I must admit, I suck at
> discrete transistors. I just recognize patterns I've seen in The Art of
> Electronics. ;)
>
>  Maybe R29 is providing some "positive feedback" to make the comparator trip
> faster?
>
>  I'm asking these questions since (a) it will provide debugging insights
> when we get to that stage and (b) I want to make sure I don't lead my
> student down the wrong path.
>
>  - Aaron, really a DSP/radar/image processing guy who got into analog synths
> because they looked like fun
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From seb at burnit.co.uk  Mon Apr 14 23:00:09 2008
From: seb at burnit.co.uk (Seb Francis)
Date: Mon, 14 Apr 2008 22:00:09 +0100
Subject: [sdiy] 1v/Oct CV 'standards'?
In-Reply-To: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>
References: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>
Message-ID: <4803C5D9.30705@burnit.co.uk>

Personally I like to use 0V for C3 which is -5V to +5.583V for the full 
MIDI note range.  Allowing for pitch bends, etc. this still keeps 
everything comfortably away from the supply rails even for relatively 
low voltage systems like +/-9V.

Seb


Justin Owen wrote:
> Hey all,
>
> For a VCO that  uses 1 volt per octave tuning is there a 'standard' (i.e. most widely used) for what note (or how many Hertz) 1 volt would/should be?
>
> I thought initially it would be 1 octave above 0Hz (genius!) - but apparently the SH101 (and others) had 1 volt sitting at C3? - and now I'm told that some synths might have based it on A (as in A3/440Hz) - not C.
>
> ..or is it generally just the case that any given VCO will have a certain number of useable/stable octaves and then you calibrate/tune it based on a) the musical range you're most likely to be using and/or b) whatever your CV controller is capable of outputting?
>
> Reason I'm asking is that I've got an oscillator here that I'd like to try and get logarithmic voltage control over so I can use my Philip Rees Little MCV to control it via MIDI.
>
> Obviously I can can transpose and switch keyboard ranges in my sequencing program and the MCV will let me fine tune over approx 4 octaves, which should be fine no matter what range I go for - guess I'm just curious about what people here are using.
>
> Cheers - J
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>   




From lanterma at ece.gatech.edu  Mon Apr 14 23:07:22 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 17:07:22 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
Message-ID: <343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>


On Apr 14, 2008, at 4:49 PM, mike ruberto wrote:

> This VCO isn't an easy project for a student IMO. I have worked on  
> making a clone of it and have had many problems. Some of which I  
> still can't solve.

[Many dangers snipped]

Wow... sounds like it would be better to stay away from it. Going  
along the pseudo-Van Halen interest theme, I think I'll steer him  
towards the Oberheim VCF, adding voltage controlled resonance to it (I  
know that's been done a million times, but it's still a good exercise,  
and it's a circuit I understand much much better).

- Aaron


From magnus at rubidium.dyndns.org  Mon Apr 14 23:22:33 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Mon, 14 Apr 2008 23:22:33 +0200 (CEST)
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>
References: <AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>
Message-ID: <20080414.232233.13716042268251026.cfmd@bredband.net>

From: Aaron Lanterman <lanterma at ece.gatech.edu>
Subject: Re: [sdiy] On cloning, and the Oberheim VCO
Date: Mon, 14 Apr 2008 17:07:22 -0400
Message-ID: <343B4BF1-F8DE-4015-B3A8-06AD2C77E10E at ece.gatech.edu>

> 
> On Apr 14, 2008, at 4:49 PM, mike ruberto wrote:
> 
> > This VCO isn't an easy project for a student IMO. I have worked on making a clone of it and have had many problems. Some of which I still can't solve.
> 
> [Many dangers snipped]
> 
> Wow... sounds like it would be better to stay away from it. Going along the pseudo-Van Halen interest theme, I think I'll steer him towards the Oberheim VCF, adding voltage controlled resonance to it (I know that's been done a million times, but it's still a good exercise, and it's a circuit I understand much much better).

I'll think I'll repair my SEM clone (aka ASM-1) soon. :)

Cheers,
Magnus


From gene at ixiacom.com  Mon Apr 14 23:36:13 2008
From: gene at ixiacom.com (Gene Stopp)
Date: Mon, 14 Apr 2008 14:36:13 -0700
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
Message-ID: <0A2F39512D881F4690CF73625E4161F5014AF9@IXCA-EXCHANGE.ixiacom.com>

That's what I did when I made my own SEM-type PCB, used the ASM-1 VCO's. har har

When I did the ASM-1 I copied the basic SEM format since it exemplified the classic analog synthesizer voice. However I was not interested in cloning, I was interested in creating the simplest circuits with the highest performance. Starting backwards, the VCA's were easy - the Electronotes Walter Jung diode drive to the CA3080 pin 5 was a shoe-in. For the VCF a multimode had the most flexibility and was also an easy one from Electronotes (with the Q clipper as a tribute to the SEM). The EG's I considered to be a non-audio contour and therefore independent of design, so I just made something up with an analog switch (although in retrospect I should have used a 555 for the logic to make it even simpler). But the VCO I wanted to get perfect. I breadboarded a bunch of VCO's and the big winner was Terry Michael's CA3130/FET/LM311 core, which I altered slightly with the CA3140 since those were easier to get.

Sorry Aaron this doesn't really help your student, I like the VCF modded with VCQ idea however.

And congratulations on the new arrival! We've taken delivery three times and it's really a great long-term investment. We had to stop taking delivery finally since they really do take up a lot of room and time. The 9-month lead time is pretty long but filling out the order form is great fun. What I did was block the ink flow im my pen so we can still fill out the order form over and over without committing to further deliveries.

- Gene


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of mike ruberto
Sent: Monday, April 14, 2008 1:49 PM
To: Aaron Lanterman; synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] On cloning, and the Oberheim VCO


Aaron,

This VCO isn't an easy project for a student IMO. I have worked on
making a clone of it and have had many problems. Some of which I still
can't solve.

Q2 and Q3 are 2N4302 devices which have some squirrly behaivior traits
and really bad matching between devices. I may be wrong about this but
I think Q4 is simply there to invert the wave.

Replacing this buffer stage with an opamp might be tricky because the
comparator stage after D1 is very sensitive to the pp voltage level
applied to it. This is also the reason for the 18.5V supply voltage.
However, the trigger threshold for the comparator can be changed with
R24 and R28.
It's probably much less work to just try a comparator chip after an
opamp buffer. But then you would be working with something more like
the ASM1 VCO than the SEM.

Q5 and Q6 are the comparator. R29 I'm not sure about. I originally
thought it was for resetting the comparator but I'm probably wrong
there.

Q7 works the way you described it.

I actually do not recommend upgrading any of the opamps. Nothing else
I've tried works properly for A4. Something particular about the 301
seems to be at play here. Also, I found oddly enough that modern 741s
do not work so well for A2 and A3. I tried some NOS 70s era 741s and
got much better performance in my clone circuit.

I'm still stuck on how to get more than 2 octaves of range out of my
clone. I got frustrated and shelved the project after not being able
to solve the problem.
I really should go back and rebuild it from scratch. I think I still
have two of the PCBs I made for it I can work with.

Maybe if I start over again after all this time the problem will be
more apparent...

Good luck if you do try it.

Mike





On Mon, Apr 14, 2008 at 4:08 PM, Aaron Lanterman
<lanterma at ece.gatech.edu> wrote:
> On Apr 14, 2008, at 2:48 PM, Tim Parkhurst wrote:
>
>
> > Tim (of course, a CLONE would be the ultimate DIY project...) Servo
> >
>
>  I know some manufacturers do build several prototypes at once. It's not
> clear that the customer actually ordered more than one, but sometimes some
> extras get thrown in. I spoke to one guy at the hospital whose wife had just
> had triplets - he had three little notes on his wrist. I also spoke with a
> woman who as having triplets who had to be in the hospital the entire last
> month of her pregnancy due to complications.
>
>  Being a new dad, I could easily do nothing but talk about diapers and
> breastfeeding and things like that all day. But since this is SDIY and not
> BDIY (baby do-it-your-self), I now force myself back to synths...
>
>  My students are starting work on their final projects. One of them is Van
> Halen obsessed, so I suggest he build the VCO from the Oberheim SEM. (Yes, I
> know Jump wasn't done on and SEM, and yes I know that custom ICs were used
> in the synth used on Jump, and yes I know that any sawtooth will do, and yes
> I know more modern VCO designs will be "better" - but any "hook" I can find
> to get the students interested works for me). One of the parameters of the
> project is that the students can't build something "as is" - they must make
> some kind of twist on the design. Depending on the particular project, can
> be as simple as updating the components (which sometimes turns out to be
> trickier than you'd thing!)
>
>  So I pointed him here:
> http://www.crowncity.net/ratcave/Electro/Oberheim/SEM-1A.pdf and told him to
> look
>  at VCO1.  I suggested updating the op amps with TL08xs or TL07xs, and using
> a CA3046 (which I happen to have a lot of on hand) instead of the CA3086.
>
>  Then I started looking for discrete transistors to update. Q2 and Q3 are
> just a straight dual FET voltage buffer, and Q4 is a PNP emitter follower. I
> recognize the dual FET voltage buffer as a good thing because of its high
> input impedance.
>
>  a) Why add the the BJT emitter follower buffer? Is it because it can
> provide more current that the dual FET voltage buffer?
>
>  b) Could we safely replace the FET buffer and BJT buffer with say a
> TL08x/TL07x buffer? If so... when would it NOT be safe to make such
> replacements? When would one really want to stick with the dual FET? (I do
> recognize that the dual FET would be faster than an op amp).
>
>  c) This is related to part (b)... the emitter follower (Q4) will have an
> output that will ride one "diode drop" above the input. If we replaced the
> buffers with op amps, would we need to tweak any of the rest of the circuit
> to compensate for the fact that the 0.7-ish V difference is no longer there?
>
>  d) This is related to (c) - any insights on what D1, Q5, Q6, and Q7 are
> doing? Clearly they must be doing some combination of acting as a comparator
> and charging up the 1000 pf integrating cap when the comparator trips.
>
>  e) Q9 and Q8 look like output and input buffers, respective. Are they ripe
> for replacement with op-amps?
>
>  f) Question for the old-timers - why so many discrete transistors? Is it
> that the op amps were expensive at the time? Op amps seem so much easier to
> use (although they have their dangers).
>
>  My guess is that Q7 is acting as some sort of switch, shorting the top of
> the cap to +15 volts (hence "charging up") the cap when the sawtooth needs
> reset. The rest of the time Q7 is switched "off" and the expo converter
> drains the charge from the cap. Does that sound like a good guess?
>
>  If so, I'm still puzzled on Q5 and Q6... but I must admit, I suck at
> discrete transistors. I just recognize patterns I've seen in The Art of
> Electronics. ;)
>
>  Maybe R29 is providing some "positive feedback" to make the comparator trip
> faster?
>
>  I'm asking these questions since (a) it will provide debugging insights
> when we get to that stage and (b) I want to make sure I don't lead my
> student down the wrong path.
>
>  - Aaron, really a DSP/radar/image processing guy who got into analog synths
> because they looked like fun
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Mon Apr 14 23:46:57 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 17:46:57 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <0A2F39512D881F4690CF73625E4161F5014AF9@IXCA-EXCHANGE.ixiacom.com>
References: <0A2F39512D881F4690CF73625E4161F5014AF9@IXCA-EXCHANGE.ixiacom.com>
Message-ID: <DA4CA47C-FEDF-4C9E-83B6-9CA6DC44960A@ece.gatech.edu>

On Apr 14, 2008, at 5:36 PM, Gene Stopp wrote:

> And congratulations on the new arrival! We've taken delivery three  
> times and it's really a great long-term investment. We had to stop  
> taking delivery finally since they really do take up a lot of room  
> and time. The 9-month lead time is pretty long but filling out the  
> order form is great fun.

Actually that lead time sounds pretty close to what you get ordering  
from a cottage modular manufacturer. ;)

- Aaron


From mirwin at marketbridge.ca  Tue Apr 15 00:09:34 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Mon, 14 Apr 2008 18:09:34 -0400
Subject: [sdiy] Any LM331 experts around?
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net><006f01c89de5$3e52e230$8501a8c0@ice9><6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net><000701c89e69$cfa96900$dedb47d1@ca>
	<7FDD4E14-1A50-4502-AA89-5BEA23D4C413@ece.gatech.edu>
Message-ID: <001501c89e7c$39a7f120$85db47d1@ca>

Hi - the Roland JP-4 VCO is a bits + pieces charge-balancing circuit mostly
built with standard CMOS and transistors ( no RC4151 converter as in the
Chroma). JP-4 has a reputation for going out of tune easily though, maybe
out of tune but with nice linearity.

Roland used a more typical sawtooth VCO design afterward in the JP-8 (with
autotune).

BTW congrats on latest addition!
Mike



----- Original Message -----
From: Aaron Lanterman <lanterma at ece.gatech.edu>
To: SDIY <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 14, 2008 4:09 PM
Subject: Re: [sdiy] Any LM331 experts around?


>
> On Apr 14, 2008, at 3:57 PM, Mike I wrote:
>
> > Maybe contact Bob Pease at Nat Semi - he designed it.
> >
> > VCO in Roland Jupiter-4 ( JP-4 ) also a charge-balancing design with
> > uA726
> > in front with digital range and waveform selection.
>
> Is this related to the "charge pump" in the Rhodes Chroma VCO? (I was
> thinking that might also make a good student project)
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From mrmike at clickbang.com  Tue Apr 15 02:07:18 2008
From: mrmike at clickbang.com (mrmike)
Date: Mon, 14 Apr 2008 19:07:18 -0500
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <DA4CA47C-FEDF-4C9E-83B6-9CA6DC44960A@ece.gatech.edu>
References: <0A2F39512D881F4690CF73625E4161F5014AF9@IXCA-EXCHANGE.ixiacom.com>
	<DA4CA47C-FEDF-4C9E-83B6-9CA6DC44960A@ece.gatech.edu>
Message-ID: <4803F1B6.3010005@clickbang.com>

Hardly.  I've had two organic noise makers in the same amount of time 
it's taken a certain mfg to deliver a VCO.  Actually, the VCO hasn't 
been delivered yet... and at the pace organic noise makers get generated 
around here (5 in 7 years), there may be yet another before the VCO 
arrives...

Congrats Aaron, on the new noise in your home!

click (plenty of ink left in *this* pen!) mrmike


Aaron Lanterman wrote:
> On Apr 14, 2008, at 5:36 PM, Gene Stopp wrote:
>
>> And congratulations on the new arrival! We've taken delivery three 
>> times and it's really a great long-term investment. We had to stop 
>> taking delivery finally since they really do take up a lot of room 
>> and time. The 9-month lead time is pretty long but filling out the 
>> order form is great fun.
>
> Actually that lead time sounds pretty close to what you get ordering 
> from a cottage modular manufacturer. ;)
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>



From rtellason at verizon.net  Tue Apr 15 02:30:53 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Mon, 14 Apr 2008 20:30:53 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
Message-ID: <200804142030.54101.rtellason@verizon.net>

On Monday 14 April 2008 16:49, mike ruberto wrote:
> I actually do not recommend upgrading any of the opamps. Nothing else
> I've tried works properly for A4. Something particular about the 301
> seems to be at play here. Also, I found oddly enough that modern 741s
> do not work so well for A2 and A3. I tried some NOS 70s era 741s and
> got much better performance in my clone circuit.

Now that's interesting.  I wonder what they've changed in the lowly 741?  I 
have some that have been hanging around for ages,  and have been wondering 
what I might do with them.  (A null indicator for a bridge was one project 
that came to mind...)  Some of them might even be Radio Shack parts.  Think 
they might work even better?  :-)

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From mirwin at marketbridge.ca  Tue Apr 15 04:37:32 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Mon, 14 Apr 2008 22:37:32 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu><AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu><916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<200804142030.54101.rtellason@verizon.net>
Message-ID: <001701c89ea1$a8f65ba0$bbdb47d1@ca>

My 1975 Motorola book shows a variant of the 741 called the 741S.... this is
a lot faster than the normal  741, and has a S.R. of 10V/uS. Suggested for
use at the output of the 1408 DAC. Whether this was a Motorola-specific
device, or available from several mfrs at the time, I do not know. Maybe it
was used in the SEM VCO???

Some synth schematics from back then show a 741 (S), but this was used to
indicate a normal 741 that was selected for low offset or some other
parameter.
Mike



----- Original Message -----
From: Roy J. Tellason <rtellason at verizon.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 14, 2008 8:30 PM
Subject: Re: [sdiy] On cloning, and the Oberheim VCO


> On Monday 14 April 2008 16:49, mike ruberto wrote:
> > I actually do not recommend upgrading any of the opamps. Nothing else
> > I've tried works properly for A4. Something particular about the 301
> > seems to be at play here. Also, I found oddly enough that modern 741s
> > do not work so well for A2 and A3. I tried some NOS 70s era 741s and
> > got much better performance in my clone circuit.
>
> Now that's interesting.  I wonder what they've changed in the lowly 741?
I
> have some that have been hanging around for ages,  and have been wondering
> what I might do with them.  (A null indicator for a bridge was one project
> that came to mind...)  Some of them might even be Radio Shack parts.
Think
> they might work even better?  :-)
>
> --
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space, a critter that can
> be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
> -
> Information is more dangerous than cannon to a society ruled by
lies. --James
> M Dakin
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From jmahoney at gate.net  Tue Apr 15 05:28:13 2008
From: jmahoney at gate.net (John Mahoney)
Date: Mon, 14 Apr 2008 23:28:13 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>
Message-ID: <200804150327.m3F3RW7x017828@dropmix.xs4all.nl>

At 05:07 PM 4/14/2008, Aaron Lanterman wrote:

>Wow... sounds like it would be better to stay away from it. Going
>along the pseudo-Van Halen interest theme, I think I'll steer him
>towards the Oberheim VCF, adding voltage controlled resonance to it (I
>know that's been done a million times, but it's still a good exercise,
>and it's a circuit I understand much much better).

Would the OB-X VCO be any easier? They are also discrete and are more 
closely to the "Jump" synth then the SEM. (Was it an OB-X or Xa?) 
Maybe they are so close to the SEM that they are no simpler to clone.

John 


-- 
No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.13/1377 - Release Date: 4/14/2008 9:26 AM




From jays at aracnet.com  Tue Apr 15 05:39:13 2008
From: jays at aracnet.com (Jay Schwichtenberg)
Date: Mon, 14 Apr 2008 19:39:13 -0800
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
Message-ID: <GDEMKJDLKPDJFJGFBDFGCEDLDCAA.jays@aracnet.com>

Aaron,

Might look at the EFM VCO4E. Don't know if the web site is still up for EFM.
It has more or less the same expo converter but the osc and wave shaping is
different. I've built a couple of the EFM boards for these and they work.

Congrads on hitting you project milestone. At least wait until he can focus
his eyes before you give him a soldering iron. Music lessons can start at
anytime or maybe already have.

Jay S.

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Aaron Lanterman
Sent: Monday, April 14, 2008 12:09 PM
To: SDIY
Subject: [sdiy] On cloning, and the Oberheim VCO


On Apr 14, 2008, at 2:48 PM, Tim Parkhurst wrote:

> Tim (of course, a CLONE would be the ultimate DIY project...) Servo

I know some manufacturers do build several prototypes at once. It's
not clear that the customer actually ordered more than one, but
sometimes some extras get thrown in. I spoke to one guy at the
hospital whose wife had just had triplets - he had three little notes
on his wrist. I also spoke with a woman who as having triplets who had
to be in the hospital the entire last month of her pregnancy due to
complications.

Being a new dad, I could easily do nothing but talk about diapers and
breastfeeding and things like that all day. But since this is SDIY and
not BDIY (baby do-it-your-self), I now force myself back to synths...

My students are starting work on their final projects. One of them is
Van Halen obsessed, so I suggest he build the VCO from the Oberheim
SEM. (Yes, I know Jump wasn't done on and SEM, and yes I know that
custom ICs were used in the synth used on Jump, and yes I know that
any sawtooth will do, and yes I know more modern VCO designs will be
"better" - but any "hook" I can find to get the students interested
works for me). One of the parameters of the project is that the
students can't build something "as is" - they must make some kind of
twist on the design. Depending on the particular project, can be as
simple as updating the components (which sometimes turns out to be
trickier than you'd thing!)

So I pointed him here:
http://www.crowncity.net/ratcave/Electro/Oberheim/SEM-1A.pdf
  and told him to look
at VCO1.  I suggested updating the op amps with TL08xs or TL07xs, and
using a CA3046 (which I happen to have a lot of on hand) instead of
the CA3086.

Then I started looking for discrete transistors to update. Q2 and Q3
are just a straight dual FET voltage buffer, and Q4 is a PNP emitter
follower. I recognize the dual FET voltage buffer as a good thing
because of its high input impedance.

a) Why add the the BJT emitter follower buffer? Is it because it can
provide more current that the dual FET voltage buffer?

b) Could we safely replace the FET buffer and BJT buffer with say a
TL08x/TL07x buffer? If so... when would it NOT be safe to make such
replacements? When would one really want to stick with the dual FET?
(I do recognize that the dual FET would be faster than an op amp).

c) This is related to part (b)... the emitter follower (Q4) will have
an output that will ride one "diode drop" above the input. If we
replaced the buffers with op amps, would we need to tweak any of the
rest of the circuit to compensate for the fact that the 0.7-ish V
difference is no longer there?

d) This is related to (c) - any insights on what D1, Q5, Q6, and Q7
are doing? Clearly they must be doing some combination of acting as a
comparator and charging up the 1000 pf integrating cap when the
comparator trips.

e) Q9 and Q8 look like output and input buffers, respective. Are they
ripe for replacement with op-amps?

f) Question for the old-timers - why so many discrete transistors? Is
it that the op amps were expensive at the time? Op amps seem so much
easier to use (although they have their dangers).

My guess is that Q7 is acting as some sort of switch, shorting the top
of the cap to +15 volts (hence "charging up") the cap when the
sawtooth needs reset. The rest of the time Q7 is switched "off" and
the expo converter drains the charge from the cap. Does that sound
like a good guess?

If so, I'm still puzzled on Q5 and Q6... but I must admit, I suck at
discrete transistors. I just recognize patterns I've seen in The Art
of Electronics. ;)

Maybe R29 is providing some "positive feedback" to make the comparator
trip faster?

I'm asking these questions since (a) it will provide debugging
insights when we get to that stage and (b) I want to make sure I don't
lead my student down the wrong path.

- Aaron, really a DSP/radar/image processing guy who got into analog
synths because they looked like fun
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From lanterma at ece.gatech.edu  Tue Apr 15 05:43:22 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 14 Apr 2008 23:43:22 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <200804150328.m3F3SJoP021222@mail.ee.gatech.edu>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<343B4BF1-F8DE-4015-B3A8-06AD2C77E10E@ece.gatech.edu>
	<200804150328.m3F3SJoP021222@mail.ee.gatech.edu>
Message-ID: <F9A4D4EA-4AFB-496E-A433-7FC4D96C48C4@ece.gatech.edu>


On Apr 14, 2008, at 11:28 PM, John Mahoney wrote:

> At 05:07 PM 4/14/2008, Aaron Lanterman wrote:
>
>> Wow... sounds like it would be better to stay away from it. Going
>> along the pseudo-Van Halen interest theme, I think I'll steer him
>> towards the Oberheim VCF, adding voltage controlled resonance to it  
>> (I
>> know that's been done a million times, but it's still a good  
>> exercise,
>> and it's a circuit I understand much much better).
>
> Would the OB-X VCO be any easier? They are also discrete and are  
> more closely to the "Jump" synth then the SEM. (Was it an OB-X or  
> Xa?) Maybe they are so close to the SEM that they are no simpler to  
> clone.


I found the schematics to the OB-1 and OB-X here:

http://www.bluesynths.com/modules.php?name=Manuals&rop=O

I don't know about the rest of the synth circuitry, but the VCO looks  
to be very very close, if not identical, to that of the SEM (I didn't  
look at it in a whole lot of detail though.) Too close to the SEM to  
tackle at this time, at least...

- Aaron


From mverbos at earthlink.net  Tue Apr 15 06:00:17 2008
From: mverbos at earthlink.net (mark verbos)
Date: Tue, 15 Apr 2008 00:00:17 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
Message-ID: <2B73580A-BFB9-4E8E-BDE7-13978D6703C4@earthlink.net>

Aaron,

I'd suggest you look at the Kobol oscillator on my page

http://www.simple-answer.com/DIY.html

It's basically the same one that's in an SEM, but with OPamps instead  
of those transistors for that buffer. Sadly, you'll notice that it  
uses wider supply rails than +/-15, like the SEM. They also used a  
3086 for the NPNs in the core.

Incidentally, Q4 does not invert the signal. Q5 and Q6 are a  
comparator, R29 is adding positive feedback for hysteresis, Q8 and Q9  
are switching not buffering.

My guess is that they used transistors because they are small and  
cheap. It's probably a fatter, driftier sounding oscillator for it.  
RSF used SSM chips in every part of the Kobol except the oscillator,  
it's a GREAT sounding box.

Mark




On Apr 14, 2008, at 4:49 PM, mike ruberto wrote:
> Aaron,
>
> This VCO isn't an easy project for a student IMO. I have worked on
> making a clone of it and have had many problems. Some of which I still
> can't solve.
>
> Q2 and Q3 are 2N4302 devices which have some squirrly behaivior traits
> and really bad matching between devices. I may be wrong about this but
> I think Q4 is simply there to invert the wave.
>
> Replacing this buffer stage with an opamp might be tricky because the
> comparator stage after D1 is very sensitive to the pp voltage level
> applied to it. This is also the reason for the 18.5V supply voltage.
> However, the trigger threshold for the comparator can be changed with
> R24 and R28.
> It's probably much less work to just try a comparator chip after an
> opamp buffer. But then you would be working with something more like
> the ASM1 VCO than the SEM.
>
> Q5 and Q6 are the comparator. R29 I'm not sure about. I originally
> thought it was for resetting the comparator but I'm probably wrong
> there.
>
> Q7 works the way you described it.
>
> I actually do not recommend upgrading any of the opamps. Nothing else
> I've tried works properly for A4. Something particular about the 301
> seems to be at play here. Also, I found oddly enough that modern 741s
> do not work so well for A2 and A3. I tried some NOS 70s era 741s and
> got much better performance in my clone circuit.
>
> I'm still stuck on how to get more than 2 octaves of range out of my
> clone. I got frustrated and shelved the project after not being able
> to solve the problem.
> I really should go back and rebuild it from scratch. I think I still
> have two of the PCBs I made for it I can work with.
>
> Maybe if I start over again after all this time the problem will be
> more apparent...
>
> Good luck if you do try it.
>
> Mike
>
>
>
>
>
> On Mon, Apr 14, 2008 at 4:08 PM, Aaron Lanterman
> <lanterma at ece.gatech.edu> wrote:
>> On Apr 14, 2008, at 2:48 PM, Tim Parkhurst wrote:
>>
>>
>>> Tim (of course, a CLONE would be the ultimate DIY project...) Servo
>>>
>>
>>  I know some manufacturers do build several prototypes at once.  
>> It's not
>> clear that the customer actually ordered more than one, but  
>> sometimes some
>> extras get thrown in. I spoke to one guy at the hospital whose  
>> wife had just
>> had triplets - he had three little notes on his wrist. I also  
>> spoke with a
>> woman who as having triplets who had to be in the hospital the  
>> entire last
>> month of her pregnancy due to complications.
>>
>>  Being a new dad, I could easily do nothing but talk about diapers  
>> and
>> breastfeeding and things like that all day. But since this is SDIY  
>> and not
>> BDIY (baby do-it-your-self), I now force myself back to synths...
>>
>>  My students are starting work on their final projects. One of  
>> them is Van
>> Halen obsessed, so I suggest he build the VCO from the Oberheim  
>> SEM. (Yes, I
>> know Jump wasn't done on and SEM, and yes I know that custom ICs  
>> were used
>> in the synth used on Jump, and yes I know that any sawtooth will  
>> do, and yes
>> I know more modern VCO designs will be "better" - but any "hook" I  
>> can find
>> to get the students interested works for me). One of the  
>> parameters of the
>> project is that the students can't build something "as is" - they  
>> must make
>> some kind of twist on the design. Depending on the particular  
>> project, can
>> be as simple as updating the components (which sometimes turns out  
>> to be
>> trickier than you'd thing!)
>>
>>  So I pointed him here:
>> http://www.crowncity.net/ratcave/Electro/Oberheim/SEM-1A.pdf and  
>> told him to
>> look
>>  at VCO1.  I suggested updating the op amps with TL08xs or TL07xs,  
>> and using
>> a CA3046 (which I happen to have a lot of on hand) instead of the  
>> CA3086.
>>
>>  Then I started looking for discrete transistors to update. Q2 and  
>> Q3 are
>> just a straight dual FET voltage buffer, and Q4 is a PNP emitter  
>> follower. I
>> recognize the dual FET voltage buffer as a good thing because of  
>> its high
>> input impedance.
>>
>>  a) Why add the the BJT emitter follower buffer? Is it because it can
>> provide more current that the dual FET voltage buffer?
>>
>>  b) Could we safely replace the FET buffer and BJT buffer with say a
>> TL08x/TL07x buffer? If so... when would it NOT be safe to make such
>> replacements? When would one really want to stick with the dual  
>> FET? (I do
>> recognize that the dual FET would be faster than an op amp).
>>
>>  c) This is related to part (b)... the emitter follower (Q4) will  
>> have an
>> output that will ride one "diode drop" above the input. If we  
>> replaced the
>> buffers with op amps, would we need to tweak any of the rest of  
>> the circuit
>> to compensate for the fact that the 0.7-ish V difference is no  
>> longer there?
>>
>>  d) This is related to (c) - any insights on what D1, Q5, Q6, and  
>> Q7 are
>> doing? Clearly they must be doing some combination of acting as a  
>> comparator
>> and charging up the 1000 pf integrating cap when the comparator  
>> trips.
>>
>>  e) Q9 and Q8 look like output and input buffers, respective. Are  
>> they ripe
>> for replacement with op-amps?
>>
>>  f) Question for the old-timers - why so many discrete  
>> transistors? Is it
>> that the op amps were expensive at the time? Op amps seem so much  
>> easier to
>> use (although they have their dangers).
>>
>>  My guess is that Q7 is acting as some sort of switch, shorting  
>> the top of
>> the cap to +15 volts (hence "charging up") the cap when the  
>> sawtooth needs
>> reset. The rest of the time Q7 is switched "off" and the expo  
>> converter
>> drains the charge from the cap. Does that sound like a good guess?
>>
>>  If so, I'm still puzzled on Q5 and Q6... but I must admit, I suck at
>> discrete transistors. I just recognize patterns I've seen in The  
>> Art of
>> Electronics. ;)
>>
>>  Maybe R29 is providing some "positive feedback" to make the  
>> comparator trip
>> faster?
>>
>>  I'm asking these questions since (a) it will provide debugging  
>> insights
>> when we get to that stage and (b) I want to make sure I don't lead my
>> student down the wrong path.
>>
>>  - Aaron, really a DSP/radar/image processing guy who got into  
>> analog synths
>> because they looked like fun
>>  _______________________________________________
>>  Synth-diy mailing list
>>  Synth-diy at dropmix.xs4all.nl
>>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Tue Apr 15 06:14:48 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 15 Apr 2008 00:14:48 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <2B73580A-BFB9-4E8E-BDE7-13978D6703C4@earthlink.net>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<2B73580A-BFB9-4E8E-BDE7-13978D6703C4@earthlink.net>
Message-ID: <E6791CE5-B4CD-42E2-88D9-63AB1C60AAA8@ece.gatech.edu>


On Apr 15, 2008, at 12:00 AM, mark verbos wrote:

> I'd suggest you look at the Kobol oscillator on my page
>
> http://www.simple-answer.com/DIY.html
>
> It's basically the same one that's in an SEM, but with OPamps  
> instead of those transistors for that buffer. Sadly, you'll notice  
> that it uses wider supply rails than +/-15, like the SEM. They also  
> used a 3086 for the NPNs in the core.
>
> Incidentally, Q4 does not invert the signal. Q5 and Q6 are a  
> comparator, R29 is adding positive feedback for hysteresis, Q8 and  
> Q9 are switching not buffering.
>
> My guess is that they used transistors because they are small and  
> cheap. It's probably a fatter, driftier sounding oscillator for it.  
> RSF used SSM chips in every part of the Kobol except the oscillator,  
> it's a GREAT sounding box.

Excellent - I guess you got this running without any troubles?

- Aaron


From mverbos at earthlink.net  Tue Apr 15 06:22:16 2008
From: mverbos at earthlink.net (mark verbos)
Date: Tue, 15 Apr 2008 00:22:16 -0400
Subject: [sdiy] On cloning, and the Oberheim VCO
In-Reply-To: <E6791CE5-B4CD-42E2-88D9-63AB1C60AAA8@ece.gatech.edu>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<87441170804141148k534b28f3hb5f645d1edd9b3f8@mail.gmail.com>
	<AFC4CAB3-7E8A-47CD-93AF-E52851A4E547@ece.gatech.edu>
	<916920440804141349q2533cfcax49e1d7d4c2b29754@mail.gmail.com>
	<2B73580A-BFB9-4E8E-BDE7-13978D6703C4@earthlink.net>
	<E6791CE5-B4CD-42E2-88D9-63AB1C60AAA8@ece.gatech.edu>
Message-ID: <A3077337-8E4C-45C2-AB21-2CD2A89A0FC1@earthlink.net>

It was a long time ago. I don't remember what troubles I had, but I  
did get it running.


mark



On Apr 15, 2008, at 12:14 AM, Aaron Lanterman wrote:
>
> On Apr 15, 2008, at 12:00 AM, mark verbos wrote:
>
>> I'd suggest you look at the Kobol oscillator on my page
>>
>> http://www.simple-answer.com/DIY.html
>>
>> It's basically the same one that's in an SEM, but with OPamps  
>> instead of those transistors for that buffer. Sadly, you'll notice  
>> that it uses wider supply rails than +/-15, like the SEM. They  
>> also used a 3086 for the NPNs in the core.
>>
>> Incidentally, Q4 does not invert the signal. Q5 and Q6 are a  
>> comparator, R29 is adding positive feedback for hysteresis, Q8 and  
>> Q9 are switching not buffering.
>>
>> My guess is that they used transistors because they are small and  
>> cheap. It's probably a fatter, driftier sounding oscillator for  
>> it. RSF used SSM chips in every part of the Kobol except the  
>> oscillator, it's a GREAT sounding box.
>
> Excellent - I guess you got this running without any troubles?
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Tue Apr 15 07:04:38 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 15 Apr 2008 01:04:38 -0400
Subject: [sdiy] Anyone tried cloning the Korg MS-20 VCO?
Message-ID: <EA6B20BD-1BC9-43DC-B157-083D5CE327AC@ece.gatech.edu>

It's got this weird thyristorish thing going on...

(I suggested cloning and tweaking it in a big list of suggested topics  
- although no one's picked it yet, I want to make sure to steer clear  
of gotchas.)

- Aaron


From lanterma at ece.gatech.edu  Tue Apr 15 07:13:09 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 15 Apr 2008 01:13:09 -0400
Subject: [sdiy] Modifying the SEM/Kobol VCO to not need that +18 V supply
Message-ID: <679880F0-A40A-4ACD-BA60-A205C8CC0A71@ece.gatech.edu>

Consider the Mark Verbos variant of the Kobol OSC schematic:

http://www.simple-answer.com/kobolosc.pdf

Could we get away with setting a lower reset point by using a  
different voltage than the rail at the emitter of the 3906 and the top  
of the 470 ohm resistor just to the left? So the TL082 wouldn't need  
to swing so far at the top? (Along those lines, if a LM329 will give  
me a nice 6.9V reference, will stacking two of them give me a nice  
13.8 V reference? Hmmm, that's probably outside of what a TL08x could  
swing with +/- 15 V supplies, so we'd probably need something else).

It seems that you wouldn't necessarily need to mess with the threshold  
value use by the comparitor.

- Aaron





From lanterma at ece.gatech.edu  Tue Apr 15 07:50:00 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 15 Apr 2008 01:50:00 -0400
Subject: [sdiy] Balance and Strobe pins on LM311 - what to do if you don't
	need them?
Message-ID: <8DA28799-904C-464F-BE32-632F01441307@ece.gatech.edu>

What's the best thing to do with these if you're not using any of the  
Balance/Strobe features?

I get the impression that people leave them unconnected; http://www.circuitstoday.com 
  on April 10, Light activated switch gives a circuit in which "The  
pin 5&6 (Balance & Balance/Strobe ) of IC LM311 are shorted to  
minimize the chance of oscillations," and the front page of the  
datasheet seems to suggest tying them both to the positive rail to  
"increase typical common mode slew."

- Aaron


From usenet at teply.info  Tue Apr 15 08:03:42 2008
From: usenet at teply.info (Florian E. Teply)
Date: Tue, 15 Apr 2008 08:03:42 +0200
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
In-Reply-To: <4803AD91.4090603@imt.net>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<4803AD91.4090603@imt.net>
Message-ID: <4804453E.6050108@teply.info>

Bob Weigel wrote:
> Congratulations!
> I believe what you have here is a machine which can actually process 
> carefully selected organic materials in order to produce an increasingly 
> wide variety of synthesis processes!  (ISA.... internally spawning 
> architecture!  It actually creates it's OWN UPGRADES!  You never have to 
> install them!) Is it equipped with a large number of pressure modulation 
> sensors?  While I understand your 'baby' is probably completely unique 
> in many ways, I think I may have witnessed models that have some similar 
> features.  :-)
> 
Well, in my opinion it lacks some decently controllable CV inputs AND it 
will most surely come without MIDI interface. No problem in the settings 
it is most likely to be used in though.
Yet what would take me back most is the lack of decent Amplitude 
Modulation capabilities as you can't modulate the Amplitude down to zero.

But apart from that, it's very decent SDIY work, so please don't go the 
way to featuritis ;-)

Congrats from here as well!!

> Aaron Lanterman wrote:
> 
>> Ship date April 4, 2008. Product delivered 9:03 PM.
>>
>> Name: Zachary Xavier Lanterman
>> Weight: 6 pounds and 14 ounces
>> Primary dimension: 20 inches
>> Features: Capable of making a wide variety high-pitched, frequency- 
>> modulated sounds.
>>
>> http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008 
>>
>>
>> This is a unique design, and not for sale. After building our first  
>> product, my design and construction partner, my wife (who did most of  
>> the construction), has absolutely no plans whatsoever to go into full- 
>> scale production.
>>



From Florian.Anwander at consol.de  Tue Apr 15 10:24:38 2008
From: Florian.Anwander at consol.de (Florian Anwander)
Date: Tue, 15 Apr 2008 10:24:38 +0200
Subject: [sdiy] 1v/Oct CV 'standards'?
In-Reply-To: <20080414203222.GO87399@moo.sysabend.org>
References: <4803b1fc.09a1660a.110f.ffffaf02@mx.google.com>
	<20080414203222.GO87399@moo.sysabend.org>
Message-ID: <48046646.8010607@consol.de>

Hi Tom

> Most synths 0volts=C, a notable exception is Moog where 0volts=F.

Most commercial synths I know have 0V = "lowest keyboard key". E.g. 
SH-101 or MonoPoly this is an F. Roland System 100 is a C.

Florian


From webmaster at joergschaaf.de  Tue Apr 15 12:53:07 2008
From: webmaster at joergschaaf.de (Joerg Schaaf)
Date: Tue, 15 Apr 2008 12:53:07 +0200
Subject: [sdiy] JH tripple chorus questions
References: <000801c87b7b$1a8f9370$0400a8c0@jhsilent>
	<47D5BBD1.7060005@hevanet.com>
	<003201c8834f$e41f2300$0400a8c0@jhsilent>
Message-ID: <lWSgCO9xWlRiaH9ug5PGqoiLowF2eltOntrzxMTI6ix@akmail>

Hi,

I meanwhile built the triple chorus and I am very surprised by the result. It sounds amazing. It is also very good as a chorus for e-guitars. But I have a serious problem with the BBD chips. I need multiple startups to get all delay lines to work. Mostly it starts just with one or two  lines only. Powering on and Off a couple of times starts all three lines but I would like to get them run instantly. Has someone experienced the same? Any help is highly appreciated.

Thanks in advance and thanks to Jurgen for his nice work.


Joerg

> The way I got the best stereo effect is described on my Triple Chorus page:
> http://www.jhaible.heim.at/triple_chorus/triple_chorus.html

> Stereo effect using individual outputs (390 kB mp3)
> http://www.jhaible.heim.at/triple_chorus/jh_string_ensemble_demo_stereo_r8b.mp3
> Yes, we can do Stereo, with the individual outputs.
> My first thought was to take the 3 individual outputs and mix them, one
> panned left, one center, and one right. But then the "Ensemble" effect falls
> apart, and the modulation sounds overly strong. I think you can do a lot of
> experiments with mixing the individual outputs, and will find interesting
> configurations.
> The above sound sample was made with a very simple setup, however:
> The full mix (main output) goes to one channel, and one individual channel
> goes to the other. The two channels are then panned almost (but not totally)
> left and right on the mixing desk.

> JH.


> ----- Original Message -----
> From: "NSSINC" <nssinc at hevanet.com>
> Cc: "SDIY" <synth-diy at dropmix.xs4all.nl>
> Sent: Monday, March 10, 2008 11:53 PM
> Subject: [sdiy] JH tripple chorus questions



> So I'm starting to think ahead to a front panel for my chorus (ahead of
> myself, still have not received the bbds) and I was wondering about a
> couple of ideas.

> -bringing the 'fast' 'slow' and 'waveform' pots to the front panel

> and

> -making a simple mixer to add on so I could have a 'balance' control for
> each output.

> I read JH says wide stereo spread ruins the effect, but I thought maybe
> a slight shift might be nice, something for the surround sound to play with.

> Anyone tried? Thoughts?

> Thanks,
> -Al


> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From elektrodwarf at yahoo.se  Tue Apr 15 14:30:12 2008
From: elektrodwarf at yahoo.se (Karl Ekdahl)
Date: Tue, 15 Apr 2008 12:30:12 +0000 (GMT)
Subject: SV: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location
	changes from Logan for 04/12/2008
Message-ID: <628180.86685.qm@web26213.mail.ukl.yahoo.com>

Yeah i would also have come if i knew...

Question: who arranged this? Why wasn't it on the list?

Karl

----- Ursprungligt meddelande ----
Fr?n: jeff brown <guitaricon at comcast.net>
Till: DIY SYNTH <synth-diy at dropmix.xs4all.nl>
Skickat: l?rdag 12 april 2008 22:54:02
?mne: Re:[sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location changes from Logan for 04/12/2008


----- Original Message ----- 
From: "jeff brown" <guitaricon at comcast.net>
To: "Logan Mitchell Sr" <prowlerraven32 at hotmail.com>
Sent: Saturday, April 12, 2008 9:25 PM
Subject: Re: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location 
changes from Logan for 04/12/2008


> Dang. I was out all day and just got this.  I live about 20 minutes from 
> there!
>
> Jeff
>
> ----- Original Message ----- 
> From: "Logan Mitchell Sr" <prowlerraven32 at hotmail.com>
> To: <fvanaman at gadgetland.net>
> Cc: <ronwest at gmail.com>; <davevosh at aol.com>; 
> <synth-diy at dropmix.xs4all.nl>; <dgrickert at hotmail.com>; 
> <gregae at comcast.net>; <analogue at hyperreal.org>
> Sent: Saturday, April 12, 2008 11:25 AM
> Subject: [sdiy] RE: Baltimore SDIY's 1st Meet-N-Greet Time & Location 
> changes from Logan for 04/12/2008
>
>
>>
>> 04/12/2008
>>
>> Hi Frank. There's been a location & time change. We'll now meet at the 
>> Golden Corral Restaurant on Chesapeake Drive at 2:00 pm today (Golden 
>> Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 
>> (410) 590-0270, 
>> (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02). 
>>  ).
>>
>> The manager was nice enough to provide us with a room that has electrical 
>> outlets for us to plug our stuff up. See the msg below that I sent to 
>> Dave VOSHyesterday. I may leave at little early to make some stops along 
>> the way. My cellphone number is 410-258-1875 & my pager number 
>> w/voice-mail is 1-800-815-5929. I'll notify the rest of the group. Hope 
>> to see you there. Ask for Tony the manager & I'll ask him to direct you 
>> to the room which we'll have the use of from 2:00 to 4:00 pm today. 
>> Thanks.
>>
>>
>> Logan
>>
>>
>> RE: Baltimore SDIY Meet & Greet Proposal from Logan?
>>
>>
>> From:
>> Logan Mitchell Sr (prowlerraven32 at hotmail.com)
>>
>>
>> Sent:
>> Fri 4/11/08 5:57 PM
>>
>>
>> To:
>> davevosh at aol.com
>>
>>
>> Dave
>>
>> The capability to dial my pager number from a payphone was taken away 
>> years ago. I asked them about us setting up in the booths but they have 
>> no electrical outlets in the booths. We may have to look for another 
>> location such as a library unless you still want to meet there and hope 
>> for the magic electric outlet to show up in another part of the diner. 
>> GOOD NEWS - Here's a better location that I go to with the family, Golden 
>> Corral Buffet & Grill 6701 Chesapeake Center Dr, Glen Burnie, MD 21060 
>> (410) 590-0270, 
>> (http://localsearch.live.com/localsearch/details.aspx?lid=YN403x7297613&qt=yp&what=golden+corral&where=baltimore%2c+maryland&s_cid=ansPhBkYp02). 
>> I just talked to Tony who is the manager at
>>
>> this location. I explained to him what we will be doing & that we need an 
>> outlet. He has a room that we can use from 2:00 pm to 4:00 pm as long as 
>> we are there by 2:00 pm tomorrow. I told him that we'll see him there 
>> tomorrow if you're for it, so bring your electronics. I also told him 
>> that we will be using headphones. Let me know what you think. This 
>> location is 2 blocks from Ritchie Highway.
>>
>> Logan
>>
>>
>>> From: fvanaman at gadgetland.net
>>> To: prowlerraven32 at hotmail.com
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>> Date: Sat, 12 Apr 2008 10:28:35 -0400
>>>
>>> 'morning--
>>>
>>> Looks like today's other festivities should be done in time for me to 
>>> make
>>> it down. I'm just about to go out a few hours - but was just wondering
>>> whether you settled on a more definite time this afternoon (and whether 
>>> or
>>> not it was still at the Mountain Road Double-T).
>>>
>>> I'm forwarding a copy to Jeff to see if he might be able to make it...
>>>
>>> Frank
>>>
>>> -----Original Message-----
>>> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
>>> Sent: Thursday, April 10, 2008 10:27 AM
>>> To: fvanaman at gadgetland.net
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>>
>>>
>>> Hi Frank. If you can make it let me know around 5:00 pm on Saturday. You 
>>> can
>>> call me on my pager with voice-mail at 1-800-815-5929. This system is
>>> limited to a 30 second recording time per voice-mail so if it cuts off 
>>> just
>>> call right back to leave another message. Leave me a callback number 
>>> too.
>>> Thanks & I'll keep you posted if you can't make it. Bring Jeff with you 
>>> if
>>> you can.
>>>
>>> Logan
>>> ________________________________
>>>
>>> From: fvanaman at gadgetland.net
>>> To: prowlerraven32 at hotmail.com
>>> Subject: RE: Baltimore SDIY Meet & Greet Proposal from Logan
>>> Date: Thu, 10 Apr 2008 09:47:03 -0400
>>>
>>>
>>>
>>>
>>>
>>> 'morning--
>>>
>>>
>>>
>>> Meeting (and eating) at a diner seems entirely appropriate for Synth
>>> D-I-Y'ers! :-) The Mountain Road Double-T would be cool. I'm 
>>> particularly
>>> fond of the Double-T north of Whitemarsh on Route 1, and sometimes meet 
>>> up
>>> with JeffK ('analoguejeff' on AH) over there.
>>>
>>>
>>>
>>> My Saturday is very full in the afternoon, and involves trundling my mom 
>>> to
>>> a couple things (which expands the time needed considerably), and also a
>>> couple of already-arranged house viewings, so I'm not sure I'll be done 
>>> in
>>> time for this one.
>>>
>>>
>>>
>>> Keep me posted, though, and I'll try my best,
>>>
>>>
>>>
>>> Frank
>>>
>>>
>>>
>>> ________________________________
>>>
>>> From: Logan Mitchell Sr [mailto:prowlerraven32 at hotmail.com]
>>> Sent: Wednesday, April 09, 2008 10:37 AM
>>> To: fvanaman at gadgetland.net; davevosh at aol.com; gregae at comcast.net;
>>> alfred.pear at gmail.com; dgrickert at hotmail.com; 
>>> prowlerraven32 at hotmail.com;
>>> ronwest at gmail.com
>>> Subject: Baltimore SDIY Meet & Greet Proposal from Logan
>>>
>>>
>>> 04/08/2008
>>>
>>> Hello to all & welcome to the first informal meeting of the newly formed
>>> Baltimore SDIY (Synthesizer Do It Yourself) Group. My name is Logan 
>>> Mitchell
>>> Sr and in November of 2007 I decided that it was time to try & form an 
>>> SDIY
>>> group here in Baltimore since all of the other groups seem to be located 
>>> in
>>> the upper Northeast or Northwest part of the country. Due to the 
>>> distances &
>>> today's increasing gas prices I find it difficult to attend any of these
>>> meetings. I really didn't know if anyone else would be interested in 
>>> doing
>>> something like this so I was afraid that it might not work but that has 
>>> now
>>> changed because you have decided to particpate in this endeavor of mine 
>>> for
>>> which I am very grateful.
>>>
>>> I am hoping that more s-d-i-yers join the group. For our first 
>>> face-to-face
>>> meeting I would like to propose that we meet at a restaurant which has a
>>> separate room similar to what the Double T Diner has. Here's a location 
>>> that
>>> closes off its Dining Room from 2:00 to 4:30pm but only on Mon thru 
>>> Fri -
>>> Double T Diner Co 1 Mountain Rd, Pasadena, MD 21122 (410) 766-9669
>>> (http://localsearch.live.com/localsearch/Details.aspx?what=diners&where=Glen
>>> +Burnie%2c+MD&tab=businessinfo&lid=YN404x7302805&qt=yp&s_cid=ansPhBkYp02&FOR
>>> M=LLDP).
>>>
>>> If you know of a better centralized location that's easy to get to then
>>> please let me know because I want everyone to be able to get there 
>>> easily &
>>> economically as well.
>>>
>>> Since I live in Northwest Baltimore 2 blocks from Pimlico Racetrack &
>>> everyone else lives in White Marsh and Upper Marlboro, it seems like 
>>> this
>>> may be a good central location for us to meet on a temporary or 
>>> permanent
>>> basis. Let me know what you think and maybe we can do a Meet & Greet 
>>> this
>>> Saturday (04/12/2008) say around 5:00 or 6:00 pm. Thanks.
>>>
>>> Logan
>>>
>>> Current members:
>>> Logan Mitchell Sr ProwlerRaven32 at hotmail.com (Baltimore MD) Alfred PEAR
>>> Alfred.Pear at gmail.com (Baltimore MD) Frank VANAMAN 
>>> FVanaman at gadgetland.net
>>> Dave VOSH DaveVosh at aol.com (Upper Marlboro MD) Ron WEST 
>>> Ron.West at gmail.com
>>> (White Marsh MD) Greg KIST GregAE at comcast.net (Columbia MD) David 
>>> RICKERT
>>> DGRickert at hotmail.com (Washington DC)
>>>
>>>
>>> ________________________________
>>>
>>> Get in touch in an instant. Get Windows Live Messenger now.
>>>
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 
>>> 4/9/2008
>>> 7:10 AM
>>>
>>>
>>>
>>> No virus found in this outgoing message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 
>>> 4/9/2008
>>> 4:20 PM
>>>
>>> _________________________________________________________________
>>> Use video conversation to talk face-to-face with Windows Live Messenger.
>>> http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGLM_WL
>>> _Refresh_messenger_video_042008
>>>
>>> No virus found in this incoming message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.11/1368 - Release Date: 
>>> 4/9/2008
>>> 4:20 PM
>>>
>>>
>>> No virus found in this outgoing message.
>>> Checked by AVG.
>>> Version: 7.5.519 / Virus Database: 269.22.12/1374 - Release Date: 
>>> 4/11/2008
>>> 4:59 PM
>>>
>>>
>>
>> _________________________________________________________________
>> Going green? See the top 12 foods to eat organic.
>> http://green.msn.com/galleries/photos/photos.aspx?gid=164&ocid=T003MSN51N1653A
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy





      __________________________________________________________
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J?mf?r pris p? flygbiljetter och hotellrum h?r:
http://shopping.yahoo.se/c-169901-resor-biljetter.html?partnerId=96914052



From stavrosgrigoriou at yahoo.com  Tue Apr 15 14:48:41 2008
From: stavrosgrigoriou at yahoo.com (Stavros Gregoriou)
Date: Tue, 15 Apr 2008 05:48:41 -0700 (PDT)
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
In-Reply-To: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
Message-ID: <530067.28393.qm@web54402.mail.yahoo.com>

CONGRATULATIONS!

Best Wishes

SG
--- Aaron Lanterman <lanterma at ece.gatech.edu> wrote:

> Ship date April 4, 2008. Product delivered 9:03 PM.
> 
> Name: Zachary Xavier Lanterman
> Weight: 6 pounds and 14 ounces
> Primary dimension: 20 inches
> Features: Capable of making a wide variety
> high-pitched, frequency- 
> modulated sounds.
> 
>
http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008
> 
> This is a unique design, and not for sale. After
> building our first  
> product, my design and construction partner, my wife
> (who did most of  
> the construction), has absolutely no plans
> whatsoever to go into full- 
> scale production.
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



      ____________________________________________________________________________________
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From harrybissell at wowway.com  Tue Apr 15 15:08:18 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Tue, 15 Apr 2008 08:08:18 -0500
Subject: [sdiy] Anyone tried cloning the Korg MS-20 VCO?
In-Reply-To: <EA6B20BD-1BC9-43DC-B157-083D5CE327AC@ece.gatech.edu>
References: <EA6B20BD-1BC9-43DC-B157-083D5CE327AC@ece.gatech.edu>
Message-ID: <20080415130740.M20915@wowway.com>

JH cloned it 
its in the JH-720 iirc

I've done a spice simulation for it

H^) harry



On Tue, 15 Apr 2008 01:04:38 -0400, Aaron Lanterman wrote
> It's got this weird thyristorish thing going on...
> 
> (I suggested cloning and tweaking it in a big list of suggested 
> topics  - although no one's picked it yet, I want to make sure to 
> steer clear  of gotchas.)
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From harrybissell at wowway.com  Tue Apr 15 15:10:28 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Tue, 15 Apr 2008 08:10:28 -0500
Subject: [sdiy] Balance and Strobe pins on LM311 - what to do if you don't
	need them?
In-Reply-To: <8DA28799-904C-464F-BE32-632F01441307@ece.gatech.edu>
References: <8DA28799-904C-464F-BE32-632F01441307@ece.gatech.edu>
Message-ID: <20080415130907.M72056@wowway.com>

The databook I have says to short pins 5-6
together if not used.

I did have an industrial application where having them
float did indeed cause a noise issue. I always short them now...

H^) harry


On Tue, 15 Apr 2008 01:50:00 -0400, Aaron Lanterman wrote
> What's the best thing to do with these if you're not using any of 
> the  Balance/Strobe features?
> 
> I get the impression that people leave them unconnected; 
> http://www.circuitstoday.com   on April 10, Light activated switch 
> gives a circuit in which "The  pin 5&6 (Balance & Balance/Strobe ) 
> of IC LM311 are shorted to  minimize the chance of oscillations," 
> and the front page of the  datasheet seems to suggest tying them 
> both to the positive rail to  "increase typical common mode slew."
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From richard.e.johnson at gmail.com  Tue Apr 15 17:36:49 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Tue, 15 Apr 2008 11:36:49 -0400
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
In-Reply-To: <4804453E.6050108@teply.info>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<4803AD91.4090603@imt.net> <4804453E.6050108@teply.info>
Message-ID: <be8b34180804150836w62b96223l652403a7c6df361c@mail.gmail.com>

Yes, but aren't those all minor quibbles in comparison to the awesome
flexibility of wetware analog? I mean look at Bobby McFerrin! :)

Congratulations!

On Tue, Apr 15, 2008 at 2:03 AM, Florian E. Teply <usenet at teply.info> wrote:
> Bob Weigel wrote:
>
> > Congratulations!
> > I believe what you have here is a machine which can actually process
> carefully selected organic materials in order to produce an increasingly
> wide variety of synthesis processes!  (ISA.... internally spawning
> architecture!  It actually creates it's OWN UPGRADES!  You never have to
> install them!) Is it equipped with a large number of pressure modulation
> sensors?  While I understand your 'baby' is probably completely unique in
> many ways, I think I may have witnessed models that have some similar
> features.  :-)
> >
> >
>  Well, in my opinion it lacks some decently controllable CV inputs AND it
> will most surely come without MIDI interface. No problem in the settings it
> is most likely to be used in though.
>  Yet what would take me back most is the lack of decent Amplitude Modulation
> capabilities as you can't modulate the Amplitude down to zero.
>
>  But apart from that, it's very decent SDIY work, so please don't go the way
> to featuritis ;-)
>
>  Congrats from here as well!!
>
>
> > Aaron Lanterman wrote:
> >
> >
> > > Ship date April 4, 2008. Product delivered 9:03 PM.
> > >
> > > Name: Zachary Xavier Lanterman
> > > Weight: 6 pounds and 14 ounces
> > > Primary dimension: 20 inches
> > > Features: Capable of making a wide variety high-pitched, frequency-
> modulated sounds.
> > >
> > >
> http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008
> > >
> > > This is a unique design, and not for sale. After building our first
> product, my design and construction partner, my wife (who did most of  the
> construction), has absolutely no plans whatsoever to go into full- scale
> production.
> > >
> > >
> >
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From subjectivity at hotmail.com  Tue Apr 15 19:51:33 2008
From: subjectivity at hotmail.com (Dan Snazelle)
Date: Tue, 15 Apr 2008 17:51:33 +0000
Subject: [sdiy] best frequency to cv (f/v) project for guitar??
Message-ID: <BAY144-W3276F3B9326356B7CA6978C8EB0@phx.gbl>


Hello there.

I have been trying in vain to find a suitable frequency to cv schematic or pcb for my modular. I'd like to be able to use guitar or voice to create CV signals.
they dont need to be super accurate.

 ANY info, links, or products would be appreciated.


thanks

--------------------------------------------
check out various dan music at:

http://www.myspace.com/lossnyc


http://www.soundclick.com/lossnyc.htm


http://www.indie911.com/dan-snazelle

(or for techno) http://www.myspace.com/snazelle




From Barry.L.Klein at wdc.com  Tue Apr 15 20:24:03 2008
From: Barry.L.Klein at wdc.com (Barry Klein)
Date: Tue, 15 Apr 2008 11:24:03 -0700
Subject: [sdiy] Announcing the release of my newest synth: The ZXL
In-Reply-To: <4803AD91.4090603@imt.net>
References: <D2A78826-3A18-4E29-8A83-0ABF967A9069@ece.gatech.edu>
	<4803AD91.4090603@imt.net>
Message-ID: <6B16794FD98610449F66759BBF503D40CEDF55@wdscexbe03.sc.wdc.com>

Forgot to mention its unique "Green Power" features.
But these have a messy/smelly downside...

Barry
 

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Bob Weigel
Sent: Monday, April 14, 2008 12:17 PM
To: Aaron Lanterman
Cc: SDIY
Subject: Re: [sdiy] Announcing the release of my newest synth: The ZXL

Congratulations! 

I believe what you have here is a machine which can actually process 
carefully selected organic materials in order to produce an increasingly 
wide variety of synthesis processes!  (ISA.... internally spawning 
architecture!  It actually creates it's OWN UPGRADES!  You never have to 
install them!) Is it equipped with a large number of pressure modulation 
sensors?  While I understand your 'baby' is probably completely unique 
in many ways, I think I may have witnessed models that have some similar 
features.  :-)

Aaron Lanterman wrote:

> Ship date April 4, 2008. Product delivered 9:03 PM.
>
> Name: Zachary Xavier Lanterman
> Weight: 6 pounds and 14 ounces
> Primary dimension: 20 inches
> Features: Capable of making a wide variety high-pitched, frequency- 
> modulated sounds.
>
>
http://www.kodakgallery.com/AlbumMenu.jsp?UV=990170731473_856837299503&view=
1&page=1&sort_order=0&albumsperpage=&ownerid=13598195403&navfolderid=2008 
>
>
> This is a unique design, and not for sale. After building our first  
> product, my design and construction partner, my wife (who did most of  
> the construction), has absolutely no plans whatsoever to go into full- 
> scale production.
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From hondareyte.luc at laposte.net  Wed Apr 16 10:36:58 2008
From: hondareyte.luc at laposte.net (Luc Hondareyte)
Date: Wed, 16 Apr 2008 10:36:58 +0200
Subject: [sdiy] best frequency to cv (f/v) project for guitar??
In-Reply-To: <BAY144-W3276F3B9326356B7CA6978C8EB0@phx.gbl>
References: <BAY144-W3276F3B9326356B7CA6978C8EB0@phx.gbl>
Message-ID: <1208335018.5534.6.camel@casper.acme>

Le mardi 15 avril 2008 ? 17:51 +0000, Dan Snazelle a ?crit :
> Hello there.
> 
> I have been trying in vain to find a suitable frequency to cv schematic or pcb for my modular. I'd like to be able to use guitar or voice to create CV signals.
> they dont need to be super accurate.
> 
>  ANY info, links, or products would be appreciated.
> 
> 
> thanks

Hi,
There is the Guitar CV interface from Robert Penfold
http://hammer.ampage.org/files/GuitarP2V.PDF 
http://electro-music.com/forum/viewtopic.php?highlight=guitar&t=14921

Luc





From jpdesroc at oricom.ca  Wed Apr 16 18:00:35 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Wed, 16 Apr 2008 12:00:35 -0400
Subject: [sdiy] Rene Shmitz Voltage controled ADSR (linear slope)
Message-ID: <380-22008431616035863@oricom.ca>

Hi list,

About this circuit:
http://www.synthdiy.com/show/file/?id=1409

Question:
If 0-5v pots would be placed at the Attack. Decay, Release inputs
would they be linear or log pots for good response?
And a table of 0-10v inputs vs slopes times 
would be very appreciated for the drafting of
the front panel A, D & R knobs timings (ex: 2msec to 10sec
positions..)
I'm thinking of using this design for
my next ADSR modules.
Anybody have info about my requests?

Thanks
Jean-Pierre Desrochers




From goldenechos at hotmail.com  Wed Apr 16 19:25:48 2008
From: goldenechos at hotmail.com (Anthony Rolando)
Date: Wed, 16 Apr 2008 13:25:48 -0400
Subject: [sdiy] FS: Linear Variable Power Supplies
In-Reply-To: <20080415130740.M20915@wowway.com>
References: <EA6B20BD-1BC9-43DC-B157-083D5CE327AC@ece.gatech.edu>
	<20080415130740.M20915@wowway.com>
Message-ID: <BAY119-W51430AFB8471434655557BB6EA0@phx.gbl>


I have 2 power supplies for sale.

One is identical to this unit:

http://cgi.ebay.com/MASTECH-VAR-0-30-VOLT-0-5-AMP-DC-POWER-SUPPLY-RC-REG_W0QQitemZ250236986453QQihZ015QQcategoryZ34061QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It is a Mastech 0-30V Regulated Linear Power Supply. IT IS BRAND NEW. I have never even taken it out of the box! I purchased it about a week ago, but I have since purchased another supply which better suits my needs. Asking $90.00 for that one.


The other unit I am selling is an older, VERY USED, Leader Variable Power Supply. 0-40V 2A. Pretty beat up, but it works. $20.00

Thanx,

Tony


_________________________________________________________________
More immediate than e-mail? Get instant access with Windows Live Messenger.
http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refresh_instantaccess_042008


From mr at analogue.org  Wed Apr 16 22:10:58 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Wed, 16 Apr 2008 22:10:58 +0200
Subject: [sdiy] In search of knobs...
Message-ID: <200804162010.m3GKA8Of000903@dropmix.xs4all.nl>

Hi,
inspired by the knobs on

Boss OC-2  -------> http://www.bossarea.com/images/OC2.jpg

and Buchla 200  --> http://buchla.com/historical/b200/images/259a.jpeg

I'm looking for a small black knob similar to the small Boss knob but 
with an indicator line like the Buchla's. Any good advice out there?

This would be a nice complement to "Moogish" knobs (like the big Boss 
knob or Tyco/Alcoswitch PKES series), but the ones without indicator 
line on the metal insert (like the small Boss knob or Tyco/Alcoswitch 
PKG series) are imho a bit too unergonomic in their minimal display 
of the knob setting.


/mr




From lanterma at ece.gatech.edu  Thu Apr 17 01:11:08 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 16 Apr 2008 19:11:08 -0400
Subject: [sdiy] Buchla 191 Sharp Cutoff Filter
In-Reply-To: <55371BCF-B51C-45A7-8AD3-41856D4FA593@ece.gatech.edu>
References: <55371BCF-B51C-45A7-8AD3-41856D4FA593@ece.gatech.edu>
Message-ID: <3E739FEE-C3BB-4EEF-8A64-2BA2A6D3BB27@ece.gatech.edu>

Anyone know what's in the guts of the sharp cutoff filter - i.e. what  
topology, are vactrols used, etc? I was sort of surprised to see a 4- 
pole Buchla filter!

I don't see the schematics on Magnus's site, and his is the most  
complete collection out there, so I'm guessing this is a rare beast?

- Aaron, currently going through a Buchla obsession


From subjectivity at hotmail.com  Thu Apr 17 01:45:37 2008
From: subjectivity at hotmail.com (Dan Snazelle)
Date: Wed, 16 Apr 2008 23:45:37 +0000
Subject: [sdiy] CA3094 replacements for EH guitar synth??
Message-ID: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>


hey there
i was wondering if I could use any other OTA in the EH micro synth pedal. 
it looks like a great schematic and would allow me to get a square wave.
 
or should i just buy some of them from ALL PARTS PIPE on ebay? (can anyone vouch for these?)
 
thanks
 
 

--------------------------------------------
check out various dan music at:

http://www.myspace.com/lossnyc  


http://www.soundclick.com/lossnyc.htm


http://www.indie911.com/dan-snazelle
(or for techno) http://www.myspace.com/snazelle 



From lanterma at ece.gatech.edu  Thu Apr 17 01:49:59 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 16 Apr 2008 19:49:59 -0400
Subject: [sdiy] Buchla 191 Sharp Cutoff Filter
In-Reply-To: <55371BCF-B51C-45A7-8AD3-41856D4FA593@ece.gatech.edu>
References: <55371BCF-B51C-45A7-8AD3-41856D4FA593@ece.gatech.edu>
Message-ID: <6E466D4C-E8AF-46BF-9C44-7190214BC8CC@ece.gatech.edu>

Anyone know what's in the guts of the sharp cutoff filter - i.e. what  
topology, are vactrols used, etc? I was sort of surprised to see a 4- 
pole Buchla filter!

I don't see the schematics on Magnus's site, and his is the most  
complete collection out there, so I'm guessing this is a rare beast?

- Aaron, currently going through a Buchla obsession


From pfperry at melbpc.org.au  Thu Apr 17 02:05:29 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 17 Apr 2008 10:05:29 +1000
Subject: [sdiy] CA3094 replacements for EH guitar synth??
In-Reply-To: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>
Message-ID: <001301c8a01e$bff49780$8501a8c0@ice9>

Well from the CA3094 data sheet:
"The CA3094 has the generic characteristics of the CA3080 operational amplifier directly coupled to an integral Darlington power transistor capable of sinking or driving currents up to 100mA. The gain of the differential input stage is proportional to the ampli?er bias current (IABC), permitting programmable variation of the integrated circuit sensitivity with either digital and/or analog programming signals. For example, at an IABC of 100?A, a 1mV change at the input will change the output from 0 to 100?A (typical). The CA3094 is intended for operation up to 24V and is especially useful for timing circuits, in automotive equipment, and in other applications where operation up to 24V is a primary design requirement"

So maybe a LM13700 would be OK.

Paul perry Melbourne Australia

-----Original Message-----

i was wondering if I could use any other OTA in the EH micro synth pedal. 
it looks like a great schematic and would allow me to get a square wave.
 
or should i just buy some of them from ALL PARTS PIPE on ebay? (can anyone vouch for these?)
 




From harrybissell at wowway.com  Thu Apr 17 02:17:30 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Wed, 16 Apr 2008 19:17:30 -0500
Subject: [sdiy] CA3094 replacements for EH guitar synth??
In-Reply-To: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>
References: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>
Message-ID: <20080417001519.M81983@wowway.com>

Its usually possible to sub the LM13600 or LM13700 and just change
the polarity of the inputs.  I've done the tracking filter of the
EH guitar synth this way. Its not a bad circuit but you might find it 
a little hard to build a quiet one.

H^) harry



On Wed, 16 Apr 2008 23:45:37 +0000, Dan Snazelle wrote
> hey there
> i was wondering if I could use any other OTA in the EH micro synth 
> pedal. it looks like a great schematic and would allow me to get a 
> square wave.
> 
> or should i just buy some of them from ALL PARTS PIPE on ebay? (can 
> anyone vouch for these?)
> 
> thanks
> 
> --------------------------------------------
> check out various dan music at:
> 
> http://www.myspace.com/lossnyc
> 
> http://www.soundclick.com/lossnyc.htm
> 
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From mverbos at earthlink.net  Thu Apr 17 02:24:51 2008
From: mverbos at earthlink.net (mark verbos)
Date: Wed, 16 Apr 2008 20:24:51 -0400
Subject: [sdiy] Buchla 191 Sharp Cutoff Filter
In-Reply-To: <3E739FEE-C3BB-4EEF-8A64-2BA2A6D3BB27@ece.gatech.edu>
References: <55371BCF-B51C-45A7-8AD3-41856D4FA593@ece.gatech.edu>
	<3E739FEE-C3BB-4EEF-8A64-2BA2A6D3BB27@ece.gatech.edu>
Message-ID: <906ED301-64A9-4A6E-B946-7FD3ADD6607F@earthlink.net>

It's not Vactrols. It uses transistors.



Mark




On Apr 16, 2008, at 7:11 PM, Aaron Lanterman wrote:
> Anyone know what's in the guts of the sharp cutoff filter - i.e.  
> what topology, are vactrols used, etc? I was sort of surprised to  
> see a 4-pole Buchla filter!
>
> I don't see the schematics on Magnus's site, and his is the most  
> complete collection out there, so I'm guessing this is a rare beast?
>
> - Aaron, currently going through a Buchla obsession
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From subjectivity at hotmail.com  Thu Apr 17 02:38:44 2008
From: subjectivity at hotmail.com (Dan Snazelle)
Date: Thu, 17 Apr 2008 00:38:44 +0000
Subject: [sdiy] CA3094 replacements for EH guitar synth??
In-Reply-To: <20080417001519.M81983@wowway.com>
References: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>
	<20080417001519.M81983@wowway.com>
Message-ID: <BAY144-W45525D8108EE641A20FF88C8E50@phx.gbl>


do you mean change the polarity as in Stick an inverter BEFORE the input or do you mean put the signal thats supposed to go into the minus input into the positive input?

and would this work with better with a 13700 or a 3080?

all i want to do is use the waveform outs and skip the rest of the circuit. I figure if i can tap into the square wave conversion i can feed a counter, maybe a 4024,etc, and then do all kinds of fun things getting audio to modulate other things. I am not going for precision or fast playing. i am going to combine this with a n envelope follower and a comparator so by combining all the different elements, i think it will add quite a bit to the original signal.  



thanks so much

-


From pfperry at melbpc.org.au  Thu Apr 17 02:43:10 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Thu, 17 Apr 2008 10:43:10 +1000
Subject: [sdiy] CA3094 replacements for EH guitar synth??
In-Reply-To: <20080417001519.M81983@wowway.com>
Message-ID: <001401c8a024$03136a50$8501a8c0@ice9>



Thanks for the heads-up on the polarity! I had no idea...

Paul perry Melbourne Australia

>Its usually possible to sub the LM13600 or LM13700 and just change
>the polarity of the inputs.  I've done the tracking filter of the
>EH guitar synth this way. Its not a bad circuit but you might find it 
>a little hard to build a quiet one.
>H^) harry






From lanterma at ece.gatech.edu  Thu Apr 17 04:50:23 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 16 Apr 2008 22:50:23 -0400
Subject: [sdiy] Buchla 194 Fixed Bandpass Filter analysis
Message-ID: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>

To get some practice analyzing circuits with transistors, I started  
looking at the Buchla 194 Fixed Bandpass Filter, as redrawn by Marjan  
Urekar:

http://members.tripod.com/urekarm/synth/buchla_bpf.pdf

The filters are all Sallen-Keys.

Numbering them from top down, the 1st filter is a 2nd order highpass,  
the next two are 2nd order lowpass followed by 2nd order highpass, and  
the 4th one is a 2nd order low-pass.

There are three emitter followers in the circuit; one as a buffer  
right at the beginning, and another two as part of lowpass filters in  
the 2nd and 3rd filter (from the top). The 1st and 4th filters, and  
the second filter section of the 2nd and 3rd, have two transistors  
forming a buffer in the "Sziklai" configuration, according to my  
trusty Horowitz and Hill.

The circuit runs off a single supply, so the transistors are biased at  
around 6 volts via 68K and 100K resistors. That's a little less than  
7.5, which would be halfway between the rails. A biasing network  
appears at the initial emitter follower, and also in the highpass  
filters (since they appear after a cap which would block the DC bias).

Questions:

1) The highpass S-K has a "feedback resistor" and a "resistor to  
ground." When I'm considering the "resistor to ground," should I think  
of the 68K and 100K biasing setup as both being resistors in parallel  
to "AC ground?" If so, my "to ground" resistor is actually 68K || 100K  
= 40K. (It's kind of embarassing to ask this, being an ECE prof, but  
it's been a long time since I actually dug into a transistor circuit -  
probably when I took the sophomore electronics class, uh, 17 years ago).

With this figured out, I can compute the cutoffs and Qs of the various  
filters.

2) All of the bases of the voltage buffers, except for the first one,  
have 10K resistors going into the bases. Why are those 10K resistors  
there?

3) There's a 2K2 and 100K voltage divider right at the beginning that  
attenuates the signal by a factor of 50, presumably to get the signal  
into the "linear small signal analysis" range. But... I don't see  
anywhere where the gain is brought back up at the end! Is there  
something I'm missing?

I thank the list, as always, for its collective wisdom!

I'm thinking it would be fun to create a modern version of this that  
just uses op amps and a split supply.

- Aaron







From mirwin at marketbridge.ca  Thu Apr 17 07:36:17 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Thu, 17 Apr 2008 01:36:17 -0400
Subject: [sdiy] CA3094 replacements for EH guitar synth??
References: <BAY144-W50393AB5D3171DE268F4BCC8EA0@phx.gbl>
Message-ID: <000c01c8a04c$f67858e0$e7db47d1@ca>

Can get CA3094E from www.smallbearelec.com.




----- Original Message -----
From: Dan Snazelle <subjectivity at hotmail.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 16, 2008 7:45 PM
Subject: [sdiy] CA3094 replacements for EH guitar synth??


>
> hey there
> i was wondering if I could use any other OTA in the EH micro synth pedal.
> it looks like a great schematic and would allow me to get a square wave.
>
> or should i just buy some of them from ALL PARTS PIPE on ebay? (can anyone
vouch for these?)
>
> thanks
>
>
>
> --------------------------------------------
> check out various dan music at:
>
> http://www.myspace.com/lossnyc
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From don at till.com  Thu Apr 17 08:21:03 2008
From: don at till.com (Donald Tillman)
Date: Wed, 16 Apr 2008 23:21:03 -0700
Subject: [sdiy] Buchla 194 Fixed Bandpass Filter analysis
In-Reply-To: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu> (message
	from Aaron Lanterman on Wed, 16 Apr 2008 22:50:23 -0400)
References: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>
Message-ID: <m28wzd0zow.fsf@till.com>

   > From: Aaron Lanterman <lanterma at ece.gatech.edu>
   > Date: Wed, 16 Apr 2008 22:50:23 -0400

Hey Aaron,

   > To get some practice analyzing circuits with transistors, I started  
   > looking at the Buchla 194 Fixed Bandpass Filter, as redrawn by Marjan  
   > Urekar:
   > 
   > http://members.tripod.com/urekarm/synth/buchla_bpf.pdf
   > 
   > 1) The highpass S-K has a "feedback resistor" and a "resistor to
   > ground." When I'm considering the "resistor to ground," should I
   > think of the 68K and 100K biasing setup as both being resistors
   > in parallel to "AC ground?" If so, my "to ground" resistor is
   > actually 68K || 100K = 40K.

To AC and DC ground, yeah.  It's called a Thevenin equivalent
(Wikipedia has an entry for Thevenin's Theorem).  A resistor divider
between two voltage sources such as the power rails is equivalent to a
single resistor, of value equal to the parallel combination of the
two, wired to a single voltage in between.

So a 68K/100K resistor pair across a 15 volt power supply is
equivalent to a 40.5K conneted to a 6.0 V supply.

   > With this figured out, I can compute the cutoffs and Qs of the
   > various filters.

Yes.

   > 2) All of the bases of the voltage buffers, except for the first one,  
   > have 10K resistors going into the bases. Why are those 10K resistors  
   > there?

Discrete emitter followers often include base resistors to hold down
high frequency oscillations.  Similar to the dominant pole in opamp
circuits.

   > 3) There's a 2K2 and 100K voltage divider right at the beginning
   > that attenuates the signal by a factor of 50, presumably to get
   > the signal into the "linear small signal analysis"
   > range. But... I don't see anywhere where the gain is brought back
   > up at the end! Is there something I'm missing?

The resistor values are actually the other way around; the circuit
only attenutates the input signal by 1/50th.  The 100K resistor keeps
the input cap from floating and prevents loud pops when you connect a
ground-centered input, and the 2.2K protects the transistor from nasty
hight current transients.

   > I thank the list, as always, for its collective wisdom!
   > 
   > I'm thinking it would be fun to create a modern version of this
   > that just uses op amps and a split supply.

No no no; the discrete version is lots more fun.

   -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com


From somnium7 at gmail.com  Thu Apr 17 09:24:21 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Thu, 17 Apr 2008 03:24:21 -0400
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <001c01c89767$941b6c70$6600a8c0@john>
References: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
	<001c01c89767$941b6c70$6600a8c0@john>
Message-ID: <916920440804170024r1e7a091ao12e68389f30ee7d8@mail.gmail.com>

Since this one is on sale, I decided to give it a try.

Thanks for the tip John.

Mike

On Sat, Apr 5, 2008 at 5:54 PM, John Loffink <jloffink at austin.rr.com> wrote:
> Hakko 808.  Don't forget to buy the stand which is sold separately. The
>  combination will run less than $200.
>
>  http://www.tequipment.net/Hakko808.html
>
>  John Loffink
>  The Microtonal Synthesis Web Site
>  http://www.microtonal-synthesis.com
>  The Wavemakers Synthesizer Web Site
>  http://www.wavemakers-synth.com
>
>
>
>
>  > -----Original Message-----
>  > From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>  > bounces at dropmix.xs4all.nl] On Behalf Of mike ruberto
>  > Sent: Saturday, April 05, 2008 4:00 PM
>  > To: Veronica Merryfield
>  > Cc: synth-diy at dropmix.xs4all.nl
>  > Subject: Re: [sdiy] Desoldering/Rework Stations
>  >
>  > I'm primarily looking for vacuum desoldering for thru-hole components.
>  > It's 99% of what I work on. Something more like this...
>  > http://www.mcmelectronics.com/product/WDD81VIL
>  >
>  > Preferably less expensive if possible...
>  >
>
>


From jdec at mindspring.com  Thu Apr 17 13:48:02 2008
From: jdec at mindspring.com (BrightBoy)
Date: Thu, 17 Apr 2008 07:48:02 -0400 (GMT-04:00)
Subject: [sdiy] Desoldering/Rework Stations
Message-ID: <11423934.1208432882800.JavaMail.root@mswamui-valley.atl.sa.earthlink.net>

It's even cheaper here:

http://www.kiesub.com/prostores/servlet/-strse-8/Hakko-808-Desoldering-Gun/Detail

Cheers,

Jeff

-----Original Message-----
>From: mike ruberto <somnium7 at gmail.com>
>Sent: Apr 17, 2008 3:24 AM
>To: John Loffink <jloffink at austin.rr.com>, synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] Desoldering/Rework Stations
>
>Since this one is on sale, I decided to give it a try.
>
>Thanks for the tip John.
>
>Mike
>
>On Sat, Apr 5, 2008 at 5:54 PM, John Loffink <jloffink at austin.rr.com> wrote:
>> Hakko 808.  Don't forget to buy the stand which is sold separately. The
>>  combination will run less than $200.
>>
>>  http://www.tequipment.net/Hakko808.html
>>
>>  John Loffink
>>  The Microtonal Synthesis Web Site
>>  http://www.microtonal-synthesis.com
>>  The Wavemakers Synthesizer Web Site
>>  http://www.wavemakers-synth.com
>>
>>
>>
>>
>>  > -----Original Message-----
>>  > From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>>  > bounces at dropmix.xs4all.nl] On Behalf Of mike ruberto
>>  > Sent: Saturday, April 05, 2008 4:00 PM
>>  > To: Veronica Merryfield
>>  > Cc: synth-diy at dropmix.xs4all.nl
>>  > Subject: Re: [sdiy] Desoldering/Rework Stations
>>  >
>>  > I'm primarily looking for vacuum desoldering for thru-hole components.
>>  > It's 99% of what I work on. Something more like this...
>>  > http://www.mcmelectronics.com/product/WDD81VIL
>>  >
>>  > Preferably less expensive if possible...
>>  >
>>
>>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy





From dougt55 at yahoo.com  Thu Apr 17 14:14:45 2008
From: dougt55 at yahoo.com (Doug Terrebonne)
Date: Thu, 17 Apr 2008 05:14:45 -0700 (PDT)
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <11423934.1208432882800.JavaMail.root@mswamui-valley.atl.sa.earthlink.net>
Message-ID: <357604.95602.qm@web81203.mail.mud.yahoo.com>

If you have a Fry's nearby I got mine there for $150...

Doug

--- BrightBoy <jdec at mindspring.com> wrote:

> It's even cheaper here:
> 
>
http://www.kiesub.com/prostores/servlet/-strse-8/Hakko-808-Desoldering-Gun/Detail
> 
> Cheers,
> 
> Jeff
> 
> -----Original Message-----
> >From: mike ruberto <somnium7 at gmail.com>
> >Sent: Apr 17, 2008 3:24 AM
> >To: John Loffink <jloffink at austin.rr.com>,
> synth-diy at dropmix.xs4all.nl
> >Subject: Re: [sdiy] Desoldering/Rework Stations
> >
> >Since this one is on sale, I decided to give it a try.
> >
> >Thanks for the tip John.
> >
> >Mike
> >
> >On Sat, Apr 5, 2008 at 5:54 PM, John Loffink
> <jloffink at austin.rr.com> wrote:
> >> Hakko 808.  Don't forget to buy the stand which is sold
> separately. The
> >>  combination will run less than $200.
> >>
> >>  http://www.tequipment.net/Hakko808.html
> >>
> >>  John Loffink
> >>  The Microtonal Synthesis Web Site
> >>  http://www.microtonal-synthesis.com
> >>  The Wavemakers Synthesizer Web Site
> >>  http://www.wavemakers-synth.com
> >>
> >>
> >>
> >>
> >>  > -----Original Message-----
> >>  > From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> >>  > bounces at dropmix.xs4all.nl] On Behalf Of mike ruberto
> >>  > Sent: Saturday, April 05, 2008 4:00 PM
> >>  > To: Veronica Merryfield
> >>  > Cc: synth-diy at dropmix.xs4all.nl
> >>  > Subject: Re: [sdiy] Desoldering/Rework Stations
> >>  >
> >>  > I'm primarily looking for vacuum desoldering for thru-hole
> components.
> >>  > It's 99% of what I work on. Something more like this...
> >>  > http://www.mcmelectronics.com/product/WDD81VIL
> >>  >
> >>  > Preferably less expensive if possible...
> >>  >
> >>
> >>
> >_______________________________________________
> >Synth-diy mailing list
> >Synth-diy at dropmix.xs4all.nl
> >http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From jpdesroc at oricom.ca  Thu Apr 17 17:15:37 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Thu, 17 Apr 2008 11:15:37 -0400
Subject: [sdiy] How to mount PCB's behind front panels..
Message-ID: <380-220084417151537244@oricom.ca>

Hi list,

Does anybody have pictures of how
they made their fixtures to hold the PCB
behind 'synthesizers.com' type front panels?
I'm curious to see the brackets, holding screws,
aluminium sheets retainers, etc..

Cheers,
J-Pierre




From dlmanley at sonic.net  Thu Apr 17 18:29:43 2008
From: dlmanley at sonic.net (Dave Manley)
Date: Thu, 17 Apr 2008 09:29:43 -0700
Subject: [sdiy] OT: RIP Edward Lorenz 
Message-ID: <48077AF7.1090005@sonic.net>

For followers of chaos theory, one of the leaders in the field has died:

http://web.mit.edu/newsoffice/2008/obit-lorenz-0416.html

http://en.wikipedia.org/wiki/Lorenz_attractor

-Dave



From mverbos at earthlink.net  Thu Apr 17 19:53:47 2008
From: mverbos at earthlink.net (mark verbos)
Date: Thu, 17 Apr 2008 13:53:47 -0400
Subject: [sdiy] Buchla 194 Fixed Bandpass Filter analysis
In-Reply-To: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>
References: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>
Message-ID: <BCF0D687-C777-45C1-BD58-599F28408C0E@earthlink.net>

Buchla did just that. It's called the 294 4 channel bandpass filter.


Mark




On Apr 16, 2008, at 10:50 PM, Aaron Lanterman wrote:

>
> I thank the list, as always, for its collective wisdom!
>
> I'm thinking it would be fun to create a modern version of this  
> that just uses op amps and a split supply.
>
> - Aaron
>
>
>


From richard at atkinsoft.com  Thu Apr 17 20:25:50 2008
From: richard at atkinsoft.com (Richard Atkinson)
Date: 17 Apr 2008 19:25:50 +0100
Subject: [sdiy] Adding sync to dual oscillator Yamaha CS synths
In-Reply-To: <BCF0D687-C777-45C1-BD58-599F28408C0E@earthlink.net>
References: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>
	<BCF0D687-C777-45C1-BD58-599F28408C0E@earthlink.net>
Message-ID: <Prayer.1.1.0.0804171925500.30004@hermes-1.csi.cam.ac.uk>

Hi all,

I've been growing tired of the wimpy sound of my Yamaha CS-15D. Apart from 
adding extra controls for Channel I, I thought I'd have a go at adding 
oscillator sync.

Has anyone ever tried this before? I'm not aware of any CS series 
instruments that have it as standard, but it looks like it might be 
possible. I had a look at the Yamaha IC Guide Book:

http://www.loscha.com/miller/Yamaha_IC_Data_Book.pdf

iG00153 VCO III is on pages 35 & 36. It looks like the VCO integrator 
capacitor at pin 14 of the first VCO could be discharged to GND by 
connecting a transistor across it, controlled by the one-shot 
multi-vibrator waveform at pin 10 of the second VCO. The waveform actually 
available at pin 10 of an iG00153 may need some buffering and/or inversion 
to perform this task, but it strikes me it should be possible.

Richard



From somnium7 at gmail.com  Thu Apr 17 22:47:00 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Thu, 17 Apr 2008 16:47:00 -0400
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <87441170804171109h2ba0ae5nc11ed05434cb5687@mail.gmail.com>
References: <916920440804051400n5a844f87x69b1f3bcab48ebc6@mail.gmail.com>
	<001c01c89767$941b6c70$6600a8c0@john>
	<916920440804170024r1e7a091ao12e68389f30ee7d8@mail.gmail.com>
	<87441170804171109h2ba0ae5nc11ed05434cb5687@mail.gmail.com>
Message-ID: <916920440804171347q206f82acte7eac9c6af83dda9@mail.gmail.com>

> Hey Mike,
>
>
> Just a side note about the Hakko brand: I bought an inexpensive Hakko
> soldering iron (about $60) two years ago at Fry's, and it has performed
> flawlessly. To tell you the truth, I don't even see wear on the tip, and
> fully expect it (the tip) to easily last another 2 - 3 years. Good stuff +
> reasonable price = Happy Servo.
>
>
> Tim (another happy customer) Servo
> --
> "Imagination is more important than knowledge." - Albert Einstein

That's good to know. I ordered a few extra tips to be prepared but
hopefully I'll get the same mileage as your iron's tips. Of course I'm
sure I wouldn't go through tips so much if I didn't use my iron as a
prybar ;-)


From mr at analogue.org  Thu Apr 17 23:13:27 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Thu, 17 Apr 2008 23:13:27 +0200
Subject: [sdiy] Spectrol 148/149 vs 248/249 vs Bourns 90s...
Message-ID: <200804172112.m3HLCeHt006481@dropmix.xs4all.nl>

Hi,

I'm trying to make a pot decision between 
Spectrol and Bourns, and also find ways of 
getting them to a decent price (I'm in Europe), 
but I'm literally drowning in numbers and letters 
and prices and models... and people's varying opinions.

Spectrol 148/149 series seem generally more 
expensive than Bourns 90 series, but there's also 
a Spectrol 248/249 series which seems to be some 
cheaper version of the 148/149. Any more knowledge or general opinions on this?

I'm quite open to any type of do?s and don't?s right now, I'm afraid. :-)

Thanks,

/mr





From lightburnx at yahoo.com  Fri Apr 18 00:43:23 2008
From: lightburnx at yahoo.com (Kyle Stephens)
Date: Thu, 17 Apr 2008 15:43:23 -0700 (PDT)
Subject: [sdiy] OT: RIP Edward Lorenz 
In-Reply-To: <48077AF7.1090005@sonic.net>
Message-ID: <465899.3034.qm@web33908.mail.mud.yahoo.com>

In memoriam, one could build one of these:

http://www.schnozzle.org/~paulh/misc/lorenz.htm

Have the parts, haven't put one together myself yet...


--- Dave Manley <dlmanley at sonic.net> wrote:

> For followers of chaos theory, one of the leaders in
> the field has died:
> 
>
http://web.mit.edu/newsoffice/2008/obit-lorenz-0416.html
> 
> http://en.wikipedia.org/wiki/Lorenz_attractor
> 
> -Dave
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



      ____________________________________________________________________________________
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From pfperry at melbpc.org.au  Fri Apr 18 02:04:32 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Fri, 18 Apr 2008 10:04:32 +1000
Subject: [sdiy] Desoldering/Rework Stations
In-Reply-To: <916920440804171347q206f82acte7eac9c6af83dda9@mail.gmail.com>
Message-ID: <002701c8a0e7$c7c9cd80$8501a8c0@ice9>

So far as irons themselves go, I'm very happy with the secondhand hakkos
from a government auction.
Have replaced the tips a couple of times over the years - but this is a
manufacturing environment.

I never use them as prybars - that is the sure way to wreck any iron - but I
don't NEED to, because I have a kit of stainless steel dental tools from one
of the surplus stores. Dental picks are just fantastic for repair work.

I bought a cheap KADA SMT rework from Hong Kong - haven't needed to use it
yet, but the guy who borrowed it liked it so much that his workplace bought
one as well.

Paul perry Melbourne asutralia

-----Original Message-----
>> Just a side note about the Hakko brand: I bought an inexpensive Hakko
>> soldering iron (about $60) two years ago at Fry's, and it has performed
>> flawlessly. To tell you the truth, I don't even see wear on the tip, and
>> fully expect it (the tip) to easily last another 2 - 3 years. Good stuff
>> reasonable price = Happy Servo.
>hat's good to know. I ordered a few extra tips to be prepared but
>hopefully I'll get the same mileage as your iron's tips. Of course I'm
>sure I wouldn't go through tips so much if I didn't use my iron as a
>prybar ;-)



From synth1 at airmail.net  Fri Apr 18 05:11:11 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Thu, 17 Apr 2008 22:11:11 -0500
Subject: [sdiy] Spectrol 148/149 vs 248/249 vs Bourns 90s...
References: <200804172112.m3HLCeHt006481@dropmix.xs4all.nl>
Message-ID: <016a01c8a101$dabeb670$b000a8c0@curley>

The main issue is that (at least in US), you cannot find "off-the-shelf" 
*log pots* in Spectrol 148/149. So, you have to use the 248J part, that has 
plastic threads (not that big a deal, but annoying).

Paul S.

----- Original Message ----- 
From: "Mattias Rickardsson" <mr at analogue.org>
To: "Synth-DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, April 17, 2008 4:13 PM
Subject: [sdiy] Spectrol 148/149 vs 248/249 vs Bourns 90s...


Hi,

I'm trying to make a pot decision between
Spectrol and Bourns, and also find ways of
getting them to a decent price (I'm in Europe),
but I'm literally drowning in numbers and letters
and prices and models... and people's varying opinions.

Spectrol 148/149 series seem generally more
expensive than Bourns 90 series, but there's also
a Spectrol 248/249 series which seems to be some
cheaper version of the 148/149. Any more knowledge or general opinions on 
this?

I'm quite open to any type of do?s and don't?s right now, I'm afraid. :-)

Thanks,

/mr



_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From harrybissell at wowway.com  Fri Apr 18 14:56:46 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Fri, 18 Apr 2008 07:56:46 -0500
Subject: [sdiy] CA3094 replacements for EH guitar synth??
In-Reply-To: <001401c8a024$03136a50$8501a8c0@ice9>
References: <20080417001519.M81983@wowway.com>
	<001401c8a024$03136a50$8501a8c0@ice9>
Message-ID: <20080418125520.M79190@wowway.com>

The polarity is a little misleading... the output
transistor has both the collector and emitter available...
the LM13700 has only an emitter. The CA3094 is a little
more flexible in that way. In the EH application, it can
be gotten around...


H^)  harry


On Thu, 17 Apr 2008 10:43:10 +1000, Paul Perry wrote
> Thanks for the heads-up on the polarity! I had no idea...
> 
> Paul perry Melbourne Australia
> 
> >Its usually possible to sub the LM13600 or LM13700 and just change
> >the polarity of the inputs.  I've done the tracking filter of the
> >EH guitar synth this way. Its not a bad circuit but you might find it 
> >a little hard to build a quiet one.
> >H^) harry
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From james at ticalun.net  Fri Apr 18 16:21:08 2008
From: james at ticalun.net (James R. Coplin)
Date: Fri, 18 Apr 2008 09:21:08 -0500
Subject: [sdiy] asm-1 power draw...
Message-ID: <20080418072115.5A18641A@dm02.mta.everyone.net>

Does anyone know what the actual draw of the ASM-1 project is?  I'm finally
getting around to working on mine and would like to add some functionality
and I want to make sure I get a large enough supply.

James R. Coplin
(???)

***************************************
Work is the Curse of the Drinking Class
***************************************
 





From thomas at thomaslaskowski.com  Fri Apr 18 16:56:13 2008
From: thomas at thomaslaskowski.com (thomas at thomaslaskowski.com)
Date: Fri, 18 Apr 2008 09:56:13 -0500
Subject: [sdiy] Re: asm-1 power draw...
In-Reply-To: <20080418072115.5A18641A@dm02.mta.everyone.net>
References: <20080418072115.5A18641A@dm02.mta.everyone.net>
Message-ID: <S388577AbYDRO4N/20080418145613Z+48405@ams12.chi.affinity.com>

200ma on the positive rail and 200ma on the negative rail will be enough for 
the ASM-1.  You will probably need more if you want to add additional 
modules. 

 -Tom 

James R. Coplin writes: 

> Does anyone know what the actual draw of the ASM-1 project is?  I'm finally
> getting around to working on mine and would like to add some functionality
> and I want to make sure I get a large enough supply. 
> 
> James R. Coplin
> (郭杰明) 
> 
> ***************************************
> Work is the Curse of the Drinking Class
> ***************************************
>   
> 
>  
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
 



From yves.usson at imag.fr  Fri Apr 18 18:16:21 2008
From: yves.usson at imag.fr (yves usson)
Date: Fri, 18 Apr 2008 18:16:21 +0200
Subject: [sdiy] Adding sync to dual oscillator Yamaha CS synths
In-Reply-To: <Prayer.1.1.0.0804171925500.30004@hermes-1.csi.cam.ac.uk>
References: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>	<BCF0D687-C777-45C1-BD58-599F28408C0E@earthlink.net>
	<Prayer.1.1.0.0804171925500.30004@hermes-1.csi.cam.ac.uk>
Message-ID: <4808C955.5060900@imag.fr>

Yes it's been done by Erik G. in 1999 for his CS15. 
http://home.swipnet.se/ericg/
Since the mod files are no longer available at his site, I will send 
them to you directly.

Cheers

Yves Yusynth

Richard Atkinson a ?crit :
> Hi all,
> 
> I've been growing tired of the wimpy sound of my Yamaha CS-15D. Apart 
> from adding extra controls for Channel I, I thought I'd have a go at 
> adding oscillator sync.
> 
> Has anyone ever tried this before? I'm not aware of any CS series 
> instruments that have it as standard, but it looks like it might be 
> possible. I had a look at the Yamaha IC Guide Book:
> 
> http://www.loscha.com/miller/Yamaha_IC_Data_Book.pdf
> 
> iG00153 VCO III is on pages 35 & 36. It looks like the VCO integrator 
> capacitor at pin 14 of the first VCO could be discharged to GND by 
> connecting a transistor across it, controlled by the one-shot 
> multi-vibrator waveform at pin 10 of the second VCO. The waveform 
> actually available at pin 10 of an iG00153 may need some buffering 
> and/or inversion to perform this task, but it strikes me it should be 
> possible.
> 
> Richard
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From johnspeth at yahoo.com  Fri Apr 18 18:21:15 2008
From: johnspeth at yahoo.com (johnspeth at yahoo.com)
Date: Fri, 18 Apr 2008 09:21:15 -0700 (PDT)
Subject: [sdiy] Gibson Robot Guitar teardown
Message-ID: <56869.85971.qm@web53301.mail.re2.yahoo.com>

Hi group-

I was privileged to attend the Embedded Systems Conference in San Jose this week.  Yesterday they did a live teardown of the Gibson Robot Guitar, a Les Paul with automatic tuning.  It was worth relating what I saw:

So you just spent $2500 on a Les Paul.  If you're like me, you're ultra curious about how it works but risking voiding your warranty keeps that knowledge bottled up.  It was a rare occasion to see somebody else take that risk.

Gibson did a great job of preserving the integrity of the Les Paul.  You could remove the auto-tune stuff and you'd still have a true-blue Les Paul without any extra holes, cavities, or anything.

There is a one knob module with a battery that is recharged with a special external guitar cable device.  The module takes the place of one of the volume pots.  In that module is a C8051F120 that handles the UI (a terribly overloaded knob with only push and turn capability), string frequency measurement, and tuning peg motor control.  The module contains power supply, battery charging, a CAN comm chip, and analog interface circutry.  String frequency is measured by 6 piezo devices in a special bridge connected to the knob module with a flex ribbon cable.

On to the head.  The strings provide a method to provide power and redundant communication to the motors and controller on the head.  A special string tail price provides the necessary insulation to avoid shorts.  Obviously, the frets will bypass that system.  Each tuning peg has a tiny stepper motor, a tiny closed drive reducer, and a main drive gear that can be engaged/disengaged by the user per tuning peg.  All six tuning pags are driven by a stepper motor controller module centered around another C8051F120.  Communication is via CAN (automotive!).  

Here's the zinger: The stepper motor and drive reducer is coupled with a rubber belt!!  Talk about weak links!  It's been my experience that rubber cracks with heat, it will eventually stretch to a permanant oversized shape, and with time will someday turn to goo.  If you're gonna buy this guitar, buy a lifetime supply of belts and freeze them for later use.

See more at: http://www.eetimes.com/galleries/slideShow.jhtml?galleryID=11&imageID=1

JJS


      ____________________________________________________________________________________
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know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From johnspeth at yahoo.com  Fri Apr 18 18:31:54 2008
From: johnspeth at yahoo.com (johnspeth at yahoo.com)
Date: Fri, 18 Apr 2008 09:31:54 -0700 (PDT)
Subject: [sdiy] Line6 ToneCore DIY
Message-ID: <950433.42845.qm@web53302.mail.re2.yahoo.com>

Hi group-

In another email I sent to the list describing the Gibson Robot guitar teardown, I mentioned I attended the ESC this week.  I was also able to attend a one hour Freescale seminar that described the upcoming ToneCore products from Line6.  You can, with very modest expense, obtain a very nice audio DSP development hardware platform from Line6.  Using the free Freescale Symphony Audio DSP IDE, you can develop your own DSP algorithms/software for use on the ToneCore modules.  You can buy experimenter grade modules, load your software into them, and use them in place and with Line6s' modules.

I think someone brought this topic up several months ago.  I got a chance to see it in action.

And I got a chance to meet a fellow list member, Byron Jacquot, at this seminar and ESC.  It was a pleasure to meet you Byron.  Thanks for making the effort to introduce yourself.

JJS


      ____________________________________________________________________________________
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From magnus at rubidium.dyndns.org  Fri Apr 18 21:13:51 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Fri, 18 Apr 2008 21:13:51 +0200 (CEST)
Subject: [sdiy] asm-1 power draw...
In-Reply-To: <20080418072115.5A18641A@dm02.mta.everyone.net>
References: <20080418072115.5A18641A@dm02.mta.everyone.net>
Message-ID: <20080418.211351.128088246204302874.cfmd@bredband.net>

From: "James R. Coplin" <james at ticalun.net>
Subject: [sdiy] asm-1 power draw...
Date: Fri, 18 Apr 2008 09:21:08 -0500
Message-ID: <20080418072115.5A18641A at dm02.mta.everyone.net>

> Does anyone know what the actual draw of the ASM-1 project is?  I'm finally
> getting around to working on mine and would like to add some functionality
> and I want to make sure I get a large enough supply.

About 100 mA as I recall it.

Cheers,
Magnus


From romeo.fahl at gmail.com  Sat Apr 19 02:44:30 2008
From: romeo.fahl at gmail.com (Romeo Fahl)
Date: Fri, 18 Apr 2008 17:44:30 -0700
Subject: [sdiy] Splitting sound field into 6 zones?
Message-ID: <d3a114240804181744s3e4163c7yf0738c11e21f78e7@mail.gmail.com>

I'm being asked to play a set in a six speaker surround sound setup in
a few months.  Is there a simple way (using a joystick) to position
the sound in that kind of a setup? I'm used to thinking of 2 channel
and quad systems, but using 1 joystick to pan to 6 outputs has me a
little baffled.

R.


From jason at redfish.net  Sat Apr 19 03:00:37 2008
From: jason at redfish.net (Jason Proctor)
Date: Fri, 18 Apr 2008 18:00:37 -0700
Subject: [sdiy] Splitting sound field into 6 zones?
In-Reply-To: <d3a114240804181744s3e4163c7yf0738c11e21f78e7@mail.gmail.com>
References: <d3a114240804181744s3e4163c7yf0738c11e21f78e7@mail.gmail.com>
Message-ID: <a06200768c42ef3dd9fc3@[10.0.1.201]>

if that 6 speaker setup is really 4 + sub + centre, then you can 
treat it as (easily joystickable) quadraphonic and then have separate 
mixes for the sub and centre.

if not, a Wiard JAG provides 10 CV outputs based on the position of a 
joystick :-)

http://www.wiard.com/1200/JAG/jag.html



>I'm being asked to play a set in a six speaker surround sound setup in
>a few months.  Is there a simple way (using a joystick) to position
>the sound in that kind of a setup? I'm used to thinking of 2 channel
>and quad systems, but using 1 joystick to pan to 6 outputs has me a
>little baffled.
>
>R.
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From batzman-nr at all-electric.com  Sat Apr 19 05:53:47 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Sat, 19 Apr 2008 13:23:47 +0930
Subject: [sdiy] USB and the art of MIDI
In-Reply-To: <56869.85971.qm@web53301.mail.re2.yahoo.com>
Message-ID: <5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>

Y-ellow Humans.
         I'm wondering if anyone here has tried those little, Cheap, 
Chinese USB to MIDI adaptors? More specifically, has anyone tried using 2 
or more out of a hub at the same time?

Even more specifically, I'm wondering if it might be possible to make an 
ad-hock, expandable, multi-MIDI interface with say 10 or more I/Os. I'm not 
worried about the electrical limitations. IE: Power consumption and so 
fourth. I can take care of that with suitable hacks. All I'm interested in 
is if the computer would see multiple individual MIDI interfaces or get 
thoroughly confused and see them all as just one single MIDI interface. Or 
something in between?

Anyway, If there's anyone out there who has experience with these things 
I'd appreciate at word from the wise.

And just out of interest, the "CYBERMIX" has arrived. Now I just need the 
time to plug it in and see if it works.

Thanks in advance.
Be absolutely Icebox.


  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From Stromeko at nexgo.de  Sat Apr 19 12:58:07 2008
From: Stromeko at nexgo.de (ASSI)
Date: Sat, 19 Apr 2008 12:58:07 +0200
Subject: [sdiy] USB and the art of MIDI
In-Reply-To: <5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>
References: <5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>
Message-ID: <200804191258.07721.Stromeko@nexgo.de>

On Samstag 19 April 2008, Batz Goodfortune wrote:
> Y-ellow Humans.
>          I'm wondering if anyone here has tried those little, Cheap,
> Chinese USB to MIDI adaptors? More specifically, has anyone tried
> using 2 or more out of a hub at the same time?

That should work in principle, but I'd rather use a USB2.0 high-speed 
hub if more than four MIDI interfaces are in use at full bore.

> Even more specifically, I'm wondering if it might be possible to make
> an ad-hock, expandable, multi-MIDI interface with say 10 or more
> I/Os. I'm not worried about the electrical limitations. IE: Power
> consumption and so fourth. I can take care of that with suitable
> hacks. All I'm interested in is if the computer would see multiple
> individual MIDI interfaces or get thoroughly confused and see them
> all as just one single MIDI interface. Or something in between?

Depends on what you mean by "computer".  With a modern Linux I don't see 
any problem, and all interfaces should show up as seperate devices 
(they may have multiple ports).  Getting them to always use the same 
device name and MIDI port number in ALSA will be a bit tricky however, 
normally they will show up in the order they are found during device 
discovery.  MIDI interfaces which need a driver downloaded at each 
plug-in also often require manual configuration, but class-compliant 
interfaces just work.  If the USB descriptors are halfway 
spec-compliant each interface is listed with the name given by the 
manufacturer so it is relatively easy to tell them apart.

WinXP has an arbitrary limit of 10 USB MIDI devices and it counts the 
same device on a different USB port as a seperate device to boot; also 
it will show class compliant interfaces as "USB loudspeaker" with no 
indication as to which interface you're looking at and hideously breaks 
sysex messages that are longer than the send buffer.  USB MIDI does not 
work at all in Win98/SE or earlier (just plugging in such an interface 
will blue-screen the computer instantly) and is probably even buggier 
than WinXP on WinME.  The sysex bug is supposedly fixed in Vista.  
Sysex with interfaces bringing their own drivers is hit-and-miss: if 
they used the Microsoft demo code it won't work, if they actually 
checked the result they may have fixed it.  Sometimes it works and then 
they break it again with a new driver version...

Dunno how the Mac is stacking up in that department, but at least it 
should show the proper device name if the interface provides a suitable 
string descriptor.

> Anyway, If there's anyone out there who has experience with these
> things I'd appreciate at word from the wise.

If timing is important to you, then this setup is probably too 
troublesome all-around.  What may work with one hub may not work with 
another or even when the order of interfaces somehow changes.  With the 
prices I can get here it is still more cost effective to have 4x4 
interfaces directly hanging off the computer's USB ports.  I also find 
the 1x1 "cable interfaces" appealing for their lack of another box to 
have around, but I haven't had a chance to try them yet.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Waldorf MIDI Implementation & additional documentation:
http://Synth.Stromeko.net/Downloads.html#WaldorfDocs



From batzman-nr at all-electric.com  Sat Apr 19 14:06:33 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Sat, 19 Apr 2008 21:36:33 +0930
Subject: [sdiy] USB and the art of MIDI
In-Reply-To: <200804191258.07721.Stromeko@nexgo.de>
References: <5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>
	<5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>
Message-ID: <5.1.0.14.2.20080419203724.03089de8@mail.all-electric.com>

Y-ellow Achim.
         And thanks to all who wrote back on this.

At 12:58 PM 4/19/2008 +0200, ASSI wrote:

>That should work in principle, but I'd rather use a USB2.0 high-speed
>hub if more than four MIDI interfaces are in use at full bore.

Yeah. I should have made that clear I guess. It's all USB2. Although what 
it is to the MIDI converter, I'm not sure. But I'm figuring 400Mb/S to the 
hub at least should cover it.

I was looking at an 8x8 USB matrix but it was a little expensive IMHO. The 
irony being that despite it having 8 I/Os it was still only USB1.

That's still on the table as it were but I liked the modular approach of 
using separate interfaces.

>Depends on what you mean by "computer".  With a modern Linux I don't see
>any problem, and all interfaces should show up as seperate devices
>(they may have multiple ports).  Getting them to always use the same
>device name and MIDI port number in ALSA will be a bit tricky however,
>normally they will show up in the order they are found during device
>discovery.

I have had great difficulty convincing linux how to handle USB devices but 
subsequently I'm pretty sure I could tame that under linux. It should be 
able to discover all devices on the hub in the same order every time. BOSH 
should be able to do that too but you know how M$ products are. They like 
to attack when you're not looking.

All the crap-tops dual boot so it's going to be a matter of figuring out 
which OS is going to give us more mileage. But I know what I'd prefer to 
use. At least under Slackware I know we could go out there and not have the 
things suddenly reboot in the middle of a gig.

>   MIDI interfaces which need a driver downloaded at each
>plug-in also often require manual configuration, but class-compliant
>interfaces just work.  If the USB descriptors are halfway
>spec-compliant each interface is listed with the name given by the
>manufacturer so it is relatively easy to tell them apart.

Well, I'd assume that all these would be the same manufacture. And exactly 
the same type. Although of the 3 I've just bought, 2 are the same and one 
is an orphan. But then again, probably the only difference is the little 
plastic housing they're in. :)

>The sysex bug is supposedly fixed in Vista.

Oh. So that's the only thing that actually works on VISTA now is it?

These crap tops came with vista pre-installed. I kept it on there for about 
3 or 4 weeks. It might be just that I'd been laid up ill for 3 months but I 
haven't laughed that much in the last year. Every time I get a bit down I 
only have to think about running vista. I replaced the hard drive and kept 
the original just in case I ever needed a good belly laugh. It's a good 
thing in a way that Steve Ballmer became a multi-billionaire and only does 
comedy in his spare time. We'd all have died laughing by now.

The MIDI interface limit was always set at 10 from BOSH95 onwards. 
Ironically there was no such limit previously under WIN3.11. This was a big 
problem till one day, under BOSH98SE, we realized we had somehow managed to 
plug in and use 12. But in this case it's all a driver thing. Under USB? 
Who knows?

>Sysex with interfaces bringing their own drivers is hit-and-miss: if
>they used the Microsoft demo code it won't work, if they actually
>checked the result they may have fixed it.  Sometimes it works and then
>they break it again with a new driver version...

Yeah. Been there. Swore I'd never go there again but It'd probably be a 
laugh to stir up the kiddies on the dance floor again. How could I not 
enjoy the site of some pumped up blond blowing chunks into the bass bin 
from too much E and a squeeze of lemon. While her boyfriend looks on 
helpless but later decides to get off with her best friend because at least 
she wasn't wearing her stomach contents when he was dancing with her. Ah. I 
love the nightlife. I love to boogie.

But I digress.

>Dunno how the Mac is stacking up in that department, but at least it
>should show the proper device name if the interface provides a suitable
>string descriptor.

It's BSD. How bad could it be?

>If timing is important to you, then this setup is probably too
>troublesome all-around.  What may work with one hub may not work with
>another or even when the order of interfaces somehow changes.  With the
>prices I can get here it is still more cost effective to have 4x4
>interfaces directly hanging off the computer's USB ports.  I also find
>the 1x1 "cable interfaces" appealing for their lack of another box to
>have around, but I haven't had a chance to try them yet.

In the end we may not need to go out with too many I/Os. I'm getting too 
old to lug. But then again, I know I'll need at least 2, maybe 3 
controllers and at least one out-board instrument per box. Then again, 
we'll be playing to mostly tone deaf bogans who have the rythm of an 
epileptic seizure. They'll probably think a blue screen is the new black.

As those Great Melbournian philosophers TISM once put it.
         "Every band get's the audience they deserve."

Thanks again.
Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From alfred.pear at gmail.com  Sat Apr 19 17:57:12 2008
From: alfred.pear at gmail.com (alfred.pear at gmail.com)
Date: Sat, 19 Apr 2008 11:57:12 -0400
Subject: [sdiy] Solar Power?
Message-ID: <ea992b2f0804190857l1c36df99te0d99ca7e36cf069@mail.gmail.com>

Hi -

I was thinking about making some solar-powered modules - probably just
basic op amps..does anyone have any experience or information about
getting a functional voltage?

-mW


From richard.e.johnson at gmail.com  Sat Apr 19 21:13:34 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Sat, 19 Apr 2008 15:13:34 -0400
Subject: [sdiy] Reproducing Oberhiem "Jump" Voice
Message-ID: <be8b34180804191213w2d5e13dfpb3bb10a8bd44551a@mail.gmail.com>

Dear List,

I'd like your input on reproducing something similar to the Van Halen
"Jump" voice. Some research yields:
It is a "brass" voice was produced using a Oberheim OB-Xa. (Sorry if
this next part is pedantic. I'm new at this.)

Oberheim OB-Xa Specs
   8 voices
   Technology: PWM Synch
   2 OSCs (Waves: pulse saw noise)
   1 Filter: LPF Resonance 2-4 Pole
   1 LFOs: sine, square, sample+hold
   2 ENVs 2x ADSR

My goal is to implement a similar sounding voice with very few
components (some may be digital). I don't have an analog synth to use,
so I've been using software synths. Any help would be appreciated.

Another list member suggested that it looked like a combination of a
Sawtooth Fundamental + a Pulse Wave at 5F or 10F in sync.

I don't think ENV or LFO are too big of a concern right now. The LPF/Q
might be though. I've come up with something close using Sawtooth (F)
and a pulse (2F) on a software emulator.

Can anyone confirm or deny? Also is there some sort of standardized
notation for building analog voices like there is for FM voices or do
analog synths vary too much from one to the next?

Thanks!
Ric

P.S. Sorry to ask for the cliche of all synth sounds. Please no tar,
feathers or Mangus Chord Organs.


From steveecrane at googlemail.com  Sun Apr 20 01:16:44 2008
From: steveecrane at googlemail.com (SEC - GoogleMail)
Date: Sun, 20 Apr 2008 00:16:44 +0100
Subject: [sdiy] Reproducing Oberhiem "Jump" Voice
In-Reply-To: <be8b34180804191213w2d5e13dfpb3bb10a8bd44551a@mail.gmail.com>
References: <be8b34180804191213w2d5e13dfpb3bb10a8bd44551a@mail.gmail.com>
Message-ID: <003301c8a273$70513c90$9900a8c0@JdEToshiba01>

Richard,

If you have Korg's Mono/Poly s/w emulation, I have just the patch for you
...

... I use it live and it's pretty darned close!

Just let me know.


 
Kind regards,
 
Steve Crane.
eMail: SteveECrane at GMail.com
Skype: SteveECrane
 

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Richard Johnson
Sent: 19 April 2008 20:14
To: SDIY
Subject: [sdiy] Reproducing Oberhiem "Jump" Voice

Dear List,

I'd like your input on reproducing something similar to the Van Halen "Jump"
voice. Some research yields:
It is a "brass" voice was produced using a Oberheim OB-Xa. (Sorry if this
next part is pedantic. I'm new at this.)

Oberheim OB-Xa Specs
   8 voices
   Technology: PWM Synch
   2 OSCs (Waves: pulse saw noise)
   1 Filter: LPF Resonance 2-4 Pole
   1 LFOs: sine, square, sample+hold
   2 ENVs 2x ADSR

My goal is to implement a similar sounding voice with very few components
(some may be digital). I don't have an analog synth to use, so I've been
using software synths. Any help would be appreciated.

Another list member suggested that it looked like a combination of a
Sawtooth Fundamental + a Pulse Wave at 5F or 10F in sync.

I don't think ENV or LFO are too big of a concern right now. The LPF/Q might
be though. I've come up with something close using Sawtooth (F) and a pulse
(2F) on a software emulator.

Can anyone confirm or deny? Also is there some sort of standardized notation
for building analog voices like there is for FM voices or do analog synths
vary too much from one to the next?

Thanks!
Ric

P.S. Sorry to ask for the cliche of all synth sounds. Please no tar,
feathers or Mangus Chord Organs.
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From klosmon at sbcglobal.net  Sun Apr 20 03:07:40 2008
From: klosmon at sbcglobal.net (klosmon)
Date: Sat, 19 Apr 2008 18:07:40 -0700
Subject: [sdiy] HS3140 Multiplying DAC
Message-ID: <480A975C.2000805@sbcglobal.net>

It's that time again --
trying to track down a replacement for somebody's OB-8.

I know they're rare, but it doesn't hurt to ask....

~GMM
analogsynthservice.com


From billbigrig at yahoo.com  Sun Apr 20 03:20:39 2008
From: billbigrig at yahoo.com (bill bigrig)
Date: Sat, 19 Apr 2008 18:20:39 -0700 (PDT)
Subject: [sdiy] tda 1022
Message-ID: <817497.51961.qm@web32705.mail.mud.yahoo.com>

Howdy,

 TDA 1022s seem to have gotten scarce all of a sudden.
Anyone have an extra 9 of em laying around for sale?
Thanx
rig


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From xpandrew at ph.k12.in.us  Sun Apr 20 06:01:48 2008
From: xpandrew at ph.k12.in.us (Dump Static)
Date: Sat, 19 Apr 2008 23:01:48 -0500
Subject: [sdiy] Reproducing Oberhiem "Jump" Voice
Message-ID: <480A87ED0200006700017AFA@smithers.ph.k12.in.us>

There is a small amount of portamento used on the original sound.  It's
very noticeable, especially if you play the same patch without the
portamento...

Drew


>>> SEC - GoogleMail <steveecrane at googlemail.com> 04/19/08 18:16 PM >>>
Richard,

If you have Korg's Mono/Poly s/w emulation, I have just the patch for
you
...

... I use it live and it's pretty darned close!

Just let me know.


 
Kind regards,
 
Steve Crane.
eMail: SteveECrane at GMail.com
Skype: SteveECrane
 

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Richard
Johnson
Sent: 19 April 2008 20:14
To: SDIY
Subject: [sdiy] Reproducing Oberhiem "Jump" Voice

Dear List,

I'd like your input on reproducing something similar to the Van Halen
"Jump"
voice. Some research yields:
It is a "brass" voice was produced using a Oberheim OB-Xa. (Sorry if
this
next part is pedantic. I'm new at this.)

Oberheim OB-Xa Specs
   8 voices
   Technology: PWM Synch
   2 OSCs (Waves: pulse saw noise)
   1 Filter: LPF Resonance 2-4 Pole
   1 LFOs: sine, square, sample+hold
   2 ENVs 2x ADSR

My goal is to implement a similar sounding voice with very few
components
(some may be digital). I don't have an analog synth to use, so I've been
using software synths. Any help would be appreciated.

Another list member suggested that it looked like a combination of a
Sawtooth Fundamental + a Pulse Wave at 5F or 10F in sync.

I don't think ENV or LFO are too big of a concern right now. The LPF/Q
might
be though. I've come up with something close using Sawtooth (F) and a
pulse
(2F) on a software emulator.

Can anyone confirm or deny? Also is there some sort of standardized
notation
for building analog voices like there is for FM voices or do analog
synths
vary too much from one to the next?

Thanks!
Ric

P.S. Sorry to ask for the cliche of all synth sounds. Please no tar,
feathers or Mangus Chord Organs.
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Sun Apr 20 06:08:27 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 00:08:27 -0400
Subject: [sdiy] Buchla 194 Fixed Bandpass Filter analysis
In-Reply-To: <m28wzd0zow.fsf@till.com>
References: <3D663AC2-9091-4796-8A29-73AE5CEFCE59@ece.gatech.edu>
	<m28wzd0zow.fsf@till.com>
Message-ID: <AC6DAF8A-0600-45C2-B203-FC443AAC62E8@ece.gatech.edu>

On Apr 17, 2008, at 2:21 AM, Donald Tillman wrote:

>> 1) The highpass S-K has a "feedback resistor" and a "resistor to
>> ground." When I'm considering the "resistor to ground," should I
>> think of the 68K and 100K biasing setup as both being resistors
>> in parallel to "AC ground?" If so, my "to ground" resistor is
>> actually 68K || 100K = 40K.
>
> To AC and DC ground, yeah.  It's called a Thevenin equivalent
> (Wikipedia has an entry for Thevenin's Theorem).  A resistor divider
> between two voltage sources such as the power rails is equivalent to a
> single resistor, of value equal to the parallel combination of the
> two, wired to a single voltage in between.

I'm down with Thevenin. I just always get weirded out when I see a  
transistor. ;)

>> 2) All of the bases of the voltage buffers, except for the first one,
>> have 10K resistors going into the bases. Why are those 10K resistors
>> there?
>
> Discrete emitter followers often include base resistors to hold down
> high frequency oscillations.  Similar to the dominant pole in opamp
> circuits.

Thanks!

>> 3) There's a 2K2 and 100K voltage divider right at the beginning
>> that attenuates the signal by a factor of 50, presumably to get
>> the signal into the "linear small signal analysis"
>> range. But... I don't see anywhere where the gain is brought back
>> up at the end! Is there something I'm missing?
>
> The resistor values are actually the other way around; the circuit
> only attenutates the input signal by 1/50th.  The 100K resistor keeps
> the input cap from floating and prevents loud pops when you connect a
> ground-centered input, and the 2.2K protects the transistor from nasty
> hight current transients.

Bah, I'm an idiot... I've been looking at so many OTA circuits that I  
flipped that around in my head!

- Aaron




From lanterma at ece.gatech.edu  Sun Apr 20 07:18:34 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 01:18:34 -0400
Subject: [sdiy] Roland JP-4 VCO
In-Reply-To: <001501c89e7c$39a7f120$85db47d1@ca>
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net><006f01c89de5$3e52e230$8501a8c0@ice9><6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net><000701c89e69$cfa96900$dedb47d1@ca>
	<7FDD4E14-1A50-4502-AA89-5BEA23D4C413@ece.gatech.edu>
	<001501c89e7c$39a7f120$85db47d1@ca>
Message-ID: <55CC0522-DC19-4D54-9D59-95C983305E87@ece.gatech.edu>


On Apr 14, 2008, at 6:09 PM, Mike I wrote:

> Hi - the Roland JP-4 VCO is a bits + pieces charge-balancing circuit  
> mostly
> built with standard CMOS and transistors ( no RC4151 converter as in  
> the
> Chroma). JP-4 has a reputation for going out of tune easily though,  
> maybe
> out of tune but with nice linearity.

I am curious about this - anyone know of JP-4 schematics on the web?  
(Quick googling didn't uncover any)

- Aaron


From xyzzy at sysabend.org  Sun Apr 20 07:41:56 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Sat, 19 Apr 2008 22:41:56 -0700
Subject: [sdiy] tda 1022
In-Reply-To: <817497.51961.qm@web32705.mail.mud.yahoo.com>
References: <817497.51961.qm@web32705.mail.mud.yahoo.com>
Message-ID: <20080420054156.GC59657@moo.sysabend.org>

On Sat, Apr 19, 2008 at 06:20:39PM -0700, bill bigrig wrote:
>  TDA 1022s seem to have gotten scarce all of a sudden.
> Anyone have an extra 9 of em laying around for sale?

I have quite a few left if anyone needs some.  $6ea.  Contact me off list.

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From sounddoctorin at imt.net  Sun Apr 20 08:30:36 2008
From: sounddoctorin at imt.net (Bob Weigel)
Date: Sun, 20 Apr 2008 00:30:36 -0600
Subject: [sdiy] Roland JP-4 VCO
In-Reply-To: <55CC0522-DC19-4D54-9D59-95C983305E87@ece.gatech.edu>
References: <6.2.1.2.2.20080413212802.021a60e8@mail.comcast.net><006f01c89de5$3e52e230$8501a8c0@ice9><6.2.1.2.2.20080414064212.020f19f0@mail.comcast.net><000701c89e69$cfa96900$dedb47d1@ca>	<7FDD4E14-1A50-4502-AA89-5BEA23D4C413@ece.gatech.edu>	<001501c89e7c$39a7f120$85db47d1@ca>
	<55CC0522-DC19-4D54-9D59-95C983305E87@ece.gatech.edu>
Message-ID: <480AE30C.2050005@imt.net>

Aaron, the sounddoctorin.com page is more concise than google in general 
for looking for schematics at least.  At least I try to keep it that 
way. In terms of schematics, the google 'turnover' rate isn't real 
high.  If anything is obsolete on my site always let me know so that I 
can keep it updated, but 
http://sounddoctorin.com/synthtec/roland/jp4.htm has the fdisk archive 
listed for a source for jp4.  HOPEFULLY EVERY resource availabe on 
google is concisely pointed to in an orderly fashion on that site.  Let 
me know if not. -Bob

Aaron Lanterman wrote:

>
> On Apr 14, 2008, at 6:09 PM, Mike I wrote:
>
>> Hi - the Roland JP-4 VCO is a bits + pieces charge-balancing circuit  
>> mostly
>> built with standard CMOS and transistors ( no RC4151 converter as in  
>> the
>> Chroma). JP-4 has a reputation for going out of tune easily though,  
>> maybe
>> out of tune but with nice linearity.
>
>
> I am curious about this - anyone know of JP-4 schematics on the web?  
> (Quick googling didn't uncover any)
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>


From lanterma at ece.gatech.edu  Sun Apr 20 08:55:07 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 02:55:07 -0400
Subject: [sdiy] Matching across matched pairs for dual VCOs
Message-ID: <77B05B74-2B07-4530-B17B-D735F0AEA959@ece.gatech.edu>

Suppose you were building two VCOs that you wanted to be able to track  
one another pretty well, say for yummy FM goodness.

Would there be an advantage to using, say, something like a THAT chip  
that has _four_ matched NPNs, so that your two expo converters would  
be matched with each other and also stay at the same temp?

Or would other sources of error between the circuits swamp such  
effects and make it not worth bothering with?

- Aaron


From lanterma at ece.gatech.edu  Sun Apr 20 09:05:32 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 03:05:32 -0400
Subject: [sdiy] Matching transistors in "diode ladder" filters
Message-ID: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>

One of my students is working on building a variant of the Roland 100  
VCF:

http://fa.utfs.org/diy/roland100/101_op27.jpg

See lower half, 3rd "block" from the left.

I've heard that in the Moog ladder, it's important to match the top  
transistors and the bottom transistors, but the ones in the middle  
aren't so important to match (and some schematics of various Moogs  
bears this out.)

Does anyone have advice of what is important to match in a "diode  
ladder" filter? We're doing the Roland 100, but I the same question  
could apply to TB-303, EMS, and Sonic V (IIRC).

I told my student to use CA3046s to get some cheap pairs (since I have  
a bunch), but if he could use garden variety diodes for some that  
would be convenient.

- Aaron


From yves.usson at imag.fr  Sun Apr 20 09:38:46 2008
From: yves.usson at imag.fr (yves usson)
Date: Sun, 20 Apr 2008 09:38:46 +0200
Subject: [sdiy] Matching transistors in "diode ladder" filters
In-Reply-To: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>
References: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>
Message-ID: <480AF306.7090200@imag.fr>

Hi Aaron

In my recreation of the EMS diode ladder filter I used simple 1N4148 and 
I selected
within the same batch those which forward drop voltages were similar 
within a range
of 3mV. If you take diodes from the same batch you will see that the 
tolerance is quite
good indeed and in order to have 7 matched pair you need not to test 
more than 20 diodes.

http://yusynth.net/Modular/EN/EMSVCF

Cheers

Yves Ussson
http://yusynth.net



Aaron Lanterman a ?crit :
> One of my students is working on building a variant of the Roland 100 VCF:
> 
> http://fa.utfs.org/diy/roland100/101_op27.jpg
> 
> See lower half, 3rd "block" from the left.
> 
> I've heard that in the Moog ladder, it's important to match the top 
> transistors and the bottom transistors, but the ones in the middle 
> aren't so important to match (and some schematics of various Moogs bears 
> this out.)
> 
> Does anyone have advice of what is important to match in a "diode 
> ladder" filter? We're doing the Roland 100, but I the same question 
> could apply to TB-303, EMS, and Sonic V (IIRC).
> 
> I told my student to use CA3046s to get some cheap pairs (since I have a 
> bunch), but if he could use garden variety diodes for some that would be 
> convenient.
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From Stromeko at nexgo.de  Sun Apr 20 11:53:45 2008
From: Stromeko at nexgo.de (ASSI)
Date: Sun, 20 Apr 2008 11:53:45 +0200
Subject: [sdiy] Matching transistors in "diode ladder" filters
In-Reply-To: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>
References: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>
Message-ID: <200804201153.45395.Stromeko@nexgo.de>

On Sonntag 20 April 2008, Aaron Lanterman wrote:
> I told my student to use CA3046s to get some cheap pairs (since I
> have a bunch), but if he could use garden variety diodes for some
> that would be convenient.

If you make the diodes out of monolithic transistor arrays anyway, I 
would short collector and base and not leave the collector open as the 
S100 schematics show.  This should give a much better log conformance 
over more decades of current and the requisite hfe matching should be 
guaranteed.  The dynamic resistance is different and will probably 
require to change the capacitors a bit.  Using garden variety diodes 
should work in principle, but the linearity would often be quite a bit 
worse than a BE diode from a transistor, signal diodes with not too 
high breakdown voltage should be best.  There are some dual diode 
arrays in series connection (meant for input protection) that should 
help to cut down on the number of packages (I think there is a TI quad 
array with eight seperate leads, but with Schottky diodes IIRC).


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Waldorf MIDI Implementation & additional documentation:
http://Synth.Stromeko.net/Downloads.html#WaldorfDocs


From jhaible at debitel.net  Sun Apr 20 11:54:45 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 20 Apr 2008 11:54:45 +0200
Subject: [sdiy] tda 1022
References: <817497.51961.qm@web32705.mail.mud.yahoo.com>
Message-ID: <000501c8a2cc$921ef6b0$0400a8c0@jhsilent>

>  TDA 1022s seem to have gotten scarce all of a sudden.

Mea Culpa !

JH.


From jhaible at debitel.net  Sun Apr 20 12:12:19 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 20 Apr 2008 12:12:19 +0200
Subject: [sdiy] Matching across matched pairs for dual VCOs
References: <77B05B74-2B07-4530-B17B-D735F0AEA959@ece.gatech.edu>
Message-ID: <002101c8a2cf$057346f0$0400a8c0@jhsilent>


>Suppose you were building two VCOs that you wanted to be able to track
>one another pretty well, say for yummy FM goodness.
>
>Would there be an advantage to using, say, something like a THAT chip
>that has _four_ matched NPNs, so that your two expo converters would
>be matched with each other and also stay at the same temp?

I don't expect any advantage. Offset is an issue within each pair - the 
absolute Vbe at a certain current is not.
So you don't need to match any "offset" between pair 1 and pair 2.

As for tracking, you have to trim this anyway, because of resistor 
tolerances.

If you share a Quad array for two VCOs, you risk interlocking.
I don't say you *will* get such problems, but you surely have another 
potential problem to take care to avoid.

JH.



From jhaible at debitel.net  Sun Apr 20 12:17:23 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 20 Apr 2008 12:17:23 +0200
Subject: [sdiy] Matching transistors in "diode ladder" filters
References: <6F4B0FB3-F038-4BE6-BAD7-4E735713EB09@ece.gatech.edu>
	<480AF306.7090200@imag.fr>
Message-ID: <002501c8a2cf$bad80b70$0400a8c0@jhsilent>

The EMS VCF has a DC negative feedback path (independent of the resonance 
setting!), which helps to "center" your bias point even without tightly 
matched components. I haven't tried it, but I wouldn't be surprsed if it'd 
also work with completely unmatched parts.

JH.


----- Original Message ----- 
From: "yves usson" <yves.usson at imag.fr>
To: "Aaron Lanterman" <lanterma at ece.gatech.edu>; "synth- >> synth diy" 
<synth-diy at dropmix.xs4all.nl>
Sent: Sunday, April 20, 2008 9:38 AM
Subject: Re: [sdiy] Matching transistors in "diode ladder" filters


Hi Aaron

In my recreation of the EMS diode ladder filter I used simple 1N4148 and
I selected
within the same batch those which forward drop voltages were similar
within a range
of 3mV. If you take diodes from the same batch you will see that the
tolerance is quite
good indeed and in order to have 7 matched pair you need not to test
more than 20 diodes.

http://yusynth.net/Modular/EN/EMSVCF

Cheers

Yves Ussson
http://yusynth.net



Aaron Lanterman a ?crit :
> One of my students is working on building a variant of the Roland 100 VCF:
>
> http://fa.utfs.org/diy/roland100/101_op27.jpg
>
> See lower half, 3rd "block" from the left.
>
> I've heard that in the Moog ladder, it's important to match the top
> transistors and the bottom transistors, but the ones in the middle
> aren't so important to match (and some schematics of various Moogs bears
> this out.)
>
> Does anyone have advice of what is important to match in a "diode
> ladder" filter? We're doing the Roland 100, but I the same question
> could apply to TB-303, EMS, and Sonic V (IIRC).
>
> I told my student to use CA3046s to get some cheap pairs (since I have a
> bunch), but if he could use garden variety diodes for some that would be
> convenient.
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From mr at analogue.org  Sun Apr 20 13:22:04 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Sun, 20 Apr 2008 13:22:04 +0200
Subject: [sdiy] Bourns 51/53 potentiometer opinions?
Message-ID: <200804201121.m3KBLR6i010180@dropmix.xs4all.nl>

Anyone with experience of Bourns 51/53 series pots?

With their metal shaft/bushing they seem like a more high-quality pot 
than Bourns 91-99 series, a bit more like Spectrol 148/149 series 
perhaps. Or even better?

Thanks,

/mr




From keithw at cix.compulink.co.uk  Sun Apr 20 14:25:00 2008
From: keithw at cix.compulink.co.uk (Keith Winstanley)
Date: Sun, 20 Apr 2008 13:25 +0100 (BST)
Subject: [sdiy] Spoilt for choice
Message-ID: <memo.933046@cix.compulink.co.uk>

Two tested and working superbly, the discrete one just finished,
no time to test - off to Wales for a week!


http://homepage.ntlworld.com/helenemorey/P4200015.JPG

Keith

http://home.freeuk.net/lowpass



From neil.johnson97 at ntlworld.com  Sun Apr 20 16:27:03 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Sun, 20 Apr 2008 15:27:03 +0100
Subject: [sdiy] Bourns 51/53 potentiometer opinions?
In-Reply-To: <200804201121.m3KBLR6i010180@dropmix.xs4all.nl>
References: <200804201121.m3KBLR6i010180@dropmix.xs4all.nl>
Message-ID: <EDE60CBA-6DCE-41A3-8C13-DEADD1376BC9@ntlworld.com>

Hi,

Mattias Rickardsson wrote:
> Anyone with experience of Bourns 51/53 series pots?
>
> With their metal shaft/bushing they seem like a more high-quality  
> pot than Bourns 91-99 series, a bit more like Spectrol 148/149  
> series perhaps. Or even better?

Yes - _very_ nice pots.  I bought three trays of 10k linear cermet  
pots with integrated PCB support bracket on eBay a few years back.   
Including airmail from the US they worked out at 30c each.  Very  
impressed with the quality.

Neil
--
http://www.njohnson.co.uk





From pschreiber at sbcglobal.net  Sun Apr 20 16:53:05 2008
From: pschreiber at sbcglobal.net (Paul Schreiber)
Date: Sun, 20 Apr 2008 09:53:05 -0500
Subject: [sdiy] Spoilt for choice
References: <memo.933046@cix.compulink.co.uk>
Message-ID: <006301c8a2f6$3db1dbe0$b000a8c0@curley>

> Two tested and working superbly, the discrete one just finished,
> no time to test - off to Wales for a week!
> 
> 
> http://homepage.ntlworld.com/helenemorey/P4200015.JPG
> 

Yikes! The return of the DonneyMoog! :)

Paul S.



From keithw at cix.compulink.co.uk  Sun Apr 20 18:01:00 2008
From: keithw at cix.compulink.co.uk (Keith Winstanley)
Date: Sun, 20 Apr 2008 17:01 +0100 (BST)
Subject: [sdiy] Spoilt for choice
Message-ID: <memo.935429@cix.compulink.co.uk>

In-Reply-To: <006301c8a2f6$3db1dbe0$b000a8c0 at curley>

> Yikes! The return of the DonneyMoog! :)
> 
> Paul S.
> 


Sharp eyes! built by me though
:o)



Keith

http://home.freeuk.net/lowpass



From wonggster at gmail.com  Sun Apr 20 20:29:50 2008
From: wonggster at gmail.com (gino wong)
Date: Sun, 20 Apr 2008 14:29:50 -0400
Subject: [sdiy] tda 1022
In-Reply-To: <20080420054156.GC59657@moo.sysabend.org>
References: <817497.51961.qm@web32705.mail.mud.yahoo.com>
	<20080420054156.GC59657@moo.sysabend.org>
Message-ID: <18ef0b50804201129meb55a7aye7e9a0f6d1047106@mail.gmail.com>

I need 3 too rig.  If you run int a price break at 10 get to me

gino

On 4/20/08, Tom Arnold <xyzzy at sysabend.org> wrote:
> On Sat, Apr 19, 2008 at 06:20:39PM -0700, bill bigrig wrote:
>  >  TDA 1022s seem to have gotten scarce all of a sudden.
>  > Anyone have an extra 9 of em laying around for sale?
>
>
> I have quite a few left if anyone needs some.  $6ea.  Contact me off list.
>
>
>  --
>   -----------------------------------------------------------------
>   - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org
>   - SynthGeek        -
>   - BBD Fanatic      -  "...is it a virus, a drug, or a religion?"
>   - echo evho wjxo   -    Juanita Shrugs. "What's the difference?"
>   --------------------
>
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


-- 
Wanted:
Odd rare unusual and maligned electronic devices such as: Davolisynt,
Kawai, Teisco synthesizers, other rarely remembered items

??
Gino Wong
Engineer, Studio Supervisor
LBPH
(800) 222-1754


From billbigrig at yahoo.com  Sun Apr 20 21:59:25 2008
From: billbigrig at yahoo.com (bill bigrig)
Date: Sun, 20 Apr 2008 12:59:25 -0700 (PDT)
Subject: [sdiy] USB,MIDI,SCSI
Message-ID: <4894.95852.qm@web32706.mail.mud.yahoo.com>

G'day,

 What is out there that will allow scsi and usb to
play nice together. My gear is old, but a little bit
of it is new. Is it possible to convert USB drives to
a SCSI system?  Stuff like that. Thanx
rig


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From dalenkarl at yahoo.se  Sun Apr 20 22:17:02 2008
From: dalenkarl at yahoo.se (karl dalen)
Date: Sun, 20 Apr 2008 22:17:02 +0200 (CEST)
Subject: SV: Re: [sdiy] Any LM331 experts around?
In-Reply-To: <7FDD4E14-1A50-4502-AA89-5BEA23D4C413@ece.gatech.edu>
Message-ID: <523328.46556.qm@web27601.mail.ukl.yahoo.com>

There are a thick appnote paper from Linear Tech with designs
and theory around charge balanced oscillators. Available from
their site. It's a nice complementary to the Chroma service 
manual to understand and setup lab tests for your students. 

KD
--- Aaron Lanterman <lanterma at ece.gatech.edu> skrev:

> 
> On Apr 14, 2008, at 3:57 PM, Mike I wrote:
> 
> > Maybe contact Bob Pease at Nat Semi - he designed it.
> >
> > VCO in Roland Jupiter-4 ( JP-4 ) also a charge-balancing design with  
> > uA726
> > in front with digital range and waveform selection.
> 
> Is this related to the "charge pump" in the Rhodes Chroma VCO? (I was  
> thinking that might also make a good student project)
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



	
	
		
_________________________________________________________
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From blincoln at eventualdecline.com  Sun Apr 20 22:32:28 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Sun, 20 Apr 2008 13:32:28 -0700
Subject: [sdiy] USB,MIDI,SCSI
In-Reply-To: <4894.95852.qm@web32706.mail.mud.yahoo.com>
References: <4894.95852.qm@web32706.mail.mud.yahoo.com>
Message-ID: <480BA85C.5040800@eventualdecline.com>

Can you be more specific about what you'd like to accomplish? I ask 
because depending on the specifics, it may be easier if you take a 
slightly different approach. For example, if you were wanting to replace 
the hard drive in an Emax, I'd recommend taking a page from the Xbox 
hackers and rather than USB, looking into installing a SCSI <-> Compact 
Flash adapter and storing everything on a CF card.

Whether it needs to be easily portable and/or quick to reconfigure is 
also a factor. For example, if you needed to use a hard drive and could 
find one that would work in both a SCSI and a USB external enclosure, 
you could just swap it between them as needed, but that would be kind of 
a hassle to do frequently.

bill bigrig wrote:
> G'day,
>
>  What is out there that will allow scsi and usb to
> play nice together. My gear is old, but a little bit
> of it is new. Is it possible to convert USB drives to
> a SCSI system?  Stuff like that. Thanx
> rig
>   


From jhaible at debitel.net  Sun Apr 20 23:43:38 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 20 Apr 2008 23:43:38 +0200
Subject: [sdiy] Interpolating Scanner and Hammond Scanner Vibrato PCB
	interest?
Message-ID: <025c01c8a32f$989c0010$0400a8c0@jhsilent>

Hi,

Here's an idea how I could possibly resurrect my Scanner Vibrato project.

Instead of taking another go on a dedicated chorus / vibrato module, I could 
offer a full-fledged Interpolating Scanner with 9 stages, with an option to 
have the inductors on the PCB to turn it into a Hammond Chorus/Vibrato.

That way, the PCB can be used by both, Modular Synth users, and those who 
are looking for a good Hammond Vibrato emulation.

My original Interpolating Scanner is described here (8-stage version):
http://jhaible.heim.at/tonline_stuff/jh_ipscan.html

and the Hammond Vibrato Emulation is here:
http://jhaible.heim.at/scanner_vibrato/jh_scanner_vibrato.html

So the idea is to combine the two projects, hoping there will be enough 
demand for such a PCB to make it a project to be in the black, commercially.

The new version would have 9 stages of linear scanning (to fully cover the 
16 positions of the mechanical rotary Hammond scanner). The scan can be 
performed by *any* modulation source (LFO, envelopes, audio rate, you name 
it) - not just with a LFO as in my earlier scanner vibrato.
All the audio waveshaping capabilities of the Interpolating Scanner would be 
preseved, as well. (Piecewise linear interpolation of fixed, or modulated, 
breakpoints).

The pcb would also include the footprint for 25 inexpensive inductors, plus 
the buffer stages for makeup gain (required with cheap inductors; unlike the 
original Hammond Line Box)

All the interconnections between this inductor delay line and the Scanner 
part would be done mechanically, with switches, just like the real Hammond. 
(No more CMOS switch matrix.)
This also allows to use the board for a generic interpolating scanner with a 
jack for each stage's audio or CV input - with these inputs normalized to 
the Inductor delay line's taps.

No more SSM chips in the new version, either. VCAs will all be discrete, 
built from transistor pairs. (9 transistor pairs like LM394 or similar 
required)

Would this be an interesting project?

JH.



From xyzzy at sysabend.org  Mon Apr 21 00:21:26 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Sun, 20 Apr 2008 15:21:26 -0700
Subject: [sdiy] LF357 Metal can
Message-ID: <20080420222126.GI59657@moo.sysabend.org>

By any chance does anyone have or know of a source for Metal can LF357s?   I
thought I had some left but I only seem to have them in DIP and for this
particular application ( rebuilding an old preamp ) I'd like to go with a
metal can for it.

I suppose in this application there are a ton of good substitutes like
perhaps the OPA134 also in DIP so maybe I just shouldnt stress about it but I
also havent popped the lid yet to see if the board was arranged for DIP or
circular pinout.  Yeah, this might ring a bell for any Dynaco fans out
there...

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From batzman-nr at all-electric.com  Mon Apr 21 02:01:34 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Mon, 21 Apr 2008 09:31:34 +0930
Subject: [sdiy] USB,MIDI,SCSI
In-Reply-To: <480BA85C.5040800@eventualdecline.com>
References: <4894.95852.qm@web32706.mail.mud.yahoo.com>
	<4894.95852.qm@web32706.mail.mud.yahoo.com>
Message-ID: <5.1.0.14.2.20080421091647.03093bf8@mail.all-electric.com>

Y-ellow Ben 'n' all.

At 01:32 PM 4/20/2008 -0700, Ben Lincoln wrote:
>Can you be more specific about what you'd like to accomplish? I ask
>because depending on the specifics, it may be easier if you take a
>slightly different approach. For example, if you were wanting to replace
>the hard drive in an Emax, I'd recommend taking a page from the Xbox
>hackers and rather than USB, looking into installing a SCSI <-> Compact
>Flash adapter and storing everything on a CF card.

Ben, You're a frigging genius. I never thought of that. I don't have any 
issues with HDs but I've got a Yam sampler. It has both SCSI and IDE. I've 
even got a bunch of adaptors right here.

Mind you, if I want to talk to it, I still have to deal with SCSI so an 
adaptor that allows the crap-tops to talk to a SCSI device would be good. 
Better hit EvilBAbY I guess.

Just for succinctness. Under Linnoox, it would be fairly easy to redefine 
what software talks to what device. Almost everything that ISN'T an IDE 
device is some warped version of a SCSI device anyway.

There are USB/Centronix adaptors out there. I've used a few. I want to get 
round to seeing if I can fool this "skidMARK of the Unicorn" MIDI box to 
talk over one. Since it talks to a printer port. But USB/SCSI? "Mmmm Tricky."

But tip-o-the-hat to both of you.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From ijfritz at comcast.net  Mon Apr 21 02:08:58 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Sun, 20 Apr 2008 18:08:58 -0600
Subject: [sdiy] Any LM331 experts around?
Message-ID: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>

Mystery revealed.

I built the high-speed version *without* the  2N2222 circuit.  It had a 
pretty severe T drift, about -400 ppm/K.  More than 10x the 
spec.  Apparently the spec is only for the 10 kHz application.  The 2N2222 
circuit is for temperature compensation -- it puts extra current into the 
timing cap as T increases.  So, technically, I guess it's a modification 
for high freq operation, as they say, but really it's a tempco 
correction.  I got the final drift to under 10 ppm/K.

Tracking of the full VCO (including the expo converter) is within 0.05% 
over 11 octaves. The currents at the low end are very small, since the max 
current is 0.1 mA.   Probably the low end could be fixed with a small 
amount of offset trim.

This is easily my best VCO ever.  What a fabulous chip!

   Ian

---------------------------------------------
I'm looking at the LM331 data sheet and can't figure out what the 
transistor in Fig. 4 is for.  They just say that Fig. 3 has been modified 
for high freq operation.  Any expertise or ideas?  



From lanterma at ece.gatech.edu  Mon Apr 21 03:50:08 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 21:50:08 -0400
Subject: [sdiy] Other dedicated V-to-freq chips
In-Reply-To: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>
References: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>
Message-ID: <BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>

Ian's recent experiences with the LM331 made me wonder if some other  
dedicated V-to-freq chips were worthy of exploration?

I have datasheets for the following on my http://users.ece.gatech.edu/~lanterma/sdiy/datasheets 
  page:

? Analog Devices AD537 ($13.74/1 Digi-Key) (may be overkill for synth  
work)
? Analog Devices AD654
? Analog Devices ADVCF32
? National Semiconductor LM231/LM331 ($6.38/1 LM231, $2.8/1 LM331 Digi- 
Key)
? Fairchild KA331
? Exar XR2206 ($3.59/1 Jameco)
? Exar XR2209, Radio Shack Ap Note
? Exar XR4151 (used in the Rhodes Chroma!) ($1.29/1 Jameco)
? Microchip TC9400/9401/9402 ($6.881/1 TC9400, $7.01/60 TC9401,  
$3.25/1 TC9402 Digi-Key)

The XR4151 is the only I know of to turn up in a commercial synth.

Some of the above chips appear in posts in the SDIY archives, but the  
reports tend not to be highly enthusiastic - but most of them have  
probably not been subject to the Fritz treatment. I think Ian could  
make an in-tune-for-10-octaves zero-heat-drift VCO out of a rubber  
band, a box of legos, and a caffinated ferret.

- Aaron


From ijfritz at comcast.net  Mon Apr 21 04:04:54 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Sun, 20 Apr 2008 20:04:54 -0600
Subject: [sdiy] Other dedicated V-to-freq chips
In-Reply-To: <BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>
References: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>
	<BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>
Message-ID: <6.2.1.2.2.20080420200359.020e7588@mail.comcast.net>

At 07:50 PM 4/20/2008, Aaron Lanterman wrote:
>I think Ian could
>make an in-tune-for-10-octaves zero-heat-drift VCO out of a rubber
>band, a box of legos, and a caffinated ferret.

Why not? As long as the ferret has perfect pitch ...

:-)

Ian



From magnus at rubidium.dyndns.org  Mon Apr 21 04:06:41 2008
From: magnus at rubidium.dyndns.org (Magnus Danielson)
Date: Mon, 21 Apr 2008 04:06:41 +0200 (CEST)
Subject: [sdiy] Other dedicated V-to-freq chips
In-Reply-To: <BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>
References: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>
	<BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>
Message-ID: <20080421.040641.415917433278918159.cfmd@bredband.net>

From: Aaron Lanterman <lanterma at ece.gatech.edu>
Subject: [sdiy] Other dedicated V-to-freq chips
Date: Sun, 20 Apr 2008 21:50:08 -0400
Message-ID: <BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D at ece.gatech.edu>

> Ian's recent experiences with the LM331 made me wonder if some other dedicated V-to-freq chips were worthy of exploration?
> 
> I have datasheets for the following on my http://users.ece.gatech.edu/~lanterma/sdiy/datasheetspage:
> 
> ? Analog Devices AD537 ($13.74/1 Digi-Key) (may be overkill for synth work)
> ? Analog Devices AD654
> ? Analog Devices ADVCF32
> ? National Semiconductor LM231/LM331 ($6.38/1 LM231, $2.8/1 LM331 Digi-Key)
> ? Fairchild KA331
> ? Exar XR2206 ($3.59/1 Jameco)
> ? Exar XR2209, Radio Shack Ap Note
> ? Exar XR4151 (used in the Rhodes Chroma!) ($1.29/1 Jameco)
> ? Microchip TC9400/9401/9402 ($6.881/1 TC9400, $7.01/60 TC9401, $3.25/1 TC9402 Digi-Key)
> 
> The XR4151 is the only I know of to turn up in a commercial synth.
> 
> Some of the above chips appear in posts in the SDIY archives, but the reports tend not to be highly enthusiastic - but most of them have probably not been subject to the Fritz treatment. I think Ian could make an in-tune-for-10-octaves zero-heat-drift VCO out of a rubber band, a box of legos, and a caffinated ferret.

Hold the ferret, strong on the mayo please!

I just recalled that the Elka Synthex uses a pair of high frequency V-Fs which
is divided down in a organ style. The waveshaping is done using counter tricks
while modulation is done on the HF generators. The benefit is low need to trim.
Too lazy to dig up the schematics, but I could do that if needed.

Cheers,
Magnus


From marxspeakstruth at gmail.com  Mon Apr 21 04:37:57 2008
From: marxspeakstruth at gmail.com (Spencer Johnson)
Date: Sun, 20 Apr 2008 21:37:57 -0500
Subject: [sdiy] Entirely OT: Tuscaloosa, AL
Message-ID: <89278f010804201937y164c399w5a821b4678812250@mail.gmail.com>

Is anyone on list from Tuscaloosa, Alabama? I'm moving there soon, and
I have some questions about the local audio scene, etc. Sorry for the
OT post.

Thanks,
Spencer


From lanterma at ece.gatech.edu  Mon Apr 21 04:53:55 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 22:53:55 -0400
Subject: [sdiy] Elka Synthex VCO (was: Other dedicated V-to-freq chips)
In-Reply-To: <20080421.040641.415917433278918159.cfmd@bredband.net>
References: <6.2.1.2.2.20080420175324.020d8d30@mail.comcast.net>
	<BC5F194E-A121-4F0D-A630-BDB5D0D7DB4D@ece.gatech.edu>
	<20080421.040641.415917433278918159.cfmd@bredband.net>
Message-ID: <E8503454-7F1A-4E10-BE5E-C4FDB6CC33D7@ece.gatech.edu>

On Apr 20, 2008, at 10:06 PM, Magnus Danielson wrote:

> I just recalled that the Elka Synthex uses a pair of high frequency  
> V-Fs which
> is divided down in a organ style. The waveshaping is done using  
> counter tricks
> while modulation is done on the HF generators. The benefit is low  
> need to trim.
> Too lazy to dig up the schematics, but I could do that if needed.

Sound doctorin' website comes through:

http://manuals.fdiskc.com/flat/Elka%20Synthex%20Schematic.pdf

See board 410CST5840, there's LF331s all over it.

Goodness gracious that is one monster of a synth. There is an insane  
amount of digital logic chips in it.

- Aaron


From lanterma at ece.gatech.edu  Mon Apr 21 05:31:00 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 23:31:00 -0400
Subject: [sdiy] Elka Synthex VCA/VCF is extremely interesting
Message-ID: <AFFBF30C-C339-4373-A2AD-6711110F9B33@ece.gatech.edu>

Check out the 410CST5800 schematic, right column - that's where the  
VCA and VCF live:

http://manuals.fdiskc.com/flat/Elka%20Synthex%20Schematic.pdf

The schematic takes a bit of practice to read.

Each VCA consists of two OTAs - the output of one drives the input of  
the other! It looks like one of the OTAs is a VCA whose job is to  
modulate the CV modulating the audio, at least if I'm reading it  
right. The OTAs are 13600s, 4Q and 8Q on the schematic.

The filters consist of two CEM3320s, 2Q and 6Q. Find them is tricky  
since their bits and pieces are spread all over the schematic. It's  
hooked up with electronic switches all over the place.

The CEM3320 consists of OTA-buffer pairs, with a tap point between the  
OTA and the buffer for you to hang a cap (or whatever) off of, so in  
theory you could recreate this with LM13700s or something, if you  
added your own expo converters.

The last two OTAs in the chain appear set up as straight single-pole  
LPFs.

The first two look tike a typical single-pole OTA-C LPF, except each  
has a connection from the input to where the cap normally hits ground,  
and there's a switch that you can use to switch that ground connection  
in and out. Similarly, where you normally see the input of a LPF, you  
see a switch. So I'm guessing that these are used alternately - i.e.  
one is on, and one is off, and you can use this to switch between a  
highpass and lowpass LPFs.

It appears that the output of a four-pole block can be tapped from the  
output of the last pole, the output of the last pole with different  
amounts of gain  (based on resistors I see), or from output of the  
second pole. Whatever the output is is fed back to the resonance input  
pin of the 3320 (pin 8), which internally in the chip is fed back to  
the negative input of the first OTA.

How interesting - I haven't seen anything quite exactly like this!

I'm procrastinating... I'm supposed to be writing up solutions to a  
homework assignment. ;)

- Aaron, blessing his parents who are here to help take care of the  
new little one (and his mother-in-law who has helped the past two  
week, and who is now heading home)


From lanterma at ece.gatech.edu  Mon Apr 21 05:37:00 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 20 Apr 2008 23:37:00 -0400
Subject: [sdiy] Elka Synthex VCA/VCF is extremely interesting
In-Reply-To: <AFFBF30C-C339-4373-A2AD-6711110F9B33@ece.gatech.edu>
References: <AFFBF30C-C339-4373-A2AD-6711110F9B33@ece.gatech.edu>
Message-ID: <12F47A6B-808F-481D-AD29-F1B0C507B958@ece.gatech.edu>


On Apr 20, 2008, at 11:31 PM, Aaron Lanterman wrote:

> that these are used alternately - i.e. one is on, and one is off,  
> and you can use this to switch between a highpass and lowpass LPFs.

Doh. I mean highpass and lowpass VCFs.

- Aaron


From dlmanley at sonic.net  Mon Apr 21 07:38:40 2008
From: dlmanley at sonic.net (Dave Manley)
Date: Sun, 20 Apr 2008 22:38:40 -0700
Subject: SV: Re: [sdiy] Any LM331 experts around?
In-Reply-To: <523328.46556.qm@web27601.mail.ukl.yahoo.com>
References: <523328.46556.qm@web27601.mail.ukl.yahoo.com>
Message-ID: <480C2860.1000300@sonic.net>

karl dalen wrote:
> There are a thick appnote paper from Linear Tech with designs
> and theory around charge balanced oscillators. Available from
> their site. It's a nice complementary to the Chroma service 
> manual to understand and setup lab tests for your students. 
>
> KD
>   
Hi Karl,

Do you have an app note number (ANxxxx) or a lnk?

Thanks,
Dave


From alvitar at xavax.com  Mon Apr 21 07:49:42 2008
From: alvitar at xavax.com (Phillip Harbison)
Date: Mon, 21 Apr 2008 00:49:42 -0500
Subject: [sdiy] Entirely OT: Tuscaloosa, AL
In-Reply-To: <89278f010804201937y164c399w5a821b4678812250@mail.gmail.com>
References: <89278f010804201937y164c399w5a821b4678812250@mail.gmail.com>
Message-ID: <480C2AF6.1080009@xavax.com>

Spencer Johnson wrote:
> Is anyone on list from Tuscaloosa, Alabama? I'm moving there soon,
> and I have some questions about the local audio scene, etc. Sorry
> for the OT post.

I am not from Tuscaloosa but as a Bama fan I've spent a lot of time
there. I will try to answer any questions you have. My home town is
Cullman which is about 90 minutes northeast of Tuscaloosa and about
halfway between Birmingham and Huntsville. I also lived 14 years in
The Rocket City and about 2 years in Birmingham. The latter is the
closest major city and has the nearest Guitar Center store. I'm not
aware of any music stores in Tuscaloosa but I'm sure there are some
since there is plenty of live music on "the strip" adjacent to the
University of Alabama campus. If you need advice on where to live,
I can hook you up with some friends who have lived there.

For a small fee I can provide directions to Dreamland BBQ which is
the best little rib shack in the known universe. :-)

-- 
Phil Harbison
keeper of the sauce, defender of the ribs




From pfperry at melbpc.org.au  Mon Apr 21 08:06:00 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 21 Apr 2008 16:06:00 +1000
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <480C2860.1000300@sonic.net>
Message-ID: <008001c8a375$c6fed630$8501a8c0@ice9>

The Linear Technology app note AN3 is full of goodness:
http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1203,P1248,D
4100

paul perry Melbourne Australia

>> There are a thick appnote paper from Linear Tech with designs
>> and theory around charge balanced oscillators. Available from
>> their site. It's a nice complementary to the Chroma service 
>> manual to understand and setup lab tests for your students. 
>Do you have an app note number (ANxxxx) or a lnk?




From usenet at teply.info  Mon Apr 21 08:06:47 2008
From: usenet at teply.info (Florian E. Teply)
Date: Mon, 21 Apr 2008 08:06:47 +0200
Subject: [sdiy] USB and the art of MIDI
In-Reply-To: <200804191258.07721.Stromeko@nexgo.de>
References: <5.1.0.14.2.20080419130019.0292cea0@mail.all-electric.com>
	<200804191258.07721.Stromeko@nexgo.de>
Message-ID: <480C2EF7.2030404@teply.info>

ASSI schrieb:
> On Samstag 19 April 2008, Batz Goodfortune wrote:
>> Y-ellow Humans.
>>          I'm wondering if anyone here has tried those little, Cheap,
>> Chinese USB to MIDI adaptors? More specifically, has anyone tried
>> using 2 or more out of a hub at the same time?
> 
> That should work in principle, but I'd rather use a USB2.0 high-speed 
> hub if more than four MIDI interfaces are in use at full bore.
> 
>> Even more specifically, I'm wondering if it might be possible to make
>> an ad-hock, expandable, multi-MIDI interface with say 10 or more
>> I/Os. I'm not worried about the electrical limitations. IE: Power
>> consumption and so fourth. I can take care of that with suitable
>> hacks. All I'm interested in is if the computer would see multiple
>> individual MIDI interfaces or get thoroughly confused and see them
>> all as just one single MIDI interface. Or something in between?
> 
> Depends on what you mean by "computer".  With a modern Linux I don't see 
> any problem, and all interfaces should show up as seperate devices 
> (they may have multiple ports).  Getting them to always use the same 
> device name and MIDI port number in ALSA will be a bit tricky however, 
> normally they will show up in the order they are found during device 
> discovery.  MIDI interfaces which need a driver downloaded at each 
> plug-in also often require manual configuration, but class-compliant 
> interfaces just work.  If the USB descriptors are halfway 
> spec-compliant each interface is listed with the name given by the 
> manufacturer so it is relatively easy to tell them apart.
> 
Well, the device naming (device names being the same after reboot, with 
names just as you like 'em) is a non-issue with udev, wich nowadays 
controls most devices. Usually, each device has some sort of unique 
identifier (MAC Address on ethernet cards or hard coded serial number 
for example). With that information udev can rearrange device names 
automagically with proper configuration.

I don't recall how to configure this right now though, but could look it 
up if needed.

Greetings
Florian


From lanterma at ece.gatech.edu  Mon Apr 21 08:46:27 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 21 Apr 2008 02:46:27 -0400
Subject: [sdiy] Lectures from this year's synthesizer class now all online
Message-ID: <C7587CA8-686C-4370-B8E7-263601063EBA@ece.gatech.edu>

I've finally got videos of all the lectures from the Spring 2008  
version of my class on "Electronics for Music Synthesis" posted to  
blip.tv. Previous versions of the class were called "Theory and Design  
of Music Synthesizers" - I retitled the class to more clearly  
indicated the increased analog focus and decreased digital focus of  
this version of the class (but there's some random bits of DSP-ish  
stuff in there, like discussions of aliasing).

There were 22 lectures this semester. Alas only 21 are posted, since I  
had technical issues with the camera one day.

The website is: http://users.ece.gatech.edu/~lanterma/ems

Come enjoy the videos - and also try your hand at the homeworks if  
you're looking for some fun. ;)

The last session, titled "Odds and Ends," has an analysis of the  
Buchla LPG tucked away in it. The Moog ladder appears somewhere in the  
"4-pole with feedback" lectures. (Note that I screw up the formula for  
the frequency response, since I analyze a single-sided ladder in  
lecture and then was sloppy when I put in the other side - Tim  
Stinchcombe's writeup set me straight. Actually I say a lot of  
incorrect and/or incoherent things in the lectures. I hope I'm right  
more often than wrong, and that they're at least entertaining.)

These videos were taken with a consumer camcorder that I just stuck on  
an overhead projector. The lectures from an earlier version of the  
class, at
users.ece.gatech.edu/~lanterma/ece4803, were professionally taped  
(since they were piped to our remote campus in Savannah), and are  
still available, but I knew less what I was doing then.

Anyway, a plea for help:

If you find these useful (either the old videos, or the new ones, or  
both) , and would like to make a "shareware" style donation - say $10  
or $25 or something - to support student projects (both for the formal  
class and independent study projects, which I sometimes advise  
students on), please see here:

http://users.ece.gatech.edu/~lanterma/ece4803/donations.html

You can write this off on your taxes as a donation, and it would also  
help justify my synth obsession to my superiors.

- Aaron 


From neil.johnson97 at ntlworld.com  Mon Apr 21 11:03:08 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Mon, 21 Apr 2008 9:03:08 +0000
Subject: [sdiy] Any LM331 experts around?
Message-ID: <20080421090338.KCOP17393.aamtaout02-winn.ispmail.ntl.com@smtp.ntlworld.com>

Ian,

> Mystery revealed.

And described in:

http://www.stanford.edu/class/ee122/Parts_Info/datasheets/LM331-AN-C.pdf

on page 4.  Courtesy of Mr. Pease, of course.

In your example the transistor is providing the bias, in Bob's example it is two diodes.  But its the same trick.

Neil

--
http://www.njohnson.co.uk

-----------------------------------------
Email sent from www.virginmedia.com/email
Virus-checked using McAfee(R) Software and scanned for spam



From ijfritz at comcast.net  Mon Apr 21 15:36:10 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Mon, 21 Apr 2008 07:36:10 -0600
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <20080421090338.KCOP17393.aamtaout02-winn.ispmail.ntl.com@s
	mtp.ntlworld.com>
References: <20080421090338.KCOP17393.aamtaout02-winn.ispmail.ntl.com@smtp.ntlworld.com>
Message-ID: <6.2.1.2.2.20080421072843.02148958@mail.comcast.net>

At 03:03 AM 4/21/2008, Neil Johnson wrote:

> > Mystery revealed.
>
>And described in:
>
>http://www.stanford.edu/class/ee122/Parts_Info/datasheets/LM331-AN-C.pdf


Mmmmm ... sorta. :-)

He's talking there about compensating the timing-cap tempco in the low-freq 
circuit.  In the high-freq circuit the drift is much larger and I think due 
to something else.  Look carefully at the amount of extra current being 
supplied and I think you will see what I mean.

Ian 



From ijfritz at comcast.net  Mon Apr 21 16:55:53 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Mon, 21 Apr 2008 08:55:53 -0600
Subject: [sdiy] Any LM331 experts around?
In-Reply-To: <6.2.1.2.2.20080421072843.02148958@mail.comcast.net>
References: <20080421090338.KCOP17393.aamtaout02-winn.ispmail.ntl.com@smtp.ntlworld.com>
	<6.2.1.2.2.20080421072843.02148958@mail.comcast.net>
Message-ID: <6.2.1.2.2.20080421083842.020e5708@mail.comcast.net>

At 07:36 AM 4/21/2008, Ian Fritz wrote:
>At 03:03 AM 4/21/2008, Neil Johnson wrote:
>
>> > Mystery revealed.
>>
>>And described in:
>>
>>http://www.stanford.edu/class/ee122/Parts_Info/datasheets/LM331-AN-C.pdf
>
>
>Mmmmm ... sorta. :-)
>
>He's talking there about compensating the timing-cap tempco in the 
>low-freq circuit.  In the high-freq circuit the drift is much larger and I 
>think due to something else.  Look carefully at the amount of extra 
>current being supplied and I think you will see what I mean.

To clarify further ... the double-diode compensator Neil pointed to 
*increases* the reference current as temperature increases.  This 
compensates for the decrease in capacitance of the polystyrene timing cap, 
which causes the output frequency to increase with temperature..

The transistor compensator, OTOH, *decreases* the reference current as 
temperature increases.  This compensates the large tempco of the chip in 
the high-frequency circuit.  This drift causes the output frequency to 
decrease with increasing temperature.  I verified that the chip was the 
source of the drift by individually heating each component in the 
circuit.  Except for the cryptic transistor compensator, there seems to be 
no explicit mention by National of this much larger (internal) drift in the 
high-frequency circuit.

Old cartoon:  Two rocket scientists are looking at a missle with its nose 
buried straght into the ground.  One turns to the other and says: "Sign error".

Ian 



From neil.johnson97 at ntlworld.com  Mon Apr 21 17:49:45 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Mon, 21 Apr 2008 15:49:45 +0000
Subject: [sdiy] Any LM331 experts around?
Message-ID: <20080421154844.CUMK29112.aamtaout04-winn.ispmail.ntl.com@smtp.ntlworld.com>

Hi Ian,

Ian Fritz <ijfritz at comcast.net> wrote:
> At 07:36 AM 4/21/2008, Ian Fritz wrote:
> >At 03:03 AM 4/21/2008, Neil Johnson wrote:
> >
> >> > Mystery revealed.
> >>
> >>And described in:
> >>
> >>http://www.stanford.edu/class/ee122/Parts_Info/datasheets/LM331-AN-C.pdf
> >
> >
> >Mmmmm ... sorta. :-)
> >
> >He's talking there about compensating the timing-cap tempco in the 
> >low-freq circuit.  In the high-freq circuit the drift is much larger and I 
> >think due to something else.  Look carefully at the amount of extra 
> >current being supplied and I think you will see what I mean.
> 
> To clarify further ... the double-diode compensator Neil pointed to 
> *increases* the reference current as temperature increases.  This 
> compensates for the decrease in capacitance of the polystyrene timing cap, 
> which causes the output frequency to increase with temperature..
> 
> The transistor compensator, OTOH, *decreases* the reference current as 
> temperature increases.  This compensates the large tempco of the chip in 
> the high-frequency circuit.  This drift causes the output frequency to 
> decrease with increasing temperature.  I verified that the chip was the 
> source of the drift by individually heating each component in the 
> circuit.  Except for the cryptic transistor compensator, there seems to be 
> no explicit mention by National of this much larger (internal) drift in the 
> high-frequency circuit.

One difference is that the diode compensated circuit is a F/V converter, while the transistor compensated circuit is V/F.  Assuming I haven't confused my temp.coeffs (TC) and assuming a polystyrene capacitor with, say, -100 ppm/'C TC, the F/V converter output voltage would *decrease* with increasing temperature, so exhibiting the same TC sign as the capacitor.  Whereas in the V/F converter the output frequency would *increase* with temperature, so exhibiting the opposite TC sign as the capacitor.

(I think - I may be wrong :)

You're right about the magnitude of the compensating current being quite a bit higher by a factor of about 10 (hand-waving quickie SPICE simulation of the 2N2222 compensation circuit).  Of course, the *change* (i.e. the TC) in the compensating current is the same, about 3200ppm/'C.

This'll give me something to think about on holiday!

Cheers,
Neil
--


--
http://www.njohnson.co.uk

-----------------------------------------
Email sent from www.virginmedia.com/email
Virus-checked using McAfee(R) Software and scanned for spam



From Stromeko at nexgo.de  Mon Apr 21 19:45:08 2008
From: Stromeko at nexgo.de (ASSI)
Date: Mon, 21 Apr 2008 19:45:08 +0200
Subject: [sdiy] USB,MIDI,SCSI
In-Reply-To: <480BA85C.5040800@eventualdecline.com>
References: <4894.95852.qm@web32706.mail.mud.yahoo.com>
	<480BA85C.5040800@eventualdecline.com>
Message-ID: <200804211945.08717.Stromeko@nexgo.de>

On Sonntag 20 April 2008, Ben Lincoln wrote:
> SCSI <-> Compact Flash adapter and storing everything on a CF card.

You wouldn't per chance know of a source for these?  IDE to CF adapters 
are easy to get, but I can't find any SCSI (50pin) to CF adapters to 
buy new.  Sometimes you find some used, but never with enough 
information to make sure that it would work (and at prices that don't 
suggest a shot into the dark).


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

SD adaptation for Waldorf rackAttack V1.04R1:
http://Synth.Stromeko.net/Downloads.html#WaldorfSDada



From aankrom at bluemarble.net  Mon Apr 21 20:13:56 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 21 Apr 2008 14:13:56 -0400
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge to
	modify...
References: <008001c8a375$c6fed630$8501a8c0@ice9>
Message-ID: <01d101c8a3db$78eca880$0202a8c0@positronium>

Hi guys,

So I have one Realistic Electronic Reverb: the greatest effect to use for 
not quite what it was intended for. This booger is a great noisemaker and 
lots of fun with it's slider controls. It's even better with a few tweaks to 
the circuit: more gain and high-end roll-off to the regen path, 471pF 
polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place of 
the AN6550's, socket for the timing cap to play with different values, 
adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've thought 
about wiring 2 or 3 in series, the BL3208A being something like $3.75 in 
price. Next planned mod is making the "DEPTH" control into a true wet/dry 
crossfader, which is a non-trivial task, but not impossible: I think a 1 uf 
cap and a couple 100kOhm resistors to put the bias in the right place again 
and cutting the traces on the PCB and rewiring accordingly.

SO I've been trying to buy another one on eBay for what I got my first one 
for ($12.00) and it's been a daunting task. People are catching on to how 
cool these are.

I'm not one to care much for collectability in gear because I like to be 
able to use my gear to the fullest. But I'm planning some more mods that 
will actuall involve cutting into the unit and I'm beginning to wonder 
whether I should. I wanted to add a DP3T selector switch to select between 
various timing caps (if I can just find a good place on the front for a 
toggle switch to go...), and adding some brass body contacts to bring it 
(sort of) into the realm of circuit bending. I must admit that I don't 
actually hold to the philosphy of circuit bending although I enjoy hearing 
some of the results. I don't think wiring various contacts and capacitors to 
the timing cap connections could be considered circuit bending in its true 
spirit because they are not random bends, but carefully thought out 
connections. Putting your fingers across the timing cap terminals is very 
fun: it depends on the pressure exerted so it has a playability factor to 
it: you can quickly (or slowly) descend into the realm of 2 second delays 
and back again. With the increased number of stages in the BL3208A, it's 
even better: repeats just go on and on without sounding like an oscillation, 
but it'll oscillate too - and how!

So I'm wondering: should I do it? I mean even when they're going at $40 on 
eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
something.

Also, if anyone has DONE the wet/dry crossfade mod and would like to share, 
I'd appreciate that a lot. Thanx...


Cheers,
Anthony 




From colin at colinfraser.com  Mon Apr 21 20:17:17 2008
From: colin at colinfraser.com (Colin f)
Date: Mon, 21 Apr 2008 19:17:17 +0100
Subject: [sdiy] USB,MIDI,SCSI
In-Reply-To: <200804211945.08717.Stromeko@nexgo.de>
Message-ID: <001601c8a3dc$000f3b70$0101a8c0@zen2>

 
> On Sonntag 20 April 2008, Ben Lincoln wrote:
> > SCSI <-> Compact Flash adapter and storing everything on a CF card.
> 
> You wouldn't per chance know of a source for these?  IDE to 
> CF adapters 
> are easy to get, but I can't find any SCSI (50pin) to CF adapters to 
> buy new.  Sometimes you find some used, but never with enough 
> information to make sure that it would work (and at prices that don't 
> suggest a shot into the dark).

I got some MicroTech PCD-47Bs from www.scsiforsamplers.com
Note that these don't run in synchronous mode, so the data transfer rate is
more like a Zip disk than a hard drive.
But they work nicely.

Cheers,
Colin f







From aankrom at bluemarble.net  Mon Apr 21 20:27:24 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 21 Apr 2008 14:27:24 -0400
Subject: [sdiy] Strobe tuners & synchronous motors rerevisited
References: <008001c8a375$c6fed630$8501a8c0@ice9>
Message-ID: <01d201c8a3dd$5a63f7e0$0202a8c0@positronium>

I found an induction motor from an old clock that had a magnetic rotor. Do 
you think that would work sufficitently as a synchronous motor for a strobe 
tuner? With the gear train removed, it doesn't have a lot of torque and the 
direction it will turn is indeterminate (is that what the startinng motor is 
for on Hammond organs?). I know some synchronous motors have designs with 
definite rotation direction that's usually selectable. I also wondered if 
this motor motor I got from an 8-track recorder is a synchronous motor: it 
runs right off of the AC line at 117VAC (In Japan maybe) with a speed of 
18,000 RPM... It's a cool motor at any rate.

Incidently, the old Hammond organs that I can get for cheap or M100's and 
L100's, not M3's does that make it less of a sin to use them for parts? I 
know John Paul Jones used an L100... But I think I could just use the reverb 
amp from it and try to restore the rest of the organ. I suppose if I got 
enough of them I could get into the business of Hammond organ restoration. 
That and Wurlitzer Sidemans (Sidemen?). I've seen many videos of Sidemen on 
YouTube and all I can say is: I want one! Or I could make something like it. 
I've long thought of some kind of electromechanical sequencer. The Sideman's 
method of tempo change is clever

Cheers,
Anthony 




From subjectivity at hotmail.com  Mon Apr 21 20:42:10 2008
From: subjectivity at hotmail.com (Dan Snazelle)
Date: Mon, 21 Apr 2008 18:42:10 +0000
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
	to	modify...
In-Reply-To: <01d101c8a3db$78eca880$0202a8c0@positronium>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
Message-ID: <BAY144-W2153E39A6D5AE938F17353C8E10@phx.gbl>


wow
you make me want to get one (again)

i used to love putting my guitar through this and playing the sliders with my bare feet in time to the music!
eventually though, such behavior busted the sliders and this was LOOONG before i knew how to repair things.

is there a schematic for this box around?

your mods sound great...certainly I am also starting to have an interest in planned out circuit bending.
However, i dont make as much of a distinction as you do.I dont think ALL circuit benders just randomly look for points to mess with (some do of course, and some hold this up as a philosophy), i think a lot of it depends on the amount of electronic knowledge you have going into it. But i think the goal is the same-to make messed up sounds.

i wish radio shack still had half the cool stuff they used to! My junior high band used to use three or four of those 4 channel mixers they used to make connected in series to record our band to boombox, along with some of those cheapo PZM mics they used to sell (the small ones)

oh how i wish it wasnt just a phone store now. :(

sorry for the rant





From rtellason at verizon.net  Mon Apr 21 20:59:45 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Mon, 21 Apr 2008 14:59:45 -0400
Subject: [sdiy] Strobe tuners & synchronous motors rerevisited
In-Reply-To: <01d201c8a3dd$5a63f7e0$0202a8c0@positronium>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d201c8a3dd$5a63f7e0$0202a8c0@positronium>
Message-ID: <200804211459.45733.rtellason@verizon.net>

On Monday 21 April 2008 14:27, anthony wrote:
> I found an induction motor from an old clock that had a magnetic rotor. Do
> you think that would work sufficitently as a synchronous motor for a strobe
> tuner? With the gear train removed, it doesn't have a lot of torque and the
> direction it will turn is indeterminate (is that what the startinng motor
> is for on Hammond organs?).

No,  the starting motor is because synchronous motors back then didn't have 
enough torque to get things going,  though they could keep them going once 
you got some momentum built up.

No way should a clock motor be indeterminate as to direction!  There's usually 
a "shaded pole" (looks like a loop of heavy wire) that decides that.

> I know some synchronous motors have designs with definite rotation direction
> that's usually selectable. I also wondered if this motor motor I got from an
> 8-track recorder is a synchronous motor: it runs right off of the AC line at
> 117VAC (In Japan maybe) 

Japan uses 100VAC.

> with a speed of 18,000 RPM... It's a cool motor at any rate. 
>
> Incidently, the old Hammond organs that I can get for cheap or M100's and
> L100's, not M3's does that make it less of a sin to use them for parts?

No.  :-(


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From somnium7 at gmail.com  Mon Apr 21 21:35:35 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Mon, 21 Apr 2008 15:35:35 -0400
Subject: [sdiy] Strobe tuners & synchronous motors rerevisited
In-Reply-To: <200804211459.45733.rtellason@verizon.net>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d201c8a3dd$5a63f7e0$0202a8c0@positronium>
	<200804211459.45733.rtellason@verizon.net>
Message-ID: <916920440804211235h6ae504daga06a099020e7f5f5@mail.gmail.com>

If you are gonna hack up old Hammonds look for the old spinets like I
have - 524 or similar. Some people are begging to have them taken out
of their garages these days. I got mine for $50 in a consignment shop.
It has most of the same stuff as other Hammonds have inside but solid
state electronics.
I have been hotrodding mine over the past year or so and have it
sounding pretty close to an M series now.

The classics need to preserved. Rip up the spinets, they have no
vintage appeal to anybody.

Mike

On Mon, Apr 21, 2008 at 2:59 PM, Roy J. Tellason <rtellason at verizon.net> wrote:
> On Monday 21 April 2008 14:27, anthony wrote:
>  > I found an induction motor from an old clock that had a magnetic rotor. Do
>  > you think that would work sufficitently as a synchronous motor for a strobe
>  > tuner? With the gear train removed, it doesn't have a lot of torque and the
>  > direction it will turn is indeterminate (is that what the startinng motor
>  > is for on Hammond organs?).
>
>  No,  the starting motor is because synchronous motors back then didn't have
>  enough torque to get things going,  though they could keep them going once
>  you got some momentum built up.
>
>  No way should a clock motor be indeterminate as to direction!  There's usually
>  a "shaded pole" (looks like a loop of heavy wire) that decides that.
>
>  > I know some synchronous motors have designs with definite rotation direction
>  > that's usually selectable. I also wondered if this motor motor I got from an
>  > 8-track recorder is a synchronous motor: it runs right off of the AC line at
>  > 117VAC (In Japan maybe)
>
>  Japan uses 100VAC.
>
>  > with a speed of 18,000 RPM... It's a cool motor at any rate.
>  >
>  > Incidently, the old Hammond organs that I can get for cheap or M100's and
>  > L100's, not M3's does that make it less of a sin to use them for parts?
>
>  No.  :-(
>
>
>  --
>  Member of the toughest, meanest, deadliest, most unrelenting -- and
>  ablest -- form of life in this section of space,  a critter that can
>  be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>  -
>  Information is more dangerous than cannon to a society ruled by lies. --James
>  M Dakin
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From lanterma at ece.gatech.edu  Mon Apr 21 22:15:27 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 21 Apr 2008 16:15:27 -0400
Subject: [sdiy] Deciphering Roland 100 filter schematic
Message-ID: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>

Howdy,

I'm meeting right now with my student Billy, who is working on making  
a version of the Roland 100 VCF:

http://fa.utfs.org/diy/roland100/101_op27.jpg

See the bottom half, 3rd "block" from the left.

1) There's a row of pots at the top of the filter (on the schematic),  
that is that have notations like "100kA" and "100kB". VR305 is like  
that too, it's marked "100 kB". Any ideas of what the A and B  
notations mean?

2) Several of the caps, such as C321, C322, C323 have notations on  
them like "10/16 N.p" and "100/16." I'm guessing N.p means "not  
polarized," but I'm not sure about the slash notation. What do those  
notations mean? They look like something from the mad hatter in Alice  
in wonderland. (Most of the other caps have microfarad markings.)

We're also trying to decipher the resonance pot. There's two variable  
resistors ganged together.

3) What do the circles that are tied to ground just below the variable  
resistors indicate?

4) Related to 3 - should we interpret the variable resistors as one  
end tied to a pot, another end tied to the wiper, and the other end  
left floating? Or is that ground marking somehow important?

5) I see what the "right" resonance pot is doing - it looks like it  
controls the amount of feedback to the negative part of the diff pair  
at the bottom of the diode ladder. But what is the other pot, the one  
that connects "A" and "B" (just to the upper right of FET Q314, which  
looks to be a buffer) doing?

5) Is VR305 a trim to adjust the DC bias point on the left side of the  
ladder to make it match that on the right? That's my intuition.

- Aaron



From tensiontype at hotmail.com  Mon Apr 21 22:25:02 2008
From: tensiontype at hotmail.com (Sean Ellis)
Date: Mon, 21 Apr 2008 22:25:02 +0200
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
	tomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
Message-ID: <BAY144-DAV95837B79F09B7975D8FFEB3E10@phx.gbl>

With some changes and additions I turned one of these into a quite decent 
rack mounted flanger with envelope follower.


----- Original Message ----- 
From: "anthony" <aankrom at bluemarble.net>
To: <Synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 21, 2008 8:13 PM
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge 
tomodify...


> Hi guys,
>
> So I have one Realistic Electronic Reverb: the greatest effect to use for 
> not quite what it was intended for. This booger is a great noisemaker and 
> lots of fun with it's slider controls. It's even better with a few tweaks 
> to the circuit: more gain and high-end roll-off to the regen path, 471pF 
> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place 
> of the AN6550's, socket for the timing cap to play with different values, 
> adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've thought 
> about wiring 2 or 3 in series, the BL3208A being something like $3.75 in 
> price. Next planned mod is making the "DEPTH" control into a true wet/dry 
> crossfader, which is a non-trivial task, but not impossible: I think a 1 
> uf cap and a couple 100kOhm resistors to put the bias in the right place 
> again and cutting the traces on the PCB and rewiring accordingly.
>
> SO I've been trying to buy another one on eBay for what I got my first one 
> for ($12.00) and it's been a daunting task. People are catching on to how 
> cool these are.
>
> I'm not one to care much for collectability in gear because I like to be 
> able to use my gear to the fullest. But I'm planning some more mods that 
> will actuall involve cutting into the unit and I'm beginning to wonder 
> whether I should. I wanted to add a DP3T selector switch to select between 
> various timing caps (if I can just find a good place on the front for a 
> toggle switch to go...), and adding some brass body contacts to bring it 
> (sort of) into the realm of circuit bending. I must admit that I don't 
> actually hold to the philosphy of circuit bending although I enjoy hearing 
> some of the results. I don't think wiring various contacts and capacitors 
> to the timing cap connections could be considered circuit bending in its 
> true spirit because they are not random bends, but carefully thought out 
> connections. Putting your fingers across the timing cap terminals is very 
> fun: it depends on the pressure exerted so it has a playability factor to 
> it: you can quickly (or slowly) descend into the realm of 2 second delays 
> and back again. With the increased number of stages in the BL3208A, it's 
> even better: repeats just go on and on without sounding like an 
> oscillation, but it'll oscillate too - and how!
>
> So I'm wondering: should I do it? I mean even when they're going at $40 on 
> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
> something.
>
> Also, if anyone has DONE the wet/dry crossfade mod and would like to 
> share, I'd appreciate that a lot. Thanx...
>
>
> Cheers,
> Anthony
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From mverbos at earthlink.net  Mon Apr 21 22:44:43 2008
From: mverbos at earthlink.net (mark verbos)
Date: Mon, 21 Apr 2008 16:44:43 -0400
Subject: [sdiy] CMOS clock problem
Message-ID: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>

Hi,

I have a high frequency clock made out of a couple 4001 gates in my  
quantizer module. It doesn't like to start clocking when I turn it  
on. Then I touch the pins with the scope probe and it starts going. I  
tried adding a 2.2M resistor to ground on the pin where the cap  
connects and I got it to start if I plug the connector in while the  
cabinet is powered up, but if I power cycle it while plugged in it's  
not oscillating. Is this something to do with the order that the  
power rails are coming up? It's only using +15 and GND, so I don't  
see how it could.

Any ideas? I'm lost.


Mark


From gene at ixiacom.com  Mon Apr 21 22:47:41 2008
From: gene at ixiacom.com (Gene Stopp)
Date: Mon, 21 Apr 2008 13:47:41 -0700
Subject: [sdiy] Deciphering Roland 100 filter schematic
In-Reply-To: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
References: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
Message-ID: <0A2F39512D881F4690CF73625E4161F52BC8A1@IXCA-EXCHANGE.ixiacom.com>

Here's a stab:

1) Taper?

2) Microfarads/volts, e.g. 10 microfarads at 16 volts

3) Coax cables with the shields grounded

4) Yes, either that or one end plus wiper tied together, and the other
end, as the two connections

5) Volume change compensation so that turning up the resonance doesn't
drop the volume. A typical ladder filter can have a substantial volume
drop when the resonance is increased.

6) I believe so, this is an offset trim to keep both sides of the ladder
balanced.


- Gene
 

Howdy,

I'm meeting right now with my student Billy, who is working on making  
a version of the Roland 100 VCF:

http://fa.utfs.org/diy/roland100/101_op27.jpg

See the bottom half, 3rd "block" from the left.

1) There's a row of pots at the top of the filter (on the schematic),  
that is that have notations like "100kA" and "100kB". VR305 is like  
that too, it's marked "100 kB". Any ideas of what the A and B  
notations mean?

2) Several of the caps, such as C321, C322, C323 have notations on  
them like "10/16 N.p" and "100/16." I'm guessing N.p means "not  
polarized," but I'm not sure about the slash notation. What do those  
notations mean? They look like something from the mad hatter in Alice  
in wonderland. (Most of the other caps have microfarad markings.)

We're also trying to decipher the resonance pot. There's two variable  
resistors ganged together.

3) What do the circles that are tied to ground just below the variable  
resistors indicate?

4) Related to 3 - should we interpret the variable resistors as one  
end tied to a pot, another end tied to the wiper, and the other end  
left floating? Or is that ground marking somehow important?

5) I see what the "right" resonance pot is doing - it looks like it  
controls the amount of feedback to the negative part of the diff pair  
at the bottom of the diode ladder. But what is the other pot, the one  
that connects "A" and "B" (just to the upper right of FET Q314, which  
looks to be a buffer) doing?

5) Is VR305 a trim to adjust the DC bias point on the left side of the  
ladder to make it match that on the right? That's my intuition.

- Aaron

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From samppa.tolvanen at gmail.com  Mon Apr 21 22:50:11 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Mon, 21 Apr 2008 23:50:11 +0300
Subject: [sdiy] Deciphering Roland 100 filter schematic
In-Reply-To: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
References: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
Message-ID: <fa1b0bd80804211350p446e57b9te18938b2cfc2e4ad@mail.gmail.com>

Hey, this ain't that bad? ;)

On 4/21/08, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:

>
>  1) There's a row of pots at the top of the filter (on the schematic), that
> is that have notations like "100kA" and "100kB". VR305 is like that too,
> it's marked "100 kB". Any ideas of what the A and B notations mean?
>

Wouldn't we this time be pretty sure "B" stands for Linear and A for
"Log". standards standards...

>  2) Several of the caps, such as C321, C322, C323 have notations on them
> like "10/16 N.p" and "100/16." I'm guessing N.p means "not polarized," but
> I'm not sure about the slash notation. What do those notations mean? They
> look like something from the mad hatter in Alice in wonderland. (Most of the
> other caps have microfarad markings.)
>
I'd go for 10uF/16V ect.

>  We're also trying to decipher the resonance pot. There's two variable
> resistors ganged together.
>
>  3) What do the circles that are tied to ground just below the variable
> resistors indicate?
>

Connection is run thru shielded cable.

>  4) Related to 3 - should we interpret the variable resistors as one end
> tied to a pot, another end tied to the wiper, and the other end left
> floating? Or is that ground marking somehow important?
>

Yes. (see H.P.F.)

>  5) I see what the "right" resonance pot is doing - it looks like it
> controls the amount of feedback to the negative part of the diff pair at the
> bottom of the diode ladder. But what is the other pot, the one that connects
> "A" and "B" (just to the upper right of FET Q314, which looks to be a
> buffer) doing?
>

Wouldn't that be sort of "gain correction" for the high Q-settings,
R351 paralled with R352 and resonance pot combination?

...Samppa


From mverbos at earthlink.net  Mon Apr 21 22:52:28 2008
From: mverbos at earthlink.net (mark verbos)
Date: Mon, 21 Apr 2008 16:52:28 -0400
Subject: [sdiy] Deciphering Roland 100 filter schematic
In-Reply-To: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
References: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
Message-ID: <6D31DEC5-55A2-4499-AA36-93849F3C54ED@earthlink.net>


On Apr 21, 2008, at 4:15 PM, Aaron Lanterman wrote:

> Howdy,
>
> I'm meeting right now with my student Billy, who is working on  
> making a version of the Roland 100 VCF:
>
> http://fa.utfs.org/diy/roland100/101_op27.jpg
>
> See the bottom half, 3rd "block" from the left.
>
> 1) There's a row of pots at the top of the filter (on the  
> schematic), that is that have notations like "100kA" and "100kB".  
> VR305 is like that too, it's marked "100 kB". Any ideas of what the  
> A and B notations mean?

it's the pot taper. A is audio, B is linear and C is reverse audio


>
> 2) Several of the caps, such as C321, C322, C323 have notations on  
> them like "10/16 N.p" and "100/16." I'm guessing N.p means "not  
> polarized," but I'm not sure about the slash notation. What do  
> those notations mean? They look like something from the mad hatter  
> in Alice in wonderland. (Most of the other caps have microfarad  
> markings.)

value in farads/voltage rating    n.p. is non-polarized

>
> We're also trying to decipher the resonance pot. There's two  
> variable resistors ganged together.

The resonance control compensates for the gain loss as you add  
feedback to the filter.
>
> 3) What do the circles that are tied to ground just below the  
> variable resistors indicate?

those join up with the A and B in circles near the FET on the other  
side of the ladder.

>
> 4) Related to 3 - should we interpret the variable resistors as one  
> end tied to a pot, another end tied to the wiper, and the other end  
> left floating? Or is that ground marking somehow important?

I think they mean to indicate that the wire to the pot is shielded. I  
would wire the pot as you said.

>
> 5) I see what the "right" resonance pot is doing - it looks like it  
> controls the amount of feedback to the negative part of the diff  
> pair at the bottom of the diode ladder. But what is the other pot,  
> the one that connects "A" and "B" (just to the upper right of FET  
> Q314, which looks to be a buffer) doing?

changing the gain going into the filter


>
> 5) Is VR305 a trim to adjust the DC bias point on the left side of  
> the ladder to make it match that on the right? That's my intuition.
>
> - Aaron
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From blincoln at eventualdecline.com  Mon Apr 21 22:58:36 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 21 Apr 2008 13:58:36 -0700 (PDT)
Subject: [sdiy] Deciphering Roland 100 filter schematic
In-Reply-To: <0A2F39512D881F4690CF73625E4161F52BC8A1@IXCA-EXCHANGE.ixiacom.com>
References: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu>
	<0A2F39512D881F4690CF73625E4161F52BC8A1@IXCA-EXCHANGE.ixiacom.com>
Message-ID: <15735.38.112.225.84.1208811516.squirrel@www.eventualdecline.com>

On Mon, April 21, 2008 1:47 pm, Gene Stopp said:

> 1) Taper?

That's what I was thinking. Alpha pots have an A ("Audio") or B ("There is
no 'B' in 'linear'") in their part numbers to indicate taper.



From billbigrig at yahoo.com  Tue Apr 22 01:18:34 2008
From: billbigrig at yahoo.com (bill bigrig)
Date: Mon, 21 Apr 2008 16:18:34 -0700 (PDT)
Subject: [sdiy] USB,SCSI,MIDI
Message-ID: <973734.22441.qm@web32705.mail.mud.yahoo.com>

Howdy,

 Mainly, I want to know if i can take a SCSI device
Akai 5000, or Roland VS-2480-cd, and use USB storage.
Or is it better to try finding SCSI hard drives used?
Can they be bought new? Not to mention the cable
issue(large/small) I have a CD-ROM for the Akai 5000
to run my Mellotron sounds. That's all I've done. but
if I collect samples  and load them in, go to all the
trouble of keyboard mapping sound effects etc. Can it
be converted over to USB or should I just fish for
SCSI drives and cables.


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From Barry.L.Klein at wdc.com  Tue Apr 22 02:12:10 2008
From: Barry.L.Klein at wdc.com (Barry Klein)
Date: Mon, 21 Apr 2008 17:12:10 -0700
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <973734.22441.qm@web32705.mail.mud.yahoo.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
Message-ID: <6B16794FD98610449F66759BBF503D40CEDF93@wdscexbe03.sc.wdc.com>

Another question is whether this SCSI to firewire thing would work:
http://www.ratocsystems.com/english/products/FR1SX.html
If so, you could daisychain your synth, external HDD, (firewire)cardreader,
etc. all together with more manageable cables.
My worry about SCSI CDROM's is that the CDROM mechanisms don't last very
long and then what do you do...?  
There was at one time a SCSI to IDE bridge controller chip available from
Taiwan...  Never discovered whether it would work for this purpose.  Since I
have only a 2gig capable K2000 now only worth <$500 I just gave up and think
about other things...

Barry






From ka4hjh at gte.net  Tue Apr 22 02:27:58 2008
From: ka4hjh at gte.net (KA4HJH)
Date: Mon, 21 Apr 2008 20:27:58 -0400
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <6B16794FD98610449F66759BBF503D40CEDF93@wdscexbe03.sc.wdc.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
	<6B16794FD98610449F66759BBF503D40CEDF93@wdscexbe03.sc.wdc.com>
Message-ID: <p06240830c432e0226ed3@[192.168.1.101]>

>Another question is whether this SCSI to firewire thing would work:
>http://www.ratocsystems.com/english/products/FR1SX.html
>If so, you could daisychain your synth, external HDD, (firewire)cardreader,
>etc. all together with more manageable cables.

The consensus on DAW-Mac is that these are fine for running an old scanner
or optical drive but not any sort of high-performance HD stuff like
multi-track. Whether it would work with this this application is another
matter.

Does the unit in question have a limit as to drive capacity? I've heard
that the SCSI implementation in some samplers is rather iffy to begin with
so the only way to know for sure is to try it.

>My worry about SCSI CDROM's is that the CDROM mechanisms don't last very
>long and then what do you do...?

You have a pile of them like I do. Too bad I don't have any samplers.

>There was at one time a SCSI to IDE bridge controller chip available from
>Taiwan...  Never discovered whether it would work for this purpose.  Since I
>have only a 2gig capable K2000 now only worth <$500 I just gave up and think
>about other things...

Like I was saying...

Someday working SCSI drives will be worth as much as a 2040 or a 726.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"


From derennep at brutele.be  Tue Apr 22 02:29:56 2008
From: derennep at brutele.be (Philippe Derenne)
Date: Tue, 22 Apr 2008 02:29:56 +0200
Subject: [sdiy] Deciphering Roland 100 filter schematic
References: <5CCDDD1A-9E07-44D8-B9B4-8D16B985C880@ece.gatech.edu><0A2F39512D881F4690CF73625E4161F52BC8A1@IXCA-EXCHANGE.ixiacom.com>
	<15735.38.112.225.84.1208811516.squirrel@www.eventualdecline.com>
Message-ID: <003a01c8a40f$fe7a9410$0264a8c0@c2d266>

Hi Aaron and all,

My information about A, B and C pots is : it depends on the country :

Europe and USA :
    A (or no letter) : linear
    B : log
    C : anti-log

Japan :
    A (or no letter) : log
    B : linear
    C : anti-log
Do Japanese people have special ears ? ;^)

Have a look there (pages 2 and 4) : 
http://www.farnell.com/datasheets/19801.pdf

And if you look at the Roland schematic, upper right corner, the "phones 
level" pot is a B-type : this one at least must be a log one...
Now what if your schematic is "made in Japan" ???  ;^)

Hope this helps...

Phil.

----- Original Message ----- 
From: "Ben Lincoln" <blincoln at eventualdecline.com>
To: "SDIY" <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 21, 2008 10:58 PM
Subject: RE: [sdiy] Deciphering Roland 100 filter schematic


> On Mon, April 21, 2008 1:47 pm, Gene Stopp said:
>
>> 1) Taper?
>
> That's what I was thinking. Alpha pots have an A ("Audio") or B ("There is
> no 'B' in 'linear'") in their part numbers to indicate taper.
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From blincoln at eventualdecline.com  Tue Apr 22 02:49:06 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Mon, 21 Apr 2008 17:49:06 -0700
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <973734.22441.qm@web32705.mail.mud.yahoo.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
Message-ID: <480D3602.203@eventualdecline.com>

You can definitely buy new SCSI hard drives (although they might be 
*too* new - either in terms of the size or the interface, depending on 
how picky your gear is), as it was the interface of choice for server 
hardware up until about two years ago when SAS started taking over.

I would recommend again taking a look at a SCSI <-> CF adapter as 
opposed to USB. My thinking is that USB is a general-purpose interface 
like SCSI is, so finding a device that will do a good job of making a 
USB storage device look like a SCSI hard drive is going to be difficult 
or impossible. On the other hand, if you go for a drive-specific 
interface like CF (or IDE), you can almost certainly find something that 
will work. Plus, if you're storing things on CF cards it should be very 
easy to back them up by putting them in a card reader on your PC and 
making a disk image.

To answer Achim's question, I haven't worked with any yet myself - the 
projects on my list that would involve them are so far *down* the list 
that I might never get to them - but I did see a few options poking 
around online. There seem to be two main caveats - the synchronous mode 
that Colin mentioned, and also some seem to be read-only.

bill bigrig wrote:
>  Mainly, I want to know if i can take a SCSI device
> Akai 5000, or Roland VS-2480-cd, and use USB storage.
> Or is it better to try finding SCSI hard drives used?
> Can they be bought new? Not to mention the cable
> issue(large/small) I have a CD-ROM for the Akai 5000
> to run my Mellotron sounds. That's all I've done. but
> if I collect samples  and load them in, go to all the
> trouble of keyboard mapping sound effects etc. Can it
> be converted over to USB or should I just fish for
> SCSI drives and cables.
>   


From jays at aracnet.com  Tue Apr 22 03:03:31 2008
From: jays at aracnet.com (jays at aracnet.com)
Date: Mon, 21 Apr 2008 18:03:31 -0700
Subject: [sdiy] USB,SCSI,MIDI
Message-ID: <200804220103.m3M13Vii019226@sapphire.spiritone.com>

Another issue I'd be curious about is formatting. A lot of the samplers have their own disc format which is different than what a PC or MAC uses.

So a good question would be if the card readers can format media correctly for the sampler and use that format.

I have loaded samples into the sampler, re-did the keymapping and programming and saved them on my ZIP discs. So as long as you can write to the device you should be able to save your programs with data on the media. It'd be a manual process but should work.

Jay S.

> bill bigrig wrote:
> >  Mainly, I want to know if i can take a SCSI device
> > Akai 5000, or Roland VS-2480-cd, and use USB storage.
> > Or is it better to try finding SCSI hard drives used?
> > Can they be bought new? Not to mention the cable
> > issue(large/small) I have a CD-ROM for the Akai 5000
> > to run my Mellotron sounds. That's all I've done. but
> > if I collect samples  and load them in, go to all the
> > trouble of keyboard mapping sound effects etc. Can it
> > be converted over to USB or should I just fish for
> > SCSI drives and cables.
> >   
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From loscha at gmail.com  Tue Apr 22 07:14:33 2008
From: loscha at gmail.com (Loscha)
Date: Tue, 22 Apr 2008 15:14:33 +1000
Subject: [sdiy] Microchip PSG - AY8930
Message-ID: <17035a3d0804212214m40011c00j956c54b408504984@mail.gmail.com>

At the time of writing, Rockby Electronics in Clayton, Melbourne,
Australia have 30 of these in stock, at $5 a piece.

Does anyone use these anymore?

http://www.rockby.com.au/catresults.cfm?stock_no=22570&imageField2.x=0&imageField2.y=0


From cbergmiller at gmail.com  Tue Apr 22 09:14:08 2008
From: cbergmiller at gmail.com (Christian Bergmiller)
Date: Tue, 22 Apr 2008 09:14:08 +0200
Subject: [sdiy] CMOS clock problem
In-Reply-To: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>
References: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>
Message-ID: <8bb8f7150804220014u797341dcre86d0e632136f404@mail.gmail.com>

4001 lacks the "schmitt trigger" capability
40106 would perhaps be a better choice?

have you tried a small capacitor to the high rail?
(instead of the 2.2M resistor to ground)

 just some ideas..

christian


2008/4/21, mark verbos <mverbos at earthlink.net>:
> Hi,
>
> I have a high frequency clock made out of a couple 4001 gates in my
> quantizer module. It doesn't like to start clocking when I turn it on. Then
> I touch the pins with the scope probe and it starts going. I tried adding a
> 2.2M resistor to ground on the pin where the cap connects and I got it to
> start if I plug the connector in while the cabinet is powered up, but if I
> power cycle it while plugged in it's not oscillating. Is this something to
> do with the order that the power rails are coming up? It's only using +15
> and GND, so I don't see how it could.
>
> Any ideas? I'm lost.
>
>
> Mark
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From usenet at teply.info  Tue Apr 22 09:36:20 2008
From: usenet at teply.info (Florian E. Teply)
Date: Tue, 22 Apr 2008 09:36:20 +0200
Subject: [sdiy] Lectures from this year's synthesizer class now all online
In-Reply-To: <C7587CA8-686C-4370-B8E7-263601063EBA@ece.gatech.edu>
References: <C7587CA8-686C-4370-B8E7-263601063EBA@ece.gatech.edu>
Message-ID: <480D9574.4060105@teply.info>

Aaron Lanterman schrieb:
> I've finally got videos of all the lectures from the Spring 2008 version 
> of my class on "Electronics for Music Synthesis" posted to blip.tv. 
> Previous versions of the class were called "Theory and Design of Music 
> Synthesizers" - I retitled the class to more clearly indicated the 
> increased analog focus and decreased digital focus of this version of 
> the class (but there's some random bits of DSP-ish stuff in there, like 
> discussions of aliasing).
> 
> There were 22 lectures this semester. Alas only 21 are posted, since I 
> had technical issues with the camera one day.
> 
> The website is: http://users.ece.gatech.edu/~lanterma/ems
> 
> Come enjoy the videos - and also try your hand at the homeworks if 
> you're looking for some fun. ;)
> 
Umm, maybe i'm blind or some, but apparently the blip.tv server doesn't 
know about the video of session 11 (the one AFTER the week without 
video...). Literally it says: "Sorry, this video has benn removed from 
blip.tv"

Greetings,
Florian



From seb at burnit.co.uk  Tue Apr 22 09:59:20 2008
From: seb at burnit.co.uk (Seb Francis)
Date: Tue, 22 Apr 2008 08:59:20 +0100
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <200804220103.m3M13Vii019226@sapphire.spiritone.com>
References: <200804220103.m3M13Vii019226@sapphire.spiritone.com>
Message-ID: <480D9AD8.30005@burnit.co.uk>

Akai S5000/6000 use normal FAT32 format.  Their SCSI implementation is 
pretty iffy but works well enough just to plug in a hard drive.  You can 
fit an internal hard drive (at least this is certainly true for the 
S6000) which saves messing around with external cases and power.  
Whichever way you do it you need an older SCSI hard drive.  50-pin 
SCSI-2 to be precise.  Sure to be some around on the second hand market.

Another option is an external SCSI ZIP drive which used to be pretty 
common (I might even have one somewhere .. ask if you're interested and 
I'll have a look).

Seb


>
>   
>> bill bigrig wrote:
>>     
>>>  Mainly, I want to know if i can take a SCSI device
>>> Akai 5000, or Roland VS-2480-cd, and use USB storage.
>>> Or is it better to try finding SCSI hard drives used?
>>> Can they be bought new? Not to mention the cable
>>> issue(large/small) I have a CD-ROM for the Akai 5000
>>> to run my Mellotron sounds. That's all I've done. but
>>> if I collect samples  and load them in, go to all the
>>> trouble of keyboard mapping sound effects etc. Can it
>>> be converted over to USB or should I just fish for
>>> SCSI drives and cables.
>>>   
>>>       
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>     
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>   




From louis at dompselaar.org  Tue Apr 22 10:04:58 2008
From: louis at dompselaar.org (Louis van Dompselaar)
Date: Tue, 22 Apr 2008 10:04:58 +0200
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <480D9AD8.30005@burnit.co.uk>
References: <200804220103.m3M13Vii019226@sapphire.spiritone.com>
	<480D9AD8.30005@burnit.co.uk>
Message-ID: <480D9C2A.8070307@dompselaar.org>

A third option (which I use in my S6000) is to use a SCSI-IDE converter 
and an IDE drive.  I have a 30GB internal IDE drive in mine.  Works 
great and doesn't get warm even with the fan at "low" setting.

> Akai S5000/6000 use normal FAT32 format.  Their SCSI implementation is 
> pretty iffy but works well enough just to plug in a hard drive.  You 
> can fit an internal hard drive (at least this is certainly true for 
> the S6000) which saves messing around with external cases and power.  
> Whichever way you do it you need an older SCSI hard drive.  50-pin 
> SCSI-2 to be precise.  Sure to be some around on the second hand market.
>
> Another option is an external SCSI ZIP drive which used to be pretty 
> common (I might even have one somewhere .. ask if you're interested 
> and I'll have a look). 



From cbergmiller at gmail.com  Tue Apr 22 10:13:16 2008
From: cbergmiller at gmail.com (Christian Bergmiller)
Date: Tue, 22 Apr 2008 10:13:16 +0200
Subject: [sdiy] LF357 Metal can
In-Reply-To: <20080420222126.GI59657@moo.sysabend.org>
References: <20080420222126.GI59657@moo.sysabend.org>
Message-ID: <8bb8f7150804220113u12f06800kdb0fa7ac5fbd7454@mail.gmail.com>

I may have some, will search for them this evening.
i'm in germany though..

christian

2008/4/21, Tom Arnold <xyzzy at sysabend.org>:
> By any chance does anyone have or know of a source for Metal can LF357s?   I
> thought I had some left but I only seem to have them in DIP and for this
> particular application ( rebuilding an old preamp ) I'd like to go with a
> metal can for it.
>
> I suppose in this application there are a ton of good substitutes like
> perhaps the OPA134 also in DIP so maybe I just shouldnt stress about it but I
> also havent popped the lid yet to see if the board was arranged for DIP or
> circular pinout.  Yeah, this might ring a bell for any Dynaco fans out
> there...
>
> --
>  -----------------------------------------------------------------
>  - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org
>  - SynthGeek        -
>  - BBD Fanatic      -  "...is it a virus, a drug, or a religion?"
>  - echo evho wjxo   -    Juanita Shrugs. "What's the difference?"
>  --------------------
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From colin at colinfraser.com  Tue Apr 22 10:14:19 2008
From: colin at colinfraser.com (Colin f)
Date: Tue, 22 Apr 2008 09:14:19 +0100
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <480D9C2A.8070307@dompselaar.org>
Message-ID: <000301c8a450$ddd21210$0101a8c0@zen2>

 
> A third option (which I use in my S6000) is to use a SCSI-IDE 
> converter 
> and an IDE drive.  I have a 30GB internal IDE drive in mine.  Works 
> great and doesn't get warm even with the fan at "low" setting.

Yeah, I've use one of these in my S6000:
http://www.span.com/catalog/product_info.php?products_id=1058&source=gbaseuk
&currency=GBP

The advantage of this adaptor is that it manages a much higher transfer
speed than the SCSI CF card reader.
Combined with an IDE to CF adaptor, you can add a non-hot-swappable CF drive
to your sampler.

Cheers,
Colin f




From colin at colinfraser.com  Tue Apr 22 10:19:35 2008
From: colin at colinfraser.com (Colin f)
Date: Tue, 22 Apr 2008 09:19:35 +0100
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <200804220103.m3M13Vii019226@sapphire.spiritone.com>
Message-ID: <000901c8a451$9a298e20$0101a8c0@zen2>

 
> Another issue I'd be curious about is formatting. A lot of 
> the samplers have their own disc format which is different 
> than what a PC or MAC uses.

That's true - I previously used a SCSI to IDE adaptor in an EMU ESI2000.
It wouldn't work going through the normal format procedure, as the SCSI'd
IDE drive wouldn't respond to a SCSI Format command.
But there was a hidden option in the ESI to 'write file system only',
without doing the format instruction.
That worked perfectly for both IDE drives and CF on the SCSI adaptor.
YMMV.

Cheers,
Colin f




From harrybissell at wowway.com  Tue Apr 22 16:11:12 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Tue, 22 Apr 2008 09:11:12 -0500
Subject: [sdiy] CMOS clock problem
In-Reply-To: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>
References: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>
Message-ID: <20080422140831.M86373@wowway.com>

Do you have a schematic ?

I'm assuming its the traditional two-gate oscillator with
one capacitor and two resistors.  One resistor and the cap
sets the frequency, the other resistor is in series with the
gate input to stop the input diodes from being too much of a pain
in the @ss.  The resistor to the input should be about 10x the size
of the frequency determining resistor.

It could be that loading stops it from starting... is the output
buffered ???

H^) harry



On Mon, 21 Apr 2008 16:44:43 -0400, mark verbos wrote
> Hi,
> 
> I have a high frequency clock made out of a couple 4001 gates in my  
> quantizer module. It doesn't like to start clocking when I turn it  
> on. Then I touch the pins with the scope probe and it starts going. 
> I  tried adding a 2.2M resistor to ground on the pin where the cap 
>  connects and I got it to start if I plug the connector in while the 
>  cabinet is powered up, but if I power cycle it while plugged in 
> it's  not oscillating. Is this something to do with the order that 
> the  power rails are coming up? It's only using +15 and GND, so I 
> don't  see how it could.
> 
> Any ideas? I'm lost.
> 
> Mark
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From Barry.L.Klein at wdc.com  Tue Apr 22 19:14:56 2008
From: Barry.L.Klein at wdc.com (Barry Klein)
Date: Tue, 22 Apr 2008 10:14:56 -0700
Subject: [sdiy] Bent 2008?
In-Reply-To: <480D3602.203@eventualdecline.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
	<480D3602.203@eventualdecline.com>
Message-ID: <6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>

Anyone attend one of these recently?
Thoughts?



From subjectivity at hotmail.com  Tue Apr 22 20:14:50 2008
From: subjectivity at hotmail.com (Dan Snazelle)
Date: Tue, 22 Apr 2008 18:14:50 +0000
Subject: [sdiy] Bent 2008?
In-Reply-To: <6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
	<480D3602.203@eventualdecline.com>
	<6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
Message-ID: <BAY144-W77701005EFB936452AC19C8E00@phx.gbl>


I will be going for sure, if for nothing else than the chance to meet some synth and noise freaks!
there are some free workshos going on as well, which look great.

If any other NY'ers are going from SDIY, it would be great to try to meet up and have a SDIY lunch or something.





--------------------------------------------
check out various dan music at:

http://www.myspace.com/lossnyc


http://www.soundclick.com/lossnyc.htm


http://www.indie911.com/dan-snazelle
(or for techno) http://www.myspace.com/snazelle





From dalenkarl at yahoo.se  Tue Apr 22 22:12:44 2008
From: dalenkarl at yahoo.se (karl dalen)
Date: Tue, 22 Apr 2008 22:12:44 +0200 (CEST)
Subject: SV: Re: SV: Re: [sdiy] Any LM331 experts around?
In-Reply-To: <480C2860.1000300@sonic.net>
Message-ID: <106901.91701.qm@web27604.mail.ukl.yahoo.com>

AN14........5,5MB!
But it's one of best/better VFC papers available.

KD

--- Dave Manley <dlmanley at sonic.net> skrev:

> >   
> Hi Karl,
> 
> Do you have an app note number (ANxxxx) or a lnk?
> 
> Thanks,
> Dave




      __________________________________________________________
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S?k och j?mf?r hos Yahoo! Shopping.
http://shopping.yahoo.se/c-100015813-bredband.html?partnerId=96914325




From drheqx at heqx.com  Tue Apr 22 23:22:38 2008
From: drheqx at heqx.com (DrHeqx)
Date: Tue, 22 Apr 2008 17:22:38 -0400
Subject: [sdiy] Bent 2008?
References: <973734.22441.qm@web32705.mail.mud.yahoo.com><480D3602.203@eventualdecline.com>
	<6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
	<BAY144-W77701005EFB936452AC19C8E00@phx.gbl>
Message-ID: <000c01c8a4be$fee6cfe0$29140a0a@Speedy>

hey guys what day(s) are you going? I will be there. It's just one of those 
things that adds a certain spice to your life. How will we meet amongst all 
the people there?

( from West Hills, NY )

heqx


>
> I will be going for sure, if for nothing else than the chance to meet some 
> synth and noise freaks!
> there are some free workshos going on as well, which look great.
>
> If any other NY'ers are going from SDIY, it would be great to try to meet 
> up and have a SDIY lunch or something.
>
>
>
>
>
> --------------------------------------------
> check out various dan music at:
>
> http://www.myspace.com/lossnyc
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From Barry.L.Klein at wdc.com  Wed Apr 23 00:33:54 2008
From: Barry.L.Klein at wdc.com (Barry Klein)
Date: Tue, 22 Apr 2008 15:33:54 -0700
Subject: [sdiy] Bent 2008?
In-Reply-To: <000c01c8a4be$fee6cfe0$29140a0a@Speedy>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com><480D3602.203@eventualdecline.com>
	<6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
	<BAY144-W77701005EFB936452AC19C8E00@phx.gbl>
	<000c01c8a4be$fee6cfe0$29140a0a@Speedy>
Message-ID: <6B16794FD98610449F66759BBF503D40CEDF9D@wdscexbe03.sc.wdc.com>

The one in LA just happened.  No one went?


-----Original Message-----
From: DrHeqx [mailto:drheqx at heqx.com] 
Sent: Tuesday, April 22, 2008 2:23 PM
To: Dan Snazelle; Barry Klein; Synth DIY
Subject: Re: [sdiy] Bent 2008?

hey guys what day(s) are you going? I will be there. It's just one of those 
things that adds a certain spice to your life. How will we meet amongst all 
the people there?

( from West Hills, NY )

heqx


>
> I will be going for sure, if for nothing else than the chance to meet some

> synth and noise freaks!
> there are some free workshos going on as well, which look great.
>
> If any other NY'ers are going from SDIY, it would be great to try to meet 
> up and have a SDIY lunch or something.
>
>
>
>
>
> --------------------------------------------
> check out various dan music at:
>
> http://www.myspace.com/lossnyc
>
>
> http://www.soundclick.com/lossnyc.htm
>
>
> http://www.indie911.com/dan-snazelle
> (or for techno) http://www.myspace.com/snazelle
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 





From pschreiber at sbcglobal.net  Wed Apr 23 03:37:00 2008
From: pschreiber at sbcglobal.net (Paul Schreiber)
Date: Tue, 22 Apr 2008 20:37:00 -0500
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
	tomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
Message-ID: <008201c8a4e2$87151890$b000a8c0@curley>

Jeez, I designed this thing in 1980 and it won't die :)

Paul S.

----- Original Message ----- 
From: "anthony" <aankrom at bluemarble.net>
To: <Synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 21, 2008 1:13 PM
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge 
tomodify...


> Hi guys,
>
> So I have one Realistic Electronic Reverb: the greatest effect to use for 
> not quite what it was intended for. This booger is a great noisemaker and 
> lots of fun with it's slider controls. It's even better with a few tweaks 
> to the circuit: more gain and high-end roll-off to the regen path, 471pF 
> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place 
> of the AN6550's, socket for the timing cap to play with different values, 
> adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've thought 
> about wiring 2 or 3 in series, the BL3208A being something like $3.75 in 
> price. Next planned mod is making the "DEPTH" control into a true wet/dry 
> crossfader, which is a non-trivial task, but not impossible: I think a 1 
> uf cap and a couple 100kOhm resistors to put the bias in the right place 
> again and cutting the traces on the PCB and rewiring accordingly.
>
> SO I've been trying to buy another one on eBay for what I got my first one 
> for ($12.00) and it's been a daunting task. People are catching on to how 
> cool these are.
>
> I'm not one to care much for collectability in gear because I like to be 
> able to use my gear to the fullest. But I'm planning some more mods that 
> will actuall involve cutting into the unit and I'm beginning to wonder 
> whether I should. I wanted to add a DP3T selector switch to select between 
> various timing caps (if I can just find a good place on the front for a 
> toggle switch to go...), and adding some brass body contacts to bring it 
> (sort of) into the realm of circuit bending. I must admit that I don't 
> actually hold to the philosphy of circuit bending although I enjoy hearing 
> some of the results. I don't think wiring various contacts and capacitors 
> to the timing cap connections could be considered circuit bending in its 
> true spirit because they are not random bends, but carefully thought out 
> connections. Putting your fingers across the timing cap terminals is very 
> fun: it depends on the pressure exerted so it has a playability factor to 
> it: you can quickly (or slowly) descend into the realm of 2 second delays 
> and back again. With the increased number of stages in the BL3208A, it's 
> even better: repeats just go on and on without sounding like an 
> oscillation, but it'll oscillate too - and how!
>
> So I'm wondering: should I do it? I mean even when they're going at $40 on 
> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
> something.
>
> Also, if anyone has DONE the wet/dry crossfade mod and would like to 
> share, I'd appreciate that a lot. Thanx...
>
>
> Cheers,
> Anthony
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 



From jdec at mindspring.com  Wed Apr 23 03:58:22 2008
From: jdec at mindspring.com (BrightBoy)
Date: Tue, 22 Apr 2008 21:58:22 -0400 (GMT-04:00)
Subject: [sdiy] Rising Realsitic Electronic Reverb prices and the urge
	to modify...
Message-ID: <2198741.1208915902789.JavaMail.root@mswamui-chipeau.atl.sa.earthlink.net>

Did you also design the Radio Shack Stereo Synthesizer unit?

Cheers,

Jeff

-----Original Message-----
>From: Paul Schreiber <pschreiber at sbcglobal.net>
>Sent: Apr 22, 2008 9:37 PM
>To: anthony <aankrom at bluemarble.net>, Synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge	tomodify...
>
>Jeez, I designed this thing in 1980 and it won't die :)
>
>Paul S.
>
>----- Original Message ----- 
>From: "anthony" <aankrom at bluemarble.net>
>To: <Synth-diy at dropmix.xs4all.nl>
>Sent: Monday, April 21, 2008 1:13 PM
>Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge 
>tomodify...
>
>
>> Hi guys,
>>
>> So I have one Realistic Electronic Reverb: the greatest effect to use for 
>> not quite what it was intended for. This booger is a great noisemaker and 
>> lots of fun with it's slider controls. It's even better with a few tweaks 
>> to the circuit: more gain and high-end roll-off to the regen path, 471pF 
>> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place 
>> of the AN6550's, socket for the timing cap to play with different values, 
>> adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
>> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've thought 
>> about wiring 2 or 3 in series, the BL3208A being something like $3.75 in 
>> price. Next planned mod is making the "DEPTH" control into a true wet/dry 
>> crossfader, which is a non-trivial task, but not impossible: I think a 1 
>> uf cap and a couple 100kOhm resistors to put the bias in the right place 
>> again and cutting the traces on the PCB and rewiring accordingly.
>>
>> SO I've been trying to buy another one on eBay for what I got my first one 
>> for ($12.00) and it's been a daunting task. People are catching on to how 
>> cool these are.
>>
>> I'm not one to care much for collectability in gear because I like to be 
>> able to use my gear to the fullest. But I'm planning some more mods that 
>> will actuall involve cutting into the unit and I'm beginning to wonder 
>> whether I should. I wanted to add a DP3T selector switch to select between 
>> various timing caps (if I can just find a good place on the front for a 
>> toggle switch to go...), and adding some brass body contacts to bring it 
>> (sort of) into the realm of circuit bending. I must admit that I don't 
>> actually hold to the philosphy of circuit bending although I enjoy hearing 
>> some of the results. I don't think wiring various contacts and capacitors 
>> to the timing cap connections could be considered circuit bending in its 
>> true spirit because they are not random bends, but carefully thought out 
>> connections. Putting your fingers across the timing cap terminals is very 
>> fun: it depends on the pressure exerted so it has a playability factor to 
>> it: you can quickly (or slowly) descend into the realm of 2 second delays 
>> and back again. With the increased number of stages in the BL3208A, it's 
>> even better: repeats just go on and on without sounding like an 
>> oscillation, but it'll oscillate too - and how!
>>
>> So I'm wondering: should I do it? I mean even when they're going at $40 on 
>> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
>> something.
>>
>> Also, if anyone has DONE the wet/dry crossfade mod and would like to 
>> share, I'd appreciate that a lot. Thanx...
>>
>>
>> Cheers,
>> Anthony
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy 
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy





From blincoln at eventualdecline.com  Wed Apr 23 04:19:44 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Tue, 22 Apr 2008 19:19:44 -0700
Subject: [sdiy] USB,SCSI,MIDI
In-Reply-To: <000901c8a451$9a298e20$0101a8c0@zen2>
References: <000901c8a451$9a298e20$0101a8c0@zen2>
Message-ID: <480E9CC0.8010603@eventualdecline.com>

Colin f wrote:
> That's true - I previously used a SCSI to IDE adaptor in an EMU ESI2000.
> It wouldn't work going through the normal format procedure, as the SCSI'd
> IDE drive wouldn't respond to a SCSI Format command.
> But there was a hidden option in the ESI to 'write file system only',
> without doing the format instruction.
> That worked perfectly for both IDE drives and CF on the SCSI adaptor.
> YMMV.
>   
If there is a particularly beloved model or two of device that uses a 
proprietary format and also won't cooperate with an adapted IDE drive or 
CF card, I would think the best approach would again be similar to what 
some console hackers have done: get an actual SCSI drive formatted for 
the device, connect it to a PC, and use a disk imaging tool to copy the 
raw data from it to as many IDE drives or CF cards as you like.
I don't know if any off-the-shelf imaging software (e.g. Ghost) can 
write an arbitrary image to a CF card (my reverse-engineering to date 
has been limited to binary files, not raw bits on physical media), but 
maybe dd on Linux would work?
I believe the Xbox hackers actually ended up taking a disk image and 
reverse-engineering it to the point that they could write a formatting 
utility which would allow them to use new drives of arbitrary sizes, 
although I may be thinking of a different platform. For disk formats 
from the 80s and 90s, I think this should be pretty easy since space 
efficiency was more important than obfuscating the format.


From batzman-nr at all-electric.com  Wed Apr 23 04:26:05 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Wed, 23 Apr 2008 11:56:05 +0930
Subject: [sdiy] Microchip PSG - AY8930
In-Reply-To: <17035a3d0804212214m40011c00j956c54b408504984@mail.gmail.co
 m>
Message-ID: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>

Y-ellow Loscha 'n' all.

At 03:14 PM 4/22/2008 +1000, Loscha wrote:
>At the time of writing, Rockby Electronics in Clayton, Melbourne,
>Australia have 30 of these in stock, at $5 a piece.
>
>Does anyone use these anymore?
>
>http://www.rockby.com.au/catresults.cfm?stock_no=22570&imageField2.x=0&imageField2.y=0

Yeah. I saw these too. Couldn't find a data sheet. What's the difference 
between these and the AY8910? If it's just a beefed up version of the 8910 
then it's probably not worth it.

But in any case, Alina's new count-down timer will probably run out before 
I find out they're worth something. Ah well.

Be absolutely icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From blincoln at eventualdecline.com  Wed Apr 23 06:13:03 2008
From: blincoln at eventualdecline.com (Ben Lincoln)
Date: Tue, 22 Apr 2008 21:13:03 -0700
Subject: [sdiy] Microchip PSG - AY8930
In-Reply-To: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>
References: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>
Message-ID: <480EB74F.3040209@eventualdecline.com>

Batz Goodfortune wrote:
> Yeah. I saw these too. Couldn't find a data sheet. What's the 
> difference between these and the AY8910? If it's just a beefed up 
> version of the 8910 then it's probably not worth it.
>
A datasheet like this one?

http://www.datasheet4u.com/html/A/Y/8/AY8930_MicrochipTechnology.pdf.html

It does look a lot like the other chips in the series (at least 
superficially?). I got a bunch of AY-3-8913 chips in grab bags from 
Jameco (so 10-15 cents each or thereabouts). I'd like to build a couple 
of little synths around them eventually, but given the simple 
architecture it seems like a lot more effort than some of the 
alternatives. I mostly like the idea of using an actual vintage 80s game 
console-type chip, and I figure it would be good practice doing reads 
and writes from registers, which I've done in assembly but not hardware.

If anyone is interested, but not $5 each interested, I got mine in 
Jameco's small analogue/linear grab bag the first time and many more in 
a large version of the same grab bag a month or two after that.


From harrybissell at wowway.com  Wed Apr 23 16:30:20 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Wed, 23 Apr 2008 09:30:20 -0500
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
	tomodify...
In-Reply-To: <008201c8a4e2$87151890$b000a8c0@curley>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
	<008201c8a4e2$87151890$b000a8c0@curley>
Message-ID: <20080423142712.M26886@wowway.com>

Its funny to me how products that I thought, well... er...
well it HAS got a BBD in it (if you catch my drift)...

were not too viable, have become loved and wanted. Its not just the
RatShack electronic reverb (which I did buy and build)... but also
EH Electric Mistress (which I did NOT buy as I thought it sucked..)

I guess there is no accounting for taste. If you love 'lo-fi' the
Radio Shack reverb has it in spades...

H^) harry





On Tue, 22 Apr 2008 20:37:00 -0500, Paul Schreiber wrote
> Jeez, I designed this thing in 1980 and it won't die :)
> 
> Paul S.
> 
> ----- Original Message ----- 
> From: "anthony" <aankrom at bluemarble.net>
> To: <Synth-diy at dropmix.xs4all.nl>
> Sent: Monday, April 21, 2008 1:13 PM
> Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the 
> urge tomodify...
> 
> > Hi guys,
> >
> > So I have one Realistic Electronic Reverb: the greatest effect to use for 
> > not quite what it was intended for. This booger is a great noisemaker and 
> > lots of fun with it's slider controls. It's even better with a few tweaks 
> > to the circuit: more gain and high-end roll-off to the regen path, 471pF 
> > polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place 
> > of the AN6550's, socket for the timing cap to play with different values, 
> > adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
> > popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've thought 
> > about wiring 2 or 3 in series, the BL3208A being something like $3.75 in 
> > price. Next planned mod is making the "DEPTH" control into a true wet/dry 
> > crossfader, which is a non-trivial task, but not impossible: I think a 1 
> > uf cap and a couple 100kOhm resistors to put the bias in the right place 
> > again and cutting the traces on the PCB and rewiring accordingly.
> >
> > SO I've been trying to buy another one on eBay for what I got my first one 
> > for ($12.00) and it's been a daunting task. People are catching on to how 
> > cool these are.
> >
> > I'm not one to care much for collectability in gear because I like to be 
> > able to use my gear to the fullest. But I'm planning some more mods that 
> > will actuall involve cutting into the unit and I'm beginning to wonder 
> > whether I should. I wanted to add a DP3T selector switch to select between 
> > various timing caps (if I can just find a good place on the front for a 
> > toggle switch to go...), and adding some brass body contacts to bring it 
> > (sort of) into the realm of circuit bending. I must admit that I don't 
> > actually hold to the philosphy of circuit bending although I enjoy hearing 
> > some of the results. I don't think wiring various contacts and capacitors 
> > to the timing cap connections could be considered circuit bending in its 
> > true spirit because they are not random bends, but carefully thought out 
> > connections. Putting your fingers across the timing cap terminals is very 
> > fun: it depends on the pressure exerted so it has a playability factor to 
> > it: you can quickly (or slowly) descend into the realm of 2 second delays 
> > and back again. With the increased number of stages in the BL3208A, it's 
> > even better: repeats just go on and on without sounding like an 
> > oscillation, but it'll oscillate too - and how!
> >
> > So I'm wondering: should I do it? I mean even when they're going at $40 on 
> > eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
> > something.
> >
> > Also, if anyone has DONE the wet/dry crossfade mod and would like to 
> > share, I'd appreciate that a lot. Thanx...
> >
> >
> > Cheers,
> > Anthony
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From synth at casperelectronics.com  Wed Apr 23 19:31:56 2008
From: synth at casperelectronics.com (peter edwards)
Date: Wed, 23 Apr 2008 13:31:56 -0400
Subject: [sdiy] Bent 2008?
In-Reply-To: <6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com>
	<480D3602.203@eventualdecline.com>
	<6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
Message-ID: <11DC838E-BB1F-4559-8153-DC8459758E41@casperelectronics.com>

I've been involved with Bent for the past 5 years. It's a pretty fun  
event and there are some really great workshops. The work at the  
fests (that people bring and install) ranges from embarrassing to  
incredible. I've seen some really inspiring work. I'd say that the  
extreme variety is one of the selling points of the fest. The  
performances are usually on the noisy side but there is also a huge  
amount of variety. Some of the best and worst acts I've seen have  
been at bent.
I just got back from the LA fest and I'm busy getting ready for the  
NY one. LA was pretty low key but consistently high quality. I'm  
really glad I went.

I'll be setting up a booth at the NY fest. Showing off my new  
"product", giving out stickers and selling some merch. I'm also doing  
a raffle for a modified SPeak&Spell.
I'll be at the CASPERELECTRONICS table. I look forward to meeting  
other sdiy guys.... so make sure and stop by and say hi.
-pete

On Apr 22, 2008, at 1:14 PM, Barry Klein wrote:

> Anyone attend one of these recently?
> Thoughts?
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From Barry.L.Klein at wdc.com  Wed Apr 23 20:05:35 2008
From: Barry.L.Klein at wdc.com (Barry Klein)
Date: Wed, 23 Apr 2008 11:05:35 -0700
Subject: [sdiy] Bent 2008?
In-Reply-To: <11DC838E-BB1F-4559-8153-DC8459758E41@casperelectronics.com>
References: <973734.22441.qm@web32705.mail.mud.yahoo.com><480D3602.203@eventualdecline.com><6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
	<11DC838E-BB1F-4559-8153-DC8459758E41@casperelectronics.com>
Message-ID: <6B16794FD98610449F66759BBF503D40CEDFA2@wdscexbe03.sc.wdc.com>

Will you be at Makerfaire too (couple weeks)?
I will be there Saturday.

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of peter edwards
Sent: Wednesday, April 23, 2008 10:32 AM
To: Synth DIY
Subject: Re: [sdiy] Bent 2008?

I've been involved with Bent for the past 5 years. It's a pretty fun  
event and there are some really great workshops. The work at the  
fests (that people bring and install) ranges from embarrassing to  
incredible. I've seen some really inspiring work. I'd say that the  
extreme variety is one of the selling points of the fest. The  
performances are usually on the noisy side but there is also a huge  
amount of variety. Some of the best and worst acts I've seen have  
been at bent.
I just got back from the LA fest and I'm busy getting ready for the  
NY one. LA was pretty low key but consistently high quality. I'm  
really glad I went.

I'll be setting up a booth at the NY fest. Showing off my new  
"product", giving out stickers and selling some merch. I'm also doing  
a raffle for a modified SPeak&Spell.
I'll be at the CASPERELECTRONICS table. I look forward to meeting  
other sdiy guys.... so make sure and stop by and say hi.
-pete

On Apr 22, 2008, at 1:14 PM, Barry Klein wrote:

> Anyone attend one of these recently?
> Thoughts?
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From adam.troyer at gatech.edu  Wed Apr 23 20:13:04 2008
From: adam.troyer at gatech.edu (Adam Troyer)
Date: Wed, 23 Apr 2008 14:13:04 -0400
Subject: [sdiy] Oscillator Help
Message-ID: <480F7C30.6050106@gatech.edu>

Hello everyone!
I'm a student in Aaron Lanterman's 'Electronics for Music Synthesis' 
class at Georgia Tech, and I'm having
some problems with the oscillator I'm building for our final project.  
He suggested that this would be the place
to go for some help, so here I am!

My design is on page 4 of this pdf: 
http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/comparator/lm392_apnote.pdf,
the 'Exponential V/F Converter for Electronic Music'.

There are two main issues I'm having at the moment.  The first issue is 
with the resistor and 5k pot on the left side
of the schematic.  The resistor on the left doesn't have a value, so 
I've been assuming that the text on the right of
the pot (the '4.7k* select...') was referring to that resistor.  Does 
this seem right?

The second issue is a little more complicated.  When testing the circuit 
yesterday, I was getting some oscillations at the
output pin of C1.  With the 5k 'Zero' pot turned all the way toward the 
input, I would get a short time of about 0 voltage
followed by a long time of constant voltage at this pin (it looked a lot 
like waveform A on page 5, since I'm not describing
it very well).  When I turned the pot away from the input, the 
oscillations would increase in frequency some, but if I turned
the pot too far the voltage at the pin would drop down to nearly 0V and 
stay that way, and wouldn't oscillate again even
if I turned the pot back.  I actually had to turn the circuit's power 
supply off and wait a little while before turning it back on
to get the oscillations to start back up.  Even with the oscillations at 
this pin, though, I wasn't getting any response at the
inverting input of C1.

If anyone has any insight into what's going on with this circuit, it'd 
be greatly appreciated.  I understand the basics of how
it's supposed to work (except for the temperature compensating stuff at 
the bottom of the schematic, that's beyond me),
but I can't figure out what the problem is.  Thanks in advance for your 
help!

-Adam Troyer


From mr at analogue.org  Wed Apr 23 21:11:31 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Wed, 23 Apr 2008 21:11:31 +0200
Subject: [sdiy] Pots, cermet vs conductive plastic
Message-ID: <200804231911.m3NJB4vB012731@dropmix.xs4all.nl>

At 06:17 2005-10-03, Paul Schreiber wrote:

>I am a firm believer of "you get what you pay for".
>[...]
>However, for the VCOs I wanted cermet pots for minimal drifting 
>(even though used ratiometrically cermet drifts 100X less than 
>carbon) and wanted conductive plastic (super long life) for the others.

So, a cermet pot changes its total resistance less than a conductive 
plastic pot when the temperature changes.

But if you connect it (ratiometrically) between two known voltages 
and just pick out a voltage in between, is there any difference 
between cermet and CP?
(In other words; is there really a need for cermet in VCO tuning dials?)

Other potential (sic!) differences:
The 'feel' when turning  -  does the material matter?
The 'precision', when it comes to setting the pot to 'any position'?
The 'mechanical drift'  -  does the wiper stay in the exact same place?
After a long time of no use  -  is one of them less scratchy?


/mr 




From mr at analogue.org  Wed Apr 23 21:13:20 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Wed, 23 Apr 2008 21:13:20 +0200
Subject: [sdiy] Switches, NKK vs everybody else :-)
Message-ID: <200804231912.m3NJCVWg012742@dropmix.xs4all.nl>

At 06:17 2005-10-03, Paul Schreiber wrote:

>I am a firm believer of "you get what you pay for".
>[...]
>Switches: NKK is it. All others are crap. The Mouser 'Mountain' 
>switches are to be avoided at all costs. C&K has *long-term* 
>reliability issues (likes to break in 3 years). I've *never* seen a 
>NKK switch failure in 27 years of using them. I used 6 *million* of 
>them at Tandy. They just make a fine pruduct.

Are all NKK models reliable, or are some series the ones to choose?

The panel-mounted 'M' miniature series seems quite common.
         http://www.nkkswitches.com/series.aspx?stid=1&id=4
Is this the one used in MOTM, for instance?

Personally I'm a big fan of switches with flatted toggles. Sadly they 
always seem either scarce or expensive... so even these half-an-Euro 
dirt cheap Taiwanese ones make me drool:

   http://banzaieffects.com/Low-Cost-FT-SPDT-on-off-on-pr-24829.html
   http://banzaieffects.com/Low-Cost-FT-DPDT-on-on-pr-24831.html

These are even Dual(!) Pole, so you could wire them in parallel for 
lower risk of failure. They can't be so low-quality that they are not 
worth their low price... can they? :-)


/mr 




From jhaible at debitel.net  Wed Apr 23 22:05:54 2008
From: jhaible at debitel.net (JH.)
Date: Wed, 23 Apr 2008 22:05:54 +0200
Subject: [sdiy] Pots, cermet vs conductive plastic
References: <200804231911.m3NJB4vB012731@dropmix.xs4all.nl>
Message-ID: <04c701c8a57d$709f9220$0400a8c0@jhsilent>

>So, a cermet pot changes its total resistance less than a conductive
>plastic pot when the temperature changes.
>
>But if you connect it (ratiometrically) between two known voltages
>and just pick out a voltage in between, is there any difference
>between cermet and CP?

Depends on the load, i.e. on the resistor value from the pot's wiper to the 
virtual GND summing node, compared to the pot's own value.
The pot and the resistor will not have the same tempco, so there will be 
some temperature drift. High value for resitor and low value for pot will 
reduce this effect.

JH. 



From ijfritz at comcast.net  Wed Apr 23 22:45:47 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 23 Apr 2008 14:45:47 -0600
Subject: [sdiy] Oscillator Help
In-Reply-To: <480F7C30.6050106@gatech.edu>
References: <480F7C30.6050106@gatech.edu>
Message-ID: <6.2.1.2.2.20080423142155.021d5e38@mail.comcast.net>

At 12:13 PM 4/23/2008, Adam Troyer wrote:
>Hello everyone!

Hi Adam!

>My design is on page 4 of this pdf: 
>http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/comparator/lm392_apnote.pdf,
>the 'Exponential V/F Converter for Electronic Music'.
>
>There are two main issues I'm having at the moment.  The first issue is 
>with the resistor and 5k pot on the left side
>of the schematic.  The resistor on the left doesn't have a value, so I've 
>been assuming that the text on the right of
>the pot (the '4.7k* select...') was referring to that resistor.  Does this 
>seem right?

Yeah, that circuit is hard enough to understand without having the labeling 
screwed up.

So for a sanity check, let's do a real rough ballpark estimate of what the 
mystery R should be.  You can do some little calculations to verify the 
following:

1.) We are told in the text that the 2uF cap has a signal level of 
~12mV.  Therefore the charge transfered each cycle is ~24nC.

2.) Let's assume that the oscillator will run up to 40kHz without 
saturating Q1.  (It's accurate up to 20kHz, so it should run higher than 
that.)  At 40kHz the current through Q1 is ~1mA.

3.) If the Vcb of Q1 is greater than zero (at 40 kHz) then the unlabeled R 
is less than 7k.

So 4.7k seems plausible. They say to select it, because its value depends 
on the reverse leakage current Is of the transistor, which can vary quite a 
bit between parts.


>The second issue is a little more complicated.  When testing the circuit 
>yesterday, I was getting some oscillations at the
>output pin of C1.  With the 5k 'Zero' pot turned all the way toward the 
>input, I would get a short time of about 0 voltage
>followed by a long time of constant voltage at this pin (it looked a lot 
>like waveform A on page 5, since I'm not describing
>it very well).

OK, that means it's oscillating.  You should be able to determine the 
frequency by measuring the time between the pulses.

>When I turned the pot away from the input, the oscillations would increase 
>in frequency some, but if I turned
>the pot too far the voltage at the pin would drop down to nearly 0V and 
>stay that way, and wouldn't oscillate again even
>if I turned the pot back.  I actually had to turn the circuit's power 
>supply off and wait a little while before turning it back on
>to get the oscillations to start back up.

It looks to me like if you set that resistance too small you could be 
pushing Q1 too far into forward bias.  Keep away from the end of the pot, 
or put a 2k fixed resistor in series with it.

>Even with the oscillations at this pin, though, I wasn't getting any 
>response at the
>inverting input of C1.

Impossible!  It's a very small signal, so you need to turn your scope 
sensitivity way up.

Sounds to me like its working! :-)

   Ian



From drheqx at heqx.com  Thu Apr 24 00:05:53 2008
From: drheqx at heqx.com (DrHeqx)
Date: Wed, 23 Apr 2008 18:05:53 -0400
Subject: [sdiy] Bent 2008?
References: <973734.22441.qm@web32705.mail.mud.yahoo.com><480D3602.203@eventualdecline.com><6B16794FD98610449F66759BBF503D40CEDF99@wdscexbe03.sc.wdc.com>
	<11DC838E-BB1F-4559-8153-DC8459758E41@casperelectronics.com>
Message-ID: <000e01c8a58e$33f173a0$29140a0a@Speedy>

Pete,
I am going on Saturday. I'll look for you.

Barry, hope to see you there as well.

heqx

> I've been involved with Bent for the past 5 years. It's a pretty fun  
> event and there are some really great workshops. The work at the  
> fests (that people bring and install) ranges from embarrassing to  
> incredible. I've seen some really inspiring work. I'd say that the  
> extreme variety is one of the selling points of the fest. The  
> performances are usually on the noisy side but there is also a huge  
> amount of variety. Some of the best and worst acts I've seen have  
> been at bent.
> I just got back from the LA fest and I'm busy getting ready for the  
> NY one. LA was pretty low key but consistently high quality. I'm  
> really glad I went.
> 
> I'll be setting up a booth at the NY fest. Showing off my new  
> "product", giving out stickers and selling some merch. I'm also doing  
> a raffle for a modified SPeak&Spell.
> I'll be at the CASPERELECTRONICS table. I look forward to meeting  
> other sdiy guys.... so make sure and stop by and say hi.
> -pete

>


From mr at analogue.org  Thu Apr 24 00:16:20 2008
From: mr at analogue.org (Mattias Rickardsson)
Date: Thu, 24 Apr 2008 00:16:20 +0200
Subject: [sdiy] Pots, cermet vs conductive plastic
In-Reply-To: <04c701c8a57d$709f9220$0400a8c0@jhsilent>
References: <200804231911.m3NJB4vB012731@dropmix.xs4all.nl>
	<04c701c8a57d$709f9220$0400a8c0@jhsilent>
Message-ID: <1f4a82040804231516p4a4ea3ewbf40ddc8ededa220@mail.gmail.com>

On 23/04/2008, JH. <jhaible at debitel.net> wrote:
> >So, a cermet pot changes its total resistance less than a conductive
>  >plastic pot when the temperature changes.
>  >But if you connect it (ratiometrically) between two known voltages
>  >and just pick out a voltage in between, is there any difference
>  >between cermet and CP?
>
> Depends on the load, i.e. on the resistor value from the pot's wiper to the
>  virtual GND summing node, compared to the pot's own value.
>  The pot and the resistor will not have the same tempco, so there will be
>  some temperature drift. High value for resitor and low value for pot will
>  reduce this effect.

Yes, but if the load is neglected... if you really just pick out a voltage...
A potentiometer is never perfect in the way its resistance varies over
the shaft angles, for example. Is there anything that could result in
temperature differences?


/mr


From lanterma at ece.gatech.edu  Thu Apr 24 18:58:06 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Thu, 24 Apr 2008 12:58:06 -0400
Subject: [sdiy] Alternate VCO circuit in case you can't get that other one
	working
In-Reply-To: <480F7C30.6050106@gatech.edu>
References: <480F7C30.6050106@gatech.edu>
Message-ID: <B5FB903D-607D-4E41-8589-D30C2D5CCDBB@ece.gatech.edu>

Dear Adam,

Here's another oscillator that uses the a CA3046 - but I think this  
one might be easier to make go, because there aren't any weird pots to  
tweak that might make things stop. Note it uses the same idea of  
keeping the CA3046 at a constant temperature. It also uses a 2N2907A,  
and you should be able to get 2N2222 from the stockroom (if not  
already in one of the labs, it's a very common transistor):

http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/AN-299.pdf

See Figure 1.

If nothing else, I think I understand this one much better. Read this  
writeup, I think you will too. It also has a hell of a lot less diodes.

Sorry I meant to send this to you sooner, but it took me a long time  
to find it. I'd seen it somewhere but couldn't remember where.

This design is similar to the Korg MS-20 - the two transistors at the  
top form something weird called a "thyristor."

Instead of the LF412, you could try an TL082 or LF353 (I have some  
353s in the bins).

- Aaron


From jpdesroc at oricom.ca  Thu Apr 24 19:02:38 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Thu, 24 Apr 2008 13:02:38 -0400
Subject: [sdiy] COSMO knobs type 7603 for sale??
Message-ID: <380-22008442417238967@oricom.ca>

Hi list,
Does anybody have COSMO knobs type 7603 (not 7602)
like the Moog 921B VCO module 'Frequency' control
see picture http://www.siliconbreakdown.com/moog55.html
for sale? They have 1.25" base diameter.
I'd need 15 of them.
Please email me at jpdesroc at oricom.ca
Thanks




From lanterma at ece.gatech.edu  Thu Apr 24 19:03:40 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Thu, 24 Apr 2008 13:03:40 -0400
Subject: [sdiy] Odd OTA behavior
Message-ID: <81B95CAC-AF8E-4BBE-885D-0EE37D71C01A@ece.gatech.edu>

I just got this e-mail from a student:

>  I took the remaining 13700 and the 082 I was using and tried them  
> on another board and found that the 13700 wouldn't keep a steady  
> ~-13-14V at the Icon terminal - placing a resistor between +15 and  
> the terminal (trying with 520kOhm) would rise the voltage at Icon to  
> ~1.4V.

I thought the voltage at a control pin of an OTA typically hung out a  
diode drop or two above the negative rail. What could he have done to  
make it measure at 1.4?

(I'm thinking he probably hosed the chip somewhere along the line -  
blowing up a 13700 seems to be a rite of passage in my class; either  
that or he's flat out screwing up the measurement somehow.)

- Aaron



From lanterma at ece.gatech.edu  Thu Apr 24 19:15:03 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Thu, 24 Apr 2008 13:15:03 -0400
Subject: [sdiy] Alternate VCO circuit <- meant to go to student, not list
In-Reply-To: <B5FB903D-607D-4E41-8589-D30C2D5CCDBB@ece.gatech.edu>
References: <480F7C30.6050106@gatech.edu>
	<B5FB903D-607D-4E41-8589-D30C2D5CCDBB@ece.gatech.edu>
Message-ID: <785A8111-3380-4E5E-A808-8313F9BEBE94@ece.gatech.edu>


On Apr 24, 2008, at 12:58 PM, Aaron Lanterman wrote:

> Dear Adam,
>
> Here's another oscillator that uses the a CA3046 - but I think this  
> one might be easier to make go, because there aren't any weird pots  
> to tweak that might make things stop. Note it uses the same idea of  
> keeping the CA3046 at a constant temperature. It also uses a  
> 2N2907A, and you should be able to get 2N2222 from the stockroom (if  
> not already in one of the labs, it's a very common transistor):

Whoops - sorry I meant for that to go just to Adam... sorry to clutter  
up the list!

- Aaron


From mirwin at marketbridge.ca  Thu Apr 24 20:12:26 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Thu, 24 Apr 2008 14:12:26 -0400
Subject: [sdiy] Odd OTA behavior
References: <81B95CAC-AF8E-4BBE-885D-0EE37D71C01A@ece.gatech.edu>
Message-ID: <004401c8a636$c1449040$c3dc47d1@ca>

Maybe the V(-) supply pin of the OTA is connected to ground instead of  V(-)
?



----- Original Message -----
From: Aaron Lanterman <lanterma at ece.gatech.edu>
To: SDIY <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, April 24, 2008 1:03 PM
Subject: [sdiy] Odd OTA behavior


> I just got this e-mail from a student:
>
> >  I took the remaining 13700 and the 082 I was using and tried them
> > on another board and found that the 13700 wouldn't keep a steady
> > ~-13-14V at the Icon terminal - placing a resistor between +15 and
> > the terminal (trying with 520kOhm) would rise the voltage at Icon to
> > ~1.4V.
>
> I thought the voltage at a control pin of an OTA typically hung out a
> diode drop or two above the negative rail. What could he have done to
> make it measure at 1.4?
>
> (I'm thinking he probably hosed the chip somewhere along the line -
> blowing up a 13700 seems to be a rite of passage in my class; either
> that or he's flat out screwing up the measurement somehow.)
>
> - Aaron
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From louis at dompselaar.org  Thu Apr 24 22:02:25 2008
From: louis at dompselaar.org (Louis van Dompselaar)
Date: Thu, 24 Apr 2008 22:02:25 +0200
Subject: [sdiy] Looking for MC68705-P3
Message-ID: <4810E751.901@dompselaar.org>

Subject almost says it all.  I'm looking for four MC68705-P3 for some
old Midwest Analog boards.

Used ones are no problem, I have an EPROM eraser.

Louis



From xyzzy at sysabend.org  Fri Apr 25 09:05:15 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Fri, 25 Apr 2008 00:05:15 -0700
Subject: [sdiy] Microchip PSG - AY8930
In-Reply-To: <480EB74F.3040209@eventualdecline.com>
References: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>
	<480EB74F.3040209@eventualdecline.com>
Message-ID: <20080425070515.GZ59657@moo.sysabend.org>

On Tue, Apr 22, 2008 at 09:13:03PM -0700, Ben Lincoln wrote:
> http://www.datasheet4u.com/html/A/Y/8/AY8930_MicrochipTechnology.pdf.html
> 
> ...
> 
> If anyone is interested, but not $5 each interested, I got mine in 
> Jameco's small analogue/linear grab bag the first time and many more in 
> a large version of the same grab bag a month or two after that.

On a whim I stopped by Jameco and grabbed some of the grab bags.  Out of two
bags, I have at least 30 of these things now.  Probably more.

Gotta think of something to do with'em now...

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From ebrombaugh at earthlink.net  Fri Apr 25 16:23:20 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Fri, 25 Apr 2008 07:23:20 -0700
Subject: [sdiy] Microchip PSG - AY8930
In-Reply-To: <20080425070515.GZ59657@moo.sysabend.org>
References: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>	<480EB74F.3040209@eventualdecline.com>
	<20080425070515.GZ59657@moo.sysabend.org>
Message-ID: <4811E958.5000004@earthlink.net>

Tom Arnold wrote:
> On Tue, Apr 22, 2008 at 09:13:03PM -0700, Ben Lincoln wrote:
>> http://www.datasheet4u.com/html/A/Y/8/AY8930_MicrochipTechnology.pdf.html
>> ...
>>
>> If anyone is interested, but not $5 each interested, I got mine in 
>> Jameco's small analogue/linear grab bag the first time and many more in 
>> a large version of the same grab bag a month or two after that.
> 
> On a whim I stopped by Jameco and grabbed some of the grab bags.  Out of two
> bags, I have at least 30 of these things now.  Probably more.
> 
> Gotta think of something to do with'em now...


That brings back memories - back in high school ca. 1980 or so, I hooked 
an AY3-8910 up to my old 6502-based OSI Superboard and wrote a BASIC 
program to simulate seashore sounds. It had noise modulated by a slow 
LFO for waves, periodic foghorns and random seagull cries. I'm sure my 
recollection of it is better than it really sounded, but it was pretty 
cool to play with.

What to do with 30+ of these things? They're designed to hook up to an 
8-bit processor bus - how about a multi-voice MIDI-based synth, kinda 
like a SIDstation? You could probably drive a bunch of them with a cheap 
MCU (PIC, AVR, ARM, etc), but they're basically only PWM waves with 
fairly coarse amplitude modulation & built-in envelopes. Could be fun if 
you like that lo-tec '80s video game sound.

Eric




From somnium7 at gmail.com  Fri Apr 25 17:00:31 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Fri, 25 Apr 2008 11:00:31 -0400
Subject: [sdiy] Microchip PSG - AY8930
In-Reply-To: <4811E958.5000004@earthlink.net>
References: <5.1.0.14.2.20080423115247.0315c2d0@mail.all-electric.com>
	<480EB74F.3040209@eventualdecline.com>
	<20080425070515.GZ59657@moo.sysabend.org>
	<4811E958.5000004@earthlink.net>
Message-ID: <916920440804250800k2d06472of4dbd7ddc2b86b9@mail.gmail.com>

I believe you can program them to make white-noise sounds too. With a
bunch of simple resonant bandpass filters you could make an
interesting perc-synth type deal. Maybe even provide a Midi input for
it so you could play from a Midi controller with pads.

Mike

On Fri, Apr 25, 2008 at 10:23 AM, Eric Brombaugh
<ebrombaugh at earthlink.net> wrote:
> Tom Arnold wrote:
>
> > On Tue, Apr 22, 2008 at 09:13:03PM -0700, Ben Lincoln wrote:
> >
> > >
> http://www.datasheet4u.com/html/A/Y/8/AY8930_MicrochipTechnology.pdf.html
> > > ...
> > >
> > > If anyone is interested, but not $5 each interested, I got mine in
> Jameco's small analogue/linear grab bag the first time and many more in a
> large version of the same grab bag a month or two after that.
> > >
> >
> > On a whim I stopped by Jameco and grabbed some of the grab bags.  Out of
> two
> > bags, I have at least 30 of these things now.  Probably more.
> >
> > Gotta think of something to do with'em now...
> >
>
>
>  That brings back memories - back in high school ca. 1980 or so, I hooked an
> AY3-8910 up to my old 6502-based OSI Superboard and wrote a BASIC program to
> simulate seashore sounds. It had noise modulated by a slow LFO for waves,
> periodic foghorns and random seagull cries. I'm sure my recollection of it
> is better than it really sounded, but it was pretty cool to play with.
>
>  What to do with 30+ of these things? They're designed to hook up to an
> 8-bit processor bus - how about a multi-voice MIDI-based synth, kinda like a
> SIDstation? You could probably drive a bunch of them with a cheap MCU (PIC,
> AVR, ARM, etc), but they're basically only PWM waves with fairly coarse
> amplitude modulation & built-in envelopes. Could be fun if you like that
> lo-tec '80s video game sound.
>
>  Eric
>
>
>
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From tim102 at tstinchcombe.freeserve.co.uk  Fri Apr 25 20:11:15 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Fri, 25 Apr 2008 19:11:15 +0100
Subject: [sdiy] Odd OTA behavior
In-Reply-To: <81B95CAC-AF8E-4BBE-885D-0EE37D71C01A@ece.gatech.edu>
Message-ID: <000001c8a6ff$c5fa0fb0$67e5883e@stingo>

> >  I took the remaining 13700 and the 082 I was using and tried them
> > on another board and found that the 13700 wouldn't keep a steady  
> > ~-13-14V at the Icon terminal - placing a resistor between +15 and  
> > the terminal (trying with 520kOhm) would rise the voltage 
> at Icon to  
> > ~1.4V.
> 
> I thought the voltage at a control pin of an OTA typically 
> hung out a  
> diode drop or two above the negative rail. What could he have 
> done to  
> make it measure at 1.4?

1.4V sounds about right to me: both the equivalent schematic (page 3 of the
datasheet) show two diode drops (Q2 + D1) and the SPICE model has two diodes
too.

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk






From mirwin at marketbridge.ca  Fri Apr 25 20:34:43 2008
From: mirwin at marketbridge.ca (Mike I)
Date: Fri, 25 Apr 2008 14:34:43 -0400
Subject: [sdiy] Odd OTA behavior
References: <000001c8a6ff$c5fa0fb0$67e5883e@stingo>
Message-ID: <000701c8a703$08647180$badc47d1@ca>

If the OTA V(-) supply pin has mistakenly been connected to ground instead
of (-)15V, the Iabc pin will sit at two diode drops above ground (in the
case of LM13700) when current is fed through it from a resistor connected to
V(+).....

Have you checked to make sure the OTA is being powered from +/- 15V and not
+15V/GND ?



----- Original Message -----
From: Tim Stinchcombe <tim102 at tstinchcombe.freeserve.co.uk>
To: 'SDIY' <synth-diy at dropmix.xs4all.nl>
Sent: Friday, April 25, 2008 2:11 PM
Subject: RE: [sdiy] Odd OTA behavior


> > >  I took the remaining 13700 and the 082 I was using and tried them
> > > on another board and found that the 13700 wouldn't keep a steady
> > > ~-13-14V at the Icon terminal - placing a resistor between +15 and
> > > the terminal (trying with 520kOhm) would rise the voltage
> > at Icon to
> > > ~1.4V.
> >
> > I thought the voltage at a control pin of an OTA typically
> > hung out a
> > diode drop or two above the negative rail. What could he have
> > done to
> > make it measure at 1.4?
>
> 1.4V sounds about right to me: both the equivalent schematic (page 3 of
the
> datasheet) show two diode drops (Q2 + D1) and the SPICE model has two
diodes
> too.
>
> Tim
> __________________________________________________________
> Tim Stinchcombe
>
> Cheltenham, Glos, UK
> email: tim102 at tstinchcombe.freeserve.co.uk
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From lanterma at ece.gatech.edu  Fri Apr 25 21:01:14 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Fri, 25 Apr 2008 15:01:14 -0400
Subject: [sdiy] Odd OTA behavior
In-Reply-To: <000701c8a703$08647180$badc47d1@ca>
References: <000001c8a6ff$c5fa0fb0$67e5883e@stingo>
	<000701c8a703$08647180$badc47d1@ca>
Message-ID: <6CC57E0B-5132-4E09-8AD9-7DD9127A9058@ece.gatech.edu>


On Apr 25, 2008, at 2:34 PM, Mike I wrote:

> If the OTA V(-) supply pin has mistakenly been connected to ground  
> instead
> of (-)15V, the Iabc pin will sit at two diode drops above ground (in  
> the
> case of LM13700) when current is fed through it from a resistor  
> connected to
> V(+).....
>
> Have you checked to make sure the OTA is being powered from +/- 15V  
> and not
> +15V/GND ?

I'm now guessing that was it... he was running probably ran to the  
wrong rail on the broadboard. He rebuilt it and his OTA is working  
sensibly now.

- Aaron


From xyzzy at sysabend.org  Fri Apr 25 23:02:12 2008
From: xyzzy at sysabend.org (Tom Arnold)
Date: Fri, 25 Apr 2008 14:02:12 -0700
Subject: [sdiy] Motorola MC33110 Compander
Message-ID: <20080425210212.GD59657@moo.sysabend.org>

Has anyone played with the MC33110 compander vs the good'ol NE57x?  Its low
voltage, which should be fine for use with the low voltage BBDs that are
available.  The dynamic range looks to be comparable compression wise (
80db:40db vs 100db:50db ).

Of course its not made anymore, but there are a billion of so of these in
these grab bags and it got me thinking...

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------  



From mverbos at earthlink.net  Fri Apr 25 23:42:52 2008
From: mverbos at earthlink.net (mark verbos)
Date: Fri, 25 Apr 2008 17:42:52 -0400
Subject: [sdiy] CMOS clock problem
In-Reply-To: <20080422140831.M86373@wowway.com>
References: <EA8D79B6-58FE-4C74-9501-004B69BCCFD5@earthlink.net>
	<20080422140831.M86373@wowway.com>
Message-ID: <CE003E70-C47B-4A4D-9297-C7876CAEEBD8@earthlink.net>

um, duh.

I fixed it. Turns out I was taking the output from the wrong spot. I  
tapped it at the gate with a resistor on it's output rather than the  
one with the cap. I also had the 2 input pins on the gate with the  
cap after it tied together, instead of one to ground. Buchla did this  
and it seemed to work for him, but when I changed that to one input  
to ground it started working perfectly!

Thanks guys!


Mark







On Apr 22, 2008, at 10:11 AM, harrybissell at wowway.com wrote:

> Do you have a schematic ?
>
> I'm assuming its the traditional two-gate oscillator with
> one capacitor and two resistors.  One resistor and the cap
> sets the frequency, the other resistor is in series with the
> gate input to stop the input diodes from being too much of a pain
> in the @ss.  The resistor to the input should be about 10x the size
> of the frequency determining resistor.
>
> It could be that loading stops it from starting... is the output
> buffered ???
>
> H^) harry
>
>
>
> On Mon, 21 Apr 2008 16:44:43 -0400, mark verbos wrote
>> Hi,
>>
>> I have a high frequency clock made out of a couple 4001 gates in my
>> quantizer module. It doesn't like to start clocking when I turn it
>> on. Then I touch the pins with the scope probe and it starts going.
>> I  tried adding a 2.2M resistor to ground on the pin where the cap
>>  connects and I got it to start if I plug the connector in while the
>>  cabinet is powered up, but if I power cycle it while plugged in
>> it's  not oscillating. Is this something to do with the order that
>> the  power rails are coming up? It's only using +15 and GND, so I
>> don't  see how it could.
>>
>> Any ideas? I'm lost.
>>
>> Mark
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
> Harry Bissell & Nora Abdullah 4eva
>



From jhaible at debitel.net  Sat Apr 26 00:21:00 2008
From: jhaible at debitel.net (JH.)
Date: Sat, 26 Apr 2008 00:21:00 +0200
Subject: [sdiy] JFET switch question
Message-ID: <000301c8a722$a4a85100$0400a8c0@jhsilent>

Hi,

this is a question about using a JFET as an audio switch.

You all know the configuration:
D and S are used as the two switch contacts.
G is used to control the switch. A diode is connected to G (in opposite 
direction as the FET's own gate diode).
Speaking of a n-channel FET like the 2SK30, the anode of this diode goes to 
G. If you connect the cathode of this diode to the negative supply, the 
switch is open. A positive voltage, or even no external voltage at all, 
closes the switch, because the FET conducts.
So far so good.

Now, in most applications we see a high impedance resistor added from G to 
either D or S of the FET.
In some other applications, this resistor is missing, and we find a 
capacitor in the range of 10nF ... 100nF from G to GND.
The latter is obviously intended for smooth transitions rather than for hard 
switching.

Now I wonder: We rarely see this kind of switch without this capacitor and 
without the resistor.
Why is this? For a very simple switch, wouldn't just the FET and the diode 
be enough?
(Obviously no smooth transition without a capacitor - but what's the 
disadvantage compared to the FET + Resistor + Diode solution?)

JH. 



From ijfritz at comcast.net  Sat Apr 26 01:39:43 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Fri, 25 Apr 2008 17:39:43 -0600
Subject: [sdiy] JFET switch question
In-Reply-To: <000301c8a722$a4a85100$0400a8c0@jhsilent>
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
Message-ID: <6.2.1.2.2.20080425172332.020da2e8@mail.comcast.net>

At 04:21 PM 4/25/2008, JH. wrote:
>You all know the configuration:
>D and S are used as the two switch contacts.
>G is used to control the switch. A diode is connected to G (in opposite
>direction as the FET's own gate diode).
>Speaking of a n-channel FET like the 2SK30, the anode of this diode goes to
>G. If you connect the cathode of this diode to the negative supply, the
>switch is open. A positive voltage, or even no external voltage at all,
>closes the switch, because the FET conducts.
>So far so good.
>
>Now, in most applications we see a high impedance resistor added from G to
>either D or S of the FET.
>In some other applications, this resistor is missing, and we find a
>capacitor in the range of 10nF ... 100nF from G to GND.
>The latter is obviously intended for smooth transitions rather than for hard
>switching.
>
>Now I wonder: We rarely see this kind of switch without this capacitor and
>without the resistor.
>Why is this? For a very simple switch, wouldn't just the FET and the diode
>be enough?

If I understand what you are asking -- I believe the G potential is 
indeterminate if it is only connected to a reverse biased diode. Just 
floating at a very high impedance.  A large value resistor to the channel 
is basically a short circuit.  This ensures that the device is on the Vgs = 
0 curve of the Id vs Vds characteristics, where you have the lowest channel 
resistance and the best channel linearity.

   Ian




From ijfritz at comcast.net  Sat Apr 26 01:46:35 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Fri, 25 Apr 2008 17:46:35 -0600
Subject: [sdiy] JFET switch question
In-Reply-To: <000301c8a722$a4a85100$0400a8c0@jhsilent>
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
Message-ID: <6.2.1.2.2.20080425174005.020dbf98@mail.comcast.net>

At 04:21 PM 4/25/2008, JH. wrote:
>this is a question about using a JFET as an audio switch.
.....

>Speaking of a n-channel FET like the 2SK30

Oh, I forgot ....
Just a very minor point -- the 2SK30 is a depletion-mode MOSFET.
But I don't think this difference matters much as to how you think about 
it, except that the G-channel resistance is much larger.

   Ian 



From rtellason at verizon.net  Sat Apr 26 01:59:11 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Fri, 25 Apr 2008 19:59:11 -0400
Subject: [sdiy] JFET switch question
In-Reply-To: <6.2.1.2.2.20080425174005.020dbf98@mail.comcast.net>
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
	<6.2.1.2.2.20080425174005.020dbf98@mail.comcast.net>
Message-ID: <200804251959.12545.rtellason@verizon.net>

On Friday 25 April 2008 19:46, Ian Fritz wrote:
> At 04:21 PM 4/25/2008, JH. wrote:
> >this is a question about using a JFET as an audio switch.
>
> .....
>
> >Speaking of a n-channel FET like the 2SK30
>
> Oh, I forgot ....
> Just a very minor point -- the 2SK30 is a depletion-mode MOSFET.

No it's not,  according to the datasheet I have here:

http://classiccmp.org/rtellason/transistors-2sh-k.html

from Toshiba,  who makes the part.  I just double-checked,  as I thought I'd 
remembered it being a JFET...


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From ijfritz at comcast.net  Sat Apr 26 03:49:38 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Fri, 25 Apr 2008 19:49:38 -0600
Subject: [sdiy] JFET switch question
In-Reply-To: <200804251959.12545.rtellason@verizon.net>
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
	<6.2.1.2.2.20080425174005.020dbf98@mail.comcast.net>
	<200804251959.12545.rtellason@verizon.net>
Message-ID: <6.2.1.2.2.20080425194842.0210d650@mail.comcast.net>

At 05:59 PM 4/25/2008, Roy J. Tellason wrote:

>No it's not,  according to the datasheet I have here:
>
>http://classiccmp.org/rtellason/transistors-2sh-k.html
>
>from Toshiba,  who makes the part.  I just double-checked,  as I thought I'd
>remembered it being a JFET...


You're right.  I was going by this link, which is screwed up:
http://www.datasheet4u.com/share_search.php?sWord=2SK30 



From jhaible at debitel.net  Sat Apr 26 11:19:37 2008
From: jhaible at debitel.net (JH.)
Date: Sat, 26 Apr 2008 11:19:37 +0200
Subject: [sdiy] JFET switch question
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
	<6.2.1.2.2.20080425172332.020da2e8@mail.comcast.net>
Message-ID: <000e01c8a77e$a8f3ffa0$0400a8c0@jhsilent>

>If I understand what you are asking -- I believe the G potential is
>indeterminate if it is only connected to a reverse biased diode. Just
>floating at a very high impedance.  A large value resistor to the channel
>is basically a short circuit.  This ensures that the device is on the Vgs =
>0 curve of the Id vs Vds characteristics, where you have the lowest channel
>resistance and the best channel linearity.

Hi Ian,

yes, I think I understand that.
Theoretically, the G potential is indeterminate, except for leakage of the 
G-DS diode.
But that's also true for the circuit version with a 100nF cap from G to GND 
(without a resistor),
so DC-wise there should not be a difference if I just omit the 100nF.

I guess I'll add the resistors just to be sure. But it's a curcuit with 
about 30 such switches ...


JH. (working on the new combined Hammond Scanner Vibrato and generic 
Interpolating Scanner PCB.)







From denshiblocks at yahoo.com  Sat Apr 26 20:28:43 2008
From: denshiblocks at yahoo.com (denshi)
Date: Sat, 26 Apr 2008 11:28:43 -0700 (PDT)
Subject: [sdiy] Arp 4075 PCBs for sale
In-Reply-To: <6.2.1.2.2.20080425194842.0210d650@mail.comcast.net>
Message-ID: <9222.32082.qm@web56115.mail.re3.yahoo.com>

hi folks, i have a handful of Bananalogue LPFA module bare PCBs i'd like to pass on to the SDIY community (a.k.a. i need to raise some money for other projects). these are based faithfully on the Arp 4075 lowpass filter. info can be found at bananalogue.com or at the Analog Metropolis website. i'll email each buyer the build documents, but you'll need to source a tempco if you want accurate 1v/oct response. The module uses +/-15v (some component substitution might allow for operation on +/-12v but i make no promises on that) and accepts standard 4 pin power as on blacet/motm modules.

PCBs are $40 plus shipping each (double sided, professionally fabricated in the USA). Please send me a message with your address and i will write you back with my paypal info and a total including shipping. Thanks very much!


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From lanterma at ece.gatech.edu  Sun Apr 27 10:57:47 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 27 Apr 2008 04:57:47 -0400
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<8B3EF323-6D97-4C0F-8C98-A74FE89FD59F@ece.gatech.edu>
	<001201c8a5c4$c41172b0$1e2b3d80@gregory>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
Message-ID: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>

Howdy gang,

One of my students, Greg, is working on building the Bergfotron  
version of the Buchla 259 triangle core. He's using the Linear Systems  
LS358 (free samples they kindly sent) for the current mirror, and  
LM394s for the diff pair in the OTA and the expo converter (I had  
gotten a bunch of those from Futurlec a while back, IIRC).

The Bergfotron uses 5.1 k resistors. Our stockroom didn't have those  
so I told him to use 4.99Ks (I figure that's what's used in the  
original Buchla anyway).

After an afternoon of debugging, we got it oscillating with expo  
control. (I assist mostly by asking the students to talk me through  
the circuit, showing me things on the scope as the go, and they most  
often figure out the problem on their own while I pretend to be  
insightful... there's something about explaining your circuit (same  
thing works with computer programming) to someone else that makes it  
easier to find bigs.)

At higher frequencies, it looks pretty triangular, but at low  
frequencies it's more like a 20% triangle. (Also, when twisting  
various knobs to get the lowest frequency, it seems to only get down  
to 600 Hz, but I suspect that will be fixed once we get the triangle  
more triangular.)

The Bergfotron webpage emphasizes matching the resistors at the top of  
the OTA - it says "Buy a belt of 100 resistors and find two that give  
the exact same reading on a 4 1/2 digit ohmmeter. Any error here will  
give a non-symmetrical triangle wave." The resistors Greg is using  
currently measure at 4.963K and 4.972K, which are a far cry from  
measuring exactly the same to 4.5 digits. But, before I send Greg off  
to spend an afternoon at a DMM measuring a truckload of resistors, are  
there other sources of nontriangularness we should be looking at first?

Is that circuit really that sensitive to the resistor matching? That  
seems OK for a one-off like the Bergfotron, i.e. a design a person  
makes to build just one or two of - but it seems to me that would have  
severely limited the manufacturability of the original Buchla 259  
(although perhaps that shouldn't surprise me.)

- Aaron


From sdiy at haraldswerk.de  Sun Apr 27 12:06:27 2008
From: sdiy at haraldswerk.de (sdiy at haraldswerk.de)
Date: Sun, 27 Apr 2008 12:06:27 +0200
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
	<A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
Message-ID: <200804271206.27791.sdiy@haraldswerk.de>

Just replace one of teh resistors with a trimmer and look if you can trim it 
out. If not, there is an other fault.

Harald 


 Am Sonntag, 27. April 2008 10:57:47 schrieb Aaron Lanterman:
> Howdy gang,
>
> One of my students, Greg, is working on building the Bergfotron
> version of the Buchla 259 triangle core. He's using the Linear Systems
> LS358 (free samples they kindly sent) for the current mirror, and
> LM394s for the diff pair in the OTA and the expo converter (I had
> gotten a bunch of those from Futurlec a while back, IIRC).
>
> The Bergfotron uses 5.1 k resistors. Our stockroom didn't have those
> so I told him to use 4.99Ks (I figure that's what's used in the
> original Buchla anyway).
>
> After an afternoon of debugging, we got it oscillating with expo
> control. (I assist mostly by asking the students to talk me through
> the circuit, showing me things on the scope as the go, and they most
> often figure out the problem on their own while I pretend to be
> insightful... there's something about explaining your circuit (same
> thing works with computer programming) to someone else that makes it
> easier to find bigs.)
>
> At higher frequencies, it looks pretty triangular, but at low
> frequencies it's more like a 20% triangle. (Also, when twisting
> various knobs to get the lowest frequency, it seems to only get down
> to 600 Hz, but I suspect that will be fixed once we get the triangle
> more triangular.)
>
> The Bergfotron webpage emphasizes matching the resistors at the top of
> the OTA - it says "Buy a belt of 100 resistors and find two that give
> the exact same reading on a 4 1/2 digit ohmmeter. Any error here will
> give a non-symmetrical triangle wave." The resistors Greg is using
> currently measure at 4.963K and 4.972K, which are a far cry from
> measuring exactly the same to 4.5 digits. But, before I send Greg off
> to spend an afternoon at a DMM measuring a truckload of resistors, are
> there other sources of nontriangularness we should be looking at first?
>
> Is that circuit really that sensitive to the resistor matching? That
> seems OK for a one-off like the Bergfotron, i.e. a design a person
> makes to build just one or two of - but it seems to me that would have
> severely limited the manufacturability of the original Buchla 259
> (although perhaps that shouldn't surprise me.)
>
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy




From sdiy at haraldswerk.de  Sun Apr 27 12:17:42 2008
From: sdiy at haraldswerk.de (sdiy at haraldswerk.de)
Date: Sun, 27 Apr 2008 12:17:42 +0200
Subject: [sdiy] Wanted 2sc1583
Message-ID: <200804271217.42186.sdiy@haraldswerk.de>

Hi list,

I  am looking for at least one 2sc1583. I have a PCB for a moog lp clone witch 
is layed out for an 2sc1583. Is anybody out there to sell or trade me one? 
Some more are welcom.
I am willing to trade 3080 or 3280 for it. Please eMail offlist. I am located 
in Germany.

Tahbks 

Harald


From Stromeko at nexgo.de  Sun Apr 27 12:55:34 2008
From: Stromeko at nexgo.de (ASSI)
Date: Sun, 27 Apr 2008 12:55:34 +0200
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
	<A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
Message-ID: <200804271255.34627.Stromeko@nexgo.de>

On Sonntag 27 April 2008, Aaron Lanterman wrote:
> The Bergfotron webpage emphasizes matching the resistors at the top
> of the OTA - it says "Buy a belt of 100 resistors and find two that
> give the exact same reading on a 4 1/2 digit ohmmeter. Any error here
> will give a non-symmetrical triangle wave." The resistors Greg is
> using currently measure at 4.963K and 4.972K, which are a far cry
> from measuring exactly the same to 4.5 digits. But, before I send
> Greg off to spend an afternoon at a DMM measuring a truckload of
> resistors, are there other sources of nontriangularness we should be
> looking at first?

Simply switch the two resistors and see if you now get an 80% triangle.  
Or combine a 4.7k resistor with a 330 trimmer and try to get symmetry 
by adjusting that.  If not, maybe the matching of the transistors isn't 
all that great.

> Is that circuit really that sensitive to the resistor matching? That
> seems OK for a one-off like the Bergfotron, i.e. a design a person
> makes to build just one or two of - but it seems to me that would
> have severely limited the manufacturability of the original Buchla
> 259 (although perhaps that shouldn't surprise me.)

E96 values are easily obtained in 0.1% tolerance.  While still a factor 
of 5 short of the required matching, these should match fairly well in 
just a few tries on a bridge setup.  Matching pairs of 1% resistors 
takes a while longer I guess, but not overly so.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Factory and User Sound Singles for Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds



From hondareyte.luc at laposte.net  Sun Apr 27 13:21:35 2008
From: hondareyte.luc at laposte.net (Luc Hondareyte)
Date: Sun, 27 Apr 2008 13:21:35 +0200
Subject: [sdiy] Wanted 2sc1583
In-Reply-To: <200804271217.42186.sdiy@haraldswerk.de>
References: <200804271217.42186.sdiy@haraldswerk.de>
Message-ID: <1209295295.5593.2.camel@casper.acme>

Le dimanche 27 avril 2008 ? 12:17 +0200, sdiy at haraldswerk.de a ?crit :
> Hi list,
> 
> I  am looking for at least one 2sc1583. I have a PCB for a moog lp clone witch 
> is layed out for an 2sc1583. Is anybody out there to sell or trade me one? 
> Some more are welcom.
> I am willing to trade 3080 or 3280 for it. Please eMail offlist. I am located 
> in Germany.
> 
> Tahbks 
> 
> Harald

Hello,

It's available from "Electronique Diffusion" for 3? each.
http://www.electronique-diffusion.fr/product_info.php?products_id=32073

Regards,

Luc



From pfperry at melbpc.org.au  Sun Apr 27 13:58:41 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Sun, 27 Apr 2008 21:58:41 +1000
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <200804271255.34627.Stromeko@nexgo.de>
Message-ID: <004701c8a85e$0a2e2e50$8501a8c0@ice9>

Suppose you have resistors that are accurate to within P%.
Suppose you have N of them.

Then, there must be at least one pair among them, that are within 2P/(N-1)
of each other. Approximately. I think.
(hint: think of the 'worst' distribution of values)

Hoping that cheers somebody up.

paul perry Melbourne Australia




From ijfritz at comcast.net  Sun Apr 27 17:15:49 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Sun, 27 Apr 2008 09:15:49 -0600
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<8B3EF323-6D97-4C0F-8C98-A74FE89FD59F@ece.gatech.edu>
	<001201c8a5c4$c41172b0$1e2b3d80@gregory>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
	<A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
Message-ID: <6.2.1.2.2.20080427091430.020dd7b8@mail.comcast.net>

At 02:57 AM 4/27/2008, Aaron Lanterman wrote:
>The resistors Greg is using
>currently measure at 4.963K and 4.972K, which are a far cry from
>measuring exactly the same to 4.5 digits. ....

Add 10R to the small one?



From don at till.com  Sun Apr 27 17:28:15 2008
From: don at till.com (Donald Tillman)
Date: Sun, 27 Apr 2008 08:28:15 -0700
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu> (message
	from Aaron Lanterman on Sun, 27 Apr 2008 04:57:47 -0400)
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<8B3EF323-6D97-4C0F-8C98-A74FE89FD59F@ece.gatech.edu>
	<001201c8a5c4$c41172b0$1e2b3d80@gregory>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
	<A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
Message-ID: <m2y76ztj00.fsf@till.com>

   > From: Aaron Lanterman <lanterma at ece.gatech.edu>
   > Date: Sun, 27 Apr 2008 04:57:47 -0400
   > 
   > One of my students, Greg, is working on building the Bergfotron
   > version of the Buchla 259 triangle core.

Hey Aaron,

He'll need a large stock of colorful inks to do that!   :-)

   > At higher frequencies, it looks pretty triangular, but at low
   > frequencies it's more like a 20% triangle. (Also, when twisting
   > various knobs to get the lowest frequency, it seems to only get
   > down to 600 Hz, but I suspect that will be fixed once we get the
   > triangle more triangular.)

Hey, at high frequencies *everything* looks triangluar.  :-)

A slight resistor mismatch wouldn't cause that; I strongly suspect a
wiring error.

  -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com


From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 27 17:43:58 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 27 Apr 2008 16:43:58 +0100
Subject: [sdiy] JFET switch question
In-Reply-To: <000301c8a722$a4a85100$0400a8c0@jhsilent>
Message-ID: <000001c8a87d$85dd4b70$628b4754@stingo>

> Now I wonder: We rarely see this kind of switch without this 
> capacitor and 
> without the resistor.
> Why is this? For a very simple switch, wouldn't just the FET 
> and the diode 
> be enough?
> (Obviously no smooth transition without a capacitor - but what's the 
> disadvantage compared to the FET + Resistor + Diode solution?)

I have a couple of old JFET books, which have a little about this circuit in
them. In the first, without a G-D or G-S resistor, the development seems to
be along these lines:

- if you apply the switch control voltage directly to the gate, then due to
internal G-D and G-S capacitances, the switching voltage couples to the
switch output, so you get transients in the output when the control voltage
changes.

- the diode helps with this, as it better isolates the control voltage from
the gate

- however, with the diode reverse-biased for the switch to be ON, there is
now no path for a current to remove the charge in the reverse-biased channel
junction, which is needed to allow the JFET to actually turn on. The cap is
necessary to supply this path, the implication being that the JFET might not
actually switch on without it.

The second book does have a G-S resistor, which it says does supply this
path for the channel junction to discharge, but says that adding a capacitor
to shunt the diode will greatly reduce the turn-on time.

Thus it looks like if you have the resistor you could ignore the cap (and
suffer slower switching times), but without the resistor, you really do need
the cap!

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk








From jhaible at debitel.net  Sun Apr 27 17:48:18 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 27 Apr 2008 17:48:18 +0200
Subject: [sdiy] JFET switch question
References: <000001c8a87d$85dd4b70$628b4754@stingo>
Message-ID: <001101c8a87e$1d8ee9b0$0400a8c0@jhsilent>

Interesting!

Thanks for looking this up.

JH.

----- Original Message ----- 
From: "Tim Stinchcombe" <tim102 at tstinchcombe.freeserve.co.uk>
To: "'JH.'" <jhaible at debitel.net>; <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, April 27, 2008 5:43 PM
Subject: RE: [sdiy] JFET switch question


> Now I wonder: We rarely see this kind of switch without this
> capacitor and
> without the resistor.
> Why is this? For a very simple switch, wouldn't just the FET
> and the diode
> be enough?
> (Obviously no smooth transition without a capacitor - but what's the
> disadvantage compared to the FET + Resistor + Diode solution?)

I have a couple of old JFET books, which have a little about this circuit in
them. In the first, without a G-D or G-S resistor, the development seems to
be along these lines:

- if you apply the switch control voltage directly to the gate, then due to
internal G-D and G-S capacitances, the switching voltage couples to the
switch output, so you get transients in the output when the control voltage
changes.

- the diode helps with this, as it better isolates the control voltage from
the gate

- however, with the diode reverse-biased for the switch to be ON, there is
now no path for a current to remove the charge in the reverse-biased channel
junction, which is needed to allow the JFET to actually turn on. The cap is
necessary to supply this path, the implication being that the JFET might not
actually switch on without it.

The second book does have a G-S resistor, which it says does supply this
path for the channel junction to discharge, but says that adding a capacitor
to shunt the diode will greatly reduce the turn-on time.

Thus it looks like if you have the resistor you could ignore the cap (and
suffer slower switching times), but without the resistor, you really do need
the cap!

Tim
__________________________________________________________
Tim Stinchcombe

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk









From ijfritz at comcast.net  Sun Apr 27 17:59:44 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Sun, 27 Apr 2008 09:59:44 -0600
Subject: [sdiy] JFET switch question
In-Reply-To: <000001c8a87d$85dd4b70$628b4754@stingo>
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
	<000001c8a87d$85dd4b70$628b4754@stingo>
Message-ID: <6.2.1.2.2.20080427095525.021f2610@mail.comcast.net>

At 09:43 AM 4/27/2008, Tim Stinchcombe wrote:
>- however, with the diode reverse-biased for the switch to be ON, there is
>now no path for a current to remove the charge in the reverse-biased channel
>junction, which is needed to allow the JFET to actually turn on. The cap is
>necessary to supply this path, the implication being that the JFET might not
>actually switch on without it.

That's exactly what I was trying to explain before. Guess I didn't say it 
very well.  You can't just leave the gate open-circuit because its 
potential is indeterminate.  It needs to be tied to something that will 
bias the device into conduction.

   Ian 



From jhaible at debitel.net  Sun Apr 27 20:38:30 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 27 Apr 2008 20:38:30 +0200
Subject: [sdiy] JFET switch question
References: <000301c8a722$a4a85100$0400a8c0@jhsilent>
	<000001c8a87d$85dd4b70$628b4754@stingo>
	<6.2.1.2.2.20080427095525.021f2610@mail.comcast.net>
Message-ID: <000501c8a895$e426ca40$0400a8c0@jhsilent>


>----- Original Message ----- 
>From: "Ian Fritz" <ijfritz at comcast.net>
>To: <tim102 at tstinchcombe.freeserve.co.uk>; "'JH.'" <jhaible at debitel.net>; 
><synth-diy at dropmix.xs4all.nl>
>Sent: Sunday, April 27, 2008 5:59 PM
>Subject: RE: [sdiy] JFET switch question
>

>At 09:43 AM 4/27/2008, Tim Stinchcombe wrote:
>>- however, with the diode reverse-biased for the switch to be ON, there is
>>now no path for a current to remove the charge in the reverse-biased 
>>channel
>>junction, which is needed to allow the JFET to actually turn on. The cap 
>>is
>>necessary to supply this path, the implication being that the JFET might 
>>not
>>actually switch on without it.
>
>That's exactly what I was trying to explain before. Guess I didn't say it
>very well.  You can't just leave the gate open-circuit because its
>potential is indeterminate.  It needs to be tied to something that will
>bias the device into conduction.

.. and I'm not sure I've completely understood it yet, even though I'm 
thankful to both of you for trying to explain.
The case with the resistor is clear.
The case with the capacitor ... well ...hmm.
Wouldn't an external capacitor which is tied to GND _preserve_ charge 
instead of removing it?

JH.







From lanterma at ece.gatech.edu  Sun Apr 27 21:11:24 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 27 Apr 2008 15:11:24 -0400
Subject: [sdiy] Wanted 2sc1583
In-Reply-To: <200804271217.42186.sdiy@haraldswerk.de>
References: <200804271217.42186.sdiy@haraldswerk.de>
Message-ID: <ED60683B-9FF5-4D00-BE71-D80C08617B24@ece.gatech.edu>


On Apr 27, 2008, at 6:17 AM, sdiy at haraldswerk.de wrote:

> I  am looking for at least one 2sc1583. I have a PCB for a moog lp  
> clone witch
> is layed out for an 2sc1583. Is anybody out there to sell or trade  
> me one?
> Some more are welcom.

I bought a bunch from Limor, who stockpiled a bunch of those Japanese  
transistors for her x0xb0x project.

http://www.adafruit.com/index.php?main_page=index&cPath=7

I don't see them listed but you could ask her.

- Aaron


From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 27 21:12:24 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 27 Apr 2008 20:12:24 +0100
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
Message-ID: <000001c8a89a$a2773350$628b4754@stingo>

> At higher frequencies, it looks pretty triangular, but at low  
> frequencies it's more like a 20% triangle. (Also, when twisting  
> various knobs to get the lowest frequency, it seems to only get down  
> to 600 Hz, but I suspect that will be fixed once we get the triangle  
> more triangular.)

Since the lack of symmetry would tend to indicate some imbalance in the
current into/out of the main timing cap, are you using high input impedance
op amps like the TL072s shown on the Bergfotron schematics? If a
bipolar-input type, could the input bias current be causing grief? A quick
calculation suggests this idea might be a bit iffy, but it was just a
thought...

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk





From tim102 at tstinchcombe.freeserve.co.uk  Sun Apr 27 21:42:33 2008
From: tim102 at tstinchcombe.freeserve.co.uk (Tim Stinchcombe)
Date: Sun, 27 Apr 2008 20:42:33 +0100
Subject: [sdiy] JFET switch question
In-Reply-To: <000501c8a895$e426ca40$0400a8c0@jhsilent>
Message-ID: <000001c8a89e$dad1a290$628b4754@stingo>

> >At 09:43 AM 4/27/2008, Tim Stinchcombe wrote:
> >>- however, with the diode reverse-biased for the switch to 
> be ON, there is
> >>now no path for a current to remove the charge in the 
> reverse-biased 
> >>channel
> >>junction, which is needed to allow the JFET to actually 
> turn on. The cap 
> >>is
> >>necessary to supply this path, the implication being that 
> the JFET might 
> >>not
> >>actually switch on without it.
> >
> >That's exactly what I was trying to explain before. Guess I 
> didn't say it
> >very well.  You can't just leave the gate open-circuit because its
> >potential is indeterminate.  It needs to be tied to 
> something that will
> >bias the device into conduction.
> 
> .. and I'm not sure I've completely understood it yet, even 
> though I'm 
> thankful to both of you for trying to explain.
> The case with the resistor is clear.
> The case with the capacitor ... well ...hmm.
> Wouldn't an external capacitor which is tied to GND _preserve_ charge 
> instead of removing it?

Well since I made that post I have been trying to get *my* head round it
too, and have even tried a few simulations, but I'm sure I'm not there yet
either!

However, to be clear, in the circuits in these books I'm looking at the cap
shunts the diode (i.e. is in parallel to it), and is *not* connected to
ground: JFET gate to anode + one end of cap; switching voltage to cathode +
other end of cap. Thus when the voltage switches, it is possible for a
'spike' to get through the cap. (I think I just about see the switching 'on'
case, but not 'off' yet...)

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk







From mverbos at earthlink.net  Sun Apr 27 21:46:27 2008
From: mverbos at earthlink.net (mark verbos)
Date: Sun, 27 Apr 2008 15:46:27 -0400
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <m2y76ztj00.fsf@till.com>
References: <1984801202.1084091208824103583.JavaMail.root@mail5.gatech.edu>
	<8B3EF323-6D97-4C0F-8C98-A74FE89FD59F@ece.gatech.edu>
	<001201c8a5c4$c41172b0$1e2b3d80@gregory>
	<2AD99D1B-FD2E-475D-9DE5-D0B536F10CCC@ece.gatech.edu>
	<A5A713F2-688A-4642-A252-04E957AE2379@ece.gatech.edu>
	<m2y76ztj00.fsf@till.com>
Message-ID: <53E9BC83-543C-49CF-9AD5-1BE37CC1B42F@earthlink.net>

I'm with Don on this one. Even with unmatched transistors and 1%  
resistors, the symmetry in all the ones I have build is pretty close.  
In the Buchlas, he didn't use that tightly matched resistors. The  
259's trimmer goes through a 10M resistor to ground and the 208  
doesn't even have a trimmer. I'd recheck the build. Be sure there's a  
FET input OP Amp in the integrator.

Mark





On Apr 27, 2008, at 11:28 AM, Donald Tillman wrote:

>> From: Aaron Lanterman <lanterma at ece.gatech.edu>
>> Date: Sun, 27 Apr 2008 04:57:47 -0400
>>
>> One of my students, Greg, is working on building the Bergfotron
>> version of the Buchla 259 triangle core.
>
> Hey Aaron,
>
> He'll need a large stock of colorful inks to do that!   :-)
>
>> At higher frequencies, it looks pretty triangular, but at low
>> frequencies it's more like a 20% triangle. (Also, when twisting
>> various knobs to get the lowest frequency, it seems to only get
>> down to 600 Hz, but I suspect that will be fixed once we get the
>> triangle more triangular.)
>
> Hey, at high frequencies *everything* looks triangluar.  :-)
>
> A slight resistor mismatch wouldn't cause that; I strongly suspect a
> wiring error.
>
>   -- Don
>
> -- 
> Don Tillman
> Palo Alto, California
> don at till.com
> http://www.till.com
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From mverbos at earthlink.net  Sun Apr 27 21:51:45 2008
From: mverbos at earthlink.net (mark verbos)
Date: Sun, 27 Apr 2008 15:51:45 -0400
Subject: [sdiy] LED drive circuits
Message-ID: <C0E20CE3-5D3B-4B56-8D9C-CCD1FAE441B1@earthlink.net>

Speaking of Buchla...

I opened up a Buchla 255 module to do a mod to it and I was very  
surprised to see the LED drive circuit he's using. It's just from the  
output opamp (LF353 in this case) through a 10k resistor to the LED  
anode and a 62k resistor to +15. The cathode of the LED to ground. I  
have been under the impression that you needed to have more to drive  
an LED than that. Is this an accepted solution or cheaping out? Also,  
if you put a bipolar LED in there would you be able to get green when  
the signal is positive and red when it's negative? Just curious really.



Mark


From jhaible at debitel.net  Sun Apr 27 22:16:33 2008
From: jhaible at debitel.net (JH.)
Date: Sun, 27 Apr 2008 22:16:33 +0200
Subject: [sdiy] JFET switch question
References: <000001c8a89e$dad1a290$628b4754@stingo>
Message-ID: <000501c8a8a3$96a7e3e0$0400a8c0@jhsilent>

>However, to be clear, in the circuits in these books I'm looking at the cap
>shunts the diode (i.e. is in parallel to it), and is *not* connected to
>ground: JFET gate to anode + one end of cap; switching voltage to cathode +
>other end of cap. Thus when the voltage switches, it is possible for a
>'spike' to get through the cap. (I think I just about see the switching 
>'on'
>case, but not 'off' yet...)

Well then, _that_ is the classic way to speed up switching by providing a 
low impedance path dynamically, for charging and discharging an internal or 
parasitic capacitance. (Practically the opposite of what I had in mind.)

JH. 



From lanterma at ece.gatech.edu  Sun Apr 27 23:24:27 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Sun, 27 Apr 2008 17:24:27 -0400
Subject: [sdiy] What to do with unused OTAs and buffers on an LM13700
Message-ID: <B244BEAB-42C2-4EB9-A42A-D97BEC000CE4@ece.gatech.edu>

For unused op amps with a split supply, I know to ground the +  
terminal and run the - terminal to the output.

Is there a "best practice" for what to do with unused buffers and OTAs  
on the LM13700?

- Aaron


From denshiblocks at yahoo.com  Mon Apr 28 02:30:18 2008
From: denshiblocks at yahoo.com (denshi)
Date: Sun, 27 Apr 2008 17:30:18 -0700 (PDT)
Subject: [sdiy] Re: Arp 4075 PCBs for sale
Message-ID: <418820.18200.qm@web56107.mail.re3.yahoo.com>

any more takers?  i have a few more boards left, thanks!

seth
bananalogue.com


> From: denshi <denshiblocks at yahoo.com>
> Subject: Arp 4075 PCBs for sale
> To: synth-diy at dropmix.xs4all.nl
> Date: Saturday, April 26, 2008, 11:28 AM
> hi folks, i have a handful of Bananalogue LPFA module bare
> PCBs i'd like to pass on to the SDIY community (a.k.a.
> i need to raise some money for other projects). these are
> based faithfully on the Arp 4075 lowpass filter. info can
> be found at bananalogue.com or at the Analog Metropolis
> website. i'll email each buyer the build documents, but
> you'll need to source a tempco if you want accurate
> 1v/oct response. The module uses +/-15v (some component
> substitution might allow for operation on +/-12v but i make
> no promises on that) and accepts standard 4 pin power as on
> blacet/motm modules.
> 
> PCBs are $40 plus shipping each (double sided,
> professionally fabricated in the USA). Please send me a
> message with your address and i will write you back with my
> paypal info and a total including shipping. Thanks very
> much!
>


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From pfperry at melbpc.org.au  Mon Apr 28 02:45:49 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 28 Apr 2008 10:45:49 +1000
Subject: [sdiy] What to do with unused OTAs and buffers on an LM13700
In-Reply-To: <B244BEAB-42C2-4EB9-A42A-D97BEC000CE4@ece.gatech.edu>
Message-ID: <005101c8a8c9$34c863e0$8501a8c0@ice9>

If one side of the 13700 is unused, I'd suggest tying the inputs to ground.
And tie the unused buffer input to ground, if you like.
No need to do anything with the outputs.

paul perry Melbourne Australia

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Aaron Lanterman
Sent: Monday, 28 April 2008 7:24 AM
To: SDIY
Subject: [sdiy] What to do with unused OTAs and buffers on an LM13700

For unused op amps with a split supply, I know to ground the +  
terminal and run the - terminal to the output.

Is there a "best practice" for what to do with unused buffers and OTAs  
on the LM13700?

/listinfo/synth-diy



From pfperry at melbpc.org.au  Mon Apr 28 02:59:41 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 28 Apr 2008 10:59:41 +1000
Subject: [sdiy] Resistor matching in Bergfotron complex VCO
In-Reply-To: <000001c8a89a$a2773350$628b4754@stingo>
Message-ID: <005301c8a8cb$2509b600$8501a8c0@ice9>

I expect Tim is right on this.
Whenever I have seen a triangle generator that was asymmetric only at low
frequencies, it was due to the charge/discharge currents (tiny at low
frequencies) being themselves asymmetric, due to input leakage current in
the op amp.

paul perry Melbourne Australia

-----Original Message-----
Since the lack of symmetry would tend to indicate some imbalance in the
current into/out of the main timing cap, are you using high input impedance
op amps like the TL072s shown on the Bergfotron schematics? If a
bipolar-input type, could the input bias current be causing grief? A quick
calculation suggests this idea might be a bit iffy, but it was just a
thought...
Tim Stinchcombe 
.xs4all.nl/mailman/listinfo/synth-diy



From aankrom at bluemarble.net  Mon Apr 28 04:28:26 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 22:28:26 -0400
Subject: [sdiy] Re: Arp 4075 PCBs for sale
References: <418820.18200.qm@web56107.mail.re3.yahoo.com>
Message-ID: <009201c8a8d7$8bd05360$0202a8c0@positronium>

How about Arp 4072 PCB's - that use NTE43's?
Wait, I think I saw a pattern somewhere, but maybe that was the 4075 and it 
didn't have the bias circuit. What, they couldn't find enough 22MOhm 
resistors?

I have to ask why 4075 vs. 4072?


AA

----- Original Message ----- 
From: "denshi" <denshiblocks at yahoo.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, April 27, 2008 8:30 PM
Subject: [sdiy] Re: Arp 4075 PCBs for sale


> any more takers?  i have a few more boards left, thanks!
>
> seth
> bananalogue.com
>
>
>> From: denshi <denshiblocks at yahoo.com>
>> Subject: Arp 4075 PCBs for sale
>> To: synth-diy at dropmix.xs4all.nl
>> Date: Saturday, April 26, 2008, 11:28 AM
>> hi folks, i have a handful of Bananalogue LPFA module bare
>> PCBs i'd like to pass on to the SDIY community (a.k.a.
>> i need to raise some money for other projects). these are
>> based faithfully on the Arp 4075 lowpass filter. info can
>> be found at bananalogue.com or at the Analog Metropolis
>> website. i'll email each buyer the build documents, but
>> you'll need to source a tempco if you want accurate
>> 1v/oct response. The module uses +/-15v (some component
>> substitution might allow for operation on +/-12v but i make
>> no promises on that) and accepts standard 4 pin power as on
>> blacet/motm modules.
>>
>> PCBs are $40 plus shipping each (double sided,
>> professionally fabricated in the USA). Please send me a
>> message with your address and i will write you back with my
>> paypal info and a total including shipping. Thanks very
>> much!
>>
>
>
> 
> ____________________________________________________________________________________
> Be a better friend, newshound, and
> know-it-all with Yahoo! Mobile.  Try it now. 
> http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From aankrom at bluemarble.net  Mon Apr 28 04:34:41 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 22:34:41 -0400
Subject: [sdiy] Wanted 2sc1583
References: <200804271217.42186.sdiy@haraldswerk.de>
Message-ID: <00ae01c8a8d8$6b6591c0$0202a8c0@positronium>

You can use an NTE42. It's probably a relabeled 2SC1583 anyway. The ones I 
have are. Not so easy to tell when you happen to get one of the old ECG42 
numbers because I think they "house labeled" those or something.

Almost all of the NTE replacement parts are relabeled. Which is why you 
can't get CA3080's or CA3080T's in the NTE numbers anymore - because their 
lifetime supply ran out. But you can look right under the NTE number and see 
CA3080E plain as day.

My NTE43's (2SA798) are a little more obvious than my NTE42's.

AA

> Hi list,
>
> I  am looking for at least one 2sc1583. I have a PCB for a moog lp clone 
> witch
> is layed out for an 2sc1583. Is anybody out there to sell or trade me one?
> Some more are welcom.
> I am willing to trade 3080 or 3280 for it. Please eMail offlist. I am 
> located
> in Germany.
>
> Tahbks
>
> Harald
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From aankrom at bluemarble.net  Mon Apr 28 04:40:00 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 22:40:00 -0400
Subject: [sdiy] I want 2SA1349's & 2SC3381's - screw 2sc1583's!
References: <200804271217.42186.sdiy@haraldswerk.de>
Message-ID: <00b501c8a8d9$296c6b80$0202a8c0@positronium>

Mostly the 2SA1349's. Unless you're the Bozo selling them for $20 on eBay. 
Funny how when you have 2 of something you find a need for 6 or 20.

I think I would trade my 2 2SC3381's for 2 2SA1349's even. Even Steven?

cheers,
Anthony 




From aankrom at bluemarble.net  Mon Apr 28 04:48:28 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 22:48:28 -0400
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the
	urgetomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9><01d101c8a3db$78eca880$0202a8c0@positronium><008201c8a4e2$87151890$b000a8c0@curley>
	<20080423142712.M26886@wowway.com>
Message-ID: <00c201c8a8da$584a2450$0202a8c0@positronium>


> Its funny to me how products that I thought, well... er...
> well it HAS got a BBD in it (if you catch my drift)...

Yes we know Harry...

> were not too viable, have become loved and wanted. Its not just the
> RatShack electronic reverb (which I did buy and build)... but also
> EH Electric Mistress (which I did NOT buy as I thought it sucked..)

I looked at the schematic and thought it sucked. I think I can duplicate a 
Flanger Hoax without a schematic and get better results too.

> I guess there is no accounting for taste. If you love 'lo-fi' the
> Radio Shack reverb has it in spades...

Too right! But the 'lo-fi' is very tweakable from 'lo'er to 'hi'er, but 
never quite 'hi-fi' and many lateral turns as well (like modding it to have 
a true wet/dry fader...).
But the sliders and the 'li'l black box' look are what make it a gem. 
(Putting a BL3208A in is still pretty damn cool too!)

> H^) harry

Frasier,
Anthony 




From aankrom at bluemarble.net  Mon Apr 28 04:49:56 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 22:49:56 -0400
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
	tomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
	<008201c8a4e2$87151890$b000a8c0@curley>
Message-ID: <00cb01c8a8da$8c6cda20$0202a8c0@positronium>

You're kidding? I don't care what anyone says, it's a good design. For what 
it really does and more.

----- Original Message ----- 
From: "Paul Schreiber" <pschreiber at sbcglobal.net>
To: "anthony" <aankrom at bluemarble.net>; <Synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, April 22, 2008 9:37 PM
Subject: Re: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge 
tomodify...


> Jeez, I designed this thing in 1980 and it won't die :)
>
> Paul S.
>
> ----- Original Message ----- 
> From: "anthony" <aankrom at bluemarble.net>
> To: <Synth-diy at dropmix.xs4all.nl>
> Sent: Monday, April 21, 2008 1:13 PM
> Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge 
> tomodify...
>
>
>> Hi guys,
>>
>> So I have one Realistic Electronic Reverb: the greatest effect to use for 
>> not quite what it was intended for. This booger is a great noisemaker and 
>> lots of fun with it's slider controls. It's even better with a few tweaks 
>> to the circuit: more gain and high-end roll-off to the regen path, 471pF 
>> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in place 
>> of the AN6550's, socket for the timing cap to play with different values, 
>> adding 0.1 uF bypass caps here and there, and the latest greatest mod: 
>> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've 
>> thought about wiring 2 or 3 in series, the BL3208A being something like 
>> $3.75 in price. Next planned mod is making the "DEPTH" control into a 
>> true wet/dry crossfader, which is a non-trivial task, but not impossible: 
>> I think a 1 uf cap and a couple 100kOhm resistors to put the bias in the 
>> right place again and cutting the traces on the PCB and rewiring 
>> accordingly.
>>
>> SO I've been trying to buy another one on eBay for what I got my first 
>> one for ($12.00) and it's been a daunting task. People are catching on to 
>> how cool these are.
>>
>> I'm not one to care much for collectability in gear because I like to be 
>> able to use my gear to the fullest. But I'm planning some more mods that 
>> will actuall involve cutting into the unit and I'm beginning to wonder 
>> whether I should. I wanted to add a DP3T selector switch to select 
>> between various timing caps (if I can just find a good place on the front 
>> for a toggle switch to go...), and adding some brass body contacts to 
>> bring it (sort of) into the realm of circuit bending. I must admit that I 
>> don't actually hold to the philosphy of circuit bending although I enjoy 
>> hearing some of the results. I don't think wiring various contacts and 
>> capacitors to the timing cap connections could be considered circuit 
>> bending in its true spirit because they are not random bends, but 
>> carefully thought out connections. Putting your fingers across the timing 
>> cap terminals is very fun: it depends on the pressure exerted so it has a 
>> playability factor to it: you can quickly (or slowly) descend into the 
>> realm of 2 second delays and back again. With the increased number of 
>> stages in the BL3208A, it's even better: repeats just go on and on 
>> without sounding like an oscillation, but it'll oscillate too - and how!
>>
>> So I'm wondering: should I do it? I mean even when they're going at $40 
>> on eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or 
>> something.
>>
>> Also, if anyone has DONE the wet/dry crossfade mod and would like to 
>> share, I'd appreciate that a lot. Thanx...
>>
>>
>> Cheers,
>> Anthony
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
> 




From aankrom at bluemarble.net  Mon Apr 28 05:13:54 2008
From: aankrom at bluemarble.net (anthony)
Date: Sun, 27 Apr 2008 23:13:54 -0400
Subject: [sdiy] Rising Realsitic Electronic Reverb prices and the urgeto
	modify...
References: <2198741.1208915902789.JavaMail.root@mswamui-chipeau.atl.sa.earthlink.net>
Message-ID: <00ce01c8a8dd$e5aba7d0$0202a8c0@positronium>

> Did you also design the Radio Shack Stereo Synthesizer unit?

Wait. Do you mean the Archer Video Sound Processor? I buy those all the time 
on eBay. I use every part. I even have TWO heavilly modded (of course) units 
in actual use in a home theatre system ('78A's: the best version for actual 
use, although the '77 has it's merits - like a full steel chassis that works 
great for tube amps and a Reticon RD5106 and a handful of 4136's and an 
LM1894 DNR chip, etc. etc...) and I have a Pioneer receiver that has Dolby 
Prologic amongst other surround options (because I'm still too poor for a 
full fledged 5.1 or 6.1 system...). It's super-tweakable for a dork like me 
who instead of 2 or 4 good speakers has 8 middling ones and a bunch of chip 
amps from car stereos. (Soone to have a tube mono-block for my center 
channel and then maybe a stereo tube amp blah blah blah...)

I usually pass on the '78-NON-A's because they don't have the cool 
JRC4558DD's (that's right TWO D's!) and the PCB is majorly kludged - didn't 
think the grounding through ahead of time did we - with 2 DIFFERENT BBD 
clocks??? Maybe if the price is super low. Good for an MN3007 and an MN3006. 
The '78 was screaming for a redesign and I'm pretty sure that's what the 
'78A is. So I buy those and the '77's.

Counting the BBD chips I have it looks like I've gotten 8 or 9 of the '78's 
in whatever incarnation and 3 '77's. Sometimes they go for a lot and 
sometimes they don't. I always hoped I could keep 'em a secret so that 
nobody would buy 'em, but they do anyways. I mean I get email notifications 
and everything when one pops up on eBay. MN3011's too. That's how I got two 
for $0.03. Dammit I just can't stop gloating about that. Does it make you 
sick? What makes me sick is that since I have two, my designs for them 
always end up totally Byzantine: a complete modular synth just to run two 
brother-trucking multi-tapped BBD's!

Did Radio Shack ever have a unit that used MN3011's? Or MN3005's? Or even 
MN3205's for that matter???
And why the hell didn't Pansonic make an 8-pin version of the MN3004??? 
(Because I want to try replacing the MN3009's in my Roland MKS-50 and I 
think MN3007's might be too big, but maybe not... maybe if I jacked up the 
clock speeds I could get slide-whistle to go away?)

Frasier,
Anthony


> Cheers,
> Jeff
>
> -----Original Message-----
>>From: Paul Schreiber <pschreiber at sbcglobal.net>
>>Sent: Apr 22, 2008 9:37 PM
>>To: anthony <aankrom at bluemarble.net>, Synth-diy at dropmix.xs4all.nl
>>Subject: Re: [sdiy] Rising "Realsitic Electronic Reverb" prices and the 
>>urge tomodify...
>>
>>Jeez, I designed this thing in 1980 and it won't die :)
>>
>>Paul S.
>>
>>----- Original Message ----- 
>>From: "anthony" <aankrom at bluemarble.net>
>>To: <Synth-diy at dropmix.xs4all.nl>
>>Sent: Monday, April 21, 2008 1:13 PM
>>Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
>>tomodify...
>>
>>
>>> Hi guys,
>>>
>>> So I have one Realistic Electronic Reverb: the greatest effect to use 
>>> for
>>> not quite what it was intended for. This booger is a great noisemaker 
>>> and
>>> lots of fun with it's slider controls. It's even better with a few 
>>> tweaks
>>> to the circuit: more gain and high-end roll-off to the regen path, 471pF
>>> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in 
>>> place
>>> of the AN6550's, socket for the timing cap to play with different 
>>> values,
>>> adding 0.1 uF bypass caps here and there, and the latest greatest mod:
>>> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've 
>>> thought
>>> about wiring 2 or 3 in series, the BL3208A being something like $3.75 in
>>> price. Next planned mod is making the "DEPTH" control into a true 
>>> wet/dry
>>> crossfader, which is a non-trivial task, but not impossible: I think a 1
>>> uf cap and a couple 100kOhm resistors to put the bias in the right place
>>> again and cutting the traces on the PCB and rewiring accordingly.
>>>
>>> SO I've been trying to buy another one on eBay for what I got my first 
>>> one
>>> for ($12.00) and it's been a daunting task. People are catching on to 
>>> how
>>> cool these are.
>>>
>>> I'm not one to care much for collectability in gear because I like to be
>>> able to use my gear to the fullest. But I'm planning some more mods that
>>> will actuall involve cutting into the unit and I'm beginning to wonder
>>> whether I should. I wanted to add a DP3T selector switch to select 
>>> between
>>> various timing caps (if I can just find a good place on the front for a
>>> toggle switch to go...), and adding some brass body contacts to bring it
>>> (sort of) into the realm of circuit bending. I must admit that I don't
>>> actually hold to the philosphy of circuit bending although I enjoy 
>>> hearing
>>> some of the results. I don't think wiring various contacts and 
>>> capacitors
>>> to the timing cap connections could be considered circuit bending in its
>>> true spirit because they are not random bends, but carefully thought out
>>> connections. Putting your fingers across the timing cap terminals is 
>>> very
>>> fun: it depends on the pressure exerted so it has a playability factor 
>>> to
>>> it: you can quickly (or slowly) descend into the realm of 2 second 
>>> delays
>>> and back again. With the increased number of stages in the BL3208A, it's
>>> even better: repeats just go on and on without sounding like an
>>> oscillation, but it'll oscillate too - and how!
>>>
>>> So I'm wondering: should I do it? I mean even when they're going at $40 
>>> on
>>> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or
>>> something.
>>>
>>> Also, if anyone has DONE the wet/dry crossfade mod and would like to
>>> share, I'd appreciate that a lot. Thanx...
>>>
>>>
>>> Cheers,
>>> Anthony
>>>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>_______________________________________________
>>Synth-diy mailing list
>>Synth-diy at dropmix.xs4all.nl
>>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From synth1 at airmail.net  Mon Apr 28 05:18:35 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 27 Apr 2008 22:18:35 -0500
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the
	urgetomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9><01d101c8a3db$78eca880$0202a8c0@positronium><008201c8a4e2$87151890$b000a8c0@curley>
	<00cb01c8a8da$8c6cda20$0202a8c0@positronium>
Message-ID: <009201c8a8de$8c6a1e30$b000a8c0@curley>

> You're kidding? I don't care what anyone says, it's a good design. For 
> what it really does and more.
>
>>
>> Jeez, I designed this thing in 1980 and it won't die :)
>>
>> Paul S.

Nope, I did preliminary work on it when I was a co-op student at Texas A&M
and working at Tandy repairing TRS-80s and also some BBD work with Reticon.

I went back to work at Tandy starting in May 1980 and did that, a little 
'audio enhancement'
box for TVs (used National Semi's DNR [Dynamic Noise Reduction] IC,)  a "get 
around
the Orban patent" stereo filed generator combined with "couldn't get around 
the patent" BBD
HRTF [head-related transfer function] circuit which later turned into the 
patented 'Spacializer'
system for expanding the apparent stereo soundstage.

ANd then I worked on the Moog/Tandy MG-1 synth with Moog designer Rich 
Walborn.

Bet you didn't think anyone at Radio Shack knew about all this sort of stuff 
:)

Paul S.





From batzman-nr at all-electric.com  Mon Apr 28 05:35:58 2008
From: batzman-nr at all-electric.com (Batz Goodfortune)
Date: Mon, 28 Apr 2008 13:05:58 +0930
Subject: [sdiy] Cary Dies at 82
In-Reply-To: <00cb01c8a8da$8c6cda20$0202a8c0@positronium>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
	<008201c8a4e2$87151890$b000a8c0@curley>
Message-ID: <5.1.0.14.2.20080428124427.00b1bbf0@mail.all-electric.com>

Y-ellow All.
         For those who know their electronic music history, will be 
saddened to learn of the passing of Tristram Cary. He died in the Royal 
Adelaide Hospital on Thursday aged 82.

Cary was the co-founder of EMS and co inventor of the EMS VCS3 amongst 
others. Synths which a lot of people here have tried to clone in various 
ways over the years. Though his background was in classical music, he 
became one of the greatest influences in modern electronic music and his 
synthesis was responsible for the early sounds of Pink Floyd, Brian Eno, 
The who King Crimson and others. In the Adelaide electronic music scene it 
was almost impossible to move for VCS3s. The VCS3 was my first REAL synth.

Cary was born in England and became fascinated with electronically produced 
sound after spending time working as a naval radar officer during World War 
II. He was a friend of and worked with Robert Moog who at one time, was 
promoting the VCS3 in the US. Despite being in competition with EMS. He was 
also a pioneer of computer/digitally generated synthesis and together with 
his EMS colleagues, presented the first computer generated musical 
performance using a PDP8 mini computer live on stage.

I knew Tristram back in the 70s. His electronic music lab at the Elder 
Conservatorium of the Adelaide University was both legendary and awe 
inspiring. Along with everyone else who ever met him, he was one of the 
greatest influences on our music.

He will be missed. But at least he and Bob can now jam with Stockhausen, 
kick John Cage's ass and give Hendrix a run for his money for all eternity.

Be absolutely Icebox.

  _ __        _    __International Pain-in-the-Ass and prophet of doom__
| "_ \      | |
| |_)/  __ _| |_ ____       ALL ELECTRIC KITCHEN
|  _ \ / _` | __|___ |Your source of Armageddon in a musically crass world
| |_) | (_| | |_  / /
|_,__/ \__,_|\__|/ /   Disgusting-> http://all-electric.com
                 / ,__  Music-> http://all-electric.com/music_downloads.html
Goodfortune    |_____| Cult  -----> http://www.subgenius.com



From synth1 at airmail.net  Mon Apr 28 05:40:21 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 27 Apr 2008 22:40:21 -0500
Subject: [sdiy] About stereo enhancement stuff...
References: <008001c8a375$c6fed630$8501a8c0@ice9><01d101c8a3db$78eca880$0202a8c0@positronium><008201c8a4e2$87151890$b000a8c0@curley><00cb01c8a8da$8c6cda20$0202a8c0@positronium>
	<009201c8a8de$8c6a1e30$b000a8c0@curley>
Message-ID: <009b01c8a8e1$95f50570$b000a8c0@curley>

Much later (early 1990) I also worked on another type of algorithm that 
evolved into 'Q-Sound'
which was first used on the 'Robin Hood' movie with Kevin Costner. It was 
only 'turned on' when
they shot the arrows with 'Arrow CAM' (the camera angle was like you were 
rding on top of the arrow).

http://www.qsound.com/demos/3d-audio.htm

This is more of a DSP thing :) I never used it at Tandy because at the time 
the DSPs were all discrete bit-slice
monsters that were about $5K of hardware, I was looking at a full custom 
ASIC (like what Q-Sound sells now)
I called the Wendy Processor (wonder where that name came from) that I was 
doing in conjunction with
Kurzweil (they had a 2 chip ROMpler set called Calvin and Hobbs they were 
testing the OEM marketplace with).

That was too $$$, I then called old synth buddy Dave Rossum at EMu and tried 
him to sell me the 'G Chip' ASIC
used in the Proteus stuff and that was were I was headed but RS nixed that, 
too.

I tried to get this technology in the Tandy Sensation, the world's first 
true multimedia PC (I was one of the
authors of the MPC specification and later worked on the AC97 codec spec 
with Microsoft) but true to Radio Shack nature, they would not give me
a $25/computer budget + $500K NRE to do it :(  I was also pressing Yamaha to 
sell me the ICs used in the
TX802 but they were not interested. So I worked on graphics cards.

Paul S.



From synth1 at airmail.net  Mon Apr 28 06:01:26 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Sun, 27 Apr 2008 23:01:26 -0500
Subject: [sdiy] Chinese MG-1s??!?
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
	<008201c8a4e2$87151890$b000a8c0@curley>
	<00cb01c8a8da$8c6cda20$0202a8c0@positronium>
	<009201c8a8de$8c6a1e30$b000a8c0@curley>
	<1dc7c5a0804272055x6601e68fwcd776a82ae455d52@mail.gmail.com>
Message-ID: <00c801c8a8e4$88351850$b000a8c0@curley>

So how about it Paul?  Could Behringer pull of something comparable to the 
MG-1?

a) there is no patents in the MG-1 that are still current. So, the is no 
legal reason not to build them again. In fact, you could build any synth up 
to 1991 vintage
and not get into legal trouble except for cosmetics (as long as you didn't 
exactly copy the panel layput, graphics, etc).
b) the circuitry is not the 'hard part', it's the mechanical stuff 
(case/keyboard/etc).
c) you could put all the TOG IC stuff in a $1 ASIC :)

Paul S.



From tu at alphalink.com.au  Mon Apr 28 06:40:56 2008
From: tu at alphalink.com.au (Tristan Upton)
Date: Mon, 28 Apr 2008 14:10:56 +0930
Subject: [sdiy] Chinese MG-1s??!?
In-Reply-To: <00c801c8a8e4$88351850$b000a8c0@curley>
References: <008001c8a375$c6fed630$8501a8c0@ice9>
	<01d101c8a3db$78eca880$0202a8c0@positronium>
	<008201c8a4e2$87151890$b000a8c0@curley>
	<00cb01c8a8da$8c6cda20$0202a8c0@positronium>
	<009201c8a8de$8c6a1e30$b000a8c0@curley>
	<1dc7c5a0804272055x6601e68fwcd776a82ae455d52@mail.gmail.com>
	<00c801c8a8e4$88351850$b000a8c0@curley>
Message-ID: <20080428044056.9A150F403C@mail01.chariot.net.au>

Behringer works on high volumes and low margins. I doubt they would be 
interested unless they could shift thousands of units each month. How much 
market demand is there for a cheap analog synth? 

/Tristan 

Paul Schreiber writes: 

> So how about it Paul?  Could Behringer pull of something comparable to the 
> MG-1? 
> 
> a) there is no patents in the MG-1 that are still current. So, the is no 
> legal reason not to build them again. In fact, you could build any synth 
> up to 1991 vintage
> and not get into legal trouble except for cosmetics (as long as you didn't 
> exactly copy the panel layput, graphics, etc).
> b) the circuitry is not the 'hard part', it's the mechanical stuff 
> (case/keyboard/etc).
> c) you could put all the TOG IC stuff in a $1 ASIC :) 
> 
> Paul S. 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


From lanterma at ece.gatech.edu  Mon Apr 28 07:16:08 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 28 Apr 2008 01:16:08 -0400
Subject: [sdiy] CA3140 vs. TL08x, LM319 vs LM311 in Bergfotron/Buchla VCO
Message-ID: <A41F0BB0-CE1F-49E8-AA58-E2F4B5E36524@ece.gatech.edu>

While we're on the topic of the Bergfotron/Buchla triangle core...

If the TL08x is good in the integrator because of its high input  
impedance, would a CA3140 work even better? (I recall seeing the  
CA3140 in some sawtooth designs, maybe the various Electronotes  
designs?)

Also, I've heard the LM319 is faster than the LM311 - would it work  
better in this application to? (And the 319 is kind of nice since it  
has two of them, so it would be natural if you were building a dual  
VCO - and the CA3140 has a dual version, the CA3240).

- Aaron

P.S. I'm pretty sure my student Greg was using a TL08x or TL07x as his  
integrator - I have giant tubes full of them - so I'm guessing there's  
something else going on with the wiring...


From Florian.Anwander at consol.de  Mon Apr 28 11:19:25 2008
From: Florian.Anwander at consol.de (Florian Anwander)
Date: Mon, 28 Apr 2008 11:19:25 +0200
Subject: [sdiy] Chinese MG-1s??!?
In-Reply-To: <20080428044056.9A150F403C@mail01.chariot.net.au>
References: <008001c8a375$c6fed630$8501a8c0@ice9>	<01d101c8a3db$78eca880$0202a8c0@positronium>	<008201c8a4e2$87151890$b000a8c0@curley>	<00cb01c8a8da$8c6cda20$0202a8c0@positronium>	<009201c8a8de$8c6a1e30$b000a8c0@curley>	<1dc7c5a0804272055x6601e68fwcd776a82ae455d52@mail.gmail.com>	<00c801c8a8e4$88351850$b000a8c0@curley>
	<20080428044056.9A150F403C@mail01.chariot.net.au>
Message-ID: <4815969D.8060802@consol.de>

Hi Tristan

> Behringer works on high volumes and low margins. I doubt they would be 
> interested unless they could shift thousands of units each month. How 
> much market demand is there for a cheap analog synth?
Thats true. I ask myself whether Behringer did ever try to buy in 
Quasimidi - they would have been the perfect synth departement for 
Behringer.

Florian


From aankrom at bluemarble.net  Mon Apr 28 13:30:13 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 07:30:13 -0400
Subject: [sdiy] Chinese MG-1s??!?
References: <008001c8a375$c6fed630$8501a8c0@ice9><01d101c8a3db$78eca880$0202a8c0@positronium><008201c8a4e2$87151890$b000a8c0@curley><00cb01c8a8da$8c6cda20$0202a8c0@positronium><009201c8a8de$8c6a1e30$b000a8c0@curley><1dc7c5a0804272055x6601e68fwcd776a82ae455d52@mail.gmail.com>
	<00c801c8a8e4$88351850$b000a8c0@curley>
Message-ID: <00dd01c8a923$3bef09d0$0202a8c0@positronium>

The circuitry is pretty trivial in the MG-1 - when taken a section at a 
time. There's just quite a bit of it. But even then, much less than many 
other synths. The filter is what makes the MG-1 golden.

> So how about it Paul?  Could Behringer pull of something comparable to the 
> MG-1?
>
> a) there is no patents in the MG-1 that are still current. So, the is no 
> legal reason not to build them again. In fact, you could build any synth 
> up to 1991 vintage
> and not get into legal trouble except for cosmetics (as long as you didn't 
> exactly copy the panel layput, graphics, etc).
> b) the circuitry is not the 'hard part', it's the mechanical stuff 
> (case/keyboard/etc).
> c) you could put all the TOG IC stuff in a $1 ASIC :)
>
> Paul S.
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From aankrom at bluemarble.net  Mon Apr 28 13:44:08 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 07:44:08 -0400
Subject: [sdiy] Rising Realsitic Electronic Reverb prices and the
	urgetomodify...
References: <2198741.1208915902789.JavaMail.root@mswamui-chipeau.atl.sa.earthlink.net>
	<00ce01c8a8dd$e5aba7d0$0202a8c0@positronium>
Message-ID: <00e801c8a925$2d428f40$0202a8c0@positronium>

Another quick note on these, the "Stereo Synthesizer" is an elegant 2-stage 
notch filter. If you use 1% or 2% tolerance caps & trimmers in these notch 
filters, you can make the notches really sharp. And if you have two units 
you can make those notches come at 4 different frequencies (along with being 
able to have two different delays on the L-R "pseudo-surround" channels, 
even making one R-L if you wanted - only the '78s had these ouputs though - 
the '77 only had the sound field enhancer, which is pretty cool too, 
particularly if you're listening to an "overly stereo" album mix...)

I wish the LM1894 had caught on much more in other applications so that they 
would be more ubiquitous.
I'm still trying to make this group into converts over the compander system: 
you can run a small signal into the BBD input and add all the gain you want 
after the noise reduction. You have to use the input sound to control the 
filter via the sidechain (and you have to slam the gain on the sidechain if 
you don't use the summing amp) - but that's not too far from the same 
disciplines involved in complicated compressor/expander systems anyway.

Still, kudos to Paul Schreiber for convincing Tandy to go for a chip that 
needed licensing to use.

Seinfeld,
Anthony


>> Did you also design the Radio Shack Stereo Synthesizer unit?
>
> Wait. Do you mean the Archer Video Sound Processor? I buy those all the 
> time on eBay. I use every part. I even have TWO heavilly modded (of 
> course) units in actual use in a home theatre system ('78A's: the best 
> version for actual use, although the '77 has it's merits - like a full 
> steel chassis that works great for tube amps and a Reticon RD5106 and a 
> handful of 4136's and an LM1894 DNR chip, etc. etc...) and I have a 
> Pioneer receiver that has Dolby Prologic amongst other surround options 
> (because I'm still too poor for a full fledged 5.1 or 6.1 system...). It's 
> super-tweakable for a dork like me who instead of 2 or 4 good speakers has 
> 8 middling ones and a bunch of chip amps from car stereos. (Soone to have 
> a tube mono-block for my center channel and then maybe a stereo tube amp 
> blah blah blah...)
>
> I usually pass on the '78-NON-A's because they don't have the cool 
> JRC4558DD's (that's right TWO D's!) and the PCB is majorly kludged - 
> didn't think the grounding through ahead of time did we - with 2 DIFFERENT 
> BBD clocks??? Maybe if the price is super low. Good for an MN3007 and an 
> MN3006. The '78 was screaming for a redesign and I'm pretty sure that's 
> what the '78A is. So I buy those and the '77's.
>
> Counting the BBD chips I have it looks like I've gotten 8 or 9 of the 
> '78's in whatever incarnation and 3 '77's. Sometimes they go for a lot and 
> sometimes they don't. I always hoped I could keep 'em a secret so that 
> nobody would buy 'em, but they do anyways. I mean I get email 
> notifications and everything when one pops up on eBay. MN3011's too. 
> That's how I got two for $0.03. Dammit I just can't stop gloating about 
> that. Does it make you sick? What makes me sick is that since I have two, 
> my designs for them always end up totally Byzantine: a complete modular 
> synth just to run two brother-trucking multi-tapped BBD's!
>
> Did Radio Shack ever have a unit that used MN3011's? Or MN3005's? Or even 
> MN3205's for that matter???
> And why the hell didn't Pansonic make an 8-pin version of the MN3004??? 
> (Because I want to try replacing the MN3009's in my Roland MKS-50 and I 
> think MN3007's might be too big, but maybe not... maybe if I jacked up the 
> clock speeds I could get slide-whistle to go away?)
>
> Frasier,
> Anthony
>
>
>> Cheers,
>> Jeff
>>
>> -----Original Message-----
>>>From: Paul Schreiber <pschreiber at sbcglobal.net>
>>>Sent: Apr 22, 2008 9:37 PM
>>>To: anthony <aankrom at bluemarble.net>, Synth-diy at dropmix.xs4all.nl
>>>Subject: Re: [sdiy] Rising "Realsitic Electronic Reverb" prices and the 
>>>urge tomodify...
>>>
>>>Jeez, I designed this thing in 1980 and it won't die :)
>>>
>>>Paul S.
>>>
>>>----- Original Message ----- 
>>>From: "anthony" <aankrom at bluemarble.net>
>>>To: <Synth-diy at dropmix.xs4all.nl>
>>>Sent: Monday, April 21, 2008 1:13 PM
>>>Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the urge
>>>tomodify...
>>>
>>>
>>>> Hi guys,
>>>>
>>>> So I have one Realistic Electronic Reverb: the greatest effect to use 
>>>> for
>>>> not quite what it was intended for. This booger is a great noisemaker 
>>>> and
>>>> lots of fun with it's slider controls. It's even better with a few 
>>>> tweaks
>>>> to the circuit: more gain and high-end roll-off to the regen path, 
>>>> 471pF
>>>> polytsyrene caps in place of the ceramic ones, JRC4558DD op amps in 
>>>> place
>>>> of the AN6550's, socket for the timing cap to play with different 
>>>> values,
>>>> adding 0.1 uF bypass caps here and there, and the latest greatest mod:
>>>> popping in a BL3208A (normal 8-pin!) from Small Bear and WOW! I've 
>>>> thought
>>>> about wiring 2 or 3 in series, the BL3208A being something like $3.75 
>>>> in
>>>> price. Next planned mod is making the "DEPTH" control into a true 
>>>> wet/dry
>>>> crossfader, which is a non-trivial task, but not impossible: I think a 
>>>> 1
>>>> uf cap and a couple 100kOhm resistors to put the bias in the right 
>>>> place
>>>> again and cutting the traces on the PCB and rewiring accordingly.
>>>>
>>>> SO I've been trying to buy another one on eBay for what I got my first 
>>>> one
>>>> for ($12.00) and it's been a daunting task. People are catching on to 
>>>> how
>>>> cool these are.
>>>>
>>>> I'm not one to care much for collectability in gear because I like to 
>>>> be
>>>> able to use my gear to the fullest. But I'm planning some more mods 
>>>> that
>>>> will actuall involve cutting into the unit and I'm beginning to wonder
>>>> whether I should. I wanted to add a DP3T selector switch to select 
>>>> between
>>>> various timing caps (if I can just find a good place on the front for a
>>>> toggle switch to go...), and adding some brass body contacts to bring 
>>>> it
>>>> (sort of) into the realm of circuit bending. I must admit that I don't
>>>> actually hold to the philosphy of circuit bending although I enjoy 
>>>> hearing
>>>> some of the results. I don't think wiring various contacts and 
>>>> capacitors
>>>> to the timing cap connections could be considered circuit bending in 
>>>> its
>>>> true spirit because they are not random bends, but carefully thought 
>>>> out
>>>> connections. Putting your fingers across the timing cap terminals is 
>>>> very
>>>> fun: it depends on the pressure exerted so it has a playability factor 
>>>> to
>>>> it: you can quickly (or slowly) descend into the realm of 2 second 
>>>> delays
>>>> and back again. With the increased number of stages in the BL3208A, 
>>>> it's
>>>> even better: repeats just go on and on without sounding like an
>>>> oscillation, but it'll oscillate too - and how!
>>>>
>>>> So I'm wondering: should I do it? I mean even when they're going at $40 
>>>> on
>>>> eBay, it's not like I'm talking about circuit bending an Ibanez FL9 or
>>>> something.
>>>>
>>>> Also, if anyone has DONE the wet/dry crossfade mod and would like to
>>>> share, I'd appreciate that a lot. Thanx...
>>>>
>>>>
>>>> Cheers,
>>>> Anthony
>>>>
>>>> _______________________________________________
>>>> Synth-diy mailing list
>>>> Synth-diy at dropmix.xs4all.nl
>>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>>
>>>_______________________________________________
>>>Synth-diy mailing list
>>>Synth-diy at dropmix.xs4all.nl
>>>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From pfperry at melbpc.org.au  Mon Apr 28 14:33:53 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Mon, 28 Apr 2008 22:33:53 +1000
Subject: [sdiy] Using audio to trigger CMOS
Message-ID: <006b01c8a92c$1ef58080$8501a8c0@ice9>

A 555 timer rigged as a one-shot might be useful here.

paul perry Melbourne Australia

-----Original Message-----


I'm hoping for some help refining a circuit I'm working on that uses an
audio signal as a clock to trigger a 4024 Ripple Counter.

The audio signal is a 1/16th note sequence that is meant to represent a
square wave i.e. Note On = High (or Mark), Note Off = Low (or Space).

I've got a prototype that uses an AC Coupled gain stage to take the audio
input and feeds it into a comparator.

The current version works(ish) minus some problems which I think are down to
some ac coupling mistakes and a lack of headroom on my power supply - all of
which I think I can sort - but I was wondering if there also needs to be any
type of rectification between the gain stage and the comparator?

I can be pretty specific about the type of audio signal that goes in (I'm
currently using a PWM square wave with a 90/10 mark/space ratio at a fairly
high pitch - which I figured would give the greatest ratio of High to Low
signal when the Note was 'on') - I'm not expecting to get a square wave
trigger out of a guitar input for example - but I'd like the circuit to be
as safe and reliable as possible.




From jpdesroc at oricom.ca  Mon Apr 28 15:03:03 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Mon, 28 Apr 2008 09:03:03 -0400
Subject: [sdiy] COSMO knobs type 7603 for sale??
Message-ID: <380-2200841281333449@oricom.ca>


Hi list,
Does anybody have COSMO knobs type 7603 (not 7602)
like the Moog 921B VCO module 'Frequency' control
see picture http://www.siliconbreakdown.com/moog55.html
for sale? They have 1.25" base diameter.
I'd need 15 of them.
Please email me at jpdesroc at oricom.ca
Thanks




From juzowen at googlemail.com  Mon Apr 28 15:07:21 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Mon, 28 Apr 2008 13:07:21 +0000
Subject: [sdiy] Using audio to trigger CMOS
Message-ID: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>

Hey all,

I'm hoping for some help refining a circuit I'm working on that uses an audio signal as a clock to trigger a 4024 Ripple Counter.

The audio signal is a 1/16th note sequence that is meant to represent a square wave i.e. Note On = High (or Mark), Note Off = Low (or Space).

I've got a prototype that uses an AC Coupled gain stage to take the audio input and feeds it into a comparator.

The current version works(ish) minus some problems which I think are down to some ac coupling mistakes and a lack of headroom on my power supply - all of which I think I can sort - but I was wondering if there also needs to be any type of rectification between the gain stage and the comparator?

I can be pretty specific about the type of audio signal that goes in (I'm currently using a PWM square wave with a 90/10 mark/space ratio at a fairly high pitch - which I figured would give the greatest ratio of High to Low signal when the Note was 'on') - I'm not expecting to get a square wave trigger out of a guitar input for example - but I'd like the circuit to be as safe and reliable as possible.

Any advice? Appreciated as always

J




From rtellason at verizon.net  Mon Apr 28 15:34:06 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Mon, 28 Apr 2008 09:34:06 -0400
Subject: [sdiy] Using audio to trigger CMOS
In-Reply-To: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
References: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
Message-ID: <200804280934.07076.rtellason@verizon.net>

On Monday 28 April 2008 09:07, Justin Owen wrote:
> Hey all,
>
> I'm hoping for some help refining a circuit I'm working on that uses an
> audio signal as a clock to trigger a 4024 Ripple Counter.
>
> The audio signal is a 1/16th note sequence that is meant to represent a
> square wave i.e. Note On = High (or Mark), Note Off = Low (or Space).
>
> I've got a prototype that uses an AC Coupled gain stage to take the audio
> input and feeds it into a comparator.
>
> The current version works(ish) minus some problems which I think are down
> to some ac coupling mistakes and a lack of headroom on my power supply -
> all of which I think I can sort - but I was wondering if there also needs
> to be any type of rectification between the gain stage and the comparator?
>
> I can be pretty specific about the type of audio signal that goes in (I'm
> currently using a PWM square wave with a 90/10 mark/space ratio at a fairly
> high pitch - which I figured would give the greatest ratio of High to Low
> signal when the Note was 'on') - I'm not expecting to get a square wave
> trigger out of a guitar input for example - but I'd like the circuit to be
> as safe and reliable as possible.

Seems to me you could get plenty of triggering signal by simply running a CMOS 
inverter or two in linear mode.  AC couple the input if you need to,  have an 
input resistor and a feedback resistor like you would for op amps (ratio sets 
the gain),  and you could even if necessary inject a little bit of DC biasing 
into the input after the coupling cap to affect your response.  Check it out 
in Don Lancaster's CMOS Cookbook,  I'm pretty sure he covers that...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From harrybissell at wowway.com  Mon Apr 28 16:50:24 2008
From: harrybissell at wowway.com (harrybissell at wowway.com)
Date: Mon, 28 Apr 2008 09:50:24 -0500
Subject: [sdiy] Using audio to trigger CMOS
In-Reply-To: <006b01c8a92c$1ef58080$8501a8c0@ice9>
References: <006b01c8a92c$1ef58080$8501a8c0@ice9>
Message-ID: <20080428144445.M20604@wowway.com>

Are you trying to trigger on a note event, or to divide a frequency?

If it is a frequency, check out any of the "octave pedal" schematics
such as Boss, Roland, DOD etc...  

H^) harry




On Mon, 28 Apr 2008 22:33:53 +1000, Paul Perry wrote
> A 555 timer rigged as a one-shot might be useful here.
> 
> paul perry Melbourne Australia
> 
> -----Original Message-----
> 
> I'm hoping for some help refining a circuit I'm working on that uses 
> an audio signal as a clock to trigger a 4024 Ripple Counter.
> 
> The audio signal is a 1/16th note sequence that is meant to 
> represent a square wave i.e. Note On = High (or Mark), Note Off = 
> Low (or Space).
> 
> I've got a prototype that uses an AC Coupled gain stage to take the audio
> input and feeds it into a comparator.
> 
> The current version works(ish) minus some problems which I think are 
> down to some ac coupling mistakes and a lack of headroom on my power 
> supply - all of which I think I can sort - but I was wondering if 
> there also needs to be any type of rectification between the gain 
> stage and the comparator?
> 
> I can be pretty specific about the type of audio signal that goes in 
> (I'm currently using a PWM square wave with a 90/10 mark/space ratio 
> at a fairly high pitch - which I figured would give the greatest 
> ratio of High to Low signal when the Note was 'on') - I'm not 
> expecting to get a square wave trigger out of a guitar input for 
> example - but I'd like the circuit to be as safe and reliable as possible.
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva



From ijfritz at comcast.net  Mon Apr 28 17:40:29 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Mon, 28 Apr 2008 09:40:29 -0600
Subject: [sdiy] Buchla-Bergfotron VCO
Message-ID: <6.2.1.2.2.20080428092947.020cd990@mail.comcast.net>

Hello --

Can anyone tell me why the 5.1k resistors are even there?  It seems to me 
they just cause common-mode and offset problems.

In my triangle VCO I just fix the top of the mirrors at 2V (to keep 
everything out of saturation).  With an accurate and *symmetrical* current 
mirror the waveform symmetry at high frequency is fine.

Any triangle VCO will eventually fail at low frequency because of the input 
bias current of the integrator.  To see where the errors are significant, 
just look up the bias current  and compare it to the control current vs 
frequency.  An easy enough calculation.  This bias error is easily 
compensated with the usual offset trimming technique.

   Ian



From aankrom at bluemarble.net  Mon Apr 28 18:49:55 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 12:49:55 -0400
Subject: [sdiy] Using audio to trigger CMOS
References: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
Message-ID: <00f501c8a94f$e4f3c2b0$0202a8c0@positronium>

Ray Wilson has a circuit on his Music From Outer Space website that I think 
would do what you want.

I'll describe a simple circuit that I would try: use an opamp like a TL071 
or TL081 (or TL082, etc...) with a fair amount of gain (put in a pot to 
adjust maybe) and then connect the output to a Schmitt trigger like a 40106, 
4584 or even a 4093 connected like an inverter (both inputs tied together), 
and then run in through a second stage so it's positive again.

I can't remember if this is one of those situations where you want to run 
the opamp from a bipolar supply and power the CMOS gate by tying VDD (+) to 
ground and VSS (-) to the -15V (or whatever you're using) rail. I do know 
it'll work that way anyway. Don't know if you NEED to do it that way...

The Carol Burnett Show,
Anthony

----- Original Message ----- 
From: "Justin Owen" <juzowen at googlemail.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 28, 2008 9:07 AM
Subject: [sdiy] Using audio to trigger CMOS


> Hey all,
>
> I'm hoping for some help refining a circuit I'm working on that uses an 
> audio signal as a clock to trigger a 4024 Ripple Counter.
>
> The audio signal is a 1/16th note sequence that is meant to represent a 
> square wave i.e. Note On = High (or Mark), Note Off = Low (or Space).
>
> I've got a prototype that uses an AC Coupled gain stage to take the audio 
> input and feeds it into a comparator.
>
> The current version works(ish) minus some problems which I think are down 
> to some ac coupling mistakes and a lack of headroom on my power supply - 
> all of which I think I can sort - but I was wondering if there also needs 
> to be any type of rectification between the gain stage and the comparator?
>
> I can be pretty specific about the type of audio signal that goes in (I'm 
> currently using a PWM square wave with a 90/10 mark/space ratio at a 
> fairly high pitch - which I figured would give the greatest ratio of High 
> to Low signal when the Note was 'on') - I'm not expecting to get a square 
> wave trigger out of a guitar input for example - but I'd like the circuit 
> to be as safe and reliable as possible.
>
> Any advice? Appreciated as always
>
> J
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From jason at redfish.net  Mon Apr 28 19:12:31 2008
From: jason at redfish.net (Jason Proctor)
Date: Mon, 28 Apr 2008 10:12:31 -0700
Subject: [sdiy] Using audio to trigger CMOS
In-Reply-To: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
References: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
Message-ID: <a06200732c43bb49177f3@[10.0.1.201]>

sounds like a job for an envelope follower with gate. IIRC, the fine 
Oakley implementation of this involves a rectifier feeding a 
comparator with a variable threshold. there's variable lag on the 
output of the rectifier too so that the comparator doesn't flap all 
the time if the input signal varies a lot in amplitude.

when i had one, it worked like a charm.

hth

>Hey all,
>
>I'm hoping for some help refining a circuit I'm working on that uses 
>an audio signal as a clock to trigger a 4024 Ripple Counter.
>
>The audio signal is a 1/16th note sequence that is meant to 
>represent a square wave i.e. Note On = High (or Mark), Note Off = 
>Low (or Space).
>
>I've got a prototype that uses an AC Coupled gain stage to take the 
>audio input and feeds it into a comparator.
>
>The current version works(ish) minus some problems which I think are 
>down to some ac coupling mistakes and a lack of headroom on my power 
>supply - all of which I think I can sort - but I was wondering if 
>there also needs to be any type of rectification between the gain 
>stage and the comparator?
>
>I can be pretty specific about the type of audio signal that goes in 
>(I'm currently using a PWM square wave with a 90/10 mark/space ratio 
>at a fairly high pitch - which I figured would give the greatest 
>ratio of High to Low signal when the Note was 'on') - I'm not 
>expecting to get a square wave trigger out of a guitar input for 
>example - but I'd like the circuit to be as safe and reliable as 
>possible.
>
>Any advice? Appreciated as always
>
>J
>
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From aankrom at bluemarble.net  Mon Apr 28 19:40:40 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 13:40:40 -0400
Subject: [sdiy] Using audio to trigger CMOS
References: <4815bdfb.0cba5e0a.79ed.6f93@mx.google.com>
	<a06200732c43bb49177f3@[10.0.1.201]>
Message-ID: <00fc01c8a956$fbe04640$0202a8c0@positronium>

The Polyfusion Envelope Follower is similar, having the variable threshold, 
but no lag. It's an easy circuit though. I've built one: it's great for 
using guitar signals to trigger, well, just about anything.

----- Original Message ----- 
From: "Jason Proctor" <jason at redfish.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 28, 2008 1:12 PM
Subject: Re: [sdiy] Using audio to trigger CMOS


> sounds like a job for an envelope follower with gate. IIRC, the fine 
> Oakley implementation of this involves a rectifier feeding a comparator 
> with a variable threshold. there's variable lag on the output of the 
> rectifier too so that the comparator doesn't flap all the time if the 
> input signal varies a lot in amplitude.
>
> when i had one, it worked like a charm.
>
> hth
>
>>Hey all,
>>
>>I'm hoping for some help refining a circuit I'm working on that uses an 
>>audio signal as a clock to trigger a 4024 Ripple Counter.
>>
>>The audio signal is a 1/16th note sequence that is meant to represent a 
>>square wave i.e. Note On = High (or Mark), Note Off = Low (or Space).
>>
>>I've got a prototype that uses an AC Coupled gain stage to take the audio 
>>input and feeds it into a comparator.
>>
>>The current version works(ish) minus some problems which I think are down 
>>to some ac coupling mistakes and a lack of headroom on my power supply - 
>>all of which I think I can sort - but I was wondering if there also needs 
>>to be any type of rectification between the gain stage and the comparator?
>>
>>I can be pretty specific about the type of audio signal that goes in (I'm 
>>currently using a PWM square wave with a 90/10 mark/space ratio at a 
>>fairly high pitch - which I figured would give the greatest ratio of High 
>>to Low signal when the Note was 'on') - I'm not expecting to get a square 
>>wave trigger out of a guitar input for example - but I'd like the circuit 
>>to be as safe and reliable as possible.
>>
>>Any advice? Appreciated as always
>>
>>J
>>
>>
>>_______________________________________________
>>Synth-diy mailing list
>>Synth-diy at dropmix.xs4all.nl
>>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From samppa.tolvanen at gmail.com  Mon Apr 28 22:54:31 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Mon, 28 Apr 2008 23:54:31 +0300
Subject: [sdiy] COSMO knobs type 7603 for sale??
In-Reply-To: <380-2200841281333449@oricom.ca>
References: <380-2200841281333449@oricom.ca>
Message-ID: <fa1b0bd80804281354s71c760a3w5a6ca6360100d02a@mail.gmail.com>

On 4/28/08, jpdesroc at oricom.ca <jpdesroc at oricom.ca> wrote:
>
>  Hi list,
>  Does anybody have COSMO knobs type 7603 (not 7602)
>  like the Moog 921B VCO module 'Frequency' control
>  see picture http://www.siliconbreakdown.com/moog55.html
>  for sale? They have 1.25" base diameter.
>  I'd need 15 of them.

Yes, We do have them. Everybody has them.

I'm willing to split for 3,5E each. Mkay, do You read me? That's 250e
for 10 as I have to check chinese eBay actions for these.

mkay, send me Your paypal, so I can be sure, You're a willing buyer.

mkay, Samppa


From juzowen at googlemail.com  Mon Apr 28 23:18:37 2008
From: juzowen at googlemail.com (Justin Owen)
Date: Mon, 28 Apr 2008 21:18:37 +0000
Subject: [sdiy] Using audio to trigger CMOS
Message-ID: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>

Thanks to everyone that's chipped in on this - much appreciated.

I think the first - and maybe the biggest - problem is getting enough gain from the input signal. I was hoping to get this running on a 9 volt single supply - and it seems like the most I've been able to coax out of an op-amp configured as an AC Coupled inverting gain stage is just under 1 volt of gain - so basically 0.01 volts at Note Off and just under 1 volt at Note On.

I did look at some Envelope Follower schems (and the Polyfusion schem has given me some clues) - but I was hoping for something alot simpler as this really just needs to convert a particular type of audio signal into a gate/trigger. (Although maybe I've underestimated how simple this should be...)

Roy and Anthony's suggestion about using a Hex Inverter in Linear mode is cool - will try that and see what goes.

Paul - Your suggestion about using a 555 one shot was also v. helpful - but it would mean re-jigging the way I have the rest of the clock set up - so at the moment, I'd like to try and solve this current set of problems. Always good to have a Plan B.

Harry - Yeah, Ideally I'm looking to get Note On and Note Off (pitch doesn't matter - it's the timing/on/off part I need)

Since I'm still a little stumped on this - any more input would surely be welcomed.

Thanks again to those who've helped out.

J






From richard.e.johnson at gmail.com  Tue Apr 29 00:44:30 2008
From: richard.e.johnson at gmail.com (Richard Johnson)
Date: Mon, 28 Apr 2008 18:44:30 -0400
Subject: [sdiy] Using audio to trigger CMOS
In-Reply-To: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>
References: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>
Message-ID: <be8b34180804281544x6cb07842h14e3dfc118fb139f@mail.gmail.com>

Justin,

I should be shot for even attempting to suggest. I'm only a
theoretical DIYer at the moment.  :)

Ironically, I've been heading down a very similar path as you in terms
of using a guitar pickup for triggering some very simple 9VDC
circuits.

What you might look into is using a diode and a capacitor exactly the
way an AM "crystal" radio does (really! just a diode, capacitor and a
resistor). That way the waveform of the timbre/pitch would be filtered
out and you'd be left with a curve that is the overall playing
dynamics of the pickup.

See an AM demodulator at the bottom of this page:
http://www.electronics-radio.com/articles/radio/modulation/amplitude_modulation/am.php

Once you have that, you should be able to use a 555 timer, op-amp,
comparator or really any adujstable-threshold Schmitt trigger circuit
to find the "plucks" of the string. Make sure that whatever you do,
there's a "Schmitt" element to keep from getting a mess of Note Ons at
each pluck of the string.

LIST: Feel free to smack me down. :)

Ric

On Mon, Apr 28, 2008 at 5:18 PM, Justin Owen <juzowen at googlemail.com> wrote:
> Thanks to everyone that's chipped in on this - much appreciated.
>
>  I think the first - and maybe the biggest - problem is getting enough gain from the input signal. I was hoping to get this running on a 9 volt single supply - and it seems like the most I've been able to coax out of an op-amp configured as an AC Coupled inverting gain stage is just under 1 volt of gain - so basically 0.01 volts at Note Off and just under 1 volt at Note On.
>
>  I did look at some Envelope Follower schems (and the Polyfusion schem has given me some clues) - but I was hoping for something alot simpler as this really just needs to convert a particular type of audio signal into a gate/trigger. (Although maybe I've underestimated how simple this should be...)
>
>  Roy and Anthony's suggestion about using a Hex Inverter in Linear mode is cool - will try that and see what goes.
>
>  Paul - Your suggestion about using a 555 one shot was also v. helpful - but it would mean re-jigging the way I have the rest of the clock set up - so at the moment, I'd like to try and solve this current set of problems. Always good to have a Plan B.
>
>  Harry - Yeah, Ideally I'm looking to get Note On and Note Off (pitch doesn't matter - it's the timing/on/off part I need)
>
>  Since I'm still a little stumped on this - any more input would surely be welcomed.
>
>  Thanks again to those who've helped out.
>
>
>
>  J
>
>
>
>
>  _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From aankrom at bluemarble.net  Tue Apr 29 01:34:22 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 19:34:22 -0400
Subject: [sdiy] Rising "Realsitic Electronic Reverb" prices and the
	urgetomodify...
References: <008001c8a375$c6fed630$8501a8c0@ice9><01d101c8a3db$78eca880$0202a8c0@positronium><008201c8a4e2$87151890$b000a8c0@curley>
	<00cb01c8a8da$8c6cda20$0202a8c0@positronium>
	<009201c8a8de$8c6a1e30$b000a8c0@curley>
Message-ID: <010c01c8a988$656a70a0$0202a8c0@positronium>

Oh and kudos for using those bitchin' Alps toggle switches (DPDT & DP3T) 
which are the same ones that the Minimoog or one other or more of the Norlin 
Moogs used. Probably the MG-1 too.

>> You're kidding? I don't care what anyone says, it's a good design. For 
>> what it really does and more.
>>
>>>
>>> Jeez, I designed this thing in 1980 and it won't die :)
>>>
>>> Paul S.
>
> Nope, I did preliminary work on it when I was a co-op student at Texas A&M
> and working at Tandy repairing TRS-80s and also some BBD work with 
> Reticon.
>
> I went back to work at Tandy starting in May 1980 and did that, a little 
> 'audio enhancement'
> box for TVs (used National Semi's DNR [Dynamic Noise Reduction] IC,)  a 
> "get around
> the Orban patent" stereo filed generator combined with "couldn't get 
> around the patent" BBD
> HRTF [head-related transfer function] circuit which later turned into the 
> patented 'Spacializer'
> system for expanding the apparent stereo soundstage.
>
> ANd then I worked on the Moog/Tandy MG-1 synth with Moog designer Rich 
> Walborn.
>
> Bet you didn't think anyone at Radio Shack knew about all this sort of 
> stuff :)
>
> Paul S.
>
>
>
>
> 




From lanterma at ece.gatech.edu  Tue Apr 29 04:19:50 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Mon, 28 Apr 2008 22:19:50 -0400
Subject: [sdiy] Fwd: SDIY list troubles
References: <48166E04.10707@gatech.edu>
Message-ID: <5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>

Howdy - My student Adam is trying a different oscillator now and  
having trouble both with the oscillator and posting to the list, so  
I'm forwarding it for him...

- Aaron

P.S. We're using a TL08x/TL07x series op amp.

------------------

The message:

Hey everyone.  I'm building the exponential V-F oscillator in figure 1  
of this app note:  http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/AN-299.pdf 
, and once again I'm getting no oscillations at the output, even after  
putting it through a TL072 buffer and inverting amp to boost it.  We  
took DC voltage readings at a bunch of points in the circuit at 0V  
input  and 15V of input to see if they changed right.  One thing I  
noticed is that the Vbe of Q1 is  changing, so the current from Q1  
_should_ be varying exponentially like it's supposed to.  I put an  
ammeter between the emitter of Q1 and the inverting input of A1 and  
saw no current, but  Aaron told me that can be pretty unreliable.

Anyway, listed below are the DC voltages we measured while  
experimenting with the circuit. Can anyone see any reasons why this  
isn't working?

Node                               Vdc at 0V input               Vdc  
at 15V input
A1, inverting input:            0.5 mV                               
1.7 mV
A1, non-inverting:             9.3 mV                              0.3  
mV
A1, output:                       -0.67 V                              
-0.73 V
Q1, base:                         0.52 V                                
0.71 V
Q5, base:                         0.5  
V                                 -0.5 V
Q2, base:                         6.3 mV                               
-23.1 mV
Q2, emitter:                      -0.68 V                              
-0.73 V

Thanks in advance for any help you guys can provide.

-Adam Troyer
>



From aankrom at bluemarble.net  Tue Apr 29 05:05:17 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 23:05:17 -0400
Subject: [sdiy] Varistors in tremolo circuits: worth it? Merits of various
	tremolo methods?
References: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>
Message-ID: <011501c8a9a5$dc7544f0$0202a8c0@positronium>

I have a nice stash of many varistors that I've collected from countless old 
power supplies & surge protectors & such.

I noticed that Magnatone used varistors in at least one of their amps - I 
think it was for the tremolo circuit. How does the sound quality compare to 
other tremolo circuits? Is it worth the hassle of figuring out what the 
specs of each of my varistors is and trying it out? I have quite a few 
SNR130K20's.

This made me wonder about a comparison of all of the methods used for 
tremolo circuits in tube amps: how do they compare? Which is better? Or is 
it more of a Beethoven vs. Bach comparison?

I notice that most amps that have tremolo are push-pull amps and the LFO 
modulates the bias on the power tubes.

Single-ended amps with tremolo do it by varying the cathode bias of the last 
gain stage before the power tube.

There is definitely room for a big difference in the way the tremolo could 
sound between these methods.

And then there is the lamp/LDR method that seems to be a lot less common in 
tube amps, although many great tremolos have been made based on LDR's. I 
think both neon and incandescent lamps have been used. I would guess that 
neon would yield a nice and choppy tremolo, but wouldn't be reliable over 
time. Same with the incandescent lamp really.

And THEN I started thinking about tube amps with tremolo AND reverb and how 
the reverb sound is modulated along with the dry signal just the same, but I 
would think that it would be better to have the tremolo bang on the reverb. 
My studies of Hammond Organ schematics have revealed their clever way of 
doing this: they just take the output from the main amp, use a light bulb to 
reduce the volume and drive the reverb tank straight from that - no reverb 
transformer. The reverb output goes to a separate amp and maybe even its own 
speaker. But it made me think you could make a groovy little(ish) 2x10 combo 
amp with a tremolo/dry sound in one speaker and another amp with the reverb 
sound, taken from the secondary output of the 1st amp's output transformer 
straight into the reverb tank (with attenuation of course). You could 
probably do it with one speaker by mixing the reverb back into the power 
tube.

Lastly, I want to make a dual clone of a Gibson GA-5T Crestline (have the 
6AQ5A's and the 6X4's...). I want to make the tremolo(s) work independent, 
in unison (just one LFO) and then panning. One thing I don't think I've seen 
a schematic for is a tube circuit that shifts the phase of an LFO signal 180 
degrees. Pretty much the same way you'd do it with solid state parts?

SpongeBob SquarePants,
Anthony 




From sounddoctorin at imt.net  Tue Apr 29 05:26:31 2008
From: sounddoctorin at imt.net (Bob Weigel)
Date: Mon, 28 Apr 2008 21:26:31 -0600
Subject: [sdiy] Varistors in tremolo circuits: worth it? Merits of various
	tremolo methods?
In-Reply-To: <011501c8a9a5$dc7544f0$0202a8c0@positronium>
References: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>
	<011501c8a9a5$dc7544f0$0202a8c0@positronium>
Message-ID: <48169567.7090805@imt.net>

It's not a tremolo.  It's vibrato.  That's what made the magnatone 
special.   It is a cool circuit for sure.  Had to troubleshoot one long 
ago. Was a pain. -Bob

anthony wrote:

> I have a nice stash of many varistors that I've collected from 
> countless old power supplies & surge protectors & such.
>
> I noticed that Magnatone used varistors in at least one of their amps 
> - I think it was for the tremolo circuit. How does the sound quality 
> compare to other tremolo circuits? Is it worth the hassle of figuring 
> out what the specs of each of my varistors is and trying it out? I 
> have quite a few SNR130K20's.
>
> This made me wonder about a comparison of all of the methods used for 
> tremolo circuits in tube amps: how do they compare? Which is better? 
> Or is it more of a Beethoven vs. Bach comparison?
>
> I notice that most amps that have tremolo are push-pull amps and the 
> LFO modulates the bias on the power tubes.
>
> Single-ended amps with tremolo do it by varying the cathode bias of 
> the last gain stage before the power tube.
>
> There is definitely room for a big difference in the way the tremolo 
> could sound between these methods.
>
> And then there is the lamp/LDR method that seems to be a lot less 
> common in tube amps, although many great tremolos have been made based 
> on LDR's. I think both neon and incandescent lamps have been used. I 
> would guess that neon would yield a nice and choppy tremolo, but 
> wouldn't be reliable over time. Same with the incandescent lamp really.
>
> And THEN I started thinking about tube amps with tremolo AND reverb 
> and how the reverb sound is modulated along with the dry signal just 
> the same, but I would think that it would be better to have the 
> tremolo bang on the reverb. My studies of Hammond Organ schematics 
> have revealed their clever way of doing this: they just take the 
> output from the main amp, use a light bulb to reduce the volume and 
> drive the reverb tank straight from that - no reverb transformer. The 
> reverb output goes to a separate amp and maybe even its own speaker. 
> But it made me think you could make a groovy little(ish) 2x10 combo 
> amp with a tremolo/dry sound in one speaker and another amp with the 
> reverb sound, taken from the secondary output of the 1st amp's output 
> transformer straight into the reverb tank (with attenuation of 
> course). You could probably do it with one speaker by mixing the 
> reverb back into the power tube.
>
> Lastly, I want to make a dual clone of a Gibson GA-5T Crestline (have 
> the 6AQ5A's and the 6X4's...). I want to make the tremolo(s) work 
> independent, in unison (just one LFO) and then panning. One thing I 
> don't think I've seen a schematic for is a tube circuit that shifts 
> the phase of an LFO signal 180 degrees. Pretty much the same way you'd 
> do it with solid state parts?
>
> SpongeBob SquarePants,
> Anthony
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>


From synth1 at airmail.net  Tue Apr 29 05:42:56 2008
From: synth1 at airmail.net (Paul Schreiber)
Date: Mon, 28 Apr 2008 22:42:56 -0500
Subject: [sdiy] Fwd: SDIY list troubles
References: <48166E04.10707@gatech.edu>
	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
Message-ID: <021601c8a9ab$1ccdcbd0$b000a8c0@curley>

I'm going to make some GWACs (General Wild-Assed Comments):

a) never believe National Semi app notes written before 2000. Most of them
were authored by co-op students, especially the 1980s ones. Linear Tech app 
notes
are wonderful as are Maxim Semis. But a lot of National's are a bit....odd.

b) Is the substrate of the array tied through a 10K to -15V? National likes 
to leave this
little tidbit off most app notes. It's the 'Q5' of the *array*, not in the 
schematic
(notice how 'Q5' is skipped in the LM3046, but there is no reference to 
connecting
the substrate to anything.). If this pin is let floating (which I'm betting 
it is) then you
can get all sorts of interesting things, especially if you use old-fashioned 
ProtoBoards
(the white things you can stick stuff in and not use solder).

c) If you see *any* circuit using a LF412 *RUN LIKE HELL*. Easily the worse 
op amp ever
made (second to the National LM833 total POS audio part...ack!). I worked 
for a major
central office telecom supplier, and we almost went bankrupt over LF412s in 
circuits doing
all sorts of interesting things like oscillating at 10Mhz as the *humidity* 
changed, Q of filters
moving depending on how much *light* the IC package was exposed to. I 
designed fancy
multi-band filter (a delay equalizer for 2400 baud modems over leased-lines) 
using NE5532s
and the factory "upgraded" to LF412s and I spent many hours sitting in 
telecom closets in elevator
shafts getting it to work, we finally had VP of Engineering literally throw 
out every LF412 in the system,
the factory was solder-sucking parts off finished goods for weeks.

It would not surprise me if this particualr circuit used a 'quirk' of the 
LF412 to "start up", or worse
the designer 'just got lucky'. This is like Buchla paralleling CA3160 op amp 
*outputs* to exploit
a 'quirk' in the output stage (plugging in any other op amp causes bad 
things to happen).

d) LF412s are *VERY VERY VERY* sensitive to power supply noise and 
decoupling.
Silly observation: is the op amp powered off true +-15V? You need to be sure 
pins 4 and 8
ahave at lrast a 0.1mf ceramic bypass, perferred with a 10uf electrolytic in 
parallel. Even if using a
TL072 here, is it bypassed?

Paul S.







From aankrom at bluemarble.net  Tue Apr 29 05:54:00 2008
From: aankrom at bluemarble.net (anthony)
Date: Mon, 28 Apr 2008 23:54:00 -0400
Subject: [sdiy] Varistors in tremolo circuits: worth it? Merits of various
	tremolo methods?
References: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>
	<011501c8a9a5$dc7544f0$0202a8c0@positronium>
	<48169567.7090805@imt.net>
Message-ID: <011a01c8a9ac$aa0f2f10$0202a8c0@positronium>

Whoa, so it's really like a frequency-modulating vibrato? There's so much 
confusion in the music world as to which is which. I always have a clear 
distinction in my mind: The whammy bar is a VIBRATO and the knob marked 
"Vibrato" on that Fender amp (someone else's, not mine for sure... only 
because I am a pauper...) is tremolo. And a Leslie speaker does both at the 
same time: with two mics you can make one or the other stand out more, along 
with stereo spread etc. etc. And of course I've always been partial to the 
Hammond scanner vibrato. I need more electromechanical sound-makers in my 
life! (Hmmm I have a lot of solenoids and a couple of child's 
xylophones...). Always wanted to make a sequencer that was based on a 
spinning rotor, lights/LDR's or even hall effect sensors.

But I digress...

So, how do varistors make true vibrato possible? (Perhaps I should pore over 
the schematic I have a little more carefully...)

St. Elsewhere,
Anthony


----- Original Message ----- 
From: "Bob Weigel" <sounddoctorin at imt.net>
To: "anthony" <aankrom at bluemarble.net>; "synthdiy" 
<synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 28, 2008 11:26 PM
Subject: Re: [sdiy] Varistors in tremolo circuits: worth it? Merits of 
various tremolo methods?


> It's not a tremolo.  It's vibrato.  That's what made the magnatone 
> special.   It is a cool circuit for sure.  Had to troubleshoot one long 
> ago. Was a pain. -Bob
>
> anthony wrote:
>
>> I have a nice stash of many varistors that I've collected from countless 
>> old power supplies & surge protectors & such.
>>
>> I noticed that Magnatone used varistors in at least one of their amps - I 
>> think it was for the tremolo circuit. How does the sound quality compare 
>> to other tremolo circuits? Is it worth the hassle of figuring out what 
>> the specs of each of my varistors is and trying it out? I have quite a 
>> few SNR130K20's.
>>
>> This made me wonder about a comparison of all of the methods used for 
>> tremolo circuits in tube amps: how do they compare? Which is better? Or 
>> is it more of a Beethoven vs. Bach comparison?
>>
>> I notice that most amps that have tremolo are push-pull amps and the LFO 
>> modulates the bias on the power tubes.
>>
>> Single-ended amps with tremolo do it by varying the cathode bias of the 
>> last gain stage before the power tube.
>>
>> There is definitely room for a big difference in the way the tremolo 
>> could sound between these methods.
>>
>> And then there is the lamp/LDR method that seems to be a lot less common 
>> in tube amps, although many great tremolos have been made based on LDR's. 
>> I think both neon and incandescent lamps have been used. I would guess 
>> that neon would yield a nice and choppy tremolo, but wouldn't be reliable 
>> over time. Same with the incandescent lamp really.
>>
>> And THEN I started thinking about tube amps with tremolo AND reverb and 
>> how the reverb sound is modulated along with the dry signal just the 
>> same, but I would think that it would be better to have the tremolo bang 
>> on the reverb. My studies of Hammond Organ schematics have revealed their 
>> clever way of doing this: they just take the output from the main amp, 
>> use a light bulb to reduce the volume and drive the reverb tank straight 
>> from that - no reverb transformer. The reverb output goes to a separate 
>> amp and maybe even its own speaker. But it made me think you could make a 
>> groovy little(ish) 2x10 combo amp with a tremolo/dry sound in one speaker 
>> and another amp with the reverb sound, taken from the secondary output of 
>> the 1st amp's output transformer straight into the reverb tank (with 
>> attenuation of course). You could probably do it with one speaker by 
>> mixing the reverb back into the power tube.
>>
>> Lastly, I want to make a dual clone of a Gibson GA-5T Crestline (have the 
>> 6AQ5A's and the 6X4's...). I want to make the tremolo(s) work 
>> independent, in unison (just one LFO) and then panning. One thing I don't 
>> think I've seen a schematic for is a tube circuit that shifts the phase 
>> of an LFO signal 180 degrees. Pretty much the same way you'd do it with 
>> solid state parts?
>>
>> SpongeBob SquarePants,
>> Anthony
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
>
> 




From lanterma at ece.gatech.edu  Tue Apr 29 06:08:21 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 00:08:21 -0400
Subject: [sdiy] AN-299 VCO troubles [was: SDIY list troubles]
In-Reply-To: <021601c8a9ab$1ccdcbd0$b000a8c0@curley>
References: <48166E04.10707@gatech.edu>
	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
	<021601c8a9ab$1ccdcbd0$b000a8c0@curley>
Message-ID: <CA8150B1-1AE5-4903-AAA5-776B6DE3E48B@ece.gatech.edu>

On Apr 28, 2008, at 11:42 PM, Paul Schreiber wrote:

> a) never believe National Semi app notes written before 2000. Most  
> of them
> were authored by co-op students, especially the 1980s ones. Linear  
> Tech app notes are wonderful as are Maxim Semis. But a lot of  
> National's are a bit....odd.

Good bit of advice.

I admit that I've somewhat been using students as guinea pigs to try  
out things I don't have time to try out. I pay attention to how much  
time they're putting in (I'm in lab almost all the time when they're  
working on their projects) and take that into account, along with the  
"risk" of a given project, when grading. I expect people working on  
"proven" designs to get further than people who are working on less- 
proven thing (say random data sheet examples) or more experimental,  
original designs.

> b) Is the substrate of the array tied through a 10K to -15V?  
> National likes to leave this little tidbit off most app notes. It's  
> the 'Q5' of the *array*, not in the schematic (notice how 'Q5' is  
> skipped in the LM3046, but there is no reference to connecting the  
> substrate to anything.). If this pin is let floating (which I'm  
> betting it is) then you can get all sorts of interesting things,  
> especially if you use old-fashioned ProtoBoards (the white things  
> you can stick stuff in and not use solder).

Ohhhhh... you know... I'm pretty sure that's currently floating. I  
will pass all this on to Adam.

That substrate pin has caused my students any number of problems in  
the past. I try to remember to tell them about it but sometimes I  
forget.

> c) If you see *any* circuit using a LF412 *RUN LIKE HELL*. Easily  
> the worse op amp ever made (second to the National LM833 total POS  
> audio part...ack!). I worked for a major central office telecom  
> supplier, and we almost went bankrupt over LF412s in circuits doing  
> all sorts of interesting things like oscillating at 10Mhz as the  
> *humidity* changed, Q of filters moving depending on how much  
> *light* the IC package was exposed to. I designed fancy multi-band  
> filter (a delay equalizer for 2400 baud modems over leased-lines)  
> using NE5532s and the factory "upgraded" to LF412s and I spent many  
> hours sitting in telecom closets in elevator shafts getting it to  
> work, we finally had VP of Engineering literally throw out every  
> LF412 in the system, the factory was solder-sucking parts off  
> finished goods for weeks.

Wow.

Adam's using TL08x/TL07x's (they're sort of my standard op amp to hand  
students unless there's particular reason to do otherwise).

> It would not surprise me if this particualr circuit used a 'quirk'  
> of the LF412 to "start up", or worse the designer 'just got lucky'.  
> This is like Buchla paralleling CA3160 op amp *outputs* to exploit a  
> 'quirk' in the output stage (plugging in any other op amp causes bad  
> things to happen).

Oh - if that's the case that's bad news... I can pick up some LF412s  
from Ack tomorrow (I doubt they have them in our stockroom) and see if  
that makes a difference.

Re: the Buchla - good grief! What circuit did he do that in?

> d) LF412s are *VERY VERY VERY* sensitive to power supply noise and  
> decoupling. Silly observation: is the op amp powered off true +-15V?  
> You need to be sure pins 4 and 8 ahave at lrast a 0.1mf ceramic  
> bypass, perferred with a 10uf electrolytic in parallel. Even if  
> using a TL072 here, is it bypassed?

Probably not... and that's my fault. I have been negligent in  
instructing my students in proper bypass hygene.

- Aaron


From lanterma at ece.gatech.edu  Tue Apr 29 06:13:16 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 00:13:16 -0400
Subject: [sdiy] Unused CA3046 for transistors: best practices
Message-ID: <25CC8367-1F46-4F30-8AB3-C7D32560737B@ece.gatech.edu>

I know the substrate pin of a CA3046 should be attached to the most  
negative voltage the transistors will see (Paul suggested doing so  
through a 10K resistor).

If that particular transistor isn't being used, what should we do with  
its other connections?

For the other transistors, what's the best thing to do with the  
transistors that aren't being used?

- Aaron


From lanterma at ece.gatech.edu  Tue Apr 29 06:19:45 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 00:19:45 -0400
Subject: [sdiy] 3 student projects working so far!
Message-ID: <D3884EA1-2ED9-422A-BAD3-4CA65C895E40@ece.gatech.edu>

Spent a long time helping people debug and tweak today.

Today we have confirmed, working on the breadboard, and musically  
tweaked, and hence going into solder:

1) Highpass Sallen-Key based on SSM2040 datasheet, using OTAs
2) Cauer filter based on SSM2040 datasheet, using OTAs
3) Diode ladder LPF based on Roland 100

The lab is alive with the sounds of filter sweeps!

11 more to go (in various stages of being close or far from going,  
some close, some far...)

When I get the final reports in I'll post them on line so other people  
can build, tweak, and enjoy.

- Aaron


From lanterma at ece.gatech.edu  Tue Apr 29 07:10:26 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 01:10:26 -0400
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz offset!
Message-ID: <D92B377D-BDA2-4A30-86FA-4A5DE3E049F4@ece.gatech.edu>

Greg and I spend a lot of time today banging our head against the  
Bergfotron VCO.

http://hem.bredband.net/bersyn/VCO/VCO%20Buchla%20core.gif

The good news is that it's triangle is now triangular. It turned out  
to be a "bad" LM394. I don't know if it came mismatched, or if we  
somehow damaged it in our various explorations, but anyway when I  
grabbed a handful of LM394s and swapped them all in, the all gave nice  
even triangles, except for that bad one. (Thanks to the many people  
who wrote in with suggestions about the lack-of-triangularness issue!)  
In our explorations, we even swapped in some crappy 5% 5k1 resistors  
at the top of the OTA, and it still looks beautifully symmetric.

The other good news is it now shows an exponential change in frequency  
with CV.

The bad news is that it seems to add a 4 kHz offset on top of that!

The lowest frequency we can get out of it is around 4 kHz.

Of course, I immediately suspected the expo converter.

1) Tweaking the CVs so that we read 0 V at the base of the left  
transistor in the expo pair, we measured the voltage drop across the  
6.8 K resistor, and found that there was about 200 muA going through  
it. We measured the voltage drop across the 150K resistor, and deduced  
there was around 100 muA going through that. Then for grins we put a  
910 ohm resistor between the emitters of the NPN diff pair of the OTA  
and the collector of the right transistor of the expo pair. We  
measured the voltage across it, and deduced the current through it to  
be around 100 muA. So the balanced case seems to work right.

The freq of the oscillator should be current/(2*Vpp*C).

Plugging in 100 mA, 4.6 Vp-p (what the scope read for the triangle),  
and 4700 pF gives 2312 Hz. But instead we got something like 6 KHz out  
(didn't write down the exact number).

2) We then tweaked the CV input down to zero. (The range adjustment  
knob puts in some negative CV for us.) We then measured the voltage  
difference between the bases, and used it to try to deduce the  
expected frequency, and came up with something like 290 Hz. But  
something like 4.3 kHz ish (don't recall for sure) came out.

3) When I crank the CV volt by volt, and subtract around 4 kHz in my  
head, I'm pretty sure I see a doubling effect as I add each volt  
(again, once I subtract 4 Khz.)

4) If I turn around the freq = current/(2*Vpp*C) formula, and write it  
as

current = freq*2*vpp*c, I can plug in 4K and see what current I would  
imagine would be needed to get that 4K, and it comes out to 170  
microamps. So it's like all these magic microamps appear out of nowhere.

5) Oh, here's the wild part: we can COMPLETELY DISCONNECT THE EXPO  
CONVERTER altogether - i.e. disconnect the emitters of the diff pair  
in the OTA from the collector of the right transistor of the expo  
converter - and it still happily oscillates in the kHz range! (We  
discovered this when putting in the 910 ohm resistor mentioned above).

Any ideas? Anyone run into this mystery offset before?

- Aaron

P.S. What pains me is I have a MOTM VCO with a similar phenomenon,  
except it has an offset of 50 KHz! Paul gave me some troubleshooting  
tips, and I plan to get back to it over the summer hopefully. Anyway,  
the MOTM is a completely different design.


From lanterma at ece.gatech.edu  Tue Apr 29 07:20:42 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 01:20:42 -0400
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz offset!
In-Reply-To: <D92B377D-BDA2-4A30-86FA-4A5DE3E049F4@ece.gatech.edu>
References: <D92B377D-BDA2-4A30-86FA-4A5DE3E049F4@ece.gatech.edu>
Message-ID: <BEC1049A-B053-4A72-815B-0D58A1C0303E@ece.gatech.edu>


On Apr 29, 2008, at 1:10 AM, Aaron Lanterman wrote:

> The good news is that it's triangle is now triangular.

Aaah! "its triangle" not "it's!"

I have fallen prey to one of my own grammatical pet peeves!

- Aaron


From uzs159 at uni-bonn.de  Tue Apr 29 14:09:08 2008
From: uzs159 at uni-bonn.de (=?ISO-8859-1?Q?Ren=E9_Schmitz?=)
Date: Tue, 29 Apr 2008 14:09:08 +0200
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz offset!
In-Reply-To: <D92B377D-BDA2-4A30-86FA-4A5DE3E049F4@ece.gatech.edu>
References: <D92B377D-BDA2-4A30-86FA-4A5DE3E049F4@ece.gatech.edu>
Message-ID: <48170FE4.9050406@uni-bonn.de>

Hi Aaron and all,

Aaron Lanterman schrieb:
  > 4) If I turn around the freq = current/(2*Vpp*C) formula, and write 
it as
> 
> current = freq*2*vpp*c, I can plug in 4K and see what current I would 
> imagine would be needed to get that 4K, and it comes out to 170 
> microamps. So it's like all these magic microamps appear out of nowhere.
> 
> 5) Oh, here's the wild part: we can COMPLETELY DISCONNECT THE EXPO 
> CONVERTER altogether - i.e. disconnect the emitters of the diff pair in 
> the OTA from the collector of the right transistor of the expo converter 
> - and it still happily oscillates in the kHz range! (We discovered this 
> when putting in the 910 ohm resistor mentioned above).

Disconnecting the expo is a good "divide and conquer" debugging 
technique, you can test both pieces individually. I often do this as 
well when there is some problem.

> Any ideas? Anyone run into this mystery offset before?

It will be some leakage current again, but its difficult to say where 
exactly this might occur. I'd try swapping the transistors in the "OTA" 
first, and maybe the integrator opamps, since you already encountered 
some faulty components, it might be that there was more damage done to 
other components.

Cheers,
  Ren?






From music.maker at gte.net  Tue Apr 29 15:09:11 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Tue, 29 Apr 2008 06:09:11 -0700
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz offset!
Message-ID: <200804291309.m3TD9B8u018102@linux7.lan>

Aaron Lanterman <lanterma at ece.gatech.edu> wrote:

>5) Oh, here's the wild part: we can COMPLETELY DISCONNECT THE EXPO  
>CONVERTER altogether - i.e. disconnect the emitters of the diff pair  
>in the OTA from the collector of the right transistor of the expo  
>converter - and it still happily oscillates in the kHz range! (We  
>discovered this when putting in the 910 ohm resistor mentioned above).
>
>Any ideas? Anyone run into this mystery offset before?

That's interesting and suggests that the oscillator is being fed current, somehow,
without the expo converter - I believe that if you find the source of this current,
you'll also have the source of the "offset".  A misplaced resistor?

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From patchell at cox.net  Tue Apr 29 15:10:17 2008
From: patchell at cox.net (Jim Patchell)
Date: Tue, 29 Apr 2008 06:10:17 -0700
Subject: [sdiy] Unused CA3046 for transistors: best practices
In-Reply-To: <25CC8367-1F46-4F30-8AB3-C7D32560737B@ece.gatech.edu>
References: <25CC8367-1F46-4F30-8AB3-C7D32560737B@ece.gatech.edu>
Message-ID: <48171E39.3050602@cox.net>

Just leave them hanging...no probs...

Aaron Lanterman wrote:
> I know the substrate pin of a CA3046 should be attached to the most 
> negative voltage the transistors will see (Paul suggested doing so 
> through a 10K resistor).
> 
> If that particular transistor isn't being used, what should we do with 
> its other connections?
> 
> For the other transistors, what's the best thing to do with the 
> transistors that aren't being used?
> 
> - Aaron
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> 

-- 
----------------------------------------------
Visit http://www.noniandjim.com
SDIY: http://www.noniandjim.com/Jim/index.html
----------------------------------------------



From dave at westphila.net  Tue Apr 29 15:10:21 2008
From: dave at westphila.net (David Moylan)
Date: Tue, 29 Apr 2008 09:10:21 -0400
Subject: [sdiy] Varistors in tremolo circuits: worth it? Merits of various
	tremolo methods?
In-Reply-To: <48169567.7090805@imt.net>
References: <4816311f.0ac0100a.1d0c.ffffdb42@mx.google.com>	<011501c8a9a5$dc7544f0$0202a8c0@positronium>
	<48169567.7090805@imt.net>
Message-ID: <48171E3D.8020707@westphila.net>

Don't forget the 'harmonic tremelo' found in many brown Fender amps.  It 
splits the signal into two frequency bands and modulates them out of 
phase.  Gives a nice subtle phasing effect and sounds much more 
interesting to my ears than a standard trem.  The modulation is 
accomplished by varying the bias on the grids, but since the two control 
signals are out of phase and end up mixed the CVs cancel (in theory; 
tubes aren't usually very well balanced).



Bob Weigel wrote:
> It's not a tremolo.  It's vibrato.  That's what made the magnatone 
> special.   It is a cool circuit for sure.  Had to troubleshoot one long 
> ago. Was a pain. -Bob
> 
> anthony wrote:
> 
>> I have a nice stash of many varistors that I've collected from 
>> countless old power supplies & surge protectors & such.
>>
>> I noticed that Magnatone used varistors in at least one of their amps 
>> - I think it was for the tremolo circuit. How does the sound quality 
>> compare to other tremolo circuits? Is it worth the hassle of figuring 
>> out what the specs of each of my varistors is and trying it out? I 
>> have quite a few SNR130K20's.
>>
>> This made me wonder about a comparison of all of the methods used for 
>> tremolo circuits in tube amps: how do they compare? Which is better? 
>> Or is it more of a Beethoven vs. Bach comparison?
>>
>> I notice that most amps that have tremolo are push-pull amps and the 
>> LFO modulates the bias on the power tubes.
>>
>> Single-ended amps with tremolo do it by varying the cathode bias of 
>> the last gain stage before the power tube.
>>
>> There is definitely room for a big difference in the way the tremolo 
>> could sound between these methods.
>>
>> And then there is the lamp/LDR method that seems to be a lot less 
>> common in tube amps, although many great tremolos have been made based 
>> on LDR's. I think both neon and incandescent lamps have been used. I 
>> would guess that neon would yield a nice and choppy tremolo, but 
>> wouldn't be reliable over time. Same with the incandescent lamp really.
>>
>> And THEN I started thinking about tube amps with tremolo AND reverb 
>> and how the reverb sound is modulated along with the dry signal just 
>> the same, but I would think that it would be better to have the 
>> tremolo bang on the reverb. My studies of Hammond Organ schematics 
>> have revealed their clever way of doing this: they just take the 
>> output from the main amp, use a light bulb to reduce the volume and 
>> drive the reverb tank straight from that - no reverb transformer. The 
>> reverb output goes to a separate amp and maybe even its own speaker. 
>> But it made me think you could make a groovy little(ish) 2x10 combo 
>> amp with a tremolo/dry sound in one speaker and another amp with the 
>> reverb sound, taken from the secondary output of the 1st amp's output 
>> transformer straight into the reverb tank (with attenuation of 
>> course). You could probably do it with one speaker by mixing the 
>> reverb back into the power tube.
>>
>> Lastly, I want to make a dual clone of a Gibson GA-5T Crestline (have 
>> the 6AQ5A's and the 6X4's...). I want to make the tremolo(s) work 
>> independent, in unison (just one LFO) and then panning. One thing I 
>> don't think I've seen a schematic for is a tube circuit that shifts 
>> the phase of an LFO signal 180 degrees. Pretty much the same way you'd 
>> do it with solid state parts?
>>
>> SpongeBob SquarePants,
>> Anthony
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 



From ijfritz at comcast.net  Tue Apr 29 15:38:03 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Tue, 29 Apr 2008 07:38:03 -0600
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz
  offset!
In-Reply-To: <200804291309.m3TD9B8u018102@linux7.lan>
References: <200804291309.m3TD9B8u018102@linux7.lan>
Message-ID: <6.2.1.2.2.20080429073258.020cc8f8@mail.comcast.net>

At 07:09 AM 4/29/2008, Scott Gravenhorst wrote:
>Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
>
> >5) Oh, here's the wild part: we can COMPLETELY DISCONNECT THE EXPO
> >CONVERTER altogether - i.e. disconnect the emitters of the diff pair
> >in the OTA from the collector of the right transistor of the expo
> >converter - and it still happily oscillates in the kHz range!


What does it look like on the scope?  Do the two waveforms look like a 
proper tri/square?  Or is it self-oscillating from feedback.  (You've read 
and followed the precautions in the application hints section of the 311 
data sheet?)

Ian 



From flightofharmony at comcast.net  Tue Apr 29 16:09:32 2008
From: flightofharmony at comcast.net (flight)
Date: Tue, 29 Apr 2008 07:09:32 -0700
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
References: <48166E04.10707@gatech.edu>
	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
Message-ID: <000001c8aa02$a70135b0$f503a110$@net>

Last year I spent a few weeks playing around with this circuit. I used a
TL074, which worked fine. The VCO works nice except for its horrible drift -
I probably should have insulated the CA3046 from stray air currents. I
abandoned the project finally, as I just couldn't get it to stabilize. I ran
it for up to 5 hours and it just wouldn't sit still! It also has a lengthy
warm-up period while the array heats up (5+ mins). Here's the schematic I
drew from the App Note: http://www.flightofharmony.com/stash/AN299 VCO.pdf .

~flight  

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Aaron Lanterman
Sent: Monday, April 28, 2008 7:20 PM
To: SDIY
Subject: [sdiy] Fwd: SDIY list troubles

Howdy - My student Adam is trying a different oscillator now and  
having trouble both with the oscillator and posting to the list, so  
I'm forwarding it for him...

- Aaron

P.S. We're using a TL08x/TL07x series op amp.

------------------

The message:

Hey everyone.  I'm building the exponential V-F oscillator in figure 1  
of this app note:
http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/AN-299.pdf 
, and once again I'm getting no oscillations at the output, even after  
putting it through a TL072 buffer and inverting amp to boost it.  We  
took DC voltage readings at a bunch of points in the circuit at 0V  
input  and 15V of input to see if they changed right.  One thing I  
noticed is that the Vbe of Q1 is  changing, so the current from Q1  
_should_ be varying exponentially like it's supposed to.  I put an  
ammeter between the emitter of Q1 and the inverting input of A1 and  
saw no current, but  Aaron told me that can be pretty unreliable.

Anyway, listed below are the DC voltages we measured while  
experimenting with the circuit. Can anyone see any reasons why this  
isn't working?

Node                               Vdc at 0V input               Vdc  
at 15V input
A1, inverting input:            0.5 mV                               
1.7 mV
A1, non-inverting:             9.3 mV                              0.3  
mV
A1, output:                       -0.67 V                              
-0.73 V
Q1, base:                         0.52 V                                
0.71 V
Q5, base:                         0.5  
V                                 -0.5 V
Q2, base:                         6.3 mV                               
-23.1 mV
Q2, emitter:                      -0.68 V                              
-0.73 V

Thanks in advance for any help you guys can provide.

-Adam Troyer
>

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From samppa.tolvanen at gmail.com  Tue Apr 29 17:05:07 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 29 Apr 2008 18:05:07 +0300
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <000001c8aa02$a70135b0$f503a110$@net>
References: <48166E04.10707@gatech.edu>
	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
	<000001c8aa02$a70135b0$f503a110$@net>
Message-ID: <fa1b0bd80804290805q2d151f86tac0a32983ebf0888@mail.gmail.com>

On 4/29/08, flight <flightofharmony at comcast.net> wrote:
> Last year I spent a few weeks playing around with this circuit. I used a
>  TL074, which worked fine. The VCO works nice except for its horrible drift -
>  I probably should have insulated the CA3046 from stray air currents. I
>  abandoned the project finally, as I just couldn't get it to stabilize. I ran
>  it for up to 5 hours and it just wouldn't sit still! It also has a lengthy
>  warm-up period while the array heats up (5+ mins). Here's the schematic I
>  drew from the App Note: http://www.flightofharmony.com/stash/AN299 VCO.pdf .
>

Ahha.

Are we back to Ian Fritz Electronotes clone (?) circuit
(http://home.comcast.net/~ijfritz/sy_cir2.htm with some mods) for some
stability in expo/tempco driven sawtooth cores? You don't specify any
figures for the drift.

Samppa


From jonathan_science at hotmail.com  Tue Apr 29 17:41:11 2008
From: jonathan_science at hotmail.com (J P)
Date: Tue, 29 Apr 2008 11:41:11 -0400
Subject: [sdiy] MS-20 LFO in Audio?
Message-ID: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>


Hey Guys (and Gals?)

I'm trying to build a really neat-0 ring modulator modulation source.  I remember Tom Gamble over at EFM used to have a schematic for an MS-20 LFO...  I recall it going into audio range (which, unless this is a really unique and interesting oscillator, I assume would just be a matter of smallering down the timing cap)...  Anyhow.  Can someone point me to an MS-20 LFO schematic?

Also, are there any simplifications or refinements people like to perform on these LFOs?

Cheers,

Jonathan P

_________________________________________________________________
Spell a grand slam in this game where word skill meets World Series. Get in the game.
http://club.live.com/word_slugger.aspx?icid=word_slugger_wlhm_admod_april08


From lanterma at ece.gatech.edu  Tue Apr 29 18:12:54 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 12:12:54 -0400
Subject: [sdiy] Berfotron/Buchla now triangular, but with 4KHz offset!
In-Reply-To: <6.2.1.2.2.20080429073258.020cc8f8@mail.comcast.net>
References: <200804291309.m3TD9B8u018102@linux7.lan>
	<6.2.1.2.2.20080429073258.020cc8f8@mail.comcast.net>
Message-ID: <C1DA21E5-AAEE-4FA9-B693-21745BC6BA3D@ece.gatech.edu>


On Apr 29, 2008, at 9:38 AM, Ian Fritz wrote:
>
> What does it look like on the scope?  Do the two waveforms look like  
> a proper tri/square?  Or is it self-oscillating from feedback.   
> (You've read and followed the precautions in the application hints  
> section of the 311 data sheet?)

It looks to me like a proper triangle (and square from the square wave  
output), not a sine wave.

Ah, wasn't familiar with the application hint precautions on the  
311... we'll check those out...

- Aaron


From samppa.tolvanen at gmail.com  Tue Apr 29 18:37:43 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 29 Apr 2008 19:37:43 +0300
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
Message-ID: <fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>

On 4/29/08, J P <jonathan_science at hotmail.com> wrote:
>
> ...  Anyhow.  Can someone point me to an MS-20 LFO schematic?
>

Yes,

Look at the MS-20 schematics.

Samppa


From lanterma at ece.gatech.edu  Tue Apr 29 18:42:29 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Tue, 29 Apr 2008 12:42:29 -0400
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
	<fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
Message-ID: <88B6FA79-5690-4DA3-AB30-9246679C0B53@ece.gatech.edu>


On Apr 29, 2008, at 12:37 PM, Samppa Tolvanen wrote:

> On 4/29/08, J P <jonathan_science at hotmail.com> wrote:
>>
>> ...  Anyhow.  Can someone point me to an MS-20 LFO schematic?
>>
>
> Yes,
>
> Look at the MS-20 schematics.

I think JP was looking for a link:

http://www.korganalogue.net/korgms/service/ms20/m20s.html

Particularly

http://www.korganalogue.net/korgms/images/service/ms20/circ1.gif

- Aaron


From samppa.tolvanen at gmail.com  Tue Apr 29 18:44:17 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 29 Apr 2008 19:44:17 +0300
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
	<fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
Message-ID: <fa1b0bd80804290944y7339d57dy199bcb550934ad7f@mail.gmail.com>

On 4/29/08, Samppa Tolvanen <samppa.tolvanen at gmail.com> wrote:
>
> Yes,
>
>  Look at the MS-20 schematics.
>

Oh, I forgot - crop the schematics of the LFO section too, so You'll
be back to ask how opamps are powered ;=)

Samppa


From dlmanley at sonic.net  Tue Apr 29 19:00:29 2008
From: dlmanley at sonic.net (Dave Manley)
Date: Tue, 29 Apr 2008 10:00:29 -0700
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
Message-ID: <4817542D.5090504@sonic.net>

Service info is here:

http://www.korganalogue.net/korgms/service/ms20/m20s.html

For the LFO specifically look for the block labeled 'Modulation 
Generator' in this schematic:

http://www.korganalogue.net/korgms/images/service/ms20/circ1.gif

-Dave

J P wrote:
> Hey Guys (and Gals?)
> 
> Can someone point me to an MS-20 LFO schematic?
>
> Jonathan P




From tom at electricdruid.net  Tue Apr 29 19:01:09 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Tue, 29 Apr 2008 18:01:09 +0100
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
	<fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
Message-ID: <C7902B81-167C-46BE-ADB2-D21E49F22C2B@electricdruid.net>


On 29 Apr 2008, at 17:37, Samppa Tolvanen wrote:

> On 4/29/08, J P <jonathan_science at hotmail.com> wrote:
>>
>> ...  Anyhow.  Can someone point me to an MS-20 LFO schematic?
>>
>
> Yes,
>
> Look at the MS-20 schematics.
>
> Samppa

...which you'll find at:

http://www.hylander.us/images/schematics/korg/korg_ms20_service.pdf

T.




From tom at electricdruid.net  Tue Apr 29 19:04:02 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Tue, 29 Apr 2008 18:04:02 +0100
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <000001c8aa02$a70135b0$f503a110$@net>
References: <48166E04.10707@gatech.edu>
	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
	<000001c8aa02$a70135b0$f503a110$@net>
Message-ID: <2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>


On 29 Apr 2008, at 15:09, flight wrote:

> Last year I spent a few weeks playing around with this circuit. I  
> used a
> TL074, which worked fine. The VCO works nice except for its  
> horrible drift -
> I probably should have insulated the CA3046 from stray air currents. I
> abandoned the project finally, as I just couldn't get it to  
> stabilize. I ran
> it for up to 5 hours and it just wouldn't sit still! It also has a  
> lengthy
> warm-up period while the array heats up (5+ mins). Here's the  
> schematic I
> drew from the App Note: http://www.flightofharmony.com/stash/AN299  
> VCO.pdf .

I thought the whole point of this circuit was its clever temperature  
compensation. After all, that's a lot of transistor array to use for  
pure decoration. If it doesn't actually work, we might as well all go  
back to using tempcos.
Has anyone else had any experience with it to share?

Thanks,
Tom




From samppa.tolvanen at gmail.com  Tue Apr 29 19:08:28 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Tue, 29 Apr 2008 20:08:28 +0300
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <88B6FA79-5690-4DA3-AB30-9246679C0B53@ece.gatech.edu>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
	<fa1b0bd80804290937u597db355q3453bfc4d03bd1ce@mail.gmail.com>
	<88B6FA79-5690-4DA3-AB30-9246679C0B53@ece.gatech.edu>
Message-ID: <fa1b0bd80804291008g16972d1bq3208054332ece05f@mail.gmail.com>

On 4/29/08, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
>
>  On Apr 29, 2008, at 12:37 PM, Samppa Tolvanen wrote:
>
>
> > On 4/29/08, J P <jonathan_science at hotmail.com> wrote:
> >
> > >
> > > ...  Anyhow.  Can someone point me to an MS-20 LFO schematic?
> > >
> > >
> >
> > Yes,
> >
> > Look at the MS-20 schematics.
> >
>
>  I think JP was looking for a link:
>
>  http://www.korganalogue.net/korgms/service/ms20/m20s.html
>
>  Particularly
>
> http://www.korganalogue.net/korgms/images/service/ms20/circ1.gif
>
>  - Aaron
>

Ah,

Yes - but we can all Google, Can't we? I mean, most of the meaningful
questions asked *HERE* -for such newbie as I am- are from You or Your
students.

Samppa


From dlmanley at sonic.net  Tue Apr 29 19:38:31 2008
From: dlmanley at sonic.net (Dave Manley)
Date: Tue, 29 Apr 2008 10:38:31 -0700
Subject: [sdiy] AN299 VCO
In-Reply-To: <2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
References: <48166E04.10707@gatech.edu>	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>	<000001c8aa02$a70135b0$f503a110$@net>
	<2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
Message-ID: <48175D17.8090003@sonic.net>

Tom Wiltshire wrote:
> 
> 
> I thought the whole point of this circuit was its clever temperature 
> compensation. After all, that's a lot of transistor array to use for 
> pure decoration. If it doesn't actually work, we might as well all go 
> back to using tempcos.
> Has anyone else had any experience with it to share?

I don't have reference materials at hand, but isn't a very similar 
circuit used in one of the later Moog VCOs?  I can dig it out tonight if 
there's interest.

-Dave




From aankrom at bluemarble.net  Tue Apr 29 20:10:27 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 29 Apr 2008 14:10:27 -0400
Subject: [sdiy] Dead precision electronic balance yields gems,
	parts to barter
References: <48166E04.10707@gatech.edu><5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>
	<000001c8aa02$a70135b0$f503a110$@net>
Message-ID: <015401c8aa24$4f99e750$0202a8c0@positronium>

Bongiorno tutti!

My mother's boyfriend is a chemistry professor emeritus at Indiana 
University. He's pretty good at being my hook-up for old electronics gear to 
use or use for parts (I use the Beckman 60MHz scope he got me for instance, 
but took the Powerstat out of a Fisher-Johns melting point apparatus...).

The other day he gave me a precision electronic balance and I knew right 
away it would yield up some nice parts and I was not disappointed: many 
yellow, axial polypropylene caps (too bad only up to 160VDC), lots of 1% and 
some 0.1% resistors, an LM399 (a precision voltage reference with its own 
little oven). I guess the op amps disappointed a little, but they were still 
pretty good: MC1458P1's, OP07's, an LF353 and an LM311. Some good 74HCXX 
parts, a 74LS393 and some other TTL parts that I like. One of the coolest 
parts probably was an SW201, which is a quad analog switch but with JFET's. 
The 10-segment VFD alpha-numeric display with UCN4810AN controller - very 
cool as well. Of course always glad to get an LM7915 and less so an LM7815 
(I have a number of JRC LM7815A's - I need the negatives more...).

Oh and there was a cool little servo motor like you find in remote 
controlled cars. I still haven't gone through all of the electromechanical 
doo-dads, but they're pretty crusty and probably won't yield up too much...

Hmm... I suppose there aren't a lot of barter possibilities here afterall. 
Maybe the PolyP caps or someone needs an OP07?


Murder She Wrote,
Anthony 




From aym-htnys at teaser.fr  Tue Apr 29 20:23:32 2008
From: aym-htnys at teaser.fr (Andre Majorel)
Date: Tue, 29 Apr 2008 20:23:32 +0200
Subject: [sdiy] MS-20 LFO in Audio?
In-Reply-To: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
References: <BAY111-W13655E8799060D414EE189FDD90@phx.gbl>
Message-ID: <20080429182331.GB3036@aym.net2.nerim.net>

On 2008-04-29 11:41 -0400, J P wrote:

> I'm trying to build a really neat-0 ring modulator modulation
> source.  I remember Tom Gamble over at EFM used to have a
> schematic for an MS-20 LFO...  I recall it going into audio
> range (which, unless this is a really unique and interesting
> oscillator, I assume would just be a matter of smallering down
> the timing cap)...  Anyhow.  Can someone point me to an MS-20
> LFO schematic?
> 
> Also, are there any simplifications or refinements people like
> to perform on these LFOs?

The Oakley Little-LFO is based on the MS-20 LFO. Improvements
include current components (DG403, TL072) and sync input. You may
have to buy the PCB to get the schematics but it's just 9 GBP.

  http://www.oakleysound.com/lfo.htm

-- 
Andr? Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.


From aankrom at bluemarble.net  Tue Apr 29 20:24:41 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 29 Apr 2008 14:24:41 -0400
Subject: [sdiy] Anyone hack a Nintendo Virtual Boy display mechanism?
References: <48166E04.10707@gatech.edu><5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu><000001c8aa02$a70135b0$f503a110$@net>
	<2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
Message-ID: <015b01c8aa26$4c513a10$0202a8c0@positronium>

Hello,

I'm mailing this beifre I google the idea, because I value the input from 
this group and whatever hits I get might distract me from sounding the idea 
off of you guys (& gals).

I had an old Virtual Boy that I decided to take apart. I didn't have the 
custom Nistendo driver head, so I just cut away at the ABS plastic until I 
got it all away. As far as other parts go it was a bust (well the audio amp 
was kind of cool), but the really cool part was the 3D display mechanism 
which comprised of two mirrors attached to 2 galvanometers which reflect 
light from a linear LED array which scans the images in piecemeal fashion as 
the mirrors swing back and forth.

I am not interested in recreating a 3D video display for general use outside 
of it just being a gameboy (which would be cool) but I wanted to use the 
galvanometers & mirrors to respond to audio to make a light show from 
whatever audio is running through it. I could start from scratch but I 
wonder if anyone has divined the workings of the controller chips, many of 
which look totally custom.

I know Nintendo is very close about its technology so probably nobody's got 
very far, but then again I could be wrong.

I wonder if I could use the galvanometers in conjuction with a spinning 
mirror I got from a big HP laser printer and a laser pointer laser for the 
visible laser (wish they had those in blue...)


The Waltons,
Anthony 




From music.maker at gte.net  Tue Apr 29 20:34:06 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Tue, 29 Apr 2008 11:34:06 -0700
Subject: [sdiy] MS-20 LFO in Audio?
Message-ID: <200804291834.m3TIY6cR030800@linux7.lan>

Andre Majorel <aym-htnys at teaser.fr> wrote:
>On 2008-04-29 11:41 -0400, J P wrote:
>
>> I'm trying to build a really neat-0 ring modulator modulation
>> source.  I remember Tom Gamble over at EFM used to have a
>> schematic for an MS-20 LFO...  I recall it going into audio
>> range (which, unless this is a really unique and interesting
>> oscillator, I assume would just be a matter of smallering down
>> the timing cap)...  Anyhow.  Can someone point me to an MS-20
>> LFO schematic?
>> 
>> Also, are there any simplifications or refinements people like
>> to perform on these LFOs?
>
>The Oakley Little-LFO is based on the MS-20 LFO. Improvements
>include current components (DG403, TL072) and sync input. You may
>have to buy the PCB to get the schematics but it's just 9 GBP.
>
>  http://www.oakleysound.com/lfo.htm
>

I know that I'm a heretic, but when I looked at it, I thought that it might be
done in CMOS with 4069UB and 4007UB parts...  (c:

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From pfperry at melbpc.org.au  Wed Apr 30 02:16:10 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 30 Apr 2008 10:16:10 +1000
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <000001c8aa02$a70135b0$f503a110$@net>
Message-ID: <007c01c8aa57$654eaa30$8501a8c0@ice9>

Anyone using the CA3046 in feedback stabilized heater mode, note that the
transistors in the chip have to be the same ones used in the application
note.
Although the transistors are identical electrically, because of the
different physical placement in the chip, for the heater & sensor
transistors to operate properly, I think they have to be as shown in the
note.

I haven't tried this circuit myself, but I seem to remember seeing something
about this.

paul perry Melbourne Australia



From aankrom at bluemarble.net  Wed Apr 30 03:51:34 2008
From: aankrom at bluemarble.net (anthony)
Date: Tue, 29 Apr 2008 21:51:34 -0400
Subject: [sdiy] Tube microphonics: 12SQ7GT & 12AV6, 6SN7GT & 6CG7/6FQ7, etc.
References: <007c01c8aa57$654eaa30$8501a8c0@ice9>
Message-ID: <018b01c8aa64$ba534510$0202a8c0@positronium>

I have been thinking about tube microphonics lately and was wondering what 
aspects of the physical parts of the tube, like length of getter supports, 
getter position & shape, wire thickness, placement of mica supports and so 
on.

I have read that many people have found the 12AV6 & 6AV6 to be microphonic 
and a few others have complained about 12SQ7GT's being microphonic - which I 
found hard to believe at first because of the superb performance of the 
single triode preamp based on a National Union 12SQ7GT and a Tung-Sol 
50L6GT. The plate of the NU triode had a seam/fin on just one side, which I 
would think would lend itself to being non-microphonic. The 6AV6 I would 
guess is often microphonic because of the diode plates which look like a 
tuning fork. Then I got a "grab-bag" of various 12SQ7GT's on eBay. It was a 
real gamble, but all but one of the 5 were golden; the one I set aside (a 
Philco branded one) I did only because the gain was markedly less than the 
others. I also discarded the original tube I used because the others 
outshone it, none displaying the dysphonic scratchy distortion that I was 
afraid was due to a design limitation to using a plate resistor half the 
size that is usually used when the tube is a preamp tube in a common radio. 
I wanted rockin' gain, dammit! And this NU tube, which probably was a good 
one when it was new, was just shagged out. The weird thing was that one of 
the 12SQ7GT's (a Westinghouse branded one) looked just like a 12AV6, but 
stuck in an octal envelope. My guess is that it was of more recent 
manufacture for the purpose of replacing old tubes and was probably never 
used as an OEM part and using the 12AV6 innards was economical because 
they're supposed to be electrically identical to the 12SQ7 even though they 
don't look anything alike - except for this one Westinghouse tube. I 
auditioned it, expecting it to be a microphonic turd, but was surprised to 
find it one of the best tubes. The others ranged from definitely used to 
NOS-OOBFLT (NOS out of the box for a long time). So I examined to 
12AV6-looking Westinghouse 12SQ7GT and noticed that it looked like they took 
pains to make it a decent tube.

So that made me wonder what to look for in a tube. When buying tubes on eBay 
that I can't inspect up close, I usually just go for brands I know will be 
good like RCA, Tung-Sol, Mullard, etc... But some tubes are made by these, 
but branded for others. Like the Silvertone branded 12SQ7GT that looked a 
lot like the old NU, but there was another NU tube that looked different: it 
had two fins instead of just one on the triode plate. And I don't know if 
National Union made their own 12SQ7GT's or not...

This brings me to the 6CG7/6FQ7's that I have that I want to use in an amp 
design that originally used a 6SN7GT. The datasheet for the 6CG7 says it's 
electrically identical to the 6SN7, but they look very different. Of the 4 
6CG7/6FQ7's that I have the one that looks most promising is an RCA with a 
side-getter. And the relatively worst-looking one is another RCA of more 
recent vintage with a top-getter with a long support wire.

Is there anything to plate geometries tha contributes to a tube's 
microphonics?

AA 




From pfperry at melbpc.org.au  Wed Apr 30 04:26:47 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 30 Apr 2008 12:26:47 +1000
Subject: [sdiy] Tube microphonics: 12SQ7GT & 12AV6, 6SN7GT & 6CG7/6FQ7,
	etc.
In-Reply-To: <018b01c8aa64$ba534510$0202a8c0@positronium>
Message-ID: <002501c8aa69$a415f6d0$8501a8c0@ice9>

I doubt that mere visual inspection would be a good guide to microphonics.
But there is another aspect - providing an anti-microphonic support for the
tube. If no vibration reaches the tube, it hardly matters if it is
microphonic.

In a DIY situation, this might be feasible.

paul perry Melbourne Australia



From tshire at charter.net  Wed Apr 30 05:42:56 2008
From: tshire at charter.net (Travis Shire)
Date: Tue, 29 Apr 2008 23:42:56 -0400
Subject: [sdiy] Tube microphonics: 12SQ7GT & 12AV6, 6SN7GT & 6CG7/6FQ7,
	etc.
References: <007c01c8aa57$654eaa30$8501a8c0@ice9>
	<018b01c8aa64$ba534510$0202a8c0@positronium>
Message-ID: <000b01c8aa74$479b2fa0$6401a8c0@cyberup0n1qn6z>



> I have been thinking about tube microphonics lately and was wondering what
> aspects of the physical parts of the tube, like length of getter supports,
> getter position & shape, wire thickness, placement of mica supports and so
> on.
>
It depends on the tube's intended use. Some circuits aren't affected by
microphony. Not all tubes are great for audio. Plus you have to remember
that most of the oddball types have been shuffled around for 30-50 years so
the internal structure may be compromised.

A 6CG7 can be a decent low power output amp if you think outside the box a
little. Ampeg used them as capacitive coupled reverb coil drivers.

Other than that, post in usenet group rec.audio.tubes.....thats the place
where all the "toobs" hang out. You'll get far more info there and it'll be
on topic.



From lanterma at ece.gatech.edu  Wed Apr 30 07:08:32 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 30 Apr 2008 01:08:32 -0400
Subject: [sdiy] 1-pole LPF using a differential integrator?
In-Reply-To: <10ED176D-2432-4B49-9C4E-927230194993@ece.gatech.edu>
References: <10ED176D-2432-4B49-9C4E-927230194993@ece.gatech.edu>
Message-ID: <0701917A-720D-4CEC-84E5-49C3237FA441@ece.gatech.edu>

One project idea that I tossed out to my students, which one student  
is trying to get work, is to use the idea of an NPN differential amp  
driving a "differential integrator" to build a 1-pole LPF, which you  
could then do four times to get a usual 4-pole LPF.

I got the idea from the EML-101 filter schematic, as expertly redrawn  
by Marjan Urekar:

http://members.tripod.com/urekarm/synth/eml101vcf.pdf

The EML-101 is a state variable filter, and said diff amp/diff  
integrator configurations form the variable gain integrators.

My thought was that we could take the output of such an integrator,  
and feed it into the opposite input terminal of the diff pair, and  
that feedback should form a 1-pole LPF, as follows:

The NPN pair driving the differential integrator forms a variable gain  
integrator with transfer function A/RCs, where A is the voltage gain  
of the diff pair and R and C are the resistor values used in the  
integrator. Let's denote wo = A/RC. Now imagine we take the output of  
this integrator and feed it back into the input with a minus sign. You  
get something like this:

Y(s) = (wo/s) [X(s) - Y(s)]

Y(s)[1 + wo/s] = (wo/s) X(s)

Y(s)/X(s) = (wo/s) / (1+wo/s) = wo/(s+wo)

Which is the transfer function of a single-pole LPF with cutoff wo  
with unity gain at DC. (This is the same idea as a usual OTA-C filter  
1-pole LPF).

Three questions:

1) I sent my student, Justin, this sketch to get him started: http://users.ece.gatech.edu/~lanterma/eml_inspired_vcf_sketch.jpg 
, where I just blindly ganked the resistor and cap values from the EML  
circuit.

Anyway, I just realized I drew that wrong - the EML integrating stage  
is _inverting_, so we should actually either:

A) Swap the inputs on the differential integrator, to make a  
noninverting stage, or

B) Take the feedback to the left NPN instead of the right NPN

Does (A) or (B) sound like the safer option?

2) Given the way the "differential integrator" is going to load the  
differential amp, should I even be thinking of this as a differential  
amp followed by a differential integrator? Or are they interacting so  
much such thinking breaks down?

3) Does this whole crazy idea of mine sound like a decent idea at all  
or is it doomed to insanity?

- Aaron

P.S. This got me wondering if there's an "integrating version" of the  
standard 3-op-amp instrumentation amplifier? A differential integrator  
with high input impedance, but something more elegant than just  
slapping noninverting op amp buffers at the inputs to the above  
differential integrator?

http://en.wikipedia.org/wiki/Image:Opampinstrumentation.svg




From somnium7 at gmail.com  Wed Apr 30 07:16:25 2008
From: somnium7 at gmail.com (mike ruberto)
Date: Wed, 30 Apr 2008 01:16:25 -0400
Subject: [sdiy] Re: Anyone tried TLE2141?
In-Reply-To: <916920440802082058r37d0b5a0v8dc318af9f8a5dcd@mail.gmail.com>
References: <916920440802062312r71627c37teacd7c3eebe2f2eb@mail.gmail.com>
	<916920440802082058r37d0b5a0v8dc318af9f8a5dcd@mail.gmail.com>
Message-ID: <916920440804292216s2fd30149qd0d60bca62f79063@mail.gmail.com>

Sorry this is so late coming. Here's my impression of this device
after making comparisons.

Overall this is a damn good audio opamp for cheap. In my mixing
console overhaul I am using the following devices.
OP275
LME49860
TLE2141

My tests were done with 3 channels, each having one type of the opmps
listed above.

I honestly cannot hear the difference between the TLE2141 and the much
more expensive LME49860. The OP275 has a sound much different from the
other two. Not a bad sound - more punchy than the rest.

I am really impressed with this TLE2141 though. To look at it's specs
it doesn't seem like a very good choice and certainly not worth
comparing to the LME49860 but in use it sounds great.

Mike

On Sat, Feb 9, 2008 at 12:58 AM, mike ruberto <somnium7 at gmail.com> wrote:
> Well I decided to order these. Mostly because I am replacing scads of
>  4558DX and the power consumption was the same. I'll you know how I
>  like them.
>
>  Mike
>
>
>
>
>  ---------- Forwarded message ----------
>  From: mike ruberto <somnium7 at gmail.com>
>  Date: Feb 7, 2008 2:12 AM
>  Subject: Anyone tried TLE2141?
>  To: Synth DIY <synth-diy at dropmix.xs4all.nl>
>
>
>  I've been hunting around for some 44V opamps and I have it down to a
>  short list. I'm not familiar with the TLE2141 though.
>  Has anybody tried them in an audio application?
>
>
>  M. A. Ruberto
>


From lanterma at ece.gatech.edu  Wed Apr 30 07:25:04 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 30 Apr 2008 01:25:04 -0400
Subject: [sdiy] Re: Anyone tried TLE2141?
In-Reply-To: <916920440804292216s2fd30149qd0d60bca62f79063@mail.gmail.com>
References: <916920440802062312r71627c37teacd7c3eebe2f2eb@mail.gmail.com>
	<916920440802082058r37d0b5a0v8dc318af9f8a5dcd@mail.gmail.com>
	<916920440804292216s2fd30149qd0d60bca62f79063@mail.gmail.com>
Message-ID: <BC521247-2678-4B86-A8EC-422FF292E66A@ece.gatech.edu>


On Apr 30, 2008, at 1:16 AM, mike ruberto wrote:

> In my mixing console overhaul I am using the following devices.
> OP275

The OP275 has this sentence: "This new front-end design combines both  
bipolar and JFET transistors to attain amplifiers with the accuracy  
and low noise performance of bipolar transistors, and the speed and  
sound quality of JFETs."

I've always wondered what they meant by the "sound quality of JFETs." ;)

- Aaron


From lanterma at ece.gatech.edu  Wed Apr 30 07:43:55 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 30 Apr 2008 01:43:55 -0400
Subject: [sdiy] Useful CV ranges for Buchla 191-style HPF
Message-ID: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>

While we're on the subject of damn fool crusades I've sent my students  
into, I've got another student looking at the idea of making a 4-pole  
HPF by taking an RC passive highpass filter, replacing the C with two  
diodes - one to a positive CV, and to the negative of that (changing  
the CV to change the dynamic resistance of the diodes), and then  
buffer that.

The Buchla 191 LPF uses this kind of HPF in a feedback loop of an op- 
amp-like-thing to form a lowpass shelf:

http://userdisk.webry.biglobe.ne.jp/000/024/65/N000/000/000/Buchla191vcf0707.GIF

Here, we're basically thinking about what's shown as Q6 and Q7 and C1,  
with the input going to C1, and an op amp replacing the Q3/Q4 buffer,  
and then having non of the goo in the upper left.

Here's a rough sketch I drew for my student, Thomas, to get him started:

http://users.ece.gatech.edu/~lanterma/buchla191_inspired_hpf.jpg

My thinking was:

1) A +/- 5V signal should be divided down to a "small AC" signal  
relative CVs used. I set up the op amp to get around +/- 0.2 V going  
into the filter. Does that sound like too much attenuation? Too  
little? I know the guidelines for an OTA but not sure what's best here.

2) On the diagram, the CV would go in the unlabeled pin at the 100K  
resistor in the bottom circuit. I thought that one could try CVs from  
a keyboard, so they might go up to 10 V. I somewhat arbitrarily (OK,  
totally arbitrarily) divided that by 10ish, so the CV at the diodes  
(which I'm calling CV*) would be between 0 and 1. Anyone have any  
intuition as to what a useful range of CV*s would be?

Thomas isn't getting any signal output at the moment, but I think  
there are wiring issues somewhere. While he's working that out, I  
figured I'd ask some questions along these lines.

Also, I should, as usual, ask if anyone sees anything completely nutty  
about my idea and/or schematic sketch.

- Aaron

P.S. Nobody will believe me, but I had the idea to build an LPF like  
this some time ago... I thought of it when thinking about the  
transistor-ladder to diode-ladder thinking, what would a diode version  
of the Moog HPF (which I never really understood) look like? Then a  
few years ago I had a student trying to build a LPF like this, using  
varactors replacing the Cs in an RC filter. That didn't work at all  
since it turns out varactors kinda suck at audio frequencies.


From lanterma at ece.gatech.edu  Wed Apr 30 07:47:48 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 30 Apr 2008 01:47:48 -0400
Subject: [sdiy] 1-pole LPF using a differential integrator?
In-Reply-To: <0701917A-720D-4CEC-84E5-49C3237FA441@ece.gatech.edu>
References: <10ED176D-2432-4B49-9C4E-927230194993@ece.gatech.edu>
	<0701917A-720D-4CEC-84E5-49C3237FA441@ece.gatech.edu>
Message-ID: <6A4E2718-16F5-45CD-AC7D-22075A6A6BD0@ece.gatech.edu>

On Apr 30, 2008, at 1:08 AM, Aaron Lanterman wrote:

> The NPN pair driving the differential integrator forms a variable  
> gain integrator with transfer function A/RCs, where A is the voltage  
> gain of the diff pair and R and C are the resistor values used in  
> the integrator. Let's denote wo = A/RC. Now imagine we take the  
> output of this integrator and feed it back into the input with a  
> minus sign. You get something like this:

Actually I think that should be wo = 2A/RC, since we're differencing  
two versions of the same signal with different signs (like in a Moog  
ladder). Hopefully this configuration should have the effect of  
cancelling out the common mode gain of the differential pair.

- Aaron


From lanterma at ece.gatech.edu  Wed Apr 30 07:51:23 2008
From: lanterma at ece.gatech.edu (Aaron Lanterman)
Date: Wed, 30 Apr 2008 01:51:23 -0400
Subject: [sdiy] Useful CV ranges for Buchla 191-style HPF
In-Reply-To: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
References: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
Message-ID: <AC5FB441-CC1E-46BD-93A7-6E4EFDE936B0@ece.gatech.edu>

On Apr 30, 2008, at 1:43 AM, Aaron Lanterman wrote:

> While we're on the subject of damn fool crusades I've sent my  
> students into, I've got another student looking at the idea of  
> making a 4-pole HPF by taking an RC passive highpass filter,  
> replacing the C with two diodes - one to a positive CV

I should not be e-mailing on no sleep. Of course I met replacing R  
with two diodes.

- Aaron


From dlmanley at sonic.net  Wed Apr 30 10:42:00 2008
From: dlmanley at sonic.net (Dave Manley)
Date: Wed, 30 Apr 2008 01:42:00 -0700
Subject: [sdiy] AN299 VCO
In-Reply-To: <0F274DE5-22A4-41BB-8CB1-98715B5EC8C3@embarqmail.com>
References: <48166E04.10707@gatech.edu>	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>	<000001c8aa02$a70135b0$f503a110$@net>
	<2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
	<48175D17.8090003@sonic.net>
	<0F274DE5-22A4-41BB-8CB1-98715B5EC8C3@embarqmail.com>
Message-ID: <481830D8.2090809@sonic.net>

Michael Bacich wrote:
>
> On Apr 29, 2008, at 10:38 AM, Dave Manley wrote:
>
>> I don't have reference materials at hand, but isn't a very similar 
>> circuit used in one of the later Moog VCOs?  I can dig it out tonight 
>> if there's interest.
>
> Yes, it's the MicroMoog VCO.  It uses at least one of the transistors 
> onboard the 3046 as a "heater", to heat the IC package up to just a 
> little above the typical expected ambient air temperature, making it 
> more immune to air temperature variations.  I'm not sure how it keeps 
> that transistor at a constant temperature, but the complete MicroMoog 
> service manual gives a very detailed circuit operation description.  
> I'm pretty sure that manual is available somewhere out there on the 
> web, but I don't know where.
>
> BTW, it's also the same VCO in the MultiMoog, and quite possibly also 
> in the Moog Rogue, Liberation, Prodigy, and Radio Shack MG-1 synth.  
> Each of those use the 3046 for the VCO core, and none of them utilize 
> Tempco resistors.  They're also amazingly stable -- probably much more 
> than an original MiniMoog VCO.
Hi Michael, I hope you don't mind me forwarding your response to the list.

I took a look, and the Lib, Micro, Multi, Source and Prodigy do use this 
method, and there are some slight differences in the circuits - mainly 
in how the heating transistor is controlled.  The Moog circuit is a bit 
different than AN-299 but the basic concept looks similar - I wonder 
which has precedence?

The combined MicroMoog/MultiMoog service manual gives a well written, 
detailed operational description.

Aaron, do your students do any SPICE analysis?  I'm not knocking the 
bench experience, there's nothing better than hands-on, but some of the 
what-if type questions you've been asking might benefit from 
simulation.  I'm sure you have access to some great tools there  at GA 
Tech, but the Linear Technology LTspice is a free, low learning curve 
tool, integrating schematic capture, simulation, and graphical output 
(you can even output .WAV files and listen to your simulation), with a 
very responsive Yahoo support group.  I wish I had access to such a 
product when I was in school.

-Dave




From pfperry at melbpc.org.au  Wed Apr 30 12:22:15 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 30 Apr 2008 20:22:15 +1000
Subject: [sdiy] AN299 VCO
In-Reply-To: <481830D8.2090809@sonic.net>
Message-ID: <002501c8aaac$106c9ef0$8501a8c0@ice9>

I always thought that Jim Williams used the self-heated & self-sensing
CA3046 first, when he was designing test gear at MIT. He started there in
1968, but I can't find whatever reference gave me the idea.

paul perry Melbourne Australia

-----Original Message-----
>I took a look, and the Lib, Micro, Multi, Source and Prodigy do use this 
>method, and there are some slight differences in the circuits - mainly 
>in how the heating transistor is controlled.  The Moog circuit is a bit 
>different than AN-299 but the basic concept looks similar - I wonder 
>which has precedence?



From tom at electricdruid.net  Wed Apr 30 12:31:11 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 30 Apr 2008 11:31:11 +0100
Subject: [sdiy] AN299 VCO
In-Reply-To: <481830D8.2090809@sonic.net>
References: <48166E04.10707@gatech.edu>	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>	<000001c8aa02$a70135b0$f503a110$@net>
	<2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
	<48175D17.8090003@sonic.net>
	<0F274DE5-22A4-41BB-8CB1-98715B5EC8C3@embarqmail.com>
	<481830D8.2090809@sonic.net>
Message-ID: <20992CD5-7195-466F-BBF8-94D93F12A853@electricdruid.net>


On 30 Apr 2008, at 09:42, Dave Manley wrote:

> The combined MicroMoog/MultiMoog service manual gives a well  
> written, detailed operational description.

Thanks for pointing me to that. I hadn't seen it before, and it's a  
great explanation of the technical side of Moog synths. Top stuff.

T.




From tom at electricdruid.net  Wed Apr 30 12:34:20 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 30 Apr 2008 11:34:20 +0100
Subject: [sdiy] Multi/MicroMoog (was AN299 VCO)
In-Reply-To: <481830D8.2090809@sonic.net>
References: <48166E04.10707@gatech.edu>	<5DDF087B-6618-4572-B85B-B6113C46D38E@ece.gatech.edu>	<000001c8aa02$a70135b0$f503a110$@net>
	<2818DAE4-0031-42F7-BA82-36A4AC251A15@electricdruid.net>
	<48175D17.8090003@sonic.net>
	<0F274DE5-22A4-41BB-8CB1-98715B5EC8C3@embarqmail.com>
	<481830D8.2090809@sonic.net>
Message-ID: <03401B2E-9144-4C72-BF0E-8AC5734FDF72@electricdruid.net>


On 30 Apr 2008, at 09:42, Dave Manley wrote:

> I took a look, and the Lib, Micro, Multi, Source and Prodigy do use  
> this method, and there are some slight differences in the circuits  
> - mainly in how the heating transistor is controlled.  The Moog  
> circuit is a bit different than AN-299 but the basic concept looks  
> similar - I wonder which has precedence?
>
> The combined MicroMoog/MultiMoog service manual gives a well  
> written, detailed operational description.

One more thing about these circuits:

The dreaded MM5837 digital noise chip comes puffing into view again!  
Everyone was at it, it seems. Even Moog.

T.



From tonyallgood at btinternet.com  Wed Apr 30 12:52:09 2008
From: tonyallgood at btinternet.com (Oakley Sound)
Date: Wed, 30 Apr 2008 11:52:09 +0100
Subject: [sdiy] AN299 VCO
In-Reply-To: <002501c8aaac$106c9ef0$8501a8c0@ice9>
References: <002501c8aaac$106c9ef0$8501a8c0@ice9>
Message-ID: <48184F59.30008@btinternet.com>

A badly implemented version is also in the early PPG 100 modular VCO. 
The one I saw never worked because the design was flawed. The circuit 
just didn't make sense. I couldn't see how it could ever work as it was 
built.

So I changed it to be more like the Prodigy design and then it worked 
just nicely. Quite a few track cuts and additional components were 
needed though.

But then there are a lot of issues with the PPG100. The power supply 
bussing is particularly poor.

Tony

www.oakleysound.com


From ijfritz at comcast.net  Wed Apr 30 13:06:19 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 30 Apr 2008 05:06:19 -0600
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <007c01c8aa57$654eaa30$8501a8c0@ice9>
References: <000001c8aa02$a70135b0$f503a110$@net>
	<007c01c8aa57$654eaa30$8501a8c0@ice9>
Message-ID: <6.2.1.2.2.20080430050215.0213ca08@mail.comcast.net>

At 06:16 PM 4/29/2008, Paul Perry wrote:
>Anyone using the CA3046 in feedback stabilized heater mode, note that the
>transistors in the chip have to be the same ones used in the application
>note.
>Although the transistors are identical electrically, because of the
>different physical placement in the chip, for the heater & sensor
>transistors to operate properly, I think they have to be as shown in the
>note.
>
>I haven't tried this circuit myself, but I seem to remember seeing something
>about this.

I've heard that too, but I don't understand it.  Aren't Q1 and Q2 the best 
matched pair, wherever they are located on the die?  I mean, on the wafer 
the matched pairs aren't always in the same relative location.

But the important point is that several list members have reported that the 
circuit works, so people shouldn't be put off from building it because of 
one or two failures.

Ian 



From pfperry at melbpc.org.au  Wed Apr 30 13:32:43 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 30 Apr 2008 21:32:43 +1000
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <6.2.1.2.2.20080430050215.0213ca08@mail.comcast.net>
Message-ID: <000b01c8aab5$e7f33f60$8501a8c0@ice9>

Certainly it works, by many accounts.
The thing is, it may not work, if one (for example) swaps the heating and
the temperature sensing transistors.
It's one of those things that one might think would not matter..
And, when laying out a PCB, it might be easier to lay out with them swapped.
I just mention this, to save someone being led astray.

As for the best matched pair - I find it hard to believe that the
transistors on the wafer are wired up differently according to where the
best pair is. That would make the chips very expensive indeed!

paul perry Melbourne australia

-----Original Message-----
From: Ian Fritz 

>I've heard that too, but I don't understand it.  Aren't Q1 and Q2 the best 
>matched pair, wherever they are located on the die?  I mean, on the wafer 
>the matched pairs aren't always in the same relative location.

>But the important point is that several list members have reported that the

>circuit works, so people shouldn't be put off from building it because of 
>one or two failures.




From ijfritz at comcast.net  Wed Apr 30 13:52:15 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 30 Apr 2008 05:52:15 -0600
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <000b01c8aab5$e7f33f60$8501a8c0@ice9>
References: <6.2.1.2.2.20080430050215.0213ca08@mail.comcast.net>
	<000b01c8aab5$e7f33f60$8501a8c0@ice9>
Message-ID: <6.2.1.2.2.20080430054212.020e0ec0@mail.comcast.net>

At 05:32 AM 4/30/2008, Paul Perry wrote:
>Certainly it works, by many accounts.
>The thing is, it may not work, if one (for example) swaps the heating and
>the temperature sensing transistors.
>It's one of those things that one might think would not matter..

Well, yeah!  The thermal conductivity of Si is very large.

But I haven't tried it, so I don't know.  But why couldn't you just 
increase the servo loop time constant and/or damping if the conductivity is 
an issue.


>As for the best matched pair - I find it hard to believe that the
>transistors on the wafer are wired up differently according to where the
>best pair is. That would make the chips very expensive indeed!

Maybe, but Q1 and Q2 are always way better matched than any other pair.  I 
found this out trying to make discrete transconductors, at which time I did 
extensive measurements of matching among the transistors.  So if you are 
correct, then it seems to me they would have to cut the dies so the matched 
pairs are always adjacent and in the same position.  Wouldn't this be 
pretty difficult?

:-)

Ian



From pfperry at melbpc.org.au  Wed Apr 30 14:08:58 2008
From: pfperry at melbpc.org.au (Paul Perry)
Date: Wed, 30 Apr 2008 22:08:58 +1000
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <6.2.1.2.2.20080430054212.020e0ec0@mail.comcast.net>
Message-ID: <000d01c8aaba$f85777e0$8501a8c0@ice9>

Well, I can't argue with actual measurements ;D

It is possible that the chips are selected, and the only transistors that
are checked for close matching are the pair in question - unlikely, though.
So many mysteries..

paul perry melb australia

-----Original Message-----
From: Ian Fritz 
>Maybe, but Q1 and Q2 are always way better matched than any other pair.  I 
>found this out trying to make discrete transconductors, at which time I did

>extensive measurements of matching among the transistors.  So if you are 
>correct, then it seems to me they would have to cut the dies so the matched

>pairs are always adjacent and in the same position.  Wouldn't this be 
>pretty difficult?
:-)
Ian



From rtellason at verizon.net  Wed Apr 30 14:55:18 2008
From: rtellason at verizon.net (Roy J. Tellason)
Date: Wed, 30 Apr 2008 08:55:18 -0400
Subject: [sdiy] Useful CV ranges for Buchla 191-style HPF
In-Reply-To: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
References: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
Message-ID: <200804300855.18411.rtellason@verizon.net>

On Wednesday 30 April 2008 01:43, Aaron Lanterman wrote:
> While we're on the subject of damn fool crusades I've sent my students
> into, I've got another student looking at the idea of making a 4-pole
> HPF by taking an RC passive highpass filter, replacing the C with two
> diodes - one to a positive CV, and to the negative of that (changing
> the CV to change the dynamic resistance of the diodes), and then
> buffer that.

For some reason this reminds me of the diode keying that was used in some 
organs.  The problem there is that you need really low signal amplitudes,  by 
comparison with your keying voltage.

> The Buchla 191 LPF uses this kind of HPF in a feedback loop of an op-
> amp-like-thing to form a lowpass shelf:
>
> http://userdisk.webry.biglobe.ne.jp/000/024/65/N000/000/000/Buchla191vcf070
>7.GIF
>
> Here, we're basically thinking about what's shown as Q6 and Q7 and C1,
> with the input going to C1, and an op amp replacing the Q3/Q4 buffer,
> and then having non of the goo in the upper left.
>
> Here's a rough sketch I drew for my student, Thomas, to get him started:
>
> http://users.ece.gatech.edu/~lanterma/buchla191_inspired_hpf.jpg
>
> My thinking was:
>
> 1) A +/- 5V signal should be divided down to a "small AC" signal
> relative CVs used. I set up the op amp to get around +/- 0.2 V going
> into the filter. Does that sound like too much attenuation? Too
> little? I know the guidelines for an OTA but not sure what's best here.

You don't want to get anywhere near turning those diodes on with the 
signal.  :-)

> 2) On the diagram, the CV would go in the unlabeled pin at the 100K
> resistor in the bottom circuit. I thought that one could try CVs from
> a keyboard, so they might go up to 10 V. I somewhat arbitrarily (OK,
> totally arbitrarily) divided that by 10ish, so the CV at the diodes
> (which I'm calling CV*) would be between 0 and 1. Anyone have any
> intuition as to what a useful range of CV*s would be?
>
> Thomas isn't getting any signal output at the moment, but I think
> there are wiring issues somewhere. While he's working that out, I
> figured I'd ask some questions along these lines.
>
> Also, I should, as usual, ask if anyone sees anything completely nutty
> about my idea and/or schematic sketch.
>
> - Aaron
>
> P.S. Nobody will believe me, but I had the idea to build an LPF like
> this some time ago... I thought of it when thinking about the
> transistor-ladder to diode-ladder thinking, what would a diode version
> of the Moog HPF (which I never really understood) look like? Then a
> few years ago I had a student trying to build a LPF like this, using
> varactors replacing the Cs in an RC filter. That didn't work at all
> since it turns out varactors kinda suck at audio frequencies.

It's not the frequency so much as the amplitude,  because with a varactor the 
signal is going to affect the capacitance as well as the control voltage,  so 
it would seem to me that they'd do pretty well when one is dealing with 
_very_ small signals,  as are typically found in RF circtuitry,  and not so 
much with the sort of signal levels we're going to find in synth gear,  which 
are normally higher than I see anywhere else.

Instead of buying parts specifcied for use as varactors,  you can also use 
ordinary rectifiers in a lot of cases,  too.  Or so I've read,  I haven't 
tried it.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin



From samppa.tolvanen at gmail.com  Wed Apr 30 15:08:37 2008
From: samppa.tolvanen at gmail.com (Samppa Tolvanen)
Date: Wed, 30 Apr 2008 16:08:37 +0300
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <000d01c8aaba$f85777e0$8501a8c0@ice9>
References: <6.2.1.2.2.20080430054212.020e0ec0@mail.comcast.net>
	<000d01c8aaba$f85777e0$8501a8c0@ice9>
Message-ID: <fa1b0bd80804300608t55ad01fcmf2aac3cb64cc0485@mail.gmail.com>

What's wrong With You Paul? Can't ARGUE over measurements? Hey, it's SDIY!
:D

On 4/30/08, Paul Perry <pfperry at melbpc.org.au> wrote:
> Well, I can't argue with actual measurements ;D
>
>  It is possible that the chips are selected, and the only transistors that
>  are checked for close matching are the pair in question - unlikely, though.
>  So many mysteries..
>
>
>  paul perry melb australia
>

I bet someone here has both -CA3086/CA3046s and electrone-microscope.. :)

Samppa


From c0r3dump23 at yahoo.com  Wed Apr 30 15:10:54 2008
From: c0r3dump23 at yahoo.com (Metrophage)
Date: Wed, 30 Apr 2008 06:10:54 -0700 (PDT)
Subject: [sdiy] Chinese MG-1s??!?
In-Reply-To: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
Message-ID: <215469.74040.qm@web63901.mail.re1.yahoo.com>


--- anthony <aankrom at bluemarble.net> wrote:

>  The filter is what makes the MG-1 golden.

What makes the filter golden is patching a VCO to modulate the top
octave chip, modulating the VCF cutoff with the LFO, and patching the
envelope to modulate the VCF resonance. Whee!


      ____________________________________________________________________________________
Be a better friend, newshound, and 
know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


From flightofharmony at comcast.net  Wed Apr 30 15:41:13 2008
From: flightofharmony at comcast.net (flightofharmony at comcast.net)
Date: Wed, 30 Apr 2008 13:41:13 +0000
Subject: [sdiy] More on the AN299 VCO
Message-ID: <043020081341.7523.481876F90000146600001D632209224627970201039D0E0800019B0809070400@comcast.net>

Okay, for some reason, I'm only able to post once a day. I've been trying to send this for about 24 hours now. So here's try #umpteenth.

To Samppa - 'You don't specify any figures for the drift.' - I didn't think to take measurements when I did it. The drift is pretty slow, I'd guess about 1Hz every 2-3 minutes after warming up. On the other hand, that's ludicrously fast for musical purposes! And it never stops.

~flight

From: flight [mailto:flightofharmony at comcast.net] 
Sent: Tuesday, April 29, 2008 7:27 AM
To: 'synth-diy at dropmix.xs4all.nl'
Subject: More on the AN299 VCO

I just remembered a few things:

The extra components on my schematic vs. the National schematic come from attempts to stabilize the thing. Most came from suggestions that were made the previous occasions this topic came up on Synth-DIY. I highly recommend the SDIY Searchable Archive: http://search.retrosynth.com/synth-diy/index.html

The saw standardizer is from  ?Musical Applications of Microprocessors? by Hal Chamberlin.

k, I think that?s it?

~flight


From flightofharmony at comcast.net  Wed Apr 30 15:52:30 2008
From: flightofharmony at comcast.net (flightofharmony at comcast.net)
Date: Wed, 30 Apr 2008 13:52:30 +0000
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
Message-ID: <043020081352.16202.4818799D000F37E500003F4A2200734076970201039D0E0800019B0809070400@comcast.net>

Ah-hah...

I hadn't even thought about that (newbie) - I might have to give it another try then, using the correct transistors.
It's a good little utility VCO with a clean waveform, worth a shot. Thanks!

~flight
 -------------- Original message ----------------------
From: "Paul Perry" <pfperry at melbpc.org.au>
> Anyone using the CA3046 in feedback stabilized heater mode, note that the
> transistors in the chip have to be the same ones used in the application
> note.
> Although the transistors are identical electrically, because of the
> different physical placement in the chip, for the heater & sensor
> transistors to operate properly, I think they have to be as shown in the
> note.
> 
> I haven't tried this circuit myself, but I seem to remember seeing something
> about this.
> 
> paul perry Melbourne Australia
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



From flightofharmony at comcast.net  Wed Apr 30 16:33:58 2008
From: flightofharmony at comcast.net (flightofharmony at comcast.net)
Date: Wed, 30 Apr 2008 14:33:58 +0000
Subject: [sdiy] More on the AN299 VCO 
Message-ID: <043020081433.25893.481883560000A1D1000065252209224627970201039D0E0800019B0809070400@comcast.net>

Here's the adjusted schematic with the proper transistor placement taken into account:

http://www.flightofharmony.com/stash/AN299_VCO_REV1.pdf

I just noticed something: When I first tried this, I assumed the inverted triangle supply symbols were ground since the App Note doesn't specify a negative voltage on the schematic. Did they mean -15V instead?

I'll go breadboard this (without the ancillary sections) and post the results.

~flight


From tom.corbitt at gmail.com  Wed Apr 30 17:08:39 2008
From: tom.corbitt at gmail.com (Tom Corbitt)
Date: Wed, 30 Apr 2008 11:08:39 -0400
Subject: [sdiy] Chinese MG-1s??!?
In-Reply-To: <215469.74040.qm@web63901.mail.re1.yahoo.com>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
Message-ID: <3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>

Looking at the design, the only gotcha I see is the 4 TOG chips, which
brings up a question I've seen asked over and over again on the list
archives.

What's the best way to recreate a TOG?

Best for me means:

#1 Cheap. if a chip costs over $10-$15 or so, I start thinking ""there
has to be a cheaper way  to do this"
#2 Simple. it doesn't have to be a drop in replacement, but I don't
want to replace 1 part with a sprawl of twenty+ parts.
#3 Future proof. I want something that I can carry forward in future
design. Sooner or later everything shuffles off to that great fab in
the sky, so I want to be able to move my process on to the next big
thing.

Looking at past answers, the general trend seems to be towards using
micros like pics to handle the dividing. I've seem the "old crow"
code, but I've yet to see a post where anyone indicated that they'd
taken this idea to completion and used it successfully to replace a
common top octave chip.  It would seem to me that this approach would
result in a square wave out, that you'd still need to filter back into
a sine before using it musically.

Am I wrong? What am I missing?

On Fri, 07 Jul 2006, Bob Weigel posted a followup  to a thread titled
"Top Octave Synthesizer" that ended with the following statement:
"There are much cheaper solutions for sdiy projects so if there's no
particular reason to need *that* one I'd look into something like
that. -bob " (He was referencing the S50240 chip)

What are the cheaper solutions he's speaking of? The one thing the TOG
seem great at it is keeping the system in global tune without a lot of
tricky sync work between subsystems.

Tom




On Wed, Apr 30, 2008 at 9:10 AM, Metrophage <c0r3dump23 at yahoo.com> wrote:
>
>  --- anthony <aankrom at bluemarble.net> wrote:
>
>  >  The filter is what makes the MG-1 golden.
>
>  What makes the filter golden is patching a VCO to modulate the top
>  octave chip, modulating the VCF cutoff with the LFO, and patching the
>  envelope to modulate the VCF resonance. Whee!
>
>
>
>       ____________________________________________________________________________________
>  Be a better friend, newshound, and
>  know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
>
>
> _______________________________________________
>  Synth-diy mailing list
>  Synth-diy at dropmix.xs4all.nl
>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


From houshu at muj.biglobe.ne.jp  Wed Apr 30 17:22:56 2008
From: houshu at muj.biglobe.ne.jp (HOSHUYAMA)
Date: Thu, 1 May 2008 00:22:56 +0900 (JST)
Subject: [sdiy] Useful CV ranges for Buchla 191-style HPF
In-Reply-To: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
References: <52B0A857-C046-4077-8856-A9FF790C64D5@ece.gatech.edu>
Message-ID: <20080430.235412.62265727.houshu@muj.biglobe.ne.jp>

Hello Aaron,

> http://users.ece.gatech.edu/~lanterma/buchla191_inspired_hpf.jpg

I tried a similar structure using diodes for APF not HPF, and failed ;-)
The reason I failed was signal coupling through CV*s,
which caused RF oscillation.
Voltage followers were not sufficient for decoupling when CV*s were high.

When with transistors, the signal coupling is much reduced: 

http://www5b.biglobe.ne.jp/~houshu/synth/Vchp0302.GIF

For CV cancellation, I used a feedback structure using U2 
instead of a simple inverting amplifier, because perfect 
complementary pair is not possible.

> Anyone have any  
> intuition as to what a useful range of CV*s would be?

I my case, the range was 0.3v to 0.55v.
Another issue is temparature compensation.
Q1 in the above schematic (Vchp0302.GIF) does the job.

Hope this helps.

Sam HOSHUYAMA
Saitama, JAPAN

Aaron Lanterman wrote:
> While we're on the subject of damn fool crusades I've sent my students  
> into, I've got another student looking at the idea of making a 4-pole  
> HPF by taking an RC passive highpass filter, replacing the C with two  
> diodes - one to a positive CV, and to the negative of that (changing  
> the CV to change the dynamic resistance of the diodes), and then  
> buffer that.
> 
> The Buchla 191 LPF uses this kind of HPF in a feedback loop of an op- 
> amp-like-thing to form a lowpass shelf:
> 
> 
> http://userdisk.webry.biglobe.ne.jp/000/024/65/N000/000/000/Buchla191vcf0707.GIF
> 
> Here, we're basically thinking about what's shown as Q6 and Q7 and C1,  
> with the input going to C1, and an op amp replacing the Q3/Q4 buffer,  
> and then having non of the goo in the upper left.
> 
> Here's a rough sketch I drew for my student, Thomas, to get him started:
> 
> 
> http://users.ece.gatech.edu/~lanterma/buchla191_inspired_hpf.jpg
> 
> My thinking was:
> 
> 1) A +/- 5V signal should be divided down to a "small AC" signal  
> relative CVs used. I set up the op amp to get around +/- 0.2 V going  
> into the filter. Does that sound like too much attenuation? Too  
> little? I know the guidelines for an OTA but not sure what's best here.
> 
> 2) On the diagram, the CV would go in the unlabeled pin at the 100K  
> resistor in the bottom circuit. I thought that one could try CVs from  
> a keyboard, so they might go up to 10 V. I somewhat arbitrarily (OK,  
> totally arbitrarily) divided that by 10ish, so the CV at the diodes  
> (which I'm calling CV*) would be between 0 and 1. Anyone have any  
> intuition as to what a useful range of CV*s would be?
> 
> Thomas isn't getting any signal output at the moment, but I think  
> there are wiring issues somewhere. While he's working that out, I  
> figured I'd ask some questions along these lines.
> 
> Also, I should, as usual, ask if anyone sees anything completely nutty  
> about my idea and/or schematic sketch.
> 
> - Aaron
> 
> P.S. Nobody will believe me, but I had the idea to build an LPF like  
> this some time ago... I thought of it when thinking about the  
> transistor-ladder to diode-ladder thinking, what would a diode version  
> of the Moog HPF (which I never really understood) look like? Then a  
> few years ago I had a student trying to build a LPF like this, using  
> varactors replacing the Cs in an RC filter. That didn't work at all  
> since it turns out varactors kinda suck at audio frequencies.
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> 
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
>  


From tom at electricdruid.net  Wed Apr 30 17:43:16 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 30 Apr 2008 16:43:16 +0100
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
Message-ID: <1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>


On 30 Apr 2008, at 16:08, Tom Corbitt wrote:

> What's the best way to recreate a TOG?
>
> Looking at past answers, the general trend seems to be towards using
> micros like pics to handle the dividing. I've seem the "old crow"
> code, but I've yet to see a post where anyone indicated that they'd
> taken this idea to completion and used it successfully to replace a
> common top octave chip.  It would seem to me that this approach would
> result in a square wave out, that you'd still need to filter back into
> a sine before using it musically.

You definitely get a squarewave output. I thought that was typical of  
TOG chips?
I've heard of some that produce a 30% duty cycle, whilst most are  
50%, but I've never
heard of a triangle or sine Top Octave chip.

The division ratios vary a bit depending on the master clock  
frequency, but here's a set for a 2MHz clock.

C low	?478
C#		?451
D		?426
D#		?402
E		?379
F		?358
F#		?338
G		?319
G#		?301
A		?284
A#		?268
B		?253
C high	?239

  2 MHz divided by 478 results in a frequency of 4184 Hz which is a  
C5 note
  2 MHz divided by 239 results in a frequency of 8368 Hz which is a  
C6 note (the highest one on the organ usually).

Obviously if you double the master clock frequency, you can also  
double the division ratios and keep the note outputs the same. Since  
you can then adjust not-quite-right ratios to odd numbers in-between,  
higher master clocks will give you better accuracy.

The Old Crow code produces the tones of an octave, but shifts it down  
a few octaves, which makes life much easier since it gives you more  
time to calculate the outputs. I don't know the detail on other  
processors (and maybe AVRs would be better for this job?) but the  
basic PICs will only run to 20MHz, with a 5MHz instruction cycle. If  
we ran the chip at 16MHz to give us a convenient 4MHz instruction  
cycle, we'd still need to get data out every other cycle.
I'm loathed to say it can't be done, since PIC hackers often just  
take that as a challenge and then prove you wrong, but if anyone can  
pull that off, it'd be an impressive effort.

If you were willing to accept some variation in duty-cycle between  
outputs, that might make life easier. Given the heavy filtering in  
most electronic organs, I doubt it'd be a huge issue.

It's definitely a tricky one, or someone would have managed already!

Regards,
Tom







>
> Am I wrong? What am I missing?
>
> On Fri, 07 Jul 2006, Bob Weigel posted a followup  to a thread titled
> "Top Octave Synthesizer" that ended with the following statement:
> "There are much cheaper solutions for sdiy projects so if there's no
> particular reason to need *that* one I'd look into something like
> that. -bob " (He was referencing the S50240 chip)
>
> What are the cheaper solutions he's speaking of? The one thing the TOG
> seem great at it is keeping the system in global tune without a lot of
> tricky sync work between subsystems.
>
> Tom
>
>
>
>
> On Wed, Apr 30, 2008 at 9:10 AM, Metrophage <c0r3dump23 at yahoo.com>  
> wrote:
>>
>>  --- anthony <aankrom at bluemarble.net> wrote:
>>
>>>  The filter is what makes the MG-1 golden.
>>
>>  What makes the filter golden is patching a VCO to modulate the top
>>  octave chip, modulating the VCF cutoff with the LFO, and patching  
>> the
>>  envelope to modulate the VCF resonance. Whee!
>>
>>
>>
>>        
>> _____________________________________________________________________ 
>> _______________
>>  Be a better friend, newshound, and
>>  know-it-all with Yahoo! Mobile.  Try it now.  http:// 
>> mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
>>
>>
>> _______________________________________________
>>  Synth-diy mailing list
>>  Synth-diy at dropmix.xs4all.nl
>>  http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>





From jpdesroc at oricom.ca  Wed Apr 30 17:48:56 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Wed, 30 Apr 2008 11:48:56 -0400
Subject: [sdiy] MAT Amp synth supply connector suggestions..
Message-ID: <380-220084330154856476@oricom.ca>


Hi list,
I'm about to chose a 'specific' pinout for
my future MAT synth supply connectors..
I'll probably use AMP 640445-x type PCB male connectors.
The number of pins is to be found..
I'll surely use some microcontrolers in some modules
with the analog chips.
 
I'm thinking of these possible pin arrangements:
 
#    function
1    +15v
2    GND
3    -15v
4    +5v (digital)
 
or this
 
#    function
1    +15v
2    GND
3    GND
4    -15v
 
or this
 
#    function
1    +15v
2    analog GND
3    -15v
4    digital GND
5    +5v (digital supply)
 
The modules supply cables will be made of #18 AWG stranded wires.
The the wires colors... not yet chosen.
Any suggestions?
Thanks
JP





From neil.johnson97 at ntlworld.com  Wed Apr 30 17:51:04 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 30 Apr 2008 15:51:04 +0000
Subject: [sdiy] More on the AN299 VCO
Message-ID: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@smtp.ntlworld.com>

Hi,

From: flightofharmony at comcast.net
> 
> Here's the adjusted schematic with the proper transistor placement taken into account:
> 
> http://www.flightofharmony.com/stash/AN299_VCO_REV1.pdf
> 
> I just noticed something: When I first tried this, I assumed the inverted triangle supply symbols were ground since the App Note doesn't specify a negative voltage on the schematic. Did they mean -15V instead?
> 
> I'll go breadboard this (without the ancillary sections) and post the results.

Apologies if this has already been discussed, but it seems to me that you have IC2A the wrong way round when compared to the schematic in AN-299.

Neil


--
http://www.njohnson.co.uk

-----------------------------------------
Email sent from www.virginmedia.com/email
Virus-checked using McAfee(R) Software and scanned for spam



From music.maker at gte.net  Wed Apr 30 17:52:37 2008
From: music.maker at gte.net (Scott Gravenhorst)
Date: Wed, 30 Apr 2008 08:52:37 -0700
Subject: [sdiy] Chinese MG-1s??!?
Message-ID: <200804301552.m3UFqb4Z028242@linux7.lan>

"Tom Corbitt" <tom.corbitt at gmail.com> wrote:
>Looking at the design, the only gotcha I see is the 4 TOG chips, which
>brings up a question I've seen asked over and over again on the list
>archives.
>
>What's the best way to recreate a TOG?
>
>Best for me means:
>
>#1 Cheap. if a chip costs over $10-$15 or so, I start thinking ""there
>has to be a cheaper way  to do this"
>#2 Simple. it doesn't have to be a drop in replacement, but I don't
>want to replace 1 part with a sprawl of twenty+ parts.
>#3 Future proof. I want something that I can carry forward in future
>design. Sooner or later everything shuffles off to that great fab in
>the sky, so I want to be able to move my process on to the next big
>thing.
>
>Looking at past answers, the general trend seems to be towards using
>micros like pics to handle the dividing. I've seem the "old crow"
>code, but I've yet to see a post where anyone indicated that they'd
>taken this idea to completion and used it successfully to replace a
>common top octave chip.  It would seem to me that this approach would
>result in a square wave out, that you'd still need to filter back into
>a sine before using it musically.
>
>Am I wrong? What am I missing?

All TOG devices produce rectangular outputs.  A TOG synth also prevents subtle tuning
changes as one moves from one octave to another.  These tuning changes can change and
enhance the character of the synth.

If you're looking to repair a broken vintage synth that contains TOG ICs, I think #2
is doable, I believe someone here has tested a CPLD (or 2) and others have suggested
PIC or other microprocessor.  However, you can still run into problems interfacing a
modern device into and older design because of differences in expected voltages -
adding to the cost.

The key is to find a single programmable digital device large enough to handle the
hundreds of flipflops inside the TOG.  This will determine minimum the number of
devices required to emulate the original TOG.  This and the fact the field
programmable devices (CPLD, PIC, etc) require a programmer affect the cost.

IMO, #3 is unattainable, nothing is future-proof.

If you're doing something new, then you might consider a full digital approach, such
as an FPGA which can be reprogrammed to become whatever you need at the moment.  Both
poly and monosynths are possible in an FPGA.  Not "cheap", but when you consider the
fact that the device is re-usable for many purposes, the moderate cost of a dev board
isn't that much.

>On Fri, 07 Jul 2006, Bob Weigel posted a followup  to a thread titled
>"Top Octave Synthesizer" that ended with the following statement:
>"There are much cheaper solutions for sdiy projects so if there's no
>particular reason to need *that* one I'd look into something like
>that. -bob " (He was referencing the S50240 chip)
>
>What are the cheaper solutions he's speaking of? The one thing the TOG
>seem great at it is keeping the system in global tune without a lot of
>tricky sync work between subsystems.

Maybe Bob can point you in the direction of these "much cheaper solutions".

Digital synths typically have this "in tune" character.

-- ScottG

-----------------------------------------------------------------

-- Scott Gravenhorst
-- GateMan-III - FPGA Based Monophonic MIDI Synthesizer with SVF
-- PolyDaWG/8 - FPGA Based 8 Voice Polyphonic MIDI Synthesizer
-- phLUTe - FPGA Based Monophonic Physical Model MIDI Synthesizer
-- FatMan: home1.gte.net/res0658s/fatman/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- When the going gets tough, the tough use the command line.



From chris at chrismusic.de  Wed Apr 30 18:11:54 2008
From: chris at chrismusic.de (ChristianH)
Date: Wed, 30 Apr 2008 18:11:54 +0200
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
References: <3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
Message-ID: <20080430180030.C198.CHRIS@chrismusic.de>

and, since those micro controller chips are dirt cheap, you could
distribute the 13 channels to 3 or 4 ATtiny processors (there are 8 pin
DIP versions). Running at 16 MHz, it should be feasible to do some 4
counters and port output in a 2 MHz loop.

Chris



On Wed, 30 Apr 2008 16:43:16 +0100 Tom Wiltshire <tom at electricdruid.net>
wrote:

> You definitely get a squarewave output. I thought that was typical of  
> TOG chips?
> I've heard of some that produce a 30% duty cycle, whilst most are  
> 50%, but I've never
> heard of a triangle or sine Top Octave chip.
> 
> The division ratios vary a bit depending on the master clock  
> frequency, but here's a set for a 2MHz clock.
> 
> C low	?478
> C#		?451
> D		?426
> D#		?402
> E		?379
> F		?358
> F#		?338
> G		?319
> G#		?301
> A		?284
> A#		?268
> B		?253
> C high	?239
> 
>   2 MHz divided by 478 results in a frequency of 4184 Hz which is a  
> C5 note
>   2 MHz divided by 239 results in a frequency of 8368 Hz which is a  
> C6 note (the highest one on the organ usually).
> 
> Obviously if you double the master clock frequency, you can also  
> double the division ratios and keep the note outputs the same. Since  
> you can then adjust not-quite-right ratios to odd numbers in-between,  
> higher master clocks will give you better accuracy.
> 
> The Old Crow code produces the tones of an octave, but shifts it down  
> a few octaves, which makes life much easier since it gives you more  
> time to calculate the outputs. I don't know the detail on other  
> processors (and maybe AVRs would be better for this job?) but the  
> basic PICs will only run to 20MHz, with a 5MHz instruction cycle. If  
> we ran the chip at 16MHz to give us a convenient 4MHz instruction  
> cycle, we'd still need to get data out every other cycle.
> I'm loathed to say it can't be done, since PIC hackers often just  
> take that as a challenge and then prove you wrong, but if anyone can  
> pull that off, it'd be an impressive effort.
> 
> If you were willing to accept some variation in duty-cycle between  
> outputs, that might make life easier. Given the heavy filtering in  
> most electronic organs, I doubt it'd be a huge issue.
> 
> It's definitely a tricky one, or someone would have managed already!
> 
> Regards,
> Tom
> 
> 
> 
> 
> 
> 
> 
> >
> > Am I wrong? What am I missing?
> >
> > On Fri, 07 Jul 2006, Bob Weigel posted a followup  to a thread titled
> > "Top Octave Synthesizer" that ended with the following statement:
> > "There are much cheaper solutions for sdiy projects so if there's no
> > particular reason to need *that* one I'd look into something like
> > that. -bob " (He was referencing the S50240 chip)
> >
> > What are the cheaper solutions he's speaking of? The one thing the TOG
> > seem great at it is keeping the system in global tune without a lot of
> > tricky sync work between subsystems.
> >
> > Tom




From neil.johnson97 at ntlworld.com  Wed Apr 30 18:30:43 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 30 Apr 2008 16:30:43 +0000
Subject: [sdiy] MAT Amp synth supply connector suggestions..
Message-ID: <20080430162937.XXWF29112.aamtaout04-winn.ispmail.ntl.com@smtp.ntlworld.com>

Hi,

Personally I'd go for option 2:

> #    function
> 1    +15v
> 2    GND
> 3    GND
> 4    -15v

and locally generate +5V for micro/logic with a linear regulator.

Colours: +15V = red, GND = black, -15V = blue

But that's just my opinion :)

Neil


--
http://www.njohnson.co.uk

-----------------------------------------
Email sent from www.virginmedia.com/email
Virus-checked using McAfee(R) Software and scanned for spam



From richard at atkinsoft.com  Wed Apr 30 18:33:15 2008
From: richard at atkinsoft.com (Richard Atkinson)
Date: 30 Apr 2008 17:33:15 +0100
Subject: TOG chips Re: [sdiy] Chinese MG-1s??!?
In-Reply-To: <200804301552.m3UFqb4Z028242@linux7.lan>
References: <200804301552.m3UFqb4Z028242@linux7.lan>
Message-ID: <Prayer.1.1.0.0804301733150.25115@hermes-1.csi.cam.ac.uk>

On Apr 30 2008, Scott Gravenhorst wrote:

> If you're looking to repair a broken vintage synth that contains TOG ICs, 
> I think #2 is doable, I believe someone here has tested a CPLD (or 2) and 
> others have suggested PIC or other microprocessor. However, you can still 
> run into problems interfacing a modern device into and older design 
> because of differences in expected voltages - adding to the cost.
>
> The key is to find a single programmable digital device large enough to 
> handle the hundreds of flipflops inside the TOG. This will determine 
> minimum the number of devices required to emulate the original TOG. This 
> and the fact the field programmable devices (CPLD, PIC, etc) require a 
> programmer affect the cost.

I'm about to start work on a Godwin String Concert which has non-working 
D#/Eb keys. I'm dreading the prospect of having to replace the TOG chip, 
and hoping for some sort of miracle such as a dry joint or a duff capacitor 
etc. All four of the keys (in each octave) don't work, at all footages.

Anyone know which TOG chip the Godwin String Concert uses?

Richard



From jpdesroc at oricom.ca  Wed Apr 30 18:46:56 2008
From: jpdesroc at oricom.ca (jpdesroc at oricom.ca)
Date: Wed, 30 Apr 2008 12:46:56 -0400
Subject: [sdiy] MAT Amp synth supply connector 
Message-ID: <380-22008433016465686@oricom.ca>

Sorry I forgot to say I'm gonna use a supply that has:
+-15v at 3amp
+5v at 5amp
So I won't generate +5v using a reg at local +15v
since I already have it.
This would also rise up at the end the overall +15v
rail DC current.

Any suggestions welcome for the pin configuration.
JP




From veronica.merryfield at shaw.ca  Wed Apr 30 19:22:24 2008
From: veronica.merryfield at shaw.ca (Veronica Merryfield)
Date: Wed, 30 Apr 2008 10:22:24 -0700
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
Message-ID: <9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>

>
> The division ratios vary a bit depending on the master clock  
> frequency, but here's a set for a 2MHz clock.
>
> C low	?478
> C#		?451
> D		?426
> D#		?402
> E		?379
> F		?358
> F#		?338
> G		?319
> G#		?301
> A		?284
> A#		?268
> B		?253
> C high	?239
>
> 2 MHz divided by 478 results in a frequency of 4184 Hz which is a C5  
> note
> 2 MHz divided by 239 results in a frequency of 8368 Hz which is a C6  
> note (the highest one on the organ usually).
>
> Obviously if you double the master clock frequency, you can also  
> double the division ratios and keep the note outputs the same. Since  
> you can then adjust not-quite-right ratios to odd numbers in- 
> between, higher master clocks will give you better accuracy.
>
> The Old Crow code produces the tones of an octave, but shifts it  
> down a few octaves, which makes life much easier since it gives you  
> more time to calculate the outputs. I don't know the detail on other  
> processors (and maybe AVRs would be better for this job?) but the  
> basic PICs will only run to 20MHz, with a 5MHz instruction cycle. If  
> we ran the chip at 16MHz to give us a convenient 4MHz instruction  
> cycle, we'd still need to get data out every other cycle.
> I'm loathed to say it can't be done, since PIC hackers often just  
> take that as a challenge and then prove you wrong, but if anyone can  
> pull that off, it'd be an impressive effort.
>
> If you were willing to accept some variation in duty-cycle between  
> outputs, that might make life easier. Given the heavy filtering in  
> most electronic organs, I doubt it'd be a huge issue.
>
> It's definitely a tricky one, or someone would have managed already!

The way to make this work is not to have 12 dividers but to use a  
rolling scheduler.

You have a table of structures, the first entry is the number of  
'ticks' you need to wait before generating the event and the second  
entry is the event specifier (probably a number indicting a port pin).  
The tick could be a timer. When the tick happens, the event is  
produced and it expires. The software inserts the next event of this  
type into the queue using the division ratio to place it then  
calculating the count from the previous entry as it's count and  
updating the next entry to subtract that amount out of it's count. I  
would use 24 events in all, one of each edge of each output. A little  
intelligence will be needed to handle events that come close together.  
If you can use a micro that has a single timer with interrupt then it  
is a sequence of single shot timer events. If not, then you need some  
way to count processor cycles and carefully crafted code.

I'm not going to volunteer to write it as I have too much else on, but  
I have done very similar things in small processors with a lot more  
work to do between events and setting events - it's how ECUs work.

Veronica




From manuel at bl0rg.net  Wed Apr 30 19:35:39 2008
From: manuel at bl0rg.net (Manuel Odendahl)
Date: Wed, 30 Apr 2008 19:35:39 +0200
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
	<9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
Message-ID: <AF4A5AF0-0E01-4F0F-B649-D4003854DD18@bl0rg.net>

On Apr 30, 2008, at 7:22 PM, Veronica Merryfield wrote:
>> C low	?478
>> C#		?451
>> D		?426
>> D#		?402
>> E		?379
>> F		?358
>> F#		?338
>> G		?319
>> G#		?301
>> A		?284
>> A#		?268
>> B		?253
>> C high	?239

Untested idea, but as the ratios are fixed, you could write some long  
main loop being basically a sequence of nop loops interspersed with  
various bit banging calls to set the output frequencies at the right  
times, and then just run the input of the TOG as the oscillator of the  
microcontroller.

It would be like

239 nops
set C high
13 nops
set B
14 nops
set A#
etc...

(I skipped the clearing, but you get the idea).

Btw, hello everybody, I'm new to the list :)

Regards, Manuel
>>



From manuel at bl0rg.net  Wed Apr 30 19:49:39 2008
From: manuel at bl0rg.net (Manuel Odendahl)
Date: Wed, 30 Apr 2008 19:49:39 +0200
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <AF4A5AF0-0E01-4F0F-B649-D4003854DD18@bl0rg.net>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
	<9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
	<AF4A5AF0-0E01-4F0F-B649-D4003854DD18@bl0rg.net>
Message-ID: <CD1E0DB0-7FE6-42E1-B0A4-5D993F7DE07F@bl0rg.net>


On Apr 30, 2008, at 7:35 PM, Manuel Odendahl wrote:
> Untested idea, but as the ratios are fixed, you could write some  
> long main loop being basically a sequence of nop loops interspersed  
> with various bit banging calls to set the output frequencies at the  
> right times, and then just run the input of the TOG as the  
> oscillator of the microcontroller.

Forget this, veronica is right... :) I should have a cup of coffee  
before reading emails.

Cheers, Manuel


From aankrom at bluemarble.net  Wed Apr 30 19:55:02 2008
From: aankrom at bluemarble.net (anthony)
Date: Wed, 30 Apr 2008 13:55:02 -0400
Subject: [sdiy] Tube microphonics: 12SQ7GT & 12AV6, 6SN7GT & 6CG7/6FQ7,
	etc.
References: <007c01c8aa57$654eaa30$8501a8c0@ice9><018b01c8aa64$ba534510$0202a8c0@positronium>
	<000b01c8aa74$479b2fa0$6401a8c0@cyberup0n1qn6z>
Message-ID: <01a101c8aaeb$525137b0$0202a8c0@positronium>

I always consider my tube questions to be on topic here because I use tube 
amps with synth gear. And I think of electric organs, whether they be 
electromechanical like Hammonds or many many tube monstrosities like 
Wurlitzers & other less complicated tube-based organs as falling under the 
the topic of synth-DIY if someone plans on recreating part of the organ or 
integrating a partially functioning organ into a modular synth system, as 
synthesizers of a sort.

One of the amps I have in the works is intended to be used with my MKS-50 as 
is another stereo amp that will be used to amplify the output of a DJ mixer 
connected to two different modular synths (yet to be finished) both equiped 
with sequencers. The synths will have their own tube reverbs and the amp 
will have 2 of its own reverbs. So that's a lot fo tube circuitry for synth 
work.

So I think a lot about tube circuitry a lot when I am building my synth 
gear. Especially since I have so many random little tube preamps that find 
synth or vocal uses.

A lot of you have proven knowledgeable about tube circuitry in the past.

I haven't been on Usenet in forever since before the web existed as such 
really. But I think the appeal that this group has still applies there I 
hope: you can almosty always depend on a few quick replies. Webpage-based 
forums not so much.

Would I have to wade through a lot of audiophile prejudices on 
rec.audio.tubes? I guess it's not called 
rec.audio.tubes.direct-heated-cathodes-only...

anthony


>> I have been thinking about tube microphonics lately and was wondering 
>> what
>> aspects of the physical parts of the tube, like length of getter 
>> supports,
>> getter position & shape, wire thickness, placement of mica supports and 
>> so
>> on.
>>
> It depends on the tube's intended use. Some circuits aren't affected by
> microphony. Not all tubes are great for audio. Plus you have to remember
> that most of the oddball types have been shuffled around for 30-50 years 
> so
> the internal structure may be compromised.
>
> A 6CG7 can be a decent low power output amp if you think outside the box a
> little. Ampeg used them as capacitive coupled reverb coil drivers.
>
> Other than that, post in usenet group rec.audio.tubes.....thats the place
> where all the "toobs" hang out. You'll get far more info there and it'll 
> be
> on topic.
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> 




From ebrombaugh at earthlink.net  Wed Apr 30 19:57:23 2008
From: ebrombaugh at earthlink.net (Eric Brombaugh)
Date: Wed, 30 Apr 2008 10:57:23 -0700
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>	<215469.74040.qm@web63901.mail.re1.yahoo.com>	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
	<9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
Message-ID: <4818B303.20503@earthlink.net>

Veronica Merryfield wrote:

> The way to make this work is not to have 12 dividers but to use a 
> rolling scheduler.

Very nice approach.

> A little intelligence will be needed to handle 
> events that come close together.

You said a mouthful there. Traversing the queue to schedule the next 
instance of the current edge, then fetching the top of the queue to set 
the timer for the next event is probably going to eat up enough time to 
make event crowding a very real issue. A fun problem for someone. :)

Eric



From tom at electricdruid.net  Wed Apr 30 20:10:15 2008
From: tom at electricdruid.net (Tom Wiltshire)
Date: Wed, 30 Apr 2008 19:10:15 +0100
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <CD1E0DB0-7FE6-42E1-B0A4-5D993F7DE07F@bl0rg.net>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
	<9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
	<AF4A5AF0-0E01-4F0F-B649-D4003854DD18@bl0rg.net>
	<CD1E0DB0-7FE6-42E1-B0A4-5D993F7DE07F@bl0rg.net>
Message-ID: <5FDFB5A2-81C2-440C-805A-2C84028A2E9E@electricdruid.net>


On 30 Apr 2008, at 18:49, Manuel Odendahl wrote:

>
> On Apr 30, 2008, at 7:35 PM, Manuel Odendahl wrote:
>> Untested idea, but as the ratios are fixed, you could write some  
>> long main loop being basically a sequence of nop loops  
>> interspersed with various bit banging calls to set the output  
>> frequencies at the right times, and then just run the input of the  
>> TOG as the oscillator of the microcontroller.
>
> Forget this, veronica is right... :) I should have a cup of coffee  
> before reading emails.

It's a nice idea, but that 'long main loop' is going to be *very*  
long before all of those frequencies line up again.

I think Chris is probably right, and it's easiest to simply split the  
work onto a few chips. Stil, a one-chip wonder would be nice...;-)

T.




From neil.johnson97 at ntlworld.com  Wed Apr 30 20:27:30 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 30 Apr 2008 19:27:30 +0100
Subject: [sdiy] MAT Amp synth supply connector 
In-Reply-To: <380-22008433016465686@oricom.ca>
References: <380-22008433016465686@oricom.ca>
Message-ID: <414446BF-D8A8-4AC1-BE34-D6A3485D5AAF@ntlworld.com>

Hi,

jpdesroc at oricom.ca wrote:

> Sorry I forgot to say I'm gonna use a supply that has:
> +-15v at 3amp
> +5v at 5amp

Ah, well in that case you may well use the +5V.  But...

> So I won't generate +5v using a reg at local +15v
> since I already have it.

This would help spread digital noise through the synth.

> This would also rise up at the end the overall +15v
> rail DC current.

By not much though.  Perhaps 100mA for a hungry digital circuit?

Neil
--
http://www.njohnson.co.uk





From flightofharmony at comcast.net  Wed Apr 30 20:35:04 2008
From: flightofharmony at comcast.net (flightofharmony at comcast.net)
Date: Wed, 30 Apr 2008 18:35:04 +0000
Subject: [sdiy] More on the AN299 VCO
Message-ID: <043020081835.4338.4818BBD8000AEF4B000010F22200735834970201039D0E0800019B0809070400@comcast.net>

Oops, thanks! I should know better than to do this so early in the morning.

It's corrected now, and I'm running the circuit to get some drift measurements - It's running much better than before, but it is still drifting slowly (open-air, nylon protoboard). This might just be due to the warm-up period.

~flight
 -------------- Original message ----------------------
From: Neil Johnson <neil.johnson97 at ntlworld.com>
> Hi,
> 
> From: flightofharmony at comcast.net
> > 
> > Here's the adjusted schematic with the proper transistor placement taken into 
> account:
> > 
> > http://www.flightofharmony.com/stash/AN299_VCO_REV1.pdf
> > 
> > I just noticed something: When I first tried this, I assumed the inverted 
> triangle supply symbols were ground since the App Note doesn't specify a 
> negative voltage on the schematic. Did they mean -15V instead?
> > 
> > I'll go breadboard this (without the ancillary sections) and post the results.
> 
> Apologies if this has already been discussed, but it seems to me that you have 
> IC2A the wrong way round when compared to the schematic in AN-299.
> 
> Neil
> 
> 
> --
> http://www.njohnson.co.uk
> 
> -----------------------------------------
> Email sent from www.virginmedia.com/email
> Virus-checked using McAfee(R) Software and scanned for spam
> 



From Stromeko at nexgo.de  Wed Apr 30 20:48:16 2008
From: Stromeko at nexgo.de (ASSI)
Date: Wed, 30 Apr 2008 20:48:16 +0200
Subject: [sdiy] Chinese MG-1s??!?
In-Reply-To: <3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
Message-ID: <200804302048.16313.Stromeko@nexgo.de>

On Mittwoch 30 April 2008, Tom Corbitt wrote:
> Looking at the design, the only gotcha I see is the 4 TOG chips,
> which brings up a question I've seen asked over and over again on the
> list archives.
>
> What's the best way to recreate a TOG?

GAL/CPLD/FPGA, depending on inclination and purpose; i.e. do you want to 
replace existing chips or just implement something "along the lines of 
whatever".  Depending on the size of the chip you might even get all 
four TOG into the same package if you want to.  While microprocessors 
can do this when they are fast enough, the cheap ones aren't really 
made to provide a bunch of phase-locked signals from a single clock.  
Since that isn't really a desirable property for a musical instrument, 
this could actually be advantageous, but I'd still rather use real 
logic to losen up the phases.

Something like this would be helpful if you don't want to deal with SMD 
parts, however the CPLD are also still available PLCC packages (more 
expensive, then):
http://www.digilentinc.com/Products/Detail.cfm?Prod=CMOD

The TOG don't always have simple squarewaves as their output, see:

http://www.organservice.com/crm/topdividers.htm

A complete TOG needs a rather large CPLD and if you want to do something 
about the phase locking I'd go straight to an FPGA with enough pins to 
produce all note outputs simultaneously.  There is enough extra logic 
left to do things like breaking up the phase-lock, varying ouput 
pulsewidth, providing vibrato and different tunings.

The divider chips in the MG-1 seem to be simply 6 toggle FF in DIL-14 
though, so if you want to replace those a simple 16V8 has more then 
enough resources, but needs an interposer to get the number and 
position of pins correct.  The smallest of the CPLD would replace the 
complete set of four MM5823, but if you insist on using the 5V version 
it's a tiny bit more expensive than four 16V8 (a 3.3V CPLD is cheaper 
than a 5V GAL, though).


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

SD adaptation for Waldorf microQ V2.22R2:
http://Synth.Stromeko.net/Downloads.html#WaldorfSDada



From Stromeko at nexgo.de  Wed Apr 30 20:48:39 2008
From: Stromeko at nexgo.de (ASSI)
Date: Wed, 30 Apr 2008 20:48:39 +0200
Subject: [sdiy] AN299 VCO (was: SDIY list troubles)
In-Reply-To: <6.2.1.2.2.20080430050215.0213ca08@mail.comcast.net>
References: <000001c8aa02$a70135b0$f503a110$@net>
	<007c01c8aa57$654eaa30$8501a8c0@ice9>
	<6.2.1.2.2.20080430050215.0213ca08@mail.comcast.net>
Message-ID: <200804302048.39746.Stromeko@nexgo.de>

On Mittwoch 30 April 2008, Ian Fritz wrote:
> I've heard that too, but I don't understand it.  Aren't Q1 and Q2 the
> best matched pair, wherever they are located on the die?  I mean, on
> the wafer the matched pairs aren't always in the same relative
> location.

They should always be in the same place of the die, it's a monolithic 
transistor array after all.  I've never heard of anyone changing a 
bonding plan based on the measurement of whatever parameter and it 
would certainly be almost impossible to do on a DIP leadframe even if 
you wanted to.  It may well be that the matching between different 
transistors could be noticeably different, but that would be a function 
of layout just and should therefore be pretty consistent.

On Mittwoch 30 April 2008, Samppa Tolvanen wrote:
> I bet someone here has both -CA3086/CA3046s and
> electrone-microscope.. :)

I lack the former, but have access to the latter.  But I don't think you 
need a REM for these, in fact it would be quite difficult to use on 
such large structures.  I'd expect these transistors to be somewhat 
larger than the LM13600 pictured at http://www.idea2ic.com/ - plain 
optical at ~50x magnification would suffice.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

Factory and User Sound Singles for Waldorf rackAttack:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds



From ijfritz at comcast.net  Wed Apr 30 20:55:07 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 30 Apr 2008 12:55:07 -0600
Subject: [sdiy] More on the AN299 VCO
In-Reply-To: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@s
	mtp.ntlworld.com>
References: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@smtp.ntlworld.com>
Message-ID: <6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>

At 09:51 AM 4/30/2008, Neil Johnson wrote:


>Apologies if this has already been discussed, but it seems to me that you 
>have IC2A the wrong way round when compared to the schematic in AN-299.


AN299 does not specify which transistor in the schematic is which in the array!

You can easily see this by the fact that Q6 is part of the array, which, of 
course, only has five transistors.

Ian  



From flightofharmony at comcast.net  Wed Apr 30 21:26:22 2008
From: flightofharmony at comcast.net (flightofharmony at comcast.net)
Date: Wed, 30 Apr 2008 19:26:22 +0000
Subject: [sdiy] More on the AN299 VCO
Message-ID: <043020081926.17407.4818C7DE00060556000043FF2200750784970201039D0E0800019B0809070400@comcast.net>

Which is why it didn't work well the first time around!

This time, I assumed that Q6 in the App Note would correspond to Q5 in the array. So far, it's been pretty stable: after one hour running in open air it has only shifted by ~1.5Hz. I'm assuming proper thermal insulation in a closed box would cure that.

The remaining problem is the max. frequency is around 1950 Hz, then it latches until the CV is lowered. I had this problem the first time as well, any ideas? BTW - I'm using a TL082.


 -------------- Original message ----------------------
From: Ian Fritz <ijfritz at comcast.net>
> At 09:51 AM 4/30/2008, Neil Johnson wrote:
> 
> 
> >Apologies if this has already been discussed, but it seems to me that you 
> >have IC2A the wrong way round when compared to the schematic in AN-299.
> 
> 
> AN299 does not specify which transistor in the schematic is which in the array!
> 
> You can easily see this by the fact that Q6 is part of the array, which, of 
> course, only has five transistors.
> 
> Ian  
> 



From ijfritz at comcast.net  Wed Apr 30 21:49:09 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 30 Apr 2008 13:49:09 -0600
Subject: [sdiy] More on the AN299 VCO
In-Reply-To: <043020081926.17407.4818C7DE00060556000043FF220075078497020
	1039D0E0800019B0809070400@comcast.net>
References: <043020081926.17407.4818C7DE00060556000043FF2200750784970201039D0E0800019B0809070400@comcast.net>
Message-ID: <6.2.1.2.2.20080430133820.020f5768@mail.comcast.net>

At 01:26 PM 4/30/2008, flightofharmony at comcast.net wrote:
>Which is why it didn't work well the first time around!

So ... you were heating the reset transistors?


>This time, I assumed that Q6 in the App Note would correspond to Q5 in the 
>array. So far, it's been pretty stable: after one hour running in open air 
>it has only shifted by ~1.5Hz. I'm assuming proper thermal insulation in a 
>closed box would cure that.

I've always thought that thermally isolating and insulating the array might 
be something worth trying.  This would lower the power consumption, and get 
rid of the problem some people have had of the heat affecting other components.

The only heated VCOs I have are a pair of SSM chips.  They do drift for 
quite a while before the temperature stabilizes.  The servo adds some noise 
to the output, which is another issue people don't talk about.


>The remaining problem is the max. frequency is around 1950 Hz, then it 
>latches until the CV is lowered. I had this problem the first time as 
>well, any ideas? BTW - I'm using a TL082.

Hmmm ... not really.  :-)

It's ramping up and not resetting?

   Ian 



From rdrake at data2action.com  Wed Apr 30 22:00:28 2008
From: rdrake at data2action.com (rdrake)
Date: Wed, 30 Apr 2008 16:00:28 -0400
Subject: =?US-ASCII?B?UkU6IFtzZGl5XSAxLXBvbGUgTFBGIHVzaW5nIGEgZGlmZmVyZW50aWFsIGludGVncmF0b3I/?=
Message-ID: <20080430200028.85309.qmail@mmm1113.verio-web.com>

how about that center-tapped pot on the output?  would love to see an alternative way of implementing that...

b

>----- ------- Original Message ------- -----
>From: lanterma at ece.gatech.edu
>To: synth-diy at dropmix.xs4all.nl
>Sent: Wed, 30 Apr 2008 01:08:32
>
>One project idea that I tossed out to my students,
>which one student  
>is trying to get work, is to use the idea of an NPN
>differential amp  
>driving a "differential integrator" to build a
>1-pole LPF, which you	
>could then do four times to get a usual 4-pole LPF.
>
>
>I got the idea from the EML-101 filter schematic,
>as expertly redrawn  
>by Marjan Urekar:
>
>http://members.tripod.com/urekarm/synth/eml101vcf.p
>df
>
>The EML-101 is a state variable filter, and said
>diff amp/diff	
>integrator configurations form the variable gain
>integrators.
>
>My thought was that we could take the output of
>such an integrator,  
>and feed it into the opposite input terminal of the
>diff pair, and  
>that feedback should form a 1-pole LPF, as follows:
>
>
>The NPN pair driving the differential integrator
>forms a variable gain	
>integrator with transfer function A/RCs, where A is
>the voltage gain  
>of the diff pair and R and C are the resistor
>values used in the  
>integrator. Let's denote wo = A/RC. Now imagine we
>take the output of  
>this integrator and feed it back into the input
>with a minus sign. You  
>get something like this:
>
>Y(s) = (wo/s) [X(s) - Y(s)]
>
>Y(s)[1 + wo/s] = (wo/s) X(s)
>
>Y(s)/X(s) = (wo/s) / (1+wo/s) = wo/(s+wo)
>
>Which is the transfer function of a single-pole LPF
>with cutoff wo  
>with unity gain at DC. (This is the same idea as a
>usual OTA-C filter  
>1-pole LPF).
>
>Three questions:
>
>1) I sent my student, Justin, this sketch to get
>him started:
>http://users.ece.gatech.edu/~lanterma/eml_inspired_
>vcf_sketch.jpg 
>, where I just blindly ganked the resistor and cap
>values from the EML  
>circuit.
>
>Anyway, I just realized I drew that wrong - the EML
>integrating stage  
>is _inverting_, so we should actually either:
>
>A) Swap the inputs on the differential integrator,
>to make a  
>noninverting stage, or
>
>B) Take the feedback to the left NPN instead of the
>right NPN
>
>Does (A) or (B) sound like the safer option?
>
>2) Given the way the "differential integrator" is
>going to load the  
>differential amp, should I even be thinking of this
>as a differential  
>amp followed by a differential integrator? Or are
>they interacting so  
>much such thinking breaks down?
>
>3) Does this whole crazy idea of mine sound like a
>decent idea at all  
>or is it doomed to insanity?
>
>- Aaron
>
>P.S. This got me wondering if there's an
>"integrating version" of the  
>standard 3-op-amp instrumentation amplifier? A
>differential integrator  
>with high input impedance, but something more
>elegant than just  
>slapping noninverting op amp buffers at the inputs
>to the above  
>differential integrator?
>
>http://en.wikipedia.org/wiki/Image:Opampinstrumenta
>tion.svg
>
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


From sounddoctorin at imt.net  Wed Apr 30 22:19:55 2008
From: sounddoctorin at imt.net (Bob Weigel)
Date: Wed, 30 Apr 2008 14:19:55 -0600
Subject: [sdiy] Schematics for Siel DK70 anyone?
Message-ID: <4818D46B.5080802@imt.net>

Mine took a dive for no apparent reason just trying to repair a key and 
get a panel switch to respond better.  Fer cryin out loud.  Non-stop 
irritation of late. -Bob


From neil.johnson97 at ntlworld.com  Wed Apr 30 22:42:33 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 30 Apr 2008 21:42:33 +0100
Subject: [sdiy] More on the AN299 VCO
In-Reply-To: <6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>
References: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@smtp.ntlworld.com>
	<6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>
Message-ID: <820337D3-E7A3-4D8C-AD9D-2E08C00D2B2D@ntlworld.com>


On 30 Apr 2008, at 19:55, Ian Fritz wrote:

> At 09:51 AM 4/30/2008, Neil Johnson wrote:
>
>
>> Apologies if this has already been discussed, but it seems to me  
>> that you have IC2A the wrong way round when compared to the  
>> schematic in AN-299.
>
>
> AN299 does not specify which transistor in the schematic is which  
> in the array!

No, but it _does_ specify where the emitter and collector go.  I  
guess I should have been clearer - in AN299 the collector goes to the  
reference voltage and the emitter goes to the integrating cap.  In  
flight's schematic the emitter and collector are reversed, i.e. "the  
wrong way round".

Neil
--
http://www.njohnson.co.uk





From neil.johnson97 at ntlworld.com  Wed Apr 30 22:44:28 2008
From: neil.johnson97 at ntlworld.com (Neil Johnson)
Date: Wed, 30 Apr 2008 21:44:28 +0100
Subject: [sdiy] More on the AN299 VCO
In-Reply-To: <6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>
References: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@smtp.ntlworld.com>
	<6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>
Message-ID: <312F35AB-326C-408C-8F23-3F661AE32D16@ntlworld.com>

(following up on my own email)

On 30 Apr 2008, at 19:55, Ian Fritz wrote:

> At 09:51 AM 4/30/2008, Neil Johnson wrote:
>
>
>> Apologies if this has already been discussed, but it seems to me  
>> that you have IC2A the wrong way round when compared to the  
>> schematic in AN-299.
>
>
> AN299 does not specify which transistor in the schematic is which  
> in the array!
>

I see the correction (swapped emitter/collector) has been made now.

Neil
--
http://www.njohnson.co.uk





From tshire at charter.net  Wed Apr 30 22:56:18 2008
From: tshire at charter.net (Travis Shire)
Date: Wed, 30 Apr 2008 16:56:18 -0400
Subject: [sdiy] Tube microphonics: 12SQ7GT & 12AV6, 6SN7GT & 6CG7/6FQ7,
	etc.
References: <007c01c8aa57$654eaa30$8501a8c0@ice9><018b01c8aa64$ba534510$0202a8c0@positronium><000b01c8aa74$479b2fa0$6401a8c0@cyberup0n1qn6z>
	<01a101c8aaeb$525137b0$0202a8c0@positronium>
Message-ID: <002401c8ab04$a6efee60$6401a8c0@cyberup0n1qn6z>


> I haven't been on Usenet in forever since before the web existed as such
> really. But I think the appeal that this group has still applies there I
> hope: you can almosty always depend on a few quick replies. Webpage-based
> forums not so much.
>
> Would I have to wade through a lot of audiophile prejudices on
> rec.audio.tubes? I guess it's not called
> rec.audio.tubes.direct-heated-cathodes-only...
>
> anthony
>
Just get at it through Google groups. Its more convenient than using a
newsreader since you can choose the threads you want to read.
http://groups.google.com/group/rec.audio.tubes/topics?hl=en&lnk=sg

Its not all 300B snobs in there....its a good place to discuss anything tube
related. Mostly home audio types, but there's a few that drop in to talk
guitar amp designs. Alt.guitar.amps is more geared toward guitar amps, but
its kind of been ruined by politics and spam....I still hang out there tho.

In this list I consider tube talk off topic because synths are not typically
associated with tubes. I know theres a few nutcases out there who build pure
tube synths, but still thats a drop in the bucket. You'll find more info in
the appropriate place.

Not try'n ta be a dick, just want to get you somewhere better to talk toobs.



From veronica.merryfield at shaw.ca  Wed Apr 30 23:08:36 2008
From: veronica.merryfield at shaw.ca (Veronica Merryfield)
Date: Wed, 30 Apr 2008 14:08:36 -0700
Subject: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)
In-Reply-To: <4818B303.20503@earthlink.net>
References: <00dd01c8a923$3bef09d0$0202a8c0@positronium>
	<215469.74040.qm@web63901.mail.re1.yahoo.com>
	<3de47a20804300808y5b9806dex22b8620e191df102@mail.gmail.com>
	<1DC627E6-E8EB-4CF1-B90F-2B8DC6039D9C@electricdruid.net>
	<9184C154-2D3A-4E88-8F63-86D0BEC97949@shaw.ca>
	<4818B303.20503@earthlink.net>
Message-ID: <DDF391A6-2B77-4904-B054-1C7A7E4D38EE@shaw.ca>


On 30-Apr-08, at 10:57 AM, Eric Brombaugh wrote:
> Veronica Merryfield wrote:
>
>> The way to make this work is not to have 12 dividers but to use a  
>> rolling scheduler.
>
> Very nice approach.
>
>> A little intelligence will be needed to handle events that come  
>> close together.
>
> You said a mouthful there. Traversing the queue to schedule the next  
> instance of the current edge, then fetching the top of the queue to  
> set the timer for the next event is probably going to eat up enough  
> time to make event crowding a very real issue. A fun problem for  
> someone. :)
Since the event set is limited, or perhaps I should say very well  
defined, and although I know there will be occasions where thing will  
get congested, I think it would work, The queue is a simpler problem  
than most queues, again it is limited and well defined, and I think  
there are a number of optimization opportunities.

Also, the description queue here does not mean a linked list. For  
instance, if the event structures had an extra field that is a next  
index, the events could be an array of structures and a single  
'next_index' variable. The rejigging of the queue is about changing  
the times, the next index fields and the next_index. At the times  
where it gets congested, the event edges might be off by a few clocks  
but that should be no real issue and could add to the character or  
effect :) If you wanted to ensure the errors didn't accumulate, you  
can correct for delayed events, again, that happens in ECUs.


From ijfritz at comcast.net  Wed Apr 30 23:17:42 2008
From: ijfritz at comcast.net (Ian Fritz)
Date: Wed, 30 Apr 2008 15:17:42 -0600
Subject: [sdiy] More on the AN299 VCO
In-Reply-To: <312F35AB-326C-408C-8F23-3F661AE32D16@ntlworld.com>
References: <20080430155715.YGGD26699.aamtaout03-winn.ispmail.ntl.com@smtp.ntlworld.com>
	<6.2.1.2.2.20080430125245.02236f28@mail.comcast.net>
	<312F35AB-326C-408C-8F23-3F661AE32D16@ntlworld.com>
Message-ID: <6.2.1.2.2.20080430151619.02179cf0@mail.comcast.net>

At 02:44 PM 4/30/2008, Neil Johnson wrote:

>I see the correction (swapped emitter/collector) has been made now.

:-)

OK, I was looking at the corrected version, so I thought you must have 
meant that A and B were reversed.

Ian 



