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Subject: CGS Tube VCA in MOTM format

From: Mark <yahoogroups@...>
Date: 2008-06-14

I recently built a CGS65 tube VCA in MOTM format using a panel and
bracket from Bridechamber. The version I built was heavily modified
from the original in order to reduce noise and improve the CV
response. I'm quite happy with it :)

Even though it is tube, it runs off the +15/-15V rails. By using a
miniature Russian "pencil" tube that is about the size of a pen cap,
the module doesn't require a separate power supply or draw an
excessive amount of current.

It is a very versatile and unique module. Nothing else sounds like
it. The amount of distortion is dependent not upon the level, but
the rate of change of the CV input. I don't know of any other device
that does that. You can also get different sounds by sending audio
to both the CV and audio inputs.


Here is a description of the original circuit:

http://www.cgs.synth.net/modules/cgs65_vca.html

Here is a description of my modifications:

http://electro-music.com/forum/topic-26469.html



Bridechamber sells the assembled module (although not with my mods
:), a full kit (only $75!!), the panel, bracket, and the tube:

http://bridechamber.com/bridechamber.com/C%20Tube%20VCA.html

If he is out of tubes, I bought extra, or you can find them on that
auction site. You can get the PCB from Ken Stone.

It's a rather simple circuit, with only two dual op-amps and one
tube, that only takes about an hour or so to build. So it's an easy
and inexpensive way to add tube synthesis to your modular, without
having to buy a noisy overpriced piece of crap covered in pornography
:)



While I'm typing, here are a couple of things I have for sale:

Morley Rotating Wah http://telrayoilcanaddicts.yuku.com/topic/661

Garfield Doctor Click http://electro-music.com/forum/topic-26991.html