Serge/cgs108 gain cell vca

[ketem13]

Is there anywhere I could find the gain cell vca schematics?
I could not find it anywhere.
Any reason for that?

Thanks in advanced.

[lemberski]

Look here:
http://www.deliandiver.com/designs/serge-gain-cell

and here for a short explanation how it works:

[pugix]

Look here:
http://www.deliandiver.com/designs/serge-gain-cell

I downloaded the schematic from there. Never saw that before, although I drew it for myself at the time I built Ken Stone's Serge VCFQ.

https://pugix.com/synth/serge-vcfq-and- ... e-shapers/

Click the Serge Gain Cell link on my page above to get Ken's description of the gain cell, where he stated, "The circuit is proprietary, and I do not have permission to share the schematic."

I have drawn or received a lot of proprietary schematics, but I don't publish them.

[pugix]

Wow, that Youtube channel is a great resource!

[loki]

This is one of the bits of synthesizer circuit design history that is continually misrepresented. The "Serge gain cell" was patented first in a diode version by Thomas Stockham and Alan Oppenheim filed in 1967, see US patent 3,518,578. A patent covering a compression/expansion system. It was then patented in transistor form, filed in 1971, by David Blackmer. US patent 3,714,462 Since it was published by the US patent office and the patents are now expired, it is nonsense for Ken Stone to claim it is proprietary.

[cygmu]

This reminded me to retrieve those patents which I think loki has mentioned before. While I was doing that I thought I might as well post the links here for others, to save them the nine clicks it took me.

Oppenheim and Stockham: https://patents.google.com/patent/US3518578A/
Blackmer: https://patents.google.com/patent/US3714462A/

[Rob Kam]

I read it not so much that Ken Stone claims the patents are proprietary as that at the time he posted that page to the web Serge Tcherepnin had not consented to having the schematic published.