Forgot to mention this:
The circuit can run on either +/-15V, or +/-12V, or be self-supplied with a small transformer or AC wallwart.
So apart from using it in the usual modular systems, it would also make a nice pedal or tabletop unit.
In addition to the EMS original function, there will be an "Initial Gain" pot for the VCO, so you can run your signal thru the VCA circuit just for coloration, but with permanent gain, and then gradually blend in the modulation.
I guess I have to make some demo mp3's playing my Farfisa organ thru this. :)
JH.
----- Original Message -----
Sent: Sunday, July 25, 2010 7:16 PM
Subject: Interested in Trapezoid VCA PCB?
I wonder how many interest there would be in a PCB for a Trapezoid VCA.
It would - of course - be designed to emulate the behaviour of the famous EMS Synthi A and VCS3 Trapezoid, and it would be - of course - not be a direct copy of the EMS circuit.
Usual pricing for my PCBs, no exotic components needed, rather easy to build, no component selection necessary.
Let me know.
JH.