Not much info on this one, but basically it was a compressor made by Univox in the 70’s as part of their “foot” series. Seems to be loved by many and was recently requested. In addition to the schematic posted in the request section I found another schematic posted over at FSB, so I made 2 different layouts.
One thing to note is that the original didn’t use an LED & LDR, but used a Vactrol labeled MCD527. I’m not quite sure what color LED and LDR range you should use. I would start with try a red LED and socket the LDR and try different ones to get a good range. If you were to try a vactrol maybe a NSL32 or VTL5C3 which have bee used on many different optical compressors.
Don’t forget if you’re using an LED & LDR to cover them in shrink wrap to block out any light and increase their efficiency and effect.
Layout 1: Based on the Schematic in the Request Section
Layout 2: Based on the Trace ad FSB of a Uni-Comp Model CO-105
