4 OTA-based VCAs + Mixer output

This module is 4 VCAs in an 8HP package. The VCAs are fairly straight forward OTA based designs, pretty close to the Polyfusion VCA and just about every VCA from the 70's. The CV is switchable between linear and exponential, and there is a mix out at the bottom so it can be a 4-channel CV controllable mixer.