Four multi-function VCA channels

Separate positive and negative control voltages; sum, difference, and global sum outputs. Patch programmable as four separate two-quadrant VCAs; two four-quadrant ("ring modulator") VCAs; mid/side encoder and decoder; voltage controlled pan; crossfade; and various combinations. Offset knob on each channel can be set a little below zero to help solve "bleed" issues. Accurate unity gain at +5V unattenuated control input, above-unity gain available with higher control voltages.

https://northcoastsynthesis.com/products/msk-015-quad-vca.html