Eurorack/BIPO2

8hp Dual Bipolar VCA

BIPO (short for bipolar VCA) is a dual VCA and dual ring modulator (four quadrant multiplier). The VCA outputs are mixed together, so this module can acts as a 2 channel mixer or as a crossfader. This module serves as my general purpose VCA and as a replacement for my old crossfader module.

The four quadrant multiplication is achieved by taking an attenuverter topology and replacing the potentiometer with a VCA. The VCA needs to be biased in such a way that the amplitude of the VCA output is half of the input signal at 0V. The benefit of this topology is getting two outputs simultaneously