DIY Polivoks-inspired VCA

Dual VCA based on K118UD1 differential opamps

The Polivoks VCA has distinctive architecture – two differential opamp (Russian ICs K118UD1B) based VCAs in series each for LFO and ADSR control over signal amplitude independently. Control voltage to attenuation behavior of this VCA is nonlinear and not logarithmic. It is kept authentic to the response of original Polivoks. Most parts of the VCA have been improved to achieve compatibility with eurorack signal and CV standards, higher dynamic range, better reliability, lower noise, accept higher signal levels, keep consistent behaviour, self-tuning of two internal offsets and higher linearity, though the heart of it is kept the same. Also we redesigned audio signal path, so that you can use it as two independent VCAs or two VCAs in series as in original Polivoks, plus summed signal output.
FEATURES:
Single or Dual VCA mode
CV level adjustment for each VCA
Summed audio output (lower signal gain, though)
Skiff-friendly design

http://ericasynths.lv/en/shop/diy/diy-kits-1/diy-polivoks-vca-2/