Erica Synths - Black Polivoks VCF

Very authentic emulation of the voltage controlled low-/bandpass filter from the russian Formanta Polivoks synthesizer. Although the circuitry was adapted to modern modular systems and the low-end's behaviour was enhanced, the module's heart still are the original intedrated circuits K140UD12 responsible for the filter's special sound with it's wicked resonance.

The Black Polivoks Filter has two modes: a -6dB/octave steep band pass and a -12dB/octave lowpass, between which you can select with a click-less switch. Soundwise we'd call this filter "wet" and very specific. It has resonance wich starts oscillation at maximal fully clockwise position. The oscillation is pretty unstable which is charming.
The Polivoks' trademark sound of course depends on the input level, for which reason you have a level control.

There are two voltage control inputs for modulating the cutoff frequency. They are buffered to eliminate interference between them.