erica-synths/black-polivoks-vcf-v2

Black Polivoks VCF V2

Authentic sounding emulation of the famous Russian Formanta Radio Factory Polivoks VCF, using original Russian K140UD12 ICs in the sound circuit. Features independently buffered inputs, extended Cutoff knob, switchable BP/LP filter modes, and an output stage to eliminate signal inversion.328

Visualization filter_response

Capabilities 2

Self-Oscillationself-oscillation: Soviet-Polivoks-derived design with characteristic shrieking self-oscillation at high resonance.328
Vcfvcf: Authentic Polivoks VCF emulation using original K140UD12 ICs, switchable LP (12dB/oct) and BP (6dB/oct) modes.328

Jacks 4 — 3 in / 1 out

Name	Signal	Voltage	Description
Inputs (3)
CV1	cv	-10V to 10V	First cutoff CV input. Voltage applied here modulates the filter cutoff frequency, scaled by the CV1 LEVEL attenuator knob. Product-page spec: "CV input level -10V - +10V".328
CV2	cv	-10V to 10V	Second cutoff CV input. Independent of CV1 — both sum into the cutoff control voltage, each scaled by its own attenuator. Product-page spec: "CV input level -10V - +10V".328
INPUT	audio	-10V to 10V	Audio signal input. Buffered. Product-page spec: "Input level up to 20Vptp" (±10V peak). Level into the filter is scaled by the IN LEVEL knob.328
Outputs (1)
OUT	audio	—	Filtered audio output. The VCF response (BP 6dB/oct or LP 12dB/oct, selected by the BP/LP switch) is applied to the audio at INPUT. V2 added an output stage that eliminates the signal inversion of earlier revisions.328

Parameters 6

Name	Type	Range	Behavior
BP/LP	switch	—	Two-position toggle selecting filter mode. BP = bandpass 6dB/oct, LP = lowpass 12dB/oct. V2 eliminated the audible clicks the original revision produced when switching modes.328
Cutoff	knob	—	Sets the filter cutoff frequency manually. The "extended Cutoff knob" mentioned on the product page is the largest control on the panel — wider sweep range than the original Polivoks. Summed with the CV1 + CV2 inputs (each scaled by its own attenuator).328
CV1 LEVEL	knob	0% – 100%	Attenuator for the CV1 cutoff CV input. 0 = CV1 has no effect on cutoff; 100% = full CV1 scaling. Summed with the CV2 path and the Cutoff knob.328
CV2 LEVEL	knob	0% – 100%	Attenuator for the CV2 cutoff CV input. 0 = CV2 has no effect on cutoff; 100% = full CV2 scaling. Independent of CV1 LEVEL — both paths sum into the cutoff control voltage.328
IN LEVEL	knob	0% – 100%	Attenuates the signal at the INPUT jack before it enters the filter. Driving this knob into clipping is a Polivoks tone trick — the rare K140UD12 opamps generate distinctive saturation when overdriven.328
Resonance	knob	—	Sets the filter resonance manually. The Polivoks character — aggressive, throaty resonance — comes from the Russian K140UD12 opamps; at high settings the filter self-oscillates and can be played as a sine oscillator.328

Firmware history 0 versions

No firmware history recorded.

References 1

[328]
Erica Synths Black Polivoks VCF V2 product pageproduct_page
source 328 canonical ↗ archived ↗

⚠ verified 2026-05-14 · manufacturer changed since last verified