Quad Discrete VC Equalizer / Resonator

Four parametric bandpass filters with full voltage control connected in parallel.
Two main modes selectable by switch - Equalizer (when input signal is presented at the output), and Resonator (when input signal is not presented at the output).
Switchable to low-shelf on first channel, and to hi-shelf on fourth channel.
Switchable to selfoscillation mode via DIP-switches. For v/oct trimming.
Bypass switch.
Input level attenuator and overload LED help to avoid clipping.
Bipolar level control. +-16dB, CV range +-5V.
Bandwidth control 0.5...24 semitones. CV range +-5V.
Frequency control 10 octaves. CV range 0...10V.

http://l-1.su/DiscreteEQ.html