From the Blacet website:
VCA2200 Voltage Controlled Amplifier/Mixer
- State of the Art Quad Exponential VCA (100 mV/dB)
- Ultra Low Noise
- Ultra Low Distortion
- 100 dB/ 75 dB Range
- AC/DC Operation
- 0-10V CV Range with 0-5V Option
- Gain and Overdrive/Clipping
- Separate Voltage Control of any VCA or leave unconnected for unity gain mixer use
- Quad Mixer/VCA with optional voltage control of any channel. Linear Mix controls
- Triple Mixer/VCA with separate VCA for final VCA or other use
- Use any VCA for audio or control voltage processing.
- Pan/Fade with external normal and inverted CVs.
Download Blacet’s QUAD VCA BASIC MANUAL.
Modifications:
- Front-Panel-Express MOTM style panel
- Circuit modified to become two separate 2-into-1 VC mixers
- 0 to +5V control range.
- CV connection to control all four (ABCD) two each (AB, CD) or individual (A, B, C, D) channels with one CV.