The Modstar VCA Amp is a Class A discrete amplifier module and provides an essential element to your modular setup. Featuring 3 pairs of hand matched transistors and a 2 stage design, with this VCA you can control the volume in two ways/stages at once. This flexible design can be used be used for envelope, modulation and volume control and has a warmth to its sound that is not clinical. The Modstar VCA Amp has serious character!
The AMP, the 5089, and the 3003 are Class A circuits. They draw more current from the +12 rail than from the -12 volt rail. If the system power supply is under-sized, hum or buzz may be heard. In that case, larger filter capacitors and/or a larger power transformer will be needed. The 4075 draws equally from both rails, and is more immune to hum.
Two attenuverters and two attenuation pots control the INPUT, ST1 CV2, ST2 CV2, and OUTPUT, delivering smooth, detailed, and complex expression.
Switch it Up
Uber useful continuous hypnotic DRONE for endless sustain/release, and DRIVE—the overdrive circuit from the Boomstar desktop—for last stage energy, bite, soft clipping, and gonzo '70's era "Distortion +" crunchy fuzz.
Patch it Up
Six patch points: INPUT, ST1 CV1, ST1 CV2, ST2 CV1, ST2 CV2, OUTPUT direct the deepest manipulation.
All Controls and Patch Points
INPUT – Adjusts the audio input.
ST1 CV2 – Adjusts stage 1, control voltage 2.
ST2 CV2 – Adjusts stage 2, control voltage 2.
DRONE – Sustains the last note received.
DRIVE – Final output stage overdirve/saturation.
OUTPUT – Adjusts the audio output.
INPUT – Audio input.
ST1 CV1 – Stage 1, control voltage 1 input.
ST1 CV2 – Stage 1, control voltage 2 input.
ST2 CV1 - Stage 2, control voltage 1 input.
ST2 CV2 – Stage 2, control voltage 2 input.
OUTPUT – Audio output.
Size - 8hp
Depth - 39.7mm with ribbon cable attached
Power Usage - 36mA, 12mA (+12 / -12)