Studio Electronics Boomstar VCA Eurorack Module
The amplifier (AMP) is a 2 stage Class A discrete design using 3 pairs of hand matched transistors. Envelope is usually applied to ST1/1. ST1/2 goes thru an attenuverter and can be used for envelope or modulation. ST2/1 goes to the 2nd stage, and is typically used for volume control. ST2/2 goes thru an attenuverter and is typically used for modulation.
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. Like our filters Boomstar Modular AMPs are hand-built entirely in the U. S. of A—just ask Rachael Herbison!
Potentiometer Potential - Four attenuation pots control the INPUT, STAGE 1/2, STAGE 2/2, 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, and bite.
Patch it Up - Six patch points: INPUT, ST 1/1, ST 1/2, ST 2/1, ST 2/2, OUTPUT direct the deepest manipulation.