Modstar AMP

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ﾗ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ﾗthe overdrive circuit from the Boomstar desktopﾗ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.

All Controls & Patch Points
INPUT ﾖ Adjusts the audio input.
STAGE 1/2 ﾖ Adjusts stage 1/2.
STAGE 2/2 ﾖ Adjusts stage 2/2.
DRONE ﾖ Sustains the last note receivedﾗﾓHold that Train.ﾔ
DRIVE ﾖ Final output stage overdirve/saturation.
OUTPUT ﾖ Adjusts the audio output.
INPUT ﾖ Audio input.
ST 1/1 ﾖ Stage 1/1 input.
ST 1/2 ﾖ Stage 1/2 input.
ST 2/1 ﾖ Stage 2/1 input.
ST 2/2 ﾖ Stage 2/2 input.
OUTPUT ﾖ Audio output.

* From 7:00 (0) to 9:00 our ﾓNegative Resonance Saturationﾔ adds beefiness, boosting the waveform amplitude and taming waveform transients; set to 9:00 to achieve the cleanest tone possible.