Chuck D. Bones
Circuit Wizard
I had been meaning to breadboard this for a long time, even before PedalPCB started making boards. It's a very clever and well-explained design by Valve Wizard. My first compressor was OTA-based: the Electro-Harmonix Black Finger. It used the same design trick of putting the OTA in the feedback loop as the Engineer's Thumb. Once I've spent a little more time refining it, I'll share the schematic. It's very close to the Engineer's Thumb v4. The main difference is I put in a pot to control the brightness instead of a switch.
Controls, L-R: LEVEL - BRITE - RATIO - RELEASE - ATTACK - THRESHOLD
The 3mm red LED at the bottom, next to the EZ-hook, is the compression indicator. The two grey LEDs just to the left of the green power-on indicator are the input clippers.
Controls, L-R: LEVEL - BRITE - RATIO - RELEASE - ATTACK - THRESHOLD
The 3mm red LED at the bottom, next to the EZ-hook, is the compression indicator. The two grey LEDs just to the left of the green power-on indicator are the input clippers.