This is a eurorack 4 channel attenuvertor with unity buffer or 3x or 10x gain pre-amp.
The board is 100mm high, 33 mm deep with the power header protruding a bit further. It should be 2HP wide.
This is totally untested, based purely on the circuit in Walter Jung's "IC Op Amp CookBook".
Will be testing soon, before getting the board made up.
Eurorack modular synthesizers use IDC connectors to distribute power. They are 16 pin 2x8 male headers, or 10 pin 2x5. In each case, there are two columns of pins, #1 on the right, with 3, 5, 7, ... above it, and 2, 4, 6, 8, ... on the left.
Pins 1 & 2 are shorted together to supply -12V; pins 3, 4, 5, 6, 7, 8 supply GND; pins 9 & 10 provide +12V. Some companies only use these 10 connectors. On...
A simple AR design using op amps, inspired by Nathan Ramsden. [https://synthnerd.wordpress.com/2016/04/06/envelope-circuits-a-simple-ar-design-using-op-amps/](https://synthnerd.wordpress.com/2016/04/06/envelope-circuits-a-simple-ar-design-using-op-amps/)