This module is a 4 channel panning mixer that provides stereo outputs for your modular system. It has synth level outputs for the L/R channels and a headphone output. It can be built for both +/-12V or +/-15V systems without any modification and two boards can be combined to create an 8 channel module. 

CONTROLS
1.- 4. Input Level (1 per input) – These knobs attenuate the input signals.
5- 8. Pan (1 per input) – These knobs determine how far to the left or right the signal appears in the headphones
9. Headphone volume – This attenuates the mixed signal before being fed to the headphones.
INPUTS 1-4. Signal input – The audio to be mixed is input here. These inputs are DC coupled.
OUTPUTS 1. Headphone Out – This is a stereo output for use with headphones. It is AC coupled. 2-3. L/R Outs – These are DC coupled mono outputs for the Left and Right channels.