The stereo audio jack's three pins are numbered on the bottom of the jack. GND is connected to pin 1 and is the longest pin in the middle of the jack. Right channel audio is connected to pin 2 and left channel audio is connected to pin 3.
The passive mixer circuit consists of four identical audio inputs and one audio output. All GND connections are connected together.
Audio Input Wiring
- Audio jack GND (pin 1) to potentiometer GND
- Audio jack right channel (pin 2) to potentiometer wiper (front)
- Audio jack left channel (pin 3) to potentiometer wiper (back)
Potentiometer Output Wiring
The output signal from each audio jack input is wired to shared row on a perma-proto board so that they can be sent as one signal to the main output.
- Potentiometer front output to perma-proto board row 10
- Potentiometer back output to perma-proto board row 13
- Potentiometer GND to perma-proto board GND row
The shared left and right audio signals are wired to the main output potentiometer's wiper pin.
- Perma-proto board row 13 to main output potentiometer wiper (front)
- Perma-proto board row 10 to main output potentiometer wiper (back)
- Perma-proto board GND row to main output potentiometer GND
Audio Output Wiring
The main output signal is wired to the main output jack with a 1K ohm resistor on each channel.
- Potentiometer front output to 1K ohm resistor to audio jack right channel (pin 2)
- Potentiometer back output to 1K ohm resistor to audio jack left channel (pin 3)
- Potentiometer GND to audio jack GND (pin 1)
