This build uses stereo potentiometers and stereo TRS audio jacks to accommodate both mono and stereo devices.

The potentiometers and audio jacks are panel mounted in a 3D printed case.

The lid has cut outs for the potentiometers and audio jacks to mount to.

The lid also has indented text on the front to label the potentiometer and audio jacks. You can program in a filament swap to your slicer so that the text stands out.

The lid and main body are designed to snap fit together, making it possible to open and close as needed without any additional hardware.

First, you will connect each pot's stereo ground signals together.

Cut and splice five pieces of solid core wire. Each piece should be approximately 15 mm long.

Bend the wire into a U shape. Bend the spliced ends so that they are sticking out at a 90 degree angle from the U shape bend.

Insert the wire into the potentiometer's two ground pins.

Solder the wire to the potentiometer's two ground pins.

Repeat for the remaining four potentiometers.

Insert a potentiometer into the first larger hole on the front panel of the 3D printed case. Secure it with the included nut.

Mount the remaining four potentiometers.

Insert an audio jack into the first smaller hole on the front panel of the 3D printed case. Secure it with the included nut.

Mount the remaining four audio jacks.

The stereo audio jacks have three pins. The longest pin in the middle is wired to ground and the two shorter pins are wired to the left and right audio signals.

Cut, splice and tin five pieces of stranded core wire that are approximately 35 mm in length.

Solder the first audio jack's ground pin to the first potentiometer's ground pin.

Solder the remaining four audio jacks' ground pins to their corresponding potentiometer's ground pin.

Cut, splice and tin four pieces of stranded core wire approximately 40 mm in length.

Solder the wire from the first audio jack's left channel input (marked 3 on the jack) to the first potentiometer's front wiper (middle) pin.

Solder the remaining three input jacks' left channels to their corresponding potentiometer's front wiper pin.

Cut, splice and tin four pieces of stranded core wire approximately 35 mm in length.

Solder the wire from the first audio jack's right channel input (marked 2 on the jack) to the first potentiometer's back wiper (middle) pin.

Solder the remaining three input jacks' right channels to their corresponding potentiometer's back wiper pin.

Cut, splice and tin two pieces of stranded core wire; one approximately 35 mm in length and one approximately 40 mm in length.

Solder the longer wire from the output jack's left channel pin (marked 3 on the jack) to the output potentiometer's back output pin.

Solder the shorter wire from the output jack's right channel pin (marked 2 on the jack) to the output potentiometer's front output pin.

Cut, splice and tin four pieces of stranded core wire, approximately 90 mm in length.

Solder a wire to each of the four input potentiometer's front output pins.

Solder the other ends of the four wires to a shared row on the perma-proto board. These are the left channel outputs.

Cut, splice and tin four pieces of stranded core wire, approximately 85 mm in length.

Solder a wire to each of the four input potentiometer's back output pins.

Solder the other ends of the four wires to a shared row on the perma-proto board. These are the right channel outputs.

Solder a 1K ohm resistor to each of the shared rows on the perma-proto board.

Cut, splice and tin two pieces of stranded core wire; one approximately 85 mm in length and one approximately 90 mm in length.

Solder the shorter wire to the resistor connected to the right channel outputs. Solder the longer wire to the resistor connected to the left channel outputs.

Solder the right channel output wire to the main output potentiometer's back wiper pin.

Solder the left channel output wire to the main output potentiometer's front wiper pin.

Insert two M3 screws into the two holes at the bottom of the mixer enclosure.

Attach two M3 stand-offs to the M3 screws.

Align the perma-proto board's mounting holes on top of the M3 stand-offs. Secure the perma-proto board with two M3 nuts.

Close the mixer enclosure by snapping the lid onto the main enclosure. Now you're ready to get mixing!

First, plug in your audio sources. You can use up to four and any device can be plugged in as long as it had a standard line level output.

Then plug your output into a speaker or other gain stage.