DIY Passive Audio Mixer




About: High School Maker

I have wanted to make an audio mixer for a long time now, but I couldn't find one that would get two channels from one audio jack, so I made one! This mixer is passive, meaning it doesn't need power and it can be configured in Virtual DJ as an external mixer with a stereo to mono splitter. This is my first instructable, I don't usually make such guides but I thought I would give it a shot. If you make this project, be sure to share pictures because I want to see how you made it!

If you liked my instructable be sure to vote for it!

Step 1: Gather Required Components

To make this audio mixer, you will need:

2x 10k Potentiometers

2x 1k Resistors

2x Momentary switches or pushbuttons (the pic has only one because the other was being used)

2x TRS 3.5 mm audio jacks (you can find these in old mp3 players).

Several female to male and male to male wires

1x Breadboard

Step 2: Wire Up the Components.

Now we can wire up the components on the breadboard. You can use momentary switches instead of buttons if you would like to.

Step 3: Fit Into an Appropriate Casing and Style.

Now that all the electrical parts are done, we can find a casing for the components and make it all look good, maybe even give yourself a DJ name. ;) I have attached the graphic I made and used so you can change it to fit your casing.

Note: I blurred out my DJ name because it is very original and unused and I spent a very long time coming up with it.

Step 4: Get Mixing!

Feel free to add leds and other creative aspects, the only reason I didn't is because I wanted my mixer fully passive. Go and mix some tunes!

UPDATE: I ended up adding two blue LEDs at the bottom that will blink to the music. The schematic and pics/vid of that is in the next step.

Step 5: Add Sound Reactive LEDs (Optional)

Adding sound reactive LEDs is optional as it will make your mixer active (meaning it will require power). Pictures of the components required and the schematic are above. I also attached a video of the finished project above.

The updated schematic is also above.


1x TIP31 Transistor

1x Power Supply Module

1x 9V 1A Power Supply

2x Blue (or any color) LEDs



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    4 Discussions


    2 years ago

    Breadboards are fpr prototyping not for the final use. you need to go get a pc board and solder everything. you can get one at Radio Shack(2760150) or order one from Jameco(2125042),Digi-key, or others. If you don't it will eventually fail and if you are using it for a gig, it will probably fail during a show.

    1 reply

    Reply 2 years ago

    Thanks for the suggestion, however I simply created it with a breadboard for demonstration purposes, and I have already disassembled it. Also, if I were to create this as a final product I wouldn't use cardboard and I would purchase matching potentiometers.


    2 years ago

    Do you mix left and right channel of a stereo source to a mono output ?

    1 reply

    Reply 2 years ago

    The mixer mixes left and right of a stereo source out to a stereo output, or it can be configured to output to a mono output.