Simple audio mixer


I have one low cost TPA3116 amplifier which has got more usage than I initially thought. I ended up using it in the living room, it provides enough power and burns only 0.7W from the mains while ON, with no signal. So low that I don’t need to worry about shutting it down when there is no signal, so it’s on all the time. So on to the problem: I need to use it with 2 sources and having an additional one for the fellow guests to plug in the phone is useful.


While the idea of a multi source automatic selector has crossed my mind, I found a better solution: mixing. Since all sources have their own digital volume control, I don’t need individual, analog, volume control. So I added 2 more stereo inputs.

Note: there will be signal attenuation, however this still gives me ample output power for my needs. I pretty much leave this thing on max and just use the digital controls.

Opened the case up and drilled 2 extra holes

Disconnected the original signal lines

Add three resistors for each input. 6.5 K ought to do it..they were right there on the table.

Connect the initial RCA jacks to one set of inputs

And as you can see there is room for not one Jack, but 2 extra Jacks 🙂

Make connections, also use shrink tube

All complete

You can even grab one on through affiliate links which helps me support this website, while offering you the same low price (Disclaimer!).


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  1. Pingback: Technology I want – Electro Bob

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