I'm working on my first circuit which includes LM386 chip and some music. Since I don't have a lot of experience with electronics I need a little help with audio plug. It's the same as that:

Audio Plug

I know that number 1 on the audio plug is GND. The biggest problem I have is that I don't know how to correctly connect other four pins to my input on LM386. As I read, this audio jack is stereo, but LM386 is mono. I followed this tutorial and I would like to somehow connect this audio jack to 10K potentiometer. Here's schematics of my current circuit:

enter image description here

What should I do now - how to connect this audio jack to my LM386's input?

up vote 5 down vote accepted

If you want both the left and right channels to provide audio you need to make a little mixer.

Two resistors (around 10KΩ) connected to the left and right inputs (pins 2 and 5), then joined together, will make a simple mixer. Then you link that to the LM386's IN + through a capacitor (around 10µF is usually OK).

Pin 1 links direct to the IN -

You ignore pins 3 and 4 - they are used to pass the audio through to another destination (internal speakers) when there is no plug in the socket.


simulate this circuit – Schematic created using CircuitLab

  • 10uF capacitor must be ceramic? – user1257255 Jul 11 '14 at 6:23

Usually the tip is the right channel, the ring is the left channel, and the sleeve is ground. Therefore on your diagram, 1 is the (-) input, 2 is the (+) if you want to use the left channel, 5 is the (+) if you want to use the right channel. Pins 3 and 4 are connected to 2 and 5 when there is nothing connected and disconnected when something is plugged in, which can be used for example to detect whether something has been plugged in or not.

Of course you have to decide which channel of the original source to use, since as you said, the LM386 is mono.

This will minimize "pops" on plug-in, and will keep the amp quiet when nothing's plugged into it:

enter image description here

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