[SOLVED] Audio - Stereo & mono to stereo output issue

[BrownSubmarine]

I am connecting a stereo signal and a mono signal to the same stereo output.
So the issue is... the stereo signal runs down the wire, then up the mono wire combining the left and right channels turning my stereo signal into mono.
I want the mono to play mono sound to the output and the stereo to play stereo sound to the output... how do I do this?
I thought maybe using diodes, but that might lower the volume/quality?

 

[Audioguru]

You should NEVER short outputs together unless they are designed to be shorted together.
Diodes will cause SEVERE distortion if the signal level is high enough for them to rectify the signal.

You need to use an audio mixer circuit.

 

[BrownSubmarine]

Thank you.
I should also state that the Audio inputs will not be played at the same time.
Do you have an example of an audio mixer circuit that would be applicable to my situation?

 

[Audioguru]

If you feed the signal of one product into the output of another product then damage to both circuits can occur if they are powered or not.
An audio mixer circuit keeps the outputs completely separate but allows any signal to go through to its output without attenuation.

An inverting audio opamp is usually used as an audio mixer circuit. You need two circuits for stereo.
Here is a circuit that uses a dual opamp for stereo:

 

[BrownSubmarine]

Wow. Thank you for the good example and explanation. I'll give this circuit a go. I'm off to the local electronics store.