Hi, I have several audio sources (radios) and one stereo source (computer). I could not find a basic stereo mixer so bought parts to build one including a small "headphone amplifier" to boost the signal back up since each source will pass through resistors to prevent them from interfering each other (this is from a passive mixer design found all over the net). http://www.instructables.com/id/Altoids ... reo-Mixer/
I plan to have a toggle switch for each left and right channel even though most sources are mono. That way I can feed one radio to my left ear and another to the right to compare signals.
The issue I need answered is that I need to keep the stereo source isolated, so it stays stereo even if both channels of a mono source are fed to both headphone sides. It seems to me that when a mono source is switched to feed both sides, then my headphones will become mono through that source and the stereo will mix to mono.
Is there a way, such as with diodes or some method to allow mono source to push to both headphone sides while the stereo source does the same only doesnt tie together back before the l/r switches for that mono source.
This is only an issue when a mono source has both l/r switches closed typing both headphone sides back together.
Hopefully I've made the problem clear enough!