[ve3hbj]

Hi all. I'm new here but not so new to electronics. I'm interested in taking two audio sources eg a two way radio feed from work and my iPod streaming music and combine them to one feed and listen on headphones.

I think it's doable using a simple resistor based mixer but I'm concerned about audio level drop so I was then thinking of adding an amp either an upgraded COmy or other easily diy'd amp to fit into a mint box or altoids can. But I don't know if the two circuits would react with each other or cause other problems. In my head it seems ok.
Has any one done this or have any suggestions. My two thoughts are to use something in the 1-10k range for my mixer circuit. I'd run the two inputs in parallel with matched resistors on each side or use dp trimmers on each input so I can fine tune the mix before it gets to the amp. (This can be accomplished at the sources with their volume controls easier and cheaper I suspect)

The other option as I have a nice set of Bluetooth headphones would be to mix them then transmit via Bluetooth but I suspect this would be far more expensive.
Thanks any thoughts would be great?

 

[FallenAngel]

http://www.beavisaudio.com/techpages/blocksfragments/Passive_Mixer.jpg - Something like that should work, of course make it 2 channel, and I'd lower those resistor & pot values to something reasonable - maybe 50K pot and 4k7 resistor, or a 10K pot and a 1K resistor.

 

[ve3hbj]

Thanks for your suggestion. What do you think would be the effect of removing the pots all together obviously I'd lose the ability to adjust the input volume/balance locally and would have to do it at the source. Is there something electrically I'm missing by doing that.