Originally Posted by
Keygrip
I'm told that the problem may be something to do with the impedance of the two units and that the pda "pulls down" the mp3 - which I believe but find confusing if they both work through the same cheapie headset.
They may work through the same headset, but that is one at a time, if the impedance of each unit is the same, when connected together (in parallel) the impedance will be approximately halved, and may cause problems.
What would be needed is a small impedance matching circuit, so that all should be ok.
Maybe MAPLIN or RS would have the bits and circuit details required.