I have a circuit board I took from a broken wireless headset, and I plan of reusing it by soldering a 3.5mm plug to where the speakers was connected. So I could plugin whatever headset I want. But today I noticed that the circuit board have 4 pole/pins. L- L+ R- R+ while the plug only have R+ L+ and ground. Can I simply take R- and L- and solder them both to ground, or do I need a components to combined them first?
Normally I just trial an error, but since I only have one board I don't want to damage it by doing something dumb.