Important: If you follow my procedure I accept no responsibility for any damage you do to yourself, your phone or your headphones. I have carried out this hack and can confirm that it works perfectly with the Orange SPV M3100. It should work equally well with the HTC TyTN (and other HTC Hermes variants), Orange SPV C100 (HTC Oxygen), and the Orange SPV C700 (HTC Breeze).
You will need a 3.5mm Stereo Jack Socket and a Soldering Iron to carry out this hack.
First thing I did was cut the USB connector off the standard Orange headphones about 75mm from the USB plug itself. I decided that I wanted a short headphone adapter as my headphones have a long cable of their own.
Next strip back about 15mm of the cable sheath. Do this carefully so that you don’t damage any of the wires inside, the wires inside are very thin and only insulated with coloured varnish.
Now we need to carefully separate the wires. We need the following colours:
Twist the Left and Right Ground wires together and tin the ends of the 3 cables that we are going to use. You can cut the other wires short - we don’t need them as they are used for USB data
What needs to be done now is to solder the wires to the 3.5mm Jack Socket that we have. Don’t forget that the socket cover goes over the cable before you solder the wires on! The connectors that your socket has may differ from mine. However, as a rule of thumb, jack sockets (and plugs for that matter) tend to have a silver and a copper solder tag for the positive left and right connectors. The right side is almost always the copper one. Solder the red wire to the right side, the green to the left side and the two striped cables that we twisted together to the outer ground of the socket.
Most jack sockets have a method of securing the cable in place. Mine had two metal clips that you bend down and use the clamp the cable
Now screw on the socket cover (you did put this on the cable before you soldered the connectors didn’t you!?) and then lets check the headphone adapter to make sure it’s working. If you have any problems then review your soldering and try again. All done!
I was surprised how loud the sound from the SPV M3100 was with my decent headphones!
Once again anyone carrying out this headphone adapter hack does so at their own risk but I’m happy to answer questions!
Original source: http://www.tracyandmatt.co.uk