[GREQ]

I documented a detachable cable mod on the Sony MDR-CD900ST for @digitalreferee

The goals for this mod:
• Looks good
• Minimal destruction
• Single-sided stereo socket
• Reterminate original cable with 3.5mm plug

End of reterminated cable mod is not included because there are enough retermination tutorials already.

	Prepped and ready
	Open the headphone: Notes: Do not worry about the screws falling into the driver - the screw heads are bigger than the acoustic-lens holes, so there is no risk of them entering and damaging the driver
	Unsolder all the wires. Notes: Take notes or a photograph of all wire solder points. White = Left Red/Red = Right Black/Copper = Ground
	Take note of original cable strain-relief pattern if needed.
	End of cable has too much memory of strain relief coil - this will be cut off and used for the modification from the new socket to the left channel driver.
	Remove the strain relief grommet - pull it out from the inside of the cup.
	Pull out the frame from the cup starting with the side without wires.
	Now the cup is clear of all other parts and is ready for modifying. Notes: Keep driver and other sensitive parts away or under cover in case of plastic dust from drilling/dremelling.
	6mm drill bit is used to increase the size of the hole for the threaded part of the socket.
	Drilling

	It doesn't look much bigger. Original hole was about 5.5mm.
	The thread is not long enough to thread through this hole and reach the other side. The main body of the socket needs to be recessed into the body of the cup slightly. Use a rotary-tool to carve out a recess at a depth of about 2mm.
	Now the thread pokes out just enough for the screw-nut.
	Now is a good time to check that your plugs of choice are not too big and clear the cup edges.
	Cut the cable here to remove angled/curved parts. Note: Keep this cable, it will be needed later.
	Do not strip the cable more than needed
	Cut three cables from the off-cut from 2-steps above. Also shown: the cable is prepared with socket housing and heat-shrink tube. Note: No more info about original cable - there are enough mod tutorials about this elsewhere.
	Solder the three off-cut cables to the socket. Make sure the colours correspond to the correct channel. Note: I already soldered the new plug onto the original cable and plugged it into the new socket - then I used a multimeter to determine which terminals correspond to which channel.
	Solder new socket to left channel driver.
	Solder right channel cables to left channel driver.

	Attach the socket to the headphone, and screw it on tightly.
	Put the damping material back in the correct orientation and over the cables. It should make direct contact with the driver with no cables between them.
	Cables should be folded around the damping material.
	Fin.