It's from a pair of Sony MDR-CD780 headphones. I can't find a model number on the cable, and this is the only one I've ever seen. Any help is greatly appreciated!
Are those both ends of the cable? They look like 3.5 mm stereo plugs.
If so, it wouldn't be too difficult to find a cable with a plug on each end (at Radio Shack, for example), although they wouldn't be threaded like the upper one.
I have a cable exactly like that on my Sennheiser HD 435s.
There is a very narrow 3.5mm which plugs into the left earcup, and the other end has a 3.5mm threaded to take a 6.2mm adapter. It looks exactly as in your pic.
Try Sennheiser, or someone who does Sennheiser spares. I'm sure that as it's detachable, they'll sell replacement parts.
