I had a similar thing happen to my HD280s. I replaced the cable with a mono 3.5mm jack on either earcup so that I didn't have to deal with it again. EDIT: I see yours are bluetooth. Do you know why they broke? You'll want to make sure that can't happen again before you do any big fixes
Do-It-Yourself, Repairs and Fixes
Share tips and tricks to keep people from throwing out that broken item. Repair before replace!
They just kinda started to decompose out of themselves. A bit like apples “environmental friendly” cables.I think the material got weak over time and because of repeated movement on the spiral caused it to tear.
What kinda freaks me out is that it doesnt look like any wire i’ve ever seen. The inside appears made of some Blue sticky stuff and there are single strands of copper wire floating inside that mess.
Ive never modded a cable and i know audio is particularly sensitive some i am a bit worried.
Just get some thin 2 wire cable, and replace, you can essentially use whatever cable you want. It may not be shielded, but it will work just the same. Even inside of Ethernet cable is good usable wires.
In addition to the advice from @beeng@discuss.tchncs.de, I would also say that stranded core, silicone wire will be the most flexible and will be more than durable enough. You shouldn't need too thick of a wire gauge. AWG 20 should be more than adequate.
I bought a replacement Sennheiser cable off ebay and it even had a mic (new function for me). Then it's pretty easy to solder in yourself if you know what you're doing. Left and right...
If you're going to replace the wire, heat shrink tubing is another option to make it look presentable.