[rhalf]

Hi,
I repair headphones daily and I had been used to fixing any problem by replacing a cable or a plug until I met this mystery... It's an XB700 with tough past. First broken, then vandalized by someone with no clue, then saved and heavily modified, with possibly the best cable, profesionally fitted and all. Also some nice mods have been done to it that gave it a better sound overall, but here's the problem: the left side either works or not. It's not affected by anything I'm aware of. It appears to be totally ok for some time, say 6 hours. No noises, no breaks. Then i pick them on the next day and the left side is dead. Then a few days later it's working perfectly again. I'm not sure, but I think it gradually gets more silent before it totally goes mute. I used many different sources, outdoor and indoor. Any ideas what may be causing this? Is my pair haunted? Anyone had similiar problem?

 

[GREQ]

Sounds like one tiny connection somewhere in the cable or driver is loose.
 
Could even be the voice coil connection to the driver terminals (however ridiculously unlikely)
Once I had something similar and I thought I was going crazy. Turned out to just be the plug which only worked one way, then if I twisted it 180 degrees in the socket, I would lose sound on one side because gravity would pull the cable to the side which would disconnect the sound.