Well after my zulu's failing earlier this week, I bought a pair of DC10-13.4's as a backup (doesn't hurt to have a good spare set). I tried calling the lightspeed repair center (tristar aviation), had to leave a my name & number, but didn't get a call back, so tried emailing yesterday but no response so far. I spent some time fiddling with the set last night, and it seems to be a problem with the music mute button (which I don't use anyway), some wiggling of the button caused all sorts of clicks and pops (not plugged into anything). I tried the headset again today in an aircraft and it worked fine. I will probably send them for a check anyway.