Yeah I understand u had 2 of your UE1 went bad,that's not good......you sure only the 3.5mm jack side went bad?for both? even if the memory side or pins or any part of the cable goes wrong the sound will not be good on that particular channel,for that matter. I had mine into same issue and found the legit reason,posted my findings,fix on this forum. if you are 100% sure on the jack/strain relief on that, then it is more likely you mostly slide into your pocket with or w/o device? just my guess. :D
we'll be happy if FiiO would've already heard this and may be new RC-UE3 will have 90 deg angled jack against straight, next year. Again FiiO NEVER announced the said model but just a small expectation from us.