Hi. I just noticed this odd thing today: Its only happened once, so im not too concerned, but it appears that the cut out switch in the headphone jack got stuck and wouldnt let me use the main speakers until i 'wiggled' a headphone connector in the jack. Odd one. But ive just noticed that the headphone jack no longer works. Ive i plug in my iPod headphones instead of my MX500s, it works normally again, and the MX500s work fine again afterwards. Anyone ever heard of this fault? Cause for concern?