Xperia sound issues

[Guest spankster]

Hi - when I plug headphones into the X1 I get a noticeable background hiss - it is not too bad on the headphones supplied but when I plug in my Ultimate Ears earphones (which are really high quality) the hiss is very noticeable. I get it in any audio at all (even the beep when I turn the phone volume up).... Now - this happens on my mp3 player but the hiss is very quiet and you only notice if you are listening out for it ... but ... it is very noticeable on the X1. Does anyone else get the same thing happen? Has anyone solved it or do you think it might be a faulty handset?

Thanks