i would try other headphones, i vaguely remember others having this issue and it was due to the impedence on the output/headphones not being compatible... not what anyone wants to hear if you like the headphones you have... but it's worth trying for troubleshooting issues if you have some other sets around.
Thank you so much for you fast reply.
It works with my iPod headphones... but not with my Sony MDR-7506!
At least I'm relieved, I know that my POD X3 Pro is not defective.
I'm having terrible white noise with my new Sennheiser HD650s. They're 300ohm rated so shouldn't present a problem? My former Sennhesier HD 25 IIs didn't have this problem and they are 70ohm. Is there anyway of getting round this other than to ditch my brand new cans?
Please take a look at our Headphones FAQ. It may shed some light as to why you are getting noise through your Sony headphones.