Problem with Theta Miles

Hello, new user from Norway!
I've got a Theta Miles with a problem, it's very noisy! It's like standing in the shower, a remarkable hiss from the speakers, playing cd or not, it appears the moment I switch to the input it uses. Tried XLR or RCA, same problem. The problem follows the signal strength, it's worse when the output it set to maximum. (I use a integrated amp, and I've tried other amps, same problem) I use a rather sensitive pair of speakers (100db sens) but it's a problem on other speakers too, the former owner never had the poblem because it was connected to a poweramp directly and driving very low sens speakers (81db). The problem occurs in both speakers.

Any suggestions?

(Pardon my clumsy English, I'm out of practice)
Speak to Theta, they are very helpfull and provide good service.
Sounds like a bad capacitor or two. Theta can repair it for you.