Hi, thank you very much for you reply.
At this moment I'm goint to try to replace the DC coverter, though I'm very sceptical about the whole thing..; the headphones I connect in the front socket work perfectly, so it appears to be a problem with the wireless transmitter or the wireless headphone; not with the system amp itself...
If that does not work I may try to test the system in a different house; I try different rooms in my house, but not a total different location. If that does not work I may return the system and I'll ask for a repair or ask if they can replace them for another different system. I don't mind if I have to pay extra, money is not the problem (if it is not too much

Thank you again, I'll keep you posted.
cheers