After extensive research on the internet I have treated myself to this receiver. The value for money I think after a week try absolutely convincing and because there is already enough extensive reviews on the properties of the device, I will not go into it again. Now I seemed to have also unfortunately a device "caught" which was a clearly audible, deep humming sound. Since I am in this respect is very sensitive, I had already resigned to return to my regret the receiver. Looking for an alternative I am in hi-Forum (incidentally, highly recommended) chanced upon the contribution of a TX-NR509 owner who mentioned that a hum could be heard when the unit was TV stands in his Ikea, NOT However, when he raised it, or put it on the floor. The course I tried the same and behold raised, humming away! My receiver is also in fact a cheap Ikea Bank which may appear very well serve as a resonance chamber. So I disconnected the device by means of small pieces of foam under the feet of the pad and now there is absolute peace :-). So if anyone should have a problem, just try it.
