I have a Marantz SR4200 and am very impressed with it, as my first excursion into the home cinema experience. Lovely sound, acceptable looks, good features. However, the unit itself suffers from a very slight transformer hum, which is really only audible with the unit powered up with no input or when muted. It does not occur when in standby, and does not make it through to the speaker outputs. Does anyone else's SR4200 suffer from this? When replying, please indicate whether you have 50Hz (like me) or 60Hz mains supply. Please don't take this as a negative experience, I'd still choose the Marantz if I had to make the decision again. I'm just curious if it is inherent in the model or a minor flaw in mine.