Hello, I'm the new owner of a Marantz SR7300 and I was wondering if other 7300 owners have this very low level high pitch hiss in their speakers when they get really close to them? This hiss is almost impossible to ear at normal listening distance and is not affected by the audio levels. It's present on all speakers (except headphones) and this on all audio sources. Is this "normal" machine noise? How about yours? Thanks for your time.