If someone hasnt said it already, i would suggest putting a cd or sacd disc in it and putting it on repeat for a few days. You dont have to have the system playing, just have it hooked up to a preamp. I did this with a Krell 280 cd a couple of years ago. Right out of the box, it sounded much much worse (hard and grating) than the inexpensive Denon dvd player i was using before. After letting it run on repeat for a few days, it was sounding much better.
RB
RB