I purchased this unit new last October and have been extremely pleased with the sound, which is why the following problem is kind of bummer. I did make a point buying it from an authorized Sony dealer so I'm still definitely within warranty if in fact this is something that is covered. I get a small humming/purring sound through the first few tracks (one or two or three) after pressing play. The humming sound is not there if the unit is turned on without playing, just during playback. It then seems to go away. If I press stop in the middle of a song, the humming ceases. Here's the thing though: I have this unit in our bedroom so I tend to play it later at night and at a lower listening volumes which makes this humming more audible than it might be otherwise. Its not overbearing but just loud enough to be slightly irritating when I'd otherwise be getting lost in the music. Anybody have any ideas on what course of action I might take? I've never had a problem with audio equipment before this so I'm not sure what to do. It seems that this unit has been discontinued (I read elsewhere that production ended in Feb. of this year), but hopefully Sony would still cover this if it is considered a design flaw or some kind of defect. The unit has not been modded; its still in its stock form.