i've had mine for 3 weeks now with no problems to speak of. i notice a slight, and i mean slight, hum from the powered subwofer. but can only hear it when the volume is muted. it's so low, that once i turn up the volume to anything listenable, i can't hear the hum and/or it is nonexistant. honestly, i had a similar hum with my last rcvr. i think this is partly a problem with powered subwofers. they are similar to leaving a live mic in a room -- you always pick up some interference. remmeber, they are powered, so that current alone can cause a hum. it could also be improperly grounded line cables to the sub. i actually have a pc case fan mounted to the back of my entertainemnt center to draw heat out off the rcvr, and when the rcvr is muted, i hear the pc case fan louder than the "hum." and i consider myself to be a very picky user. i have high expetations for all my equipment. if there were an unusual hum, i would return this rcvr in a blink. in any case, i can't speak to the rest of you, but for me, with my particular 804, i see/hear no defect. it works perfectly (thus far, knock on wood) and i'm very happy with it.