Hi, I've got a two-year old Arcam AVR-200 that's worked flawlessly until recently. Recently, I've noticed that there's a hum/buzz coming from the speakers. The hum varies with volume and drops greatly when the unit is muted. The hum is much louder when the unit is in a surround mode then when in stereo. Changing inputs doesn't seem to affect the hum and disconnecting all the inputs and connecting to a different power mains made no difference either. Does anyone have any idea what could cause something like this? Have any other avr200 owners experienced anything similar? I figured I'd ask these questions here since you guys seem to know a lot about Arcam products. Thanks in advance.