I have lately been noticing a fairly low frequency hum, or more like what sounds like a 60hz buzz coming from the left channel when I first start the amp up. I have isolated it to the power amp by removing the input to it. Also while this is going on the left meter will hold a steady -10db read where the right side which is quiet is where it should be,-20db.. After switched off for several hours this issue occurs on startup, but goes away after it has been turned on for a length of time. After about 30 seconds from cold start, if I turn the left power level down and then back up the buzz goes away and doesn't return until the next day on a cold start. Any ideas on what this could be? The 3 main boards were rebuilt by echowars a few years ago and I replaced all the outputs with new ones that Glenn had recommended and since then this amp has been dead quiet (Except for the music of course ) . Although I haven't checked the DC offset lately it was quite low on both channels. One thing that has not been replaced was that big cap. . The protection board is all new as is the two main boards. . Hoping this thing isn't starting to develop a serious issue as living remote, it is too dang heavy to send by mail, and there is no one within a thousand miles I would trust to work on itl And besides, I already own a good boat anchor! Thanks for any advice you can offer.