First one that has come across the bench of D-Lab. Owner informed me that this amp had visited several repair shops for the same issue. Never resolved. Then he discovered me! So, the challenge was on. I did not want to let the guy down. He had already spent lots of time + money in hope of getting a quiet useable amp returned. Well, I believe I located the sources of noise + corrected them. I also discovered the idle current thru the output tubes was way to high. Causing the tubes to run very hot and would lead to a fast failure rate. Amp has been re-biased, now runs at the intended level. I did not use many parts for this repair, just used alot of time. A good source for the carbon + metal film resistors is AmplifiedParts.com. I would avoid buying these components on ebay, in my experience, some have been of poor quality. It's always best to buy from a reliable source.