This is a question for M-2000 users. I recently acquired a NOS M-2000, and I'm very happy with it except for one thing. The graphic EQ on the FET channel increases the noise floor by a small but noticeable amount when switched in, even if set flat. The tube channel does this also, but the hum is not nearly as loud (both channels set to comparable volume). The level of hum in the FET channel when the graphic EQ is switched in is such that it would not be usable for recording. I had it checked out by Professional Technical Service in Wheaton Md. They agreed it's noisy, but could not find any evidence of a problem. ProTech talked with Mesa, but nothing conclusive came out of it. Mesa suggested I ship it to them for service. They also said there are several different revs of this amp, for what that's worth. Can anyone confirm or deny that this issue is inherent in the design of the M-2000? Thanks!