Hi Gnana- Some transformers hum. It can be caused by a variety of things, including some slight DC on the line, or by other aspects of "dirty" power resulting from things like dimmer switches, fluorescent lights, or certain kinds of motors on the same phase of the power distribution box as your amp. It can also be a mechanical vibration type hum which can sometimes be eliminated or reduced by tightening (but not over-tightening) the transformer hold down bolts or nuts. It will not cause any harm to your components and if your speakers are dead silent, should not have any effect on sound quality.
10 responses Add your response
If you bought an amp new, noticeable transformer hum may be part of warranty service. However, a SLIGHT HUM may be in all their amps that are using that type of transformer.
Swampwalker has provided a possible fix. In the case of DC on your power line, there are units that filter the DC such as the Emotiva CMX-2.
FWIW, I bought a McIntosh preamp here on Audiogon that had a slight, but audible, hum that did not affect the speakers. Someone on this forum suggested that I replace the hard feet with sorbothane ones, which helped a little. I noticed that when I lifted the preamp the sound stopped completely, so I loosened the screws that hold the cover down. Surprisingly, it is now silent. Can't hurt to try it!
I owned this amplifier several years ago. It is actually a very good amp. Mine also had the transformer hum. Unfortunately it was not due to DC on the line. To solve the problem I removed the transformer fastener and put some damping pads under and on top, then refastened it. This helped quite a bit. Unfortunately I cannot help with your other issue.