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RE: Higher Frequency Hum - Lifting Ground

Posted by 6bq5 on February 24, 2021 at 10:37:07:
There are a lot of possible issues that can cause hum.
Hum can come from the power mains when there are other items on the same circuit- like a refrigerator or Microwave
or from unshielded, or poorly shielded cables (interconnects, not speaker)
Hum can also be generated when all the components in a system have 3 pronged plugs and are using different circuits(mains power distribution circuits).

Typically you want only the power amp - or possibly the Pre-Amp to be grounded; however with two Mono amps - this gets tricky- but having only one of the amps grounded may help.

It would also be good to know what your system consists of - TT, Pre Power- Monos- speakers - that's it; or ....

TT systems can pick up hum a bit more easily as Phono stages have typically more gain than line stages

Placement of amp/Pre-amp, etc can also affect hum-