I had this exact problem as you describe and it was a bad connection in power dustribution board.

It is not dc noise on your power, it's not normal.

Meridian transformers are dead silent when working correctly.

Sounds mechanical and sound is from transformer but transformer is fine.

Problem is simple but tricky to find.


- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
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