McIntosh MC451 amp mid-hum. Anyone have that?


Have new MC451s - burning them in - but have a hum. Have done the usual diagnostics (swapping power cords, different outlets, with without conditioner). Even when the XLR is unplugged there is the "slightest" hum.

None of my solid state (including the low solid state in the MC451 or oddly, the tweeter) have this issue.

Perhaps it is a burn-in issue. Curious if any others had this?

 

uberk

Wi-fi router is in closet. 10G switch is in a different outlet (and during the test - isolated).

I have the MC462 and have a faint hum when turned on.  I was told I need a DC blocker because there’s DC in the electrical line.