Speaker Hum

Are your outlets really grounded?  My house was built in 1962 and most of mine are not. A previous owner replaced outlets with GHI outlets for some reason and they’re NOT grounded! I had to run a new circuit to my listening room.

BTW, have you tried a cheater adapter? That has helped me more than once.

Certainly one of the more frustrating situations....In my case, after a lot of trial and error, my problem went away after I realized it was the wifi router. Moved it further away and problem disappeared for good.

If you listen with headphones  is the hum still there?

(I had an integrated amp that had a voltage leak from one of the components in the power amp section... headphones sounded great but speakers had a hum)

Sorry @dpop but all GFCI outlets will work without a ground. It is surge protectors that need.a ground.

Gfci outlets compare the current on the hot and neutrl and trip when they are not equal. Ground not required, but you are required to stick the little "no ground" stickers on.

@erik_squires 

all GFCI outlets will work without a ground

You are correct. I never knew that before. Thanks for pointing that out! The situation could be very deceiving for some (especially audio-enthusiasts plugging their audio equipment into GFCI's that they think incorporate a true earth ground), since the GFCI will trip when needed, even though a true earth ground may not be present on the particular GFCI.