Acoustat TNT 120 hum

[Larry Z]

I have a TNT120 that I have owned since 1984 along with a AGI 511a pre amp and Magnepan MG1b's and just updated to LRS+'s.
I have always had a very low hum out the speakers from the beginning that couldn't be duplicate at store. It still happens with only the amp plugged into 110v socket with the ground connected or not and the speakers connected with Kimber wires. The manual states "The only Way to prevent this hum is to float this ground".
Any help would be nice. Thanks Larry

 

[rayma]

Often this can be fixed by inserting a 10R 1/2W resistor in the connection between each RCA jack common and the audio ground.
(There is already an impedance connected between the audio ground and the chassis.

 

[anibal]

I suggest to do a quick experiment: take a power strip and plug all your audio devices into it, this way you will have a single ground point and you will be avoiding ground currents caused by differences in the house wiring.