Tmmvinyl,
Thank you for responding back to my post.
You have found and solved your apparent ground loop hum problem.It is not caused by the AC grounded branch circuits wiring feeding the amps. The type of branch circuit wiring that was used and the very short distances, lengths, of the runs rules out the chance the ground loop hum is being caused by the branch circuit wiring, imo.
The problem lies with the mono amps. If Ralph from Atmasphere
is following this thread he is more qualified to give you the answer why.
It's a good thing the manufacture of the mono amps incorporated the ground lift switch on the amps. The switch does not lift the safety equipment ground chassis connection from the safety equipment grounding conductor of the AC power cord, That would be dangerous and UL would not give their blessing and safety approve, List, the amps. The ground lift switch lifts the signal ground, B- DC power rail, from the metal chassis of the amp,thus breaking the ground loop circuit/s that is causing the hum.
So the bottom line is, it safe to lift the signal ground from the chassis/safety equipment ground.
Jim.
Thank you for responding back to my post.
My mono power amplifiers have a ground lift switch. When I flip the switch, my system is dead quiet. I just don't like the idea of having to defeat ground to achieve silence. This seems dangerous to me.
07-18-15: Tmmvinyl
You have found and solved your apparent ground loop hum problem.It is not caused by the AC grounded branch circuits wiring feeding the amps. The type of branch circuit wiring that was used and the very short distances, lengths, of the runs rules out the chance the ground loop hum is being caused by the branch circuit wiring, imo.
The problem lies with the mono amps. If Ralph from Atmasphere
is following this thread he is more qualified to give you the answer why.
It's a good thing the manufacture of the mono amps incorporated the ground lift switch on the amps. The switch does not lift the safety equipment ground chassis connection from the safety equipment grounding conductor of the AC power cord, That would be dangerous and UL would not give their blessing and safety approve, List, the amps. The ground lift switch lifts the signal ground, B- DC power rail, from the metal chassis of the amp,thus breaking the ground loop circuit/s that is causing the hum.
So the bottom line is, it safe to lift the signal ground from the chassis/safety equipment ground.
Jim.