I think that calls for a teck to come and answer, I don't touch AC I have a qualified person for that stuff, but one thing I do know and have seen is high and low voltage wires need to be all by there self not running side by side, side by side is a big problem.

the DC should have a common there will be but if one of them is wrong it can loop the noise through everything what it sounds like it is doing from the drivers, it's close to what I had but that was a bad AC earth leak and one shield connected at each end what was very hard to find it was years.