it sounds like the system is not grounded. is there a ground fault in the wall power? get a polarity tester and check.
i do not think line level signals are high enough to cause such a problem.
it's a shot in the dark, i am not an electronics expert. good luck and happy new year!
ts
i do not think line level signals are high enough to cause such a problem.
it's a shot in the dark, i am not an electronics expert. good luck and happy new year!
ts