paulchung 發表於 2016-11-22 13:18
Point of view on electrical part, i think the current sound would be produced on speakers due to b ...
The noise is caused by a phenomenon called ground loop. It has nothing to do with bad contact or magnetic field. It is so caused by multiple paths to the ground. That is why some Ching would simply cut off the earth wiring to prevent it from happening. See below link for more info
mdo 發表於 2016-11-22 22:46
The noise is caused by a phenomenon called ground loop. It has nothing to do with bad contact or m ...
Noted. understood.
I understand that interference ( 220V power create magnetic field to cut signal cable ) is affect extra low voltage system. Now i understood the ground loop is difference with interference.