Ground loop je problem. Resava se vrlo lagano. Resenje je da zvucnike/pojacalo nakacite u mrezu preko 'lopova' koji nema uzemljenje tj ima samo pinove za fazu i nulu.
Nesto ovakvo:
http://www.amazon.com/gp/product/B002N2RHY0/ref=olp_product_details?ie=UTF8&me=&seller=
sa wikija: If circuit 2 is an audio system, and circuit 1 has large AC currents flowing in it, the interference may be heard as a 50 or 60 Hz hum in the speakers. Also, both circuits will have voltage V_G\, on their grounded parts that may be exposed to contact, possibly presenting a shock hazard. This is true even if circuit 2 is turned off.
Drugacije receno sto imate jacu azdaju od racunara, vise overklokovan cpu i graficku koja moze bas dosta da povuce tokom intenzivnijeg igranja ovaj sum moze da bude nepodnosljiv. Tako je kod mene bilo i kada sam na kabl od pojacala dodao lopova sa 2 pina... savrsena tisina.