Ground Loop


What is a ground loop? I understand that they can be caused by loose connections between components. What else can cause them? What are the effects? I have been told that humming from my power amplifier can be a symptom of a ground loop. True/False? Can ground loops cause damage to equpment?
mordenmail
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Connect all chasses together, so that you have one electrical point, use large guage wire. Now use one path to earth from the chassis - i.e. one wire. This should eliminate a ground loop problem.