I had a very bad ground loop on my system. Here is some REW measurement, all hum on the 60Hz. Worst curb with amplifier ON, woofer at full gain, no isolator. Best curb amplifier ON and isolator, woofer full gain.
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I tried a lot of things, at the end, this circuit eliminated all hum.
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Just to be safe, can a EE tell me if that will cause any problem to my electrical circuit or my equipment ?