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Electrician's advice wanted: safely lifting ground

Hi all,

I've got a ground loop in my system between the preamp and multiple amps. The cheater plug experiment on the amp power cords not only solves the hum but also lowers the noise floor a bit more. So I would like to do this correctly in a safer, more permanent way.

Bringing all of the power cords in the system to one socket helped also but isn't as quiet as with the grounds lifted.

Can I change the circuit breaker to a GFIC and then tie ground to neutral at the wall socket so that there are no adapters involved? If this isn't the way to go please advise on what is. Even if I don't do this myself I'd like to know so that I can talk with an electrician.

Thanks
dan_ed

Showing 1 response by jea48

jea48
4,673 posts
 
Yes, it is two paths to ground when one amp has a connection from input to chassis ground and one does not. Because chassis ground is relative to the transformer ground on each amp, and the transformers don't tap at the exact same voltage, so there is a potential created between the two amps. The slight ground current is running from one amp to the other via the input cables. Two paths to ground.
Dan_ed,

Then what you are saying amp A had the signal ground connected to the chassis ground, amp B did not. Correct?

Because chassis ground is relative to the transformer ground on each amp, and the transformers don't tap at the exact same voltage, so there is a potential created between the two amps.

the transformers don't tap at the exact same voltage, so there is a potential created between the two amps.
Primary or secondary windings? Can you be more specific....

Over the years I have read threads where guys with mono amps tried everything to rid them selves of a ground loop hum. Only in the end forced to use ground cheaters.

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