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
yeah, some folks are afraid of tube amps, imagine that. like capt. beefheart said it's "safe as milk" :)
Wow, what a great thread, I really like (and agree with) Elizabeth's rules for living, and who'd believe someone would actually quote Captain Beefheart. Way to go, Pehare. This thread has really brought out the "inner poet" in you two.

Regarding ground loops, consider trying Jensen input transformers just ahead of your amps. Totally solved my problem going from a single-ended preamp to my balanced only amps. Went from all sorts of noise (almost sold the Clayton's) to dead-nuts quiet. Go to their website and give them a call - very helpful folks and the stuff is not that expensive. BTW, since you have "multiple amps" be aware that they sell single line models of the transformers that may be logistically easier for you than the twin versions shown on the website. They will make them as you need, rca-rca, xlr-xlr, rca to xlr, and xlr to rca.
Outsiders do not appreciate the dangers audiophiles routinely embrace . . . all for the love of music . . . Courage!

yeah.. I'm sort of surprised too that the origin of the loop wasn't or isn't being addressed by the Jensen idea or some other like Dayton. Finding the unit causing it I'd think is the better approach, if after all, you want to do things the right way here.
Folks. I did contact the person who built/mod'd my amps and it was he who provided the solution based on my experiments to track it down. Once I opened both amps, the problem was clear. One amp was using wbt input connectors and had a connection between the ground rings and chassis ground. The other amp did not have such a ground connection. The are not mono-block amps, just two stereo amps bought from different people who chose different options as far as the input connectors are concerned. Things are still grounded through the power cords.

The cause is that the center taps on the transformers are not identical and you get a ground loop current between the amps when their inputs are connected together. Simple once I saw that one amp did one thing with input ground and the other didn't.

Not completely sure where I got the idea I originally posted about. Probably from reading forum posts. ;-) :-)