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Please help I have a strange grounding problem

I recently bought a FIM 880 outlet and installed it myself. I plugged in my amp and cdp but I'm getting a fairly loud "humming" when I play my tuner only. I don't have dedicated outlets( I'm in the process of making this my next project)so I have my tuner plugged into a Monster Cable 2000 outlet which is in another outlet on the same wall.Both outlets are on the same line as when I shut off the breaker there is no power on this wall. The strange thing is when I unplug the cdp, the hum goes away completely.It only comes back when I plug the cdp back into the same outlet as my amp. Another weird thing is when the hum is there and I get closer to my amp, the hum increases in volume as if my body is acting as an antenna. I'm not a technical guy,but it appears to me that there is some kind of a loop and by unplugging the cdp the loop is taken out. I would surely like some advice on this new and strange situation. Thanks for your help and advice.
sherod
sherod OP
1,690 posts
 
Thanks, Tim, but it seems to me that a cheap cheater plug to float the ground would also cause a degradation of the sound.Especially when one is using expensive power cords with expensive connectors. I have read that Virtual Dynamics makes some good cheater plugs. I'm curious if there is a better solution than cheater plugs to solve this problem.
blueswan
211 posts
 
Double check the connection to your FIM outlet, making sure the hot, ground and neutral are proper and secure. Remember, as you face the outlet, hot is on the right side, typically a smaller slot than the neutral. Also make sure this correct polarity extends to all outlets on that cicuit. It sounds like the polarity on your CDP might be different than the rest of your system. Your system should ideally be fed by a single dedicated outlet. If you are not sure, spring for a qualified electrician. I do not believe in cheater plugs. My system does not use them and is dead quiet
alexanderj
139 posts
 
Did this problem start with the changeover to the FIM 880?

Is the 880 an isolated ground style recepticle? FIM's website won't come up for me to check. If it is and it is mounted in a conduit type installation you may have NO GROUND connection to the "U" terminal. You may want to purchase an inexpensive (typically under $5.00) outlet tester (has 3 neon lites) and verify that the outlet has a ground as is wired with correct polarity.
stehno
1,453 posts
 
Since you installed the FIM 880 yourself, you can float the ground yourself by simply tripping the circuit, disconnect the ground from the FIM outlet, and then test.

Also, make certain that the house wiring to the FIM outlet are connected properly i.e. hot to brass or darker screws and neutral to the silver colored screws.

-IMO
j_k
234 posts
 
Don't float grounds except to troubleshoot - never a good solution. With a bit of rigor, one can find the solution... When I had an issue, it took me 20+ hours to figure this out - and I am capable of performing Electrician duties... One thing to try - if you have cable, sat. or antenna, disconnect any of these connections to see if the hum goes away.. You may have a ground loop thru a antenna / cable connection.
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