Seems like you need to "float the ground" that is to say you need to take a trip to your local home depot and get a few "ground cheaters" they are cheap- real cheap. And try one here and one there until you get the hum gone altogether, this is not uncommon and an easy fix, once its done you needn't worry about it again. Its a real shame no one makes an audiophile grade ground cheater :(. Good luck! |
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. |
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 |
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. |
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 |
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. |
Thanks everyone for your great suggestions. I will consider them all. Again, much appreciated. P.S. I'm not so sure now that this is a true ground hum problem after all. I usually listen only to a local college FM station that plays mainly jazz and classical.After trying without success the cheater plug on all components, I tried some other FM stations and the hum wasn't there. I then went back to my regular station and the hum was only there, so I thought maybe it's with the radio station.The strange thing is the hum decreases and increases in volume as I move toward and away from my amp. Then, while fiddling with my tuner( modified 1980's Sansui T-80 analog)I pushed the stereo button to mono and the hum disappeared completely. Then when pushing the button off and on repeatedly, the hum would come and go as well( mono=no hum,stereo=hum ). It was nice to finally eliminate the hum, but listening to mono is not my cup of tea. Any further suggestions ? |
What is your antenna situation? If you improve the reception, it may solve your problem. A good attic or roof-mount directional antenna with a rotor is always a good idea. |
I am using a high-end dipole called the FM Reflect from C.Crane,Inc. I think I paid around $60.00 for it.It is mounted on the wall behind the system, carefully camaflouged by bookcases so the wife will leave it there. I may go for an outdoor unit, but FM is not my main source of listening. I'm trying to figure out why I get this background hum in stereo and not in mono. |
Well, I've isolated the humming problem to the FIM outlet. Apparently I didn't install it right. I am going to get an electrician in next week to put in dedicated outlets. I'm tired of sharing electricity with the rest of my house and neighborhood.I recently read a good review of an AC filter called the ISO 1100va. Can someone share their thoughts on this item ? Where can I buy one ? Thanks again for all your help in troubleshooting. |
Well, I thought I isolated the problem when I started searching the threads under "isolation transformer" and I found a post about coaxial cable causing ground loop hums. I didn't even have my cable hooked up to the T.V., so just for kicks I unscrewed the cable from the wall outlet and what do you know,the hum diminished dramatically.The cable outlet is located right next to the FIM outlet. I'm going to try a Radio Shack trick or two to hopefully resolve this issue once and for all. I'm still going for the dedicated lines, though. |
Glad to hear you've determined the ground loop hum issue. With regard to the AC filters, I'd like to suggest you consider the Foundation Research LC-1 and LC-2 in-line power conditiners.
Though not inexpensive, the LC's begin to look inexpensive when you consider they come with their own power cables and then compare their costs to other excellent quality power conditioners along with high-priced power cables.
Not to mention, with the Foundation Research in-line power conditioners, you are able to take full advantage of all your dedicated lines since you would use one LC per component.
-IMO |
