Help!! Low level hum from FM cable sgnl


I'm using my cable as an the signal input to my FM tuner(MD FT-11), but there is a terrible hum now in the system. It makes no difference if I select the tuner or not(on the preamp) or if the tuner is on or not. I'm curious if a Monster Cable power conditioner (1200 I think-the one with the cable input) would filter this out or if there is another solution. Thanks
mailman199
Sounds very much like a ground loop problem. Your cable connection is grounded where it enters the house; if this is not the same physical point as the ground for your power panel feeding the preamp, you typically have a voltage differntial betweenteh two ground points, which is manifested as a hum in the system. Easiest solution typically is to reroute the cable ground to the same physical connection as the power system ground.
Had this problem as well... Monster 1200 (nor any other filter device) will remove this completely. One thing to do is to make the grounds common (keep in mind NEC & local ordinances)(I disagree with the previous post that this is the easiest solution in all cases). The other thing to do is to take $50 to your local high end AV dealer and get an isolation transformer for your cable. This device will pysically disconnect the ground from the cable respective to your tuner. I took the latter approach with wonderful results. Write me if you need help finding this device.
Per J-k a hum-bucker is probably the best answer. But I did find a cheaper solution for my rig. I happened to have on-hand a car-audio isolation transformer. Actually this is two transformers (left & right channels) in 1 package, available from a car-audio shop. Run the audio coax's thru them to your preamps' inputs. These coupling transformers are probably not the nicest thing for your FM audio signal, especially a Dynalab (I have one too) so the hum-bucker is the best solution.
J_k is right. Try an in-line "cable ground breaker", but not from your hi-end A/V store if they charge $50. It will only cost you $15 from a mid-fi store that deals with A/V installations.
I agree with the previous posts about less costly solutions than $50 (Sonance RFGI1)... There are versions as cheap as $8, but there could also be trade-offs with the signal quality. I got tired of trying a box for $8, another for $15, and then I did an audition of this one and it COMPLETELY fixed my problems (I had really loud HUMMMMMMM). I run a 65" HDTV capable TV, and even a minor problem with a cable, connection or signal will drive this thing nuts, The Sonance RFGI1 is a high end component, which also removed hum bars and some other rudeness that the CATV company provides me. You can experiment with all of the above suggestions, and they may work -- If you have more money than patience, or equipment that is finicky of its RF input, try the Sonance. I forgot to mention in my previous post, the monster 1200 and other devices like it have to tie the cable ground to the wall ground to comply with UL device manufacturing rules (all exposed metal must be ground potential). Good luck!!
Thanks for the help. So, I should get the Sonance RFG1 or comparable device? How much does the Sonance cost and where can I get one? Honestly I'd like to spend as little a possible. If anyone has other brand and model recommendations that would be great. Carter
Check out the sonance website for details. If you search altavista for RFGI1 it will only find sonance. Otherwise call your local AV dealers. You may not need the sonance quality for a tuner... My HDTV is extremely picky of cables, and anything in the signal path, hence why I ended up with sonance.
Hey, I just ran a wire with an aligator clip from the outside (screw) connector of the Cable to the ground on my amp and the hum was gone.
Jbherrin is right on with reference to the difference of potential. It's something that should be checked.