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.
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