2. analog
  3. 1057675434

Unwanted radio signal from turntable

I have been plagued by a unwanted AM radio signal that appears when I am using my turntable. While it can't be heard when music is playing it is very annoying to hear a newscaster talking about the latest political scandel inbetween the voices of "Sweet Honey in the Rock".
My system is AR pre, Phonomena phono, Clearaudio turntable. It is in this chain that the problem occurs. The culprit seems to be the interconnect between the turntable and the phono stage. If I disconnect it from the turntable the radio station remains, so not the turntable or ground. If I disconnect it from the phono stage the radio signal disapears. I thought that it was due to a poorly sheilded interconnect (Kimber). I tried a different interconnect and the signal returned, any ideas from the analog gurus on how to deal with this?
agaffer
thsalmon
348 posts
 
You might try a different length of interconnect cable. Do make sure it is a shielded type.
twl
3,251 posts
 
It is also possible that it is coming from the internal tonearm wiring. These wires are normally unshielded and can pick up radio stations. Sometimes grounding the tonearm tube can help this, but you have to be very careful not to interfere with the free movement of the arm. Sometimes grounding the metal areas around the bearing or base of the tonearm can work instead. That would be preferable to having any additional wire touching the arm tube.
eldartford
4,262 posts
 
Clean the interconnect connectors and the jacks that they go into using contact cleaner (from Radio shack). In order to hear the RF signal it has to be demodulated, and some corrosion product may be doing it. If you listen closely you may hear a weird audio "soup" of all the AM stations in your area.
audiobugged
528 posts
 
Reminds me of the Partridge Family episode where Lori Partridge was picking up AM stations in her mouth after getting new Braces on her teeth.

Agaffer most people on Agon complain of getting bad AM reception, so in your case it's like a bonus? :)~

I'm w/ Twl on the Grounding situation, & Eldartford on cleaning the contacts if they are dirty?

Did changing interconnects lessen or strengthen the signal?
lourenz
14 posts
 
I can receive short wave radio stations with my Rega RB300, modified with the Incognito rewiring kit (Cardas). To turn them off: unplug the FM-antenna(s) from your tuner, twist the interconnects from the turntable to the phono amp and take care of proper grounding of your arm/turntable by connecting a ground lead to the phono-amp. This even lowered the noise (hiss) level a lot.
Hope this helps you too. Good luck!
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