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Phono stage picking up radio signals?

The strangest thing happened this evening. I just hooked up my Whest phono stage and as I was letting it warm up I turned up the volume slightly to check the noise level and noticed a strange noise coming from the speakers. At first I thought it was a ground loop hum or some feedback, but when I put my ear to the speaker I distinctly heard music. I turned up the volume a bit and to my surprise I could hear and identify the song playing, followed shortly after by DJ banter. It was obvious I was picking up a radio station, but I don't have a tuner or any other radio device in the home. Can anyone give me a clue as to what might be going on.
clio09
raytheprinter's avatar
raytheprinter
1,234 posts
 
are you using unshielded ICs?
rich62
30 posts
 
I had the same problem (do a search in Audiogon). I was able to stop the radio station by using shielded interconnects, ferrite clamps and switching phono stages. This was a very annoying problem for me and I was close to giving up on vinyl all together and switching to digital. Good luck.
nsgarch's avatar
nsgarch
2,524 posts
 
There is no reason for a phono system to act as an antenna, even with a MM cartridge, with the possible exception that you live near or under a transmission tower, if you will:

1.) Make sure the turntable, tonearm, and phono preamp (if separate) are properly grounded to the rest of the system. If the separate phono preamp has a three prong plug, use a lifter (or "cheater plug") to disable the ground -- it gets its "ground" from the main preamp through the IC's.

2.) Use shielded IC's from the phono preamp to the preamp (and throughout your system, preferably) making sure the IC's have a "floating shield" (one that's connected to ground at only one end, usually the "arrowhead" end) and make sure the arrowhead end is at the preamp.

3.) Oh yes, and make sure the main preamp IS grounded at the wall!

That should do it.

.
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