Tremendous RF problem -- phono stage is a radio

Rives...For many years I used shielded 300 ohm twinlead for FM signal. I am in a weak signal area, and noise from autos on the nearby road was a problem. It worked very well, but the surprising thing was that the shield was, by design, not tied to ground at either end. It was floating.

Another way (military practice) is to take a broom and clean RF off...:-)

Thank you all for your suggestions -- the "military" one is excellent. It turns out that I have some mu metal (the contents of one's garage are sometimes rather curious), and I can have it cut to fit the walls of a box that will cover the phono stage, not exactly beautiful, but the phono section is hiding in a cabinet anyway, so it won't matter. I suppose I could allso use an old wire cage that once housed a pet rabbit -- another long story. One wonders whether Faraday would be amused.

The various suggestions that have been made are worth a try. However, let me note that low impedance/high current circuits, which means a MC pickup and solid state amplification, are less likely to have your problem.

As noted above, it is an absolute "must" that you use shielded cables. Also, if you have your cartridge "unloaded" (e.g., 47kohms or higher) you might try a lower figure (higher loading), such as 1,000 ohm or 150 ohm, etc. Higher loading attenuates high frequencies that may be overloading the phono stage or otherwise causing it to act up.

A friend had this problem with a Transfiguration Temper V cartridge, but not his Lyra Titan, and the difference was the lower source impedance of the Transfiguration cartridge. The Hovland preamp he was using has a factory default setting of 100kohms. Choosing a lower setting (higher loading) cured the problem.