How to eliminate FM RF coming thru turntable?
Some FM stations also broadcast on AM (or used to). Since demodulating FM by accident is virtually impossible something like this should be investigated. Many AM stations are required to REDUCE power at night because the signal travels so much further...to places where another station operates on the same frequency. Are there any practical jokers near you? |
I had a very similar problem also with a gyro se using a stock rb300 arm. In my case it was the tonearm cable picking up an am signal, I have no idea why but I was able to virtually eliminate it by reversing the phono inputs into the phono pre (plugging the left phono plug into the right input and right plug into left input) of course then I also had to reverse the leads from my phono pre to my linestage. Don't know if that's an option but it's easy to try. |
The RF I'm getting could very well be AM, I haven't listened to AM for years, so made this mistake, regardless, still getting RF at night, Spanish speaking talk radio -- any suggestions on brands of a ferrite RF filter? Will also try switching the tonearm cable. Again, thanks for all the suggestions. |
Here's an excellent paper, dealing with rfi problems caused by ham radio systems, but providing a lot of information that may be applicable to your situation as well: http://www.audiosystemsgroup.com/RFI-Ham.pdf Here's a link to the catalog of Fair-Rite, which makes a lot of these things: http://www.fair-rite.com/newfair/index.htm Radio Shack (you'll pardon the expression :)) sells some snap-together ferrite choke cores, part numbers 273-104 and 273-105 according to an older catalog I have. Hope that helps, -- Al |
