Quantcast Ryan's Guitars: RF Mod for Kingsley ToneBaron

Wednesday, May 07, 2008

RF Mod for Kingsley ToneBaron

Ever since I started playing tube amps I have noticed a problem with radio reception here in Memphis with different, random equipment. Not sure what the cause is, but it certainly seems to have something to do with this location because plenty of other locals I've talked to have had similar issues. It doesn't happen with every single amp or pedal, but there is no denying that the potential for radio reception in audio equipment is definitely high in Memphis, TN.

Unfortunately, I was picking up a strong radio reception on my new Kingsley amp and it was distressing. At volume and with copious amounts of gain (which is how I play most of the time) the signal was clear and loud. The station? Kix 106, the Mid-South's #1 Country music station. :)

Behold, the "RF mod"! I had to do something to get that twangy country stuff out of my amp! :) I am a rocker, after all, and I can't chicken-pick so there was no use trying to play along. I got this mod off the Gear Page message board from a post made by Randall Aiken of Aiken amps, a great line of amps in the Marshall vein. He suggests trying this mod if your amp is receiving radio signals only when the guitar cord is plugged in. This usually means your cord is acting as an antenna and that it is less likely that something more internal in the amp is the cause. If you're going to suffer from RF problems, this is the best variant to have because it is totally reversible and very easy to fix.

All you have to do is open up the amp, solder one lead of a .01 mF capacitor to the ground (sleeve) lug or the tip lug of your input jack and the other lead to the chassis of the amp.

(See photo left, note green capacitor soldered to the input jack)

Problem eliminated. And I mean completely eliminated as in zero radio signal heard at any volume. Basically what is happening is the amp is still picking up the radio station, but before it can pass through the cable jack and into the signal path, the capacitor "grabs" the transmission and sends it off to the chassis where it can cause no harm. Pretty cool.

Best of all, the mod costs only a few dollars and you can easily find these caps at your local Radio Shack or similar electronics store.


  1. Anonymous12:04 PM

    Does this have any other effect, like muffling the sound, or robbing the signal from the guitar?
    Can you supply a link to the post where this mod is suggested? Sounds like a great idea if there is no downside!

  2. There is no effect on sound quality. It works great! Here is the FAQ where amp builder, Randall Aiken talks about the technique (scroll down nearly to the end of the page). http://www.aikenamps.com/TI_Aiken_Q&A.html