Tode Amp

[MCurtis846]

My tode amp picks up radio stations when used at my son's apartment in Buffalo.  This does not happen at my home on Long Island.  Any suggestions?

[Doc B.]

Not sure if you got the answer I sent to your email about this yesterday. The Tode input stage is very sensitive, and if the pickup or cable is picking up RFI the amp will indeed amplify it. A very well shielded cable and shielding foil in the pickup cavities should help, if they are not already in place.

[MCurtis846]

Hi Doc.  Thanks very much for your reply.  The amp will pick up a radio signal when just the cable without the guitar is plugged in, so I suspect it is a cable problem.  I have ordered a new, high quality shielded cable to try.  If that doesn't work, I will try shielding the pickups and pick plate on the guitar.  I'll let you know how I make out.  Otherwise, the amp is simply amazing!!!!!!   Thanks for the wonderful design!

[TubeTim]

Sorry I am late to the party....

I have a Tode that I was originally going to build then sell (enjoy making the kits!).  I tried it using it on a amateur radio piece of gear that required an amplified speaker.  It sounded so good decided to hang on to it.  Needless to say, it' in a strong RF field and was experiencing RFI.  A good shielded cable with all metal plugs helped.  A couple of Mix-31 ferrite snap on split beads did the job.  RF was travelling down the outside of the cable and into the Tode. This is not unusual occurrence.

Best Regards,

Tim

[Doc B.]

The OP solved the issue with a small filter box that had a phone jack input for a guitar cable and a short guitar cable to the amp. Inside the box is a 100 ohm series resistor in the hot leg and, IIRC, a 220pF cap from hot to ground. That could probably be installed in the amp very easily.