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Radio reception problem

:

8/17/1999 6:02 PM

Radio reception problem

Hi !

I think it's an usual question.

Yesterday, when I protoed a Doctor Q, I could hear radio in my amp at particular settings of my Doctor Q. So, it made me laugh 1 second and I put a 33pF between input signal and ground. But it solved nothing.

I put directly the input of the effect to ground to see if my guitar was an antenna or not. I could still hear radio. It came from the pedal itself. And the radio is really loud!

Today, I tried to make the Harmonic Percolator and I had the same problem.

I think it comes from all the wires in the proto. Has anyone a solution for it ?

8/17/1999 8:39 PM
Doc	Is it a single, local AM radio station?

8/17/1999 11:02 PM
R.G.	Worse yet, is it country music?? *<

8/18/1999 6:57 AM
Aron	ahahahahahahah!!!! No, NOTHING can be worse than.... FUSION! (ducking)

8/18/1999 7:26 AM
Arnaud	Doc: I don't think it's a local station because the one I heard is well known. Maybe it's broadcasted on AM band but I don't think so. R.G.: Think it would have been an accordion thing in France! Though I'm living in this old country, I really like your country music (old tunes, I mean...) Aron: I hope you meant JAZZ FUSION !

8/18/1999 1:37 PM

The very strange thing here, is the same radio with two boxes! I'd like to know whether it happens with a different amp. Normally, only AM can be picked up by a fx box. Either the RF is getting into the guitar and/or guitar lead & then

rectified in the FX (but, that cap should have made a difference) or it is getting into the output lead to the amp,in which case maybe a cap at the OUTPUT of the box, or at the input to the amp.

BTW, RF pickup REALLY plagues theremins! I had one warbling away & the osc was modulated by the ENVELOPE of the radio!

8/19/1999 8:07 AM

I think I received 2 different radios with the Harmonic Percolator and the Doctor Q (don't know what I would receive with a Metal Zone...

).

I'm going to re-proto the Doctor Q and try to put a cap at the output. I suspect my power supply too (it's an old-fashioned transistor-with-zener-diode thing. I had forgotten to put a cap at the beginning of it). I will also try the proto on my keyboard amp to see what happens.

I'll tell when I have done it.

PS : Don't forget to post your guitar-theremin schematic, hehe !

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