Gettin` rid of RFI

[wilson]

Any tricks to get rid of RFI without buggering up the tone??

[R.G.]

Yes.

[aron]

Check out this forum:
http://www.diystompboxes.com/smfforum/index.php?board=10.0

[brett]

RFI in what?
The electronics of sound signals are mostly at frequencies of 30 Hz to 10 kHz (12 kHz if you've got good ears).  Radio frequencies are mostly 100kHz up, and most commonly at 1MHz (AM radio) to 5 GHz (cell phones).  You'll notice that there is plenty of gap between the two, which makes it relatively easy to filter out the radio frequencies.
Other noise, such as secular or low-frequency electro-magnetic bursts and power supply fluctuations can be more difficult to filter.  These often come from flouro lights, arc welders and faulty car ignitions.
What sort of circuit, what sort of shields and what sort of problem do you have?
cheers

[wilson]

i`m foolin` around with Fuzz Face type builds.

i`m gettin` RFI when the pedal is on and my guitar volume is off.

Thanks for your help.

[aron]

Fuzz Face? Check out the FAQ above.

[wilson]

Anyone ever try out ferrite beads???

[punkin]

A couple tricks...ferrite may work...the idea there is to keep the RF out of the circuit in the first place. In my opinion, that can be harder to do than you might think. Likely what you're picking up is an AM radio station. If so, you need a detector in the circuit for this to be heard. Diodes and transitor junctions are perfect for this. IF you were to bypass the junction with a small capacitor where the detection is taking place, you kill the interference source...the RF/AM modulated signal never gets a chance to be rectified then amplified.