Radio station pickup

[AndrewCE]

I know this is probably a simple question, since i've heard of this specific problem in many places before(but never a solution other than shielding), but how do you keep radio stations from being picked up by a specific pedal?

I recently cloned a fuzz face (negative ground, with a buffer in front of it) and it's picking up a mexican news station. It is especially audible with the pedal volume on 0.

Notably, the circuit is not housed yet, but the problem occurs on breadboard and on my PCB which i tested.

Any suggestions? I'd like to remove the radio pickup before i house the PCB if possible.

[bassmannate]

 More than likely, it will go away if you house it in a metal enclosure and attach the metal enclosure to ground in some way such as an un-isolated (doesn't have any plastic washers) jack. It's not uncommon to get noise like this since just about anything above ground can act as an antenna. That's why shielding is so effective to cut it. It effectively surrounds the circuit with "ground." Any RF coming your way then gets caught by the metal enclosure and shorted to ground.

[AndrewCE]

that's what i thought i'd have to do. i just didnt want the hastle of removing it from the enclosure to fix it later if that didnt fix the problem. i was wondering if there was a design issue that could have been causing it.

i'll house it when i get the box, but until then, does anybody else know of a way to maybe fix the problem sans-enclosure?

[.Mike]

Check out this post... it might help.

http://www.diystompboxes.com/smfforum/index.php?topic=77212.msg633030#msg633030

[tatter]

I recently bought the Dunlop Fuzz Face reissue (blue silicon one) which sounded great apart from the horrendous radio interference. I was a bit disappointed at first.

I used 2 planet waves custom pro cables to connect the pedal to my guitar and amp which are sheilded really well. Anyway i noticed on one end of the cable it said "shielded end" so i swapped the cable around so the shielded end of the cable was in the pedal and the non shielded end was in my guitar, and the interference completely disappeared.

The cable was acting like a radio antennae until i swapped it around. I think shielded cables used correctly are the answer unless you want to start adding loads of caps and resistors into your pedal (which can change the sound). I didn't realise how important shielding really was until this experience.

[newfish]

How does that work then?  Cables shielded at only one end.

Is this like a star-grounding for guitars?

I'm asking because I'm a little confused.

[tatter]

The shielding goes the whole length of the cable but is connected to ground at one end only. If it was connected to ground at both ends it would create a connection and not reall be shielding anything (i think?). Whatever it does, it works.

[wavley]

I like those planet waves cables for that very reason.  I personally use a combo of those, George L's, and Mogami's depending on where it is in my signal path.