Radio Interference Everywhere!!!

[solarplexus]

Hi there...

I'm having problems with radio stations deciding to chose my pedals as a receiver.  I never had problems with this before...

I have a Tonemender built, a modded GCB-95 wah, and a DOD OD250 diy, all picking up a little Radio interference.

I believe I should put a 10k in series with a 100pf from input to ground... am I right ??  Should I do this with all the 3 pedals ??


Also OT :  My OD250 is kinda noisy, even though I used all metal film resistors... I use a RS LM741... could it be the IC???

Should I change it to a TL071 or something else ?

THANKS FOR YOUR HELP!!!!!!!!1

Matt

[Meanderthal]

10k in series with a 100pf from input to ground... am I right ??

I believe just the cap is what ya want, the resistor might cause a volume drop or impedance weirdness. I might be wrong... never had that problem yet. (but I live in a rural valley- not all that much to interfere here, I may eventually have problems at a gig... not yet though)

The only precaution I take is always using a shielded enclosure.

I've heard Ferrite beads can be helpful too...

I use a RS LM741... could it be the IC

Yeah, the 741 ain't a quiet chip, but it has some good grit for the D+/OD250... try the swap, might work.

[db]

I believe AM signals are quite partial to a bit of rectification...?!?!

[petemoore]

all picking up a little Radio interference.
  A fair bit of diddling around may help isolate the reciever, a fair bit when you have many pedals and cables to check by process of elimination.
  I haven't done this in a while and don't think I need to...
  Starting with a cable from G to A.
  Then another, comparing the sound with the amp loud enough so any small differences could be heard.
  If they sound the same, figure you have a good cable comparator.
  I've upgraded longer cables and do notice a difference.
  Do every cable like that, perhaps with 1 box and cable so you don't have to get the guitar plugged in the amp with a 3'' cable.
  Then add stuff 1 at a time. Use the bypass switches to try isolating further

[roknjohn]

Shielded box and proper grounding would be the first things I'd look into.

It's interesting that all 3 have the same problem. All gain related devices. Perhaps it is coming from somewhere else in the chain. Have you tried using different cables?

I once had a fella fight a radio interference problem that turned out to be caused by the pickup in his guitar!! Go figure.

[Meanderthal]

 Gilligan picked up radio signals with a filling after the skipper popped him in the jaw...

[solarplexus]

well my setup is as follows :

Fender Jaguar HH - Boss Tu-2 - Tonemender - dunlop crybaby - thing modulator - Ibanez Fl-9 - OD250 - Whisker Biscuit - Amp

FX loop :  Aria PS-10 - Boss DD-3

I use ALL planetwave goldplated cables (even the short wires).

Could it be, COULD it be, that my Boss TU-2, feeding the 7 pedals (except the wah) would cause th problem??

Or COULD it be that the power supply I am using on my wah is causing the Radio Int. in the wah and travels in the rest of the chain?

Could it just be that I'm too much near a radio emitter ?  

[solarplexus]

Or could it be that I don't have enough buffered pedals in the chain ? (tonemender, thing mod, od250, whisker biscuit)

[Meanderthal]

 Hmmm... I guess I'd try the trial and error method as pete suggested, start with guitar-amp and add one device at a time, til ya narrow it down to the one/ones with the problem. Or, did ya already do that, and that's why ya mentioned the tonemender, wah, and overdrive?

Anyway, I doubt it's the power supply, and I think you have enough buffers...

Maybe try the small cap across the input on one, see if that helps, and if so... the other 2?

[solarplexus]

I'm sure it's those 3 cause the radio interference is only audible when one of 'em is on.

But I must add that the worst of the 3 is the wah... then the tonemender, then the OD250.

But I supose the OD250 could worsen the noise because it's already quite noisy (IC)

what do you think?

[GibsonGM]

I've heard of this type of RI coming in on wahs; I think there's a fix on the Dunlop website, try Google.  Something to do with the PSU and the inductor coupling, IIRC.    Have you taken the wah out of the chain and tried it that way?    Seems possibly PS related to me...how about just on batteries?

[Meanderthal]

 Ehhh... the 741 might be a little hissy, but it won't pick up radio signals all by itself. The OD is a dirtbox, it'll multiply any noise that gets in there...

The wah makes sense, I guess an inductor is an important part of a radio receiver... I recall Hendrix had the same problem, even made it onto a live recording once.

Yeah, go ahead and see if a batt. or other power supply stops it, can't hurt to try.

[rockgardenlove]

I'm right by a transmitter, so I'm used to this.  I've come to think that getting some radio at points in a wah sweep is unavoidable.  It's not audible while you play really anyways.  But with other pedals:
Make sure the box is grounded/shielding is grounded
Put a 22k-100k resistor in series with the input, and/or a small cap to ground.
For me it really helps to use a buffer too as soon as possible in the chain.  Mine is right after my Fuzz Face.

[solarplexus]

Thanks for the help guys!  Really appreciate it!

[Barcode80]

i'm shocked that no one seems to have mentioned building power. if these things are all plugged in to the wall at home, the slightest wiring quirk in the house and such will cause RFI. the music store i work in is a very old building, and when i play homebrew pedals there sometimes i get lots of RFI on high devices, but at home or at other gigs they are fine. building grounding is just as important.

[solarplexus]

Well the apartment I live in was built in the 70's so I guess maybe the wiring could be the problem. 

I guess I'll have to try it this weekend in the new bar were playing and hope for the best !!

[runmikeyrun]

I feel your pain.  I used to live about 1/2 mile from a 50,000 watt Radio Disney transmission tower  It was horrible, any unshielded leads or effects (especially on the breadboard) picked up "who let the dogs out" and Hilary Duff whenever connected to an amp.  Which was often as i swapped parts and debugged.  I thought i was going to lose my mind!  Since the RF was so incredibly strong, i knew when i had an effect (or my guitar cavity + pickups when i redid all that) completely shielded.  But man i don't miss that at all.  Now i live about 3 miles from a poop factory and on occasion i can smell the sweet smell of bacteria doing its work in the leach fields but it's way better than the hours of torture i endured in my basement.

I've had problems with these kinds of things in the past- hums, RF, etc.  Right now my cheap guitar with worse pickups captures a horrible hum from everything in my whole house.  Seriously.  It only goes away if EVERYTHING in my house is off, even the computer upstairs. 

One time i had a bad hum everywhere i played, turned out it was the totally awesome 25ft cable with clear red insulation.  I had a huge tone sucking going on in my pedal board, turned out it was a cable i soldered together.  I removed both ends and soldered to a different cable and same thing.  So one of the jacks must be bogus.  That and i've had others- fluorescent bulbs on (upstairs) power transformer in the power box next to my workbench, even the furnace and air conditioner.  Our guitarist had a horrible crunching coming through his amp right after he stopped playing the last note at one of our practice spots.  He switched outlets and it was gone.  The offending outlet didn't do it to my amp, just his.

Start as others have suggested- swap cables (one at a time of course) amps, outlets, power supplies (going to a battery eliminates all doubt about any PS) and ambient interference.  Try changing guitars too.  If this fails to do it, box up your effect and try it on a friend's rig with his stuff that is known good.  You basically want to get to a point where you are not playing through or with any of the stuff you started out with, eliminating things one at a time to find the offender.  Also pick up an outlet analyzer at Home Depot- it's a yellow oversized plug w/ 3 LEDS that you plug into an outlet- it tells you if you have bad grounds, swapped neutral/hot, etc.  I plug it into every outlet i play through everywhere i go. 

[sengo]

Hello solarplexus,
   
    I was having the same trouble with a pedal I made. I was picking up some foreign radio station. I just soldiered a small (.0022uF) cap across the input and ground about five minutes ago, and now theres no more interference.

Good luck,

Nick

[solarplexus]

Thanks guys!

I haven't had time to solder the caps yet, cause I've been swamped at work, jam, sleep, work, jam, sleep, change tires, doctor appointment, work, jam, sleep.. . . .. . . .. etc.

But I'm off tonight so I'll definitely try that.

A little OT but I put my Tonemender first in the chain... do you guys think I should put it after my rig, right before the amp, or first in the FX loop or just leave it as is ??