VOX Wah Troubleshooting

[Mages]

Does anyone know how to get yr wah to stop picking up radio stations? I'm getting tired of jamming out with Robert Seigel.

[Mr.Ripley]

Better shielding?

[Will]

Hard to shield a wah pedal since the top needs to be partially open for the rack and pinion.

Does it pick up radio if you run it off just a battery? Has it been modified in any way?

[Mages]

yeah, it's battery powered only. as far as I know it hasn't been modded. I've opened it before and it seemed very stock. it's one of the reissues, the V847A I think...



the shielding idea doesn't work so well, as the grounded parts of my guitar I think are actually acting as the antennae.

[Will]

That's a tough one. The culprit is probably the inductor, though I doubt a new inductor would act differently. Some areas are just prone to radio interference. Maybe you could use an inductor-less wah like a Morley?

[Sloan]

you have to play HEAVY AS FUCK RIFFZ to repel the signals of gay

[paul_]

Construct a chicken-wire fence around your gear.

[Mages]

it's one of the reissues, the V847A I think...

ok, it's just the V 847, no A. I have no clue what the difference is though.

Maybe you could use an inductor-less wah like a Morley?

that is precisely why morley wah's suck. they dont sound anything like a "real" wah.

maybe some inductors are more prone to radio frequencies than others? the only way to find out would be if I got another wah and tried to use it in the same place.

[NickS]

Does anyone know how to get yr wah to stop picking up radio stations? I'm getting tired of jamming out with Robert Seigel.

If you're getting radio only when the wah is in circuit, radio frequency is getting into your wah. You could try putting an inductor on the signal lead; either a little ferrite toroid that you wrap the input wire round or a ferrite tube that the lead goes through.


You might even make your own by winding the input wire into an air-cored spiral, or even hot-melt an iron nail into the core of the spiral.

Alternatively, a simple low-pass filter with 1K resistor followed by a 1nF capacitor should take care of it.

[Mages]

oh, ok, thanks man, that was really helpful. yea, it is only when the wah is on.

those ferrite things are like what some computer cables have on them right? so you should put it on the cable coming from the output of the wah?

the low pass filter is a good idea too though, since the wah tends to be unusably ice-picky at the top of its sweep.

[NickS]

oh, ok, thanks man, that was really helpful. yea, it is only when the wah is on.

those ferrite things are like what some computer cables have on them right? so you should put it on the cable coming from the output of the wah?

the low pass filter is a good idea too though, since the wah tends to be unusably ice-picky at the top of its sweep.

Yeah, that's the sort of thing they use to eliminate interference, but you can use them to reduce pick-up as well, so you can use them on the input. They're suppose to be a radio frequency block either way. If you think the wah is detecting the radio picked up from your guitar bits and pieces put it on the input, if something in the wah itself is picking it up and your amp is doing the conversion to audio, put it on the output - try both and see which works?

The LPF values I quoted you have a corner frequency around 159kHz so won't do much to take the ice-pick-y sound off your signal. I'd either turn the wah pot so that you don't get to that point or do a mod (resistor in series with the pot? That'll change the sweep characteristic slightly too.) I expect there's a whole bunch of websites devoted to modding wahs (e.g. Geoffrey Teese's Wah World? I only read a couple of threads there).