vox wah and fuzzface not compatible?

[zolee]

Hi,

 I recently built a vox clyde mccoy wah, based on the layout I found at fuzzcentral. I used the pot, inductor and box from my old Polish wah. I am really satisfied with what I got. Only when I connected my wah with my home-made npn, silicon fuzzface - that also sounds great on its own- it started to make a sharp noise as I turned the wah pot. Same thing happened when I mixed up the input and output jacks on te wah once. Is it a grounding-problem? Anyone knows what the reason might be?

[Ammscray]

The reason that Hendrix got his wah to work before the FF is because he had the UNIVIBE IN BETWEEN the two pedals...I don't know whether it had to do with impedance matching, or maybe the univibe put the two pedals back in phase (that's what it sounds like) but try it and you'll see...it's the only way it will work...and your univibe circuit (whichever circuit it is) must not be natural bypass (when it's off), in other words, the cancel switch just stops the phase, but the signal is still loaded down (or in the signal path) when on...the Jimi Hendrix secret!

[al3151]

If you look at some of Joe Gagan's fuzz schems you'll see that he uses a 250K pre-gain pot at the input  of his Easy Face.This is what I put on my Fuzz Face clone and when I use a wah before the Fuzz Face I adjust this pre-gain till the wheeeeee sound stops,now this does mellow the fuzz a little.If your wah is true bypassed you should be able to add a 250K pot to the output of the wah circuit so it would not affect your sound when in bypass mode.I haven't tried this but it makes sense to me that it would work and not affect the wah sound very much.I copied the following from a forum I don't remember wich but it sounds like this is whats going on here-
         "When I got home I noticed on the bottom of the Vox box -a white box- it's got 'EXP 103' in felt pen. And on the Wah itself, the only thing I've changed is the battery clip cause it was for a large battery that's now an obsolete size -one of those big square things- on the side of it there's been a Radio Sparespot fitted. 500 K, it's got 'LGD1' written on it but no date code 'cause it's British and a silver knob on the side. And that seems to control the Wah sound as opposed to the straight sound; it doesn't effect the Wah tone as far as I can tell. It possible does but it just comes straight off the jack at one end and onto the Wah pot at the other. So I suspect you can reduce the Wah sound which is louder than the clean sound but it's got that real chewy 'Voodoo Child' tone to it. I don't know anything about transistors but that's what it looks like. It's been modified by someone for some reason. Now, I don't know anyone in my history of local musicians who've ever thought to do anything like that. It's a very old modification; the cable looks like 13 amp light cable but it's clear insulated stuff. I dunno why it's modified or why it's got 'EXP' on it or why it's in it's original box."

[RDV]

From the FoxRox site:

Why it happens - Without getting into a lengthy discussion about electronic circuitry, here's a brief explanation of why this happens:

Wah pedals -
Most inductor-based Wah Wah pedals use the same basic circuit. This includes VOX, Thomas Organ, Jen, Dunlop, and many of the newer boutique Wah pedals such as Teese, Fulltone, Buddha, etc.. Of course, there are many modifications and different quality parts used in these pedals which makes them all unique, but essentially they all adhere the same basic circuit topology. The classic inductor-based Wah circuit has an output stage that is not particularly well suited to drive a load. If the output is loaded down, the result is a very narrow sweep, the low end of the sweep pretty much disappears. While most effects don't load down the signal enough to cause a problem, there's one big exception - the Fuzz Face.

FuzzFace -
The FuzzFace is notorious for having a very low input impedance. It's so low that it's actually the first guitar effect (that I know of) to feature true bypass. Yes - back in 1966, the designers of the FuzzFace realized that true bypass was required or else the input of the FuzzFace would severely degrade the guitar signal when the effect was bypassed.
The Wah + Fuzz Face combination - So when you take a Wah Wah pedal, and plug it into a Fuzz Face, and kick them in at the same time, you're creating the scenario. You have an effect (the Wah) that can't drive a load very well, and you're connecting it directly to the effect (the Fuzz Face) that has the biggest load of all. The result - with low gain Fuzz's, mostly germanium, you get almost no range from the Wah. With high gain Fuzz's, mostly silicon, you get almost no range, along with a howl that changes in frequency as you rock the pedal up and down.
Remedies - In order to avoid this scenario from happening, there are a number of things you can do , but unfortunately they all have drawbacks.

Here's a list of things that come to mind:

Put the Wah after the Fuzz, not before. The problem here is that you end up with a very intense Wah sound, which can be very shrill and deafening to most people. While some people have gotten good results from this, most agree that it's a pretty lousy sound.

Put a "clean boost" or "buffer" type of pedal between the Wah and the Fuzz. This cures the problem, but it creates a new one. You see, the Fuzz Face works best with no active circuitry between it, and your guitar's pickups. Any type of active buffer will kill much of the FuzzFace tone and make it sound more like a regular distortion pedal. It also affects the ability to "clean up" the fuzz by rolling back the volume knob on your guitar, one of the greatest features of the FuzzFace.

Put a resistor at the input of the FuzzFace to increase its input impedance. This helps to minimize the problem, returning much of the Wah's range and preventing oscillation. This is probably the best of the three remedies listed. But there's one considerable draw back - it takes away from the intensity and sustain of the Fuzz by cutting the input signal.

HTH

RDV

[Paul Marossy]

What if you have a Boutique Fuzz Face? I am using one, and it has a 1M resistor to ground on the input, but it still doesn't sound right with a wah in front of it... maybe it's just because the wah filters out a lot of the signal from the guitar?
I built a FET buffer to try putting on the output of my wah, but I haven't done any testing with it yet. When I get around to it, I'll post the results of that, too.

[RDV]

What if you have a Boutique Fuzz Face? I am using one, and it has a 1M resistor to ground on the input, but it still doesn't sound right with a wah in front of it...

The 1Meg resistor is a pulldown resistor to stop switch pops. The input impedance remains the same. Quite low.

Regards

RDV

[Gus]

The input of the FF is a low Z summing point.  The feedback resistor often 100k divided by the circuit in front(pickups and pots etc in guitar) of it is part of the gain.

 The FT 69 has a pot in series with the input of the FF circuit.  The 3tran/rocket Has an EF with a 10K before the FF type circuit.  Problem with this type of circuit is that the pickup is modeled with just a resistor.  A pickup is an inductive device, being inductive when used with a FF the first stage gain decreases with an increase in freg.  This limits the highs a little.  With the 3 tran I added a 16khz lowpass filter(.01uf and the 1K) at the output to kind of sim this.

I believe Jack had posted in the past about using a buffered inductor type.  What someone could try is a 1.5H to 2.5H maybe about 10k total R inductor on it own or add R inductor insead of of the 10k.  I have wound a 2H humbucking coil for a friends guitar it big and takes some time.

Doug H had a circuit for the wha to Fuzz problem I believe.


Gus

[petemoore]

Ya put the wah and the Fuzz in the same box [I think this may have ben done] but put a bypass on the buffer too...a little more complicated, another switch, but would give you everything you could or not want...