Vox Grey Wah vs. Clyde McCoy Wah

[Paul Marossy]

I just read a claim where the Vox grey wah predates the Clyde McCoy. Does anyone know if this is true? I do know that the Vox grey wah had a 100K resistor to ground parallel with inductor, an absence of the 33K resistor in parallel with inductor (no resistor at all!) and a inductor that measured 250-300mH.

How does the sound compare with the Clyde McCoy, more trebly or less trebly? Anyone have any experience with those old grey Vox wahs? I'm asking because I'd like to build the circuit for fun to see what it sounds like and how it can be tweaked...

[Pedal love]

I don't know much about them except the ones that were used by the likes of Hendrix and Clapton, were the McCoys. The greys had a long tag board, with mostly axial leaded components.pl

[Paul Marossy]

Yeah, I've got pictures of one. If it is pre-Clyde McCoy, then that would probably be the very original version of the Vox wah pedal before it was patented. It seems like info on this beast is kind of scarce...

[1wahfreak]

From an informed wah person;

According to various books, Thomas sent a
prototype circuit over for JMI to copy, and Denney started making them in
his garden shed (?), using volume pedal housings. They wanted to get some
wahs out on the street and they didn't want to wait for the Italian wahs to
come on stream. Denney's wife helped him out, apparently no mean assembler
herself.


The one I had sounded like crap. I basically sounded like a treable sweep. Almost no vocal "wah" personality. Hers's something from the same wah expert;

Yours sounds normal, based on my limited experience.
I've got two of the later ones without the epoxy on the board, and they're
pretty weak unless they're run into a fuzz box - then they nail the early
Jimmy Page sound. Not much use with a clean tone though...

The inductors in the grey wahs are much lower in inductance than most other
wahs (the JMI factory schematic backs this up), which results in a higher
sweep range. Also, the pot is usually a log pot, rather than the special
taper used in later wahs. Using a log pot means a large proportion of the
sweep will be in the treble region, which exacerbates the effect of the
inductor, and it's only because these pedals have a long throw that you get
any low frequencies at all.

It's possible to extend the bass end of the sweep by boosting the gain, but
since you can't remove the board, it's hard to see how you'd do this.
Replacing the emitter resistor on Q1 is out of the question, so you'd have
to replace Q1 with a higher gain device, or solder a lower value resistor
across the emitter resistor. Your best bet might be to accept it as-is,
and/or sell it as a collector's item.


I couldn't remove the board in mine because it was covered in goo. I did end up selling it a while later for $700.00. If it really did predate the Clydes, it had the ealiest serial number that any one knows of.....damn!!   

[Paul Marossy]

Thanks for the insight on this one 1wahfreak! It's funny how people will pay $700-1200 for a wah that doesn't even sound that good. 

I'm still going to build it just for fun, though.

[Paul Marossy]

Anyone ever measure the inductance/DC resistance on one of these grey wahs? 

[leonhendrix]

Ive been told the inductance is 250mH, i was intrested in finding this pedal until one sold for £700+ on ebay, I think there is one on there now without the original inductor.

leon