Modding Vox Wahs

[Progrockabuse]

hey peeps, i have a vox wah. mainly brought as i wanted to go after that more rounded vocal like wah sound. since owning it i've found that the vox is quite shrill and seems to have limited travel. i've tried the old moving the cog back inside to change the travel, but can't find a nice balance.

anyone modded one of these before? if i could i'd love to mod it so it has a q control like the dunlop wahs (i'd love the jerry cantrell one)

[Rhysyrhys]

I always found this guy (click DIY resources) useful over the years. I have a Vox too and like to fuck around with that, most recently using it as a bass wah. Sounds bloody fantastic to my ears because I wanted a more Omar Rodriguez sound than a growly tobacco-ey wah sound that is the archetypal Vox honk, so with the bass wah mod I was getting close to the Cygnus Vismund... Cygnus and Rapidfire Tollbooth sounds that I love. It took a few cap changes to get what I wanted but I think I settled with 0.054uF (might be wrong value there, been a while since I did it).

[SGJarrod]

i'd love the jerry cantrell one

I do not understand how we think so much alike on gear

I modded my Crybaby but have no help on the VOX

[Progrockabuse]

we gotta make it a life plan to jam one day SGJ.

might just sell the vox and get a jerry.

[SGJarrod]

the Jerry is not too different from the regular CryBaby with the Q..... the only change is some resistors and caps to make it darker and more vocal like....

I just have the reg CryBaby and did the normal resistor/cap mods and put in a red fasel inductor and it made all the difference in the world.... it is very vocal and Fat now, it sings on single note runs....

check out this site under the Guitar FX section...he has tons of mods and info on Wah's...

DIY Guitarist

this is a great all around guitarist site..... Paul is a very helpful and stand up dude too

[SGJarrod]

here is a Vox Wah mod/info page http://stinkfoot.se/archives/561

can use this project info to mod urs.. http://fuzzcentral.ssguitar.com/axiswah.php

Stock Vox Wah Scheme

I'll add more to this post if I find them..

[Will]

I've found putting in lower-gain transistors helps quite a bit. I think I put BC108s in mine.

[Mages]

I've found putting in lower-gain transistors helps quite a bit. I think I put BC108s in mine.

this. the transisters they put in there now gain the hell out of the circuit and makes it behave in strange ways. I used BC108Cs in mine and they worked great. although you might try swapping just one out and leaving one of the stock ones.

here is mine:

[SGJarrod]

yarp....


from one of the links I provided....


Changing the Transistors
The transistors that come in the Vox V847 and Dunlop Crybaby pedals are the high gain, general purpose MPSA18. I personally think that these transistors are way too high gain to make a good sounding wah pedal. The toe-down position is quite ear-piercing and unpleasent. To help make a more mellow wah pedal, I've chosen to use a pair of nice BC109C transistors that I ordered from Steve Daniels of Small Bear Electronics a while back. For Q1 I chose a unit with a gain of 400, and for Q2 I chose one with a gain of 388. The end result was a very nice, a bit more mellow sounding wah that's not as ear-piercing when toe-down, and the heel-down is still nice and fat...the bass response actually made the springs in my Twin Amp's tube shields rattle!

[Bill Oakley]

Try changing only Q1. Leave Q2 alone. Q2 is an emitter follower. If the hfe is higher input resistance is higher. The transistor is also biased via a 470k from the first transistors collector. The higher the hfe, the lower the voltage drop across the 470k because less base current is needed. Last, a higher hfe will mean less loading of the pot and Q1's collector. So you would want Q2 to have a high hfe.

Using a trasistor with a lower hfe for Q1 should result in a fatter sound.

Just my 2 cents.