Amp Crazy .Com
Hollywood, California
"The Original Since 1978"

Wah Modifications

Mods For Vox & Cry Baby Wah Pedals

As Used By
...and others

Amp Crazy
V846 Custom Wahs
click here


30% Boost with
A-B switch

Pre-set Freq Control
with select switch

True Bypass Switch

LED Indicator
with silent switching





  How it all started 

When I was still actively playing back in late 70's, I noticed that my stock Thomas-Organ
Cry Baby Wah... worked... but sounded a bit thin, even with a Les Paul cranked through a Marshall Stack or Super Reverb.

And when the effect was turned on... there was a drop in the overall volume as the pedal swept over the frequency ranges.

I also wanted to get that Brian May "Midrange Tone" for solos.  The pedal could sort of get it, but, the solo was often over, before you could dial in just the right sweet spot that you were looking for.

After studying the circuit a bit, and doing some experimentation, I finally found just the right combination of circuit changes to give me the perfect wah sound that I was searching for.

The mod gave the pedal a fuller... fatter sound... that actually jumped out when you activated
the effect.  Besides a better tone, it also had a bit of a growl & lead boost effect.  And, the Brian May Sound was there, better than ever, but... there was still the problem of finding that sound during a solo.

There was always the Michael Schenker trick of using two Wahs.  One would be set stock and used as a regular Wah.  The second one... he would disconnect the gear arm and reach in and pre-set the control with his finger to exactly the spot that he wanted.  When the second Wah was activated, it came on at his pre-set control point.

But... that required Two Wahs...
So, instead, I added a second control with a built-in switch to the right side of the wah chassis.
In the switch OFF position I had a standard Wah-Wah with my new Boost.  With the switch in the ON position... the wah sweep pedal was deactivated... and the boosted sound could be dialed in with the added new control to exactly the frequency that I wanted.

This Boost is really meant for Rock & Roll... it is a bit aggressive.  As you hit the string harder, more growl is produced.  I found that for Clean - Funky... Ohio Players' style... 9th Rhythm Chords, that I had to reduce the guitar volume a bit to get it to be "clean and funky" enough.

So... I added an A-B switch to select either Boosted Wah or Normal Wah.  I had the best of all worlds... Rockin' Boosted Wah... or Funky Normal Wah... and either sound with a Pre-Settable Frequency Control.

In the late 70's I turned the original Wah Boost into a DIY Packaged Kit, and sold them in Guitar Player Magazine and through a few dealers in the USA and Europe.  A bit later, I also added Kits For Amps.  There were a dozen different kits for wahs and amps.  By the early 1980's the kits were discontinued... they are no longer available.

When people would come to our Hollywood shop, I would demonstrate and let them test out my original Cry Baby pedal that was done in the 70s's.

  "You could hear a huge the flip of a switch" 

Guns & Roses, Zakk, Schenker, Prince and others... all had this mod done. (Prince originally borrowed Jesse Johnson's modded pedal for the "1999" Album...and later on, he gave me a ColorSound Wah Pedal to gut, and install a 70's Vox-Thomas circuit with 30% Boost and LED).


  Boosting Your Wah 

This Boost is specifically designed for the Original 60's & 70's Vox Wah, King Vox Wah
and Thomas-Organ Cry Baby Wah-Wah Pedals.

  • It can also be installed in the reissue Vox Wah and Dunlop "Original" Cry Baby
    Wah-Wah circuits with two transistors.

  • Some of the newer Dunlop "Original" Cry Baby Wahs have 3 transistors. Those
    models can also be modified, but may require additional labor.

  • Some of the newer Boutique Wah Pedals that are copying the original 60's circuits
    may also be modified.  It will depend on the particular circuit.  I recently modified a
    Budda Wah that turned out well.

The Wah to be modified should be in good general working order.  Bad pots, jacks, footswitches or other stock operational parts needed... are extra.

Wahs by companies like Morley, Mutron, Roland, Boss, Foxx... and, some of the newer Dunlop "Specialty Wahs" cannot be modified.  Contact us if you have any questions.

The Basic Boost has always been titled "30% Boost" ...because that was what it seemed to sound like when I first played it back in 1977.  I have never really measured the actual amount of signal level increase.  I suspect it to be 10 - 15 db or more. There is a definite tonal improvement, ..fatter.. with more sweep and growl... louder signal... the effect output level is boosted, as you would normally want it to be.

This will let you select the 30% Boost or the original normal sound.  A small mini-toggle switch is mounted under the sweep pedal at the top right part of the chassis.  You can select either mode before activating the effect.  Some people request the A-B Switch to be footswitchable.  This is not possible.  A loud pop would be heard when A-B switching... if the effect were in the active mode.

Cost for installing the 30% Boost with A-B Switch is $125.00

The "Pre-Set Frequency Control with wah-preset switch" is a separate modification from the boost mod, and can be added to a stock or boosted wah of any era.  This would include a separate control for the pre-set sound, and a separate mini-toggle switch mounted under the sweep pedal at the top right part of the chassis, to select the Wah or Preset Mode.

Cost for installing the Pre-Set Frequency Control with switch is $125.00
(This is for the Pre-Set only...and does not include the 30% Boost)

With a stock Vox, Thomas Organ, or Dunlop Wah, the instrument signal is always connected to the input of the wah circuit, even when the effect is turned off.  This will slightly reduce the highs and  normal "straight" signal level, and, would be even more noticeable if long standard cables are used.  We can rewire the circuit and install a heavy duty DPDT to eliminate this problem.  With the effect in the off position, the circuit would be completely bypassed and produce a louder straight signal with better highs.

Cost for installing the True Bypass Switch is $100.00

Some people request that an LED indicator be installed to show when the wah effect is on.  Unfortunately, when this is done by installing a simple passive footswitch there is a loud annoying pop that occurs when the wah circuit and LED are activated.  In order to eliminate this problem, an additional LED switching circuit must be created and installed in addition to replacing the original footswitch.  This is a time consuming modification, but, can be done to boosted or stock wahs with a choice of LED colors.

Cost for installing the LED Indicator With Silent Switching is $150.00


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