A Brief History of the Wah Pedal

In a sea of sound effects, one guitar pedal stands out as one of the simplest and most interesting to play, and that one is, of course, the “wah pedal”. Any guitar player who has tried at least one pedal has most likely played the wah-wah.

With almost 50 years of existence, the wah-wah pedals have met soles of the boots of artists like Jimi Hendrix, Slash, George Harrison, Steve Ray Vaughn, Jimmy Page, Kirk Hammet, and even Miles Davis (one of the most incredible trumpeters the world has ever heard). 

But the history of this device, which allows the electric guitar to adopt aspects of the human voice, is a bit complicated. Let’s take a look at the brief history of the wah pedal.


After the Thomas Organ company acquired the rights to distribute the Vox amplifiers, the engineers began working to modify amplifiers to a solid-state by swapping tube circuits for transistors. Then they ran into a switch known as a midrange boost (MRB). The function - a switch that musicians flipped - had been invented by Dick Denney, a British guitarist and engineer.

Thomas Organ was reluctant to install the switch because it would cost $3 per unit. So the company's chief engineer assigned a young colleague, Brad Plunkett, to fix the problem. He accomplished this by replacing the switch with a 75-cent knob, the same as those used to control the volume. 

In 1966 Brad Plunkett came up with the prototype of a pedal mounted inside an organ volume pedal casing. One musician helped him in getting the desired shape in form of the pedal, and that was Del Casher. 

Casher recalls the MRB, which used different frequencies to make sounds louder."I asked, 'What is this knob?' I started turning it and noticed that it made a wah-wah sound as I turned it from left to right. 'Wait, this is what I was looking for!'" But it takes two hands to play the guitar. So Casher claims to have asked Plunkett if the knob could be better integrated into a pedal. Casher and Plunkett, who are mostly credited with the pedal innovation, fine-tuned the new device until it generated its unique sound.


Operating the wah-wah pedal is very simple and it has not changed much since the first brand manufactured it in series (VOX). But the vocal effect that is achieved when connecting an instrument and, above all, the electric guitar, is very interesting. It produces a modulation between the sounds ¨a¨ and ¨ow¨, which alternate as we move the pedal and really seems to say ¨wah-wah¨.

Built from an MRB (Mid-range booster) which is basically a mid-range booster where a potentiometer coupled to the pedal changes the range that will be amplified, giving Wah that characteristic sound, this pedal has added an unparalleled dynamic to the sound used by guitarists, as well as opening up a new range of possibilities for improvisation and increments.


The Wah Wah, as it came to be known, became one of the most popular and important pedals in the history of music, being indispensable to great and important figures. This pedal is even now almost mandatory and is present in the overwhelming majority of guitarist pedal sets around the world. 

In a short time, the Thomas Organ Company purchased the rights to the Vox name and became responsible for the brand right at the time when it was strongly associated with the Beatles. Introduced to guitar stores in 1967, it wasn't until 1969 that the wah-wah pedal rose to fame when Jimi Hendrix wowed the crowd at Woodstock with his guitar sound that he seemed to groan. And that's when the gigantic popularization of Wah Wah began.

How does a wah-wah work?

As for its electronics and its mechanism: it is a mobile pedal on a fixed and heavy base that contains the circuit, and an axis where the pedal pivots back and forth. Connected to the circuit is a potentiometer, which in turn is connected to the movement of the pedal. This potentiometer filters out high, mid, and low frequencies as you move your foot. By moving the tip of the foot forward, we will have a filter for treble and, as we go down towards the heel, we will "comb" frequencies until we have bass only.

Being a pedal with a lot of movement between parts, it tends to loosen and the potentiometer wears out over time. If this happens, it can be changed without problems. Although, I would recommend that someone qualified do it.

The best examples of Wah pedal

  • Jimi Hendrix - Voodoo Child
  • Joe Satriani - Surfing With the Alien
  • Steve Vai - Bad Horsie
  • Black Sabbath - Electric Funeral
  • Led Zeppelin - Dazed and Confused
  • And many more.
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