🎺 In October 1965, Vox designer Dick Denney traveled to Thomas Organ Company—the American distributor for Vox—to consult on a new line of transistor amplifiers. One of them, the 100-watt Vox Super Beatle, had a resonant boost. And Denney noticed something: switching between the boost’s two positions produced an interesting "wah-wah" effect.
In a memo, Denney wrote: "An interesting wah-wah effect occurs when toggling the boost switch between two positions. Remote control from the guitar would be groundbreaking, though cost and complexity will likely be high."
That memo was the beginning of one of rock’s most iconic effects. And its inventors didn’t even realize what they’d created.
⚙️ Engineer Brad Plunkett at Thomas Organ took up the task. He replaced the switch with a potentiometer and used an Armstrong oscillator circuit suggested by colleague Les Kushner. Plunkett tested the effect with guitarist friend John Glenum—both were thrilled. But manually adjusting the potentiometer proved impractical.
Here, the stories diverge. Both Plunkett and Vox session guitarist Del Casher claim they were the first to suggest using a Vox organ pedal instead of manual control. Casher recalled that Thomas Organ president Joe Benaron heard the effect and declared: "Unsuitable for electric guitar."
But for trumpet? Fine.
💰 The twist that makes this story truly ironic: the original resonant boost circuit by Stan Cutler was designed to mimic the sound of a trumpet with a harmon mute—the signature tone of jazz trumpeter Clyde McCoy.
McCoy was paid $500 for the rights to use his name. The first Vox wah-wah pedals, released in August 1967, featured his photo on the bottom plate. McCoy never once used the pedal. He was a trumpeter.
A pedal for trumpet. Named after a trumpeter. Who never played it.
🎸 Guitarists started using the wah-wah almost immediately, despite Benaron’s insistence it was "unsuitable." Del Casher was the first to record the wah-wah with a guitar—and quickly realized the effect sounded incredible on electric guitar. Frank Zappa added it to his arsenal by 1967. Jimi Hendrix made the wah-wah an essential part of his sound—"Voodoo Child (Slight Return)" without it is unthinkable.
Eric Clapton used it in Cream. Isaac Hayes turned the wah-wah into the calling card of funk in "Theme from Shaft" (1971). David Gilmour—in Pink Floyd solos. Kirk Hammett—in every other Metallica solo.
An effect for trumpet became the voice of the electric guitar. For good.
🔊 The essence of the wah-wah is a resonant bandpass filter that "slides" across frequencies when the pedal is pressed. Low pedal position—bass frequencies. High position—treble. The result is a sound resembling vowels: "waaa-ooo." That’s why the effect sounds "human"—it mimics what the oral cavity does when forming speech.
The Armstrong oscillator creates a resonant "peak" at a specific frequency. The potentiometer shifts that peak. The result? The guitar "talks."
The story of the wah-wah is about how a tool doesn’t know what it’s made for. The Vox Super Beatle was an amp for beat music. The resonant boost was meant to imitate a trumpet. The switch between modes—a technical detail. But when someone started toggling that switch in real time, a new sound was born—one no one planned.
McCoy got $500. Casher and Plunkett fought over credit. Vox sold millions of pedals. And Hendrix, Clapton, Zappa, and Hammett made the wah-wah the voice of the electric guitar forever.
A pedal for trumpet. That a trumpeter never used. But changed the sound of rock.