A 1968 King Vox Wah pedal similar to one that was owned by Jimi Hendrix
The first wah pedal was created by Bradley J. Plunkett at Warwick Electronics Inc./Thomas Organ Company in November 1966. This pedal is the original prototype made from a transistorized MRB (mid-range boost) potentiometer bread-boarded circuit and the housing of a Vox Continental Organ volume pedal. The concept, however, was not new. Country guitar virtuoso Chet Atkins had used a similar, self-designed device on his late 1950s recordings of "Hot Toddy" and "Slinkey". Jazz guitarist Peter Van Wood had a modified Hammond organ expression
pedal; he recorded in 1955 a version of George Gershwin's "Summertime" with a "crying" tone, and other recordings including humorous "novelty" effects. A DeArmond Tone and Volume pedal was used in the early 1960s by Big Jim Sullivan, notably in some
Krew Cats instrumental tracks, and in Dave Berry's song "The Crying Game".
The creation of the modern wah pedal was an accident which stemmed from the redesign of the Vox Super Beatle guitar amplifier in 1966. Warwick Electronics Inc. also owned Thomas Organ Company and had earlier entered into an agreement with Jennings Musical Instruments (JMI) of England for Thomas to distribute the Vox name and products in the United States. In addition to distributing the British-made Vox amplifiers, the Thomas Organ Company also designed and manufactured much of the Vox equipment sold in the US The more highly regarded British Vox amplifiers were designed by Dick Denney and made by JMI, the parent company of Vox. Warwick assigned Thomas Organ Company to create a new product line of solid state Vox amplifiers called Vox Amplifonic Orchestra, which included the Super Beatle amplifier, named to capitalize on the Vox brand name's popularity in association with the Beatles, who used the JMI English Vox amplifiers such as the famous Vox AC30 (although the Beatles did use several American-made Super Beatle units on their 1966 US tour). The US-made Vox product line development was headed by musician and bandleader Bill Page. While creating the Vox Amplifonic Orchestra, the Thomas Organ Company decided to create an American-made equivalent of the British Vox amplifier but with transistorized (solid state) circuits, rather than vacuum tubes, which would be less expensive to manufacture. During the re-design of the USA Vox amplifier, Stan Cuttler, head engineer of Thomas Organ Company, assigned Brad Plunkett, a junior electronics engineer, to replace the expensive Jennings 3-position MRB circuit switch with a transistorized solid state MRB circuit.
Plunkett had lifted and bread-boarded a transistorized tone-circuit from the Thomas Organ (an electric solid state transistorized organ) to duplicate the Jennings 3-position circuit. After adjusting and testing the amplifier with an electronic oscillator and oscilloscope, Plunkett connected the output to the speaker and tested the circuit audibly. At that point, several engineers and technical consultants, including Bill Page and Del Casher, noticed the sound effect caused by the circuit. Page insisted on testing this bread-boarded circuit while he played his saxophone through an amplifier. John Glennon, an assistant junior electronics engineer with the Thomas Organ Company, was summoned to bring a volume control pedal which was used in the Vox Continental Organ so that the transistorized MRB potentiometer bread-boarded circuit could be installed in the pedal's housing. After the installation, Page began playing his saxophone through the pedal and had asked Joe Banaron, CEO of Warwick Electronics Inc./Thomas Organ Company, to listen to the effect. At this point the first electric guitar was plugged into the prototype wah pedal by guitarist Del Casher who suggested to Joe Banaron that this was a guitar effects pedal rather than a wind instrument effects pedal. Banaron, being a fan of the big band style of music, was interested in marketing the wah pedal for wind instruments as suggested by Page rather than for the electric guitar as suggested by Casher. After a remark by Casher to Banaron regarding the Harmon mute style of trumpet playing in the famous recording of "Sugar Blues" from the 1930s, Banaron decided to market the wah-wah pedal using Clyde McCoy's name for endorsement.
After the invention of the wah pedal, the prototype was modified by Casher and Plunkett to better accommodate the harmonic qualities of the electric guitar. However, since Vox had no intention of marketing the wah pedal for electric guitar players, the prototype wah-wah pedal was given to Del Casher for performances at Vox press conferences and film scores for Universal Pictures. The un-modified version of the Vox wah pedal was released to the public in February 1967 with an image of Clyde McCoy on the bottom of the pedal.
Warwick Electronics Inc. assigned Lester L. Kushner, an engineer with the Thomas Organ Company, and Brad Plunkett to write and submit the documentation for the wah-wah pedal U.S. Patent 3,530,224 ("foot-controlled continuously variable preference circuit for musical instruments") on September 22, 1970.
Early versions of the Clyde McCoy featured an image of McCoy on the bottom panel, which soon gave way to only his signature. Thomas Organ then wanted the effect branded as their own for the American market, changing it to Cry Baby which was sold in parallel to the Italian Vox V846. Thomas Organ's failure to trademark the Cry Baby name soon led to the market being flooded with Cry Baby imitations from various parts of the world, including Italy, where all of the original Vox and Cry Babys were made. Jen, who had been responsible for the manufacture of Thomas Organ and Vox wah pedals, also made rebranded pedals for companies such as Fender and Gretsch and under their own Jen brand. When Thomas Organ moved production completely to Sepulveda, California and Chicago, Illinois these Italian models continued to be made and are among the more collectible wah pedals today.