Del Casher, the guitarist who invented the wah-wah pedal that transformed the sound of classic rock, has died. He was 88.

Casher died Oct. 1 after battling cancer, according to a GoFundMe account posted Oct. 29 by family friends to support his widow.

Born Delton Kacher in Indiana, the guitarist played with the famed session ensemble the Wrecking Crew. He performed with Gene Autry and Lawrence Welk, and appeared on screen with Elvis Presley in the musical film “Roustabout” and Jerry Lewis in comedy film “The Patsy.”

While tinkering with new electronics to innovate his sound in the late ‘60s, he had the idea for a pedal that could alter the instrument’s EQ frequencies mid-performance. Along with engineer Brad Plunkett, he developed the first “Cry Baby” pedal with the Thomas Organ Co.…