Ray Collins, a singer who co-founded the Mothers of Invention with Frank Zappa but left when "too much comedy" started appearing in the band's songs, died on Monday at a California hospital. He was 75.

The Claremont, Calif. resident had been at Pomona Valley Hospital since suffering a massive heart attack on Dec. 18, according to the Inland Valley Daily Bulletin. Doctors took him off life support on Saturday.

Collins is responsible for hiring Zappa in 1964 to play guitar for his bar band the Soul Giants, which in short order morphed into the Mothers. Record producer Tom Wilson signed the group to Verve Records and by the time debut album "Freak Out!" emerged in 1966 the band added "of Invention" to their name and Zappa had become the creative leader.

Collins sings lead on much of the avant-garde classic, a double set that includes the single "Who Are the Brain Police?" as well as "Hungry Freaks, Daddy" and the 12-minute "The Return of the Son of Monster Magnet."

The album, which did not sell well but holds cult classic status, was honored with a Grammy Hall of Fame Award in 1999.

Collins stayed on with the band for 1967's "Absolutely Free" before dropping out before the recording of followup "We're in It for the Money" in 1968. He came back later that year to provide the falsetto parts in the Mothers' doo-wop concept album, "Cruising With Ruben & the Jets" before leaving again out of creative differences with Zappa, who died in 1993.

"Too much comedy, too much making fun of stuff," Collins said in an interview with the Daily Bulletin. "I just wanted to make beautiful music. I was raised on Johnny Mathis and Nat King Cole."

Instead Collins retired from music, living what has been described as an "aimless existence" in the following decades, working as a taxi driver, a dish washer and living out of a van for a number of years. His only income came from songwriting royalties and Social Security.