Cassidy died Dec. 6 in San Jose, Calif., reports The New York Times. The newspaper says his former wife Beverley Cassidy said the drummer succumbed to cancer.

Already a veteran musician when Spirit formed in 1967, Cassidy’s stepson, Randy Wolfe, was the band’s guitarist. Wolfe was dubbed “Randy California” by Jimi Hendrix after the two had met in a New York City music store. Wolfe drowned in 1997 in Hawaii.

Spirit’s biggest hit was the 1968 single “I’ve Got A Line On You.” Nicknamed “Mr. Skin” because of his shaved head, the moniker was also the name of the band’s 1970 hit.

Bob Irwin, whose Sundazed Records has reissued several Spirit albums said Cassidy always drove the band to push the envelope.

“Ed always encouraged them to color outside the box, to take chances onstage, to play to the best of and beyond their abilities,” Irwin said.