Mr. Braunn, who was born in Pekin, Ill., and raised in Los Angeles, was a violin prodigy who began his musical career at 4. He joined the heavy-metal band Iron Butterfly when he was 16 and toured with it from 1967 to 1969, when the group was enjoying its greatest success.
Mr. Braunn, Doug Ingle, Ron Bushy and Lee Dorman left their mark on musical history with the psychedelic "In-a-Gadda-da-Vida," released in 1968.
It went platinum and stayed on the national sales chart for two years; a three-minute version became a Top 40 radio hit.
Mr. Braunn occasionally reunited with the band for performances and worked as a songwriter, musician and producer until his death.
During a 1988 reunion he told The Los Angeles Times about his experience with stardom decades earlier: "My first vacation I bought a car, a Jaguar, and parked it outside the hospital where I spent two weeks for ulcers and gastroenteritis."