Jefferson Airplane co-founder Marty Balin has died at the age of 76.
The guitarist and singer, who co-founded the San Francisco psychedelic rock band in 1965, co-wrote five songs on the band's breakthrough LP Surrealistic Pillow.
His tenor voice became a key component of Jefferson Airplane's signature sound.
Mr Balin was brutally beaten by the Hells Angels at the infamous Altamont festival in 1969, after he dived into the audience to help an audience member.
He died this week with his wife, Susan Joy Balin, by his side, spokesperson Ryan Romenesko said in a statement. The cause of death was not announced.
Jefferson Starship, the splinter band that Balin also played in for a number of years, paid tribute to their former band-mate on its official Facebook site.
"With heavy hearts, we learn today of the passing of Marty Balin. He was a true talent and inspiration to many. We send his family and friends our deepest condolences."
Mr Balin teamed up with guitar player Paul Kantner in San Francisco and the band launched its debut album, "Jefferson Airplane Takes Off," in 1966. Kantner died in 2016.
The band was best known for the hits sung by vocalist Grace Slick, including "Somebody to Love," and "White Rabbit".
They played at Woodstock music festival in 1969 and were inducted into the Rock and Roll Hall of Fame in 1996.
Mr Balin wrote songs including "Volunteers" and "Today" for the band, as well as contributing to hits for Jefferson Starship, including "Runaway" and "Miracles."
The band went through various line-ups, and Mr Balin left Jefferson Starship in 2008 to focus on a solo career.
He had heart surgery in 2016 and in August this year he filed a civil lawsuit for malpractice against a New York City hospital, saying he left the hospital with a damaged tongue and vocal chords.
"We were all touched by his love," Susan Joy Balin said in a statement.
"His presence will be within my entire being forever."