WASHINGTON — Gary Duncan, a guitarist and singer for Quicksilver Messenger Service, an electrifying mainstay of the San Francisco psychedelic scene that rivaled Jefferson Airplane and the Grateful Dead in the late 1960s, died Saturday. He was 72.
His friend Rusty Goldman, a self-described ‘‘San Francisco scenester’’ and ’60s rock archivist known as Professor Poster, said Mr. Duncan had gone into a coma; he was not sure precisely where he died. Mr. Duncan’s band also confirmed the death in a Facebook post but did not provide additional information.
Formed in California in 1965, Quicksilver Messenger Service helped create the ‘‘San Francisco sound,’’ fusing rock, blues, folk, and jazz in a blend that made them a staple of venues such as the Fillmore, Avalon Ballroom, and California Hall, where the air was filled with the smells of incense, marijuana, and patchouli during performances.
‘‘You listen to these records and they take you back to a simpler time,’’ Goldman said in a phone interview. ‘‘Their music was pure. Everyone always left their shows feeling high on the music as well as whatever else they ingested.’’
Mr. Duncan was not yet 20 when he joined Quicksilver Messenger Service and began making loose, heavily improvised music with drummer Greg Elmore, bassist David Freiberg, and fellow guitarist John Cipollina, with whom he developed a complex, vibrato- and reverb-heavy interplay.
For a time, the band also featured guitarist Jim Murray and songwriter Chet Powers (known by his stage name Dino Valenti), a Greenwich Village folk singer who had written the peace anthem ‘‘Get Together’’ before being busted on drug charges that kept him from performing with Quicksilver Messenger Service in its early years.
Known for its brilliant, drug-infused live performances, the band initially resisted following peers such as Jefferson Airplane into the recording studio. ‘‘We had no ambition toward making records,’’ Mr. Duncan once said, according to the website Best Classic Bands. ‘‘We just wanted to have fun, play music and make enough money to be able to afford to smoke pot.’’
But after 1967 performances at the Human Be-In and the Monterey Pop Festival, where they took the stage alongside acts including Jimi Hendrix, The Who, and Jefferson Airplane, Quicksilver Messenger Service landed a contract with Capitol Records, resulting in their self-titled debut the next year.
Generally considered their finest studio effort, the record opened with a cover of Hamilton Camp’s ‘‘Pride of Man’’ — ‘‘Oh God, pride of man, broken in the dust again!’’ — and included ‘‘Gold and Silver,’’ a rock reworking of Dave Brubeck’s ‘‘Take Five,’’ cowritten by Mr. Duncan.
Their follow-up, ‘‘Happy Trails’’ (1969), was described by Rolling Stone as ‘‘the definitive live recording of the late-Sixties ballroom experience,’’ and ranked No. 189 on the magazine’s list of the 500 greatest albums. Featuring extended jams built around the Bo Diddley songs ‘‘Who Do You Love?’’ and ‘‘Mona,’’ as well as Mr. Duncan’s compositions including ‘‘Cavalry,’’ it showed ‘‘that psychedelia was about more than just tripping out,’’ Rolling Stone wrote.
Offstage, band members lived at ‘‘a commune in Marin County where all manner of musicians, old ladies with babies, dope dealers and human driftwood coalesced into a barely functioning whole,’’ according to ‘‘A Perfect Haze,’’ a history of the Monterey Pop Festival by Harvey and Kenneth Kubernik.
After the release of ‘‘Happy Trails,’’ Mr. Duncan left the group for about a year — in part because of drug use, Freiberg said — and then returned to record ‘‘Just for Love’’ (1970). The album included Quicksilver Messenger Service’s only single to reach the Top 50, ‘‘Fresh Air,’’ as well as a fresh-from-prison Valenti, who took over lead vocals after Mr. Duncan and his bandmates had taken turns at the mic.
Mr. Duncan played on subsequent albums before the group disbanded after the release of ‘‘Solid Silver’’ (1975). He revived the Quicksilver name in the late 1980s and in recent years toured with Freiberg, who also performed with Jefferson Airplane and Jefferson Starship, groups whose popularity had long ago eclipsed that of Quicksilver Messenger Service.
By most accounts, Mr. Duncan was born Gary Grubb in San Diego on Sept. 4, 1946, and was raised in Ceres, Calif. He gave few details on his upbringing but said he was a Native American orphan who ‘‘grew up with rednecks,’’ built and fixed cars, worked at canneries, served in the military, and spent a year in prison for marijuana possession before launching his music career.