SAN JOSE, Calif. — Jerry Miller, a founding member of the pioneering ’60s San Francisco psychedelic rock band Moby Grape, died July 20 in Tacoma, Washington.

Miller had just turned 81 earlier this month. The cause of death was not immediately available.

News of his passing was posted on social media channels — including on a Moby Grape Facebook fan page — and circulated via multiple news outlets.

Miller will be remembered as a guitarist’s guitarist, boosting a fan base that includes some of the finest fret men in popular music history. Many of these admirers are Rock & Roll Hall of Famers, including Jimmy Page of Led Zeppelin, Jerry Garcia of the Grateful Dead and Eric Clapton.

It’s the latter who reportedly once referred to Miller as the “best guitar player in the world.” That’s incredibly high praise coming from the only three-time inductee to the Rock Hall as well as a man who himself is routinely rated among the best guitarists of all time.

Miller would showcase that guitar work with aplomb and impact on Moby Grape’s 1967 debut, which reached as high as No. 24 on the album charts and positioned the group as one of the key acts in the burgeoning “San Francisco Sound” movement of the era. In comparison, the debut album from the Grateful Dead — one of Moby Grape’s key contemporaries on the ’60s Bay Area scene — only climbed to No. 73 upon being released that same year.

Unlike the Grateful Dead, however, Moby Grape only managed to stay together for a relatively short time during its initial go-around. They formed in 1966 — bringing together such experienced players as Skip Spence from Jefferson Airplane and Peter Lewis of the Cornells — and originally called it quits by 1969. During that time span, however, the group released four studio albums: 1967’s “Moby Grape" and 1968’s “Wow/Grape Jam” as well “Moby Grape ’69” and “Truly Fine Citizen,” both from 1969.

The first album was a stone-cold classic, one that is still cherished to this day by fans of heavy-duty psychedelic/blues/acid rock. Indeed, the record — which featured a group shot on the cover by legendary Bay Area rock photographer Jim Marshall — came in at No. 121 on Rolling Stone’s “500 Greatest Albums of All Time” list in 2003, more than 35 years after “Moby Grape” was released.

Miller’s guitar work was a huge factor in what made that first album so special, taking the captain’s chair — alongside Skip Spence and Peter Lewis — in a three-guitar attack that still sounds so powerful to this day.

“Wow/Grape Jam” was another success for the band, reaching as high as No. 20, but the two discs that followed were commercial disappointments and failed to even crack the top 100. As the gas tank began to run dry on the ’60s — and a legal battle with their former manager heated up — the storyline had changed from high hopes to “what could’ve been” for Moby Grape. The band folded in 1969, but would regroup several times over the decades.

“The Grape’s saga is one of squandered potential, absurdly misguided decisions, bad luck, blunders and excruciating heartbreak, all set to the tune of some of the greatest rock and roll ever to emerge from San Francisco,” music historian Jeff Tamarkin wrote. “Moby Grape could have had it all, but they ended up with nothing, and less.”

Born in Tacoma, Wash., on July 10, 1943, Miller began playing in bands in the ’50s and would find some success as a member of the Frantics. In 1966, the Pacific Northwest rock outfit headed south to San Francisco — where a music revolution was blooming — and its nucleus went on to help form Moby Grape.

Besides playing with Moby Grape, the acclaimed guitarist — who also sang — performed with the Santa Cruz act known as the Rhythm Dukes and well as his own Jerry Miller Band.

There has been no word yet on any possible public memorial services.