Sam Andrew was playing guitar with the San Francisco rock band Big Brother and the Holding Company in 1966 when the group’s manager brought an unknown singer to a rehearsal.

“She walked in one day and started singing some songs,” Andrew said in a 2012 Music- Radar interview. “I thought, ‘Wow!’ ”

The singer was Janis Joplin, whose explosive, emotionally raw performances propelled the band to worldwide fame that turned out to be short-lived.

Andrew, 73, whose tempestuous relationship with Joplin included writing songs for her and a love affair, died Feb. 12 at UCSF Medical Center in San Francisco.

He had a heart attack in early December and suffered numerous complications, said his wife, Elise Piliwale.

In addition to playing guitar, Andrew sang and wrote songs, including “Combination of the Two” which was performed during the band’s breakout performance at the 1967 Monterey Pop Festival and featured in several films, including 1998’s “Fear and Loathing in Las Vegas.”

And he arranged the band’s version of “Summertime,” from “Porgy and Bess,” on which Joplin famously wailed.

Andrew was a founder of the band in 1965 that largely played unstructured jam sessions in its early performances, with set pieces including a rock version of classical composer Edvard Grieg’s “In the Hall of the Mountain King.”

When Joplin joined the band, the group became more organized and focused on her singing, which became more dramatic. “She learned how to be an electric singer,” Andrew told the MusicRadar site. “We played so loud that she had to compete, so that’s when she started screaming.”

Andrew, who mostly played rhythm guitar in Big Brother, also evolved. “I think he developed quite a lot as a guitar player,” Dave Getz, the group’s drummer, said in an interview Tuesday. “He started to emerge as another lead guitar player in the band.”

The band was mostly a local sensation in San Francisco until the Monterey festival, which also featured The Who, Otis Redding and Jimi Hendrix. Even in that company, Big Brother with Joplin out front was such a standout that the group was asked to do a second performance so it could be filmed for the “Monterey Pop” documentary directed by D.A. Pennebaker.

Joplin became a star and the 1968 Big Brother album “Cheap Thrills,” including “Summertime,” was No. 1 on the Billboard album chart for eight weeks. Although Joplin got rave reviews for the album, the band didn’t fare as well with critics. That same year, she announced she was leaving Big Brother.

Andrew went with her, joining her new group, the Kozmic Blues Band. It was a move he later regretted. “That was one thing I wish I had the chance to do over,” he told Goldmine magazine in 2012.

He and Joplin were doing a lot of drugs, including heroin, sometimes together. In less than a year, she fired him from the new band. Then for a time, they became lovers.

“Probably something inside of me said, ‘Well, now she’s fired me so we can have this relationship,’ ” he said in a 2007 Kansas City Star interview. “It was very brief but very sweet.”

Joplin died in 1970 in a Hollywood motel of a drug overdose. She was 27.

Andrew, Getz and other members of Big Brother eventually re-formed the band. They toured on and off, often in Europe, over the years, but never again had a singer that gave the group mass acclaim.

“I think we had 30 to 40 different singers,” Getz said.

Andrew was born Dec. 18, 1941, in Taft, California. As an Air Force brat, he lived in many places while growing up including Okinawa, Japan, where he attended high school. He went to several universities, including the Sorbonne in Paris, but did not get a degree.

In addition to touring with the band in his later years, he was musical director of the off-Broadway and touring show “Love, Janis,” about the life of Joplin.

“I’m in the Janis Joplin business,” he said in 2006.