If musicians were measured not by the number of records they sold but by the number of peers they influenced, JJ Cale would have been a towering figure in 1970s rock 'n' roll. His best songs like "After Midnight," ''Cocaine" and "Call Me the Breeze" were towering hits â€” for other artists. Eric Clapton took "After Midnight" and "Cocaine" and turned them into the kind of hard-party anthems that defined rock for a long period of time. And Lynyrd Skynyrd took the easy-shuffling "Breeze" and supercharged it with a three-guitar attack that made it a hit. Cale, the singer-songwriter and producer known as the main architect of the Tulsa Sound, passed away Friday night at Scripps Hospital in La Jolla, Calif. His manager, Mike Kappus, said Cale died of a heart attack. He was 74. While his best known songs remain in heavy rotation on the radio nearly 40 years later, most folks wouldn't be able to name Cale as their author. That was a role he had no problem with. "No, it doesn't bother me," Cale said with a laugh in an interview posted on his website. "What's really nice is when you get a check in the mail." And the checks rolled in for decades. The list of artists who covered his music or cite him as a direct influence reads like a who's who of the Rock and Roll Hall of Fame â€” Clapton, Neil Young, Tom Petty, Johnny Cash, Mark Knopfler, The Allman Brothers, Carlos Santana, Captain Beefheart and Bryan Ferry among many others. Young said in Jimmy McDonough's biography "Shakey" that Cale and Jimi Hendrix were the best guitar players he had ever heard. And in his recent memoir "Waging Heavy Peace," Young said Cale's "Crazy Mama" â€” his biggest hit, rising to No. 22 on the Billboard singles chart â€” was one of the five songs that most influenced him as a songwriter: "The song is true, simple, and direct, and the delivery is very natural. JJ's guitar playing is a huge influence on me. His touch is unspeakable." It was Clapton who forged the closest relationship with Cale. They were in sync musically and personally. Clapton also recorded Cale songs "Travelin' Light" and "I'll Make Love To You Anytime" and included the Cale composition "Angel" on his most recent album, "Old Sock." Other songs like "Layla" didn't involve Cale, but clearly owe him a debt. The two also collaborated together on "The Road to Escondido," which won the Grammy Award for best contemporary blues album in 2008.