Tower of Power blew out of the Oakland, Calif., in the early 1970s, propelled by the soul power that remains its foundation and inspiration.

Saxophonist and singer Emilio Castillo co-founded the band in 1968 with fellow sax man Stephen “Doc” Kupka. The young musicians played their versions of obscure soul tunes at Bay Area bars — until they got busted for being underage. The California Department of Beverage Control subsequently promised to revoke the liquor license of any bar in the Bay Area that allowed Tower of Power in the door.

The only thing left for the band to do was to practice, practice and, when it wasn’t practicing, starve.

Castillo reached the end of his rope. He prepared to move back to his parents’ house in Detroit. But the group had one last shot at staying in the San Francisco Bay Area: an audition at music impresario Bill Graham’s Fillmore West.

Tuesday nights were audition nights at the Fillmore. Tower of Power performed after four typical-for-the-era electric guitar bands.

“They were all the same,” Castillo recalled. “They were playing in A and E, the three-, four-chord rock music. And then we walked out. Big band. All these horns. Wearing navy bellbottoms and velour shirts that had no more velour on them.”

The people in the Fillmore who’d listened to the rock bands began leaving en masse.

“So we started with a James Brown song, ‘I Don’t Want Nobody To Give Me Nothing (Open Up The Door I’ll Get It Myself).’ We hit that first lick and, man, it was like an about-face. They all turned around. We played like our lives depended on it. In our minds, it did.”

The Fillmore’s response to Tower of Power’s audition wasn’t immediate. The depressed Castillo was already in Detroit when Kupka called three days later from Oakland.

“You gotta come back,” Kupka said. “He dug it.”

“Who dug it?” Castillo asked.

“Bill Graham dug it,” Kupka said. “They want to sign us to a record deal.”

Graham’s San Francisco Records released Tower of Power’s album debut, East Bay Grease, in 1970. The title was reference to the band’s hometown, Oakland.

“We say Oakland is the soul of the bay,” Castillo said. “San Francisco is a soulful place, too, but we’re from what we called the dark side of the bay. More blue collar, down to earth, real. That’s where Sly Stone was, that’s where the real good soul was.”

Just as Tower of Power is proud to call Oakland home, the group clings to its soul band identity.

“A lot of times people bring us on and say, ‘The greatest funk band in the world!’ But we’re a soul band. Funk is a part of soul. In soul you got funk, wrenching ballads, medium-tempo love songs, finger-popping shuffles. Soul is all encompassing.”

Castillo sings and plays sax in Tower of Power, but his most important role is band leader.

“My instrument is the band. I build a foundation and add stuff to it by using all of the talent at my disposal.”