Bill Kreutzmann is calling from Mickey Hart's studio north of San Francisco, where the two Grateful Dead drummers' band, the Rhythm Devils, has been rehearsing. He says they're having so much fun that one day they played for 13 hours, a mix of newer tunes and Dead classics.

Bill Kreutzmann is calling from Mickey Hart's studio north of San Francisco, where the two Grateful Dead drummers' band, the Rhythm Devils, has been rehearsing. He says they're having so much fun that one day they played for 13 hours, a mix of newer tunes and Dead classics.

"These guys are doing them as good as we ever did them," Kreutzmann says. "I'm having the most fun right now playing music I've ever had."

He's pleased enough with a new cut of Robert Hunter and Jerry Garcia's country-bluesy "So Many Roads" that he's just posted it on Facebook and at billkreutzmann.com.

The band will play Sunday at Britt in Jacksonville, the third stop on a tour that will eventually take them to the East Coast. It will be Kreutzmann's first visit to Britt, although Hart has played here in different projects, and the drummers' former rhythm guitar colleague in the Grateful Dead, Bob Weir, has played Britt twice with his band, Ratdog.

The Rhythm Devils are Hart and Kreutzmann on drums and percussion, Keller Williams on guitar and vocals, Sikiru Adepoju on talking drum, Davy Knowles on guitar and vocals and Andy Hess on bass.

"Keller knows the material well," Kreutzmann says. "Andy is a wonderful bass player. Davy is a leader. Sikiru is a master drummer. He's very quiet — his drum says it all."

Kreutzmann grew up in the Bay Area, got together with Garcia in the mid-'60s in what would become the Grateful Dead and played drums in the band until Garcia's death in 1995, most of the time with Hart alongside. The two drummers gave the Dead a massive rhythmic base. They would play long, improvisational percussion duets and solos in the middle of the second set of Dead shows.

The segment was sometimes called "rhythm devils" but came to be known simply as "drums," which preceded "space," in which Garcia, Weir and bassist Phil Lesh would let the musical bottom drop out for free-form jamming.

Kreutzmann moved to Hawaii in 1996, bought some land and devoted himself to growing exotic flowers, with long breaks for occasional tours with the surviving members of the Dead in various groupings.

He says the Rhythm Devils already have enough material down for four sets without repeating a song. They've been working on transitions — a longtime hallmark of Dead shows — generally keeping them short. They'll use set lists, something the Dead eschewed.

He says Dead lyricist Robert Hunter, Garcia's longtime writing partner, has found his muse again.

"He's in a writing frenzy right now. He sends about a song a week. We can't keep up with it. He always has a really good story."

Ninety percent of the Dead songs the band does are Hunter-Garcia songs, Kreutzmann says. Another chunk of the Dead songbook consists of songs by Weir and John Barlow.

Kreutzmann says he doesn't compare bands or songs.

"It's like apples and oranges," he says. "I just go, 'That's that,' it's just different. You wouldn't compare Garcia to Miles Davis. I like it all."

Right now he's liking playing with Hart, who plays a computer workstation/drum kit called RAMU, or random access musical universe. You have to hear it to get it.

"His electronics makes it way fun," says Kreutzmann. "On our best nights we sound like a fusion band."

He says he was home with his girlfriend, Amy, when something he didn't know came on the stereo.

"That sounds good," he said. "Who is it?" "It's you, you nut," she said.

"That happens to me when it's really good, in the immediacy of the moment," he says. "That's a good thing."

When the tour is behind him Kreutzmann expects to return to Kauai and put in some new tropical flowers to go with his mango and citrus trees, maybe hang out with humpback whales — without getting too close — on his 22-foot catamaran.

"I'm really lucky," he says. "I'm flexible. I wake up happy and can touch my toes. I guess I'm aging gracefully."