A conference phone call with Robert Plant, T Bone Burnett and Alison Krauss left reporters with a most obvious observation: The three are having a blast.

“Sometimes I want to pinch myself and say, ‘Am I really in the middle of this?’ ” Plant said. “There is such a great cacophony of sounds and style. I couldn’t wish for anything better than this.”

The group that Plant calls the Raising Sand Revue is on its second United States tour since the 2007 release of the album “Raising Sand.” It plays at 7:30 p.m.

Saturday, June 28 at the Harveys Outdoor Arena. The band also includes bassist Dennis Crouch, guitarist Buddy Miller and drummer Jay Bellerose.

While much of the concerts’ material comes from that CD, there have been three or four Led Zeppelin songs played each night.

“I’m surprised at the varying of the performances from show to show because of the personalities within the band being so grand and wonderful and expressive,” Krauss said. “Each tune has a different character because nobody’s afraid to (improvise). Everything has its own identity from night to night.”

Arena concert rocker Plant and bluegrass singer and fiddle player Krauss seem like an unlikely combination. But Plant, 59, and Krauss, 36, who met in 2004 at a Lead Belly tribute, mesh beautifully. And they don’t meet in the middle. As producer Burnett put the album together, the Raising Sand Revue leans heavily toward bluegrass.

“It was all about rhythm and angst until now,” Plant said of his musical approach. “I’ve learned how minimizing sound can be so effective. I’m working almost telepathically with Alison.”

Burnett, who worked with Krauss on the “O Brother, Where Art Thou” soundtrack, has learned some things, too.

“I was surprised to hear Robert on ‘Don’t Knock’ doing gospel blue notes,” he said. “That free thing. He’s not imitating anybody. It’s just coming right out of him. And I’m surprised to hear Alison singing as hard as she is singing on some of the tunes. That’s thrilling.”

Indeed, music critic Jim Fusilli of the Wall Street Journal wrote that Krauss sings the Tom Waits song “Trampled Rose” with “disarming power.”

Plant told Lake Tahoe Action that while he is in new territory, he hasn’t abandoned his blues roots.

“It’s become quite an illumination,” he said. “The qualities and inherent elements of a lot of the music that has been exposed to me recently ” they’re very familiar.

There’s a lot of blue in whatever this music is. And bearing in mind, even though Alison comes from a bluegrass root, what has been created in the chemistry of the three of us has it’s own kind of genre, really.

“I hear in the hill music of Kentucky, and the artists I’ve been exposed to in the last two years, I hear just as much soul. I’m not talking about contemporary bluegrass, I’m talking about mountain music, hill music. I find there are so many familiarities to me that I don’t feel at all estranged from my old root.”

Sharon Little, who will open the show with a seven-song set, is impressed with the audiences on this tour.

“They’re so respectful,” she said. “They’re waiting for greatness. It’s not the kind of crowd that talks or wants to dance. It’s the kind of crowd that likes to listen and respect.”

Nevertheless, those who call out for some Zeppelin won’t be disappointed. The band has played “Black Dog” (with banjo and acoustic bass), “When the Levee Breaks,” “The Battle of Evermore” and “Black Country Woman.”

Don’t be surprised if the trio comes out with a follow-up album.

“We’re all having a wonderful time,” Krauss said. “I think all three of us want to continue this, and are hoping it will go on and on. Union Station is like home. I am hoping to continue this and be able to go home too.”