DIRT BAND, AT 21, STILL EVOLVING

About this time last year, the Nitty Gritty Dirt Band celebrated its 20th anniversary with an all-star concert lineup in Denver that included Emmylou Harris, Jerry Jeff Walker, John Prine, Rodney Crowell, Doc Watson, Ricky Skaggs and dozens of other musical friends.

The veteran country rock band, which has survived for two decades with only intermittent commercial success, is still evolving. Last winter, longtime member John McEuen quit to pursue a solo career.

Bernie Leadon, one of the original members of the Eagles, has replaced McEuen on a current tour with headliner Reba McEntire that brings the group to the Universal Amphitheatre Saturday and to Irvine Meadows Amphitheatre Sunday. Coincidentally, the concert in Orange County on Sunday comes exactly 21 years after the Dirt Band made its public debut at the Paradox club in Orange on May 10, 1966.

Because Leadon was part of the same circle of Southern California musicians that in the 1960s spawned the Dirt Band, his addition to the lineup has made for an easy transition in the wake of McEuen’s departure, Dirt Band founder Jeff Hanna said. Leadon, like McEuen, is a multitalented instrumentalist who will play guitar, banjo and mandolin and also contribute vocal harmonies.

“I’ve known Bernie for almost as long as there has been a Dirt Band,” Hanna, 39, said by telephone during a rehearsal Wednesday for NBC-TV’s “The Tonight Show.” The group made its first appearance on the show in more than a decade. The band is also due to appear May 21 at the opposite end of the network’s TV day on “The Today Show.”

“Naturally, it’s a little different,” Hanna said of the personnel changes. “Every musician has a different approach. I’d say John’s expertise is more the Appalachian music (and) acoustic stuff. Bernie leans more toward rock ‘n’ roll, although he has played a lot of bluegrass too. It’s always fun to have new blood and an influx of new ideas. When you’ve been doing this as long as we have, you need that.”

Drummer Jimmie Fadden, who was also in the group at its inception amid the Long Beach-Orange County folk scene of the mid-’60s, remains in the lineup along with singer and guitarist Jimmie Ibbotson (who joined in 1968) and keyboard player Bob Carpenter, a Dirt Band member since 1978.

Group publicist Mark Bleisener, who continues to work with McEuen, said the departure of the Garden Grove-raised instrumentalist was no surprise but rather the natural result “of being locked up in a bus with those guys for 20 years.”

Whether Leadon will remain with the band on a full-time basis has not been decided because, Bleisener said, “everybody wants to be very sure. They wanted to make sure things worked out (on tour) before he goes to full-fledged status. But the tour has been working out really well, and I wouldn’t be surprised if he becomes a full-fledged band member soon.”

It has been 10 years since the Dirt Band became the first American rock group to tour the Soviet Union. This summer the band will cross the Atlantic once again, but their forthcoming tour includes only free world stops in West Germany, the Netherlands and England.

Last year the band performed in Belfast, Northern Ireland, which Hanna described as a “pretty bizarre” experience.

“I’m not used to driving down the street and seeing anti-personnel carriers, guys with machine guns and all that security. It was a hot time of year--Easter week--and there were a lot of parades and rock-throwing. But it didn’t really affect us. That’s their trip, and they’ve been doing it for 1,000 years.”

With it’s latest single, “Baby’s Got a Hold on Me,” at No. 11 in Billboard this week, the Dirt Band is poised to chart its 10th Top 10 country single. While the group’s greatest following in recent years has been the country audience, several songs on the new “Hold On” album have a harder rock edge than the last few Dirt Band albums.

“I think this album sounds more like the Dirt Band does live,” Hanna said. “We’re a lot more high energy than some of our records sound.”

Still, the band’s basic, innocent charm--which stems from Hanna and Ibbotson’s guileless vocals--remain at the core of its sound, even when performing Bruce Springsteen’s Cajun-flavored rocker “Angelyne.”

Said Hanna with a laugh, “We’re not going to be confused with AC/DC.”

FREE AGENT: Agent Orange will play a free show at noon Saturday at Cal State Fullerton as part of the university’s Spring Fest activities. The band’s appearance is in conjunction with a 72-hour skateboarding marathon featuring top skateboarders Tony Hauk and Lester Akai and others. The show is sponsored by the Tau Kappa Epsilon fraternity.

Agent Orange’s participation is a reflection of the band’s strong following among skateboard enthusiasts. For the last few years, the Fullerton-based trio has even successfully marketed its own Agent Orange skateboard through a Huntington Beach sporting goods manufacturer and its music has been used in a popular skateboarding video.

Proceeds from the skateboard marathon will go to the Orange County chapter of Mothers Against Drunk Driving (MADD). The TKE fraternity will also present a screening of the 1982 Rolling Stones concert film “Let’s Spend the Night Together” Saturday night. The film will be shown on campus at 8 p.m. on a 60-by-80-foot screen using what is reported to be a 100,000-watt sound system.

LIVE ACTION: A second Deep Purple performance at Irvine Meadows Amphitheatre has been added for May 23. Tickets go on sale Sunday. . . . Blue Trapeze will be at Big John’s in Anaheim on May 16. . . . The Knack will play a benefit for the Cal State Fullerton gymnastics team on May 28 at the Coach House in San Juan Capistrano. . . . The Williams Brothers are scheduled to play Goodies in Fullerton on May 25.