Asa teacher, inspiration and friend, the late Sophocles Papas had a powerful influence on the emergence of guitar in America and the emergence of Washington guitarists in particular. So it's not surprising that five local guitarists who studied with Papas have come together, dubbing themselves, appropriately, the Washington Guitar Quintet. They have dedicated to him their debut program of classical, Latin, jazz and a Catalan folk song that was a Papas favorite.

The only group of its kind in the world (though there are some well-known ensembles focused on other instruments such as saxophones, drums, bass, clarinet and piano), the quintet will make its first public appearance 5:30 p.m. Friday at Georgetown University's Gaston Hall as part of the First American Classical Guitar Congress. The quintet is one up on the Los Angeles Guitar Quartet, but will probably have a hard time matching the Congress Guitar Orchestra (probably 200 members strong); that consolidation will close the Congress on Saturday night.

The quintet consists of Charlie Byrd, the Grammy Award winner who is apparently taking the Great Guitars format two steps further; Jeffrey Meyerriecks, a teacher at George Mason and Georgetown universities and the first American prize winner in Brazil's prestigious international Palestrina competition; Larry Snitzler, the international concert guitarist and composer who also teaches at George Mason and who hosted the National Public Radio series on Andres Segovia; John Marlow, head of the guitar department at American University and founder of the Licha Trio; and Myrna Sislen, who teaches at George Washington University. Sislen has just released an album recorded live at the Kennedy Center last year; the program included the world premiere of Meyerriecks' "Rhapsody."

Using five classical guitars is, Byrd concedes, "a whole different approach. It's a real orchestra, with a wonderful sound, but it takes a lot of work. Not many people have explored the possibilities of guitars en masse." As for the quintet's future, says Byrd, "we certainly do have a lot of fun rehearsing, so we'll keep it together even if we have no commercial success right away." Best of Washington

Eleven of the best musical groups and dance companies Washington has to offer will compete at 3 p.m. Sunday at the Ellington School of the Arts for the chance to perform in Peking and Bangkok as part of the Royal Pacific Cultural Exchange program, a cooperative effort by United Air Lines and Sister Cities International. (United has just started flying to those cities; the Sister Cities program is celebrating its 30th anniversary.)

The musical groups competing for the week-long, all-expenses-paid opportunity to be good will and cultural ambassadors are the Buck Hill Quartet, the Howard University Jazz Ensemble, the K. Shalong Trio, the Lisa Rich Quartet, the Mike Crotty/Deater O'Neill Quintet and Sweet Honey in the Rock. The dance companies include Dance Union, the D.C. Contemporary Dance Theatre, the D.C. Youth Ensemble, Perlo/Bloom and Company and the Upright Vertebrates. Local Notes

The Seldom Scene has made the second major personnel change in its 15-year history, with Lou Reid (no, not that Lou Reed, but the multi-instrumentalist who has been part of the Ricky Skaggs Band for the last four years) replacing lead singer Phil Rosenthal, who had replaced John Starling back in 1977. Meanwhile Starling, who left to pursue a medical practice in Alabama, has recently moved back to the Washington area; he's expected to sit in on occasion.

Rosenthal, informed of the change after a recent Thursday night Birchmere gig, said he was "shocked and disappointed" at the suddenness of the change, coming right before the lucrative summer festival season. "I'm just hurt that they did it so suddenly, as if I were an employe, not a partner." Rosenthal, who'll soon move back to his native Connecticut, added that he'd been thinking of leaving the band eventually to pursue his own interests, including the expansion of his own record company. He's already at work on a second album of bluegrass songs for children with Jonathan Edwards. Low-Paying Gig

When Gene Ryder and the Lifters opened for ZZ Top at the Capital Centre recently, it was their biggest crowd ever, but the paycheck didn't keep pace; they got $250 from the show's promoters, Cellar Door Productions, less than they get for a night's work in any local club. The band also had to hire five additional tech crew members and was not given a sound check. That's why they call it dues-paying . . . Several Washington groups did well at the recent National Association of Independent Record Distributors convention: Edwards and the Seldom Scene won the bluegrass album of the year award for their "Blue Ridge" collaboration (with the Johnson Mountain Boys receiving an honorable mention for "We'll Sing On"); Sweet Honey in the Rock won two awards, for best gospel album ("Feel Something Drawing Me On") and best women's album ("The Other Side"). Reggae specialists RAS got an honorable mention for Gregory Isaacs' "Private Beach Party" . . .

Chuck Brown's "Live at the Crystal Skate" is one of the hottest records in the Washington market; fellow go-go leader Trouble Funk recently completed work on a couple of numbers on Kurtis Blow's next album (also helping out, but on different songs: Bob Dylan) . . . Rosslyn Mountain Boy Joe Triplett's exquisite ballad, "Lesson to Learn," will appear on Rod Stewart's upcoming album; unfortunately, Stewart has already told Rolling Stone that it's his most "uncommercial" record in years, but he's probably just currying favors . . . Club Roxanne, formerly Adam's, will start showcasing local bands this week. Owner Shapur Moaveni's not a newcomer to live music, though; 15 years ago, he ran the Keg in Glover Park. That club was receptive early on to the evolving punk and new wave scenes in Washington, but Moaveni has indicated that for now he's not going to be booking punk, thrash or heavy metal bands.