It's not exactly of the magnitude of a Beatles reunion, but Alvin, Simon and Theodore—collectively known as the Chipmunks—have come out of retirement after 15 years. The boys kept the chirpy voices that sold an implausible 30 million records in the late '50s and '60s with originals like Alvin's Harmonica plus "cover" versions of the works of the Fab Four themselves. This time, though, the Chipmunks have an '80s look: Alvin sports safety pins and a Johnny Rotten coiffure; Theodore wears skinny ties; and bespectacled Simon has traded his old shoes for spiked greaser boots. Yep, their comeback LP is titled Chipmunk Punk, and they're gnawing on such contemporary chestnuts as Blondie's Call Me, Tom Petty's Refugee and the Knack's My Sharona.

The latest generation of Chipmunks fans includes even the artists whose hits they spoof. Guitarist Berton Averre of the Knack says: "It's a thrill, because I was a big fan of theirs as a kid." Chris Stein, Blondie guitarist and Debbie Harry's beau, cracks that it was "an honor equal to having the Bee Gees or Osmonds cover a song." Only Ric Ocasek of the Cars, whose Let's Go made the LP, reacted churlishly, snapping: "I think it sucked. It sounds like they did the album in a day."

Actually, the revival dates back to 1979 when Tom Owens, program director of KZEW in Dallas, used a Chipmunk-type sound on promo spots for the station. Deejay Jay Gilbert claims to have coined the term "Chipmunk punk" while prankishly putting his own squeaky overdubs on rock tunes while at WYSP in Philadelphia. After strong listener response, Steve Vining, 25-year-old director of artists and repertoire for Pickwick Records in Minneapolis, picked up on the idea from one of his Philadelphia field reps and suggested an LP. "My boss looked at me sideways," Vining recalls, "but eventually said, 'Do it.' "

Pickwick discovered that Chipmunk rights belonged to Ross Bagdasarian Jr., 31, son of the late songwriter-businessman who grossed up to $7 million a year on the gimmick beginning in 1958. Young Bagdasarian (whose sister Carol co-stars in the martial arts movie The Octagon)Joined the project as a consultant. Unlike his father, who originally did the voices of all three rodents and of the human in the group, David Seville, Ross Jr. left production to Vining and Pickwick studio manager Bob McNabb, 28. They used Bagdasarian Sr.'s method of playing instrumental tracks at half speed while vocals were recorded in a deliberately sluggish style. Then when played back at normal speed, the voices came out in the familiar Chipmunk warble. "We'd go bonkers during the sessions," recalls McNabb of the modest 50 hours of studio time needed to cut Punk. "Just imagine singing 'My-y-y-y, My-y-y-y, Sha-r-r-r-o-o-o-n-n-n-a...' "

Bagdasarian, a 1975 grad of Southwestern University law school in L.A., did insist on "total approval. I'd listen to their tapes and tell them which ones worked for me and which didn't," he explains. Also, the Sex Pistols and Kiss were no-nos, and some of the raunchier lyrics of other artists were changed to conform to the Chipmunks' wholesome image. "They're clean," notes Bagdasarian, "but not dull."

Henceforth Bagdasarian plans to restore family tradition by producing all Chipmunk LPs and personally doing the voice of Alvin. Ross and his new bride, Janice, are collaborating on their own album-cum-storybook, A Chipmunk Christmas—Alvin and the Spirit of Christmas. The L.A. couple also aims to spin it off for a 1981 holiday TV special. (Last year Ross sold reruns of his dad's 1961 cartoon series, The Alvin Show, to NBC.) But Vining and McNabb won't be left out totally in the Minnesota cold. "There are some royalties floating around," says Vining. And he and McNabb, still on salary at Pickwick, are mulling over a production partnership to cut hits for more conventional artists.

Bagdasarian himself talks about "branching out and producing other bands" but adds, "There is nothing as immediately enjoyable as the Chipmunks." For now anyway, Ross Jr. can't afford to practice law.