"You still got it, Tex," yelled a woman from the audience as the applause was dying down after the "St. Louis Blues March," and Tex Beneke, 75 years old and still sounding good, broke into a smile that embraced the whole Merriweather Post Pavilion.

Give or take a few gray hairs and some unfamiliar faces behind the brass and reeds, it could have been 1946, when Beneke inherited the Glenn Miller orchestra, where he had been featured as a tenor sax soloist and vocalist. The arrangements this weekend were the ones familiar from old records and old memories, and the crowd seemed to know them as well as the musicians. Two introductory bass notes were enough for them to recognize (and applaud wildly) the classic "Little Brown Jug," and when Bob Eberly swung into the chorus of "Amapola," he had half the audience singing along with the well-remembered lyrics: "Amapola, the pretty little poppy/Must copy its endearing charms from you . . . "

After opening the show with an evocative fragment of "Moonlight Seranade," Beneke welcomed the many members of the audience "in my own age bracket" but added that 'I'm even more happy that there are so many teenagers around the country who are latching on to the bigband sound." There were, in fact, a good many in the audience (and in the band, too) who had not been born when the songs on the program were composed. One or two had mixed feelings ("I wonder if they're serving Geritol at the refreshment stand" was overheard in the crowd), but others were clearly enchanted with the sound of the '40s. "All those instruments are acoustic," said one convert from rock, a tinge of amazement in her voice.

A lot of the proselytizing on big bands' behalf has been done by a Baltimore AM station, WAYE, whose name was warmly applauded when it was mentioned from the stage, but intensive missionary work is still being done by Beneke, who is as busy as he wants to be a generation after the big bands supposedly breathed their last.

"I do these shows with Bob Eberly and Helen O'Connell all over the country," Beneke said after the show, but it's not exactly the barnstorming life of the '30s and '40s, when big bands traveled everywhere in their own buses. Now, Beneke travels with his arrangements and whips together a local band in each city he visits. "I have different groups in practically all the major cities; I just call my contractor when I'm coming in and say, 'I want my regulars.'"

At intermission and after the show, his dressing room is usually full of young musicians asking questions about his music, his reeds and his technique. Any time the American public decides it wants a massive big-band revival, the material will be ready, Beneke said. "Most young players today can outplay the average old time band members."