Fred Begun, the NSO principal timpanist for 48 years, at The Irish-Inn where he plays a few tunes with Brooks Tegler's jazz trio. (Dayna Smith/FOR THE WASHINGTON POST)

Fred Begun does not wear white tie and tails to perform anymore. He does not take the stage at the Kennedy Center. He sticks to jeans and sweaters when playing the timpani in his den and the drum set at a pub in Maryland.

A lot has changed since 1999, when Begun retired after 48 years as the principal timpanist at the National Symphony Orchestra. He lives alone — his second wife passed away 12 years ago — in a brick house in Bethesda on a street so quiet it seems as though the neighborhood has a mute button.

Begun has performed under the batons of Stravinsky, Stokowski, Bernstein and more. (This, for the uninitiated, is like learning to cook in Julia Child’s kitchen.) He authored “21 Etudes for Timpani,” which is used in conservatories around the world, and has given four world-premiere concerto performances for timpani. A good run, to be sure. He could have swapped song for silence a long time ago.

The hair he has left is wiry, white and gray. His skin is spotted with age. It’s a little late in life for a second act, but Begun, 83, is launching into new ventures with the gusto of a much younger man — or, perhaps, of a man exactly his age who doesn’t want to waste any time.

“I want to continue being on stage, with whatever music I’d be playing, and teaching and writing, rather than shutting it up,” said Begun. As far as he’s concerned, he’s not in retirement. He’s in a renaissance. “I never, never have had the ‘r’ word in my view. I’m still on the boards.”

Begun is as musically energized as ever. George Mason University, where Begun teaches a handful of master classes, is dedicating a percussion studio in the de Laski Performing Arts Building to him.

John Kilkenny, a percussion professor at GMU, said,“We wanted to honor Fred and his legacy of teaching and performing. He’s very passionate about working with kids [and] very enthusiastic about the next generation of musicians.”

On Sunday evenings, he plays with Brooks Tegler’s jazz trio at at the Irish Inn at Glen Echo, a session that at almost 30 years old is one of the longest-running steady gigs in Washington.

“This is a guy who is well known and well respected for a different kind of music,” said Tegler. “He could walk up there, sit down and be immediately accepted by everyone in that room.”

Begun is donating his library — timpani parts and scores, some autographed by famous conductors and composers, all with Begun’s original markings — and is contributing funds to the GMU project. The university hopes to have the Fred Begun Rehearsal Suite completed by the end of the calendar year and to endow a scholarship program for percussion students. The organizers are about halfway to meeting their fundraising goal, a number in the mid-five figures. A visiting-artist series, bringing guest performers and educators to the school, will be another component of the program.

“It’s a homecoming,” said Begun. “I like to think of it as going back to the roots of where it all started for me.

“I’ve never left the stage. I feel like I’m still on stage. As long as I’ve got that feeling of being on stage, I’m not going to sit on a couch.”

Begun talks the way every musician ought to talk, with the syncopated speech of someone who hears music when there isn’t any, in sentences littered with slang from a bygone era: “Man, that was hip,” and “I dug it, I mean, wow!”

It’s probably got something to do with his lifelong love of jazz. As a kid, Begun wanted a drum set, but his dad, a Russian immigrant, refused to buy one unless his son proved truly dedicated. So Begun made drums out of tin coffee cans, putting weights in the bottoms to achieve different sounds, until he got a snare drum at age 13 and a full set two years later. Begun played incessantly, practicing for six, seven, even eight hours a day.

He auditioned for the Juilliard School in New York on the snare drum and spent his entire first year of college hopping down to 52nd Street in Manhattan, trying to land a spot in a jam session at a jazz club, hoping to be as good as his childhood idol, a man he calls “my first hero: Gene Krupa.” He says the name like a spell.

“He was central casting,” said Begun. “He was glam. [In] musician magazines like Downbeat and Metronome . . . invariably there’d be a picture of Gene at a nightclub table, with his arm around Dinah Shore … and he’s in a bespoke suit, a monogrammed shirt, a Countess Mara tie, sipping a scotch and soda, and I’d say — Whoa, wait! That looks very cool. I want it.

“I wanted to be famous,” Begun said. “I had the bug.”

But his attempts at breaking into the New York jazz scene failed. “The Hail Mary came when I found that my act didn’t go over on 52nd Street, and I said, Okay, let’s really stop messing around and let’s get to work on the timpani. I made a vow to myself.

“There was a crucial moment when it became fun: when I played my first concert with the orchestra at school. . . . It was an electrifying experience. It was, wow, this is a whole new thing, a whole new world.”

Begun ultimately got what he wanted, becoming one of the NSO’s most recognizable and flamboyant members. “He’s dramatic,” said Kenneth Pasmanick, the former principal bassoonist for the NSO and a friend since they studied together at Juilliard. “He has a wonderful choreography … he [played the timpani] like a ballet dancer. He was just very deft.”

His flashy style belied a seriousness of purpose. “The orchestra really relies upon the rhythmic integrity and consistency of the command that the timpanist brings,” said Anthony Ames, principal percussionist for the NSO since 1968. “Fred never, ever missed.”

“If Fred was about to come in [during a piece],” said Ames, “I could see people leaning forward, assiduously focused. People bought box tickets just to lean in.”

On a Sunday in September at the Irish Inn at Glen Echo, Tegler’s trio is nestled in a dimly lit nook at the end of the room beneath a chalkboard advertising happy hour and imploring readers to “ASK US ABOUT LIVE MUSIC.”

Begun is hanging in the back, sipping a Guinness, waiting his turn as the band plays with Tegler at the drums.

After the set wraps up, Tegler announces, “We have a very special treat. We’re lucky to have Mr. Fred Begun back. Fred was the timpanist with the National Symphony Orchestra for 48 years.”

The crowd lets out a “whooo!” of approval.

“So please, a warm welcome, Mr. Fred Begun!”

Begun settles at the drums, his eyes nearly closed, his lips pressed together. He starts to play, beginning with the first four bars of “Planets” by Gustav Holst, a movement called “Mars,” before sliding into the rhythm of Dave Brubeck’s “Take Five.” His second number is “There’s a Small Hotel,” a 1930s pop standard by Richard Rodgers and Lorenz Hart.

Every sound is deliberate, from the shhh-ch-ch-shhh of the cymbal to the tat-a-tat-a-tat-tat of the snare drum.

For the last song of the set, Begun leads the band in “Sing Sing Sing,” the Benny Goodman band’s hit that Gene Krupa’s solo made famous. There it is, the tension, that come-hither to the dance floor: bom, bom-ba-bom, bom-ba-bom-ba-ba-bom! Begun’s body tenses and then, as the melody picks up, he goes loose around the shoulders, light at the elbows, fluid at the wrists.

Begun acknowledges “there are certain things that happen as a result of becoming 83,” listing various ailments afflicting his skin, his eyes, his blood.

None of those infirmities is evident now, though — maybe it’s just that flattering lighting— here, there’s something almost youthful about him.

He finishes the song and stands, bowing his head in thanks.

Tegler jumps up, clearing the distance from his chair to the drums in a few long strides. “Fred Begun, ladies and gentlemen, Fred Begun!”

He relieves Begun of his post and sits at the drums as Begun ambles back to his seat.

“Okay, here we go.” Tegler looks to the rest of the band. “G-flat? And a-one, two, three, four!”