AN ORCHESTRA THE DUKE WOULD BE PROUD OF

Five days after his father died in May, 1974, Mercer Ellington flew to Bermuda with the orchestra he had inherited to fulfill an obligation Duke had sworn would be honored.

“I want to have a band Pop would be proud of,” his son said on that occasion, and since then he has tried bravely to live up to a promise that might have seemed impossible to keep.

Next Friday, just 13 years after the father-to-son transition, the Ellington orchestra will perform during the opening evening of the Queen Mary Jazz Festival. This will be a rare opportunity--the first since Duke’s death--for a Los Angeles audience to hear the band under concert conditions.

Keeping the Ellington name alive has been no problem; by now, it is engraved firmly in the history of 20th-Century music. Keeping the quality of the music unspoiled is another matter, one that has found Mercer Ellington dealing with the perennial question: How much should this timeless music be updated, if indeed it needs changing at all? How does one retain in the ranks of the musicians that unique sense of personal identity that became so much a part of the Duke’s own genius?

Mercer, pausing during a tour, called from New York to bring the picture up to date. “We’re actually playing more Ellington than we ever did before,” he said, “and the joy of it is that the things we’re playing are authentic. We even do a version of ‘Solitude’ with that quiet, trio-like sound, the way Pop did it originally. And Barry Lee Hall does the original version of ‘Do Nothing Till You Hear From Me.’ ” (Hall, to whom the late Cootie Williams bequeathed his trumpet when they were brass section team mates, has become a key figure in transcribing the original Ellington arrangements from records.)

Longevity was always a hallmark of Ellingtonia, in terms of the music and the men who played it. In Duke’s day, you could measure a sideman’s tenure in decades. Though they were absent for various periods, such giants as Johnny Hodges, Harry Carney and Cootie Williams, all of whom joined the band in the late 1920s, were on hand for at least part of the 1970s.

“Nowadays, we measure in years rather than decades,” Mercer said. “Our oldest inhabitant is Chuck Connors, who joined the trombone section in 1961. But we still have several others who were in the band with Pop: our singer, Anita Moore, and the drummer, Rocky White, and Barry Lee Hall.” Mercer joined the band in 1965 as trumpeter and road manager.

The continuity is further maintained by the occasional presence of various alumni. Trombonists Buster Cooper and Vince Prudents, both now based in Los Angeles, will be on hand next Friday. A couple of weeks ago, clarinetist Jimmy Hamilton, a cornerstone of the reed section from 1942 to 1968, left his Virgin Islands home to play a gig with Mercer in Copenhagen, now the Ellingtons’ second home. (Mercer’s wife is Danish; he spends about three months of every year there.)

“That was a marvelous job,” Mercer said. “They flew us over to play a battle of the bands, competing with this Danish Radio orchestra. It was a benefit for the Ben Webster Memorial Foundation.” Webster, the tenor sax behemoth of Ellington’s 1940s band, died in European expatriation.

“The band sounded great, but the Copenhagen writers were indignant; they panned the hell out of us.”

Was that just chauvinistic jealousy?

“Absolutely,” Mercer Ellington answered. “The truth is, we killed ‘em!” He laughed with an air of total conviction. “You’ll probably be able to find out for yourself, because they brought a half-dozen cameras in from Stockholm, and they’re bound to make some kind of TV special out of it.”

In addition to reviving the classic Ellington repertoire, Mercer has picked up at an important point where his father left off. Just before he died, Duke was working on a musical, “Queenie Pie,” for which Mercer took over the balance of the composing.

“We finally got the show on stage last year, in Philadelphia and Washington. The band didn’t take part in it, but I kept a close watch on the show. It was very successful, closed to standing room, and made good money, so we’re hoping to take it on the road and wind up on Broadway.”

Though Mercer Ellington’s own career as a composer has been erratic, he has had his share of successes. The best-known work that bears his name is “Things Ain’t What They Used To Be,” though his talent is better represented by the colorfully textured “Blue Serge” and “Moon Mist.”

“Lately,” he said, “I’ve been making sure to do a little writing now and then; busy as I am with running the band, I like to contribute to the music. Right now, I’m trying to complete what I hope will be the ultimate arrangement on ‘It Don’t Mean a Thing If It Ain’t Got That Swing.’ I started to do it for the new album, but it didn’t quite work. It swings, it sounds good, but it’s not authentic. I’m going to keep on doing it, as they say, until I get it right.”

Representation on records for the present orchestra has been inadequate. During the 10 years that followed Duke’s death, Mercer made only two albums. Lately, though, this aspect of the band’s work has taken on new life. “Hot and Bothered,” a first-rate series of re-creations, was issued in 1984 on Dr. Jazz Records; an album with Diahann Carroll, singing her tribute to Ethel Waters, has just been reissued on compact disc (Bainbridge), and “Digital Duke,” the band’s latest venture, with Clark Terry and Louis Bellson (both graduates of the 1950s band) and two guest soloists--Eddie Daniels on clarinet and Branford Marsalis on tenor sax--will be released momentarily on GRP.

“I still believe in what Pop told me,” Mercer said. “He was convinced that the whole basis of being in this business is staying on records. If we keep on doing what we’re doing--and I’m very happy with the way this new album has turned out--sooner or later something great is bound to happen.

“Yes, we’re making pretty good progress, and I’m keeping my fingers crossed. Meanwhile, I’ll tell you one thing--I’m getting more pleasure out of it than ever.”