THEY PLAYED superbly," pianist Lilli Kraus said. "I found them excellent and paricularly sensitive."

She was not referring to her recent appearance with the National Symphony.

She was talking about last spring and that other orchestra, out in northern Virginia, the Fairfax Symphony.

"We're kind of a sleeper out here," says concertmaster Margaret Thomas, who also plays with the Kennedy CenterOpera House orchestra. "People downtown think I'm nuts for playing with the Fairfax Symphony. They have no concept of the caliber of playing."

This weekend the Fairfax Symphony opened its 23rd season, which will include an appearance by cellist Janos Starker and, as usual for the past 6 years, a concert in the Kennedy Center. With 116 players -- 12 more than the National Symphony -- it aims to be the best of its kind, or, as its publicity proclaims, "a first-class orchestra in a first-class community." By most measures it is succeeding beyond all expectations.

The American Symphony Orchestra League says that the Fairfax is probably unique among the nation's 800 community orchestras, behaving like a large metropolitan symphony on a budget one-fifth the size. Most community orchestras do not have major soloists, give 16 full concerts a season, run a chamber music institute and master classes, perform on weekdays or in the summer. The Fairfax does all of the above and more.

Moreover, it is virtually unheard of for such an orchestra to go on an international tour. But next June the Fairfax Symphony plans to go to South America at the invitation of the Colombian government.

The success of the Fairfax is an unlikely story that amazes even its most ardent fans.

It is a history of desperate measures. Symphony members began by carrying in High's punch and homemade cookies to woo listeners. They brought in puppet shows, and at one point even hired Ranger Hal, a local TV personality, to boost the audience -- and some children threw up with overexcitement. In the melee, music was lost, and so was one soloist -- locked in the men's room. Often, members were so busy catering, promoting and cleaning up that they never got to attend the concerts. c

Ten years ago, if anyone had been asked to name the community orchestra in the area least likely to succeed, the Fairfax would have won, hands down. And voting in agreement would have been almost everyone connected with the orchestra.

Orchestra and audience counts were not far apart, and at that time the Fairfax had fewer than 60 players. A board member from the period recalls hearing her first concert and thinking, "My god, they can't even play together." Women in the Symphony Association, a support group, were inclined to go to the coffees but not the concerts. The nadir was an American Smphony Orchestra League study made in 1968, which tactfully suggested that the Fairfax merge with another community -- or, in other words, disappear from sight.

The obvious question is: Why didn't everybody chuck it in? Stubborness," says manager Barbara Serage. "We didn't have good sense," says former board president Ellen Anderson, who was invited to join the board after writing a review that condemned the orchestra.

"We knew we were in a slump," recalled Penny Farris, a school teacher, one of the few charter members still playing with the orchestra. "But we knew we had the potential and we knew the audience was there."

Farris revealed that the orchestra asked for the study, voluntarily submitting itself to outside criticism. The report may have stung but also touched a deep sense of pride. "We were damned if we were going to settle for that other orchestra's level of playing," said one board member, explaining why the idea of a merger was out of the question. With blind faith and dogged determination, the board opted for a new conductor and higher goals.

In 1971 William Hudson, a young conductor not long out of Yale graduate school and Tanlgewood studies with Max Rudolf and Eric Leinsdorf, took over direction of the Fairfax Symphony. He told Serage: "I like a challenge."

"Good," she replied, adding: "And I hope you have a sense of humor because you're going to need it."

Hudson, a professor music at the University of Maryland, admitted that there was more pain than pleasure in the beginning.

"In the early stages I dreaded coming over to go through rehearsals," he said. "We had the worst reputation in the area."

Again, the obvious question: Why didn't he quit?

"I've always had this feeling that I could take an orchestra at whatever level it was and build it, if the board of directors would give me a free hand," explained Hudson. Slowly, patiently he tackled each problem. "One of the first things I got was 'We're here to have a good time.' I said that the way to enjoy yourselves is to play well.Then you will have a common sense of pride and the social part won't have the pull it does now because of a defeated orchestra."

When some board members suggested that community orchestra should remain open to everybody, Hudson replied: "If the orchestra is for everybody, it's for nobody. It's like a basketball team. If just anybody can play, there's no satisfaction -- and you ain't winning games, either."

Hudson made it clear that orchestra members, who were accustomed to leaving music on the stands after a rehearsal, were expected to practice. "Rehearsals are not for learning the music," he told them. "They are for developing a unified style."

The second year Hudson instituted auditions for every player, despite what he described as "pandemonium and general terror." Players, whether brand new or 10-year veterans, are still auditioned and ranked each year, a procedure now accepted as normal.

"At first I didn't like the idea," said violinist Emile Zimmermann, a charter member and former concertmaster of the orchestra. "But after a while I saw that even if do play for many years with the orchestra, when better players come along they should be able to bump you."

This season Hudson has asked Zimmermann to perform a solo with the orchestra. "That's something I've dreamed about ever since I was a little kid and never thought I'd do," said Zimmermann, an insurance salesman whose wife, six children and 81-year-old mother will come to hear him.

For the players -- who range in age from 16 to over 60, and include housewives, lawyers, professors and diplomats -- the demands are heavy. Apart from individual practice, they rehearse for three hours on Monday nights, another three hours on Wednesday nights. The week of concerts requires an additional Friday-night dress rehearsal and a Saturday night performance.

As the demands have increased, the players have responded by working harder, "looking ahead to something we're going to be," as Hudson said. "People have had their lives open up musically. They're in uncharted waters and that represents adventure for them."

Housewife Margaret Thomas joined the Fairfax eight years ago to get back into playing, which family demands had shoved aside. She became its concertmaster, preformed concertos with the orchestra, and took advantage of its masterclasses, which are free for orchestra members. Now she plays professionally at the Kennedy Center, but "without that push I wouldn't be playing downtown."

"I feel I'll always play with the Fairfax," she added. "Downtown we learn a lot fast. Back in Fairfax, we have the chance to think about the music. One feeds the pocketbook, the other the soul."

In less than 10 years, the orchestra's budget has moved from $13,000 to $154,000, the number of full concerts from 6 to 16, the people served from 2,500 to 60,000 and a vast complex of activities, ranging from a chamber orchestra to an extensive "Hello, Symphony" program in the schools has been developed.

This season, state and county grants will total $45,000. Another $69,000 will come from earned income, which includes program advertising and a $15 subscription series 75 percent sold out this year. Private and corporate contributions are expected to reach $40,000 with significant increases from national firms with offices in Northern Virginia. IBM, Xeros, the BDM Corporation, Dyanlectron and Cerberonics have contributed because, as BDM president Earle Williams said, "The symphony serves as a catalyst, a point in the community where old-line established families and newer business people can meet and get to know one another."

Operating from her dining-room table, manager Serage (a former housewife and teacher) seized any opportunity for expansion that came along. When the orchestra received a memorial fund to bring in guest soloists, Serage got a state grant for master classes by these artists. Recalling the first soloist who gave a master class, violinist Sergiu Luca, Serage said: "My feeling was that if you had somebody like, that you didn't just run him across that stage and out the door. You planted him in the community and let folks get exposed to him." Giving a master class is now a regular feature of a Fairfax Symphony guest artist contract.

When necessary, Serage has been willing to go out on a limb. "I've spent a lot of time making my word good," she said. Last November, for example, in return for rent-free symphony offices in a house belonging to the county park authority she pledged a summer chamber-music institute at the facility. When the pledge was made, there was no money, no teachers and no students for such an institute. By summer everything was put together and the institute proved such a success that it will probably become a regular event.

Another challenge facing the orchestra is overcoming the stereotype of community sympohonies. "I know what people think if you ask them to come hear an all-volunteer orchestra play in a high school auditorium," said Hudson. "I cringe when somebody asks me to do it. And all these orchestras say they're good. How are people to know we're any better unless they come hear us?"

A possible answer now being discussed is an arts complex in a Fairfax County community center, but years might elapse before it becomes a reality, if ever it does.

a deeper challenge stems from the orchestra's own success. As its quality continues to rise, so do the standards of playing. A number of area professionals are, in fact, already volunteers with the symphony. Some people see it moving inevitably toward professional status. Others feel that such a step would destroy the orchestra's special character.

But "an orchestra can't stand still. It can either grow or die," said Serage. CAPTION: Picture, The Fairfax Symphony performing in the Kennedy Center. "A first-class orchestra." By Richard Braaten; Copyright (c) 1979