"Fairfax Symphony is very much of a training ground," says its concertmaster, Margaret Thomas. "When you spend six weeks getting ready for a concert, you know you have to learn something."

The diminutive, dark-haired Fairfax woman "grew up" in the symphony, she says. The Fairfax Symphony was her first orchestra outside of school (the Oberlin Conservatory of Music), and it took her on after an 11-year separation from her instrument.

"I had small children and couldn't practice enough, so I gave it up," she explained. "With the violin, either you progress or you deteriorate. There is no middle ground."

Thomas said she returned to her instrument "when my youngest boy was a baby -- he had colic and I needed the violin as therapy against all that crying." She joined the symphony in 1971, the same year as conductor Bill Hudson, and she attributes her growth to his "willingness to give me that first chance."

Hudson listened in 1973 when she asked to be concertmaster, a position that calls for both an excellent musician and a sensitive leader. As concertmaster, she leads 16 to 18 other musicians in the violin section. "That in turn leads the rest of the strings," she said.

Thomas also holds this position in the prestigious Friday Morning Music Club in the District and plays first violin in the Kennedy Center Opera House Orchestra. But she stays with the Fairfax Symphony, she said, for the opportunity to lead and because "I think I owe it to them."

The orchestra, just beginning its 26th season, has among its members a half-dozen "professional musicians, who help maintain a certain quality," Thomas said. But she praised all the members as dedicated, including those who "come because they want to learn."

"We have times when rehearsals and performances can take up to four nights a week, and with members coming from as far away as Columbia, Md., that takes a special kind of commitment," she said.

The desire to learn is rewarded in Fairfax, Thomas said. "Bill is a teaching conductor. He is continuously teaching people how to play together, how to keep the balance in the orchestra."

The balance has to be maintained musically and humanly, she said. "Every orchestra is a room full of prima donnas. You're putting yourself on the line every time you play."

But Thomas said she decided early "that I would always enjoy playing the violin, despite the politics that goes on around it. And there are a lot of politics in music -- who gets to play what, who's sitting where, all those things."

But when it comes to preparing for solos, Thomas said, she leans on Hudson and encourages his criticism.

"I've often wondered if I should be concertmaster there," she said. "I'm a detail person and very good at keeping track of all of the details in a concert, but I'm not the flashiest violinist. I have told Bill that if the time comes when the symphony outgrows me -- that the quality increases past my expertise -- then he should let me know and I'll step down.

"I hope that's how it happens."