Conductor Raphael Fruhbeck de Burgos is not a flashy virtuoso. There is little of Von Karajan or Bernstein in his self-effacing manner. He is something rarer among his conducting peers: a virtuosoo who calls himself "a veery normal personality."

He has declined, for example, to accept a major American musical directorship - several have been offered - because his wife wants to stay in Spain, his native country but hardly a hotbed of musical action.

That is the only explanation that Norman Carol, the concertmaster of the plush Philadelphia Orchestra. Can produce for Fruhbeck's restriction in this country to the conductorial sidelines, lucrative as they are.

Says Carol, who has played with Fruhbeck many times, "It baffles me why his ability has not been wider known. He is a logical man for one of the major American orchestras to pick up, and yet that has not happened.

"Let me explain it this way," says Carol, who will be performing under Fruhbeck at Saratoga later in the month. "He is extremely precise and disciplined. He knows exactly what he wants, and like the very best conductors he lets you know what he wants, but that's often very complicated. That doesn't bother us, because he's got the stick and the brains to communicate it. He would never have to run from some sort of challenge."

He's a specialist in Spanish and French music, but he covers the basic repertory. His notion of the ideal symphonic concert is a two-part one: Beethoven's "Eroica" symphony and Stravinsky's "Le Sacre du Printemps." It's like putting into the same gallery Michelangelo's "The Last Judgement" and da Vinci's "David" - and he's done it. What chutzpah!

During his rehearsals here for last night's Wolf Trap concert with the National Symphony, and for one coming up next week; Fruhbeck seemed the model of the genial, gentlemanly Spaniard.

Yet he is regarded with awe by the musicians of the National Symphony so that when he walked on stage at 10 a.m. yesterday morning there was an ovation, a gesture not lavished even upon the Rostroproviches and the Doratis of the world.

"It's mostly in the stick technique," says Fred Begun, the orchestra's veteran tympanist, of Fruhbeck's reputation.

As Fruhbeck himself explains, "It really ought to be 90 percent in the stick. And the adjustments are in the left hand."

In yesterday morning's rehearsal, however, much of Fruhbeck's directions came from sung phrasings. He would never make it as an opera singer. But he knows how to make his point.

Fruhbeck had only three hours to rehearse his concert for last night. But there is general feeling among orchestra players that few other conductors can accomplish so much with so little time.

Dotian Carter, the chief harp players, says, "He has a way of looking at you, and saying 'I know you may miss this.' And then it becomes twice as likely that you won't."

Fruhbeck dismisses atuocracy as a technique. "It's conviction that comes. I think that if a conductor asks an orchestra something that counts, he has to convince them that it counts. It's conviction that counts, not autocracy."

To Fruhbeck, the rudiments of conducting are simple and extraordinarily demanding: 1) you must know "exactly" what you want; 2) you must have the skills to communicate this to the players; and 3) you must have a rapport with them ("the most extraordinary conductor in the world may ruin his performance by failing to get his message across?").

Fruhbeck approaches with the idea of solving the greatest difficulties first. During his season of five programs with the NSO last summer he launched the rehearsals with the enigmatic final dance from "The Rite of Spring," one of the real technical belly-whoppers of the repertory. The key instrument is the tympani, and as tympanist Begun recalls, it, the passage was repeated five times straight. Begun had never been through anything like before, and it was from there that his enormous respect for Fruhbeck began.

"I believe in starting out by concentrating on certain trouble spots, like the finale of 'Sacre,' then doing the pieces straight through. In some cases it works out normally, because in a piece like Schubert's 'Unfinished Symony, it is the slow opening that is the hardest point."

Why isn't Fruhbeck already running one of America's orchestras, if he's better than most of the people now beating time in this country?

Despite his attachment to Spain, the truth is that he has yet to get the offer that he couldn't refuse. There have been offers from smaller American orchestra - and from ones in Germany and Japan. He just doesn't need them. On the other hand, if the National Symphony were to call some day - or the Philadelphia - Fruhbeck might find himself suddenly the host in the concert hall, rather than the perennial gut.