There was some quite beautiful playing at last night's National Symphony Orchestra concert. Almost all of it, though, was in the second half, and most of that came from the glowing performance of guitarist Narciso Yepes.

He performed that splendid example of dry, transparent Spanish Romanticism, Joaquin Rodrigo's "Fantasia para un gentilhombre." It is, in fact, a suite based on lovely material by the 17th-century Spaniard Gaspar Sanz and the "gentilhombre" is Andres Segovia, for whom it was written.

Yepes' tone on the large 10-string instrument he favors was customarily glowing and his facility was up to his usual standards. The "Fantasia" admittedly is intended less as a major musical expression than as a solo vehicle, in the style of those others concocted for contemporary virtuosos of previously neglected solo instruments. But compare this gracious, evocative work, for instance, with the transcription of the already anemic Khachaturian violin concerto that flutist Jean-Pierre Rampal brought here in January and you will hear the difference. Several orchestra soloists, under conductor Rafael Fru hbeck de Burgos, contributed some fine playing as well.

Then they let go with a steady reading of Ravel's "Bolero" that developed into a mighty roar and left the audience cheering. Fru hbeck's steadiness was also very brisk. There was no languorousness, but also there was little subtlety of tone or phrase.

In the first half Fru hbeck's Beethoven was smooth, steady and not very penetrating. The "Ruins of Athens" Overture is mediocre Beethoven--there isn't much of that--and needs much spirit to be interesting. Last night there was almost none.

Then came the Beethoven Second Symphony, performed here for at least the fourth time since last August. And it's coming again in about five weeks with the St. Paul Chamber Orchestra. None of the performances have had any great distinction, including last night's. Fru hbeck did manage to get some compulsive bite into the last movement. But otherwise the high spirits that should seem to overflow in this work were missed. The moments where the combinations of rhythmic surprises and textural contrasts should make the first movement seem to burst open merely marched forward. And the wind and string tones of the slow movement did not sing as fully as they should have.