It was Richard Strauss all the way last night as Klaus Tennstedt led the Philadelphia Orchestra at the Kennedy Center in the suite from "Der Burger als Edelmann," and the tone poem Also Sprach Zarathustra

In both works there are passages for the violas, cellos, and, after a while, the first stands of violins. Every time this combination came around, the resulting sound was one of those textures you hear only from these Philadelphia musicians.

The suite for the Moliere play, better known by its French title, "Lebourgeois gentilhomme," is one of the special delights in the Strauss repertoire. Scored for around 40 players, it often assigns to each an individual line. Ther are gorgeous passages for piano, violin, oboe, flute and cello, all of them done with elegance land polish. The unnamed pianist was a particular joy.

The transparent writing exposes each player to unusual perils of intonation and attack, but with few exceptions, these were handily overcome. The suite demands the utmost influent, intimate chamber-music style from the conductor. Tennstedt was a model in his treatment of the elusive work.

The big tone poem came off wonderfully. Again it was Tennistedt's control, notably in holding back the large moments, as in "Joys and Passions," and, with marvelous effect, in opening the fugue, that created the grand tension necessary for the ultimate effect. It would be ideal if the coming of the dawn had been similarly held back. Norman Carol's violin, flawlessly partnered by William de Pasquale's, sang with special impact all evening.

There was a minor organ slip, and organist Smith, walking in and out during the work, had an unsetting effect. But the cumulative power of the score was magnificent, as Tennstedt brought it to a hushed close that summed up all the philosophical questions raised in the music.