The Cleveland Orchestra is in town for two Kennedy Center concerts, the second of which, to be played tonight, is likely to be one you will be sorry to miss. It will open with the first Mozart symphony, close with the last one by Tchaikvosky, and in between offer the only violin concerto by Samuel Barber.

Lorin Maazel is conducting both Cleveland programs. If he is as good tonight as he was yesterday afternoon, it will be a memorable evening. On Sunday, Maazel, in the most heroic of moods possible at a symphoney concert, began with "A Hero's Life" by Richard Strauss and ended with the "Heroic" Symphony by Beethoven. That's a lot of heroism, all in the key of E Flat.

But programs depend not only on what is played but how it is played. The Cleveland Orchestra was in its super form Sunday,which mens it was as good as anybody in the business these days.

The Strauss tone poem calls for a crackerjack outfit with special strengths in the strings to match the power the composer wrote into its wood and brass choirs, not forgetting the big bass drum that dofinates the battle scene. On Sunday the Clevelanders had an ideal mixture of razor sharp precision when needed, and expressive lyricsm when that was appropriate.

They gave Maazel every surge in sound he called for and shaded the dynamics likea bunch of whizards of his cue. The poise of the wind on the final chord was perfect. The Strauss stands or falls, interpretively, on the conductor's willingness ot let it time to drop restraint and let the music expand. Its sweet, songful pages call for complete freedom in rubato, a kind of intimacy that makes bato, a kind of intimacy that makes you forget how loud the piece sometimes becomes. All the Maazel gave his listerner in a performance that could hardly be surpassed.

"Helenleben," to give its original title, is also practically a violin concerto. In its radiant solos, Daniel Majeske played with every bit of whimsy, of pure passiona, and of melting beauty suggested by the notes and their meaning. His final high note was to dream. He is to be soloist again in tonight's Barber Concerto.

It is quite a wrench to move from Strauss being heroic to Beethoven being heroic. But the Cleveland Orchestra has a long reputation for both composers, and both come off well yesterday. Maazel chose to omit the repeat in the first movement but the playing was flawless.