When he lays down his baton after Friday night's concert with the National Symphony Orchestra, conductor Max Rudolf will retire from a distinguished career that has enriched American musical life since 1940, when he already had a well-established reputation in Europe. Last night, opening this week's concerts in the Kennedy Center Concert Hall, he demonstrated one of the primary skills of any performing artist; he left most members of the audience wanting more.

Rudolf was given a standing ovation at the end of the program, after bringing the Second Symphony of Brahms to a brilliant, dashing conclusion. It was a fitting tribute to a long life of distinguished service to music, although most of the audience was unaware of his impending retirement. Rudolf has long been held in special affection in Washington, not only by audiences but by many members of the NSO, who played for him with a special fervor last night as they have so many times before.

Last season, in the Washington Opera's "Magic Flute," he concluded a brilliant operatic career that had included many years of conducting at the Metropolitan Opera and the chairmanship of the opera department at Curtis Institute. Washington is honored this week to witness his second farewell performance.

There were moments that hinted at the weight of the conductor's 80 years, particularly the scaled-down dynamics in some passages and rather deliberate tempos in others. But both of the major works on the program--the Brahms Symphony and Beethoven's Fourth Piano Concerto--are amenable to such treatment, and it allowed some fine details of orchestral texture to emerge as they seldom do. There were also moments of great vigor and brilliance--the final movements of both works, for example, and the beginning of Weber's "Euryanthe" Overture, which opened the program. And the conductor's vision of the music's structure and meaning, his command of the orchestra, were always admirable.

Ivan Moravec, the piano soloist in the Beethoven, played with great finesse throughout and with a special romantic glow in the slow movement--one of the greatest and most vividly expressive in the concerto literature, with its contrast between the gruff, unruly orchestra and the quiet-voiced, persuasive piano. Rudolf coordinated the orchestral dynamics subtly with those of the solo. He always maintained a transparent texture, through which the piano's voice emerged with perfect clarity, without losing the drama of the orchestra's gradual acceptance of the quiet tone established and gently asserted by the soloist.

A special sense of drama was also evident in the opening movement of the Brahms (not seriously marred by a few moments of uncertain ensemble), and the sense of climax essential to the finale was beautifully conveyed. It ended this historic concert properly, not on a note of sadness but one of triumph.