Old and new from the Ailey troupe

The tried and true and a bit of the new - this makes up a fine program by any standard, and it's just the formula that brought the Alvin Ailey American Dance Theater into the New York City Center for its winter season, running through Dec. 20.

Even the Ailey company's newest audiences know that ''Revelations,'' a suite of spirituals, is a signature piece. When it appeared as the closing dance on the bill, the fans in the audience eagerly applauded each of its sections before they actually began. It was as if they knew ''Revelations'' by heart. Well, they probably do!

''Memoria,'' though only two years old, is already one of Ailey's tried and true dances. Dedicated to the late choreographer Joyce Trisler, ''Memoria'' is memorable for the lovely way it transmutes sorrow into jubilation. With a cast of thousands, it seems, ''Memoria'' ends as a massive celebratory chorale. The music is by Keith Jarrett, not Beethoven, but one can tell that Ailey means it to be his ''Ode to Joy.''

The two world premieres are slight by comparison, but one of them adds a nice swatch of humor to the Ailey repertory. ''Fontessa and Friends,'' by Louis Johnson, is a jolly hodgepodge of music and dance styles that ends up shooting down everything within range. That's where the hodgepodge factor enters most usefully. It broadens Johnson's range, enabling him to take in sights as various as a Charles Atlas muscle man and a sylph.

Using music composed by the Modern Jazz Quartet (including the title song, ''Fontessa''), Khachaturian, Scott Joplin, and others, ''Fontessa and Friends'' is conceived as a kind of vaudeville show. Fontessa, performed by Donna Wood in fabulous contessa style, is the mistress of ceremonies. The acts she presides over aren't nearly as classy as she is, and that's the point. Among the cast of characters are a ballerina and cavalier of genteel airs and dubious skill, a soft-shoe expert (wearing one green and one purple shoe), and a bunch of clowns wearing lots of ruffles and lots of bare skin.

The highlight of the show is the he-man act, set with a sharp, satiric eye to corny music by Khachaturian. It's a triangular love affair among Fontessa, the man, and his muscles.

The other premiere, by Ailey himself, wouldn't bear mention were it not for the specialness of the cast. ''Spell'' brings together for the first time two famous personalities of disparate worlds. Judith Jamison has been the longtime star of Ailey's company and is now on Broadway in ''Sophisticated Ladies.'' Alexander Godunov is a former star of Moscow's Bolshoi Ballet and since his defection two years ago has been a principal with American Ballet Theater. Both are famous for their electric presence.

Did ''Spell'' send off sparks? It didn't transmit any kind of spell, though it had all the trappings. There was Jamison in spectacular regalia of glitter and gold. Godunov wore shoulder-length hair and a Tarzan outfit. ''Spell'' was created as a fund-raising event - one time only, and it's probably just as well.