Knowing the Score at Playboy’s 15th Jam

Tip sheets have long been part of the sporting world. Who would think of going to see the ponies run without a consensus clipped from the day’s newspaper or a Racing Form tucked under their arm?

Well, here is a tout sheet for a jazz festival: the 15th Playboy Jazz Festival, being held next Saturday and Sunday at the Hollywood Bowl. With musical excellence in mind, The Times has assigned letter grades to the artists appearing at the festival. The grades range from A to C--there really are no duds, just some big question marks, on this year’s lineup.

Here’s how Saturday’s program, which runs from 2:30 to 11 p.m., stacks up:

* The L.A. Sax Giants: You have to assume that such esteemed improvisers as Harold Land, Bob Cooper, Teddy Edwards, Plas Johnson and Buddy Collette--who have never played together as a fivesome before--will come up with performances that are both refreshing and chock-full of unexpected delights. Grade: A

* Horace Silver: The pianist-composer’s Silver/Brass Ensemble delivers his newest portfolio of tunes, which, while pleasing enough, don’t reach the level of his classics, such as “Silver’s Seranade,” “Room 608” and “Senor Blues.” However, these days the jazz giant’s punchy piano playing is revitalized, and is as captivating as it was in the ‘50s and ‘60s. Grade: B+

* Wynton Marsalis: The trumpeter seems to be settling into a comfortable identity, steering his septet in the path first trailblazed by Duke Ellington’s small bands in the ‘50s, resulting in some of his best work ever. Strong soloists--pianist Eric Reed, saxophonists Walter Blanding and Wes Anderson, and trombonist Wycliffe Gordon--add substantial clout to Marsalis’ outings. Grade: B+

* The GRP All-Star Big Band: While this group--featuring such GRP notables as trumpeter Arturo Sandoval, pianist Dave Grusin and saxophonist Tom Scott--obviously lacks the finesse that comes from years of engagements and rehearsals, its renditions of tunes by Monk, Sonny Rollins and Dizzy Gillespie have, if nothing else, considerable zeal. Grade: B+

* Buddy Guy: Gritty guitar lines and vocals etched with a mixture of pain and joy mark this bluesman’s often gripping numbers. Grade: B+

* Mel Torme: The durable singer always centers his shows around the great American pop standards, though Torme’s versions are sometimes lacking in emotion, and thus, believability. Grade: B

* Dorothy Donegan: The Swing-based pianist, who loves melodies and can play fast, often indulges in crowd-pleasing hysterics--like dropping in far too many glisses--that distract from her musicality. Grade: B

* Ray Anthony: While the trumpet-playing bandleader had some pop success with tunes such as the “Theme From Peter Gunn” and “Slaughter on Tenth Avenue,” his lukewarm Swing Era stylings have never raised many eyebrows. Grade: C+

* The Rippingtons, with Russ Freeman: The guitarist’s band, which includes saxman Jeff Kashiwa, has been stuck in an overly soft, pop-jazz rut for too long, and needs more muscular, dynamic selections. Grade: C+

Sunday’s card, which runs from 2 to 10:30 p.m., grades out like this:

* McCoy Tyner’s big band: The pianist’s ensemble--outfitted with such ace New Yorkers as saxophonist John Stubblefield and trombonist Steve Turre--is a spark plug, shifting smoothly from brilliant numbers that seem always on the brink of an explosion to pieces more filled with murmurs than shouts. Grade: A

* Charles Lloyd: Introspective by nature, the saxophonist is back on the jazz horizons after a 10-year absence, delivering work that stresses the soft and the gentle without abandoning the hot. His quartet includes two splendid artists: Scandinavian pianist Bobo Stenson and masterful drummer Billy Hart. Grade: A

* Poncho Sanchez: The spirit that imbues the conga drummer’s Latin and be-bop tunes--ever underpinned by happy rhythmic babble--makes his performances come to life. His guests--fellow conguero Mongo Santamaria, timbalero Willie Colon and trombonist Turre--will add to the fun, though Sanchez’s own trombonist, Andy Martin, could steal the show. Grade: A-

* Roy Hargrove: The trumpeter--one of the best youngsters in jazz--is striving to find his own voice in the post-bop arena, and is getting there, though his compositions lack the craft and flavor to make them memorable. Grade: B+

* Zawinul Syndicate: There’s a teasing, unexpected quality about a Joe Zawinul performance. His current sonic world is inhabited by an amalgam of electronic, synthesized stuff and a trunk full of rhythmic fulminations, resulting in a metaphorical meeting of Weather Report and World beat musics, a la J.Z. Grade: B+

* Dr. John: Though the pianist-singer’s New Orleans-based effusions of his New Island Social and Pleasure Club don’t have much to do with jazz per se, there’s something so seductive about that Crescent City rhythmic charge that it doesn’t matter. Grade: B

* Les McCann and Eddie Harris: Revisiting their classic ‘70s hit “Compared to What?” the pianist and saxman will engage in outings notable as much for their fun as their music-making. Grade: B-

* Al Jarreau: He definitely has the voice, and he has the rhythm, but the singer’s decision to appeal to mass audiences via lower-common-denominator material has hurt him aesthetically. Grade: B-

* Patti Austin: If only the singer would apply her substantial vocal gifts to equally solid tunes, she’d be wondrous. Grade: C

Overall rating: Musically speaking, this year’s Playboy should be one of the best ever. Grade: B