All in a golden Philadelphia afternoon, Eugene Ormandy yesterday conducted the Philadelphia Orchestra and Benita Valente in the world premiere of David Del Tredici's "All in the Golden Afternoon."

The latest in the series of large works the dazzling young composer has written under the inspiration of "Alice in Wonderland," the "Golden Afternoon" takes its title from lines Lewis Carroll wrote as the preface poem of the published version of his famous story. One of its precedessors, "In Memory of a Summer Day, last year won Del Tredici a Pultizer Prize. "

The new work is filled with an ecstatic radiance recalled by the lines, "All in the golden afternoon full leisurely we glide."

Del Tredici has used repetitions of the seven-verse poem for his text, giving the soprano rhapsodic phrases that reach beyond two octaves in melodic turns that suggest Richard Strauss much as does the opulent scoring. The outsized orchestra's percussion battery includes his bird calls and even a wind machine, producing sonorities that are reminiscent of Strauss even while they speak with a voice that is peculiarly its owner's.

The 35-minute tone poem, in which at times the musicians in the orchestra provide a spoken chorus, is an outpouring of sheer beauty, a fantasy of exquisite nostalgia. Commissioned by Ormandy and the Philadelphia Orchestra, with a grant from the Atlantic Richfield Foundation, it was performed with ravishing effect. Valente sang like an angel of beauty. The composer seemed as happy with the performance as he should have been. It is a remarkable tribute to Ormandy, who at 81 continues to affirm strongly his belief in the wonders of today's newest music.