Marionettist Daniel Llords and the 12-year-old Mozart stole the show at The Barns of Wolf Trap Saturday night, when the Wolf Trap Chamber Players made their debut under conductor Miran Kojian. Llords' engaging production of Mozart's first opera, "Bastien et Bastienne," originally conceived for marionettes, echoed perfectly the freshness and charm of the young composer's music.

The opera contains fascinating foreshadowings of both the mature Mozart and, in the prelude, of the opening theme from Beethoven's "Eroica" Symphony. An able trio of former Wolf Trap Opera Company singers joined Llords in projecting with infectious good humor the simple drama of two lovers who quarrel and then make up. Soprano Virginia Boomer's polished sound and melodic finesse were particularly strong assets, along with the vocal assurance of bass Robert Ferrier and the pleasing timbre of tenor Rodney Miller. Llords capped a stream of theatrical inventiveness by introducing a wedding cake from a miniature trap door to serve as a platform for the reunited lovers. The cake rose in one tier after another to match their soaring bliss in the final duet.

Despite the obvious good will of the players, most of whom are fellow National Symphony members, conductor Kojian conveyed little more than the surface energy of the opening orchestral selections. Bach's Third Brandenburg Concerto needed more precise articulation and greater unity of ensemble sound. Haydn's Symphony No. 47 revealed Kojian's responsiveness to the grace of the classical style, especially in the second movement, but the intrepretation lacked backbone. The hall itself proved once again highly conducive to music on the chamber scale.