The precision instrument pictured here, wrought of cypress and cedar and waxed to perfection, is based on a 17th-century single-manual Italian harpsichord owned by the Smithsonian Institution. Robert Brooke, a computer programmer by day, built it in his spare time at home.

"I'm very happy with the way it turned out," said Brooke, who put the final touches on the harpsichord--including the nameboard and decorative moldings--a couple of weeks ago after working on it a year and a half. "I just hope I can keep saying that every new instrument I make is the best. This is my 10th since 1967."

So far, there have been nothing but raves from people who have played it. "I think it's first-rate," said Douglas Allanbrook, a harpsichordist who teaches at St. John's College in Annapolis. "It has a lovely, clear tone and a beautifully made keyboard."

This afternoon, J. Reilly Lewis, director of the Washington Bach Consort, will give the "Brooke" its professional debut. The Consort commissioned the $8,500 instrument to replace Lewis' personal double-manual French harpsichord for public performances. The inaugural work will be Bach's Partita No. 5 in an all-Baroque program at the Church of the Epiphany.