Most of this year’s planned tributes to Beethoven’s 250th birthday have been canceled due to the pandemic, so one welcomed the Sinfonietta’s contribution, which proved characteristically unorthodox. Rather than offer something wholly familiar, Chen led the Sinfonietta strings in Jeffrey L. Briggs’ arrangement of two movements from Beethoven’s Piano Sonata Op. 13, “Pathetique.” This may have seemed like a bit of a stunt, in that this music is so inherently pianistic. But there were new pleasures to be drawn from this arrangement. In the adagio cantabile second movement (mistakenly identified onscreen as the third movement), Chen conjured considerable tenderness and introspection. And in the last movement, the conductor took a slower tempo than pianists usually do, giving the music a degree of grandeur it rarely receives.