According to a German company which specializes in booking American orchestras into European venues, the Pittsburgh Symphony Orchestra is planning two major tours of the continent in 2005 and 2006, despite not having a music director. The plans call for Hans Graf to conduct the PSO on the first tour, with Andrew Davis leading the way in late summer 2006. It is highly unusual for an American orchestra to tour without its music director, but the PSO may be attempting to take advantage of the worldwide reputation it earned under departing MD Mariss Jansons as one of the U.S.’s best, if not best-known, ensembles.