He made his debut with Symphony Silicon Valley in two sold-out performances in 2012, praised by the San José Mercury News as a “gorgeous performance; big, enveloping and wonderfully luxuriant.” His other appearances as a guest conductor in California include the San José Symphony, Santa Rosa Symphony, the Inland Empire/Riverside Philharmonic, Ballet San Jose, the California Riverside Ballet and the Livermore-Amador Philharmonic. Concerts elsewhere have included his return to Europe to guest conduct the New Polish Philharmonic and the Suddettic Philharmonic, concert tours of England, France, Spain, Italy, Germany, Austria, Czech Republic, Hungary, Belgium, the Netherlands, Japan, Australia and New Zealand with PYO, numerous return engagements to the San Jose Symphony (the predecessor of Symphony Silicon Valley), and his return to the podium of the Santa Cruz County Symphony. Prior guest conducting appearances have included the Seattle Symphony, New Polish Philharmonic, Suddetic Philharmonic, Richmond Symphony, Eastern Philharmonic, Flagstaff Festival Symphony, Amarillo Symphony, Lexington Philharmonic, South Bend Symphony, and many others. Maestro Klein also has extensive experience in conducting ballet orchestras, including the Kansas City Ballet, Lone Star Ballet, Oakland Ballet, and Westport Ballet, as well as the Theater Ballet of San Francisco and les Ballets Trockadero de Monte Carlo.