John "Jack" Pfeiffer (September 29, 1920 -February 8, 1996),was a classical recording producer, a design engineer, and an occasional electronic music composer.
Born in Tucson, Arizona, Pfeiffer studied music and engineering at the University of Arizona and Bethany College in Lindsborg, Kansas. After naval service in World War II, he moved to New York, where he attended Columbia University and worked as a jazz pianist before joining RCA Records as a design engineer in 1949. Pfeiffer was best known as a producer of classical music. His reissues of the complete recordings of Arturo Toscanini, Sergei Rachmaninoff and Jascha Heifetz were critically praised and won several awards. The Heifetz Collection received a Grammy award in the historical category. Pfeiffer also recorded contemporary artists, including the mezzo-sopranos Marilyn Horne and Frederica von Stade, and Xiang-Dong Kong, a young Chinese pianist. Pfeiffer also produced recordings by the pianists Vladimir Horowitz, Arthur Rubinstein and Van Cliburn, the harpsichordist Wanda Landowska, and the soprano Leontyne Price. In addition to Toscanini, Pfeiffer worked with Fritz Reiner, Leopold Stokowski, Eugene Ormandy and Charles Munch, and produced their initial "Living Stereo" recordings.