Junior Vasquez, born Donald Mattern in 1949 (some sources say c. 1946) in Lancaster, Pennsylvania, is a famous New York City club DJ and remixer/producer. Career Mattern moved to New York as a young adult in order to pursue a career in music production. His early work, in the 1980s, was under the guidance of notable disco DJ and pop remixer/producer Shep Pettibone. From 1989 to 1995, Vasquez gained national prominence — along with music industry influence — through his residency at the original Sound Factory