MXR MXR was founded in 1972 as an effect pedal manufacturer. MXR was purchased in 1987 by Jim Dunlop, and is best known for its phasers, chorus', and other pedals. Founded:1972Founder(s):Keith Barr, Terry Sherwood Average User Rating 0 0 votes Please sign in to rate. Your Rating 0 Contact Phone Number: (707) 745-2722 Headquarters: Rochester, New York Email: Contact form Online: History History coming soon!