David West, noted guitar-amplifier builder and founder of West Laboratories, died November 10 in Dimondale, Michigan. He was 71.

West became noted amongst fans of ’70s rock and roll through his work with Grand Funk Railroad, for whom he built the all-tube/200-watt Fillmore model used by Mark Farner on the band’s first four albums and in live performance.

West’s first amps were based on vintage Fender models, which he had repaired and would dissect as part of his self-education. By the late ’70s, he had stopped building amps for a living, but continued to do so part-time while he operated the M.A.T. Music retail store, in Lansing. The store closed in the late ’80s, and West went to work as a computer programmer. In recent years, he was considering a re-launch of West Labs and had designed three prototype amps before experiencing health issues.

West is is survived by a daughter, Dr. January Suarez, and a son, Aaron.