Saul B. Marantz, whose pioneering audio equipment made his name synonymous with advances in high-fidelity music systems, has died at the age of 85. Marantz died Jan. 16 at the Somerset Medical Center in Somerville, N.J. The cause of death was not released.“He was always, always tinkering with stuff,” said his daughter, June M. Chamberlain. That tinkering led to the establishment of the Marantz Co. in the early 1950s. The company produced record players, amplifiers and speakers that became industry standards. Marantz sold the company in 1964 to Superscope Inc. and stayed on as president until 1968. He later co-founded the Dahlquist Co., which built loudspeakers, and in 1986 became a partner in the Lineage Corp., a producer of top-of-the-line hi-fi systems. He was president of Lineage until his death. In addition to his daughter, Marantz is survived by a brother, a sister and three grandchildren.