Audio Dynamics Corporation, better known as ADC, was founded by Peter Pritchard in the early 1960's. ADC cartridges were based on the "Induced Magnet" design, a derivative of the older GE variable reluctance cartridges then invented by Peter Pritchard under GE patent. ADC cartridges are notable for their high compliance and low tracking force - exhibited by a series of very successful cartridges of exemplary performance and sound quality including the well-known ADC-10, ADC-25 and XLM cartridges. The latter became the reference of many audio enthusiasts including Harry Pearson during the early years of The Absolute Sound. After the sale of ADC in the 1970's, Peter Pritchard formed Sonus and produced the Sonus line of reference quality cartridges.