John Ulrick, formerly of Infinity, had been using Class D's since the early 70's. When I met first him he had recently started a company named 'Spectron' and they displayed their car audio line of speakers, regular amps reminiscent of AudioMobile, and their new 'digital' amps, as they were called, at the 1981 CES Show. The d's could be held in the palm of your hand. Those amps never made it to production and Spectron dropped car audio shortly thereafter and has since gone on to do rather well in home audio with their amplifiers.
