Marantz HDAM TechnologyMarantz developed its own discrete circuit boards to replace standard IC's. These HDAM's consists of discrete surface mount components with short mirror image L/R signal paths.
Those devices are doing exactly the same thing as the Op-Amps, but outperform the regular IC Op-amps dramatically in terms of the Slew Rate and reduced noise level, resulting in a much more dynamic, accurate and detailed sound. Over the years Marantz developed different types of the HDAM to improve quality and to fit to the special requirements of a product category like CD or amplifier.