Pacific Microsonics HDCD Model 1

I am sure you know what this is if you have found it.

Pacific Microsonics invented HDCD which stands for High Definition Compatible Digital. They also designed the PMD100, and subsequently the PMD200, HDCD decoding chips. Because none of the existing converters were up to their standards, in order make the kind of sound quality that was necessary to enable HDCD to work up to it's full potential they also had to design an A-D and a D-A converter. The first A-D/D-A was the Model One. Later that was replaced by the Model Two.

The primary engineer in charge of designing the circuitry for the legendary Pacific Microsonics Model One and Model Two converters was "Prof." Keith O. Johnson. Keith Johnson is one of the top digital and analog electrical engineers in audio today and has been the lead designer for Spectral Audio for the past two decades. His designs for Spectral truly represent the state-of-the-art in playback component design. In addition Keith Johnson is a multi Grammy Award-winning recording engineer who also coauthored several patents covering optical-disc technology that are the basis of today's video discs and digital audio CDs. Previously Keith co-founded Gauss Electrophysics, where he invented the technology used throughout the industry that enabled high-speed, high-quality duplication of prerecorded audio tapes. There is much more that could be said about Keith and his long list of accomplishments, but suffice it to say that he is highly respected in the realms of both high end audio and professional audio.

Mathematician Pflash Pflaumer was another key member of the design team and was responsible for writing the DSP code—which are the very sophisticated algorithms used in the converters. Pflash is well known to those in computer networking as the inventor of TOPS, the first local area network that connected IBM PCs, Apple Macintosh, and minicomputers running UNIX. For more than three years, TOPS was the best-selling Macintosh network product internationally and earned Pflaumer several awards. Later, the company that he co-founded to develop TOPS was acquired by Sun Microsystems. As of 2009, he was part of the Berkeley Audio Design team which manufactured the highly popular Alpha One DAC.

Other key members of the team were Michael Ritter (Managing Director), Rene Jaeger (Design Engineer), Dave Peck (Manufacturing Manger), and Andy Johnson (Director of Engineering).

Initially Pacific Microsonics designed and manufactured the Model One A-/D-A converter which operated at both 44.1 and 88.2kHz—at 16, 20, or 24 bits.