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. Currently, (as of 2012), 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. If you'd like to learn more about Keith here is a link that explains his recording techniques and what kind of recording equipment he uses to achieve the high level of sound quality for which he is so renowned. If you'd like to hear his recordings here is a link to Reference Recordings and also a direct link to the high resolution HRx files which are bit-for-bit copies of the 176.4 kHz/24 bit stereo master recordings made with the Pacific Microsonics Model Two. If you would like to learn how to play these HRx files click here. There is also an interview in the February 2009 Absolute Sound which is quite interesting in which he talks about his approach to the design of high performance audio components.
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. Currently, as of 2009, he is part of the new Berkeley Audio Design team which manufactures 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.
A few years later the Model One was replaced by the Model Two which—in addition to 44.1 and 88.2—added in 48, 96, 176.4 & 192 kHz sampling rates. For those top recording and mastering engineers who are fortunate enough to be using them, they know that the Model Two was, and still is, the best A-D converter ever made. And even though it is now discontinued, as of 2013, there still is nothing that sounds as good and as true. For the true test of an A-D and D-A converter combo is to first listen to a high quality live mike feed of acoustic music and then to insert the A-D/D-A combo and listen to the degree of difference. Especially if you are listening through a very neutral, linear, top notch high end audio system properly setup in a room with excellent acoustical treatment, you will hear and understand for yourself. Alternatively you can do the same test with a high quality analog master tape as the source. In our experience the Model Two operated at 176.4/24 or 192/24 is simply the closest thing we've heard to a live mike feed.
● Pacific Microsonics Model Two A-D/D-A Converter
Here is some information about the Pacific Microsonics Model Two:
● Model Two - usage tips
When making a new recording using the Pacific Microsonics Model Two consider how it will be released.
If a CD will be made from the recording then it is best to make the recording at 176.4 kHz / 24 bit. That way you can get a perfect decimation down to 44.1 kHz. (In this case the perfect decimation is 176.4 divided by 4 = 44.1). Also that way you have the highest quality master recording which can, if you so choose, be released as a high resolution file. High Resolution files can either be sold on-line as a download or distributed on a medium such as DVD-R.
If a CD will not be released of the recording then you could make it at either 176.4 or 192 kHz, as the sound quality at either sampling rate is essentially indistinguishable from each other. Once again, if there is a reason to down-convert, think about always trying to do so with perfect decimation (using the Model Two to do the down conversion) when doing so in the digital domain.
When using the Model Two to do a recording, it is best to set the Model Two as the Master Word Clock and slave the recorder to it. The reason is that the Model Two contains a highly accurate word clock and you will get the best sonic results this way.
When using the Model Two at either 176.4 or 192, you will need to hook it up to a digital recorder using dual-wire AES-EBU. However if your recorder will not work with dual-wire then you can use it at 88.2 or 96 using single-wire.
The most efficient way to switch modes is to use presets which can be custom setup in order to be optimized for your recording rig.
To set the recording input level: There is a removable plate on the rear panel, behind which is a set of jumpers which you use to set your levels.
● Why is the Model Two out of production?
Everyone who hears the Pacific Microsonics Model Two of course immediately asks the question, "Why it is no longer available?"
Here is the answer written by Dave Peck, who formerly worked for Pacific Microsonics and now works for Euphonix (which continued the manufacturing of the Model Two after Pacific Microsonics was acquired by Microsoft), and was intimately involved with the manufacturing and testing of both the Model One and the Model Two:
Because of Alan Goodwin's passionate interest in recording acoustical music at the highest level of quality possible, he spent many years waiting for an A-D converter to come along which sounded really good. But after owning and recording with a Studer A80-RC fitted with Levinson electronics, for many years digital just didn't sound as good and so he kept searching and waiting. Finally the Pacific Microsonics released their converter and the search was over. His assessment at the time was, and still is, that the Model Two meets the highest standards of both high end audio and professional audio—which makes it relatively unique as very few products actually do.
Initially his search was only for a converter that he could use for his own recordings. However with the Model Two being so superb, and because he felt that he understood the product so well and that it met his personal standards of excellence, he felt that he should represent such a superb product. Also because he knew Keith Johnson and other insiders involved in the project he became the East Coast dealer for the Model Two.
His view is that it is a crime against music that the Model Two is no longer in production! (Now the preceding sentence may sound a bit melodramatic—but the proof is in the listening.) Because today most people listen to music through digital recordings—once Analog-to-Digital conversion is done at a lower level of sonic quality, it can never be improved upon. Maybe someday someone will come up with the necessary funding (which as it turns out would be several million dollars) to start another company, re-engineer the Model Two around parts that are either attainable or buildable, and put it back into production. If you are interested in funding such a project please call Alan Goodwin at 781-893-9000 sooner rather than later as each year that goes by makes it more challenging to accomplish for several important reasons. In the meantime, if you have one you know how lucky you are!
If you are seeking a Model One or Model Two you can contact Alan Goodwin at 781-893-9000. Though they are no longer in production, because he was the East Coast dealer he knows where many of them are. So he might be able to search for and locate a used one for you—or arrange for a rental for you for a special project where sound quality is of the utmost importance and nothing else will do.
● Recording and Mastering Engineers using the Pacific Microsonics A-D/D-A Converter:
If you have a recording or mastering project that is especially important to you, here is a partial listing of a few of the top Recording and Mastering Engineers who utilize the Pacific Microsonics Model Two:
Mastering & Recording Studios using Pacific Microsonics Model Two
Ø SAE Mastering - Phoenix, AZ - 602-242-0022
Ø Paul Stubblebine Mastering - San Francisco, CA - 415-522-0108
Ø Michael Romanowski Mastering - San Francisco, CA - 415-522-0108
Ø John Greenham Mastering - San Francisco, CA
Ø Rob Cross Mastering - San Francisco, CA
Ø Cohearent Mastering - Kevin Gray - San Fernando Valley, CA - 818-894-3400
Ø Mockingbird Mastering - Jeffrey Norman - Petaluma, California - 707-696-0616 (M-F 10-7 PST)
Ø Lou Hemsey Music and Film - Los Angeles, CA - 818-524-8545
Ø Air Show Mastering - Boulder, CO - 888-545-9035
Ø Gateway Mastering - Bob Ludwig - Portland, Maine - 207-828-9400
Ø M Works Mastering Studio - Jonathan Wyner - Cambridge, MA - 617-577-0089
Ø Focus Mastering - Doug Van Sloun - Omaha, NE - 402-504-9624
Ø Battery Mastering Studios - Mark Wilder - New York, NY - 212-833-7373
Ø Battery Mastering Studios - Tim Sturges - New York, NY - 212-833-7373
Ø Battery Mastering Studios - Vic Anesini - New York, NY - 212-833-7373
Ø Kitchen Mastering - Brent Lambert - Carrboro, NC - 919-929-4494
Ø Super Audio Mastering - Simon Heyworth - Great Britain - 44 (0) 1647 432 858
Ø Cutting Room - Stockholm, Sweden - 46 (0)8 505 817 00
Mastering & Recording Studios using Pacific Microsonics Model One
Ø Magic Garden Mastering - Brian Lucey - Columbus, OH - 614-620-4567
Ø Hit Track Recording Studio - Las Vegas, NV - 702-481-1663
Ø The Red Room - Philippe Weiss - Suresnes, France
Record Labels using Pacific Microsonics Model Two
Ø Reference Recordings - San Francisco, California
Ø Linn Records - Glasgow, Scotland - 44 (0)141 303 5027
Ø First Impression Music - Winston Ma - Seattle, Oregon
Pacific Microsonics Model Two Rentals
Ø Advanced Audio Rentals - Burbank, CA - Day Rate: $250 - 818-955-7100
DMT Rentals -
● A few notable projects recorded or mastered with the Pacific Microsonics Model Two
Additional HRx titles are viewable here.
Note: If you are a Bill Evans fan you will be happy to know that there are other 192kHz / 24 bit high resolution files at HD Tracks:
They are available in various different file formats including WAV and AIFF (which we prefer to either FLAC or ALAC). Also if you are interested in how to set-up a high end music server to play high resolution files with low jitter here is a link.
Here is another link re: Neil Young Greatest Hits
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