P a c i f i c M i c r o s o n i c s
D I G I T A L S O U R C E S
Pacific Microsonics Model Two
Company and Product History
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 few decades. Currently, (as of 2021), his designs for Spectral truly represent the state-of-the-art in playback component design. The incredible Spectral DMC-30SV Series 2 line preamp as well as the Spectral DMA-500SV mono power amp exemplify the heights of sophistication of design as well as the sonic beauty and reaslism that have been acheived. 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 2021, there still is nothing that sounds as good and as natural. 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.
Why is the Model Two out of production?
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:
"The HDCD converters were discontinued because it became impossible to build any more. When several critical components became obsolete, Pacific Microsonics made a 'last time buy' of as many of them as possible to allow production to continue for another year or two, as well as buying a large number of other components that were expected to go obsolete during that time period. All of them did go obsolete. So, at the end of that time period, it was then completely impossible to build any more. It would have required such a significant redesign that it would have been better to start from scratch on a completely new design.
However, by that time, Pacific Microsonics no longer existed and the converters were being built by Euphonix (by the same crew using all the same materials, test equipment, etc.). Keep in mind that the Model Two was never supposed to be a source of revenue for Pacific Microsonics. They were essentially sold at cost, and the company made money by selling the HDCD decoder chips to CD and DVD player manufacturers like Rotel and Denon. Since this did not benefit Euphonix, it was not practical for Euphonix to fund the design of a new version of the product. And as was pointed out, Keith Johnson and the other designers were busy with other work anyway and would not have been available.
BTW, although it is not possible to build new HDCD converters, Euphonix has a significant stock of service parts so there is no problem getting one of these converters serviced.
And yes! Keith Johnson's recordings are absolutely amazing. Check out anything he has done on Reference Recordings. He's also just about the nicest guy you'll ever meet."
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 Pacific Microsonics released their Model Two 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 after using it personally, 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 ext. 14 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 ext. 14. 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 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.
Model Two - usage tips
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.
Tip: If you have to change a previously made recording from a sampling rate of 48 kHz (or multiples thereof such as 96 or 192) to 44.1 kHz (or a multiple thereof such as 88.2 or 176.4), or vice versa, then it is better to do so through D/A and A/D conversion. The reason is that because the Model Two has such high quality A/D and D/A converters, the end result will be both sonically and musically more satisfying. While this may sound counter-intuitive to some people who are used to making such conversions using digital SRC (sample rate conversion) all you have to do is try both ways and hear the difference for yourself.
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 / 24 bit, 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 AES-EBU.
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 that can be utilized to set your levels.
A FEW NOTABLE PROJECTS RECORDED OR MASTERED WITH THE PACIFIC MICROSONICS MODEL TWO
Waltz for Debby - Bill Evans Trio
"In our decades-long study of the factors which are responsible for sound quality, my colleagues and I have found a number of key areas which must be addressed. First, it is critical to recover as much information as possible from the tapes, since detail lost at any stage can never be restored at a later stage. We use only top quality tape transports (highly tweaked Ampex ATR-100's and Studer A80's) matched with custom playback electronics from ATR Service or Tim de Paravicini. The playback electronics that came with these decks years ago just don't compare to the audiophile grade electronics we've all gotten accustomed to in our systems. The custom electronics that we use recover much more musically meaningful detail, more spatial cues, and more texture and three-dimensionality than the stock electronics.
"Decisions about any potential rebalancing or sonic restoration are made in acoustically treated rooms equipped with highest-quality audiophile playback systems. Any circuitry in the signal path, as well as cabling and AC power, are chosen for sonic performance. At the crucial step of analog to digital conversion, we have chosen the Pacific Microsonics Model Two ( designed by the legendary Kieth Johnson of Reference Recordings fame ). As important as all this is, there are two even more important parts of the puzzle: first, the experience and judgment of the mastering engineer in deciding when to adjust something and when to leave things alone. Second, our commitment to work as hard as necessary, and to avoid any shortcuts which might compromise quality.
"For instance, when both a 96K file and a 192K file are called for, it would be faster and more efficient to transfer it once, at 192K, and use a file conversion utility to convert it down for the 96K file. The file conversion programs are pretty good these days. Are they 100% as good as a direct transfer? This is a question we lose no sleep over. We take the extra care; we wind the tape back to the beginning, reset the capture system to 96K, and transfer it again. It's more work, but the result is something we can stand behind unequivocally. This commitment to do whatever it takes to get you the highest quality listening experience is at the heart of the Stubb-U-Sonic(™) principles." -Paul Stubblebine, remastering engineer Note: This Waltz For Debby file is available for purchase and downloaded from HDTracks.com