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Equipment Review

May 2004

47 Laboratory Model 4704 PiTracer CD Transport

by Marc Mickelson


Review Summary
Sound "Self-effacing, portraying music with poise and intimacy"; "the PiTracer displayed remarkable proficiency at reproducing low-level and inner detail" and it "heightened the contrast between transients and the musical mix from which they emerged"; but more than anything else, the PiTracer "excels at presenting music as a complete entity, not merely an amalgam of sonic qualities."
Features "A radical design" -- "its nearest relative...is an analog turntable, which also isolates the mechanism that spins the disc from the mechanism that extracts musical information." "PiTracer addresses [off-center CDs] with a specially designed moving head mechanism that reportedly reads a CD's pits with the laser at a constant 90-degree angle to the disc." Uses a separate 47 Lab Power Humpty power supply.
Use "The PiTracer's remote control is a cheap and flimsy generic plastic rectangle," and its "display is a small LCD type that can't be viewed in a darkened room at all or in a well-lighted room from more than three feet away." "Of greater concern, however, was mistracking that occurred with a few CDs," which could be a problem with the "well-traveled [review] unit."
Value "The $25,000 spent on a 47 Laboratory PiTracer buys both a lot of musical bliss and a bit of functional disappointment. Which is more significant is for you to decide."

Among manufacturers of audio electronics, a diverse lot to be sure, 47 Laboratory stands out. This small Japanese company produces decidedly uncommon products that nonetheless have quite a following. 47 Lab electronics are physically small, in contrast to the big boxes that most North American companies produce, and employ many purist touches, such as exceedingly short signal paths and separate power supplies (comically named Power Humpty and Power Dumpty). A few years back I auditioned a 47 Lab digital combination consisting of the 4713 Flatfish transport and 4705 Progression DAC (both deriving power from a single 4799 Power Dumpty). The sound was wonderful -- in some specific ways the best digital sound I had heard.

But this earlier brush with 47 Lab digital equipment didn't prepare me for the company's Model 4704 PiTracer CD transport. I feel confident in saying that there is not another digital product quite like the PiTracer. First, it costs $25,000 USD, which represents the uppermost reaches of current CD-transport pricing. Second, its method of extracting data from CDs is unlike that of any other CD transport made today. A way of summing up the PiTracer is to say it's like a conventional CD transport turned inside out -- much of what normally happens inside the chassis is out in the open for full view.

But even so, the PiTracer has the same functional goal of all CD players and transports: to read faithfully the digital data on a CD. CD players and transports do this rather like the mechanism that reads data from the hard drive of the computer you're using right now. Data is data, so the old saw goes, and therefore all a transport has to do is extract it from the disc and send it along to the digital-to-analog converter, where it's turned into an analog signal. Theoretically, the sound of various transports shouldn't vary for the same reason that identical data read from two different hard drives should be identical -- it's digital data, a static series of 1s and 0s. However, we audiophiles know that transports sound different, perhaps because of the way some deal with jitter-induced timing errors in the datastream, perhaps because of the differences in their power supplies.

Or perhaps because CDs are not perfect. Some are slightly off center, while others are severely so, making them more difficult for the transport to read. PiTracer addresses this with a specially designed moving head mechanism that reportedly reads a CD's pits with the laser at a constant 90-degree angle to the disc. According to 47 Lab, the PiTracer compensates for off-center CDs not by changing the angle of the laser, as conventional CD players do. Instead, the entire head unit, which houses the laser, moves over the top of the CD, which is tightly clamped to an acrylic platter, maintaining the 90-degree relationship to the CD and adjusting to any centering anomalies too. This is an ingenious solution, and one that took Junji Kimura, the design mind at 47 Laboratory, ten years to devise and perfect. It's also why the PiTracer costs $25,000 USD -- it's a radical design that prohibits mass production.

There are three main parts to the PiTracer: the platform on which the CD spins, the moving head unit, and the power supply. Each is isolated from the other -- another design goal. The chassis elements of the platform and head unit are machined from aluminum billets to add mass and cut down on vibration transferred from the spindle motor to the laser. The power supply, a 47 Lab Power Humpty, is housed in a round aluminum case about the size of a large can of tomato juice. It powers the platform and head unit via separate umbilicals. For maximum sound quality, you can use one Power Humpty for the platform and another for the head unit, a trick that will cost you $1800, the price of an additional power supply.

The head unit moves over the platform on highly polished wheels, these guided by highly polished rails. Both the wheels and rails are manufactured to very high tolerances by Bishop-Wisecarver, a California-based company that specializes in "guide wheel technology." The head unit's movement is controlled by a series of gears, including a worm gear that you can see fluttering away as a CD is playing to correct for any off-centeredness. With most CDs, this gear jerks quite a lot (just watch the small dot on top of the worm gear to see how much), but with some that are nearly perfectly centered, its movement is barely more than a minute quiver -- and in a few cases nothing at all. The head unit is connected to the mechanism that controls its movement by a special Kevlar-core thread chosen because it doesn't stretch over time.

There is much more that can be said about the design and manufacture of this fascinating and unique product, and there's a paper online that spells out most of it. Visit the website of Sakura Systems, 47 Lab's US distributor, to read further. Even if you think that PiTracer is the CD transport that Rube Goldberg would build, it's hard not to respect the originality of its design.

Connection and use

The system in which I used the PiTracer included components whose prices are similarly stratospheric: Wilson Audio WATT/Puppy 7 and MAXX Series 2 speakers, Lamm ML1.1 and M1.2 Reference mono amps, Atma-Sphere MA-2 Mk II.3 mono amps, Lamm L2 Reference preamp, and Atma-Sphere MP-1 Mk II preamp. For decoding duties, I connected the PiTracer to a Zanden Audio Model 5000 Mk III DAC via i2digital X-60, Stereovox HDVX or DH Labs D-75 BNC-terminated digital cables. As I've remarked in past reviews, the Zanden DAC sounds its very best connected from its BNC output to a BNC-equipped transport, no matter the digital cable. The PiTracer comes equipped with pairs of one RCA and one BNC S/PDIF digital output. One pair is AC coupled (for use with most DACs on the market today) and the other DC coupled (for use with 47 Lab's own Progression DAC). All outputs achieved lock with the Zanden Model 5000 Mk III, so I switched between the two BNC outputs for my listening. Don't ask me which sounded better -- I can't say.

Shunyata Research power cords were in liberal use -- Anaconda Vx and Anaconda Alpha, original Taipan and Python -- as was the company's Hydra Model-8 power conditioner, into which I plugged everything, mono amps and all. Interconnects and speaker cables were also from Shunyata Research (Aries and Andromeda), but Nordost (Valhalla) and Siltech (Signature G6 Forbes Lake and G6 Eskay Creek) cables were also used. The PiTracer sat either on a Townshend Seismic Sink that itself rested on a sand-filled Bright Star Big Rock base, or one of Harmonic Resolution Systems' gorgeous aluminum-and-granite M3 isolation bases, with which I preferred it. For comparison, I used a Mark Levinson No.37 transport, which also rested on the Seismic Sink/Big Rock combo or the HRS base.

Using the PiTracer is more involved than the drop-the-disc-and-push-play rhythm of using just about any other CD player or transport. With the PiTracer, you put the CD with its face side up onto the unit's acrylic platter, affixing it with the matching acrylic clamp that screws to the PiTracer's spindle. Push the top-mounted play button and you're off, although the head unit takes a few seconds to move into place before any sound emanates. This all probably sounds like more work than it is -- it becomes second nature pretty quickly.

However, I do have some serious criticism of two of the PiTracer's features. First, the transport's display is a small LCD type that can't be viewed in a darkened room at all or in a well-lighted room from more than three feet away. It is therefore of no use unless the transport is right next to your listening seat. Second, the PiTracer's remote control is a cheap and flimsy generic plastic rectangle. Yes, it controls the transport adequately, but it's utterly insubstantial. The display and remote are not befitting the PiTracer's $25,000 asking price -- or even a small fraction of it. I expected more.

Of greater concern, however, was mistracking that occurred with a few CDs. Most of us have taken for granted that CD players and transports nowadays will track any disc inserted into them, and that's because in essentially every case they do. Not the PiTracer, which emitted an audible series of static-like clicks or simply refused to play two or three CDs with which my reference Mark Levinson No.37 had no trouble. These discs showed no visible signs of mishandling -- no scratches or other blemishes. This problem could be a matter of the PiTracer sample sent to me for review -- a well-traveled demo unit -- showing some signs of wear and tear that a brand-new PiTracer would not. It tracked flawlessly every CD-R I listened to, something that is the Achilles heel of other CD players and transports. Even so, I once again expected more.

Words don't fail me

Over the course of my time as an audiophile, I've owned a few exceptional CD transports, including both Wadia 8 and 20 models as well as my current reference, a Mark Levinson No.37. These transports didn't sound identical, but all were designed and manufactured to very high standards and performed better than other models I was able to audition, even those that cost much more money.

Given the experience that comes from owning other high-performance transports and especially the operational issues I encountered with the PiTracer, I was not hopeful when I put the first CD onto the acrylic platter and secured it with the screw-down clamp. I had a backlog of negativity to overcome, but I take seriously this job of reporting on the sound a component produces, so I cleared my mind as best I could and began to listen.

I can't say that with those first few CDs I was knocked out by the PiTracer's sonic presentation. There was no immediate sense of wow and wonder, no fireworks or razzmatazz. Instead, the PiTracer's sound was self-effacing, portraying music with poise and intimacy. The sound was very liquid, and the PiTracer displayed remarkable proficiency at reproducing low-level and inner detail -- the sorts of things that more boisterous components don't do as well because they lack the refinement necessary to capture such subtleties. As I observed about the Atma-Sphere MA-2 Mk II.3 amps I reviewed earlier this month, the PiTracer excels at presenting music as a complete entity, not merely an amalgam of sonic qualities.

Nonetheless, I'll talk a bit about sonic qualities -- they're what I have at my disposal for describing the PiTracer's overall performance. I noticed right off that with the PiTracer in my system, transients had more snap. However, this was not a matter of a presentation that emphasizes the leading edge of notes. Instead, the PiTracer heightened the contrast between transients and the musical mix from which they emerged, sounding both unforced and lively. This was most apparent with up-front and highly detailed recordings such as Buddy Guy's Blues Singer [Silvertone 01241-41843-2], but even with the more subdued …And Serenity [Sony Classical/Legacy SK 90538], a compilation of Glenn Gould solo-piano performances, the PiTracer presented the music with both ample ease and abundant detail. Its sound was quickly addicting.

In keeping with this, strings, brass and especially cymbals had a delicate, shimmering quality that exposed the sophistication of the PiTracer's treble. And in the midrange, the PiTracer rendered voices with this same quality -- not a tubey sweetness or fullness, but instead a mixture of fine detail and low coloration. Actor John C. Reilly's voice on "Mr. Cellophane" from the soundtrack to the movie Chicago [Epic/Sony Music Soundtrax EK 87018] was beautifully resolved amidst strings whose overtones seemed to decay forever and a panoramic soundstage. The same goes for Victoria Williams' fragile voice on "Moon River," from her recent collection of covers Sings Some Ol' Songs [Dualtone 80302-01126-2]. Here, though, there was also a good deal of natural reverberation from the space in which Williams sings. The PiTracer captured it all, and presented it as an unpretentious and continuous soundfield, albeit one with certain characteristics that are so well done that they are nearly impossible to ignore.

I never completely grasped what pace, rhythm and timing sound like until I heard the PiTracer in my system. These are not a matter of tighter or weightier bass, for instance (in these strict terms, the PiTracer falls a bit short of other CD transports I've heard); instead, the music's rhythmic elements are more naturally paced, less choppy and mechanical. Ani DiFranco's Evolve [Righteous Babe RBR030-D] sounded funky and propulsive via the PiTracer, but there was more to the reproduction of this music than that. The bass was neither overwhelming nor anemic, so there was little to which I could call attention. Instead, it just sounded right -- flowed at the right pace along with the rest of the music.

Again, I think this has to do with the wholeness of the PiTracer's performance, as though every sonic element is present and in proper proportion. To use a visual analogy, a color copy can look very good, but you can always tell in some way that it is a copy -- the matrix of dots that make it up is detectable even without a loupe. The original is what it is -- the real thing. The PiTracer sounds like the original; there are no dots but rather the flow of true, saturated colors that constitute the image. This makes the PiTracer very easy to listen to -- it sounds human and has soul -- but difficult to capture with words. You'll know it when you hear it, however.

37 vs. 47

When comparing the PiTracer to the Mark Levinson No.37 ($4500 when available), I considered not only the over-$20,000 disparity in terms of their prices but also how different the two are functionally. I won't go into the No.37's circuit highlights, but I will point out that the No.37 is a joy to use. Its display is large and easily readable from 20 feet or more (it's adjustable to four levels of brightness, including completely off). Its remote is well made and heavy, and its commands always hit their mark. The No.37 is a classy package, and while the PiTracer certainly isn't chopped liver (it's a more openly creative design than the No.37 and essentially all other CD transports on the market today), it's not nearly as user friendly as the No.37, which also tracks every disc inserted into it, even those with minor damage.

However, sound is a different matter, and in this regard, listeners who believe that CD transports either don't sound different at all or have only subtle sonic differences should hear both the PiTracer and Mark Levinson No.37. It's shocking to discover how distinct these two transports sound.

It's hard to fault the No.37 for its conspicuous resolution -- its detailed and somewhat showy presentation. Images from the No.37 are large and prominent (but their outlines are not as strong as those of the PiTracer). The No.37's soundstage is larger and airier, leading to a more grand presentation. There are even sharper leading edges -- cymbals in particular have a crisper, more tinny sound -- and chunkier bass. In short, just about all of the traits we audiophiles value are addressed in a positive way by the No.37.

However, the No.37 lacks the PiTracer's wholeness, which leads, at least to my ears, to a less involving and enjoyable presentation. One track I listened to that showed this well was "Crowded Town" from astroPuppees wonderful Pet [HighTone HCD 8105]. SoundStage! named this collection of finely crafted pop art one of the best recordings of 1999; if you are looking for a fix between Fountains of Wayne albums, give Pet a listen. On "Crowded Town," a cover of a Marshall Crenshaw tune, the guitar in the right channel sounded more evident through the No.37 and also less integrated, giving the presentation something of a disjointed character. Through the PiTracer, that guitar, all other instruments and the singer sounded cohesive and whole -- as though there was some connecting element of the music that the No.37 was missing, a sort of sonic mortar. The No.37 certainly didn't make this track sound wrong, but the PiTracer made it sound more right.

I own the No.37, and I will continue to use and enjoy it. But I wish it sounded like the PiTracer.


The 47 Laboratory Model 4704 PiTracer is an inspired piece of audio equipment. Its nearest relative in terms of design is an analog turntable, which also isolates the mechanism that spins the disc from the mechanism that extracts musical information. But the PiTracer is a CD transport, and one whose goal of maintaining a 90-degree relationship of laser to disc only adds to its complexity -- and may be responsible for its terrific sonics. The PiTracer's sound is an amalgam of ease and inner detail, a refined treble and midrange, and bass that flows in a natural, unshowy manner. None of these, however, overshadows the effect of the PiTracer's overall presentation, which is complete and involving.

Would I buy a PiTracer if I could afford one? When I consider PiTracer's functional deficiencies, its $25,000 price is obscene (I chose this word carefully). But as I listen to music with the PiTracer, the definition of obscenity becomes cloudy. The PiTracer is the best-sounding CD transport I've heard by no small margin, and it represents a very enjoyable way to listen to CDs for those who have the considerable means required to buy it. That isn't me, but it may be you.

In the end, the $25,000 spent on a 47 Laboratory PiTracer buys both a lot of musical bliss and a bit of functional disappointment. Which is more significant is for you to decide.

...Marc Mickelson

47 Laboratory Model 4704 PiTracer CD Transport
Prices: $25,000 USD with one 4700 Power Humpty power supply; additional Power Humpty power supply, $1800.
Warranty: Five years parts and labor for Power Humpty power supply, two years for PiTracer CD transport.

US distributor:
Sakura Systems
2 Rocky Mt. Road
Jefferson, MA 01522
Phone/Fax: (508) 829-3426

Website: www.sakurasystems.com

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