Perpetual Technologies P1A Digital Correction Engine/Upsampler and P3A Digital to Analog Converter
|Perpetual Technologies P1A Digital Correction Engine/Upsampler and P3A Digital to Analog Converter|
7 May 2001
The upsampler (P1A) costs $950;
The DAC (P3A), $699.
For product and order information:
The following is a combined review on the Perpetual Technologies P1A Digital Correction Engine (upsampler) and the P3A 24/96 DAC. Although both components can be purchased separately, Perpetual Technologies emphasizes the synergistic benefits of using the P3A to decode the upsampled signal from P1A. For example, via the I2S connection, the combo of P1A and P3A facilitates an upsampled quantization of 24-bit at 192kHz! Both products are available directly from the manufacturer with an unconditional 30-day guarantee.
By implementing what PT refers to as signal interpolation and resolution enhancement, the goal is to maximize the CD’s available resolution. This stated goal resembles comments in Stereophile’s review on the British dCS 972 upsampler and the Elgar converter in 1999. Briefly, the dCS 972 upsamples the conventional CD signal of 16-bit 44.1kHz to 24-bit 192kHz and sends it to the Elgar processor – a costly two-step process. With each component over $5,000, not too many of us can afford these benefits.
Another British high-end veteran company, Meridian, has an integrated CD player with internal 24/88.2kHz upsampling. To many, the search for the Holy Grail stops at this component, yet, for me, to invest in a CD-only transport at the present time makes little sense, unless it can also play SACDs.
In its July 2000 issue, Stereophile reviewed another one-box, upsampling player from Japan, the Accuphase DP-75V. It costs over ten thousand dollars. For the less affluent, another option for enhancing the CD’s resolution is the Wadia 270 transport matched to my Wadia 27 "ix" upgrade. The 270 costs $8,000, the 27’s "ix" upgrade, $1,750, total for the option, $9,750 plus tax. In comparison, Perpetual Technologies’ $1,700 combo of the P1A and P3A seems irresistible. From the information available on their website, it seems that PT has put a tremendous amount of R&D into the design of their initial offerings.
P1A + P3A
Audiophiles who have used Audio Alchemy products will instantly recognize these pieces. PT’s founder and President, Mark Schifter, was heavily involved in the designs of Audio Alchemy gear. His recent credentials include a partnership with Arnie Nudell of Genesis Technologies. The P1A’s chassis, though diminutive at 5.5" x 8.25" x 1.75" (WxDxH), is an eye-opener. Weighing in at a mere 4 lbs., it looks like an expensive jewelry box. The night I got home and opened it, I competed with my wife for first-touch. Imagine our luck with regard to WAF (Wife Acceptance Factor) if our dream systems’ looks appealed to our mates!
Inputs include I2S, AES/EBU, and Coaxial; outputs feature the same array. ST and Toslink are not available. Similar to other pieces of AA gear, the P1A comes with an outboard power supply, but unlike previous AA components, such as the DTI-Pro, the piece runs cool to the touch even after long hours of power-up.
Similar to other AA gear, the P1A’s front panel has only two buttons. By various combinations of steps, these buttons controls the input source selection, polarity inversion, output quantization selection and upsampling rate selection. While aesthetically satisfactory, the buttons’ operation was not as straightforward as one could wish. Provided that the minimum output settings of 24-bit quantization and 96kHz sampling rate is always desired, once the input source selection changes, the outputting quantization and sampling rate will both have to be set again. With only one provisioning input for each format, the audiophile who intends to connect his CD transport to the P1A via AES/EBU, his DVD player via Coaxial, and another machine via I2S, just for example, will have to go through the following steps each time he changes the input:
Input selection – Output Quantization selection – Output Upsampling Rate selection
Unless the user familiarizes himself with the controls by operating the buttons frequently, he’ll have to consult the manual often. In addition, the front panel provides setting confirmation with varying lights. I had to redo the settings just to make sure I went through the correct steps. A remote control would address these inconveniences nicely.
PT supplies two footers for vertical placement of the P1A. Alternate adhesive pads accommodate conventional horizontal placement. As shelf space is getting more and more precious at my house, I welcome this arrangement.
The P3A utilizes the same chassis as the P1A’s and has the same input array. It was shipped to me in late May after production started. With the P3A comes one half-meter I2S cable for receiving upsampled signals up to 24/192 from the P1A as part of the package. There is only one pair of analog outputs with no balanced option.
At the heart of this Digital Correction Engine is a SHARC chipset, a 32-bit floating-point processor. PT claims that it is versatile and powerful enough to be used for customized phase correction on speakers and customized room acoustics correction. Upgrades will be available for the P1A in the form of Internet downloads via a terminal on the rear panel. Each upgrade, when available, will cost approximately $300 to $400.
As for the P3A, according to my emails with Jon Lane (email@example.com), Perpetual Technologies’ Director of Technology, although upgrades are not planned at the present, another sibling, the P5A, a "balanced, differential version of the P3A with level control and available remote," housed in an entirely different chassis, will become available at $1,499. At that time, PT will offer "generous trade-ins" for its P3A customers.
Short Note on My system
My least expensive component is the Monarchy Audio SM-70, a small single-ended, no feedback, solid-state amp. At 25wpc, it is impractical in many high-end systems with speakers of low to medium sensitivity, but, with my Klipschorns’ 104dB sensitivity, a very proper match.
The original Wadia 27 dates from 1996, the "ix" 24/96 upgrade a later option. In the Wadia 27, the "direct connect" concept from DAC to power amplifier shortens the signal path, supposedly reducing signal degradation. Before the arrival of the Sony SCD-777ES, and the subsequent P1A+P3A combo, I used no preamp. A Krell KRC-2 went into the system to accommodate the P1A+P3A. I made comparisons between the P1A+P3A and the Sony SCD-777ES but will not include them here owing to the complexities involved and a need to be brief.
P1A to Wadia 27
The Wadia 27 is an elite piece of gear. Years spent listening to it could easily render out of proportion a perception of the smallest change in the soundscape. Prior to the emergence of the P1A and P3A, I exchanged emails with Wadia on the topic of upsampling technology. According to Wadia, their proprietary 64-times oversampling in the Wadia 27 is "mathematically synonymous" with upsampling to 24-bit 96kHz. Food for thought. This aspect will be dealt with in greater depth in tentative Wadia 27 review. Meanwhile, I have no means to dispute such a claim, but it does help to explain why that Wadia, one of the premiere architects of the digital audio world, has not released an upsampling machine.
The P1A was initially connected to the Wadia 27 via the Audio Alchemy DST Transceiver in XLR for a month before the P3A became available. In this arrangement, the P1A confirmed an output word length of 24-bit with the Wadia receiving. The Wadia also was able to accept 48kHz-upsampled rate at the maximum. So, 24/48 it was!
During that period, compared with the ST direct connection from the CEC TL1 to the Wadia 27, I noticed a very minimal amount of improvement with P1A in the link. When playing CDs made in the mid 80’s, the P1A softened the brittle vocals a little; I noticed no difference when playing CDs from Telarc. On more recently remastered recordings, like the "Original-Image Bit-Processing" from Deutsche Grammophon, instruments from the Berlin Philharmonic were rendered more three-dimensional, at least to a degree.
Improvement there was, but it certainly couldn’t justify, for me, the $1,000 investment. I sent an inquiry to PT. The following is an excerpt from Jon Lane’s reply to my email:
"Empirically, we know that many DAC’s , including some very expensive units with ‘24/96’ advertised, simply do not have the noise floor to thoroughly allow all 24-bit data to be throughput unscathed. That is, 24/96 DAC’s may actually possess 110dB of s/n thus rendering them something like practical 18 bit machines, not 24. Our little P-3A DAC, by the way, features in excess of 140dB of s/n and thus qualifies as a near-24 bit machine, with -144dB being theoretical for 24 bits.
"I would question whether the associated equipment – while excellent in its own right – is suitable. Without a -140dB s/n in your DAC you will not benefit from 24-bit data. Further, the 48kHz limit in the Wadia is also reducing the system's total capabilities, at least on paper. I would never disparage the Wadia name or product, but I must say that Perpetual Technologies digital components are simply revolutions in the digital world: very leading edge design and extraordinary value. We are breaking the mold of limited production, expensive high-end equipment with our very high volume, direct business model. The P-1A/P-3A combo, at around $1500 [MSRP $599 until May 31] is far beyond any system combination we've ever compared ourselves to that is over a year or so old at virtually any price save only the Levinson (also SHARC-based). The digital landscape is changing radically due to advances in chipsets, affordable software-based systems on a single CPU, and volume manufacturing. Due to these differing philosophies, it may be wise to evaluate the two complete systems side by side rather than trying to marry one to the other."
In short, my Wadia 27 might not be up to the task! The owner’s manual doesn’t list the s/n ratio, only the mips and resolution in bits. My inquiries to Wadia have not been answered. Although "excellent in its own right," the Wadia 27 is not a synergistic match for the P1A; the P3A is.
"High resolution" was the first thought that came to mind. Imaging and microdynamics are the combo’s real forte. Truthful to the upstream signal, the effect of P1A and P3A’s 24/192 upsampling depends on the quality of the CD. Furthermore, after listening to CD after CD, I was consistently reminded of the different priorities different audiophiles have and how these could affect their appreciation of this combo. In my rectangular 12×17×8 (W×L×H) listening room, at both corners of the shorter wall, my toed-out Klipschorns have been recreating a considerably large soundstage. I shall elaborate on this in a future Klipschorn review.
Playing regular classical CDs – Deutsche Grammophon, EMI, Sony, Orfeo, etc. – imaging was precise. I heard a higher level of energy concentration at the center. In better recordings, this characteristic rendered instruments in better focus. Front-to-back perspective came across with respectable depth and localization. Excellent microdynamics helped in portraying background instruments as onstage in relation to the highlighted players, with, throughout, an excellent portrayal of timbre. When it comes to these, the P1A and P3A demonstrated an interesting aspect of their personality.
Realistic dynamics are the strength of my horn system. The P1A+P3A consistently squeezed out every drop of dynamic juice, making me feel part of the music-making experience. When the orchestra’s brass section soared, the sound resembled that of a live performance.
Vocalists likewise sounded better. I heard no extra definition to soprano and tenor voices, and yet they sounded cleaner. Somehow the singers appeared lower in stature, as if sitting, a consistent perception whether I played a studio or live concert performance. The distance between mouth and microphone appeared to have diminished as well.
Bass drum definition was excellent, control of loudness exceptional. As the instrument that creates the lowest octave in the orchestra, the bass drum was carefully rendered with good edges. On better recordings, its role rose to a higher status.
Woodwinds came through with clarity coupled with a delicate touch. The fragile yet pronounced high notes they created were given enough strength and air, making them befitting as subtle yet vital pieces of the big picture. Cymbals sounded uncompressed, with excellent ambiance and spaciousness.
Pianos exhibited impressive body and tone. Most interesting was the instrument’s loudness. Through the P1A+P3A, almost all pianos seemed closer to the front of the stage but not forward or aggressive. This aspect of the P1A+P3A’s ability was a joy to experience.
Strings demonstrated the same heightened presence, with an interesting twist. Textures were somehow more revealing of individuals playing. On some Deutsche Grammophon recordings, especially the ones remastered using Original-Image Bit-Processing, the string sections of the Berlin Philharmonic under Herbert von Karajan’s direction sounded more unified than those of several other European ensembles. This prominence somehow made me became very conscious of the fact that I was listening to a high-resolution system, sonically exciting to one audiophile and perhaps distracting to another. Either way, I believe this level of resolution is something to be marveled at. In addition, the intensity of emotional resonance accorded by such resolution was undeniable.
Depending on the priorities an audiophile has and what his system is capable of, this level of resolution can work either way. I enjoy the faithful reproduction of the complexity of tonal colors. My experience with PT gear might have altered my sonic priorities somewhat. Most of us pursue certain sonic qualities when we assemble our systems. To those whose standard of excellence rests heavily on a system’s analytical prowess, this instrumental individuality resulting from excellent resolution might sound too rosy.
To me, listening to recorded music will always carry a different set of priorities from those of a live concert. For example, during a live concert, there are plenty of visual aids both on and off stage. Players may not be as sonically prominent as they are when invisible, via an excellent sound system. Live music making is the ultimate in resolution.
Telarc CDs sounded very different. At 24/192 upsampling, the first thing I noticed was air. The impression of high resolution did not impose itself onto the original signal as prominently as it did with CDs from other labels. However, I could discern hall ambiance in the recordings to a greater extent when compared with both the pre-upsampled signal and with the CDs from Deutsche Grammophon. The trademark bass drum still possessed that gutsy punch. All aforementioned aspects of improvement from other labels happened to Telarcs as well, though in a less dramatic degree. The strings, however, did not go through the transformation I noticed with those other labels. Nevertheless, given a generally high recording quality, Telarc’s orchestras still produced some of the best sounding fiddling available.
Overall, most labels’ upsampled CDs still sounded relatively thinner in body than those from Telarc.
The P1A and P3A are worth auditioning whether separately or as a combo.
The P1A+P3A combo helped alleviate the limitations of certain recordings by maximizing the available resolution, but it does not alter fundamental flaws. In addition, careful system matching remains the most important factor in getting the sound that you want, regardless what you expect PT gear to do for your system. Do not underestimate this importance.
In upsampling, an explanation of the reason one CD will benefit more than another remains to be offered. However, the question becomes momentarily less intriguing when we consider the possibility that some labels’ recording technology is be so advanced that the upsampled signal might look almost identical to the original. If that is the case, then the same situation may also be applied in the context of the Wadia 27 and P1A+P3A. Because I lived with the Wadia 27 for four years, my P1A+P3A findings are perhaps less dramatic than they might have been.
Audiophiles are lucky in that they only have to spend a fraction of what it took just a few years back to attain state-of-the-art performance in CD playback. Except for the ultimate designs, the P1A+P3A in its current state will easily outperform most digital front ends and will be even more formidable when PT comes out with a transport designed to be linked to the P1A.
Last but not least, depending on an audiophile’s components, it is safe to assume that he or she will be pleasantly surprised by the lateral and layered soundstaging abilities of the P1A+P3A, as an excellent demonstration of what today’s digital audio technology can do. At this asking price, I am astounded.
In my opinion, the P1A+P3A rivals the best high-end gear in terms of microdynamics.
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