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PERPETUAL TECHNOLOGIES
P1A Digital Correction Engine/Upsampler and P3A Digital to
Analog Converter
by Constantine Soo
May 7, 2001
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P1A
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P3A
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P1A Specifications:
Interpolation Engine: Converts 16 bits Redbook CD data to a user-selectable 18, 20, or 24 bit of
resolution
Upsampling: Converts input sampling rate to a user-selectable 44.1, 48, or 96 kHz resolution level
(with future upgrade support for 192 kHz)
Jitter Reduction: Re-clocks bitstream to 2 peco-seconds of total jitter via a phase-locked loop
Interface: USB
DSP: Analog Devices SHARC 21065L 32 bit floating-point platform
Digital inputs: S/PDIF (via RCA), AES/EBU, I2S.
Power: Auto swtiching DC power supply compatible with all wall voltage formats
Weight: 6 lbs (shipping)
P3A Specifications:
DAC: Crystal Semiconductors CS4397 reference quality 24 bit 44.1/48/96/192 kHz stereo D/A
conversion system platform
Dynamic range: 120 dB
Signal to noise ratio: 140 dB
Input receiver/Sample rate converter: Crystal Semiconductor CS8420 (accepts 16 to 24 bits, and
sampling rates from 32 to 96 kHz)
Upsampling: Auto-upsampling inputs - converts ALL standard CD’s to 96 kHz
Jitter reduction: Built-in
Digital inputs: S/PDIF coaxial, toslink, AES / EBU, and I2S – all galvanically isolated via transformer
coupling
Power Supply: Class A high-current audio output stage with 5 pole split passive/active anti-
aliasing filter surrounding high-performance Burr-Brown OPA134 driving the outputs
Phase inversion: Digital (user selectable)
Website: http://www.av123.com
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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.
BACKGROUND
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!
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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.
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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.
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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
(jlane@perpetualtechnologies.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.
PA1 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:
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"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."
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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.
LISTENING
"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.
AFTERTHOUGHTS
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.
Associated Equipment:
Digital Front End
CEC TL1
Sony SCD-777ES SACD player
Wadia 27 Decoding Computer
Amplification
Krell KRC-2
Monarchy Audio SM-70
Music Reference RM9 II
Loudspeakers
Celestion SL700
Klipschorns (1993)
Cabling
Audio Alchemy DST Digital Transceiver in XLR (1m)
Cardas 5c (8ft)
Granite Audio #470
Perpetual Technologies I2S between P1A and P3A
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