Perpetual Technologies P-1A Digital Correction Engine and P-3A Digital-to-Analog Converter
by Tom Lyle
Four months have passed since Doug Blackburns review of the Perpetual Technologies P-1A/P-3A correction engine/DAC combination. I received samples of these components at about the same time as Doug. Because of my experience in recording studios, which includes CD mastering, as well as my LP-devotee skepticism that CD playback could never sound acceptable at a reasonable price, I thought it would be interesting to tell about my experiences with the two Perpetual Technologies components.
Except when played on very expensive players through correspondingly expensive associated gear, CDs still sound like CDs. That is, digital sounds comparatively artificial and not at all as involving as even the most modest high-end analog systems. It is obvious that CDs have significant advantages over LPs in terms of background-noise rejection and convenience. In spite of these, rendering an inexplicable sense of involvement is the vinyl discs strong suit. Its superiority on much material is also due to its more organic sound and the increase in air around instruments, voices, and other sounds on most material.
It is a regular practice in the studio to record at a higher sampling frequency and with higher resolution, then mix that signal down to the standard 44.1Hz sampling rate with 16-bit resolution. On paper, the higher sampling rate and resolution should not improve the sound, but in practice they do. Some cynics will regard upsampling as analogous to attempting to turn lead into gold, but from experience, I believe it should improve sound quality.
And it works with the Perpetual Technologies units. The P-1A converts the signal from 44.1Hz and 16 bits to 96kHz and 24 bits, then passes it along to the P-3A to convert the digital signal to analog. How much better than "normal" CD playback does it sound? Significantly so, and I suggest reading Doug Blackburn's review if you want a complete description. The P-1A/P-3As performance is one that comes very close to the sound of the pricey units Ive heard -- ones Id be afraid to purchase because of the ever-changing technology.
I think the transparency that the P-1A/P-3A combo injected into the system made all CDs truer to their original source, so if a CD was mixed and/or mastered with any frequencies boosted, lowered, or any other anomalies, these flaws were made very obvious. Any loss of dynamics, transparency, and flatness of frequency response come not from the workings of the Perpetual Technologies products, but from the creation of the CD itself. This was made clear to me when playing CDs mastered in a near state-of-the-art recording studios with yours truly in attendance. As the saying goes, "Garbage in, garbage out." Thankfully, the converse is also true. The best-sounding CDs in my collection showed how good the Perpetual Technologies combo was.
I used the Perpetual Technologies units with the allied Monolithic Sound P3 Perpetual Power Plant power supply, which increased the units performance further. And when driven by a decent transport, such as the affordable and user-friendly Pioneer DV-525 DVD player, and with a good digital cable, their performance was enhanced even further. In a nutshell, the Perpetual Technologies P-1A/P-3A/Monolithic Sound P3 combination is as good as some units costing thousands of dollars more. Is it as good as my LP playback system? Thats difficult to say. I dont think its a question of better or worse; theyre just different. Both have their advantages. Essentially, the Perpetual Technologies units represent the pinnacle of what the 44.1/16 format is cable of within a reasonable price.
Trouble in paradise?
A couple of operational issues. Since I obtained units that were manufactured relatively early in the production run, I assume that at least one of these has been dealt with. The others Im not as sure about, but none of them would prevent me from recommending these units to any audiophile who wants to get the most out of his or her CD collection.
One problem was a static-like sound that was produced from the P-1A with certain CDs. Jon Lane, the technical director at Perpetual Technologies, told me that an undocumented minor flaw in the input receiver caused this. The solution was merely a software revision, and the offending chip will be totally replaced in further production when the P-1A is upgraded to 192kHz (!) status. The company is offering to repair any faulty units free of charge that were manufactured in this way. Jon also said this flaw was made more obvious on CDs mastered at an abnormally high volume, such as Santanas Supernatural [Sony 49494].
More troubling, though, is when the P-1A is not fed any signal due to no power to the CD transport or when there is no disc present for too long a time. The P-1A goes into standby mode. When you start playing a disc, the unit automatically becomes active -- the P-1As input LED turns from red to green and the unit processes the signal and passes it on to the DAC. But this does not happen instantaneously, nor does it occur silently. A rather loud "click" comes through the speakers, and if the program material begins too soon, the first millisecond is muted. It is also partially obscured by the noise. This was not too bothersome; I just had to start a few CDs a second time if I wanted to hear the unaffected first sound of the program.
The optional Monolithic Sound power supplys benefits to the sound quality are unquestionable. My only complaint was that the cables that link the power supply to the two Perpetual Technologies units are awfully short, about 18". I have to place the power supply on its side to reach the two units on the second shelf of my equipment rack. Even though the P3 has some shielding, Im hesitant to place the power supply anywhere but on the floor next to the rack for fear of any induced electromagnetic hum being generated if placed anywhere near the units for which it is supplying power. Monolithic Sound told me that they purposely designed the cords to be short because longer cords would be detrimental to the sound quality. The minor inconvenience of shorter cables is certainly worth it.
Lead turned to gold!
Not too much to complain about and much to admire from the Perpetual Technologies P-1A and P-3A. And with Perpetual Technologies software upgrades on the horizon, these are perhaps the last CD playback units we will have to purchase.
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