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Published February 1, 2001

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Perpetual Technologies P-3A Digital-to-Analog Converter and Monolithic Sound P3 Perpetual Power Plant Power Supply

For a certain type of audiophile, systems are like sharks -- if they're not in the process of constantly moving forward, they die. Or at least their owner's interest in them dies. Other folks, more normal ones I suspect, don't require that never-ceasing shock of the new to stay involved. Once their systems sound good, they could listen happily forever.

Well, maybe not forever, but at least until something basic in the technology changes. My friend Ruben is like that. Other than a speaker upgrade to his ProAcs, a few changes in cabling and a Shakti stone or two, his system hasn't really changed since I started reviewing ten years or so ago.

As I constantly change components for review deadline after review deadline (not a complaint, just a description!), I sometimes envy Ruben listening contentedly to his oh-so-musical system. Othertimes, I can't wait to call him and tell him how good I have it listening to a new barrier-shattering piece of kit. Even more rarely, I get to call him and torture him with the news that I have found something amazing and, oh, by the way, it costs a lot less than that new lute he's been fantasizing about. With the Perpetual Technologies P-3A, I've been fighting my urge to make that call -- I thought I'd tell you about it first.

Faster Than A Speeding Bullet . . .

The Perpetual Technologies P-3A is miniscule. It's 5.5 inches by 8.25 inches by 1.75 inches and it can be placed on its broad side or arranged as a thin vertical tower -- for the latter arrangement, it comes with stick-on disc-shaped feet. The P-3A's faceplate describes an arc with a rounded groove running from one end to nearly the other. The firm's logo is inset into a circular depression just below the groove. At each end of the groove is a large, rounded control button; between them are seven inset three-color LEDs that indicate phase, sampling rate and active input. The rear panel has a pair of RCA outputs and a 9V power connection. Signal inputs include optical (TosLink), AES/EBU, coaxial RCA and I²S five-pin mini-DIN (Audio Alchemy standard).

The unit comes with its own separate wall-wart 9V power supply. Monolithic Sound manufactures a replacement unit with substantially better filtration and bridge rectification (more on this later).

The P-3A does not, strictly speaking, interpolate 16-bit to 24-bit data. It dithers the signal, so the converter outputs slightly enhanced (approximately equivalent to 17-bit) data in a 24-bit datastream. What upsamplers can do, however, is, ummm, upsample, since that's just a matter of multiplication; so it will upsample 44.1kHz to 96kHz, if you so choose.

To actually convert 16-bit to 24-bit data requires digital signal processing, and Perpetual Technologies manufactures a unit (the P-1A) which does that. My P-1A sample did not seem to be operating correctly, so I'll comment on it in a later review.

A Crystal Semiconductor CS8420 input-receiver sample rate converter chip (also used in the Bel Canto DAC1) receives the incoming signal. It accepts anything from 16- to 24-bits and any sample rate from 32kHz to 96kHz. It's always set to feed 96kHz to the DAC chip. Jitter reduction is based on a high-precision, low jitter, quartz oscillator, which generates a stable reference frequency clock for all conversion functions.

The P-3A uses a Crystal CS4397 192kHz 24-bit DAC chip, which is a cutting-edge 24-bit 44.1/48/96/192 kHz stereo DAC (192kHz is not currently available on the P-3A but will be when there are consumer applications available). The CS4397 employs a high-level digital interpolation filter that feeds an oversampling delta-sigma modulator which, in turn, drives the dynamic-element-matching (DEM) selection block. That block routes the signal to a multi-element switched capacitor low-pass filter for low-clock jitter sensitivity and then out.

The analog output stage is constructed around Burr-Brown's OPA134 op-amp and runs in class-A.

More powerful than a locomotive . . .

Fancy as it is on the inside, the sparse control array of the P-3A is reflected in its ease of use (emphatically not true of the P-1A, but that's another story). Since everything is upsampled to 96kHz, all you really need to do is choose an input (the unit does not automatically sense an incoming signal). The appropriate LED will indicate the received sampling rate by its color: red for 44.1kHz, green for 96kHz, no light for 192kHz. The program button controls absolute phase.

The sound? In a word, spectacular! To obtain this much processing power for $699 was a pipedream just a few years ago. Now we can routinely buy it for under a $1000. But even though there's a lot of choice when it comes to upsampling converters, the Perpetual P-3A stands out in the crowd.

Where to start? Judy Garland's Recorded Live and Complete at Carnegie Hall [DCC-1135/2] had a huge soundstage with tons of low-level detail and high frequency shimmer. It's a fantastic sounding disc, but switching from the Musical Fidelity A3CD alone to the P-3A was like entering hyperdrive. It slammed home so much more bottom end solidity that I glanced around my living room for an exit light. And space -- lord, was there ever space. I almost thought I could see the old Carnegie ceiling cut-out up above me.

Dynamics were amazing. I listened to an old favorite, Rendezvous by the Jerome Harris Quintet [Stereophile STPH 1013-2], which, like the Judy Garland, is recorded at a lower level in order to accommodate its unusually wide dynamic range.

Harris' bass was woody, solid and incredibly full-bodied. He's a tone monster and his sound on this album is so rich and earthy, I can never get enough of his Taylor Acoustic bass guitar. But it was Marty Erhlich's alto sax and Artie Barron's trombone that cut through the acoustic like straight-edged razors through silk. Man! You could blow out a candle with the amount of air those two can move -- and that's in a solo passage.

Having been impressed with the sound of the straight P-3A, it seemed time to try Monolothic Sounds' P3 Perpetual Power Plant (three "p"s, get it?) power supply. The P3 is a solid brick of a unit designed to power one P-3A and one P-1A (they take different input voltages). The MSP3 features separate high-current 2.5A low-output impedance transformers for each Perpetual unit. A discrete, full-wave bridge rectifier with four discrete diodes, said to be "ultra-fast," supplies 10,000µF of filter capacitance, bypassed by an exotic Siemens metal-film cap.

And it works like a charm! Name your parameter and the P3 improves it. Bass response is better, fuller, deeper-bodied. High frequencies are smoother, more extended, with extended decay -- string overtones are scary-real. And the noise floor, already subjectively outstanding, seems to drop even further -- you can hear a flea fart in a cathedral with the P3 driving the P-3A.

The Monolithic Sounds P3 is not an accessory for the P-3A -- it should be considered mandatory.

Able to leap tall buildings in a single bound . . .

At $1048, the P-3A/MSP3 is pretty directly competitive with the Bel Canto DAC1 at $1295. What differences are there? The Perpetual sports an I²S input, which is a really fine digital interface, although one that is simply not used very much, so it might not factor into your calculations.

More importantly, the P-3A has an outboard power supply, whereas the Bel Canto runs fragile low-level signals right by its PS, with a resultant low-level hum that is visible on published measurements of the unit -- and which is undoubtedly responsible for a certain amount of opacity in its soundstaging. The Perpetual Technologies P-3A rings its bell when it comes to reproducing small sonic details way down in the mix -- which means it creates a much better simulacrum of the acoustic space by reproducing the most minute dynamic differences.

Listening to Robert Silverman's Beethoven sonata box [Orpheum Masters KSP 830], I compared the two processors. The Bel Canto had a smooth tonal quality that many listeners will find seductive. I certainly did. But extended comparisons to the P-3A have made me question whether or not that's a good thing. The P-3A has a presentation that seems sharp at first, especially compared to the Bel Canto, but the more I tried to assign a cause to the Perpetual's "aggressive" attack, the more I thought it was about right and the DAC1 was veiling the leading edges of transients. Finally, the nickel dropped and I realized what the Perpetual's sound reminded me of.

It was like moving down directly in front of a musician after listening to him further back in the hall. The "sharpness" is actually, I now believe, the sheer abundance of detail that makes it sound over the top at first, just as standing in front of an acoustic guitar "sharpens" the sound in real space -- what you're hearing with the P-3A is just closer to the real thing than you've ever been before. It can be startling.

Is it perfect? No. I suspect that at least some of that startling "closeness" might actually be a slight overemphasis of the upper midrange, but I can't be sure. It reminds me, more than anything, of the sound of a Mark Levinson No. 360S D/A converter, which I also found a tad "aggressive" at first.

Fighting the Never-Ending Battle for Truth . . .

Wait! What am I saying? The No. 360S is a seven thousand dollar processor! Can I possibly be comparing it to the sound of a $1000 combo? Well, yes, keeping in mind that the P-3A is a much more limited unit (it's not balanced for one thing) -- the real point is that the current state of technology is such that affordable DACs now routinely offer sound that only the most exotic separates used to manage.

The P-3A is well-built and well-thought-out. It sounds so much like the best digital converters you can buy that it's scary -- either Perpetual Technologies has severely underestimated its price, or a thousand bucks buys you more digital processing power than ever before. I vote for the latter explanation.

I also enthusiastically recommend the Perpetual P-3A as one of the best buys in audio. Actually, it's not just a best buy, it's super.

...Wes Phillips
wes@onhifi.com

Perpetual Technologies P-3A Digital-to-Analog Converter
Price: $699 USD
Warranty: One year parts and labor

Perpetual Technologies
368 South McCaslin Blvd., Suite 189
Louisville, CO 80027
Phone: (303) 543-7500
Fax: (303) 543-7200

E-mail: sales@perpetualtechnologies.com
Website: www.perpetualtechnologies.com

Monolithic Sound P3 Perpetual Power Plant Power Supply
Price: $349 USD
Warranty: One year parts and labor

Monolithic Sound
515 Sandydale Road
Nipomo, CA 93444
Phone: (805) 929-3251

E-mail: info@monolithicsound.com
Website: www.monolithicsound.com

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