Silver Circle Audio PP1 5.0 Power Conditioner Raising the ante by lowering the floor. Review By Rick Jensen

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September 2007

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Silver Circle Audio PP1 5.0 Power Conditioner
Raising the ante by lowering the floor.
Review By Rick Jensen

I will start with the conclusion because it shouldn't wait. The Silver Circle Audio pure power one 5.0 is a watershed product. There is life before you use the 5.0 and life after it. After is better.

The pure power one 5.0 (PP1 from here on in) is a new product from Silver Circle Audio, which is based in Houston. Silver Circle has been making a range of interconnect and speaker cables, as well as power cords, since 2002. Also in the product line are the "predecessors" of the PP1 5.0, the pure power one and the pure power one 3.0.

Is This An Amplifier?
The PP1 is a large and heavy component. It measures 19" x 8.5" x 14" and weighs approximately 110 lbs. It takes two fairly strong people to move it around, unless you are the sort who buys his skin cream from Balco. At first view, you would not think you were looking at a power conditioner of any type. It is unlike every other power conditioner that I have seen (and I have not seen them all, not by a long shot) in that, in spite of its size, it looks very good. The overall appearance resembles that of a large solid-state power amplifier, and one that is handsome to boot. The sides of the unit that I reviewed are made of Bubinga, or African rosewood; cherry, ash, and jatoba are also available. The brushed front panel is finely done and elegant in its lettering and simplicity, and the little blue light that indicates power on has a little of that pretty Hovland glow.

There is just one button on the front panel, an on-off. The rear panel is a little busier, as you might imagine, but still very simple. There are eight places to plug in your gear – four twin Furutech Gold 20-amp receptacles. I was interested to see that, in contrast to my old Tice unit and to a few Monster power conditioners I have or have had, there are no demarcations such as "analog" or "digital" or "power amplifier" among the receptacles. I have always been just a little suspicious of those groupings, as though isolating the digital plugs an inch away from the analog was going to markedly clean things up. Given that there are those who would radically isolate the power source for everything digital from everything analog, merely to pair receptacles in a given conditioner has seemed to me to be underwhelming. Equally, it just seems better to design the unit so that any voltage is effectively clean and isolated from any other. In any case, one can always plug the digital units on the left and the analog on the right, and just keep the sources a bit discrete.

Silver Circle Audio PP1 5.0 Power Conditioner On the rear panel is also the inlet for the power cord, made as well by Furutech, and fuses. It is worth noting that the PP1 comes with Silver Circle's premium Vesuvius power cord. The cord, which appears to be very substantially built without being inflexible, is at the top of Silver Circle's range. It retails for $900 on its own for a 6-ft. length.

Other than that, all the design is on the inside of the unit. Responsible for most of the weight of the PP1, as well as the extraordinary performance of the unit, is the proprietary 5.0 kVa isolation transformer that, according to Dave Stanard, the president of Silver Circle Audio, itself weighs over 75 lbs. I didn't remove it to find out, but it is damned heavy.

You Mean It Sounds Like Nothing?
A very engaging and warm guy, Dave Stanard likes to emphasize that he is no brilliant audio designer. (He might like to be called brilliant, but not as an audio engineer; happily, he has worked with engineers specializing in power transmission to arrive at this design). Stanard says that he simply has assembled a group of very high-quality parts, some of which are stock and some of which are proprietary, based on their contribution to the elimination of noise. The PP1 evolved by trial and error, without a dogma guiding the design.

My first question in regard to the PP1 was as to why it costs what it does. After all, as I tell my friends, it's a very big power strip, right? Stanard points out that the parts cost is very high: the receptacles retail for $400, the IEC plug for $100, and the aforementioned cord is not cheap. Wholesale cost is much less of course, but the total parts cost, claims Standard, is a higher percentage than one will find on other high-end audio products of any sort. While I cannot vouch for the numbers, I can say that the result is spectacular, and so perhaps the money has been well spent.

In addition to the ingredients mentioned above, there are other elements that attest to the care with which the PP1 is assembled. All the wiring is 10-gauge silver-plated copper, all the contacts are Caig-Deox It Gold-treated, and the face plate is a 3/8-inch solid block of anodized aluminum. Silver-plated copper was used because Stanard, who started out by designing speaker cables, found that the silver was faster but the copper, while mellower, did very well with the bass. As a result, all of Silver Circle's speaker cables use a combination of the two metals, as does the PP1.

The goal of the design was pretty straightforward: get rid of noise in the line. Stanard says that of the three types of noise (common-mode noise, as from motors – think of a hair dryer), differential mode noise, and DC noise in the AC line, the PP1 attempts to eliminate the first two. (He may add to the PP1 to address the DC in the future). While this may seem simple, it is not always easy. My own house has been very problematic in terms of line noise. I have used many different power treatments (although no power regenerators) without a lot of success. The line may be relatively quiet for hours and then worsen later on. Indeed, there was one time a few years ago that I was unable to review a superb power amp because it didn't like my line enough to work in my listening room. (It worked beautifully elsewhere in the house but unfortunately that was not where the appropriate components resided.) I ran a dedicated line into the listening room but confess that I did not have the dedicated line come in directly from the street. Consequently, although the line is better than it was, it is still noisy as it runs through the circuit panel for the house. Yes, I know I need to replace it, but maybe we'll sell the house first...

Thus, the PP1 had its work cut out for it.

Happily, it did not take very long to see if the PP1 was up to the task. I plugged my components into the PP1 and then checked to see if it was on. It was, but there was no noise. With the volume set at normal listening level I had to go up to the speakers and put my ear to the tweeter in order to hear a small hiss that I assume comes from the tubes in the signal path (conrad-johnson Premier 17LS and 15, Music Reference power amp). Nothing else. To say the very least, I was startled to hear the silence, and brimming with optimism.

But How About The Music?
That optimism was rewarded once the music started. First on the turntable was Alison Krauss "Let Me Touch You For a While" from New Favorite (Diverse 001LP). It would be a cliché to say that it was as if I were hearing it for the first time, but that was precisely the impression from the first few notes. It never let up. As the PP1 does not of course have a sound of its own, I will not pretend to say that it "sounds" like this or that. Rather, it clears the air completely so that whatever is on the signal source can get through as well as your system will permit. Consequently, clarity, a sense of air and freedom, and an ease of presentation of the entire soundstage all invited more and more listening.

Similarly, what one might hear by inserting the PP1 into the system will depend on the components. Without going into excessive detail, for me, the bass was more full and better defined, the mids were liquid and defined, and the highs were more extended, more detailed and utterly non-fatiguing. Female vocals gained intimacy and male vocals had less chestiness in the lower registers. Patricia Barber's piano on Café Blue sounded more like the instrument in my living room (albeit played a tad better) – resonant, filling the room without overloading the eardrums.

The width and depth of the soundstage did not 'change' but the apparent volume of that stage increased – within the bounds of the soundstage there just seemed to be more room for all of the instruments. Interestingly, that impression of greater volume, more elbow room, held for jazz bands ("For Duke") playing in real space as well as for amplified music that did not reflect a real space. I put "Uptown" by Prince from Dirty Mind (WB BSK 3478) on the Linn. I have played the song at least two hundred times. With the system plugged into the PP1 there was so much more room, so much less crowding of the various synth lines that I had to turn the volume up. At that point, it became quite clear to me that I was turning the volume up significantly higher on every record, playing the music louder, and yet making less noise. All this from a big power strip.

One consistent impression on all unamplified cuts was that of more precise localization of the instruments. Whether classical, as with "Land of Hope and Glory" from Elgar's Coronation Ode (EMI ASD 3345), or jazz -- Art Pepper Meets the Rhythm Section (Analogue reissue APJ 010), it was easy to 'see' where the music came from. I do not believe that the localization changed at all but rather that I perceived it as such because there was less noise masking the musical information. As though the windows were all cleaned.

It would not be an overstatement to say that whatever is good in your system is likely to be better with the PP1 up front. At the same time, it is also accurate to state that the bad stuff will come through better, too. In my case, I was able to hear more clearly some midbass wobbliness from the turntable (it didn't show up on CDs), as well as excessive coolness on most standard CDs. Neither of those flaws in my system could compete with the overwhelming improvements on so many other fronts. For better or worse, you will find out what is in those boxes but it seems quite clear that most good systems will be able to sound much better.

Should I Get One?
Making the case that the PP1 – or any power conditioner – will bring as much satisfaction and joy as a sexier toy like a new amplifier or new speakers is not easy. All it does is give you nice clean power. In my case, though, the improvement in the system wrought by the PP1 exceeds that of every component I have used in the last 25 years, with only the insertion of the Grand Prix Audio Monaco equipment stands being a close second. And it is worth noting that the GPA stands did much of the same – they allowed everything else to sound better by quieting things down. For me, the PP1 has raised the ante by lowering the noise floor. I continue to be nothing less than astonished by what I can now hear. As stated at the outset, this is a watershed product. Anyone who suspects that his power is not perfectly clean would do well to sample the PP1, with the caveat that you might not want to unplug it.