World Premiere
Silver Circle Audio pure power one 5.0
A great unit gets upgraded!
Review By Rick Jensen
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  I am increasingly convinced that noise, artificial noise of all sorts, is among the principal elements that prevent the reproduced sound experience in the home from sounding like something live. It's almost too easy, albeit probably true, merely to invoke the maxim that nothing can and will sound like live music in a real space. I guess I agree with that; there is nothing that seems to indicate that it is not so.

Within that familiar statement are a host of factors that are potentially responsible --the size of a real concert space, the period and propagation of sound waves as well as the physical nature of their sources, the lack of mistakes by performers and coughs from the audience. We can all come up with our lists.

But the spurious sounds, however subtle, that make their way into the reproduction of a recording, seem to me to be of a different nature. They impose themselves on the musical performance in a ‘global' way – i. e. across the spectrum of the music that we hear. Depending on the source, they may be inherently or largely amusical – hums, white noise, intermittent distortions, shadows or reflections of other signals in the chain, and more. There may be noises and distractions in the concert hall. One hears horns, police sirens, traffic, ventilation systems, and the rustling of papers. These things may also be "amusical". But an important difference is that they are transitory, and do not normally become part of the musical performance; they don't accompany you throughout the evening. I believe what I am indicating is that that is a big advantage in favor of the concert hall.

All of which brings me (again) to the subject of this review update – the Silver Circle pure power one 5.0 power conditioner. Or as I am fond of telling any non-audiophile who sees it, a really big, heavy, expensive power strip. If you are reading this, of course, you know it is much more.

Situation
I will recap only briefly the conditions prior to my review of the original version. I had had some serious noise problems in my system (really, in my house) several years ago. It became enough of a problem that I first ceased to use my system for a few months while I was unable to fix it. I had a separate and dedicated line to the stereo room from our electrical panel installed, along with high-grade receptacles for the room. Yes, we could have tried to have the line go back to the utility line in the street, but that would have required permits from the town fathers, which are not easily forthcoming.

I did try a number of other filters and conditioners from some well-respected manufacturers, but couldn't fix the problem completely. Then I heard (really, I saw) the Silver Circle pure power one 5.0 (PP1 from here on in) at a show in 2007 where I met Dave Stanard, the head of Silver Circle .The system in which it was playing sounded sensational. I inquired about the PP1, and thought it might have something to do with the fine sound. Dave sent me a unit for review, and my noise problems were solved. I won't repeat here all the details about the design of the unit, about the goals, or about the construction. You can refer to my original review of the Silver Circle Audio pure power one 5.0.To be brief, the PP1 is pretty massive for anything that is not an amplifier. It looks about the size of a large amplifier and weighs 110 lbs.It is not easy to carry around the house, but presumably that would not be your goal in owning one.And, as I mentioned earlier, it comes with the high-end Vesuvius power cord made by Silver Circle (of which there is a new model – see below), which is beautifully built and happily, somewhat more flexible than tempered steel.

Evolution
So, why the update? What has changed? Just two things – the filter and the cord.However, the major change involves the filter. As I listened to the new unit with an updated version of the original power cord, but not with the optional Vesuvius dcβ, my comments will need to be taken in that light. Accord to Dave Stanard, the original filter was a hand made version of a very common circuit used to filter out common mode and differential mode noise.  After living a long time with his original creation and extended listening, Stanard figured they could do better and began experimenting with various filters. As noted in my original review, Silver Circle products are not the reflection of a specific design methodology, other than trial and error through both measurement and lots of listening.

Based on the recommendations of various engineers and audio designers, Silver Circle arrived at using a filter that is a combination of resistive and capacitive elements. They are not ready to publish the schematic, but the new filter far outperformed the old with respect to the job it had to do. Per Silver Circle , the huge isolation transformer removes about 99.99% of the common mode noise found in the line. The filter removes the rest of the common noise as well as the differential mode noise, and the new filter just did a noticeably better job.

With regard to the new Vesuvius power cord, as I did not audition it, I will just repeat what Silver Circle describes. They found that when DC is present on an AC line in excess of 1 volt, it makes a torroidal hum. They designed a Vesuvius power cord (the Vesuvius dcβ - $950 separately) that removes the DC with an inline diode/capacitor circuit. Stanard notes on his website "what is even more interesting is that in listening tests, we found that the inclusion of this circuit actually increased dynamic "slam" and detail in the music. I believe it's a result of the theory of unintended consequences, or the travels of the Three Princes of Serendip. This is not what we were looking for, but we'll take it. Reducing DC and increasing dynamics."

So, how did it sound, or not sound, as the case may be? I would probably not be writing this if it were not worth the effort.

First, the whole system is quieter than ever, which, after all, has to be the main objective. I have to get right up next to the speakers to hear any kind of noise, and that with the volume turned up a level that most would consider quite loud. That aside, there is just an overall sense of quiet. With digital sources it's actually a little eerie. I realize now that I have always known when the system is on (of course, the glow from the tubes gives it away) by ear – so when the music starts it's a surprise but not a shock. With the new PP1, it comes out of nowhere and gives me a start most of the time.

Audition
In fact, with the Empire Brass Quintet's first cut ("Hopper Dance") on the McLaren Test Tracks CD (available used from Amazon), I jumped every time. This test CD has some very well-recorded tracks and some of them, like this percussive piece, are very enjoyable as well – not always the case on demo discs. What also struck me here is that the brass had the attack that one would look for but not the aggressive leading edge, that kind of bleat, that one often hears with recorded music. There was a certain softness to the horn tones that reminded me of live music, where brass sections can be exciting without frying your eardrums. The drums – the other stars of this cut, are deep and round with great depth and definition. And the dynamics are all one could wish for; I have played this recording for friends, all of whom have wanted to get their own copy immediately afterward.

As a contrasting piece on the same disc, there is a Sara K recording of "Brick House". While it isn't my favorite music, it is well-recorded with good ambience. Her voice is intimate and a little smoky and lacks no detail. The string bass at the beginning, like the earlier cut, has great detail even while being soft, like a real (not recorded) bass.

"Home" from New York Reunion by the McCoy Tyner Quartet [Chesky SACD 206] is one of my favorite cuts, and one I listen to with every piece of equipment for a sense of continuity and comparison. Until hearing this via the new PP1, I had not noticed the extent to which the Ron Carter – Tyner interplay is what drives this song. It's a great melody, but I got the impression that if the song is "about" something, it may well be changes in rhythm (come up with whatever metaphor you want to fit the title as well). My listening notes said "no haze at all" – maybe that allowed me to hear through it better.

The same sense of naturalness pervaded the Mozart Clarinet Concerto from Antony Michaelson / Michaelangelo Chamber Orchestra [MFSACD017].This is a very well recorded and nicely played SACD. The spaces both linear (between the notes) and spatial (soundstage) gave the feel of live music – it was just stress-free. Given that my listening room is a small one, there is always a danger that the smaller space will render certain instruments or certain passages too aggressive compared to live. 
In that context, "stress-free" is a good thing. As above, I believe that the delicacy, richness and natural dynamics that I kept noticing were a result of the absence of non-musical signals.

Conclusion / Reflection
Having had the good fortune to hear a lot of very fine audio equipment over the years, I have had many occasions where I have been surprised by something good that I had never heard before. Most of us have had these "aha" moments. In the earlier review, I noted that only the Grand Prix Audio Monaco equipment stand shocked me anywhere near as did the PP1.One other component that dropped my jaw in the same fashion was my original Linn turntable, almost thirty years ago. I was given one of those demonstrations where the arm, cartridge and cabling were all identical, but the turntable was different (in this case, it was the old CJ Walker). The Linn trounced the Walker , and I had no idea why or how. One reacts in much the same way to the PP1 or the Monaco .A line conditioner? An equipment stand? They don't even make music.

While my experience may not parallel that of others, I might hazard a guess at why these three stand out. All three are more or less passive components. They are not passing the signal. All they really have to do is to get out of the way and/or to help other components to get out of the way. By being silent, whether via attenuation of vibration (GP Audio and Linn) or cleaning up the power line ( Silver Circle ), they strip away the haze and the garbage that can affect every part of the music, every bit of the reproduced recording. Perhaps it is not such a surprise that the improvements in the listening experience from components such as these can be dramatic, because their impact is potentially so broad. I don't know for sure; as I said, this is a guess.

Regardless of why the PP1 manages to make everything else sound so good, what remains is that it does. There are likely other power conditioners out there that do a similarly great job. I have not had the chance to hear them all, and certainly not under ‘controlled' conditions. But the PP1 merits the serious consideration of anyone who has an investment in a music system – hardware and software – and anyone who is invested in music. It remains a great and essential component and while the price remains at $5000, existing owners can have their units upgraded by Silver Circle by paying the shipping costs to and from the factory.

Specifications
Type: Power filtration and distribution unit
5.0 kVa Proprietary 75 pound isolation transformer
Massive black anodized aluminum chassis
Furutech Gold-Plated IEC inlet
10 AWG silver-plated copper power path wiring
Proprietary hand-built EMI/RF filter
Custom hand-built "soft-start" circuit with 30-amp rated relay
50-amp rated terminal block
Standard with Vesuvius Power Cord
5.0 - 4 Furutech Gold 20-amp receptacles.
All contacts treated Caig DeoxIT Gold
Extensive internal vibration dampening
Dimensions: 19 x 8.5 x14 (WxHxD in inches)
Weight: 110 lbs.
Price: $5000

Company Information
Silver Circle Audio
3507 Shadow Bluff Court
Houston, TX 77082

Voice: (281) 870-8272
E-mail: davestanard@silvercircleaudio.com
Website: www.silvercircleaudio.com