PS Audio Power Plant Premier AC Regenerator Page 2

One of the most impressive things about the Premier is its ability to reduce harmonic distortion in the incoming AC. At various consumer-electronics shows, PS Audio had earlier demonstrated this effect of the Power Plant design by using a Fluke power-quality analyzer. With the Premier, they've included a built-in harmonic-distortion meter; you can switch the front-panel display to show the THD of the incoming AC and of the output. In my situation, the input THD was in the region of 3–4%, the output around 0.3%.

The Premier allows a choice between sinewave and MultiWave. However, it's missing some options available in earlier Power Plant models: variable-frequency sinewave and a variety of MultiWave settings. I guess PS Audio got tired of people calling customer service and asking, "Is MultiWave 1 better than MultiWave 2, or should I set it at AutoWave?" The MultiWave pattern included in the Premier is equivalent to what was called TubeWave in the last generation of Power Plants. However, not all audio electronics respond well to MultiWave, which shouldn't be used with anything that has an AC motor, and not if, as the Premier's owner's manual puts it, you hear "funny noises" coming from the equipment. For consistency in reviewing digital source components, preamplifiers, and power amplifiers, I've settled on using the sinewave setting, which is the same as normal AC except cleaner, and avoids the possibility of any negative interaction of MultiWave with audio equipment's power supplies.

The Premier has five pairs of isolated AC outlets, all functionally identical, and distributed among three switchable Zones. Again in contrast to some earlier Power Plant models, the Premier has no outlets with only passive filtering. Thus, although one set of outlets on the Premier is labeled Power Amp, that's just for convenience; these supply the same regenerated AC as all the other outlets. The Premier's 1500W maximum output is enough for just about all power amplifiers, so the passive outlets aren't needed. The Premier also has an ingenious way of dealing with the turn-on power surges of very large power amplifiers: If the current needed exceeds the Premier's regenerated power capabilities, the Premier connects the amplifier directly to the wall AC until the temporary need for high power has abated. For those with amplifiers whose long-term thirst for power is unquenchable (or who can't afford the Premier), PS Audio offers the Duet and Quintet Power Centers, which have filtering and surge protection, but not regenerated power.

The Premier has one more trick up its sleeve: isolation of noise generated by equipment plugged into its AC outlets, using common-mode filters made of "nanocrystalline." No, this isn't another name for Unobtainium, but for FineMet, a recently developed soft material made by Hitachi Metals that has the highest permeability of any magnetic material currently available. The result, according to PS Audio, is "an isolation and cleaning network that is both non-intrusive and an excellent performer."

On the convenience side, the Premier has a remote control (selection of display mode, sinewave/MultiWave, CleanWave, and display lighting), a power sequencer, two 12V triggers, CATV, and two telephone in/out jacks, all providing protection against high-voltage spikes. And here's what it says on the box: "Engineered in Boulder, CO. Manufactured in China."

The Sound of AC
For nearly a decade now, except for brief periods, the source components, preamplifiers, and sometimes power amplifiers and integrated amplifiers in my review system have received their AC power from a PS Audio Power Plant: first the P300, and, more recently, the P500. Each time I've compared the power supplied by a Power Plant with the AC from the wall (usually in the context of the review of a specific component), I've concluded that the sound was better when I used the Power Plant as the current source.

When I received the Premier for review, I did what I usually do with a new component: I plugged it in, made the connections to the system (plugged all the AC cords into the Premier), turned everything on, and just listened without trying to analyze or evaluate the sound in any way. I continued in this vein for several weeks, giving the Premier time to burn in. (Some postings in discussion groups on PS Audio's website suggest that burn-in is a significant issue with the Premier.) The sound was generally fine—but I wasn't wearing my reviewer's hat.

Then, with that hat firmly in place, I listened to an array of highly familiar CDs, paying attention to musically important details as well as to soundstaging and the overall flow of the music. The results were excellent: the combination of the Ayre CX-7e CD player, Convergent Audio Technology SL-1 Ultimate preamplifier, Audiopax Model 88 Mk.II power amps, and Avantgarde Uno Nano speakers (review to come) is a highly synergistic, supremely musical combination.

The next step was to determine what the system sounded like with all those components plugged directly into the AC wall receptacles. I disconnected all the AC cords from the Premier and plugged them into the wall. (Two dedicated AC lines serve my room, each terminated with hospital-grade receptacles.) And listened.

The sound was still very good—a bit more forward than with the Premier in the system, but not annoyingly so. Otherwise, the tonal balance was much the same. These are, individually and collectively, excellent components. Then, as I continued listening, it seemed that some of the finer details of the sound were a bit obscured, and the soundstage, while not obviously more shallow or narrow, was not as precisely delineated as I remembered from when the Premier was in the system. Time to listen again with the Premier as the power source.

I plugged everything into the Premier, turned on the system, and proceeded to listen again to the same recordings, beginning with the Chesky Records Jazz Sampler & Audiophile Test Compact Disc, Vol.1 (Chesky JD37). Based on what I felt had been a fairly subtle degradation of the sound when raw AC was used, I expected the difference in the other direction to be equally subtle.

I've never used the expression jaw-dropping in print or in conversation, and I'm not going to start now. My jaw remained in its usual place. But I was surprised by the magnitude of improvement produced by the Premier. The music became more subtly detailed, the soundstage wider and deeper, the overall sound more natural, less electronic. Noise, which can be a problem with the 105dB-sensitive Avantgarde Uno Nanos, was already quite low with the system plugged into the wall; with the Premier, it was even lower. There was no impairment of dynamics; if anything, if was now easier to hear the music's ebb and flow.

Using the Premier to feed my system its power simply resulted in a superior listening experience, an impression that persisted through repeated switchings back and forth between raw AC and the Premier's regenerated AC. I used the CleanWave function from time to time, and yes, the sound seemed even "cleaner" after this treatment. The ability to activate CleanWave from the remote was very useful, and increased my use of the function.

Except for the digital source, the system described above is all tube. To get a perspective on the effect of regenerated AC on solid-state equipment, I replaced the combination of CAT SL-1 Ultimate preamp and Audiopax 88 monoblocks with PS Audio's own GCC-100 integrated amp (which PSA calls a "variable gain power amp"), which I reviewed in the January 2006 Stereophile (Vol.29 No.1). The GCC-100 sounds very different from the CAT-Audiopax combo: squeaky-clean, essentially neutral in tonal quality (a bit on the cool side), with greater top and bottom extension, but losing out to the tube gear in "musicality"—the ability to make voices and instruments sound like the real thing rather than an electronic reproduction.

In my review of the GCC-100, I had remarked that it sounded so much better when plugged into one of the P500 Power Plant's regenerated-AC outlets that the latter might almost be considered a mandatory accessory. The P500 also has some passive filtered Ultimate Outlets, but the GCC-100 draws relatively little current, so I didn't have to use them. In a recent e-mail, Paul McGowan told me that 90% of P500 owners end up having to use the Ultimate rather than the regenerated-AC outlets for their power amps, and suggested that it would be instructive to compare the P500's hybrid regenerated/passive arrangement with the sound with all the components plugged into the Premier (which supplies regenerated AC to all of its receptacles).

It was instructive, demonstrating the benefits of supplying all components with regenerated AC. My system, with the GCC-100 and the Avantgarde Uno Nanos' subwoofer amplifiers plugged into the P500's Ultimate Outlets, sounded better than when plugged into the wall, but it acquired an extra degree of clarity when the Premier provided all the power. How much of that improvement was due to the purity of regenerated AC and how much to other differences between the Premier and the P500—such as the isolation of the Premier's receptacles using the nanocrystalline technology—is impossible to say, but the comparison confirmed the superiority of PS Audio's latest Power Plant design.

In the best of all possible worlds, AC supplied by wall receptacles would be a precise, unvarying 120V: a pure 60Hz sinewave with no distortion or other frequencies riding on it. Within the limit set by the circuit breaker, this flow of current would respond instantly to any demands placed on it by the electronic equipment plugged into the wall.

We do not live in such a world. Here, AC voltage varies, sometimes enough to damage equipment, and the waveform is never a pure 60Hz sinewave. All power supplies of all audio components must deal with these realities, and to varying degrees, they do a reasonably good job of it. The vast majority of consumers are perfectly happy plugging their audio equipment into the wall, and except for occasional damage caused by voltage spikes and surges, that equipment generally works. It's only when you compare the sound of equipment supplied raw AC with their sound on a diet of regenerated AC that you realize that such a system can sound better: more like real music and less like an electronic reproduction of same. This is what the PS Audio Power Plant Premier delivers. I wouldn't want to be without it.

PS Audio
4826 Sterling Drive
Boulder, CO 80301
(720) 406-8946