Powerline Accessory Reviews

PS Audio P300 Power Plant: A major highlight of my life as an audiophile was to have the Mark Levinson No.32 Reference preamplifier spend a few weeks in my system last fall. Reviewed in the January 2000 Stereophile by Jonathan Scull, the magnificent No.32 enabled my music to communicate more directly than I had ever experienced from my system.

Paradoxically, it was better in this regard than not having a preamp at all. A while back I bought an all-digital Z-Systems rdp-1 to control volume and digital source switching, so I could feed the output of the Levinson No.30.6 digital processor straight to the No.33H monoblocks. While having an rdp-1 in the chain is undoubtedly the most transparent window between CDs and my ears, sometimes the faults in the recordings are laid a little too bare.

Despite being entirely solid-state, the No.32 combined the transparency of the rdp-1 with the inherent sweetness of tubes, and did not suffer from the cloying colorations I have found endemic with thermionic circuits, and also seemed to present the music in a more holistic manner than the rdp-1. (I know, can't be possible, right?)

After the No.32 went back, I returned to the Levinson No.380S, which has taken pride of place in my system since I reviewed it for Stereophile in November 1997. As you can read in my sidebar accompanying Jonathan's No.32 review, while the '380S is still a superb preamp, it adds a slight "gray" character to the sound of my system. It took my experience with the No.32 and the rdp-1 to reveal this, but after the '32 had been returned, I could still hear it. So with the rdp-1 almost too revealing and the '380S not revealing enough, what was I to do? (Buying a '32 was out of the question, given an impending house purchase.)

A major feature of the Levinson No.32 is its use of AC regeneration to provide its power supply with absolutely clean AC. Proving the power of synchronicity, almost to the day the Levinson shipped out, PS Audio's Paul McGowan sent me a sample of the Power Plant 300 (footnote 1), which had been reviewed by Bob Deutsch last December. As the PSA unit also provides AC regeneration—see my interview with McGowan—I rushed it home to hear how it might affect the '380S.

Setting the Power Plant up didn't give any problems—no ground-loop hums—but its longer-than-wide proportions meant I had to place it sideways in my rack. The only component I plugged into it was the preamplifier.

Well, they say you don't know what you've got till it's gone. It was when I disconnected the preamp from the PS Audio and plugged the preamp back into the wall that the improvement the Power Plant wrought in the sound of my system was most apparent. With the Power Plant providing the juice, there was an ease to the presentation—a liquidity, if you will—that was seductive in the extreme. No, adding the $995 Power Plant to the $6495 No.380S didn't turn the Mark Levinson into the $14,950 No.32. But with the PSA set to output a clean 90Hz rather than 60Hz, I no longer felt the loss of the '32 so deeply. In fact, I can now live with the '380S for a while longer.

It sounds like a cliché, but the best way of describing what the Power Plant did was that the blacks became blacker. The contrast between the images of sound sources and the background against which they were portrayed was increased. If you've seen a good HDTV presentation, you'll probably agree with me that, once you've gotten over the unexpected acuity, it's the color saturation that grabs you. So it was with the PSA in the loop: instrumental tonal colors became more saturated.

Back in January, I drove out to Santa Monica for a long weekend to record Canadian pianist Robert Silverman in a complete cycle of the Beethoven piano sonatas. My plan was to use four mikes at 88.2kHz sampling and 24-bit resolution to allow for both CD and possible DVD release; so, as I packed the truck with everything I thought I might need, I grabbed the Power Plant. My four channels of dCS A/D converter and Millennia Media mike preamp were plugged into it for all four days of sessions.

When I got home and played back the 88.2kHz tapes, not only was the noise floor on the recordings the lowest I have ever achieved—the dCS/Millennia kit is inherently quiet—but the color of Bob's Bosendorfer SE piano seemed to be more deeply etched against the background ambience than I had been anticipating. His rendition of the "Appassionata" sounded gut-wrenchingly real, both in its dynamic contrasts and in its vivid-without-being-spotlit tonal quality (footnote 2). If the PS Audio Power Plant had anything to do with it, then, with my hand on my heart, I tell you that you simply must check this piece out for yourself.

Enough foaming at the mouth. Does the Power Plant have a downside?

One. Like all class-AB amplifiers, it has limited efficiency. Leaving it on all the time, as I do, is equivalent to burning a 300W lightbulb continually. Not only does this impact your electricity bill, it is not environmentally friendly. And because of this inefficiency, the PS Audio runs hot. (During the Beethoven sessions, it got very hot.)

But it is not the role of this magazine to pass judgment on issues other than sound quality. (I just know this statement will come back to haunt me.) In that regard, if PS Audio's Paul McGowan wants my sample of the Power Plant 300 back, he can pry it from my stiff dead fingers. I'm sending him a check!—John Atkinson

Footnote 2: Though these Beethoven sonatas will be initially released in Canada on a Canadian label, I hope very much to eventually be able to make some of them available on a Stereophile CD. It is perhaps the finest musicmaking I have ever been involved with.