General Asylum: REVIEW: Accuphase PS-1200 Clean Power Supply Power Conditioner/Surge Protector by David Spear

Background

I wasn't convinced that a power conditioner could make a significant difference in my situation, since I live in a rural area, use dedicated AC lines to the outlets in my listening room, and have never noticed any hum, buzz, crackle, pops, or any other AC-related nasties in my system, even with the volume control turned up well past my normal listening levels. I should also mention that, although the sonic differences between various interconnects and speaker cables are quite obvious to me, I really didn't hear too much of a difference when I upgraded all of my power cords to single-crystal copper Harmonic Tech Pro AC11's a couple of years ago. That said, adding an Accuphase PS-1200 Clean Power Supply to my system has made me a believer in the benefits of power line conditioning.

Practical Aspects

The PS-1200 is a large and heavy unit, measuring 9 1/2 [H] x 18 11/16 [W] x 20 [D] inches and weighing 82 pounds. Given its dimensions and weight, it may be difficult to accommodate in a standard equipment rack. It is quite attractive, with a champagne-finished front panel sporting a small, round meter in the center, a hefty power switch on the left side, and a knob to switch the meter display on the right. (The meter can be set to display the power draw, input voltage, output voltage, input distortion, or output distortion.)

Basically, this power conditioner regenerates a perfectly sinusoidal AC waveform, similar in principle to the PS Audio Power Plant units. However, unlike the Power Plants, the PS-1200 does not regenerate the AC waveform from DC. Instead, it continuously monitors the input waveform and compares it against an internally generated sine wave reference, adding or subtracting power as required. As a result, the PS-1200 is very efficient and is able to deliver 1500 VA to its 7 AC outlets (5 on the back and 2 on the front). In my system, the PS-1200 is easily able to drive my CD player (Accuphase DP-65V), preamplifier (Accuphase C-265), and power amplifier (Accuphase P-550; 270 WPC @ 8 ohms, 420 WPC @ 4 ohms). At quite loud listening levels, the PS-1200 runs at about 1/3 of its rated continuous output capacity and becomes warm (but not hot) to the touch.

The practical advantages and disadvantages of this unit are summarized below.

Advantages: Attractive design, outstanding build quality, completely silent operation, minimal heat generation, high output rating (able to drive high-power amplifiers), nice meter to prove it is actually doing something, and (couch potato bonus) you can turn your entire system on and off with a single switch.

Disadvantages: Expensive, big, heavy, no adjustable delay for the various AC outlets, the meter (which is rather brightly lit) can't be dimmed or turned off, and the outlets on the front (though possibly convenient at times) detract from the unit's otherwise elegant appearance.

The Sound

When I first plugged everything into the PS-1200 (using Harmonic Tech Pro AC11 power cords throughout), the fact that there was a difference was immediately apparent, but it took me some time to decide what exactly was happening. (I should mention that the level of distortion in my AC power line was about 4%.)

Imaging, soundstaging, transparency, air, dynamics, speed, tightness, spectral balance, etc., etc. were essentially unchanged, but the overall character of the music was somehow different. Initially, I was kind of disappointed because it seemed that the music was a bit less exciting. However, as I continued to play CDs, I noticed that vocals sounded much more realistic, as though the voices were coming from real flesh-and-blood humans rather than from abstract points in space in the soundstage. The ability to pull individual voices from grouped vocals was also significantly improved.

I don't know if I really have a handle on the sonic differences yet, but the music is paradoxically both smoother AND more clearly defined, resulting in a heightened sense of realism. I guess that the best I can do at this point is to say that the music sounds somehow less "mechanical" and more "organic" or (to steal the adjective used by Jonathan Scull in his review) more "refined".

Summary

Adding an Accuphase PS-1200 Clean Power Supply has resulted in a significant improvement in the overall musicality of my system, helping to bring it another step toward the ultimate (and ultimately unachievable) goal of musical nirvana. I guess that whether or not this degree of improvement is worth the cost ($8000+) is open to debate, but I suspect that many audiophiles will find the PS-1200 to be a worthwhile addition to their systems.

REVIEW: Accuphase PS-1200 Clean Power Supply Power Conditioner/Surge Protector Review by David Spear at Audio Asylum