Quote:
Originally Posted by jdandy
nsgarch.......Just for informational purposes, the new PS Audio Power Plant Premier AC regenerator operates at 85% efficiency, which is a substantial improvement over their older designs which were in the 50% efficient range, and as such were unacceptable for me. The new PPP is only warm to the touch, even under substantial load, and though they are equipped with thermostatically controlled fans, I have never heard any of my three PPP's fans turn on.
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Hi Dan. Well that figure (85%) is, to be diplomatic, somewhat
conditional 
- as hinted at in the recent Stereophile review: "Like earlier Power Plants, the Premier has a fan, but the amp runs far more coolly than its predecessors; the fan isn't expected to come on unless there's considerable sustained current draw." In other words, the
less of its 1500W capacity you use, the higher the efficiency of the unit. This (sliding efficiency curve) is achieved by the use of a "tracking power supply" which provides
less power when the total equipment/system draw is low. Exactpower doesn't have to do any of that stuff. It's basically passing the wallpower AC right through after surgically cleaning up any glitches it finds.
Bottom line, is that to eliminate noise, the PPP still still uses standard conditioning/regenerating circuitry, and can only make new AC to the degree it discards about 50% of the wallpower. So it's designed to make only as much
really new AC as called for, which helps. But it still has to employ a Class A-B amp, whereas the EP, by contrast, uses a simpler and more efficient (at low 60Hz frequencies) Class D amp, just as powered subwoofers do.
Don't get me wrong. I'm not saying the PPP won't do the job. But it
IS old technology any way you slice it. And more costly to operate.
- Neil