Powerline Accessory Reviews

I can't remember a time when I wasn't concerned about power quality. I grew up around finicky, home-brew ham-radio gear and labs full of instruments, and with both, power-conditioning gear was standard fare. When I moved into high-end audio, it seemed obvious that power quality was important. As a result, I've experimented with a wide range of power-conditioning equipment, from simple ferrite loops to huge isolation transformers, and even exotic laboratory power supplies that could vary the voltage, frequency spectrum, and shape of the AC signal.

Considering that not that long ago there wasn't even a product category for balanced AC line conditioners, we seem to now enjoy a plethora of the critters. Cinepro offers the PowerPRO 20 (reviewed in Stereophile, November 1998, Vol.21 No.11). And Equi=Tech, which caters more toward the pro end of the field, offers one that I have yet to hear. Now Audio Power Industries weighs in with their own approach to the genre.

There never seem to be enough AC outlets, and when there are, they're not always easily accessible. I have two dedicated 15A duplex outlets at the power-amp end of my room, but a subwoofer and multiple power amps (up to three at a time) exhaust those facilities. What happens when I need to add a second subwoofer or other EQ? What do I do when I want to keep more than three amps cooking for quick comparisons?

Any difference that is at all audible must be treated as though it is huge!" John Atkinson declaimed, as Tom Norton and I rolled on the floor laughing. It was a slow day around the Stereophile offices, and the startlingly huge differences that our colleague was describing did strike us as rather piddling—so John began stentorophonically reciting rules from a mythical Guidebook for Audio Reviewers to gales of laughter all around.

Tweaks come and go. When a new one creates a buzz in audiophile circles, I generally prefer to wait and see if it's still around after the initial excitement has subsided. I'd heard about "audiophile" fuses some time ago, and although the likelihood of them making a significant difference didn't seem as farfetched as such tweaks as the "intelligent chip" or the "clever little clock," I didn't feel inclined to try them. I was persuaded otherwise by the confluence of two separate influences: a report by Michael Fremer, in the February 2007 Stereophile, that the HiFi-Tuning fuses produced a "subtle but noticeable" improvement in the sound of his Musical Fidelity kWP preamplifier; and an encounter at the 2007 Consumer Electronics Show with Robert Stein of importer Ultra Systems (the HiFi-Tuning fuses are made in Germany), who said that they produced a big improvement and offered to send me some samples.

In the November 2018 issue of Stereophile, Jim Austin reviewed PS Audio's DirectStream Power Plant P20 AC regenerator ($9999). PS Audio had sent me the less expensive DirectStream Power Plant 12 ($4999), hence this review.

Why use an AC regenerator rather than plugging components straight into the wall?

When I reviewed PS Audio's PerfectWave P10 Power Plant AC Regenerator,1 I found that it significantly improved the way music sounded through my system. I bought one. The main limitations I found with the P10 were its power—a maximum continuous load of 1200 volt-amps (VA, footnote 1)—and the number of AC outlets it provides: 10. When driving a 4 ohm load at even half its rated power, one PS Audio BHK 300 monoblock consumes 800W—and while 10 outlets sounds like a lot, I've run out more than once.