Exact Power EP15A/SP15A vs. PS Audio Power Plants

FWIW, I have the ExactPower 2000, which preceded the EP15A, and which I assume uses a similar design approach. All of my electronics (Denon DCD-1650AR CD player, Dodson DA-217MkIID DAC, Bryston BP-20 preamp, and Aragon 8008BB power amp) are plugged into it, and after one hour of listening to orchestral works on Thiel 3.6 speakers, when the heat sinks on the Aragon have warmed up, the ExactPower is still as cool as it was when it was turned on. More efficient? Yes, indeed. I am very pleased with it.

A_hayman, what about the sound, with vs. without? Did you compare it to any other PLC's?

Zaikesman, some years ago, when I had my system plugged straight into the wall, I had an unfortunate experience where a transient on the AC line locked up my CD player, sending a huge noise pulse through my system. I had to turn the system off and back on to restore operation. Although neither my system nor my ears were damaged, I didn't want to risk that happening again, so I started using a Tripplite LC1200 line conditioner. As I gradually upgraded my system (CD player, preamp, power amp, speakers, interconnects), I became increasingly suspicious about the effect the Tripplite was having on the sound, and I starting researching other PLC's.

The problem was that I wanted a unit that could accomodate my entire system, including my power amp, and that eliminated the Power Plants -- there was too much dissipation, and they are expensive for the amount of useful power that you get. Then I heard about the ExactPower unit, and the fundamental difference in approach between the Power Plants and the ExactPower: the Power Plants regenerate the AC waveform, and output it to the system, whereas the ExactPower does a real-time comparison between the incoming AC waveform and an internal sine-wave reference, and adds an instantaneous correction to the incoming AC before outputting it to the system. The result is that the Power Plant power dissipation is based on the output voltage times the current, while the ExactPower dissipation is based on the voltage difference between input and output times the current. This means dramatically lower power dissipation with the ExactPower.

This convinced me to give the ExactPower a try, and the result was a sound that was much smoother and more coherent compared to what I now recognized as the "rawness" I heard with the Tripplite. I did try some listening without the ExactPower (straight into the wall), and there was a smaller difference, but it still favored the ExactPower -- the sound was a touch smoother and more musical. In our neighborhood, the AC line is subject to frequent disturbances -- whenever our next-door neighbor's air conditioning turns on, the lights in our house dim momentarily! The fact that the ExactPower protects my system from this stuff without degrading the sound makes it worthwhile for me!

I hope I've answered your question.

Good listening!

Zaikesman, after I made my last post, I was listening to the Shostakovich 3rd Symphony, part of the 11-CD set on Brilliant Classics of the complete Shostakovich symphonies, conducted by Rudolf Barshai. As I listened, I was thinking to myself, "How would I describe the sound of this recording on my system to Zaikesman?"

The sound was wide open -- both focused and transparent. The soundstage was deep, and extended past the left speaker. Individual instruments, like the brass and bass drum, were precisely placed in the soundstage. Massed violins were smooth, and entirely without grain. Bass drum had impact without hangover.

Part of this is due to the components that make up the system, but they couldn't sound like this unless they had clean power. As far as I'm concerned, the ExactPower 2000 is doing its job, and I don't recall the sound being on as high a level without it.

Hope this helps.

Thanks A_hayman for your additional input on the EP. I will make an untested-by-me suggestion, based on experience with my own API Power Wedge Ultra, that you might want to check into auditioning EP's new matching BPT (balanced power transformer) add-on unit in your system. With my Ultra's switchable balanced AC feature, I have found that this can make at least as big a difference for the better as filtering the line, especially it seems with solid-state front end components (of course that's without power-factor correction as on the EP and PSA units - the PWU is strictly passive). The difference can be subtle at first, but once you've gotten used to it, running without balanced AC can make your system sound 'subtly' broken! In my rig, balanced AC fleshes out images more in three dimensions, with less grit and more juice, and hones transients to a knife-edge fineness with much less background veiling and more impact. Switch it off, and what you get is flat, drained, and mushy by comparision. Your EP doesn't give you this feature by itself (unlike the PSA PP's), and what I'm describing doesn't even include running my power amps balanced - something the PWU can't accomodate, unlike the EP BPT. Just something that's probably worth a listen...