Product Review - ExactPower™ 2000 AC Line Purifier - October, 2000

Stacey Spears



ExactPower 2000 AC Line Purifier

Capacity: 2000 Watts (RMS)

Outputs: 6 AC Outlets (120 Volts RMS)

Size: 17" W x 3.5" H x 13.2" D

Weight: 35 pounds

MSRP: $2,495 USA

Atlantis Power Quality Systems, Inc., 9411 Winnetka Avenue,
Chatsworth, California 91311, USA;
Phone: 800-773-7977; Fax: 818-886-0504; E-Mail  [email protected]; Web


Equipment designed to improve the performance of your audio and video system has been around for a long time. From what I have experienced, up until recently, they have offered little, if any, improvement (at least in the equipment that I have experience with).

One of the first really useful products was the asymmetrical (balanced) power transformer from Equi=Tech (ET), which we reviewed.  Quickly following on its heels was the PS Audio Power Plant (PP) AC regenerator, which we also reviewed, and now comes the ExactPower™ (EP).

The design of the EP actually started a few years ago. Atlantis Power Quality Systems Inc. is responsible for the EP. Atlantis was approached a few years back by a company to create a voltage regulation system for large-scale power (non-audio applications), at a fair price. The voltage regulators that are available to handle such demands retail well over $20k. Before Atlantis could build such a beast, they wanted to build a smaller, proof-of-concept product. The ExactPower™ was born.  Greg Scott, who is one of the ExactPower engineers, also happens to be an audiophile and saw a unique opportunity for their technology.


For what the EP is capable of, it comes in a very unimposing black box. The EP is rack mountable and weighs in at 35 pounds.  For such a small size, you might be thinking that it has a limited output, and you would be correct; it is limited to 2,000 watts!  The EP is capable of regulating the voltage to 120VAC when the incoming AC drops as low as 80VAC or as high has 140VAC.  Unlike the PP, which completely regenerates the AC, the EP merely adds to or subtracts from the incoming VAC to provide a clean regulated output.  It's a very efficient approach.

The front panel is all black with a single power switch and three LEDs, red, green, and yellow. Red indicates that the incoming voltage has risen above 140 volts, and the outputs are turned off. The green means that everything is A-OK. Yellow means that the incoming voltage has dropped below 80 volts, and they have deactivated their voltage regulation.

The back panel contains six AC power receptacles and an IEC female connector for a power cord.

I really wanted to include some photos of the inside of the EP and detail exactly what it does, but at EP's request, I have not.  They are still in the patent process phase and I fully respect that.  However, I am including the same photo here that you will find on their website that shows part of the EP internal chassis.

I mentioned earlier that the EP simply adds or subtracts to correct the AC.  This is done in real time by monitoring the incoming AC and correcting it on the fly.  It has a built-in reference of what the AC should be, i.e., a perfect 60 Hz sine wave. If the incoming voltage has a few blips here and there on the sine wave, the EP removes them. If the edges are squared off (harmonic distortion), the EP corrects them.  There is a similar product on the market from Accuphase called the PS-1200.  I have not seen nor heard the PS-1200, but it retails over $8,000.  Not only is the EP less expensive and capable of delivering more power than the PS-1200, but it also weighs less than half.  The PS-1200 weighs a massive 82 lbs.


Life Saver

I had a brand new amplifier plugged into the EP. I had listened to the amp the night before for about 2 hours. I got up the next morning, turned the amp on to warm up, and hopped in the shower. Upon returning from my morning ritual, I noticed that the amp and other equipment that were plugged into the EP were off. I walked over to the EP and noticed that it too was off. I flipped the EP power switch back on, and one of the speakers started freaking out. The cones were moving in and out quickly and a loud whining noise emanated through my room. I rushed over and powered off the amp, next thing you know a large cloud of white smoke came pouring out of the amplifier.

It turned out that one of the amp channels shorted, and it had started to oscillate. This sent a large surge back to the EP, and its internal 15-amp circuit breaker tripped. This is the correct behavior of the EP, and had the EP not been there, that surge would have gone back to the main breaker panel. If the EP had not tripped, who knows what may have happened? The EP is still working as good as the day it arrived.

Time for Testing

I always have a great time trying to stress out a product, and nothing beats a Sears Craftsman 4 Amp industrial drill for this purpose!  One of the key features of the EP is voltage regulation.  Devices, like the Sears drill, are as tough as they come for screwing up the line voltage.  The inrush current from the initial trigger pull is enough to dim the lights in the room.

I tried a couple of different scenarios, and the EP was able to keep up with the demand in all cases.  First was to plug the drill into the wall and a table lamp into the EP (and this is no wuss lamp; it's a 500-watt halogen lamp, aka indoor torch!)  The light did not even stutter.  This tells me that the output of the EP is not influenced by its input, i.e., outside sources.  Next was to plug the drill into the same EP AC output as the lamp.  Again, the EP refused to back down.  For the record, plugging both the lamp and drill into the same wall outlet had the lamp dimming as I repeatedly pulled the drill's trigger (much like revving an engine). I did have my handy-dandy voltmeter plugged into one of the outlets so I could watch the voltage.  The voltage was 117 when I started and would occasionally drop to 116 but mostly it stayed at 117 volts.

A real world scenario

For a more home theater realistic scenario, I had three Meridian DSP-5500 loudspeakers plugged into the EP.  Each Meridian speaker is powered with four built-in 75-watt amplifiers, driving four cones.  The maximum rating on each speaker is 600VA.  If one were able to have all three speakers running at full load, they could potentially draw 1800VA from the EP.  That's an awful lot of power to provide.

So, I wanted not only to drive the speakers at full load, but also to have them go from zero to full output in an instant.  Enter the awesome power of classical music.  I chose Copland's "Fanfare for the Common Man", Louis Lane and the Atlanta Symphony Orchestra.  This is an early Telarc CD before the bad habit of compression now used in many CDs.

For the test, I plugged a Tektronix TDS750 into the EP to watch the sine wave and output voltage.  I set my surround processor in Trifield so that all three front channels would be running.  I next set the volume on the processor to 87, which corresponds to the THX reference level of audio output.  The final touch was the earplugs to prolong my hearing, as I would never actually listen to this three minute and fourteen second torture test at such a loud volume.  The waveform never clipped, and the voltage from the EP never sagged, even though the room (maybe the entire neighborhood) rocked from the power of Copland.  I also happened to have a FLUKE meter (not the fancy power meter, just your better than average volt meter) plugged straight into the wall, and the incoming voltage did sag.

None of the above actually tells you anything about what it does for the sound.  I just went through it to try and disprove their claims, which I am happy to report that I was not able to do.  The most pronounced effect that I witnessed in the area of sound quality was an improvement in the bass.  I used such artists as Paula Cole, Ani Difranco, Jennifer Warnes, Aaron Neville, and Kid Rock.  In each case, the bass was better defined and extended deeper.  It was especially noticeable at very high output levels.

I tried just plugging my CD player into the EP and everything else into the wall.  I really could not perceive any difference.  But, once I plugged the power amps or powered speakers into the EP, that's when the improvements were really noticeable.  They were not subtle either!

What I noticed on video was an improvement in the ability to hold black at black when the average picture level changes.  I used the Avia overscan bounce test pattern to verify this.  This pattern switches between a black background and a white background.  The pattern has markers all the way around that let you see just how much overscan you have.  On poor projectors, the amount of overscan will change based on whether the background is black or white.  This is usually the result of a poor power supply in the display device.  The EP did not completely solve the problem, but it did reduce the amount of change.  I tried this on my parents' Mitsubishi 1st generation (can't remember the model # off hand) 65” HDTV.  This TV is as bad as it gets when looking at the overscan bounce pattern.  The EP made a very large improvement, so much that my parents attempted to bribe me into letting them keep the EP. No such luck, the EP is still with me.

Did the EP improve the colors or make the image more 3D?  No, and neither has any other power product that I have tried.  Let's think about that; if the color level did change, I would have to re-calibrate it right back where it belongs (to the standard).

How dedicated are you?

A typical breaker box in the garage has 240-amps coming into the box, and is split up into two 120-amp phases.  Each side or phase may have several 15 or 20-amp breakers.  One breaker may actually have an entire room or two wired to it.

Many audio/videophiles have long been installing dedicated circuits (20-amp) breakers for each outlet in their A/V room because it is believe to be the best solution.  A dedicated circuit does not guarantee clean power. When you have a 20-amp circuit, all this means is that you can pull up to a 20-amp load before that circuit will trip (shut off). All of these circuits are in the same box and really share the same power.  There is some isolation between breakers, but it's not as great as people believe. That does not mean you shouldn't install a dedicated circuit, since home theater these days draws a lot of power. Just remember that it is not clean AC, and it is often much different than 120 volts.

Let me give you an example, I borrowed a chop saw a while back while working on some automated blinds for my theater room.  That saw was plugged into a circuit that the garage was also on. Every time I pulled the trigger and the saw started up, all the lights in the house would dim.  All of these lights were in fact on separate circuits, but like I said, they are all tied together.  Every time the compressor in your refrigerator kicks in or the washer and dryer are in use, it may cause your AC to sag.  Your house AC is also shared with your neighbor's house, and whatever dirty electrical equipment he has will contaminate your AC.

I am telling you this because I want you to realize that dedicated circuits are not all they are cracked up to be.  By using the EP, you ARE going to have approximately 120 VAC at all times, day or night. You can have your fridge cooling, washer cleaning, dryer drying, chop saw cutting, and the EP will still output clean 120 VAC.  I have my entire A/V room on one EP circuit.

What about other power toys?

I tried using the EP with a few other power products to see how they worked with each other. I came to the conclusion that the EP is capable of not only improving the sound from power amps and TVs, but it also made a sonic improvement to the P600. I also tried placing the P600 before the EP, but the results where not very good. In fact I was able to make the P600 shut off while playing Copland at very loud levels. PS Audio Power Plants achieve similar results but take very different approaches.  As I have said before, the PP regenerates the AC.  It also offers the ability to change the frequency of the AC from 50 or 60 Hz to anything from 50 Hz up to 120 Hz in 5 Hz increments.  PS Audio also now offers what they call MultiWave.  I happen to own a P600 (equipped with MultiWave) and a P300, and I run both units at 60 Hz.  The PP also outputs balanced power, which I am a fan of.  The EP is capable of supplying a lot more power, and it uses a lot less power to do it.  It keeps the AC regulated regardless of input AC and corrects the sine wave just like the PP, but it does not change the frequency like the PP products, nor does it offer balanced power.  I am still not sold on the frequency changing capability and I don't use it on my PPs.  Others have reported wonderful results when changing the frequency, but I have not experienced those results in my listening tests.

In order to get balanced power with the EP, I combined it with the Equi=Tech balanced power transformer, and I really liked the results.  I plugged a 1.5 kVA ET into the EP with great success. The EP when combined with the ET outperformed the PP on both source gear and power amps/TVs. The cost of the two equal the price of the upcoming P1200, but the combo is still capable of delivering more power to your gear and it uses a lot LESS power to do so (i.e., it's WAY more efficient).


The EP is a power product that truly works, and it is built on sound engineering principals.  It's very efficient in the way that it creates the power and offers the best bang-for-the-buck regulated AC you can buy today.

Paul Knutson will be doing a follow-up shortly that goes into more detail on how The ExactPower affected his music listening.


- Stacey Spears -


Manufacturer Response:

On behalf of everyone at Atlantis Power Quality Systems, makers of the ExactPower 2000 series, and everyone here at Perpetual Technologies and (the world-wide distributors of this product), we'd like to extend our sincerest thanks to Stacey Spears for his fabulous, premiere review of this exciting product.

I can personally and professionally attest to the significant benefits of this product, covering every audio and video scenario we have tried it in. As someone very much involved with the initial launch of the PS Audio Power Plant, and now, this sensational product, I can say without reservation that, regardless of the PLC or “Power Regenerator” you may own, the ExactPower 2000 is a must have addition. The EP 2000 is THE solution for any requirement, as it acts as almost an “AC Front End” for any application. This is a cornerstone product that the rest of your system can be built firmly upon.

We have tested the EP 2000 next to every comer, on its own, and also as a “Front End”, and we sincerely believe it is the best of the genre in any application. We were very gratified to see that Stacey felt the same when he used the EP 2000 in front of the PS Audio products for “sonic improvements” (to the P-600), and in conjunction with the Equi=Tech to generate a balanced power result to great effect. How can we argue with the result? “The EP, when combined with the ET, outperformed the PP on both source gear and power amps/TVs”. This pretty much sums it up.

I urge your readers to visit the ExactPower web site and spend some time going through the material… especially the article entitled Principles Of Grounding by Mr. Bill Whitlock, President of Jensen Transformers, Inc. and Principal of Atlantis Power Quality Systems, Inc. Additional down-to-earth details of the patented “feed forward AC power-correction system” that is the heart of this product are explained.

With sincerest thanks,

Mark L. Schifter

President and Founder

Perpetual Technologies /


© Copyright 2000 Secrets of Home Theater & High Fidelity
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