ExactPower EP-15A Power Conditioner 
Home Theater AC Power AC Power
Written by Bryan Southard   
Thursday, 01 August 2002

The ExactPower EP15A is a power component designed to regulate and improve the quality of the AC power that is supplied to your audio/video electronics. Most people simply purchase electronic components and plug them into the wall, never even considering that the performance of their A/V systems could be severely limited by the quality of the power that their homes provide. The ExactPower EP15A is a product designed to address this issue directly. The EP15A physically measures 17 inches wide, 14 inches deep, has a 2U rack height of three-and-one-half inches, and weighs a solid 30 lbs. The EP15A provides 1,800 watts of regulated power and provides eight high-quality receptacles for connecting you’re audio/video gear. The front-display exhibits output voltage but can be toggled to display output current or output power if desired. The EP15A sells for $2,499.

I give the aesthetics of the EP15A a high grade, with its sculptured front bezel complete with rounded corners and nicely fitting cover. This unit looks great, is reasonable in size, is rack-mountable and looks like a piece of fine electronics rather than an industrial power junction box. My only complaint about the fit and finish is that the cover sounded tinny when tapped, perhaps needing a couple additional screws to secure it.

It is a fact that nearly every home suffers from the effects of less than excellent AC power – especially in California, where I reside. This might not be readily apparent, because your hair dryer and toaster will still function without pure AC, but your A/V system will suffer. Whether you have a $15,000 system or a $150,000 system, the improvement to your sound and video when supplied clean, quality power is nothing short of dramatic. Power improvement devices are no longer tweaks for audiophiles, but rather intelligent electronic components for anyone that wants to reap the most from their beloved A/V gear. The problem that plagues this sector of the audio/video industry is the lack of consumer knowledge, along with the A/V retailer’s inability to demonstrate the benefits that these products provide. Admittedly, poor and ineffective power conditioners of days past have also added to the general consumers lack of confidence in such products. There are several approaches to improved power ranging from units that merely filter ugly power to very elaborate devices that regenerate waveform and even alter voltage and frequency.

Features and Technology
The ExactPower EP15A provides voltage regulation, maintaining a constant 120VAC output within one percent, when supplied loads of between one and 15 Amps and incoming voltages of between 95 and 130V rms. This is incredibly important, as power is like water traveling through a hose. Running lower or inconsistent voltages is like turning your faucet valve on only partially, then trying to hose down your patio. The EP15A is not current limiting the way that some AC products are. Once the maximum current of 46App has been consumed, output switches to the wall. Additionally, the EP15A has an internal, high-efficiency amplifier used to correct poor or damaged sine waves. It does this by taking the input signal and comparing it to a 60-cycle wave created by a reference sine wave generator (oscillator). Then its comparator circuit identifies differences in the wave and proceeds to use its internal Class D amplifier to make the repair. It does not regenerate the sine wave; it simply fixes it. This is a key to understanding its efficiency. When untreated waves are viewed from an oscilloscope, you will see that the tops of the waves are consistently damaged. The damage occurs at the peak, the location that produces the highest voltage. This damage limits available power and certainly the duration of peak voltage. By correcting the peak, you achieve more consistent power and much lower impedance. This design is very attractive for its inherent simplicity and efficiency. Many AV industry friends, whom I have told about the review, say that the ExactPower seems just like the PS Audio Power Plant products, but they are understandably mistaken. The PS Audio Power Plant is a power-regenerating device that takes the raw AC power from your wall, converts it to DC, then using a DSP-based reference waveform generator, creates an entirely new waveform, both regulated and low in distortion. Additionally, the PS Audio Power Plant products have MultiWave capability and other features that significantly differentiate the two design philosophies.

Music and Movies
Throughout the time that I auditioned the EP15A, it provided improvement to my system void of negative side affects. For example, the entire Beatles Abbey Road release (Apple Records) was a musical awakening. In the cut “Here Comes the Sun,” the images became much less bloated and took on a liquid, unveiled presentation. Vocals were more present and there was greater separation between the guitar and vocal accompaniment. Songs like “Maxwell’s Silver Hammer,” were transformed into very clear and lively musical events that had sounded a tad constrained and clouded before I installed the ExactPower EP15A.

I recently moved into a new home and had been running untreated power while trying to dig through the many boxes to find and connect my Richard Gray’s Power Company 400S’ that I have been using for reference. As I connected the EP15A, its effect was stunning. Immediately, images appeared more detailed and less forward. There was a huge reduction of unnatural bloom and artificial sonic puffiness. Musical images were less strident, yet very immediate. This is more commonly referred to as audible transparency. There was also a lack of noise that left the music sounding more pure, less veiled and more realistic.

From vocalist Alison Krauss, and album Now That I've Found You (Rounder Records) on a song that takes my breath away “Oh Atlanta,” the difference was as shocking as a February swim in the Arctic Ocean. Krauss’ voice beamed with much improved detail and definition. There was additional resolution and the focus was profoundly tighter. She stepped from the studio and into my listening room for a personal performance with the ExactPower plugged in. This difference was not merely something that would be discernable only to professionals with trained ears. This was an improvement that recent houseguests of all backgrounds were able to hear immediately. In direct comparison to the three RGPC 400Ss that I typically run, which cost $795 per unit (for a total of $2,400), the EP15A provided greater instrumental separation, quieter passages between notes and improved all-around detail.

Video suffers equally from poor or insufficient power, as its current demand is extremely high. When video sources are starved of the necessary power they require, symptoms can range from washed-out color to lack of contrast. With CRT projectors, you can even experience conversion shifting and other very difficult issues, depending on the severity of your power problems. Because of my recent move and the fact that my reference video system has yet to be re-installed, I packed up the EP15A and headed to a local retailer, who agreed to allow me to connect the EP15A through the front video projection system, in this case a very worthy Sony G90 nine-inch CRT projector. This test was equally dramatic, as images became immediately brighter with sharper edges and enhanced three-dimensionality. Before trying the ExactPower on the G90, the video image at the dealership looked incrementally more distorted and confused. With the EP15A, the image looked clearer and more resolved. In the movie "Dinosaur" (Walt Disney Home Entertainment), the segment in which the baby dinosaur emerges form the egg exposed much-improved, lifelike details such as hair flowing in the wind. These elements were finer, more realistic and better defined with the EP15A connected. No A-B comparison was necessary; the EP15A was an obvious improvement. Colors were brighter, focus was improved, blacks became darker, and edges were notably more true to life.

Back at home, I took the ExactPower from my reference A/V system and placed it in my more moderately-priced living room theater. This was an important test to determine whether this was a product best suited and limited to high-priced A/V systems, or whether it was a worthy investment for more affordable systems. Listening to the rock classic Paper Money, Montrose’s second release (Warner Bros), and the song “Connection,” Sammy Hagar’s voice had much better definition and clarity. Occasional crunch in his vocal cords identified a solid resolution improvement. The guitar had improved timber, again providing more transparency and dramatically better sonic separation. After connecting this system, a setup that has a retail value of below $6,000, I would only recommend it for systems in the $10,000 and up range, despite the improvements it made. Why wouldn’t I recommend it for everyone’s system? The answer is relative value. The ExactPower wont make a $699 receiver sound like a $2,999 Anthem AVM20 or make your old CD player sound like a DVD-Audio player. However, if you have a pretty strong AV system in the making, improving your power situation is likely to unlock a not inconsequential amount of performance for you that you currently do not have.

The Downside
The EP15A is built very nicely, but the less than solid top cover separates it from the build quality of the very best. The EP15A also provides protection from power surges but not from lightning strikes. This is an advantage of the Richard Gray’s Power Company products, which I ultimately used along with my ExactPower EP15A during the review period. Additionally, because The EP15A is active and subject to possible electronics-related problems, you are forced to rack or stand-mount the unit. This is a particular concern when dealing with ceiling-mounted video projectors, as you are then forced to run a power cord to the EP15A. Both the RGPC products and PS Audio Ultimate Outlet are passive products that allow you to bury them into the ceiling or attic.

The ExactPower EP15A is smartly designed both electronically and mechanically. It burns little power, is extremely efficient and provides sizable sonic and visual improvement. Its price point is such that it is a viable consideration for systems costing from $10,000 to mega-systems costing $100,000 and more. It has the power capacity to handle the biggest of amplifiers and enough receptacles to plug in most, if not all, of your A/V gear. When compared to the previously reviewed PS Audio P600, it does not match the P600’s ultimate performance. I found that with the properly selected waveform, the P600 supplies quieter passages, greater dynamic range, and slightly more transparency however the P600 does not have the available power to run many amplifiers that I owned and auditioned. The EP15A is smaller and much more efficient than the P600. For direct competition, you would need to consider the PS Audio P1200, a unit that is as big as a storage trunk and burns enough power in idle mode to light much of your house, not to mention having a price tag that is almost twice that of the EP15A. If cost and size were not a consideration, perhaps the P1200 would be my choice, but for my room, system and budget, the EP15A makes considerably more sense. It runs much cooler, consumes less power, fits in my rack and performs magnificently.

If you are ready to hear and see a discernable difference in your system, give ExactPower a shot. To this reviewer, who has danced the dance with the best AC power products on the market, passive and active, the ExactPower EP15A is the queen of the prom.
Manufacturer ExactPower
Model EP-15A Power Conditioner
Reviewer Bryan Southard

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