"...the surprising EP15A held its ground against much more expensive references. I could be happy replacing $6,500 worth of conditioning components with a single EP15A. It proved to be formidable indeed."
By Doug Blackburn
Widescreen Review (11/03)
REVIEWS
The EP15A analyzes the AC power line, throws away any part of the AC power that isn't "perfect," then fills in the portions that have been thrown away with power generated by the internal class D switching amplifier. If our AC power has 5 percent distortion, not an uncommon thing these days, the EP15A keeps the 95 percent that is "good" and replaces the "bad" 5 percent with clean power generated by a high-efficiency class D switching mode amplifier. Switching mode amplifiers are especially well suited to operating at lower frequencies, like the 60 Hz AC power frequency. Switching amplifiers are typically 80 to 90 percent efficient in power usage, while conventional amplifiers are only about 50 - 60 percent efficient. Retrieving all the power needed to operate a typical home theatre system would require a product much larger and much more expensive. Products that generate all of the AC power they output generate many times the heat generated by the EP15A.
The EP15A is neither a power conditioner, nor a power re-generator. It is somewhere in the middle. It rids the AC power of harmonics and noise and generates replacement power for the portions of the AC power that were removed in the process of eliminating power line harmonics and other distortions. In addition, it insures the output power is always 60Hz and the rms voltage is always 120VAC.
One of the technologies used to make the EP15A's voltage regulation work effectively is "feedforward" - an improvement on feedback that you may be familiar with in amplifiers. In order to reduce distortion in the output signal, most amplifiers employ some degree of feedback. Essentially, a wave from the output of the amplifier is run back to a "comparator" circuit that compares the output waveform to the input waveform. If there is a difference, an instantaneous correction is applied to the input side of the amplifier. If the comparator circuit can detect a difference at the output, it's really too late to completely stop the error, isn't it? Feedforward puts the correction up front on the input side. The input signal is adjusted before it is amplified so that the output is "perfect" by definition. This is easier with a product that has only one input frequency - like the AC power line.
Keep in mind that your AC power line is nothing more than a very powerful bass audio signal. It is always 60 Hz and ideally should be a perfect sine wave with (approximately) 1170 volt peaks that result in 120VACrms (rms = root mean squared, a complicated way to "average" the voltage when it is changing from instant to instant). An internal reference signal independent of the AC power line defines what the power line should look like if it was perfect. That internal reference can then be used to determine the 5 percent of the power line to get rid of and the 95 percent to keep (your power line might be 2 percent bad and 98 percent good or some other percentage). The feedforward circuit's response time is critical to producing the lowest possible distortion at the output. The method used in the EP15A has nearly unlimited response speed. This allows the EP15A to remove distortions at essentially an frequency likely to be present on the power line.
The result of all the comparing and high-speed restoring that goes on inside the EP15A is a constant output voltage with very low impedance and a "text book perfect" sine wave. The low impedance means it is easy for your components to "pull" power from the EP15A. Think of low impedance as a bigger drinking straw – it's hard to suck much out of one of those tiny cocktail straws if you're thirsty, but it's easy to get a big gulp from a pair of big straws.
Putting the EP15A into service is easy enough. Plug all of your system components into the eight electrical outlets, connect the EP15A to the wall, and press the big button on the front panel.
[ Note: We could not have said it better if we'd written this product description ourselves. The above introduction is excerpted from Doug Blackburn's review in Widescreen Review, issue #78, Nov 2003. We recommend you go to the Reviews section on our site to read the entire article.]
A primary technical feature of the EP15A is Reserve Power. ONLY ExactPower has Reserve Power, and it makes a huge difference in why the EP15A outperforms other "clean power" units. For an interesting, in-depth discussion of Reserve Power, please click on this link -- Reserve Power.
Click here to read what people are saying about ExactPower...
EP15A Features
Patented sub-cycle regulation corrects voltage and waveform virtually instantaneously
Patented, high-speed, feed-forward current technology
Reserve Power? allows amplifiers to deliver their full potential (46 amps peak to peak)
Up to 1300 watts of power
Surge protection – active and passive
97% efficient, high power output, very low heat dissipation
Extremely low output impedance
EMI / RFI filtering with digital isolation
Eight isolated, full-contact Hubble NEMA receptacles (USA model)
Two-line VFD can display voltage, current, power, or over-temperature
UL/CSA and CE approved
Rack mount option
Available in silver or black
Designed and manufactured in USA
3 year warranty
EP15A Specifications – 120V model
Input voltage range: 90 to 140 Vrms
Nominal output voltage: 120Vrms ±0.5%, 60Hz, 1 to 15 Amps
Bandwidth: 2.0 kHz
AC signal-to-noise: –110dB
THD: <0.2%
Output impedance: <0.5 Ohms
Outputs: 8 Hubble NEMA receptacles
Surge Protection:
passive: 140 Joules 6,000A
active: 120VRMS to 160VRMS
Power rating – continuous operation: 1100–1300 watts (load dependent)
Low-pass filter: Dynamic, not passive
Protection: Over Voltage, Over Temperature, Over Current, Under Voltage
Peak repetitive output current: 46A peak to peak
Weight: 30 pounds
Dimensions (WxHxD): 17? x 3.50? x 14.2?
Power capability depends on the quality of the electrical service feeding the AC outlet your ExactPower unit is plugged into. This includes the quality and load ratings of fuses and circuit breakers in the line, even the quality of the wiring.
The table below provides the information on the power delivery of the EP15A for a given line voltage:
If the AC at your wall socket is... The EP15A can produce...
120 volts 1,650 watts
115 volts 1,550 watts
110 volts 1,500 watts
105 volts 1,450 watts
100 volts 1,400 watts
95 volts 1,300 watts
Warranty: ExactPower offers a limited warranty against manufacturers defects and workmanship for a period of three (3) years.
Exact Power UltraPure 1, brand new with full warranty from authorized dealer
List price: $1,999.00; SELL: $1,799.00 $1,599 includes USA shipping.
Exact Power EP15A, brand new with full warranty from authorized dealer
List price: $2,499.00 ; SELL: $2,249.00 $1,999 includes USA shipping.
Crane Enterprises and Crane Home Theater.
