PurePower APS PurePower 700 Power Regenerator 
Home Theater AC Power AC Power
Written by Ken Taraszka, MD   
Friday, 01 February 2008

Power is an elusive beast for the audio and video enthusiast. If you live in the United States, each and every AV component you have ever bought was designed to run on 120-volt 60 Hz power. Sure, they can function when your AC power doesn’t exactly meet this specification, but at a cost, and that cost can be quite pricey in top-performing systems. Many of us who are looking to the last areas of improvement in our home theater systems have run dedicated power lines to our rooms with hopes of limiting noise on the incoming AC, thus affecting our sound and allowing our components to get all the power they need. However, I live in Florida and, quite frankly, our power outright sucks. We frequently get spikes, over and under voltages, brownouts, and let’s not forget the noise seen, heard and felt all over the entire power grid from the eight gazillion air conditioners running nearly every day of the year. During storms, surges and power outages are common and don’t even get me started on the threat of lightning.

PurePower has been working to solve all the demons that can affect the power your components see. The subject of this review is the PurePower 700, a power regenerator that offers battery backup for short-term brownouts. Make no mistake, this unit is no simple power filter. It takes your incoming power, converts it to DC and then regenerates it into 120-volt, 60 Hz power, plus or minus three percent. Amazingly, all this is done with a 92 percent efficiency, thereby not limiting power to your high-demand components, such as power amplifiers. This product also protects your system from power sags, surges, over and under voltages, line noise, power frequency variations, switching transients and harmonic distortion. Power disturbances can potentially damage your sensitive hardware through either catastrophic failures or wear over time from excessive load on your components’ power supplies. The PurePower 700 can prevent these problems from happening.

The PurePower 700 offers eight Hubbell outlets and surge protection for two cable lines, as well as RG46 and RG11 lines, allowing it to protect an entire system. This model is the smallest offered by PurePower and can output 1000 watts of pure AC power continuously and 1500-watt peaks with 24-amp peaks to your components and allow battery backup for 20-plus minutes when necessary, all for $1,795. The PurePower units aren’t current-limiting, and in fact can deliver more current than your AC lines alone.

The PurePower 700 I received came to me double-boxed; the outer box was even padded to protect the inner one. Opening the inner box revealed another layer of protection in two half-boxes heavily padded to protect the conditioner, which was neatly wrapped in plastic. A small box inside contained the power cord and manual. Mine came in the black finish and it was gorgeous. The fit and finish was truly first-rate, even when compared to the likes of electronics from Krell, Meridian and Mark Levinson. The front is quite simple, with only two buttons, one for power and one that cycles through the display options, a small display and three lights for output, utility power and alarm.

The display has two lines that can show you the status of your unit: the first line shows when the unit is functioning normally or in bypass mode, which can happen during extended overload or internal failure, when you are on battery backup, testing or short-circuit, should the unit detect the situation in your system and overload indicator. Should your system draw more than the units rated power output, its response will vary. If it is a small overload of one to 10 percent, it can tolerate it for several minutes; larger overloads can be tolerated for 30 seconds, after which the unit will switch to bypass mode and go on utility power. The second line displays input and output voltage and frequency, current temp, battery level and load level. I must admit, I loved cycling through the display. It was interesting to see my actual power input. I found I frequently ran over 120 volts even during the day. I used the load percentage to judge just how many components I could run on this unit. Battery life is quoted as average of five to seven years. The batteries are replaceable through the front panel, so should you rack-mount the unit, you can do it all through the front panel.

The rear houses eight Hubbel outlets on the left rear, with an IEC power input in the center. On the far right are an RS 232 control port and a USB port that allows you to connect it to your computer as its APS. This is no lightweight piece of gear, weighing in at 34 pounds and measuring three-and-a-half inches tall by 17 inches wide and 19 inches deep.

Setting up the PurePower 700 was amazingly simple. I connected it to a dedicated 20-amp line run to my room for audio and video. The 700 conducted a brief self-test and swiftly entered standby mode. I turned on the power with the front panel button and connected my components. I put this unit to the test in my reference rig, which consists of a Meridian 861v4 AV preamp, a Meridian G98 DH transport, an Esoteric DV-50s universal player, a Toshiba HD XA2, a Sony BDP-S1 and PS3 and a Scientific Atlanta 8300 HD DVR. Power comes from a Mark Levinson 433 for the fronts and a Proceed HPA-2 for the surrounds. I am currently running four Def Tech Mythos ST speakers with the matching Ten center and a Paradigm Servo 15 subwoofer. The majority of the system is wired with Transparent Reference interconnects and speaker wires.

I first connected the PurePower 700 to my key source components, my Meridian 861v4 and G98DH player, as I didn’t want to overload it at the outset. Later, I checked the display to find I was only using six percent of the rated output power, so I added more components to it. In my system, I have programmed my Harmony 890 remote to keep all unused components turned off when not in use, so adding more sources didn't excessively tax the PurePower. I next added my Mark Levinson 433 power amp, which is rated for 200 watts per channel into each of the three channels. Quite frankly, this amp is a little more than this power regenerator is designed to handle, but I carefully turned it on and watched the meter to ensure I didn’t overtax the unit. When I had the amp connected, I was able to turn the system up to extreme levels in two-channel and only use a high of 67 percent of its rated output power. I was even able to unplug the PurePower 700 from the wall and listen to this system on battery power. If you want to impress your friends, try this trick, but only with a PurePower 700 in your system, or you will suffer untold potential damage.

Music And Movies
I have been doing a lot of listening to Jimi Hendrix’s Blues (MCA) disc. I’m a huge fan of Hendrix and am familiar with the disc, so it seemed a great place to start. Prior to adding the PurePower to my system, I sat down and listened to this album in my Meridian G98DH. Then I connected the PurePower to just the Meridian gear and I must admit I wasn’t ready for what I heard. “Born Under a Bad Sign” had improved detail and a more believable sound to it. My system is pretty revealing, but the addition of this device really took it to a new level. I then connected my Mark Levinson 433 to the unit, as well as all my sources, and went further. “Catfish Blues” is my favorite song from this album, and with the PurePower, it gave me an experience I won’t soon forget. Every note had more detail and a more natural sound to it than I’d heard in my system prior to adding the unit. Every lick of the guitar and rap on the drum was perfectly done, and Jimi’s voice sounded even truer than before. I was worried that amplifier would draw more power than this unit is rated at, so I gradually turned it up and checked the percent usage. Surprisingly, I was able to crank it to extreme levels without overloading the unit.

I moved onto Keb Mo’s Just Like You (Sony) on SACD in my Teac Esoteric DV-50s. I had often heard the DV-50s benefits from a power regenerator, but until now hadn’t tried one with it. I should have. “That’s Not Love” came through with more air and detail than before I added the PurePower to the system. Bass had more slam and immediacy to it, while each note of the guitar was more clearly portrayed. The resonance of the acoustic guitar on “Perpetual Blues Machine” was amazing, better and more lifelike than without the PurePower. “Just Like You” had full and rich bass, while the small details of the bells in the distant background came through more clearly than before the addition of the PurePower to the system.

I was pretty amazed at what this device did for the sound of my system, especially given its baseline. To see what effect it would have on the video side, I plugged my Sony KDS 70XBR2 rear-projection LCD HDTV into the PurePower and started playing some movies. I cued up Deck the Halls (Twentieth Century Fox Home Entertainment) in my Toshiba XA2 reference HD DVD player and was treated to excellent color and contrast right out of the box (don’t ask about the movie itself). I switched the player and TV from the PurePower to the wall outlets and easily saw less brightness in color and less contrast as well. When the PurePower was used, reds were deeper and richer than without it and the contrast from the many snow-filled scenes was better. I swapped the PurePower in and out a couple times and re-watched some scenes; the picture was clearly better with the PurePower in line. Adding the TV did significantly up the power usage and, playing films at high listening levels, I saw readings into the mid-80 percent range, but never felt the sound to be compressed or that the unit was being overtaxed.

3:10 to Yuma (Lionsgate Home Entertainment) on Blu-ray was my next film to test. The movie is filmed almost entirely in the plains and as such is full of oranges and browns. With the addition of the PurePower, the colors just seemed smoother. Watching the movie without the PurePower in the system seemed to make the varying shades irregular, while adding it back in made them seem more lifelike. Reds from blood were brighter and more real-looking.

Even my cable TV was improved with the PurePower 700 in line. I saw more natural colors with improved edge detail that was clearly obvious upon switching out the unit. Colors seemed more real, especially skin tones. The change was so substantial that it was as though I had changed the picture settings on my TV, but I hadn’t; I had just allowed my TV to reach its full potential. This was obvious on HD, as well as SD channels.

The Downside
The PurePower 700 isn’t designed to be used with a truly large system. This said, I was able to power my entire rig with it without a problem but, depending on your system, it may not offer enough output, necessitating one of their larger units like the PurePower 1050. Eight power outlets is a sizable number, but not enough for my large and complicated system, so I was forced to use a power brick to add my sources, display and amp. The front display is very helpful, although it is pretty small and can be difficult to read.

Not so much a downside as a side note: some of the most high-performance amps from the likes of the most expensive models from Krell (Evolution) and Mark Levinson use some form of power regeneration. Most amps would benefit greatly from a PurePower unit. However, at the elite level, you might bypass using up your regenerated power if you own one of the few amps that already regenerate their own power.

The PurePower 700 offers benefits you simply can’t believe until you try it for yourself. Improved sonic detail, video, protection for your entire system and the battery back-up allowing for proper cool-down of projectors and displays saving bulb life, and you have a product that will not be leaving my system. I had ordered some custom racks for my reference home theater system, and once I connected the PurePower 700, I called to add another shelf to my rack for the unit. I simply cannot imagine running a system like mine without a product like this. Once you get your power “off the grid,” you won’t ever want to go back.

Many power products are out there now for audiophile to buy, even a few power regenerators. None of them do everything the PurePower 700 does. Completely regenerating the power and offering battery back-up, as well as total system protection, make this unit truly unique and a must audition piece for anyone looking to improve an already good to great system. Should you wish to add more battery back-up, PurePower offers additional battery Power Packs that you can add as well, extending the run time when you lose power.

The level of improvement this added to my already exceptional system was akin to a total system upgrade; it did more than I could have imagined a power product could do. Add in all the protection, ability to run on battery power and the fact that I can safely use my system during our frequent Florida lightning storms without worry, and I think it’s a steal. I am keeping this in my system and recommend you get one, too.

Let me be clear, I think this is the single most powerful, effective power product currently on the market. For audiophiles at least, one unit is an absolute must, but I could see someone with demanding amps using a PurePower 1050 simply for amps and a second PurePower 700 for source components. For custom installers, I see the PurePower as a mandate for the design of racks. Keeping products from crashing and running power to them exactly to the specs of the particular gear is a way to cut down on service calls, as well as give the client the most performance for his or her money. In the end, this is the best, most performance-oriented AC power device we have tested at AVRev.com. I now use it in my reference rack, publisher Jerry Del Colliano uses one, and we suggest that, if you want the most from your system, you consider a PurePower 700 for your system also.
Manufacturer PurePower APS
Model PurePower 700 Power Regenerator
Reviewer Ken Taraszka, M.D
Power Regeneration Yes

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