audiophile aps

as reviewed by John Beavers

I became interested in power regenerators because of a tube bias problem I was having with my monoblock amplifiers. Each power tube has a manual bias control, and I constantly found myself having to re-bias the tubes. Their bias would stay stable for an hour or so, then swing up or down depending upon power fluctuations. This was not just an annoyance—it was having damaging effects on both my power tubes and signal tubes. To have expensive NOS tubes go bad after only a few months of use was not acceptable. The first device I tried to rectify the situation was a voltage stabilizer used in hospitals and medical labs, where electronic equipment requires very stable voltage. Though I didn't keep the device, it did show me how much my voltage was fluctuating. When the unit corrected for voltage changes, the adjustment was accompanied by the sound of a noisy electronic motor, and the motor was continuously being activated. I don't think I experienced twenty minutes of listening in which the device did not correct a voltage change. I appreciated the fact that my tubes stayed biased, but I couldn't deal with the noise.

While researching alternatives, I contacted Walter Underwood of Underwood HiFi. Walter recommended the Audiophile APS Pure Power 1050 power regenerator. It had the wattage-handling capability I was looking for, and I really liked the unit's slim design. Walter directed me to some reviews that mentioned improvements in clarity of the sound when using the 1050. This was all to the good, but my main concern was stabilizing my AC power. Based on Walter's recommendation and the great reviews, I ordered a Pure Power 1050.

This device filters the alternating current coming from the wall outlet and provides surge protection. It converts the AC to DC via a rectifier circuit, then uses an inverter circuit to regenerate the DC to clean AC to feed your components. The manufacturer states that "this double conversion technology provides a barrier to problems that might exist on the utility line. No EMI, no RFI, no spikes, no high voltage transients, no damaging surges can reach your components." The APS website addresses another issue worthy of mention—current limiting, which is a concern when you hook up power-hungry amps to a line conditioner. The Pure Power 1050 was tested with a Bryston 9B SST amplifier, which was found to have a peak demand of 3.88 amps. When they connected the amp to the Pure Power 1050 regenerator, it was able to draw 5.6 amps at peak. The device can handle short-term peaks of 18 amps, and very short-term peaks of 36 amps, which is much more than can be supplied from the wall outlet.

The Pure Power 1050 weighs in at a hefty 50 pounds, and is 3.5 inches high by 17 inches wide by 19.4 inches deep. The width and depth make it an iffy proposition for some racks, but it does come with screw-on feet for vertical mounting on the floor. My rack has oversized shelves, so I was able to place it on the top shelf with room to spare. Of the six output receptacles on the unit, I used two for my tube monoblock amplifiers, two for my source components, and one for my tube preamp. When I first turned the unit on, it went through a system check. Everything checked out fine, and I got a green LED "normal mode" indicator light.

First lesson learned: Do not turn on high-powered Class A tube monoblock amplifiers at the same time when they are connected to a power regenerator. The APS unit went into overload mode, with lights flashing and caterwauling alarm bells. There are five LEDs on the front panel that indicate capacity. If none are lit, it means the unit is at less than 10 percent capacity. One green light indicates 10 to 25 percent, two green lights are 25 to 50 percent, three green lights are 50 to 75 percent, four green lights are 75 to 100 percent, and the fifth light is a red light indicating overload, which is where I found myself. I turned off both amps, and the unit eventually quieted down. My next attempt was more successful. I turned on one amplifier and waited, which briefly got me two green LEDs before it went back down to one. Then, after about thirty seconds, the second green LED lit up. At that point, I turned on the second amp. This got three LEDs going, which then went down to two. After everything had been powered up for a few minutes, the unit settled at three LEDs, meaning that my system was using 50 to 75 percent of the capacity of the Pure Power 1050. In the months that I've used the device since then, the number of green LEDs has never risen to four, even when cranking the volume.

In the past, my amplifiers' natural cycle had been to reach a high bias level on startup, then over the course of an hour go to a low level, then back up to correct bias. After that, the bias would go up or down throughout the day. I sometimes had to re-bias the amps on an hourly basis. After I connected the amps to the Pure Power 1050, I crossed my fingers and let the amps warm up for an hour. I then checked the bias meter for each tube. They were high, so I set them to their median levels, then started the music.

The first thing that I noticed was more bass impact. I also heard an increase in clarity—notes sounded more pristine, and I could hear micro-details more easily. The other thing that was immediately apparent was an increase in the ease with which the music flowed. The previously sluggish stream was now a steady-flowing river. Cool! But would the tube bias hold? If the amplifier wasn't hitting on all cylinders, that smooth-flowing river could turn into a choppy sea. I checked the bias meters hourly during that first day, and they never moved. The needles stayed within the bias bubble like they were glued to it. It appeared that I'd found my solution, with the added value of improved sound. Playing my reference CDs and SACDs, I heard many positive changes. I tried each component connected to a wall outlet, then connected to the Pure Power 1050. In every case, the component sounded better when connected to the APS device.

On the second day, a strange thing occurred. The regenerator suddenly went into battery-backup mode, which is usually initiated when there is an AC blackout. I could not imagine what had caused it to respond to blackout conditions when no blackout was occurring. Then I heard the sound of the washing machine. My wife was doing the laundry, and when the washing machine started, the APS regenerator had taken itself off the line.

After several months with the APS regenerator in my system, I am as impressed as can be with what the device can accomplish. I believe that my tube amps, which are serious power gobblers, are an excellent test of the 1050's ability to supply power at peak demand levels. I also hooked up a 7-channel, 300-watt-per-channel solid-state amplifier. This amp only lit up one of the 1050's green LED on startup, and even at high volume, the largest number of LEDs that this beast of an amplifier could generate was two.

Are there any downsides to the Pure Power 1050? If you're hypersensitive to the sound of whisper fans, you might be bothered by the one in this unit. The distant whisper of the spinning blades did register on my senses when I first started using the 1050, but now I don't even hear it unless I focus on the sound. During playback, I never hear it, and compared to the noise of the voltage regulator I first tried, the 1050 is church quiet. I now consider the APS Pure Power 1050 to be an integral part of my audio system, one that I would not want to live without. Highly recommended! John Beavers

Pure Power 1050 power regenerator
Retail: $2495

APS
web address: www.audiophileaps.com