Tweakers' Asylum: REVIEW: Pure Power Model 700 Power Conditioner/Surge Protector by Adriel

Model:	Model 700
Category:	Power Conditioner/Surge Protector
Suggested Retail Price:	$1795
Description:	700 watt ac regenerator with battery-backup
Manufacturer URL:	Pure Power

Review by Adriel on July 04, 2010 at 16:01:54
IP Address: 68.7.197.10 Add Your Review
for the Model 700

This is a unit that I went with to power the whole system including amplifiers. I sent off some emails to a few companies asking about noise and such, PS Audio did not reply but PurePower APS worked out a special 30 day trial through one of its dealers.

I stressed the 700 watt capacity at 33%, and it took 3 months to fully break-in. At first, the sound leaned out and got super extended highs like a Tripath amplifier. I swapped power tubes to compensate. But little by little I regained tube magic, until finally what I gained day by day was an improvement over what I had previously.

The unit ran efficiently and cool to the touch.

My occurences of digital fatigue dropped to zero, and since then I have had a fatigue-free system.

Unfortunately the product created a buzz noise in any audio equipment hooked up to it. Whether an amplifier, preamp, dac, or phono. This was audible up close to the speakers, or showed up in the .wav file when recording off a phono.

The most simple test was a cd player and headphone, nothing else. On wall power there was no buzz. Hooked up to the PurePower, there was buzz through the headphones.

At first I thought it was a noise or grounding issue. This led to the $600 Granite Audio Ground Zero, but it did nothing as this was not a ground loop.

PurePower decided over the phone to send an inline-noise device, but over 9 months and it never arrived.

As audiophiles we tend to think of noise, noise, noise. But this was not a noise issue at all.

The buzz coming through the speakers of course, was due to the waveform supplied by the PurePower unit. It was quiet like a buzzing 5U4 rectifier, not really audible at listening position, but there nonetheless.

I can only imagine how much better this would sound with a smoother sine wave form.

With regard to digitizing vinyl albums, I decided to run the phono, firewire ADC converter, and turntable separately on a Monarchy Audio AC 100-watt regenerator. It did not have the problem of buzz, since it is a traditional amplifier design, rather than pwm/digital/class-D. I just had to be careful with regard to its magnetic field, but it archived vinyl just fine without any additional noise.

This is how the vinyl recording sounded, using the buzzing PurePower unit:

PurePower buzz

Sounded like crickets in the background. Totally unacceptable for archiving vinyl.

It is a wonder why this problem is not more widely reported. Perhaps it is swallowed up in the crossover networks of ordinary audiophile systems.

I suppose the next logical step is to try the PS Audio Power Plant Premiere. Since supposedly it is a traditional amplifier design. But I am tired of spending money on audio equipment for now.

Product Weakness:	buzz noise
Product Strengths:	eliminated all fatigue

Associated Equipment for this Review:

Amplifier: Sophia Electric 300B set monoblock
Preamplifier (or None if Integrated): Primaluna Prologue Three
Sources (CDP/Turntable): Audio Note Dackit 2.0, Rega P3
Speakers: Omega Super 8 XRS alnico
Cables/Interconnects: pangea, audioquest
Music Used (Genre/Selections): pop
Room Size (LxWxH): 16 x 12 x 8
Room Comments/Treatments: realtraps widewall + rearwall, auralex ceiling corners
Time Period/Length of Audition: 9 months
Other (Power Conditioner etc.): monarchy ac regenerator
Type of Audition/Review: Product Owner

Amplifier:	Sophia Electric 300B set monoblock
Preamplifier (or None if Integrated):	Primaluna Prologue Three
Sources (CDP/Turntable):	Audio Note Dackit 2.0, Rega P3
Speakers:	Omega Super 8 XRS alnico
Cables/Interconnects:	pangea, audioquest
Music Used (Genre/Selections):	pop
Room Size (LxWxH):	16 x 12 x 8
Room Comments/Treatments:	realtraps widewall + rearwall, auralex ceiling corners
Time Period/Length of Audition:	9 months
Other (Power Conditioner etc.):	monarchy ac regenerator
Type of Audition/Review:	Product Owner