The Pure Power APS 2000


I felt original review done last week were deemed too prematurely terminated, due to an misunderstanding of the deadlines involved. I can understand, this is a near monumental PLC product today, or hot of the month, so to speak. Many in the industry are clamouring to have a go at it, the line is long, and nobody wants to be last. The product came to me brand new, with only a few hours clocked with batteries half charged.

The other possible reasons why the Pure Power got a less than glowing review are:

1) According to one of our readers, my crappy power cords used.
2) The unit has yet to break in when the review period had to be concluded.
3) Setting up issues.
4) My use of contact adaptors between US outputs and British 13A plugs.

Mr Eng, the local distributor and Bob Rapaport of Pure Power has contacted me since with some tips that might actually fix the high frequency issues I was hearing from the Pure Power APS 2000. Mr Eng have also graciously allowed me to keep the unit for a few more days for further investigations.

Many years ago in Hong Kong, I heard audiophiles there(mostly Marantz CDP owners) were clamouring to buy device to step down their wall voltage supply from 240V to 230V. Reason being that it sound better. So when Mr Eng suggested me that the Pure Power APS 2000 can be internally adjusted to output at 230V, as some systems may benefit from it. I jumped at the chance. As the adjustment is done internally, users would be advised to ask Mr Eng to perform this critical work. I took the chance to marvel at the internals of the unit, which I can only say that the internal build quality is even better that the externals. This is state of the art stuff.

Adjust to constant output of 230V.

Now voltage outputting at 230V, all further review experience would be based on this setting. The sound took on a slightly different perspective this time. The highs are first thing I looked out for and was not disappointed to find that the raggedness experienced earlier was no more an issue. High hats sound a lot more natural now with good timbre, texture and extension. The elements of attack, sustain and decay on many instruments like the earlier mentioned high hats and piano was impressively real. With the more natural highs, the vocals also took on a more open quality, less restricted you might say. Bass slam was well maintained, and the elastic bass quality heard before was still very well present. Towards the end of the review time last night, the highs started taking on a slightly mellower quality too, which I like, but also indicating the unit was just starting to break in.

Bob Rapaport suggested that I do an A/B test myself to see if the output from the batteries matched the output from regenerated power as I had earlier reported about the minor saw tooth pattern within the sine wave, when magnified via an oscilloscope, which may have contributed to the ragged highs I was experiencing earlier. Bob explained that battery power is the purest form of power and will certainly have no saw tooth pattern when measured, compared to PCM regenerated power. This very simple test that involves switching "Off" wall A/C supply to the Pure Power APS 2000, so it'll automatically switch to output from battery power. It lasted a good 25 minutes or so when battery charge level drop to 25% or so, then I switch "On" power supply from wall again. Bob says most people would not be able to tell the difference in A/B double blind test. I agree. But subjectively, I did heard a very, very, minute difference, when playing a flute solo during a quiet music passage, the flute just appears to be a little bit sharper outlined within the sound stage with A/C supply compared to battery supply.

Just don't challenge me to the A/B double blind test though.

Bob also pointed out that my recommendation to power sources and pre amps via a third party passive filter would result in diminished dynamic slam and transient response. Yes, fully agreed with Bob on this with the unit set to 230V output. When set up to power my sources and pre amp via my Isotek Sigmas which still takes power from the Pure Power APS together with my Pass mono blocks feeding direct via the Pure Power APS, I found the presentation to be lush, smoother, airier still, yet have just a touch more body and when listening to classical music, gave a more mid hall or row M seat presentation. The trade off, was little less imeadiate transparency, bass slam and transient response compromised.

Running the whole system directly off the Pure Power APS 2000 gave an overall closer, more immediate and up front presentation, great dynamic slam and transient response, plus details a plenty. However I found that for long term listening pleasure, it was a just a little overwhelming, after what was initially seemed to be very impressive. I can see rockers and other hard charging music listeners loving the unfiltered sound more. As they say your music dictates your sound.

For the moment, the Pure Power APS 2000 is the most full featured PLC in market. Factor in the very neutral, highly focus and dynamic sound, not to mention the big, big sound stage projection(beyond my room walls), it's probably also one of the best PLC at the RM$10K plus price range. I would certainly say that it would be very foolish to buy a PLC within the price range or higher without auditioning the Pure Power APS 2000 first! As you've read from my experience, the unit offers all the protection and it's very adjustable too.

My usual caveat for recommending PLC still stands, due to the following conditions:

1) Every system places different demands on PLCs.
2) Every area's power supply off the wall is not the same quality. Some will hear more improvement than other's, only because the power supply from the wall was poorer quality to start with. These people will certainly benefit more from PLCs.
3) Every person's musical taste and hi fi journey is different, hence the expectation is different too.
YOUR MILEAGE MAY VARIES!

Finally, a little technical observation. I very much admire the efforts taken by Pure Power to take the 240V A/C supply from wall, converts it to 72V D/C partially stored in batteries then amplifies the D/C back to 230V or 240V of your choice. One look inside shows the amount of design commitment to make this the best PLC ever. However, I am a little puzzled at the output stage, where all the outlets are daisy chained and un isolated, un filtered. My personal concern is this will only allow the digital source to bleed back noise via the power cables only to be transferred to all the other equipment connect to the other outlets within the daisy chain. Perhaps Pure Power can enlighten their thoughts on this concern in our desirable thoughts section?


Pure Power is sold by Sound Precision, contact Mr Eng, tel:012 2353763

16 comments:

Bob Rapoport said...

Hi Panzer, Bob here from PurePower. You are very good. The question at the end of your recent post about isolation and filtering of the receptacles is a good one. We hear it from time to time from people who have been charmed by the snakeoil salesman into believing a problem exists when in fact, its just more bullshit to baffle and confuse you.

We've heard the theory about how noise from a digital source can be transmitted back up the AC power cord and damage the listening experience for the component plugged in next door. Have you ever heard how loud the 50hz carrier tone is? Its loud. If you plug your speaker directly into the wall outlet, you will hear it.

Its 1000 times louder than any noise coming the other way from the CD player, it would be impossible to hear even if we could prove it existed, which we cant and nobody else can either. Its just a theory.

As we have pointed out previously, we dont use filters because they crush dynamics. Even small ones on the receptacles deminish the dynamics and we just dont like doing that, especially since the idea behind our product was to prove that most audiophiles have not heard their systems because their amplifiers have been robbed of voltage and current just when they need it most, dynamic peaks.
I think thats what you experienced when you said it was a little overwhelming. You have never heard how loud your amp can play because its dynamcics have been crushed up till now, either by a conventional PLC or the mains power sagging.

I hear that you want to compare the Torus against PurePower. The Torus is like all the other PLC's--just another power strip in a box. All it can do is filter noise and protect against surge. In a double blind AB test, I can show you a decent $99 power strip that will do the same thing...why waste all that money on an expensive chassis and a transformer that will totally crush the dynamic range of any system it is connected too?

We believe a fully isolated battery is the benchmark for perfect power.
We attempt to match that. Nothing else even comes close to the science behind what we are doing so be careful about the claims made by the hucksters trying to take your money. The hifi business is famous for selling voodoo instead of real solutions. I can alter the sound of a system, any system, in your room by simply moving the speakers 1 inch in any direction or by adding acoustic absorbtion materials to the walls. The room acoustics have a much more profound effect than anything else on what you hear.

Panzer said...

Bob,

A big warm wellcome and thanks for dropping by our blog.

My final technical question is a concern that will require a competent answer. I understand it that it's just a theory and was hoping that someone with authority on the subject matter could shed some light on to.

This is fact that I found almost if not all powerstrips and conditioners(prior to Pure Power) have them individual or duplex output filters.

Yes, Bob there will be a shoot out between the Pure Power and the Torus Power. On paper at least, both are closely spec for ratings and capacity. However, price wise, the Torus Power is another rung up the ladder.

I agree that speaker to room interaction is the most profound subject when it comes to setting up an hi end audio system.

Cheers!

HAFIZ said...

bob,

thanks for the explanations

I,for one ,am very keen to try it out...

currently,I too have come to the conclusion that transformer based PLCS are not neutral enought,and certainly add a lot to the sound of most system.........

chin said...

Hi Bob,

Glad to haer your explanation
I believe the better way to provide a better power source must not forget the primary filter and with good PFC. 2 stages of conditioning as APS does can create harmonics easily but oterside provide easier of line filtering handling.

chin said...

hello

jeremy said...

Power regenarations,based on my long experience of PS audio PP,HAS BEEN THE UNDISPUTED KING when cleaning the source and preamp power supply...

i have yet to try -no experience with pure power here-a PLs that my WAVAC monobocks like...could this pure POWER APS BE THE ONE?Iplan to find out soon too

hifikaki said...

Dear Bob,

Plugging a speaker directly into the wall as per your suggestion will not only damage the drivers, but may also give the person a deadly electric shock, with the 240V AC used here. But I do get the point your tried to convey.

Though I don't think that any of our readers will take this suggestion literally, I think it is just prudent to point it out.

Bob Rapoport said...

Hi Panzer,

I spoke to Richard and Damian at PurePower after sending my last post. As the sales and marketing hack, my answers are not always what the engineering dept might have said.

They told me that the kind of noise made by CD players is from their switch mode power supplies. As such, its not really considered noise, its considered distortion, the kind that causes flat-topping of the sinewave. A noise filter would not get rid of that so filtering the recepatcles for it would do nothing. It would show up on our sinewave and we dont see it in our measurements.

My argument that the audio level of the actual sinewave prevents anything that might be coming back up the line, either noise or distortion, from being audible is logical and easy to understand, however, as one of your readers correctly points out, plugging a woofer into the wall outlet is dangerous! Please dont do that.
Trust me, its loud. :) I was just trying to illustrate a point about how a theory about digital noise can be mis-understood.

When it comes to questions about power quality and management, I trust the guys at PurePower. They have the background and understanding to dispel myths in a way thats refreshingly free of hype.

Thanks to all for your kind words and thoughts.

Bob

Richard at PurePower said...

Hi Panzer

Nice to see some knowledgeable audio bloggers concerned about my favorite topic. Power Quality is a complex, boring to most, unheard of by the rest, technical backwater - but boy does it make a difference in the world of a/v performance.

I'd be happy to weigh in on any aspect - but since there was some discussion of isolated recptacles and cross contamination let me add a note about isolation.

There is a great deal of confusion about the term “isolated receptacle”. The term is often misused or misapplied.

An isolated outlet is better described as an “isolated ground” outlet. Its purpose is not to provide clean AC power – an isolated ground receptacle has no effect on AC power quality. Its purpose is to make sure the safety ground wire has the best direct connection to the supply ground at the service entrance. This is critical to prevent unwanted currents or noise from being carried between the common and ground wires. Ideally there is zero potential between them, and therefore no unwanted signal, but bad connections can create an opportunity for “common mode noise” to exist.

Expensive isolation transformers can be used to create a new “clean” ground at the point of use and this will fix a common mode noise problem – but at a high cost and a risk of dampening audio system dynamics. It is better, and cheaper, to run new, uninterrupted wiring from the service entrance to a single “isolated ground” receptacle. This simple step will almost always be effective at cleaning up common mode noise that can cause hum.


All AC circuits in a single residence are connected together, and a power problem that exists at one outlet will be experienced at all outlets served by the same distribution transformer. This often means you are sharing power problems with several of your neighbors. The only way to truly isolate one receptacle from another is to provide separate power sources for them. This can be done by individual isolation transformers, or by separate AC Regenerators.

When you see the term “isolated outlets” in receptacles in the same enclosure or on the same power bar you should take the term with a grain of salt. Many power conditioners have an added low pass filter – basically a small coil and capacitor – attached to each receptacle. The theory is that this will filter high frequency noise generated by a device plugged into one receptacle and prevent “cross contamination” to other devices.

These inexpensive filters may have some efficacy, but there are 10 different “power gremlins” that can reduce AC power quality, and a filter can only affect 1 of the 10, so perhaps “1/10 isolated receptacle” might be a better descriptor. If you plugged your amplifier into one outlet, and a light dimmer switch into the other, some of the high frequency noise from the dimmer switch could be attenuated by the filter. If you own a CD player or preamp that makes noise like a dimmer switch, it could likewise attenuate that noise. (My advice to all audiophiles is to not let a dimmer switch come anywhere near your house, and if you bought a piece of high quality audio gear that radiates noise like a dimmer switch, send it back.)

There are two flaws in the filter plan. 1: most audio system component power supplies either do not radiate such noise into the AC line, or they are so small a contributor as to be negligible. 2: The distortion they do tend to generate is harmonic distortion. This distortion is completely unaffected by a low pass filter.

PurePower’s engineers considered adding low pass filters to our output receptacles, but discarded the idea. We believe it is just as likely for the filters to reduce current flow and diminish sonic performance as it is to remove harmful high frequency noise. We think they are of small benefit – other than to use as a marketing point.

We do continually test customer systems to look for examples of cross contamination. So far we have not detected any, but we will keep an open mind.

sityong said...

Hi there, we are Purepower Malaysia dealer:
We provide free home demo in Klang Valley 7 days a week including late evening, Sat, Sunday and Public Holiday.

Regards,
Sound Precision Sdn Bhd
Contact: Mr Eng 012-2353763
Mr Chan 019-3825937

Panzer said...

Richard,

Many thanks for the enlighthening post. I read and re-read with great interest.

Guys, this product is backed up by people who knows their stuff. Not hot air or marketing B/S!

If you're in the market for a RM$10K+ audio or AV power solution, you'd really have to shortlist the Pure Power for an audition.

Panzer said...

Hi!

Heard the Pure Power 1050 powering up an pretty nicely matched system today, and as I suspected, the demo was done using the Pure Power 1050 to power the power amp, while the CD transport, DAC and Pre amp was power via a Shunyata Hydra 4, it self plugged in to an out put of the Pure Power!

The sound was dynamic, detailed, yet had a certain sultriness reproducing female vocal, Tsai Chin, if you had to ask!

samir said...

Hi,
Pure power is a great product and i am considering getting one myself... was checking out the 1050 model at a friends place and noted a tiny sparking sound coming from the unit itself once its on...it wasnt humming, but more like a sparking/arcing kind of sound. My friend said he had conferred with the company and that he had been informed, that this is a natural sound and it can get louder or softer depending on how bad the mains supply really is.

Is this true, with this soft sparking sound come from all units, could it be a manufacturing defect or a loose component within?

Will look forward from any other PP owners who have experienced such a sound or a lack of the same.

Thanks,
Samir.

Panzer said...

Samir,

I can confirm the review unit had a similar sound whilst in operation. However the intensity of the said sound would appear and dissapear too, depending on music load, or perhaps when power supply from wall is varying in quality.

I can only specualte it's part of normal operating condition.

samir said...

Hi 'Panzer',
Many thanks for taking time out to reply. On further investigation, I found that if one put the pure power on 'test', the same crackling sound is produced for the 10 seconds or so while the test lasts. So even my guess is that this is probabaly a function rather than a abnormality within the unit.

Further, we opened my friend's unit, to adjust the voltage from 240 volt to 230 volt. He had ordered it with 240 volts, but later decided to make it 230 volts...the operation itself was easy enough, but it was a delght to see the inside of the pure power...the components were high quality, the arrangement was nice and one could make out that for the money, its not just an empty box , but holds a lot of electronics. This is the bright side.

I was slightly taken aback, when i saw the insides of the metal body itself... it was rusting.. both the bottom plate as well as the top plate. Its thick sheet metal and nicely powder coated in the outside, but inside, it was a thin layer of grey paint, and was full of rust. I can confirm that the unit is only a year old, and while weather can be categorized as humid, the unit itself is in a closed air conditioned room. I am surprised, that PURE POWER after having taken so much care in everything, did not think of powder coating the insides of the box, or atleast using better metal sheets that would reject rusting... it as not slight rust but that kind of rust, that grows and grows.

Sound wise..utility wise, i would give pure power 10 on 10... and leaving aside the disappointing paint job on the inside, which actually will not make a diff on the sound, but will overal affect the pure power unit itself in time to come, i have absolutely no complaints.

The fact, that this unit will improve your sound is completely true.. it is amazing.

One simply cannot compare a product like pure power to other products as power strips and normal UPS and such stuff.. there is absolutely no comparison.

And, installing a pure power is a better solution than getting some expensive power cables.

Just thought i would add in my opinions while i am at it.

best wishes,
samir.

Panzer said...

Samir,

I am glad you like the Pure Power, I personally find it a top contender for the PLC stakes! Though it wasn't the best fit in the context my system, I am very sure others will find it great, if not the best in their system.

As I have said evaluating PLCs are very difficult as it is very re- active to the system that it's powering and the quality of juice that it's getting from wall, and the last issue can vary a lot from area to area.

As for the inner chassis rsuting issue, Pure Power uses computer like inner frame chassis, which is rather common on industrial grade products. I think most of the budget went in the parts that give the sound, hence that impressive looking internals, rusting chassis aside.

Don't worry about it!