Lx, you do not need to convince me that PP2000 has problem or problems. Of cause it is way beyond the sophomoric solutions like lift the ground and AC polarity. No, I did not try the cascading PP2000, I did ask PurePower about it and they were now able to come up with a definitive answer if is it OK to do it. I eventually lost my interest to the cascading as I concluded that it is not due insulation but due to other problems.

My PP2000s did have a problem and I think they did found it, not all of the problems but they are working on it. They are cooperative and they are listening, coincidently when I discover the problem with my PP2000s sound the PurePower owner was at his sabbatical…

The truth is that properly operating PP2000 sounds perfectly fine from buttery or from AC - this is the whole concept. The problem is that I do not think that anybody, including the PurePower people, know why the PP2000 sounds so damn good when it is operating properly. So, I presume they are making some minor changes with the very best intentions and do not realize that they are tossing that proverbial baby while are distilling the water.

There is a joke that I told to PurePower people before the New Year. I love this joke and I always told it to my students. A space shuttle was sending out with join Russian-US mission. It has one Russian cosmonaut and an American monkey. When the shuttle hit the orbit everyone opened own flight plan envelops. The monkey’s envelop said: open solar panels, initiate navigation system, activate cooling system, transmit to Earth the launching data, etc, etc, etc… The cosmonaut’s envelop said: “feed the monkey and do not touch anything”.  It might be funny but in reality I would greatly appreciate if the PP2000 sound was “locked”. It is loose now and PurePower is trying to put it back to the cage. For now, I am without “Romy’s sound” for a while. I have audio friends from Europe who asked me to stop at my place on their way from CES for some listening sessions. This year I turned them down as without my old PP2000 my sound is very much not where it has to be. That is kind of suck and some of them have bought tickets with Boston fly switch….

PurePower wrote:

All of Romy's musings and tests on the relation between the electrical characteristics of PurePower units and his objective and subjective sonic impressions are not applicable to the PurePower 230 volt models. The difference in operating voltage makes a significant difference in electrical performance characteristics even though the technology is essentially identical.

PurePower wrote:

However, it is important to understand that the solution to ground issues will have to be found in the house AC ground wiring, not in the PurePower 2000. The 2000 produces a completely new 230 volt AC sine wave that is absolutely isolated from the utility input power. No sag, surge, transient, distortion or noise present in the utility AC will appear in the PurePower output.

PurePower wrote:

It is worth it to take the time and effort to ensure all ground circuits are properly bonded and correctly made., especially at the service entrance.  Sometimes it is relatively easy to resolve. Using a separate "isolated ground circuit" often is enough, but if the problem is severe, it won't be enough. Some European grounding systems are quite different than North American schemes, but we would be happy to offer some advice and support on that and any other PurePower issues, including dealer support. Just email me.

PurePower wrote:

p.s. All of Romy's musings and tests on the relation between the electrical characteristics of PurePower units and his objective and subjective sonic impressions are not applicable to the PurePower 230 volt models. The difference in operating voltage makes a significant difference in electrical performance characteristics even though the technology is essentially identical.

manisandher wrote:

Well, I beg to differ. There is a HUGE difference in SQ between AC and battery with my new 230V model. The AC is edgy and sharp (pretty much unlistenable) whilst the battery is smooth and harmonically rich.

manisandher wrote:

Meanwhile, I continue to enjoy the PurePower through its battery... though I agree 100% with Romy that this should not be the final solution and certainly not what I paid for.

First of all this post is NOT related to the recent PP2000 problems but it has a border, general view.

The recent LX’s posts made me to think about the PP2000 buttery. He reports that his buttery got way weaken from 2009. I used my older PP2000 from December 2008 and my currant problematic “upgraded” problematic PP2000 used the same battery as I got in PP2000.  On this unit I have a very short run from battery – a few minutes at 75% load. The PP2000 indicator shows the battery discharge 50-60% when then unit shot itself down and my PP2000 never do 20% discharge as LX reports.

I do feel that it is some kind of bug in PP2000 charging/discharging/threshold software. However, there is another interesting moment. Even if to discard the recent PP2000 issuers and to look at the performance of my old good sounding PurePower unit before it was sadly “upgraded” then I would note that in the end my unit was more susceptive to internals AC then it use to be 2 years back. 

I did report this sentient a few month back but then I did not have my playback set and it was rather an impression then a fact. The fully functional and properly sounding PP2000 do sensitive to incoming AC, I commented it years back. The difference between properly functioning PP2000 form one AC and another AC is minor but recognizable. The PP2000 still does what it does and the result from ether type of AC is acceptable but why the quality of incoming AC matter? I was writing about it in past but now I can proposer the following: my observation is that the incoming AC influence grows with buttery got weaken. If a year back I have absolutely invariable performance from my playback, then this year I did detect some bad and good electricity days. It was not where even close to the playback running from the wall and the deviations were very minor but since I am very tuned to recognize those things up I think that my observations are correct. I said “I think” as in 2010 there were a lot of other factors that might offset my judgment but I do count all the things in. Gains, all comments that I am masking now refer to my old pre-upgraded and well-sounding PP2000, prior to the current sonic PP2000 issuers.

So, let look at the proposal that batteries dying might be associated with isolation from AC. It does make sense. In the PP2000 after AC got DC-DC converted to 72VDC there are very small caps to kill all residual noise. The reason is because the batteries itself is a phenomenal huge capacitor that with it’s ultra low DCR and ESR shorts all AC to ground. Then, with time, the PP2000 battery got worn. As battery got worn the DCR and ESR rises and the filtering ability descries, perfectly makes sense…

 The PP2000 uses 6 small 12V sealed Lead-Acid battery with suspended electrolyte. The battery does not say how much A/H it has, the stupid unfortunate practice of the today battery makers.  I anticipate it is about 55 H/A and is similar to the APC RBC10 replacement battery. This battery shall last from 3 to 5 years, I guess, if the chagrins-discarding mechanism is compromised than it might begin to die in 2 years.  So, What I would like to do after the PurePower will fix the ongoing problem is to try to use larger buttery and to see if the I get better (deeper) isolation result. The PP2000 has option to externals buttery and I would like to try it, to see if it affect sound in any way. In my case it will be a bit interesting as I have 3 units. I would like to get from somewhere a truly huge battery, let say 1000H/A. This type of the battery will have equivalent series resistance infinitely low and will so low DCR that it will pump hundreds or perhaps thousands of amperes. If I were be able to connect all my three PP2000 to the same buttery (a big questions to PurePower) then it might be a very interning configuration, not to mention that those big “tank/tracks” batteries live much longer then 2-3 years. Sure, I can make experiment with one unit, I just need to find out if the PP2000 will handle suck a powerful charging. As an alternative I might use bank of 80V/300.000uF caps shunting the buttery to see if it is a right direction.

It would be interesting to experiment with it sometimes in future after my PP2000 will be back to expected operation.

Another thing to think about along with larger batteries for the PP is the charging process, which needs to be "shaped" to make best use of the particular battery or batteries, including maximizing battery life.  Also, if the stock PP2000 uses several batteries in series, then each of those smaller batteries is likely to have a lower Ah rating than a single larger battery would.  All this, along with discharge rates and cycles, would need to be considered in modeling a charging system, and the stock charging unit might not be up to dealing with a larger reservoir.

The one thing I take away from all this so far is that it appears that APS have "found" a way to get hi-fi-friendly AC from a battery or batteries.  In and of itself, this is something unique, as far as I know.  It may be that APS' OEM (listed earlier, up the thread) has a range of DC/AC units that are also sonically acceptable for "running hi-fi off batteries"; I just don't know.  In any case, this would still require a suitable charging system, as well, except in this case the charger would not need to be "silent", nor would it need more than nominal AC "conditoning" of incoming AC.


Paul S

Lx_ wrote:

If the 2000 output is really clean of any noise and only the ground carries whatever comes from the house ground, then how do you explain the tremendous sound improvement that lifting the input ground provides? I find it difficult to not incriminate the 2000, though I am more than willing to get insightful advice.

Romy the Cat wrote:

The recent LX’s posts made me to think about the PP2000 buttery. He reports that his buttery got way weaken from 2009. I used my older PP2000 from December 2008 and my currant problematic “upgraded” problematic PP2000 used the same battery as I got in PP2000.  On this unit I have a very short run from battery – a few minutes at 75% load. The PP2000 indicator shows the battery discharge 50-60% when then unit shot itself down and my PP2000 never do 20% discharge as LX reports.

• This is a 2 year old unit that is always on (to keep the DAC on at all times)
• When the system is operating, PP load is at 38% (system consumes around 600W including PP and external PS not plugged on PP consuming ~25W)
• Battery starts at 100% but almost instantly drops to 56%
• Discharge rate is not linear but not by too much
• Level drops to 0% and stays like this for around 1 minute
• Overall operating time on battery alone is less than 14 minutes
• When plugged back to AC, PP level starts at 61%! (not shown above)

Romy the Cat wrote:

The fully functional and properly sounding PP2000 do sensitive to incoming AC, I commented it years back. The difference between properly functioning PP2000 form one AC and another AC is minor but recognizable.

I do not remember seeing you provide details about this. Could you elaborate on how sound is affected by AC in your system?

Romy the Cat wrote:

The PP2000 still does what it does and the result from ether type of AC is acceptable but why the quality of incoming AC matter? I was writing about it in past but now I can proposer the following: my observation is that the incoming AC influence grows with buttery got weaken. If a year back I have absolutely invariable performance from my playback, then this year I did detect some bad and good electricity days. It was not where even close to the playback running from the wall and the deviations were very minor but since I am very tuned to recognize those things up I think that my observations are correct. I said “I think” as in 2010 there were a lot of other factors that might offset my judgment but I do count all the things in. Gains, all comments that I am masking now refer to my old pre-upgraded and well-sounding PP2000, prior to the current sonic PP2000 issuers.

1. My system has been improved a lot and is way more revealing now
   
2. I am better trained at recognizing differences in SQ
3. PP2000 has become more sensitive to AC

Lx_ wrote:

I do not remember seeing you provide details about this. Could you elaborate on how sound is affected by AC in your system?

Lx, I shut fown my playback in beginning of April, before move, and then got more or less operational playback back in October. I do remember that I mentioned during the last winter that PP2000 changed it way as in January last year I switched my PP2000 to run from utility line – it sounded better then from my dedicated lines, which did not happen before. I do not remember where I posted it, it was too long and my site is too large to look for it. It was nothing alarming, the sound was very good but sometime it was just good and sometime very good. Mind you that behind those “good” I can enumerate very specific and very precise properties of sound. This is not subjective judgment - it was an objective fact.

Later on, in October I wrote in my “New Listening Room” thread.

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=14794

“Today I was thinking all day long what the hell is happening in my room and why the 2” pyramids do the job to subdue HF in my room but still create problem and kill Sound. The ease and spontaneity of Sound the I had just two day back is gone and replaced with labored pressure and not at the high frequency but in upper mid range.  I was thinking listening, changing a lot today in acoustic treatment, even put the large black panels back – nothing worked – the right sound has gone. I played good 5 hours with it and twice fallen from my step ladder – the only think the work properly in my room was gravity… I do not want to give an impression that I love to do all of it too much but I was very pissed as there was some kind of hidden reason WHY it happened and I knew that until I get control over this reason I will not get my Sound in my room. If it was 2 years back then I would blame electricity but now I PP2000 my entire system and I am accustomed that sound does not changed from day to day. “

I remember I have mentioned the similar somewhere else. Honestly, I did not blame the PP2000 at that time as I knew it was running fine, at that time I did not use the new version.  I do not have my old unit (unfortunately), it is upgraded to the new version that has other problems. If I had my old unit then it would be worth to buy a new set of butteries and to compare how the unit insulates from AC compare to the old butteries.  If the new butteries would be better then the measures might be taken to prolong the PP2000 butteries life.

You see, the batteries in PP2000 work in the worst possible condition. Out power never is down and my PP2000, as well as your, was sitting for a year, in my case 2 years, without driving anything.  The acid butteries must work, if they do not discharge anything then they lose capacity. The big and expensive UPS do have built in discharging algorithms,  the small units like PP2000 uselessly do not have it. I am sure that fact that PP2000 looks like a bit screwee does not help ether – my old unit allow to discharge down to 28%, the same “upgraded” unit, with the same battery, do not  discharge more than mid 50%. So, the PurePower has some room for improvement in this department… Still, if the presumption about weakening of batteries and sound is correct then it would be worth to develop a practice one a week to drive the playback from batteries unit PP2000 shout is down. This will train the battery and will make it to live longer. From my collage time I remember that acid batteries need to be discarded no lover then 20%, but it was 25 years ago and the nowadays batteries might be different.

Again, all of it would be applicable to properly operating and sounding PP2000….

Paul S wrote:

Lx_, I can't tell from your post if it was/is clear to you that I suggested lifting only what APS refer to as the "safety ground", as opposed to the "neutral" wire.  In most systems, the neutral is white, and the "ground" is green.  In the USA, this would ba a fourth lug on a 220 service plug/outlet.

Paul S wrote:

My comment on the "dedicated home run (neutral)" means a dedicated, "unbroken" neutral wire running continuously from the PP alone, clear back to the main neutral/ground bus, in the main service box.  If indeed noise on the neutral wire is a problem, then this represents one's best chance to quell such systemic ground noise.  If any problems getting through the PP arrive via the "hot" wire(s), then no amount of messing with wire configuration will stop the noise; only unplugging the thing would do it.

Lx_ wrote:

Also Romy suggests that even its old, well-performing PP was still sensitive to input AC (I have yet to read his post about this). So it seems that the PP is indeed not completely immune to incoming AC noise, and any solution to lower that sensitivity would be more than welcome.

Romy the Cat wrote:

Lx_ wrote: Also Romy suggests that even its old, well-performing PP was still sensitive to input AC (I have yet to read his post about this). So it seems that the PP is indeed not completely immune to incoming AC noise, and any solution to lower that sensitivity would be more than welcome.  It was NOT what I said and it was not want I meant to say.

Romy the Cat wrote:

The fully functional and properly sounding PP2000 do sensitive to incoming AC, I commented it years back.

PurePower wrote:

I'm happy that I found out about LX_'s problem in France with his PurePower 2000 230 volt model. I'm sorry we had to hear about it on Romy's forum so long after the fact because his problems would have been solved long ago. Unfortunately his dealer went out of business without passing on any information to us - and LX_'s name had never been registered in our customer database - so this is our first contact with him. Now that we are in touch he can expect a quick resolution to the problem - whatever it turns out to be - and his audio system will get the benefits of pure power isolated from utility problems - whether his PurePower is operating on battery or on utility.

• "AC": normal PP operation, running from utility AC
• "grounded battery": I can switch to battery mode to disconnect incoming AC hot and neutral, but leaving utility ground connected
• "pure battery": I can unplug the PP from mains to disconnect incoming AC completely, including ground
  

• PP output is not completely isolated from input; this is true for ground as well as hot/neutral
• Either PP lets input AC noise through, or there is a problem with the battery charging circuit generating noise on the output, or something entirely different. But noise gets through when not on battery. APS should be able to fix this.
  
• Ground noise is an issue for which I have no acceptable solution at the moment. I think APS will not work on this, they say PP will not solve ground issues. Lifting ground is OK for a simple test but I do not want to operate like this. I will have to try using a filter on incoming AC. Otherwise I will have to live with whatever appliance noise there is.

LX wrote:
"...Lifting ground is OK for a simple test but I do not want to operate like this..."

With ground lifted, why not simply run a single-conductor cable from the PP's system ground (or chassis) so that it makes electrical contact with one of the water pipes in your building?

This for me is standard procedure.

jd*

Lx_ wrote:

The second sentence is my own conclusion. It was not my intention to imply that it is yours, sorry for the misunderstanding this may have caused. We both agree that PP can be sensitive to incoming AC. The context and circumstances are different though and we still do not know what can cause this behavior.

Lx_ wrote:

What can we infer from all this? PP output is not completely isolated from input; this is true for ground as well as hot/neutral Either PP lets input AC noise through, or there is a problem with the battery charging circuit generating noise on the output, or something entirely different. But noise gets through when not on battery. APS should be able to fix this. Ground noise is an issue for which I have no acceptable solution at the moment. I think APS will not work on this, they say PP will not solve ground issues. Lifting ground is OK for a simple test but I do not want to operate like this. I will have to try using a filter on incoming AC. Otherwise I will have to live with whatever appliance noise there is.

Regarding your case. I do not know if your problem is with your grounding pattern or with some kind of defect you have in PP2000. Your staggering with your PC PS I find irrelevant as whatever damage it inflict it would be damage dams, the  damage from AC fluctuates dally and hourly.

You can easily test it if the problems you have are not ground problems. Got to a home improvement stare and buy a couple dozens of cheater plugs. Plug ALL of your complements into the cheater plugs, assuring that none of them will read the PP2000/AC ground. Alternately your can plug all of your equipment into a power strip and then the power strip via the cheater plug to the PP2000.  Be advised that it might be a bit tricky and you need absolutely assured that there is no pass from your equipment ground to PP2000 ground. If you have your PC plugged to PP2000 and PC use a monitor, of powered KVM switch or any PC peripherals plugged into AC and do not have ground lifted then your experiment will be wordless (and you will have some ground loops in addition) . so, for the sake of simplicity you might use the only few components the do sound form you like (CD-DAC-Pre-Power amps) – it would be easy to control them. If your system is not balanced (like mine) then run a R-meter between AC ground and ground terminal of your RCA jacks - you must NOT have a direct path- it shall be kOhms or mOhms.  Now, your playback ground is completely lifted from AC ground. You might have a lot of voltage between AC ground and your playback ground. Do not worry about it . There is an important this in this case – do NOT touch with your hands  PP2000 chassis and your system ground at the same time, in fact keep the PP2000 aside from playback to eliminate any accidental contacts between them.

What you have now is a perfect test environment to test of your ground is dirty. Listed the result you what you have. Then find a single point of your system (in my care it is preamp grout) and run a fat high ga. cable (I run #2) from this single point to your AC ground, before the PP2000. Compare the result. Then make your own ground (plumbing pipes, gas lines, own dedicated rod in yard). Run your fat high ga. Cable to this ground and observe the results. If your playback is properly organized and built then you shall not have any sonic differences between your own “clean ground” and the completely lifted ground.  You might have some difference when you use the AC ground but it will be no huge. I personally do not believe that your appliances might inflict so much harm via ground - they shall not do it. and if you have problem with sound that you feel coming from your appliances then the problems are not coming to you via ground.

In my personal side I would note that what I have PP2000 properly operated then I would use the “lifted”, or “own ground” approaches or to plug everything in PP2000 as use it as is – all of the methods produce fine results. There was “some” but in either configuration it was perfectly usable. As now, looking back, I might say that this I those “differences” did change in the end of my properly operating PP2000 tenure. I attribute it now to the battery dyeing but as I told before this is just a hypothesis.

PurePower wrote:

p.s. Do not follow the advice of creating a new ground for the audio system alone. Multiple grounds can cause very dangerous, even lethal, unintended consequences.

Actually it is incorrect. I do understand why a manufacture would take this position. If I were a manufacture I would threaten that I’ll void warranty if ground is lifted. But if I were a manufacture I would also electrocute any user who is republican, so my behavioral pattern is not the best judgment.

In reality to have a own dedicated, properly made ground for audio system is not only not dangers but very-very desirable. The ground that come from AC lime is dangers not the own dedicated ground. The ground as it usually made in residential houses is not so good. The power enters into the main destitution box and right here is it grounded to usually water pipes. If you have a short 200 feet always that the in-rash of currant must negotiate the impedance between the water pipes and the location of the short – and this is let say 200 feet of 12ga cable. This copper 200 feet run will resistance over 1.5R and if it twin-triple cable then 2-3 time higher. This is VERY bad ground to begin with, not to mention that all utility devises in the house defecate to the same ground wire. If a person live in apartment complex then the path even further. The point is that all ground polluters might be located between the playback and the true ground – not a good satiation.

If one has own dedicate properly made ground for audio system then the resistance of this ground is very-very low. I have 10 feet cable with 0.012R resistance and it is MUCH shorter path to any short or noise. There are people I know they install the ultra-low impedance grounds. They charge a lot of money and the give some insane numbers, like 0,00001R. I do not have equipment to measure my ground impedance. I have 15’ rod that I drove to the ground fertilized with alkalizes. So it shall not be bad but not near as close as it might be.

The point is that it is very simple to have your own ground much better than the wall’s ground. The problem with manufactures is the person who does it might be a Moron and whatever ground he/she did might be wrong ground. Manufactures have no control over it and therefore they understandably insist to use the dealt ground as it required by code. Still, it is not about the quality of ground but about management of liability. Understandable but not the final judgment from sonic  and system design perspective.