Romy the Cat wrote:

Rakesh, if you feel that theory suggests something then why don’t you discard anything that you hear from anybody and try the Equi=Tech. It is what I would do if I were you.  Equi=Tech extends 30 day trail and payes for shipping. This is very honest way to sell and it gives people like you opportunity do not listen dealer and internet hoodlums but make own judgment. The Cat

Romy the Cat wrote:

So, what the concussion is. It is known that PP2000, as any switching devise, inject a lot of noise into power line from where it sources power. Apparently the PP2000 own filtration can’t handle the noise from the second PP2000. That sucks.

oxric wrote:

Romy, can you tell whether PurePower have identified precisely what made your units to perform as they do and whether that is now a standard feature of their off the shelf units? I am sure many here who might still purchase their PP2000 units would like to know that they can order a PP2000 that performs as well as your present units seem to be doing without having to enter protracted dispute resolution territory with their customer services department.

Lx_ wrote:

Well, this is consistent with the behavior I have. I can hear electrical devices behind the PP, especially those of the switching PS type: computer screen, laptop charger, DSL box, printer, SAT decoder... Good luck finding electronic equipment without one of those these days. Also the PS for the PC I use as digital front-end, which is probably the noisiest of all (not in a good way, as you can imagine). No wonder the PP bleeds through another PP. Yes, that sucks and this is not what I expected from the unit. If you find a way to properly isolate PP output from input-borne AC noise, let us know. APS may be interested too. For the moment I turn off all devices during serious listening sessions (not so hard using power strips with switches).

Rakesh,

The units shipped to Romy in the last 2 months month are identical to every other PurePower 120volt model 2000 shipped in the the last few months.

Romy's units were not "special order" they are "state of the art". They are as close as can be in performance on utility power and on battery. They are as close in performance to each other we can make them. In both cases any differences are negligible.

Rest assured you do not have to wrestle with a customer service department. You can speak directly with the marketing manager or the President. We fully support our warranty - and we have a very generous interpretation of our warranty responsibilities. I would be very happy to supply references if you need more comfort.

Romy the Cat wrote:

Possibly that you are right but it might be something else. My last year unit did inject back to power line a LOT of dirt. I just measured my new fixed unit and I was VERY surprised the it out back to the wall significantly less than older model, In fact what it is full load it outputs back to wall virtually nothing. I made a quick measurement test with how one PP2000 impact another. What the second PP2000 idling it tossed back to the wall huge amount of very nasty shit. As load grow it does it less and less, I use passive load however. When I look at the first unit out what the second one is running I see no evidence on scoop that second unit impact anything.

Romy the Cat wrote:

Sonically however it sound very much like brand new BG caps use. You know that sound when HF feel like coals of 4-5 tweeter and all of them are not time-alighted? The HF are compressed but at the same time infinitely thin, like super sharp balde. I had very same effect from PP2000 3 years back when I exchanged the polarity of hot and neutral at PP2000 input. So, I wonder of possible that Pure Power accidently confused hot and neutral in one of my unit and this give me the ugly BG effect?

Romy the Cat wrote:

BTW, Lxm did you consider to add shunting capacitance to your buttery?

Lx_ wrote:

Another example of cannot-measure-it-but-can-hear-it?

Lx_ wrote:

Anyway, the fact that output noise decreases with load seems an interesting lead to me. Less load means less current through the AC-DC input stage. Why would that generate more noise (unless noise is generated further down the PP, but the input stage seems more likely)? Could you be more specific about what you mean by "huge amounts of nasty shit" -- especially the what rather than the how much?

Lx_ wrote:

Also interesting. I never tried to invert AC input. Do you know if this also inverts PP outputs? If not I can easily try changing input polarity and listen to how it sounds.

Lx_ wrote:

Yes, I even started to look at the CDE parts catalog online but could not find what I was looking for. I'd be glad if you could send additional details about what you have used.

PurePower wrote:

We recommend strongly every PurePower 2000 be supplied from its own dedicated 20 amp isolated ground receptacle. For 2 units it is preferable that each will be separately wired directly back to the main panel, and if possible fed from the opposite split phase bus bar. In all likelihood this strategy will provide more than enough attenuation.

PurePower wrote:

We certainly cannot recommend plugging 2 PurePower devices into the same duplex receptacle in the same circuit since each PurePower 2000 is rated at 20 amps and together represent a potential 40 amp load fed from a single 20 amp circuit.

I am sorry, Richard, but it is irrelevant BS. I have 8Ga line and 20A breaker. If I wish I can reprovision this line for 40A but it is not the subject. I agree that running two PP2000 from same duplex receptacle is not might be a greatest idea but my ENTIRE SYSTEM LOAD sucks 8.9A out of PP2000 and it is in class A, menace the current NEVER go higher than 8.9A. So, what problem I have running even 3 PP2000 from the same receptacle? The point is not my wiring or receptacles but about multiple PP2000 affect each other if they are in close connection proximity. To running my two PP2000 from the same receptacle, regardless what current is serve sis a good way to illustrate, test and find ways to deal with the problem.

Romy the Cat wrote:

A few post above Bill mentioned that he run his PP2000 from AdeptResponse power conditioner.  I am not familiar if AdeptResponse helps to separate one PP2000 effect another. I am not also familiar with AdeptResponse itself. Looking it up it appears that AdeptResponse is nothing but peter power resepticals with shunting caps – a BS in other words. The idea to have shunting caps across AC line is multiple times was discussed by me. I am a big opponent of any shunting capacitor son AC line and transformer primary. If you remember I was experimenting running caps on the PP2000 output and reported that 1.5uF do lower noise and do destroy bass. Whatever capacitance I use in primary do improve measurement and destroy sound, so I never use it. To use the caps BEFORE the PP2000 however might be another animal. I do not remember I was trying it as there was no reason to do it, now there is. I will be experimenting with loading the supply side of PP2000 with caps. I am sure it will reduce the PP2000 crosstalk but will it impact sound negatively – this is the question.

First of all let see what we are dealing with. Below are 3 images.

1)      External power line with one PP2000 loaded at 75% plug in.

2)      The same power line with second PP2000 plugged in

3)      The same power line shunted with 100uF cap with second PP2000 plugged in.

As you see the second PP2000 does crap the power line. It itself is not a big deal and there is absolutely nothing visible on the fist of second PP2000 output. Still, it is visible objective change, and you can see that 100uF cap does cure all problems. I use file Ansar cap 100uP 630V. The cap is silent what I plug in power line with one PP2000 running but as soon I play other one then it begin to have a lot of HF noise, I mean the cap has HF mechanical noise in it. I need to say that I run everything from the single power receptacle with second PP2000 connected to the same power receptacle of to a dedicated power line that run from my main 200A panel on the same “phase”. The result of the nose penetration from one PP2000 to another was identical. I did not run my two PP2000 from different sided of 240V and I have reason to feel that it is not right application.

I need to note that in electricity whatever we see on the scope has mostly very little relation to the actual sound and I invert very little in measurements in electricity as I do not know what to measure.

Now. How it all Sounds.

1)      On the first picture - single New Production PP2000 was use and all system was plagued into it, not all was on however. “On” were juts 2 DACs, PS, transport, preamps, 2 Milqs and bass amp – 75% of full load. The PP2000 was as I said “new production” or the one that was send to me last November and then was fixed. Sorry, in case of Pure Power I do divide the products by vintages as they apparently to sound different. My init has 100.000mF caps added to shunt the internal buttery, there is nothing else is doe to this unit. The sound from this PP2000 is nothing short of spectacular.  I can; not stress enough how good it is, in fact, if it worth anything to you – electricity-wise, I am having the best sound I had. It is not sound as great as during the “super electricity days” but I have a very stable be and very predictable base sound of my electricity. Very very good. If I have the same sound from the rest of my PP2000 unit then I’ll hit the jackpot.

2)      On the second picture the second PP2000 begin to crap to the first one. It sound exactly as I described: too aggressive HF, some upper MF compression and zippy sound. I find it unusable. I do admit that it will be many people out there who will find this zippiness as some kind definition of “quality”. Thos people would be idiots in my book. 

3)      I did not make any listening in the setting as presented at the third picture. I however did very careful listening with second PP2000 off and first PP2000 running with and without 100uf cap BEFORE the unit. To my great displeasure the presence of the caps BEFORE the regenerator was very clearly auditable – I was instantly has much more dry bass and amusical bass with the cap. So, the use of extra cap BEFORE PP2000 I found is very bad idea and not useable to decuple one PP2000 from another.

Saying all of it I have to presume that change brand and quality of the capacitor before PP2000 input might make a difference. I did NOT experiment with this. I personally thought to remove the PP2000 original input filters, to keep no caps AC line. It also might be that the 100uF is too much and something like 10uF would do the decuple duty and will not fuck up Sound. For me it was important to see if conceptually the problem with sound deriving from capacitance on AC side would be transparent through the entire PP2000. It does and this set a lot of restrictions.