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I would like to offers some thoughts about possible avenues for Pure Power 2000 improvements.  Those thoughts are no specific to the recent November-December events and have broader generic implication. I initially intended to write it to Pure Power owners but I do not see why it might not be brought to public domain, perhaps somebody can contribute something useful or know something about the subject already.

It was observed me during the second year of my PP2000 owning that my unit became more sensitive to incoming electricity. PP2000 still did own duty and the sound was uncontestable better with PP2000 then without it but in the end of my owning of my former PP2000 I did note that sound was changing sometimes, something that I did not see during my first year. I was talking about it before in this thread and I was attributed it to allegation that my buttery was dying, with consequential increase of buttery internal impedance and loosing HF filtration capacity. At this thread I have seen some other people comment about PP2000 residual sensitivity to incoming AC. I do not know if the have properly operating units and being me I can’t accept the testimony of other as evidence and I prefer to base my judgment on my own experience. So, I proposed that as buttery goes week the PP2000 become more sensitive to incoming AC.

I need to make a remark that to evaluate this claim is bit complicated as it the power line might have zillion different factors and we DO NOT KNOW which of them and in which way affect sound. It takes time, listening and interpretation of the heard results to make any judgments. I did do it and I do not know anybody who did it. PurePower make perhaps good sounding regenerator and but they do not use listening tests as evaluation methods, and if they do then I do not much faith in their listening evaluations. There is however a very interesting moment in all of it. The unique topology of Pure Power regenerator might prompt an answer what PP2000 need to be absolutely immune from incoming power on the long run and what can make the PP2000 even better regenerator then it is now. Be advised that that are all speculations but I hope it will encourage Pure Power to look into this as it sounds to me too logical to discard it.

We know that generation and amplification part of PP2000 are very fine but we would like to see if anything might be done better on supply and filtration part. The “fuzziness” noise that PP2000 pick up in AC mode is clearly shall not be there and it is a pure subject of bad PP2000 design, where all PP2000 radioactive elements are piled up on the same VERY tight board in a very dangers proximity. The PurePower worked on the problem and the new PP2011 revision has much less “fuzziness”. I think to get rid of it completely would require a complete change of layout, grounding and insulation – it is a big and costly project and I do not think that PurePower would go there. We are under presumption that the “fuzziness” has no impact to sound. Well, to my ears the PP2011 version with less “fuzziness” sounds significantly betters then PP2008 version with more “fuzziness”. Still, the “fuzziness” is not something that I would like to think too much. What I would like to talk is the PP2000 AC insulation. I told before that PP2000 is unique among all other regenerators and the uniqueness is in PP2000 filtration capacity.

If you do to PS Audio site and pay attention how Paul McGowan sell his newest generation of Power Plants:

http://www.youtube.com/watch?v=iL1Wjeq7eHY

 …then you will see that he constantly stress the fact that his new version has more capacitors. Now they have even newer version then the Premier, they call it P5 and P10 and they have even more caps in DC filtration.  That is right, the more caps they stuff in the regenerators on DC side the better power line decoupling would be. I do not compare Power Plants and PP2000 as there is no even question about the competition, I juts would like point out that in case of  Power Plants Paul McGowan is correct – more caps means better filtration.

If you open up PP2000 then you see practically no large capacitors, in fact there is only 2 very small caps before both DC-DC converters. So, how PP2000 filter the incoming AC noise? This is where the uniqueness of PP2000 takes over. The PP2000 is switching regenerator that works at relatively low frequency 20kHz -30kHz. According to Nyquist–Shannon–Kotelnikov sampling theorem:

http://en.wikipedia.org/wiki/Sampling_theorem

the maximum frequency that might be correctly sampled will not exceed a half of sampling rate.  So, let presume that PP2000 runs at 30kHz sampling rate – that means that PP2000 even theoretically enables to pass anything height then 15kHz. This is the Nyquist Frequency cut off and it is impossible to bypass it. So, wherever Paul McGowan load more and more caps in his linear Power Plant the PP2000 juts do not need it as it does not even know about existence of anything higher then 15kHz. BTW, in view this one of the explanations why PP2000 sounds so much superior then Power Plant. The AC line has a lot of UHF noise. I am taking about 300-1000kHz and about the mHz level. Sure they are way attenuated by Power Plant filters but the problem is that with frequency rises those minute ultra HF pulses pass across all filters like a hot knife passes through butter. The megaHz and gigaHz level is where SS devises are switching and no capacitive filtration will stop them. The PP2000 does not need to stop that noise as PP2000’s input DC-DC converter does not acknowledge the the existence of those frequencies. There is no continues line of wire in the PP2000 and anything above Nyquist Frequency just fundamentally not transparent for a switching unit.

So, in PP2000 we have no UHF noise but we have some crap under 15kHz. The small caps after DC-DC converter can deal with it but they are obviously not enough. The main filtration is take plays with the low inner-impedance of the battery itself. The battery acts as huge capacitor that shunts the sub 15kHz to ground. There is a kink in this wonderful scenario as I wrote before. With battery dies the battery inner impedance rises and it become to me less effective filter. Battery’s impedance is also frequency dependant. At low frequency or at DC the battery resistance is very low but it grows higher with frequency rises. Here is the quote:

http://www.powerstream.com/battery-frequency.htm

“Ultra low frequencies. These are frequencies measured in inverse hours or days. In this regime the battery acts like you would expect it to. At low frequency a battery will act like a current source plus resistance. All of the energy transfer will be due to ion movement through the electrolyte and none will be due to surface charge or capacitive storage.

Medium frequencies, 1kHz to 1 Hz you are dealing in the regime of ion movement. If you are trying to pull a 10 mSec pulse out of a battery you will be accessing surface charge and capacitive storage, but also charge due to charges moving across the electrolyte. By the induced charge theorem a charged particle doesn’t need to move all the way across from one electrode to another to realize this energy, an ion with a charge of one unit will induce a charge on the anode of 1/10 of a unit as it moves 1/10th of the distance from the cathode to the anode. But these ions move slowly compared to the electrons in a wire, and this shows up as an increased resistance. The shorter the pulse and the higher current drawn the more the internal resistance of the cell will show itself.

High frequencies for batteries are above 1kHz. In this regime impedance is a better term than resistance because capacitance and inductance come to play. Many types of batteries are spiral wound, which introduces more inductance than flat plates would, and of course all batteries are capacitors, having parallel plates separated by a distance. If the current is drawn from the battery in a series of short pulses at high frequency strange things can happen. For example you can get crazy oscillations in a feedback situation such as a switching power supply. In these kind of applications a capacitor across the battery lets the battery move into a lower frequency regime .”

Take a look at the very last paragraph. They are taking about feedback situations – that is exactly what we have in PP2000. Take a look what they propose: to shunt the battery with capacitor. A capacitor has opposite impedance curve to battery. Battery has ultra low impedance at low friar and high and high frequency. A capacitor is opposite – it has ultra low impedance ay HF. So, the presumption is that a cap will stabilize the filtration by battery, making PP2000 less sensitive to AC noise as battery gets feebler.

It will be very simple to test the validity of this idea. I was told that PP2000 can work with no battery at all, via some internal switch. So, what is needed to be done is to disengage the battery and to listen Sound, paying attention if the PP2000 performance fluctuates with AC power. If PP2000 will be affected more AC line more without the internal battery then juts adding a capacitance to the battery will cure all possible problems. There is even a space on the PP2000 to put in there a few caps….

Again, and I would like truly stress it, whoever I said above has to do ONLY with a properly operating and properly sounding PP2000. Unless your unit is 2-3 year old and your buttery is dead or dying then it shall not be any notable difference between sound during a day or from a day to day. At least I did not have it for a while. It look s like my new unit does not have it as well but I use it for too short time to be able to accumulate any further observations. What I got my rest PP2000 I bet I will make the shunting capacitor test…. If my plan is correct then the worst thing the I will have will be just a deeper level of PurePowering….

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