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Romy the Cat wrote:

I got my last PP2000, after the repair was done. My second new unit works since I got it repaired; it runs the whole playback, sounding very well and my attempts to add a second PP2000 led, as I described to worsening of sound. In the very deep core of my soul I was hoping that the second PP2000 that I was trying to add was in some way broken. It sounded fine itself but running along with my main unit it was not usable sonically. I thought that there is some other unknown defect in this second unit that made it happens. Two days ago I got the last third unit and it behave identically when it added to the first unit – so it was no fault of the specific wrongly assumed to be “broken” PP2000 but rather the characteristic of the topology, or at least the given implementation of the topology. Ok, I have now 3 fine working PP2000 and I can use only one unit, that sucks. I truly would like to have my power class A DSET amps to be driven from separate PP2000 and my class A/B ULF channel amp along with the front end to be driver from another PP2000. I have agreed with a ridicules idea to use my third PP2000 in my office as UPS for my computers. Still I need to learn how to employ two PP2000 for audio. The whole point to have two PP2000 to sound worse than one PP2000 defeats the purpose to employ the second PP2000. My objective is very simple: I have the whole playback running from one PP2000 and then to have another PP2000 plugged idle in the same line, while doing it I shall not have any degradation of sound in first unit. I do not have this result now. As soon I plug second PP2000 into the wall I got a lot of zippy brightness in the first unit. I am not willing to do any capacitive filtration before first PP2000. This is the condition of the task and I do not have a solution for now.

So, the sound was clearly degraded in the same way but the unit outputted less noise back to power line Interesting. I took an electric heater with adjustable power and was sliding the load to the second PP2000. The variation of the load made the second PP2000 to output very different amount of noise to power line (more load = less noise) but what was surprising the amount of HF harshness was fluctuating very little. I got to be something else I figured.

I asked myself if it is possible that two PP2000 mutually affect each other by magnetic of radio filed?  My two PP2000 are sitting parallel to each other at very low high proximity:

http://www.goodsoundclub.com/Site_Images/InsulationTransformer_3KW.JPG

So, I pull one of the second PP2000 out of the shelf and placed it good 6 feet away. Halleluiah! The HF harshness dropped very substantially. It was not gone but I would say 80% of it gone!!!! OK, I said, it is in the power cable that was running from the second PP2000 to the power receptacle behind the first one. I took as much large ferrite as I had in home and winded with power cable a huge choke, addling in the free space of the cable over 20 like HF common mode chokes. The noise dropped practically to nothing. It is still very slightly recognizable but it is not as near offensive as it use to be, at least it is how it sound with TODAY electricity.

OK, this is VERY good result, the PP2000 turned to be “radioactive” but this is workable. It is ironic that I discovered it in the 25 anniversary of Chernobyl catastrophe! The discovery made me VERY happy as not I can construct some kind of shield between the two PP2000. It also gives me another VERY fruitful direction to think. The PP2000 power cord is 6 feet and it sits right next to the many power cord that leads to the clean output power receptacles and cables that do to the equipment. So, the PP2000 power cord is “dirty” with the PP2000 returned noise and the PP2000 power cord must go away from clean output power cords. Since it is not possible in my layout then my PP2000 incoming power cords must be shielded.

BYW, this also would explain why Bill does not bitch about the PP2000 effect each other in his situation as his has his 3 unit sitting in 3 different location of his room.

Wow, this, if it confirms itself in the next few days, will be a major breakthrough in my use of the PP2000.

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