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Romy the Cat wrote:

OK, everything was fine and I might do into the sonic nuances of the PurePower unit. The PurePower drives a lot of switching nose from output. It has the filters but they help only partially. Adding capacitance to the PurePower’s output minimize the noise. In the past I bough specialty for this task some high-frequency-optimized caps and I put them in the game. The PurePower filter has CLCLC filter with 1uF caps. Adding 6uF kills all noise. However, it also softer bass and eats dynamics. Experimenting further I concluded that approximately .5-1uF extra capacitance does OK and it looks like doe not crap dynamics too much. Then I discovered something even more interesting. The PurePower use some ferrite chokes on the cables between the units sections. However, it uses ferrite bagels on both wires suppressing the HF noise across common mode. The differential noise between the hot and neutral wires is not suppressed. I have a lot of ferrite left over from my Tuner/DAC project. http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=7851  http://www.GoodSoundClub.com/TreeItem.aspx?PostID=7949 …so I put some of them on the individual wires – the result was very-very positive – I did not expected even how effective it would be.  So I went to extreme and load the each inch of the free output cable in the unit with a LOT of ferrite suppressors. In fact there is a lot of empty space in the PurePower unit and am planning to order a twice-trice longer cables (between the generator and output filters) and put there insulting amount of ferrite, both in common and deferential position. With what I did load with ferrite the init was very nice with practically no need to add caps to the output. The ferrite kept the “super texture” but took the edge out of it – very nice and gentile effect. I need more ferrite… where this damns cheap Russian surplus suppliers where one you can barter a railway train of ferrite cores for a bottle of vodka…

Socrates once said that non- examined live not worth to live. Well, I ma trying to look “examinatly” at my recent experience with the PurePower regenerator, trying to get out of it what I feel was interesting. Yes, to behave like the “Challenger” and the tendency to blow up is highly unpleasant inclination of the PurePower unit but before it went to flame there was positive and educational experience.

I discovered that further capacitive filtration hurts sound, I observed long time ego in Melquiades section of my site that any capacitors on primary side is infinite evil for dynamics and bass. The PurePower is it looks like have a right balance of carrier frequency filtration and sound. Sure it the PurePower run the sampling rate not a couple dozen kilohertz but a few hundred kilohertz (like most of audio class D amps) then all problems with 50Hz fundamental would go away as the filter would be too far. In case the PurePower however, the out tilter is set fine for whatever the carrier frequency is as it looks like it do fine sonically. It is a very little on the aggressive side of HF range but my late experiments with more ferrite in common and deferential setting indeed help and the it is possible to deal with it and having no negative impact to bass/dynamics as the caps would do.

So, what I would like to try if the damn PurePower ever will work and do not blow? I would like to have a very powerful external high inductance ferrite filter. I can envision it like this: the PurePower is running, producing the audio-capable sinusoid.  All PurePower load is connected to externals powerstrip plugged into PurePower unit. The cable between the PurePower regenerator and powerstrip however is going across a box with very heavy inductive filtration. I can see large 5”-7” diameter ferrite rings with power wires very tightly winded around it, both wires and individual wires. Let to drive non-interfering inductance up and the filter down – we need juts 60Hz fundamental anyhow… Perhaps something like this have already available commercially and juts might be just adopted for use with PurePower? If not then it would be very simple to build the HF suppressor like this. A set of 6-8 large ferrite rings cost around $30, all the rest is just to wind and to fix the cables around them. If my PurePower unit ever will work again I would certainly do something like this.

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