The sad thing is that Jim is actually smart and knowledgeable. But the lure of that paycheck can be an overwhelming temptation.
That was what I took from it. Now of course, flat topping in domestic mains loses you peak voltage, so you do get that back for your 5k...
So you are putting lots more harmonics in on the primary and this reduces harmonics on the secondary how? when the diodes conduct the caps take a biiiig glug-o-current (tm), which is a function of the impedance of the circuit not the waveform? What am I being dim and missing?
Analyze the simplest case first: perfect (0.000% THD) sinusoidal Thevenin source driving the primary. Plot the current waveform (ooh spiky!) and take its Fourier spectrum. Many harmonics. Is this a surprise?
Second, drive the primary with a somewhat-flattened-top Thevenin source. Plot the current waveform (not quite so spiky) and take its Fourier spectrum. Reduced harmonics.
I think what Mark is saying is that the flat top rounds off the current spike through the rectifier diode.
With the round top, when the diode opens, the voltage continues to rise and increases the current pulse beyond what it would be with a flat top.
Sharper pulse = more harmonics?
But sim is good, let us know.
Jan
With the round top, when the diode opens, the voltage continues to rise and increases the current pulse beyond what it would be with a flat top.
Sharper pulse = more harmonics?
But sim is good, let us know.
Jan
Are you sure the gold is still there? Copper diffuses through gold and the surface gets rather quickly tarnished with oxides and/or sulphites. A perfect contact storm.
The attached .wav file (inside a zip archive) may help. It's a 230V, 50Hz sinewave with flattened top. Amplitude adjusted so VRMS is still 230V. LTSPICE total harmonic distortion (@ 1usec transient stepsize) is 5%.
To use it, you include a spice directive
- Vname node+ node- wavefile=FILENAME.wav
_
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Fascinating! Jim Austin, the first guy to insult me in print, over some tweak mentioned on the internet, is now criticized by the people here. I think he has a PhD in physics or something. I'm surprised that he has kept an open mind about reviewing an accessory, but pleasantly surprised.
For the record, the very idea of making an amp to clean up the power supply line was first mentioned by Enid Lumley, decades ago. People who tried the first PS really liked it at first, and it superseded early attempts to do it passively with isolation transformers/filters, or with Bybee devices, about 10-15 years ago. The original PS design was problematic, (I have one here in my lab somewhere) because they could be unreliable. They also had limited peak current capability that limited their universality. Over the last decade or so, Bybee hired a former HP engineer to design an active alternative to the PS approach with some success, primarily with much larger peak current reserves. Some of these designs have been sold to other manufacturers, and recently, Jack Bybee went toward an all passive design that works as well or better than his previous active designs. I use one, so does Jack Bybee, and the former HP engineer as well. This conditioner uses a quantum mechanical approach, primarily, but unfortunately was discontinued because of the amount of effort involved to make it, (and Jack is now 86 or so, and he has to make each one) so it is not available anymore for general purchase. That's what I know up to now.
I think that the PS audio design is a good attempt at improving the line 'purity' and that it should be considered a viable product.
For the record, the very idea of making an amp to clean up the power supply line was first mentioned by Enid Lumley, decades ago. People who tried the first PS really liked it at first, and it superseded early attempts to do it passively with isolation transformers/filters, or with Bybee devices, about 10-15 years ago. The original PS design was problematic, (I have one here in my lab somewhere) because they could be unreliable. They also had limited peak current capability that limited their universality. Over the last decade or so, Bybee hired a former HP engineer to design an active alternative to the PS approach with some success, primarily with much larger peak current reserves. Some of these designs have been sold to other manufacturers, and recently, Jack Bybee went toward an all passive design that works as well or better than his previous active designs. I use one, so does Jack Bybee, and the former HP engineer as well. This conditioner uses a quantum mechanical approach, primarily, but unfortunately was discontinued because of the amount of effort involved to make it, (and Jack is now 86 or so, and he has to make each one) so it is not available anymore for general purchase. That's what I know up to now.
I think that the PS audio design is a good attempt at improving the line 'purity' and that it should be considered a viable product.
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Shhhhhhhh..... why bring such details into it?! (Plus, IIRC, direct adhesion of Au to Cu isn't so great either, so you want that interfacial layer)
Heavy gold plating stays OK, due to lack of pinholes. However, I used to have some RCA connectors that looked like they had spots all over them, just sitting in a drawer for a few years, so I know what to look for. Actually, most people use a non-magnetic form of nickel interface with modern RCA connectors (the good ones).
First attachment, 230V /50Hz wall outlet. Waveform with typical (in my area) flat top.
Second attachment, unloaded secondary of a 500VA isolation transformer connected to the same outlet at the same time.
Every transformer I have checked adds some more flat toping (noticed by increased number of harmonic peaks).
George
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I was ready to buy one after seeing the waveforms in #82900 but I balked at the price tag. $1000? I'll buy. $5000? No thank you.
Incidentally PS Audio has a US Patent on a power line regenerator, number 7,259,705. It's available on Google as a pdf file here. In the patent they say that their active circuit's power supplies are floating; they ride atop the incoming mains waveform. The supplies are (Mains +15V) and (Mains -15V). So they can correct waveform imperfections smaller than ~13 volts. (The predriver stage gets mains ±30V rails from a low current voltage doubler).
They do a good job of disclosing the internal guts of their circuitry, including the fact that their phase locked loop is implemented in software (!). Because its output rides atop the incoming mains waveform, this device's output frequency is NOT user adjustable; it's stuck at 60Hz (or 50 in Europe).
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seems that your ac utility compnay allows heavy loading of their transformers.....keeps costs down, I suppose. In my location we have a power transformer for every 3 homes.... never see flat topped waveform.
It should not be too hard to produce a clean sinewave and run it into a power amplifier for a power source for everything except a PA (being practical).
THx-RNMarsh
Elgar was building high power conditioners in the early 1970s. They had transformers and fans but were reall robust and .1% distortion at a full 15A rms load.
However that meant serious current harmonics which radiate more.
There is no magic that a sinewave has for a rectified load. The load pulls power at the 3rd 5th and 7th harmonics not the fundametal. Create a source with those harmonics and the power transfer will be cleaner and less switching noise.
I have done this with great success. Just expensive.
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However that meant serious current harmonics which radiate more.
There is no magic that a sinewave has for a rectified load. The load pulls power at the 3rd 5th and 7th harmonics not the fundametal. Create a source with those harmonics and the power transfer will be cleaner and less switching noise.
I have done this with great success. Just expensive.
Sent from my LG-H811 using Tapatalk
Mostly loading on the distribution transformers. Its called K factor in the trade. I have heard stories of transformers failing from too much power at higher harmonics. Uusally from big motor drives and things like that. The EU has a harmonic regulation that effectively prohibits big ac powered amps but no one has noticed.
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Sent from my LG-H811 using Tapatalk
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