Why just 400 Hz?
One reason for 400 Hz, at least for amateurs, is that there are still high voltage transformers for this frequency left over from Air Force equipment.
Then again, I'll stick with my low-noise push-pull switchers from Linear Tech.
One reason for 400 Hz, at least for amateurs, is that there are still high voltage transformers for this frequency left over from Air Force equipment.
Then again, I'll stick with my low-noise push-pull switchers from Linear Tech.
Why not just use a generator to get your higher freq? You could just take a normal 120V generator and crank up the RPM so you get higher frequency and voltage. You can then reduce the voltage to whatever.
Harry,
What kind of bulbs were you using in your circuit and what amp would be best for that? Maybe I should built one more Aleph?😉
What kind of bulbs were you using in your circuit and what amp would be best for that? Maybe I should built one more Aleph?😉
jam
Hmmmmm..... maybe your right.
People please go read the stuff at
http://www.psaudio.com/power.asp
I am not telling you to go buy the stuff but he does have some great info on regeneration that led me to go build my own. Not all this stuff can be explained in two or three paragraphs.
One reason for 400 Hz, at least for amateurs, is that there are still high voltage transformers for this frequency left over from Air Force equipment........ I'm sure everybody can find those. You can try a big output transformer from a tube amp though.
Bulbs... I will have to reseach that one. Highest voltage lowest current minature bulbs with leads that I could find at Radio Shack.
You want the highest resistance measured with a VOM that you can get to make the feedback a reasonably high resistance for the op amp to drive. I will try to figure out what I used. I would buid a big Class AB amp with at least 50 volt rails. The turns ratio of your output transfomer will determine the swing needed by the amp.
H.H.
Hmmmmm..... maybe your right.
People please go read the stuff at
http://www.psaudio.com/power.asp
I am not telling you to go buy the stuff but he does have some great info on regeneration that led me to go build my own. Not all this stuff can be explained in two or three paragraphs.
One reason for 400 Hz, at least for amateurs, is that there are still high voltage transformers for this frequency left over from Air Force equipment........ I'm sure everybody can find those. You can try a big output transformer from a tube amp though.
Bulbs... I will have to reseach that one. Highest voltage lowest current minature bulbs with leads that I could find at Radio Shack.
You want the highest resistance measured with a VOM that you can get to make the feedback a reasonably high resistance for the op amp to drive. I will try to figure out what I used. I would buid a big Class AB amp with at least 50 volt rails. The turns ratio of your output transfomer will determine the swing needed by the amp.
H.H.
hmm, i know these things work but the thought of regenerating AC, only to have it converted back to DC inside your amp/preamp/whatever... i dunno... seems so... inefficient... but hey, whatever works.
i suppose regeneration is more flexible than just building a good power supply to begin with, because you can plug any traditional component into it. otherwise i'd have to redo the PS on my dvd, DAC, preamp, etc. etc. to get similar improvements in power quality. and i guess there are certain things you can do to clean up the power with AC regeneration that are harder to achieve inside a DC supply.
btw, i have tried the PS Audio 300 in my system, and while it did clean up noise and hash a lot it did have some undesirable side effects, even when using it only on my DAC. i felt it thinned out the tonal balance and made the dynamics a little less organic, so while the midrange and treble were purer i wasn't so happy with the trade-off. i'm guessing the larger units won't have this problem though.
i suppose regeneration is more flexible than just building a good power supply to begin with, because you can plug any traditional component into it. otherwise i'd have to redo the PS on my dvd, DAC, preamp, etc. etc. to get similar improvements in power quality. and i guess there are certain things you can do to clean up the power with AC regeneration that are harder to achieve inside a DC supply.
btw, i have tried the PS Audio 300 in my system, and while it did clean up noise and hash a lot it did have some undesirable side effects, even when using it only on my DAC. i felt it thinned out the tonal balance and made the dynamics a little less organic, so while the midrange and treble were purer i wasn't so happy with the trade-off. i'm guessing the larger units won't have this problem though.
[btw, i have tried the PS Audio 300 in my system, and while it did clean up noise and hash a lot it did have some undesirable side effects, even when using it only on my DAC. i felt it thinned out the tonal balance and made the dynamics a little less organic, so while the midrange and treble were purer i wasn't so happy with the trade-off. i'm guessing the larger units won't have this problem though. [/B][/QUOTE]
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I don't think you can just attribute above to ac regeneration. As you improve each component, this can show up deficiencies in others. It is worthwhile separating analogue and digital boxes connected to supply. The latter has subtle but clearly audible effects with or without inductive isolation. A transformer system can actually be easier on the ear if you don't want to invest a lot of effort.
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I don't think you can just attribute above to ac regeneration. As you improve each component, this can show up deficiencies in others. It is worthwhile separating analogue and digital boxes connected to supply. The latter has subtle but clearly audible effects with or without inductive isolation. A transformer system can actually be easier on the ear if you don't want to invest a lot of effort.
Use Of the PS300
If you use the sine wave mode do not set the frequency above 90Hz or the sound will thin out.
The unit sounds best with one of the multiwave options which you should get if you dont have it.
Jam
If you use the sine wave mode do not set the frequency above 90Hz or the sound will thin out.
The unit sounds best with one of the multiwave options which you should get if you dont have it.
Jam
i'm not sure the unit i auditioned had the multiwave upgrade at the time. that may have been why.
maybe it's just me, but i also had a sneaking feeling i could sort of "hear" the sound of the powerwave when using it... like i had another solid state amp in the signal path, albeit the impression was VERY subtle. while the sound was much cleaner i also felt it was a little sterile. you guys might think i'm just preferring the coloration of line noise but i don't think that was it... the powerwave definitely had a sound of its own though. it was not bad or anything, but it was definitely there. i probably just needed to get used to it.
maybe it's just me, but i also had a sneaking feeling i could sort of "hear" the sound of the powerwave when using it... like i had another solid state amp in the signal path, albeit the impression was VERY subtle. while the sound was much cleaner i also felt it was a little sterile. you guys might think i'm just preferring the coloration of line noise but i don't think that was it... the powerwave definitely had a sound of its own though. it was not bad or anything, but it was definitely there. i probably just needed to get used to it.
If the kind of ac power you feed your amp makes a difference to the sound, then that means the amp has a power supply rejection problem. Fix the cause of this, not the input waveform.
That said, probably the ideal wave shape to feed the ac input would be the same area under the curve as the normal sinewave half cycle but with gentle rising and falling edges and a flat top. That way the filter caps are held at the working voltage for a greater percentage of the time so less ripple and lower peak currents. Some car alternators have this kind of waveform out of the windings before it gets to the diodes.
A sinewave is definitely not the ideal waveform to feed a capacitor input filter as found in most amps. A sinewave is only the natural signature of the machine used to generate it at the power station. If transformer noise and losses and other induced noises were not a problem then a square wave would be the ideal waveshape to run on. Always at maximum, hence no ripple on the dc power rails.
GP.
That said, probably the ideal wave shape to feed the ac input would be the same area under the curve as the normal sinewave half cycle but with gentle rising and falling edges and a flat top. That way the filter caps are held at the working voltage for a greater percentage of the time so less ripple and lower peak currents. Some car alternators have this kind of waveform out of the windings before it gets to the diodes.
A sinewave is definitely not the ideal waveform to feed a capacitor input filter as found in most amps. A sinewave is only the natural signature of the machine used to generate it at the power station. If transformer noise and losses and other induced noises were not a problem then a square wave would be the ideal waveshape to run on. Always at maximum, hence no ripple on the dc power rails.
GP.
Well no, actually generally what we need is pure DC.
Some time ago I became interested in this area and looked carefully at a manufacturer’s site (no names mentioned). I was impressed by what they had to say, but became somewhat dubious when I saw something that was just plain wrong. I emailed them and they implied they were going to remove the reference from their site (and I understand they did), but it did cause me to wonder about the credibility of the rest of their “information”.
This is how I understand the principles behind AC regeneration, and I would welcome input (corrections) from others. As mentioned, we really don’t care what the AC signal is like, it’s the pure DC (and earth) that matters to us. If there is garbage on the AC line it can be filtered out fairly easily. Proponents of AC regeneration argue that because the earth path has a finite impedance, in the process of filtering, the component’s earth will be modulated by the garbage.
In commercial equipment I believe, for various reasons, the matter of ideal earthing does not receive the amount of attention that perhaps it deserves. I can see the arguments for AC regeneration may be applicable to this equipment. However as DIY builders we are not so constrained by manufacturing realities. I feel the end result could be equally achieved by various means without any requirement for AC regeneration, one of which is simply by careful consideration of the earth path.
I must admit I am lost by the logic of PS Audio’s “multiwave” if their argument about a clipped AC waveform is credible. http://www.psaudio.com/articles/power_conditioners.asp towards the bottom they suggest that a clipped AC waveform is bad because of the harmonics it contains. Fair enough, a convincing argument. The waveform shown on the Fluke’s screen looks like a fundamental plus a few low order harmonics. Because an AC transformer simply won’t pass high frequencies, it’s probably the worst you’re likely to see on the secondary windings. Now look at http://www.psaudio.com/articles/multiwave.asp the “partial square sign wave”. Looks like the same waveform that was supposed to be so terrible before. Sorry but I'm lost in this logic.
AC regeneration
Go back and read the PS site again as it is very informative and pretty free of BS. Getting rid of the garbge on the AC is more complicated than you might think as there are noise components from DC to many hundreds of Megahertz on an AC line. I have measured up to 20% distortion routinely. Torroid power transformers saturate at DC and very low frequencies very easily. TThe bandwidth of a torroid power transform can be over a hundred KHz as passes noise quite well. RF can very easily easily. Having built my own AC regeneration i can testify that it works quite well and was worth the effort.
H.H.
Go back and read the PS site again as it is very informative and pretty free of BS. Getting rid of the garbge on the AC is more complicated than you might think as there are noise components from DC to many hundreds of Megahertz on an AC line. I have measured up to 20% distortion routinely. Torroid power transformers saturate at DC and very low frequencies very easily. TThe bandwidth of a torroid power transform can be over a hundred KHz as passes noise quite well. RF can very easily easily. Having built my own AC regeneration i can testify that it works quite well and was worth the effort.
H.H.
Harry I have read the site, which is why I asked the question about the waveforms and provided the links as such.
As I mentioned it is not how much noise or distortion that is on the AC waveform that is the issue. What is important is obtaining clean DC and earth. There are other techinques that can be used to achieve this besides AC regeneration.
As I mentioned it is not how much noise or distortion that is on the AC waveform that is the issue. What is important is obtaining clean DC and earth. There are other techinques that can be used to achieve this besides AC regeneration.
What's on your AC line
See the garbage with a spectrum analyzer --
there was an interesting case in Cincinnatti just resolved between Cinergy (the electric utility) and an a.m. broadcast station (WLW) which highlights a problem which audio enthusiasts should pay more attention to -- seems that the static line of the 345kV transmission line was improperly grounded. Thus the static line was acting as a gigantic antenna, modulating the power line with a combination of what appeared to be a spark-gap transmitter and an am broadcast station.
I think that a lot of the problems referenced by this discussion would go away with better grounding schemes.
with regard to the sine and modified square wave -- this is akin to what Linear Technology does with their low noise push-pull switcher -- softening the edges.
See the garbage with a spectrum analyzer --
there was an interesting case in Cincinnatti just resolved between Cinergy (the electric utility) and an a.m. broadcast station (WLW) which highlights a problem which audio enthusiasts should pay more attention to -- seems that the static line of the 345kV transmission line was improperly grounded. Thus the static line was acting as a gigantic antenna, modulating the power line with a combination of what appeared to be a spark-gap transmitter and an am broadcast station.
I think that a lot of the problems referenced by this discussion would go away with better grounding schemes.
with regard to the sine and modified square wave -- this is akin to what Linear Technology does with their low noise push-pull switcher -- softening the edges.
Re: AC regeneration
Having built my own AC regeneration i can testify that it works quite well and was worth the effort.
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HH
Can you pl post your design?
FM
Having built my own AC regeneration i can testify that it works quite well and was worth the effort.
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HH
Can you pl post your design?
FM
New (?) idea:
How about regenerating the ac line by a small added signal ?
--> only rel. small power amp needed, if max. distortion on line is about 10% and system power cons. about 200W, a 25W amp would be sufficient to clean the ac line and lower the virtual impedance of the line. What do you think about ?
(added simpl. schema.)
alf
How about regenerating the ac line by a small added signal ?
--> only rel. small power amp needed, if max. distortion on line is about 10% and system power cons. about 200W, a 25W amp would be sufficient to clean the ac line and lower the virtual impedance of the line. What do you think about ?
(added simpl. schema.)
alf
Attachments
clean AC
The commercial boys will never do this because it is too expensive, but as DIYers we can "play".
Get yourself a couple of AC motors out of a clothes dryer or some such. Connect them with pulleys and a V belt. Connect one to the AC line and use the other as a generator. No "stuff" from the AC line will get thru this "mechanical filter". If you want to eliminate voltge sags afix a flywheel on to the generator shaft. Decades ago I worked in a plant that used a similar setup to power the plant's central computer. The electricians would talk in awe about how clean the conditioned power was.
If you want to use a frequency higher than 60 Hz, then instead of using a second AC motor as a generator, go to a junk yard and get an alternator out of a car. Internally the alternator generates three phase AC, then rectifies it and sends the resulting DC to the outside world. Take the alternator to an automotive electric shop and ask them to remove the diodes and run the three phase wires out of the case for you. This AC voltage will be on the order of 7 to 8 VRMS (more on this in a minute.) in the delta configuration. Figure out what AC voltage you need to get the DC voltage you want and use 3 appropriate step up transformers. You can vary (regulate) the output voltage by varying the field current. You can vary the frequency by changing the size of the pulleys on the generator and/or alternator shaft.
The commercial boys will never do this because it is too expensive, but as DIYers we can "play".
Get yourself a couple of AC motors out of a clothes dryer or some such. Connect them with pulleys and a V belt. Connect one to the AC line and use the other as a generator. No "stuff" from the AC line will get thru this "mechanical filter". If you want to eliminate voltge sags afix a flywheel on to the generator shaft. Decades ago I worked in a plant that used a similar setup to power the plant's central computer. The electricians would talk in awe about how clean the conditioned power was.
If you want to use a frequency higher than 60 Hz, then instead of using a second AC motor as a generator, go to a junk yard and get an alternator out of a car. Internally the alternator generates three phase AC, then rectifies it and sends the resulting DC to the outside world. Take the alternator to an automotive electric shop and ask them to remove the diodes and run the three phase wires out of the case for you. This AC voltage will be on the order of 7 to 8 VRMS (more on this in a minute.) in the delta configuration. Figure out what AC voltage you need to get the DC voltage you want and use 3 appropriate step up transformers. You can vary (regulate) the output voltage by varying the field current. You can vary the frequency by changing the size of the pulleys on the generator and/or alternator shaft.
WOW, a Ward Lenard Drive. Yup had those on an old mainframe I used to service, and on my Monarch 10ee toolmakers lathe as well.
Makes my class A amplifiers look efficient!
Cyclotronguy
Makes my class A amplifiers look efficient!
Cyclotronguy
Lathe?
I can understand why they would do this for a mainframe but why go to that trouble for a lathe?
I can understand why they would do this for a mainframe but why go to that trouble for a lathe?
lathe
I think constant torque and speed is critical to certain job depending on the material and cutter being used. It can affect the quality of the finished product on a lathe.
I may be wrong.
Chris
I think constant torque and speed is critical to certain job depending on the material and cutter being used. It can affect the quality of the finished product on a lathe.
I may be wrong.
Chris
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