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In Reply to: RE: Great Post !!!! posted by Garg0yle on January 09, 2015 at 16:29:56
Or mine:
Follow Ups:
gargoyle -what happens if you extend out beyond 4 seconds and allow the 150uf cap to discharge?
I *think* the idea is that the low storage supply would recover from overload faster. it's hard to see that in a small window of time.
yes it drops 1 or 2 volts faster than the supply with more henries and capacitance, but also recovers faster. the other thing is the belief that while the 150uf capacitor is sinking current to recharge the output tube is starved for current, whereas the smaller caps won't have so much of an effect.
I think another issue here as the simulations get more elaborate, it's hard to nail all the variables for an accurate simulation.
the document that jeff speaks of, where he put all of the JLH posts he found that reinforces his power supply ideas, is VERY good IMO.
at some point if you guys are really curious, spend the $50-$100 on some chokes, mock up the supply and get your test gear out.
I'd recomend the flywheel stuff over this more recent power supply...
the stuff to use that is proven is the triad c56u and 2 stages of triad c40x.. hammond 159za is a bit better than triad c40x but costs about double.
three stages, .035h, 15uf, .3h, 50uf, .3h, 50uf
very low dcr toroid transformers where used by JLH. he got his "dynamic impedance" down to around 78 ohms with cree diodes in a bridge. not 650 ohms, he'd call that junk. 200-250 ohms with tube rectifiers.
he also did test with a frequency generator and found very little change in b+ across the frequency range, and was satisified with supply impedance at that point.
Jeff's got the document, and I think its worth a read. goes WAY beyond Jeff's interpretation..
I wonder how all the odd TW/DLM power supply configurations affect IMD measured at the output of the amp?
ARTA has a few preset 2 sine tests and a user defined option.
Have you played around with any of those measurements?
"gargoyle -what happens if you extend out beyond 4 seconds and allow the 150uf cap to discharge?"
-For curiosity sake I will see what I can do.
"I *think* the idea is that the low storage supply would recover from overload faster. it's hard to see that in a small window of time."
-I still fail to see the value in a fast charge time if it sounds bad during use.
Don't forget that the B+ voltage will be wildly swinging up and down simultaneously for the higher frequencies. This undulating reference will inter-modulate with the higher frequencies garbling the sound.
"yes it drops 1 or 2 volts faster than the supply with more henries and capacitance, but also recovers faster. the other thing is the belief that while the 150uf capacitor is sinking current to recharge the output tube is starved for current, whereas the smaller caps won't have so much of an effect."
-As I mentioned on the other page, it is the area under the curve that counts.
Capacitance fills in the dip. "starved for current" is kind of a red hearing, the tube will prefer to pull the current from the last cap anyways. It does not compete with the capacitor, it attempts to empty it.
So long as the voltage is higher then then ground, voltage will flow from the capacitor.
Farkwin supplies aren't "fast", they are saggy.
Those step vertical waveforms are there because it dropped like a stone and there is nothing to charge.
"Fast" would imply you had a transformer rectifier combination that could deliver much more current then typical devices used.
Since the Farkwin uses a tube, and usually the cheapest iron this isn't the case.
"I think another issue here as the simulations get more elaborate, it's hard to nail all the variables for an accurate simulation."
-It's OK if the results are somewhat arbitrary. We are comparing topologies.
"the document that jeff speaks of, where he put all of the JLH posts he found that reinforces his power supply ideas, is VERY good IMO."
-I've read too many ridiculous things claimed by Drlomu over the years to go chasing unicorns.
"at some point if you guys are really curious, spend the $50-$100 on some chokes, mock up the supply and get your test gear out."
-I've read too many ridiculous things claimed by Drlomu over the years to go purchasing unicorns.
Don't forget the humble PC is a pretty good piece of test equipment as demonstrated by this thread.
"I'd recomend the flywheel stuff over this more recent power supply... "
-Sounds catchy!
"three stages, .035h, 15uf, .3h, 50uf, .3h, 50uf
very low dcr toroid transformers where used by JLH. he got his "dynamic impedance" down to around 78 ohms with cree diodes in a bridge. not 650 ohms, he'd call that junk. 200-250 ohms with tube rectifiers."
-Seems like a lot of fuss to try and compensate for low capacitance, not to mention noisy.
"he also did test with a frequency generator and found very little change in b+ across the frequency range, and was satisified with supply impedance at that point."
-Good for him.
I don't think Drlomu should drag someone into the mud based on some half assed implementation of something he read somebody else do.
I'm no EE, but I don't think the term "Dynamic Impedance" is being used properly, or is even relevant beyond the application cited.
A quick look at yesterdays sims show the voltage wavers steady after the rectifier. Dynamics seem to be pulled from the caps which seem to be much lower then the "78 ohms" you implied to be a good number.
Everything has trade-offs. My preference for power supplies are slow to charge at turn on.
This is a good compromise because the tubes are warming up anyways.
Slower to charge is also slower to drain which equals a longer amount of time closer to the optimal B+, much stiffer too.
To justify your VERY misguided intellect .
Edits: 01/12/15 01/12/15
Jeff, it is hard at times to figure out quite what it is that you believe. You surely must agree that the output voltage of your low C, low L power supply fluctuates more with the audio signal than a high C, high L supply will do? Is this, at least, an area of common ground between what you are saying and what many of the rest of us are saying?
If you want to argue that despite fluctuating more, or indeed perhaps because it fluctuates more, it "keeps better time with the music," then that could be a separate discussion. (I don't know what "keeps better time with the music" is supposed to mean, but still, that is a discussion one could have.) But the fact that small C and L will cause a greater level of fluctuation at the audio frequencies can surely not be in dispute?
Chris
The stiffer a power supply is--- that is, the less it current-starves the amp stage it is powering, the better it will follow the "groove" of the music. It is IMPOSSIBLE, therefore, to follow the music's groove with a power supply that fluctuates (sags) enough to momentarily current-starve any amp stage that it is powering.Current starvation can come from several sources:
(1) Capacitors that store too much energy and release it too slowly. The cap's re-charge cycle takes current away from what is to be powered, and the release cycle of a large cap simply doesn't even get started (release isn't fast enough) until the musical transient has come and gone.
(2) Current starvation can come from a power transformer that's operated too close to its rating. Run about 30% of the rating, or less.
(3) Current starvation can come from too much stored inductance in chokes-- as in capacitors-- energy charge-up hogs current away from the device to be powered and energy release is delayed for too long.
(4) Current starvation can come from unnecessarily high resistances in the wrong places. These can be high-DCR chokes (anything over 20 ohms in most cases in tube amp power supplies).
(5) Current starvation can come from attaching devices onto the plate or cathode of a tube, in the attempt to correct for a sagging power supply. Examples of this include CCS devices, SRPP, etc., and several more.
(6) If a current-starving (under powered, or slow due to large capacitors, high value chokes, etc.) power supply is being operated, use of these (above) correction devices will usually improve bass performance at the expense of causing some current starvation of High notes that are extended and extremely dynamic, such as repeated cymbal clashes-- something very few amps ever get right-- so no one should feel bad if he's never heard an amplifier do it right. The use of these add-on devices nearly always also cause slight-- or sometimes worse-- degradation of signal purity, similar to a Tetrode or a Pentode VS a true triode-- that is-- slight signal homogenization and slight (or worse) image smearing.
The above effects (defects, actually) are euphonic and pleasing to many listeners because by homogenizing some signal information together, they more fully "flesh-out" the music-- it sounds solider and fuller than it actually is. This problem largely disappears with the use of medium or lower-efficiency speakers (usually under 96 db/watt) simply because those speakers can't reproduce it, but becomes apparent as an unwanted musical distortion when powering High-EFF, speakers that have large radiating surface areas, and have cables/wiring that is clean, efficient, and wideband.
The above are observed results and are not a set of personal opinions.
---Dennis---
Edits: 01/13/15 01/13/15
" The above are observed results and are not a set of personal opinions.
---Dennis---"
Since you observed these results instead of measuring them, they are all personal opinions. Further more, claiming that improved bass and more fleshed out sound is the result of a defect is incorrect. If an amp reproduces an acoustic bass in a natural manner, it can't be said to have exaggerated bass. If the mids and highs have a full sound that the original music has, it is correct.
Using examples like these as an excuse for an amp having a thin sound or lacking in bass is not being true to the source material. You may prefer that type of coloration but others may prefer a more natural sound.
Why bother to answer this. Anyone care to try his hand at it?
---Dennis---
" Current starvation can come from several sources:(1) Capacitors that store too much energy and release it too slowly. The cap's re-charge cycle takes current away from what is to be powered, and the release cycle of a large cap simply doesn't even get started (release isn't fast enough) until the musical transient has come and gone."
No. This is not correct. The larger the capacitor, the more steady the voltage across it will be under a given fluctuating load current. This is just a basic fact of how capacitors work.
Chris
Edits: 01/14/15
Sorry, but you are ignoring the re-charge cycle particularly. When a cap is recharging it is HOGGING CURRENT AWAY FROM the load.
When it is too large for the application, it's discharge/energy release cycle is VERY SLOW----wwwwwwwwwwwwww! YOU CAN HEAR THAT! It is NOT Thrilling!!!!!
This is so blatantly obvious to those builders that have experimented with capacitor and choke values in designing amps, that it's become ridiculous and repetitive to keep on repeating it.
Those old theories taught in those old tube books are not high fidelity-to-signal.
They NEVER WERE. I've used just about every tube amp out there for some sort of commercial app-- not all of them, but most of the best ones.
They DO NOT reproduce music RIGHT! NONE of those tube amps ever did...
Nothing built with those old, obsolete theories does today.
This is SO EASY to test! EASY! Get a Spectral DMA200S amp, or any 200 watt or greater Boulder, or a large, newest Bryston., etc., and see how it handles fast transient attacks in music.
Then, get out your tube amps-- I don't care-- get the best you know of, and watch them fall all over themselves trying to get out of the way of a GOOD amp.
Well, it just so happens that I designed a TUBE amp that actually works. For a while, it was the ONLY one. Now, it's starting to get some decent competition, and that is good-- VERY good. It means that I can give this up, retire, and have a good time.. That's right, we actually reproduce music, something tube amps normally fall down at.
Better look out! That old crap might include your amps if you followed all those old cap and choke theories for old push-pulls and tried to stuff them into a S.E. amp. Yes, it will sound slow-- just like all those other tube amps of yesteryear-- perhaps with today's VASTLY better resistors and caps, it will be a bit better, but will still fall short as far as reproducing today's best recorded music is concerned.
Someday, what's going on here will be common knowledge. Today, you can still get away with throwing darts at people like me who know what's up-- but all you're getting away with is Old Theory-- not anything scientific or provable by actual measured and listened-to musical performance.
Oh yes, it's s good idea to stop obsessing about what those old-fogies were measuring to sell cheaply designed amps with, and start measuring what actually matters-- musical reproduction SPEED, RESOLUTION, and DYNAMICS-- both Micro and Macro.
We're Light Years beyond that old stuff now. Your still popular Theory Train is slowing down and it's railroad tracks are starting to widen and loosen.. Reality could lie around the next Bend....
---Dennis---
You like the sound of a sloppy pose supply. There is mother wrong with that. At least you know what it is, so you can duplicate it in your production.
> Those old theories taught in those old tube books are not high
> fidelity-to-signal.
> They DO NOT reproduce music RIGHT! NONE of those tube amps ever did...
> Nothing built with those old, obsolete theories does today.
Oh, yes, all names and brands from Frank McIntosh to Bob Cordell, from Marantz to Sony must be wiped out from the history of audio in favor of Great Fraker Theory.
Peacockery and laughing-stock.
"We're Light Years beyond that old stuff now. Your still popular Theory Train is slowing down and it's railroad tracks are starting to widen and loosen.. Reality could lie around the next Bend...."
OK, so you like the sound that comes from a floppy power supply that wobbles with the load. Nothing wrong with that, if it's what you enjoy.
Chris
You are only talking about a SMALL portion of the power supply in my amps, and its an incomplete picture, not representative of whats really going on.
My power supply, unlike many / most others, is "all over the amp " and we have said this, going back many years now.
For example, I have a simple one-part shunt regulator, located ONLY 1/8 th of an inch from the point of use, the front end's plate resistor. It shunts over 15 times the audio current, than what the audio stage uses. Ninty percent of what we hear in a two stage 2A3 amp is the front end. WHAT do you think that Shunt Regulator does, to lock-in high performance??
And I am not even discussing the additional use of a Dennis Fraker " Final Filter", L/C, located 1/8th of an inch from the input stage's plate resistor. Who has those TWO items in their amp designs, no one except Dennis and I.....and anyone we have mentored.
So Chris, we can't intelligently discuss my preferred amp designs, unless we look at the whole circuit. My power supply, copying Dennis', is ALL OVER the AMP !! What you are doing is trying to play poker with one third of the deck !!
Enough of this .
Jeff Medwin
"So Chris, we can't intelligently discuss my preferred amp designs, unless we look at the whole circuit."
Maybe you could post a schematic, and then we can discuss it?
Chris
15 times .5ma is 7.5ma. So there is 8ma. total of which only .5ma. is moving.In the old days they call this form of voltage regulation a "clamped down" PS.
It does a good job preventing voltage fluctuations caused by the .5ma that is moving but it does nothing to prevent the voltage from changing because the source voltage is changing do to the large current swing of the output stage and a poorly regulated supply that's feeding the whole thing.
In this case the voltage regulator would need to regulate against both sides, the changing load and the changing source, to be of any real benefit.
I hope I wrote that clearly enough to be understood.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 01/13/15
Not even going to read it lol.Judging by the picture you posted you don't grasp the difference between energy storage device and something that dissipates energy.
Its very simple Drlomu it goes like this, I will even use your attachment for an example.
Power from the voltage source will prioritize the cap because it is the lowest impedance. 36 ohm vs 650 ohm
The tube conversely loads the capacitor because 36 ohm is lower vs whatever the resistance is of the choke etc.
It's a relay.That is why it is called a reservoir capacitor.
Similar to a water reservoir that is designed to collect and store sporadic additions of water, that can later be distributed in a even controlled fashion. Through valves even.-The reservoir needs to hold enough water to get you by between rainfalls.
-You need more rain then the water you consume per year.The bigger the reservoir is, the less it is going to drop in level per dry cycle. This is of particular interest to us because this water line is used as our voltage reference.
If this waterline stays fairly constant, then you can control valves in a predicable, dare I say linear fashion, because the water pressure is nearly always the same.
Edits: 01/12/15 01/12/15
Very simple. A friend's son was granted an interview with Microsoft for a summer internship when asked to explain the concept of "reduction" to a child. His example was Russian Nesting Dolls. Perfectly simple to understand.
my only long winded point being that what Jeff is describing can be made to work and don't dismiss it because of his troll like ways of spreading the information.
there is an EE or two out there that have spent time making it work that like variations on the "low everything supply." people with a lot more education and understanding on electronics than myself. jeff's gorilla marketing can be frustrating, but he means well.
Why is it so hard for people to say they like the way a sloppy supply sounds and measurements don't matter.
GG,
This is really sort of funny !! You have it very wrong. Please send me your private email address, and I will email you, as attachments, all the SWENSON and HASQUIN posts, in chronological order, for you to read and digest some.
If you don't want me to contact you directly, no problem, find a Forum Member we both know, and It could be forwarded, them first, to you second.
I understand your line of thought, its just that it is not correct. The first 50 mS. are "free" according to SWENSON's measurements of music.
Your call on proceeding, I have the posts in Word Files. I am just being fair and open with you, certainly you recognize that.
Jeff Medwin
Edits: 01/10/15
I can't see GEO's last two posts.
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