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71.0.209.249
In Reply to: RE: Great Post !!!! posted by Garg0yle on January 12, 2015 at 12:39:27
To justify your VERY misguided intellect .
Edits: 01/12/15 01/12/15Follow Ups:
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.
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