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136.2.1.102
hey-Hey!!!,
For a Class A, PP amp the current is near constant. I don't see where the use in building a PS that settles quickly to a new current demand level lies; if the PS takes 2-3 cycles of low frequency change in demand to settle to its new value this would be a good thing, yes? The demand would change in the mean time and B+ would be undisturbed.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Follow Ups:
Christ on a bike . Why do we keep on doing this ? When will it end ?
Al
I thought I might get a reasonable answer, or at least logical reasoning as to why one characteristic is required or something. Guess I expect too much anymore.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I cannot be convinced to use less than Crit chokes. However low DCR is very good IMO. I also like damper tubes best for rectifiers.
"Sound" thinking! I totally agree (for whatever that's worth).
IMO the PS for a PP amp certainly is not as critical like a SE power amp! You see even though I like SE sonics, I believe I can build a PP amp that will have the SE midrange magic & be more dynamic at the same time.
I built just one PP amp that was very close to SE sonics. Thus, I have a tendency to experiment more with PP.
---You see even though I like SE sonics, I believe I can build a PP amp that will have the SE midrange magic & be more dynamic at the same time.
I came to a very similar conclusion before I built my first amp...and have seen zero evidence that it is an incorrect one. There is no SE amp plan in my future...:)
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Neff,
I am not so sure about that, the P-P amp gets "TWO pulls" on the power supply filter, from the Finals tubeS, for a waveform to complete.
Ohh yeah, I didn't say it well, but you know what I mean. P-P which splits the wave, in MY way of thinking, MAY be twice as critical on the filter.
Jeff
Not so.
PP stands for push-pull. In a class A push pull amp, the current drawn by one tube is the complment of that drawn by the other, so that the sum of the current drawn by the two tubes remains constant. The power supply sees a constant current draw. Both tubes are working all of the time. As the current in one tube increases, that in the other decreases.
In class A, there is no such things as 'two pulls'.
Now if you are talking about class B, that's a different matter. In class B, the current drawn by one of the two tubes goes to zero (cutoff) during part of the waveform. So, I guess you can say that there are 'two pulls' per cycle (asuuming a symetric input signal).
"Class B - 50% of the input signal is used (i.e., the active element works in its linear range half of the time and is more or less turned off for the other half). In most class B, there are two output devices (or sets of output devices), each of which conducts alternately (push–pull) for exactly 180° (or half cycle) of the input signal.
These amplifiers are subject to crossover distortion if the transition from one active element to the other is not perfect" (from Wikpedia)
Each tube in P-P class A sees current flow to both tubes but out of phase from the other during each cycle.
So think of a PP amp as a bidged pair of SE amps sharing a single PS. That is real Class A...not this 'Class A for n Watts, and XX Watts at full power' cow chips spawned by some dishonest marketing department.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Douglas,
Wouldn't that describe a "parallel" OP scenario not PP?
Mitch
nope...parallel would be connecting the outputs ground-to ground, and 8R tap to 8R tap( for a 4 R load ) and feeding the amps a single signal. bridged would be ground to ground, and an 8R load across the 4R taps whilst feeding the amps a balanced signal( PP ).
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I was referring to their actual operation, not the physical connection.
Their 'actual operation' requires a certain physical connection, as well as the blaanced signal presented to the properly rig'd combination. Do you see the difference between the two scenarios I presented?
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Yup.
Thanks,
Wheeze
Hi mikeyb,
This you stated is "by the book therory" regurgitated:
"PP stands for push-pull. In a class A push pull amp, the current drawn by one tube is the complment of that drawn by the other, so that the sum of the current drawn by the two tubes remains constant. The power supply sees a constant current draw. Both tubes are working all of the time. As the current in one tube increases, that in the other decreases."
I am TOTALLY aware of this "by the book" theroy, and what myself, and two others, (Chris O and Wheezer) have already posted is, A1 isn't excatly so simple in reality, and that the theory may not be 100% correct in practice.
Sometimes, questioning, and doing "out of the box" thinking, can lead to good new things happening.
Jeff Medwin
What you stated is that 'the P-P amp gets "TWO pulls" on the power supply filter, from the Finals tubeS, for a waveform to complete.'
On what do you base that statement?
Lacking any kind of proof of that statement, I'll go with the theory, thank you.
Nothing settles faster than a supply with an infinitely large output cap with infinitely small ESR. If you have that, class of operation is not an issue.
--------------------------
Buy Chinese. Bury freedom.
.
"It is a simple fact that the capacitor will always rob the output tube for available current in order to maintain its charge."
And thank goodness for that - it's the only thing standing between us and feeding 120Hz directly to the amplifier. That article really is rubbish.
--------------------------
Buy Chinese. Bury freedom.
""It is a simple fact that the capacitor will always rob the output tube for available current in order to maintain its charge.""I don't understand why JLH would think that the "available current" is limited to the point of being a problem.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/08/11
It is just two simple parallel resistors.
TonyB
But the boys who are resistant to anything different will obfuscate the simple truth of two parallel resistors, and simply try to wear some of us down.
Fact is, we use the more modern approach, and are liking it a whole lot. Thats what is good !!
I think we should just give-up on the usual bunch of Forum jokers, let them sow what they reap. They deserve to listen their own implementations, as far as "I" am concerned.
Jeff Medwin
Call him, order some of your "DrLowMu" chokes.
Be warned it won't be a pleasant learning experience.
BTW it's not just L input chokes, any choke in the circuit must be rated for that load. O/W it's nothing more than a resistor.
Cheers Jeff!
Regards,
Joker
Hello Mitch !!
No need to yell on Forum with all capitals.
Jack can do and build and THINK whatever he wants, I don't give a flying rip Mitch. I have A-Bed ALL of this since 1982, a great many times, and I certainly KNOW what I hear. You should do whatever you like, believe what YOU want, and order parts from anyone!
I custom design and have built (for me) exactly what I want and need in power supply parts, in all details, and have been doing so for several years now.
I have been able get about double the performance / specs of what people can buy commercially. I'm truly loving it!!
Jeff Medwin
Your pigheadedness proceeds you Jeff!
You get what you deserve here, sad to say.
Mitch,
Absolutely, and it is certainly not "sad to say", because it is twice as nice as anything you use.
Jeff Medwin
nt
.
"usual bunch of Forum jokers"
Hmm, I believe that you were the one who said "Quit 'yer silly flaming"
Because as delta V becomes larger, delta Z must go down if current draw is held constant. Or even worse, delta I goes up and results in an exponential reduction in capacitor Z.
A capacitor becomes a very low impedance current sink while it is trying to re-establish its charge current. (Ever try to charge a large cap without a series resistor before?) This low impedance current sink behavior directly competes with the output tube. Due to the high internal impedance of tubes, they don't have a chance against the capacitor. The capacitor will get its share well before the output tube. This prevents the output from performing exactly to its drive signal and you get a shift in the operational point.
There are two basic things that can be done to help reduce this problem. 1.) Reduce the series resistance of the power supply chain (i.e. low DCR) so the capacitor can recover its charge much quicker 2.) Use smaller capacitors.
I have found that by using the above two methods along with the Flywheel L1/C1 combo to be a higher performance power supply than my previous critical inductance power supplies. I really don't care what other people think. I'm not trying to convert anyone here, just sharing my results.
-Henry
"The capacitor will get its share well before the output tube. This prevents the output from performing exactly to its drive signal and you get a shift in the operational point."Please show me this.
I have said before, if this theory is correct we should be able to see it.
A scope on the B+ of the output transformer (while playing music) will show AC if the supply is not supplying the current that the tube wants.
I've done this with both a low capacitance, low inductance, low DRC supply and my critical supply. Both amps were SET 2a3.
The supply that you say should have been starving the output tube showed nothing.
The supply that you say should have been starving the output tube less showed a lot of AC.
It's interesting that you are concerned about starving the circuit of current but at the same time your supply has the rectifiers turned off for a good deal of the time.
Where does the current come from while the diodes are turned off?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/09/11
Does having continuous diode conduction really sound better? Do we really know for certain? When I look backwards into the power supply I see an open electrical pathway for all the garbage that lives on the line voltage. Would it be possible that short charging bursts that limits an open pathway to line noise and garbage can sound better? I believe if the charge currents are well within the specs of the power transformer and chokes that the perceived negative attributes don’t apply. Why not charge quickly and get out of the way? A forward biased diode whether solid state or vacuum will pass AC noise.
"A forward biased diode whether solid state or vacuum will pass AC noise"
Then you should be able to show me that as well.
But that is not what we were talking about.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
If a forward biased diode couldn't pass AC then LED biasing of tubes or other devices would be impossible.
I thought part of the discussion was whether it is more desirable to have your diodes aways conducting current?
How can a diode pass alternating current, whether it's foward-biased or not? I think you're a little confused here.
The DC passing through the forward-biased diode can be MODULATED by a signal. That is NOT AC.
"I thought part of the discussion was whether it is more desirable to have your diodes aways conducting current? "I thought we were talking about the last cap in the supply filter stealing current from the circuit? And where that current comes from in the first place, etc...
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/10/11
and if C1 needs to be recharged won't it be better is there is charging current flowing to C1 all the time instead of just in pulses?Here we have the current through C1.
Everything on the graph below the "0" mark is current going out of C1 to fill the needs of the rest of the filter and the circuit.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/09/11 03/09/11
Red is current through L1
Green is current through C1
Yellow is current through C2
And a non-critical, low storage supply filter.
Now, which supply is more likely to starve a circuit of current?
Look at how much more the current delivered is dependent on stored energy in the "low storage" supply.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre'
What's the current sink settings you're using?
Mitch
That is shown on the screen shots.
I think it's 60ma. for the one and 64ma. for the other.
If you're asking what current step I'm using the answer is none.
A current increase will only makes things worse for the "low storage" supply.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
If you're asking what current step I'm using the answer is none.
Yes, thanks.
"This low impedance current sink behavior directly competes with the output tube. Due to the high internal impedance of tubes, they don't have a chance against the capacitor. The capacitor will get its share well before the output tube."
There's not one iota of engineering truth to this. There's no "first," no "last," only impedance. If in fact the components ahead of the capacitor are unable to keep up with current demands, that's an entirely different and unrelated issue. None of this legitimately speaks to the performance of the cap or its interaction with the load.
--------------------------
Buy Chinese. Bury freedom.
So you are denying that there is any truth to all the EE books that state that the impedance of a capacitor varies as dV/dI changes. If you want to throw all physics out the window its fine with me. I really don't care.
Of course not. You are just not applying the 'rules' correctly. The power supply filter is not just a capacitor; it's a nework of Ls and Cs and Rs. You have to look at the total circuit.
Run a simulation of capacitor current versus time in response to a change in load current - even PSUD2 (not the most accurate simulator in the world) will show you that the capacitor does not "hog" the current.
Last time I checked PSUDII did not have provisions for simulating an output tube.
I believe that the 'discussion' revolves around power supply step response (a change in the current drawn by the output tube), which CAN be easily simulated with PSUD2. More sophisticated simulators (SPICE) can simulate an AC current load, which may be more germane. Either way, you will see that a 'big cap' is not the evil current hog that you claim.
No one is denying that. What isn't true is that the cap will "get it's" first.
The total load is just, the total load. Both will get their percentage at the same time.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Yes, Ohm's Law tells us that the lower impedance device will get a larger percentage of the available current. The larger you make the cap, the larger the percentage of available current resouces are gobbled up by it. That's the problem with large caps.
Yes, I agree that the lower impedance will get more of the available current but that's not what you said before.You said that the cap would gets it's current WELL BEFORE the tube. As in time.
Here's the quote;
"The capacitor will get its share well before the output tube."
This is what TK was objecting to.
There is no first or later. Both loads (the cap and the tube) will get their current share at the same time.
So, I hope you can see that TK was not throwing out what's in the EE books.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/10/11
Just so we don't get confused, those results are:
You like the amp built with the flywheel topology better than the critical L ones you had before.
The rest isn't a result, or even legitimate conclusions.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
hey doug, you and I have met a few times and last we talked was at a swap meet...still looking forward to getting to your place to hear your setup!
maybe I can even drag an amp or two along with me.
I've built a "flywheel" based supply now and am quite happy with it, however in fairness have yet to build a critical L supply.
I most certainly will, because I would like to compare them.
Drop me a note through the asylum mail; I'd love to have you over for a listen.
Best Regards,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Everybody is capable of reaching rather strange conclusions. The capable folks will realize a new understanding is required. The frauds will not.
Recall if you will the discussions resulting from a question on loading delivered to a PP, Class A output stage. The logic displayed there was truly amazing, and totally incorrect in a few( and often repeated ) cases. I am sure we could dig up a few of those posts...:)
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
You are making a fool of yourself TK.
Jeff Medwin
TK is perfectly correct in what he says.
Are we just going to ignore Ohm's law regarding parallel resistances then Ray ???
You are, and Ohm's Law trumps Ray Moth's opinion every time.
Jeff Medwin
Who's talking about Ohm's law? Don't change the subject, just to try to defend a piece of nonsense.
You have been consistently wrong on the subject for at least six years now. You have ever heard it, you have never built it. Thats fine with me !
Ohms law below. Why do bother to mess with you ??? Because I find the un-truth repugnant.
Jeff Medwin
How can I have been consistently wrong on a subject that I've never commented on before?
You referred to some half-baked post from a previous thread which made claims about disadvantages of large PS filter caps. TK said it was rubbish. You said he was making a fool of himself. I said TK was perfectly correct in what he was saying.
Now, suddenly, I'm accused of defying Ohm's law and being wrong for six years? And what is it that I've never heard or built? If you're talking about that silly LSES/LIES thingy of yours, forget it -- this thread is NOT about that. You're thread-jacking.
Start your own freak'n forum.
On second thought, it's kinda fun having a self deprecating punching bag for all to use.
Kind of reminds me of the "I can prove I have eleven fingers" gag my dad used to pull on me when I was in nursery school. You know:"Ten, nine, eight, seven, six... plus five is eleven."
You can say anything you want ("It's just two resistors in parallel") but that doesn't make it valid technically.
I'm not saying this has any bearing whatsoever on how the amplifier sounds to you, but the logic is about as valid as my dad's eleven finger demonstration.
99% of the technical debates on this forum revolve around misinterpretation (by both sides) of valid engineering principles.
-Henry
Edits: 03/11/11
Hello op48no1,
You state, "I'm not saying this has any bearing whatsoever on how the amplifier sounds to you,"
Well, since I have to LISTEN to music through the amp, how it sounds to me is my total priority. I wouldn't be happy with an amp that is theoretically logical, but sounds like (most) amps sound to me ! Your priorites, in audio, and on this Forum, differ somewhat from mine. Whatever is "right" for each of us, I say, is what matters sir. Regards.
Jeff Medwin
But regardless of our listening preferences or priorities, don't you agree that when we make our cases on the public forum that the arguments should be logically and factually consistent? If we post a technical argument, shouldn't that argument be technically valid, regardless of which side we're trying to defend?
In other words, if we have opposing points of view, but we both use technical arguments to defend our positions, if I make valid technical arguments, does that mean, necessarily, that you have to make invalid ones?
So the "parallel resistor" analogy is just wrong. Accepting that fact doesn't mean you're on my side. It just means you need to find a better technical argument to defend your position. Doing so would raise the quality of debate for everyone. And, heck, you might learn something.
Do you see the point?
-Henry
Hi HP:
You state this : "when we make our cases on the public forum that the arguments should be logically and factually consistent? If we post a technical argument, shouldn't that argument be technically valid, regardless of which side we're trying to defend?"
I do not use this Forum to argue, or be technically validated.
I just report my experiences, building and listening. I just care about what it sounds like, and how to best execute something. It is YOU and others who seek to know "WHY" - and answering those questions is your bag, but frankly, it is only of casual interest to me.
The reason for something to work, may or not be correctly ascribed by those seeking understanding. I care more about the results, how it sounds, and how I personally can get the results, than WHY it theoretically may (or may not be) a valid reason.
So HP, as I originally stated in this post's title, we come to this Forum with different priorities and viewpoints.
By the way, I am on a week's vacation. I am spending the whole time at a friend's home and lovely audio lab in the Chicago area. Tomorrow night we possibly get to do an organ recording. We have had at least three break-throughs on design changes, so when I go home, I expect my audio equipment to play at a whole new - and better - level. This has really been lotsa fun !!
Jeff Medwin
"I do not use this Forum to argue, or be technically validated."
Then why did you drag up that misguided, facile post from your protégé?
Get a life.
Jeff Medwin
...with TK. The reasoning behind the article you posted is completely wrong. Whatever subjective phenomenon he's describing, that's not the explanation for it.
-Henry
That's a very interesting post and makes perfect sense. But why do I and others who use such amplifiers find that increasing the capacitance of the output stage power supply results in a better more robust bass response, in the context of a circlotron OTL? Granted that the collective Rp of the tubes in an OTL is and has to be much much lower than that of the output tubes in a typical transformer-coupled tube amp. This will somewhat mitigate JLHs dilemma but not entirely. Also, in a circlotron the filter caps are in parallel with the output, I believe. (Can't say I truly understand the circlotron.) Also, shouldn't we be worried about Z at 120Hz, rather than 20Hz or 20kHz? What's flowing into the capacitor would be mostly ripple or DC; yes? Or no?
The lower the internal impedance of your output devices, the less the high capacitance is able to compete with them. OTL and solid state are normally lower voltage, high current topologies and are not as badly effected.
...I would think that an excellent case could be made for concern regarding PS Z at frequencies very much lower than 120Hz or even 20Hz.
Consider music with say a bass drum with a 20Hz resonant frequency being struck at a 1Hz interval. With most amp designs, the PS will have to contend with both 20Hz AND 1Hz. Unless the PS possesses a very low impedance at 1Hz, its output will be modulated at 1Hz regardless of the impedance at higher frequencies. Although it gets into semantics, in my mind a PS with a "fast recovery" almost by definition would be modulated by the 1Hz component and the result would probably be audible in the higher ranges.
Seems that the real question is how best to address the design for a power supply that maintains an acceptably low impedance over frequencies ranging from the infrasonic region to well beyond audibility.
The bit about 120Hz was an aside, really, but thank you for enlightening me.
My main point was how to explain my direct observation of the behavior of a circlotron with respect to capacitance in the filter(s), the more C, the better, deeper, more well-defined the bass. Please don't misconstrue this to mean that I advocate huge capacitors as a general approach to PS design. I bring it up only to find out how my observation (and that of several others) fits with JLHs post as quoted by Jeff, to the effect that large capacitors with attendant very low Z at low frequencies can compete with the output tube for current. The circlotron may be a special case when compared to typical output stages. (Yes, Jeff, I know I am among a small minority who use OTL amplifiers; I can live with that.)
Hi Steve,
I agree with you on resultant frequecies. My first audio mentor, Bob Fulton, was doing a recording at Severence Hall, organ, and he followed frequencies on his o'scope down to 2 Hz, 1 Hz, 1/2 Hz, 1/4 of a HZ.
I disagree with your assertion on fast settling supplies not being good at doing bass, because all of the actual implementations that I have heard (Dennis') and built for myself had superior bass to anything else I have heard with a traditional supply.
I've only heard of one or two reports of inferior bass, and goodness knows what was going on in those instances. Usually, I get feedback of fabulous bass, and from the better audio listeners. This was what I reported up here years ago, when I first built and heard the circuit for myself, on Greg Bradford's Altec 515B / RCA MI-1428 field coil system.
Jeff Medwin
Jeff:
Please note that I attempted to stay out of "judgmental" aspect of a "fast" supply vs something else by the use of the hopefully neutral word "audible". My primary intention was to point out that there is probably more to designing a power supply for music applications than might be obvious. There are many possible approaches to the power supply issue and I'm not inclined to debate them ad infinitum as some here are.
Lew,
Lew,
Good question. I know you are a no-transformer tube amp person.
I simply do not know the answers to your questions. Maybe you should have asked JLH, he is the EE, and I have no such formal training.
A small percentage of the amps made, are of the OTL type you use, and since I don't use them, I really have never concerned myself with what works for OTL type amps.
Cheers,
Jeff Medwin
"I have no such formal training"
So you are not actually a Dr? Just currious, if you oppose formal eudcation, why did you pick a moniker with Dr in it?
Hi,Are you kidding me, nope, I only have a Batchelor of Science degree from Penn State in Business Administration, and part of an MBA.
I used to be a stock and commodity broker in Beverly Hills CA, and I owned a seat on the Kansas City Board of Trade. Now I am in marketing /sales.
Here is the story: In 1986-88 I co-designed with Robert W. Fulton and Bob Goodman, (and personally built) an eight chassis P-P-P 6B4G amp (maybe 500 pounds in weight) which was a laboratory-type amplifier. Everything was double regulated, filaments, B+, maybe 18 regulators. The local Kansas City audiophiles who heard it then were blown away with how it played, and it was THEY who gave me the label that stuck, "Dr. Low Mu".
Jeff
Edits: 03/08/11
The PSU changing the signal asynchronously is a good thing, no.
A more useful endeavor may be to balance the idle currents on the two sides of the P-P OPT primary.
You cannot model it on PSUD2, but, you may hear it ;)
Happy Ears!
Al Marcy
Even "Class A" amps have some variable current demand when the amp is thumpping away at higher outputs, not a lot, grant you.PSU II has a current step function so you do not have to run a simulation twice to see results at different current draws. Nothing in the real world will result in an instantaneous shift in current like PSU II program models. However, if you are just looking to compare two current levels, that doesn't matter. It appears that the step function was designed to look at the "stiffness" or regulation of the power supply in regards to voltage change due to changes in demand. A better regulated supply will have less voltage drop when you increase the current draw.
Most people here are looking at PSU II's step function and counting the time the simulation shows "settling". Fun stuff, but that instant step does not have an analog here on earth. A ringing power supply is a valid concern (look at the "flywheel" oscillator) and setting time is an indication of stability, but you can't base your whole understanding of setting time on PSU II's step function.
___
Long Live Dr.Gizmo
Edits: 03/08/11 03/08/11
Even "Class A" amps have some variable current demand when the amp is thumping away at higher outputs, not a lot, grant you.
Very true.
The topology of a properly designed PS assists Class A.
I Keep the last cap feeding the OPT small with a "properly" sized choke before it.
The last choke provides the stability for transient current demand and the smallest cap one can get away with, provides the speed and recovery.
I try to keep the last cap no greater than 50uf.
> look at the "flywheel" oscillator
The "flywheel" is not an oscillator. The input section is overdamped. IMHO, most of the negative comments posted here talking about current spikes produced by the flywheel are due to either, a) basic misunderstanding of how the circuit works, or, b) misinterpretation of garbage data produced by PSUD.
-Henry
Henry hi,
If the data is garbage, how can it be misinterpreted as anything but garbage?
Mitch
Some people are misinterpreting the nasty spikes that sometimes come out of PSUD as an accurate predictor of real circuit behavior. This is one of those cases where blind faith in the simulator leads you astray.
-Henry
This is one of those cases where blind faith in the simulator leads you astray.
Agree!
But they keep going back to the same flawed postulate and simulator. The amount of time wasted fine tuning this nonsense with PSUD, knowing it will hum, one could have (I did) bread boarded and fine tuned an amps PS with custom chokes and motor runs, listened and o'socped it - dead quiet. The thread is still going on.
I guess the rest of us need to accept traditional, proven and quiet PS design is unruly.
Repeatedly slamming ones head against the wall and expecting a different outcome.....
Mitch
To clearly answer your question :
It can be interpreted from what Henry has shown us all on his o-scope shots Mitch, that garbage, (PSUD II artifacts Henry calls it), does not exist on his scope.
Jeff Medwin
Nor does it exist if a more sophisticated simulator is used.
PSUD2 is very good as far as it goes but we shouldn't expect too much of it. If we want a more complete simulation picture there are other tools, which many members already use, e.g. LTspice. This SW is free and not too difficult to use IMHO. I wouldn't be without it!
Hello,
Nicely said op48no1.
I also agree that class A1 is hardly as "constant" as people think it may be.
None of the thoughtfully-designed supplies ring. Of course, what some DIYers may "kluge together" can ring, with an equal proclivity in a traditional supply, or in a modern supply.
John Swenson is the Forum Member who did all the work, and posted it up here, on settling time. He actually did measurements of music, and subjective listening, and he found a very close corelation between the two (versus settling time), and how it sounded to him on his Lowther speaker rig, (a good audio system).
It is best to go back, download all his posts in chronological order, and carefully read about this, because this is ALL we have ever seen (on this Forum), about the need for a certain settle time, corelating it to music measurement, and to subjective listening tests.
If Forum Members want to have the complete chronological posts of John Swenson sent to them, I can privately email them to anyone who asks. Until I see someone do similar work at an equal or higher level, I would tend to take John's measurement work at face value.
It beats just "guessing" at the subject. Cheers.
Jeff Medwin
"I would tend to take John's measurement work at face value."
The three categories of evidence are OBJECTIVE (scientific measurements), SUBJECTIVE (scientifically conducted, i.e. 'double blind,' listening evaluations) and BULLCHIT (unscientific listening tests followed by unsubstantiated pronouncements). Into which category do you think your work and the similarly processed work of others falls?
--------------------------
Buy Chinese. Bury freedom.
and number 3 is rarely on the list.
That is the single thing that has kept me out of this arena on a professional basis in order to make money to support myself.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
My work, and John Swenson's work, I would say is in category one and two and of benefit to the audio art. You are way off-base to attack my post in such a mean-spirited way, and it a reflects, at least to me, (along with your post above "Capacitance") just how desperate you are.This should be a positive Forum, and you "flaming me" is not a positive way to conduct yourself.
Jeff Medwin
Edits: 03/08/11
Categories of evidence
Unscientific listening tests followed by unsubstantiated pronouncements
I wouldn't consider the above substantive or a category....other than BullChit.
I am not in a position to comment on the posting but I would like to ask, "Why does audio have to be scientific? Why can't it be that on paper it might not work but if built, it might?
I have a close friend who is an HVAC engineer and he is more than capable of designing an HVAC system for any building ever made and probably ever will be made. Being an engineer he is very scientific and mathematical, like all engineers. It all has to make sense on paper before it goes out to be built. That is the thinking of him and any other egineer I ever met. I asked him once the design is drawn up and approved are there any changes that ever need to be made once the job is being done. More often not, but yes, at times. Couldn't this just be one of those times.
According to others that posted about the PSUD program, from what I understand it is a place to get going with a supply. if it comes that it is totally correct and all is good, then so be it. But there has to be times when the ear is a better tool than the program.
I hate to say it but my friend is a well known builder of speakers(mainly a cabinet maker) and uses crossover designs that is made on computer for him. The speaker is never listened to beofre he gets the design back to copy. His crossover builder(won't give any names) doesn't even listen to his work. He sends it back and says this is what it is supposed to be built and that is that. Many times I have listened to some of his new designs and to me they are always too bright. They maybe flat on a computer but in the real world to me, not so! Room conditions, ability to hear correctly(age factor), the recording itself, and of course, the other components used, all play a factor.
Programs are nice but so is the ear!
----Being an engineer he is very scientific and mathematical, like all engineers.
Not a reasonable conclusion IMO/IME.
----It all has to make sense on paper before it goes out to be built.
Now that comes closer to my experience. Practice deviates from that scenario on proof-of-concept implementations where detailed funding for such projects is controlled by the engineer and his craftsmen.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
According to others that posted about the PSUD program, from what I understand it is a place to get going with a supply. if it comes that it is totally correct and all is good, then so be it. But there has to be times when the ear is a better tool than the program.
Very well put, it's a starting point or tool!
After that, the bread boarding begins and values get fine tuned. When it sounds good, the sweeps begin and possibly more fine tuning.
Of course there are certain parameters that should be followed with C1. Albeit, SS rectifier or tube rectifier.
I keep a good stash of motor runs in varying uf and chokes on hand.
I too keep a good stash but I have no idea what to do with what and who to make anything do something different. I know that statement is hard to understand but I got into the JLH and Jeff Medwin theory of the "less is better!" I would have to say what I did build(now has changed because of hum but Jeff did warn me that might happen with triodes) was in that theory and I liked what I was hearing, thus my original supply was either terrible or the newer "less is better" supply is the way to go if you can get it quiet. I am now down to a smaller cap on the rectifier, then a 4H choke, then a little bit larger cap then another 4H choke with a larger cap. It is now quiet and sounds good. All caps are either motor run or poly.
But if anyone remembers the statement Mike Samra always signed off with a while back. He stated' "If the wave form is good then it will sound good!" I never really looked into it but I do remember a couple of amps my friend worked on in the past where it measured terrible(according to him) but sounded great, according to me. I actually listened to a terrible measuring amp on a couple of different occasions and I liked what I heard. My friend even went as far as changing the amp for the measurements to be better or more correct and it started sounding worse and worse, as an experiment. He ultimately put it back to original.
I also remember when this engineer from Lafayette products built an amp just on measurements with scopes and meters. It was awful sounding but it measured accurate for the tubes he used. From some suggestions he tried other things and it got to sound the way music should but on the same token, the measurements were way off. Go figure!
What I am trying to say is that things need to be voiced and other things need to be tried before comments of any substantiation can be used.
But at the end of this I do feel everyone is entitled to voice their thoughts without being beaten up verbally. We can all agree to disagree if that's what it takes but the name calling is uncalled for.
Paul
A good stash of chokes, would mean the proper "H" based on the current it sees, as called for in the Hanna chart.
Mikey's signature line:" if the PS waveform.......
The power supply waveform is DC, which is a straight line. 0Hz, no waveform!
We can all agree to disagree if that's what it takes but the name calling is uncalled for.
Sometimes statements/claims are made without anything to back them up and defies logic.
"less is better" supply is the way to go if you can get it quiet.
Then it's not properly designed, passing ripple and causing other issues.
Wheezer,
Unless people read my full statements that you took quotes from, the context of what I am saying is missing. I think thew entire quote should be stated.
I remember Fox News did that to something Hilary Clinton stated and they left out some of the pertinence of the quotes so she would come out a loser on the issue. I heard the entire interview and although the Clintons or the Obamas aren't of my favorite to run a country, I did have to give her the benefit of the doubt because she was very articulate in what she was trying to get across.
I am not say that's what you are trying to do but if the entire quote isn't stated people can get that impression.
Paul
""I remember Fox News did that to something Hilary Clinton stated and they left out some of the pertinence of the quotes so she would come out a loser on the issue. I heard the entire interview and although the Clintons or the Obamas aren't of my favorite to run a country, I did have to give her the benefit of the doubt because she was very articulate in what she was trying to get across.""
Speaking of leaving out pertinent information to make Fox News look like they lack integrity, just what quotes did they leave out that made Hillary look like a loser on the issue?
Or I will start to tell you how I feel about Fox News and their ilk.
It's common knowledge that liberals and their ilk have little regard for the truth, so I would ask that you go back and carefully reread the xaudiom post and you'll see that he was the one that brought politics into the discussion, not me, so instead of chastising me get a clue and chastise the originator of the political rhetoric.
And by the way, liberals can't defend their deplorable ideology with sound reasoning and logic, so you don't even want to get into a discussion with me about Fox News and their ilk.
I hate to bother the moderator, but this subthread deserves to be terminated with extreme prejudice, as it were.
-Henry
I doubt the mods would feel inclined to act with such severity unless there are ad hominem attacks or other blatant rule violations.
IMHO, we've crossed the line on both counts. YMMV.
-Henry
Oh, I don't know. This forum is pretty mild compared with some others. Ever had a look at Critics' (Critters') Corner, for example?
Based on a brief email conversation I had with Mr. Diode, I don't expect the world would have much to lose if this topic were to continue without him.
-Henry
And that's what I wrote the first time.
It's a mystery to me why, when an individual brings partisan politics into a discussion like Xanaxmanx did, and somebody responds to it, the responder gets blamed for creating the problem.
It's really very simple... don't bring politics into the discussion in the first place and there won't be situations like this one.
Paul,
Good points you bring up. Plus, Mitch does not have a good grasp of the supply, so it is misinformation he spouts. Witness this diddy:
"Then it's not properly designed, passing ripple and causing other issues."
Q1) What exactly does "properly" designed mean?
Q2) EVERY supply passes ripple, the question is, how much is tolerable?
Q3) What other "issues" does Mitch perceive?
Q4) Does he understand that the supply is located throughout the amp, and the amp as a total entity must be looked at? NO, he certainly does not.
Jeff Medwin
So, it is not a resonant circuit?Also "misinterpretation of garbage data produced by PSUD" agree, and that was the main thrust of the response to PSU II "Settling".
___
Long Live Dr.Gizmo
Edits: 03/08/11
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