This is simply too sad to laugh it off...
Almost a hundred years of electronics knowledge which brought us from spark telegraphs to 4K television transmitted via geostationary satellites.
And this plentiful knowledge is all simply brushed off by self-declared experts with golden ears. Basic electronic principles are declared to be no longer valid just because someone is tricked into believing his circuit sounds so much better. And instead of being happy with it, others need to believe it too, otherwise they do not know anything about electronics.
I would be ashamed to tell beginners "not to listen" to well-educated scientists and electronics engineers and "believe" my ears instead. But shame or self-reflection is usually not one of the strongest traits in such personalities.
@DF86: I really appreciate your efforts to help beginners and advanced DIY people with your knowledge. Thanks for trying again and again, although threads like this happen more and more often.
Regards,
Rundmaus
Almost a hundred years of electronics knowledge which brought us from spark telegraphs to 4K television transmitted via geostationary satellites.
And this plentiful knowledge is all simply brushed off by self-declared experts with golden ears. Basic electronic principles are declared to be no longer valid just because someone is tricked into believing his circuit sounds so much better. And instead of being happy with it, others need to believe it too, otherwise they do not know anything about electronics.
I would be ashamed to tell beginners "not to listen" to well-educated scientists and electronics engineers and "believe" my ears instead. But shame or self-reflection is usually not one of the strongest traits in such personalities.
@DF86: I really appreciate your efforts to help beginners and advanced DIY people with your knowledge. Thanks for trying again and again, although threads like this happen more and more often.
Regards,
Rundmaus
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Sorry, I' m not planning to build the particular amplifier so the designing approach is beyond my interests. My question was more general and I think I have my answer after some reading about NFB.
I should think twice before posting in this thread... Certainly, I' m not in position to say if this amp sounds good or bad and I would accept that nobody can say unless he listens to it. But I can't disregard experts in the forum! They have the knowledge and willingness to advise for any given task and not just study cases.
Well, my personal SET uses enormous electrolytic capacitors and very large chokes. I cannot complain for a lack of dynamics. I made my amp to sound with hair rising attacks and very good microdetail. I'm not trying to boast, but I say this because I dislike stereotypical thinking and authoritative talking when it comes to diy audio. There are many ways to build a good product.
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I chose to leave AA because of the ad nauseam religious claims of Jeff Medwin. Unsubstantiated, completely contrary to sound engineering, and generally non sensible. Sad to see he has come here and polluted this forum with the same garbage. But alas, it's a free country, so you will have the few cult members who choose to give him ear, as they believe he hears from god (or has god's ears) and that the advice actually has value. Those postings will also be replied to by a few that think there is value in trying to teach him some basic scientific truths. They mean well, but don't understand how entrenched in delusion he truly is.
Those who understand how electronics work know better. You are only fooling a select few, lowmu. Feel free to keep trying; I guess I just need to sit back and chuckle at the folly that comes next. This is just the beginning, poke the religious bear and see what comes next. "ignorant engineers", "never tried it", "Robert Fulton said" blah blah blah.
Those who understand how electronics work know better. You are only fooling a select few, lowmu. Feel free to keep trying; I guess I just need to sit back and chuckle at the folly that comes next. This is just the beginning, poke the religious bear and see what comes next. "ignorant engineers", "never tried it", "Robert Fulton said" blah blah blah.
Why do you repeat this error? I have explained how small caps and no NFB result in dynamic distortion. Now if you want to call envelope distortion "dynamic capability" then so be it, but at least admit that this is a step away from fidelity. It is the cap which provides the instantaneous energy, so the truth is exactly opposite to your misguided advice.drlowmu said:
Possessing an EE degree does not make bad advice good. Those with EE degrees (or any other good education) should know this.
Yes, when designing electronics don't worry about boring stuff like circuit theory based on sound physics. Just follow the recipes advocated by gurus.
It was the popularity of such stuff over there which caused me not to join that forum, and eventually to rarely visit it - except when I needed some amusement. At least here we can all be reasonably certain than nonsense will be corrected; sometimes people try to 'correct' truth too!zigzagflux said:
I have explained why using small caps for a typical SET amp can give the false impression of better dynamics; you get false dynamics, which I suppose some people may prefer so for them it is 'better'. If you prefer hi-fi but still want to use SET then follow this advice:
50AE said:
Guys
I will not throw away drlowmu-(Jeff) claims easy just like that , since I have impression that Jeff have huge experience doing DIY SET amps for decades , specifically with those Loftin-White type ,so let`s allow that hi maybe talk about some very specific positive optimum solutions but sometime just using wrong and non-EE expression language .
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one question for Jeff , do you have try to implement those very fast photo-flash electrolytic capacitors for your SET-PSU ever ?
I will not throw away drlowmu-(Jeff) claims easy just like that , since I have impression that Jeff have huge experience doing DIY SET amps for decades , specifically with those Loftin-White type ,so let`s allow that hi maybe talk about some very specific positive optimum solutions but sometime just using wrong and non-EE expression language .
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one question for Jeff , do you have try to implement those very fast photo-flash electrolytic capacitors for your SET-PSU ever ?
I think that in audio all opinions have their true, is good for me but maybe not for you. In the scope you see and measure but the ears con not compare with any scientific instrument 🙂
Airtight or Audio Note UK use big electrolytic capacitor, with very good sound
Shindo or Thomas Mayer use very small oil capacitor, with very good sound
two of my friends who have listened both prefer small oil cap with more chokes steps, but who knows...
Airtight or Audio Note UK use big electrolytic capacitor, with very good sound
Shindo or Thomas Mayer use very small oil capacitor, with very good sound
two of my friends who have listened both prefer small oil cap with more chokes steps, but who knows...
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Experience is not a substitute for knowledge and understanding; ideally it leads to them, but this is not guaranteed. There are a number of people on this forum (and even more elsewhere) who have been making DIY amps for a long time (or selling commercial amps) yet who still seem to stumble over basic circuit theory or related issues (e.g. Fourier denial).banat said:
No. He is not expressing a correct idea using wrong language. He is explicitly rejecting a correct idea, even after an explanation has been offered.
You are free to think that, but it is untrue. Opinions about facts are either true or untrue, because none of us has his own private universe with his own version of physics. We can have our own preferences about sound, and which distortions we prefer or wish to avoid, but that is a quite different matter.Celsius said:
True. Instruments are much better at telling us what is. Ears are much better at telling us what we prefer. Problems occur when people get these two different issues mixed up.
The key word is "prefer".
I actually admire Drlowmu's designs. Mainly because the stuff he applies goes back to the old school of thoughts way before electron flow theory. Back when I started learning electronics 30 years ago.
btw people call me an "old school" builder. But that is mostly because I wire point to point.
I will sign out of the thread before I get binned. DF96, I admire your attempts to correct. When lowmu is involved, my experience has shown that you are wasting your time. We already have a few religious followers who are prepared to drink the Kool-aid.
Show someone geologic proof that the earth is billions of years old, and one chooses to hold on to his book that says it's 6000. And admires himself for such devotion in the process. We rightly reject religious discussions on this forum, yet allow it to infiltrate in the name of so-called open mindedness.
Show someone geologic proof that the earth is billions of years old, and one chooses to hold on to his book that says it's 6000. And admires himself for such devotion in the process. We rightly reject religious discussions on this forum, yet allow it to infiltrate in the name of so-called open mindedness.
lol ,well its not "rob" really but it has to do with discharge efficiency and recovery of the power caps.
But the difference in thought with his and the classic power supplies is "maximum transfer of energy" instead of "virtual battery" that is the train of thought used in semiconductor based designing.
When I started learning electronics nearly 50 years ago I think 'electrons are negative' was already well established. A little Googling will find crackpot sites where 'electron flow theory' is criticised by people who don't understand physics; I assume this is not what you are referring to? What are you referring to?DavesNotHere said:
I think he said "rob". He seems to imagine that the amp gets its supply from the rectifier via the choke, and the capacitor is just there to reduce the ripple a bit by stealing the supply. In reality the capacitor is the amp supply for much of the mains AC cycle; once again the truth is the opposite of what he says. Small caps will recover more quickly, but they will also sag more so have greater need to recover. A sagging PSU may be fine for a guitar amp, but a guitar amp is part of a musical instrument so quite different from a music reproducer.
People who design with semiconductors (and valves) need to use the appropriate physical model. Valves and semiconductors use the same circuit theory, as they exist in the same universe with the same laws of physics. Using the wrong model is not a sign of greater wisdom and sophistication.
There really isn't right or wrong models. Only right and wrong applications with models.
If I built a circuit that has an infinite power supply rejection would it need to be in a low ripple supply. By experience, no.
My first teacher was an retired RCA EE that I worked for in his tv repair shop. So that is why I learned the old hole theory stuff.
There was only a few terms that are differently said but most is the same. It just how you word it to other people changed. Formulas didn't.
DF96
-Do you really think that Only people who perfectly understand and implement any known circuit theory are Only capable to made good sounding hi-fi audio equipment but nobody else ?
-Well , Jeff `s freedom is chance to choose which idea is personally correct and good for him and which idea is not correct and good , regardless from your idea , mine or anybody else ideas .
-btw , IMHO one of the many problems with those SET amps is that they usually measure relative pretty bad but sounds relatively good ,
and yes , just to be clear personally I was never big fun of those SET amps .
I disagree. There are lots of wrong models, some misapplied models, and a few good models. A good model will lead you to make good design choices, such as correct value for PSU caps. A bad model will lead you astray.DavesNotHere said:
Agreed. Theory and experience say the same. Correct theory and properly understood experience will always say the same.
Nothing to do with the issue in this thread, which is how small caps make the rail voltage vary with signal envelope and most SET amps vary their gain with rail voltage - hence gain varies with signal envelope, which is bad if reproduction is your aim.
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