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Another silly question
Another silly question
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Old 17th September 2019, 02:38 PM   #51
DF96 is offline DF96  England
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Quote:
Originally Posted by N101N
maybe I should start parroting the standard opinion learned through rote memorization.
If you cannot tell the difference between understanding and "rote memorization" then you are more ignorant than we thought.

Quote:
It would also shrink my self-importance.
This would be helpful to us all. It would even help you.

Quote:
I have said that Classical Physics is incapable of describing and explaining even the most basal aspects of the audio field. Everything happens at a subatomic / molecular level and it is compulsory to go that deep.
No. People who cannot understand science even at just a superficial level often try to hide this by claiming that something deeper is needed.

Quote:
For clarity, I have not said that Control Theory is flawed. I have said that Control Theory has no relevance to audio. Control Theory is a simple theory meant for a simple task. Audio is complex and entirely different.
No. The task of an audio amplifier is quite simple: amplify a time-varying bandwidth-limited voltage with a reasonable degree of fidelity. Control theory is quite adequate for this task. Problems occur because too few audio designers understand control/feedback theory. Some try to hide this by claiming that something "deeper" is needed.

In order to abandon classical physics you first have to embrace it. We have seen no evidence of this in your posts thus far.
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Old 17th September 2019, 02:44 PM   #52
cumbb is offline cumbb
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Everything that happens in the few micrometers of a cicuit is served in cubic meters.
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Old 17th September 2019, 03:33 PM   #53
GoatGuy is offline GoatGuy  United States
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Oh​​​ {for​​​ upvotes},​​​ maybe​​​ I​​​ should​​​ parrot​​​ standard​​​ opinion​​​ learned​​​ through​​​ rote​​​ memorization.​​​ It​​​ would​​​ also​​​ shrink​​​ my​​​ self-importance.
N101N … because you're persistent, and because I trust that you are honorable, let me see if I can engage you to move past the epistemilogical¹ and into actually discussing and perhaps being enlightened by some of the non-standard theory to which you repeatedly extol. Care to move from the didactic² to the concrete?

Quote:
...​​​ I​​​ have​​​ said​​​ that​​​ Classical​​​ Physics​​​ is​​​ incapable​​​ of​​​ describing​​​ and​​​ explaining​​​ even​​​ the​​​ most​​​ basal​​​ aspects​​​ of​​​ the​​​ audio​​​ field.​​​ Everything​​​ happens​​​ at​​​ a​​​ subatomic​​​ /​​​ molecular​​​ level​​​ and​​​ it​​​ is​​​ compulsory​​​ to​​​ go​​​ that​​​ deep.
This seems to be your central thesis.

That contemporary physics and its finding (and mathmatical formalism) of the idea that sound is a varying-over-time train of higher and lower pressure wavelets in the medium we call “air”, that contemporary physics' misses what “the audio field” really has to say about acoustics, sound reproduction and so forth from there.

Yet in turn, just following the dots, there must be an unconventional theory that can step in to embolden our understanding of the thusly-enlightened points of discourse to which you necessarily have come to embrace.

Right? So far lad as DF96, I and others have critiqued, your comments haven't yet included even a scintilla⁵ of the connective words-and-phrases that would be that alternatitive — and to honor your point … better — descriptive matrix more accurately quantifying acoustics and 'audio' as a whole. So … start! already! Move onto talking about it!

Quote:
I​​​ have​​​ not​​​ said​​​ that​​​ Control​​​ Theory​​​ is​​​ flawed.​​​ I​​​ have​​​ said​​​ that​​​ Control​​​ Theory​​​ has​​​ no​​​ relevance​​​ to​​​ audio.​​​ Control​​​ Theory​​​ is​​​ a​​​ simple​​​ theory​​​ meant​​​ for​​​ a​​​ simple​​​ task.​​​ Audio​​​ is​​​ complex​​​ and​​​ entirely​​​ different.
Methinks that you had a most unpleasant experience with embracing engineering's most cherished chestnut: control theory. It is understandable, N. Tho' you panned CT as “simple” (it is anything but), and further that CT finds applicability only to “simple tasks” (mostly true, but only because most tasks are simple… it also rises to far, far more complex tasks too!), it might still be the case that your understanding of its mathematical formalisms is incomplete.

So, let's put Control Theory behind us for the rest of this discussion. In so doing, some of us — and at least I in particular — now become 'blank slates' onto which you might inscribe the runes of the alternative to classical physics' acoustic and electronic circuit theories. Will you agree to this?

Quote:
I​​​ am​​​ not​​​ comparing​​​ Classical​​​ Physics​​​ to​​​ the​​​ Voodoo​​​ religion​​​ but​​​ to​​​ other​​​ branches​​​ of​​​ established​​​ science.
OK. It is true that one really cannot compare physics to say biology, or psychology, or archaeology³. But insofar as further discussion goes, I think it incumbent on you to now prepare a modest reveal, N. There's no point repeating your opinion as to how inadequate contemporary physics is in guiding a designer's hand in crafting the circuits and devices that we employ to amplify and reproduce recorded sound. No.

The rally is moving on to as-yet-uncharted territory. My invitation is to you, for you to now reveal and expound on what you have learned. It'll take some courage: most denizens of good character here will likely find the alternate theories abrading to their long held mathematical and topolotical understanding of circuits, circuit-theory and so forth. There will be push back. But that is where we need to go next.

Or to put it in tennis terms, its a fresh set, its your serve, and you've got at least 1 player willing to return the volley.

Just saying,
GoatGuy ✓
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¹ epistemological … theory of beliefs, especially with regard to distinguishing between methods and scope.

² didactic … method of teaching, rooted first in moral and ethical grounding

³ archaeology … archaic spelling

⁴ {redacted}

scintilla … from greek, “tiniest spark”; a tiny corner of a larger picture.
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Old 17th September 2019, 10:11 PM   #54
GoatGuy is offline GoatGuy  United States
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Quote:
Originally Posted by bobberner View Post
How difficult is it to design an amplifier?
To design an amplifier … pretty easy.
To design a good amplifier … more challenging.
To design an excellent amplifier … requires years of experience.
To design an excellent, feature-fill amplifier … is what multi-million dollar companies do.

Quote:
Originally Posted by bobberner View Post
I've been looking at plate amplifiers at Parts Express. There seems to be a void in a feature rich 2.1 BT plate amplifier. I'm thinking of something with moderate power, smallish size, BT, and perhaps WiFi (though I don't know how that works) along with 5V usb out to charge a phone, or even take audio signal via the USB while charging.
That turns out to be a list of criteria that have very little to do with the amplifier per se, and much more to do with packaging and feature-cruft¹ inclusion. Which is OK, Bob.

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Originally Posted by bobberner View Post
It doesn't have to be a plate amplifier either. I do like the fact that plate amps do take up any real estate and if you really need any LEDs or indicators they could be mounted remote from the plate, like on the front or top of the cabinet.
Be wary, Bob. Class-D amplifiers are the only kind that have average (and maximum) power dissipation low enough to work in fanless … and even vent-less configurations supporting your attraction. All the rest, the so-called “linear amplifiers”, require substantial heat wicking and dissipation in order to work for more than a few seconds near highest power. So, there you are.

Quote:
Originally Posted by bobberner View Post
This could almost be put together from existing off the shelf parts. there is a lot of inexpensive and probably crâhppy little things out there, and there is expensive high end stuff. Isn't there a market for mid budget quality components?
EBay is full of pretty inexpensive modular parts Bob. You can create a smallish Class D amplifier and power supply from commonly available parts probably for less than $150 all in. Minus the speaker, of course. If that's what you are looking for, then its done. If you are looking for something more exotic …
Then you need to spell out what the parameters are, that you are looking to implement
Just saying,
GoatGuy ✓

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^ cruft - a delightful word from the computer science community to somewhat disparagingly describe all the 'stuff' which seems to infest what once was tight, concise, elegant code. This is not to say that cruft is bad, or unwise, or even necessarily inelegant. Just that it is a “egg crate box, taped to the side, with wires hanging out” sort of approach.
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Old 20th September 2019, 06:40 PM   #55
zjjwwa is online now zjjwwa  Poland
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Another silly question
Quick question:
Which of the two presented rectification schemes for a symmetrical rails PSU is better?
The left one or the right one?
I am not concerned about the cost of the additional rectifier bridge in one of them.
I am not concerned about the slight voltage difference on the output of the two scenarios.
How do these architectures differ in terms of overall performance, parameters, pro's and con's, side effects?
In which of the architectures will the transformer produce less audible hum?
Many kind thanks for your valued inputs.
Does any of the two constitute a "better fit" for a: 1). Class A amplifier, 2). Class AB amplifier, 3). Class B amplifier?
Attached Images
File Type: jpg Which PSU architecture better.jpg (70.8 KB, 88 views)

Last edited by zjjwwa; 20th September 2019 at 06:45 PM.
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Old 20th September 2019, 07:52 PM   #56
GoatGuy is offline GoatGuy  United States
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The left topology, I prefer. It puts lower demands in both total power dissipation and peak reverse voltage blocking on the diodes of the bridges. It also isolates positive-rail surges from having negative-rail blow-back and vice versa. Its marginal additional cost is small, except when the double secondary winding transformer is itself often quite a bit more expensive than a single output transformer, with a center-tap (electrically the same as the RIGHT topology).

Just saying,
GoatGuy ✓
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Old 20th September 2019, 08:07 PM   #57
zjjwwa is online now zjjwwa  Poland
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Another silly question
Quote:
Originally Posted by GoatGuy View Post
The left topology, I prefer...
Thank you for your opinion on this.
>>>It puts lower demands in both total power dissipation and peak reverse voltage blocking on the diodes of the bridges.
Agreed.
>>> It also isolates positive-rail surges from having negative-rail blow-back and vice versa.
So if I understand correctly, this would be especially important in the case of class AB amplifiers, yes?

>>> double secondary winding transformer is itself often quite a bit more expensive than a single output transformer, with a center-tap (electrically the same as the RIGHT topology).

Let's take this concept yet a little bit more expensive. What is better, a single core toroidal with two sets of secondary windings, or a sibling pair of two toroidals, one "on top" of the other (co-axial), on the same mounting bolt, whereby the magnetic flux generated by the primary of the lower toroidal is in opposing direction (anti-phase) of the magnetic flux as generated in the primary of the upper toroidal ("opposing flux directions")?
I once was fooling around with two chokes. Matched, identical chokes. Each having 1 Henry inductance. Wired them in (anti-phase-)series with each other, tied their cores strictly together, and received the following result:
1,0 + 1,0 = 2,2.
Maybe such concept of opposing fluxes as in a toroidal "double-decker" will also provide some incremental benefit? Better magnetic coupling, or something?

Last edited by zjjwwa; 20th September 2019 at 08:10 PM.
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Old 20th September 2019, 10:07 PM   #58
bobberner is offline bobberner  United States
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Another silly question
Quote:
Originally Posted by GoatGuy View Post
To design an amplifier … pretty easy.
To design a good amplifier … more challenging.
To design an excellent amplifier … requires years of experience.
To design an excellent, feature-fill amplifier … is what multi-million dollar companies do.



That turns out to be a list of criteria that have very little to do with the amplifier per se, and much more to do with packaging and feature-cruft¹ inclusion. Which is OK, Bob.



Be wary, Bob. Class-D amplifiers are the only kind that have average (and maximum) power dissipation low enough to work in fanless … and even vent-less configurations supporting your attraction. All the rest, the so-called “linear amplifiers”, require substantial heat wicking and dissipation in order to work for more than a few seconds near highest power. So, there you are.



EBay is full of pretty inexpensive modular parts Bob. You can create a smallish Class D amplifier and power supply from commonly available parts probably for less than $150 all in. Minus the speaker, of course. If that's what you are looking for, then its done. If you are looking for something more exotic …
Then you need to spell out what the parameters are, that you are looking to implement
Just saying,
GoatGuy ✓

________________________________________

^ cruft - a delightful word from the computer science community to somewhat disparagingly describe all the 'stuff' which seems to infest what once was tight, concise, elegant code. This is not to say that cruft is bad, or unwise, or even necessarily inelegant. Just that it is a “egg crate box, taped to the side, with wires hanging out” sort of approach.

Thanks GoatGuy,

I guess I phrased my question poorly. And May have offended some of the forum because of that. I guess that with the prevalence, dare I say ubiquity, of Bluetooth, why isn't it included with things that would benefit from having it rather than making it an external add on? Same with USB charging ports.

I've used the Dayton Audio BT amp boards in two small speakers. They recently came out with a mounting plate that holds all of the LEDs, switches, etc. but didn't add usb. Seems like that would be a no brainer.

So often I see products that almost get the features/interface right, but yet just fall short of being ideal. And it isn't always simple to cobble stuff together neatly. That was what I was kind of getting at.
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Old 21st September 2019, 04:35 PM   #59
DF96 is offline DF96  England
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Why would an audio amplifier need a USB charging point? I can understand that some might want a USB audio interface, but what is the use of a charging point when most people have loads of these in their house already? Why not add a clock, and a calendar, and a small TV screen too?
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Old 23rd September 2019, 12:30 PM   #60
N101N is offline N101N
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Quote:
The task of an audio amplifier is quite simple: amplify a time-varying bandwidth-limited voltage with a reasonable degree of fidelity.
Meaningless semantic jargon that the previously cited papers and popular textbooks are filled with. Any change occurs in both space and time, all magnitudes having a limit. "Reasonable degree" is a worthless definition as well.

Quote:
No. People who cannot understand science even at just a superficial level often try to hide this by claiming that something deeper is needed.
Profound science is for the stupid ? Looking below the surface requires improved investigation techniques, Ohm's law won`t get you anywhere.

GoatGuy,
Control Theory is just a bunch of guidelines for an efficient voltage regulator using preexistent knowledge. The epithet "theory" is a misnomer. I don`t think that audio amplifiers should have the characteristics of voltage regulator or utilize harmful voltage regulators. What is an advantage to industrial electronics, where signal handling is a nonissue, is a disadvantage to audio amplifiers.

I am aware of the necessity of offering a detailed presentation.

cumbb,
I agree if you mean that cubic rather than quadratic averaging is closer to the truth. I generally agree with you. You may possess something called an "innate sense". Very rare. Jean Hiraga had it. But you are wrong about the balanced electronic state.

You and I will never be popular, on the other hand, we are not selling anything so...
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