john curl said:
Okay, how about this example. Take a bipolar class AB output stage. We know that it's going to have complex, higher-order distortion to start with by its very nature. Now suppose that a single bipolar driver stage is provided. That will make a somwhat nasty non-linear load for the VAS. Adding another driver stage will reduce the non-linear loading on the VAS and likely decrease the total distortion. Yet all the high-order stuff was already there due to the very nature of the class AB output stage. So in that case, I would think the added complexity would reduce the distortion without adding significant higher-order stuff. I'll bet you'd suggest using a FET as the driver though.
Hi,
Not on my part...Neither I think on Andy_Cs'...
Generally, yes.
Most people don't understand the concept of the content of distortion: to them it's a figure of merit.
The less the better.
We can't really blame them for that as the entire industry has been preaching this "lower distortion equates better performance" dogma for decades in a row.
Same thing for higher wattage really, the more the merrier...But that's another story.
Same thing for an awful lot of things that would require a tremendous amount of "unlearning" by any audio designer worthy of the title.
Weren't we all taught that a capicitor is just C (and nothing else)
or, for that matter, a resistor just R...and so on...ad nauseam.
Ultimately that would still very much depend on the predominating content of that measured distortion.
Although far less complex in content it may not be that easy on the ear to live with as you put it if that content is based mainly on odd order harmonics.
In which case 5% of THD will certainly be audible and far from pleasant either.
Even order harmonics distortion OTOH will add some richness to the sound (warmth as we'd call it) which may be pleasant sounding and easy to live with.
I assume the trick is to find the proper balance somewhere along the distorted line....
Cheers,
Not on my part...Neither I think on Andy_Cs'...
Generally, yes.
Most people don't understand the concept of the content of distortion: to them it's a figure of merit.
The less the better.
We can't really blame them for that as the entire industry has been preaching this "lower distortion equates better performance" dogma for decades in a row.
Same thing for higher wattage really, the more the merrier...But that's another story.
Same thing for an awful lot of things that would require a tremendous amount of "unlearning" by any audio designer worthy of the title.
Weren't we all taught that a capicitor is just C (and nothing else)
or, for that matter, a resistor just R...and so on...ad nauseam.
Ultimately that would still very much depend on the predominating content of that measured distortion.
Although far less complex in content it may not be that easy on the ear to live with as you put it if that content is based mainly on odd order harmonics.
In which case 5% of THD will certainly be audible and far from pleasant either.
Even order harmonics distortion OTOH will add some richness to the sound (warmth as we'd call it) which may be pleasant sounding and easy to live with.
I assume the trick is to find the proper balance somewhere along the distorted line....
Cheers,
But aren't the high-end designers are the stubborn ones? You wouldnt want to use NP's cct even if you know it. Well, there is a thinking coming from mass product imitator, (like ones from China, sorry), not from the fellow high-end designer.
But they always never ended succesfully, just make original designer more famous.
QSC, Crest put all their cct in their website. Has anyone seen imitation QSC or imitation Crest?
Mr.Curl, why dont you makes small single articles like NP? A bunch of this would have make a book already. What is your website?
I'm always amused when people beg Nelson to 'write a book' on audio design.
Just what the hell do you think the man's been doing for the last umpteen years?
Go add the Citation mods, the 40 and 75 watters, the Zen series and such together, sit down, and read. What's wrong? Not enough formulas? It's not the formulas that count, silly, it's the creativity that went into putting the circuit together in the first place. Go get the formulas out of H&H.
Early in my writing career, I ran across the saying that writing can be learned, but it can't be taught. That is to say, you can put in all the gunk about where commas go, and dingly participles, and gerunds whirling in little wheels in their cages, but the missing ingredient--the one that can't be taught--is creativity. The sad fact is that 99% of people ain't got it, never will. The other 1% are the ones who change the world. The ability to sit down with a calculator or a simulation program and come up with a functional amp is not creativity. It's mid-fi. Scads of mid-fi circuits hit the market every year. They work. They sell a few units. Then they're replaced by a circuit that's different, yet the same. Another grad student used his calculator and came up with yet another uninspired circuit that makes sound, but not music. The landfills are full of 'em.
The thing Nelson, John, Demian, Charles, and others on their level bring to the table is the creative ability to go beyond the merely functional circuit and come up with something that has a tiny touch of magic. The extra something that the numbers-uber-alles crowd deride as nonexistant. By their standards, audio has been 'perfect' for twenty or thirty years now. Further attempts at improvement are misguided. They're an ironic kind of high-tech Luddite, wanting to hold the world back in a futile quest for more zeros. Most people got beyond that by the mid to late '70s.
John has been kind enough to drop in here and comment on the (admittedly few) circuits of his that have made their way to the web. The balance of his circuits is different from Nelson's. Does that make either of them wrong? No, of course not. Salt does not make pepper wrong. They're both useful in the right time and place and sometimes taste even better when used together.
So far, I've only seen one circuit of Charles Hansen's (the prototype no feedback amp he posted), but I like the looks of it. Again, does he in any way invalidate Nelson or John? No. Our range, our palette if you will, of design options increased by one when Charles offered his schematic.
There is no one way to design an amp, any more than there's a "most beautiful woman in the world." When I was younger, I used to think that there was a "most beautiful woman." (Either Raquel Welch or Sophia Loren, depending on my mood, though right there were sown the seeds of future enlightenment.) As I got older, I came to realize that there were many beautiful women. A little further down the path, I realized that a large part of what made the woman wonderful was the stuff on the inside. (Not that, dummy--I meant her personality!)
Given that Nelson, John, Charles, Demian, and others have made beautiful amps, you might try looking beyond the superficial specs to see the 'personality' of the circuits.
Me? I'm a guy, and you know what that means: I wanted both Raquel and Sophia, and more besides. The wonderful thing about stereo is that an Aleph and a Parasound can happily coexist in the same room. You don't have to choose one and divorce the other.
Given the price of high end gear these days, you might say that you paid your alimony money up front...
Grey
P.S.: Now, if only Lew and Bill (CJ) or someone from ARC would show up to represent the tube camp...oh, never mind. The Luddites would be just as nasty to them as they are to the solid state guys and they'd leave. Seems a pity to me that these numbers-uber-alles critters leave their manners at the door when they come in. Born in barns, they were.
Just what the hell do you think the man's been doing for the last umpteen years?
Go add the Citation mods, the 40 and 75 watters, the Zen series and such together, sit down, and read. What's wrong? Not enough formulas? It's not the formulas that count, silly, it's the creativity that went into putting the circuit together in the first place. Go get the formulas out of H&H.
Early in my writing career, I ran across the saying that writing can be learned, but it can't be taught. That is to say, you can put in all the gunk about where commas go, and dingly participles, and gerunds whirling in little wheels in their cages, but the missing ingredient--the one that can't be taught--is creativity. The sad fact is that 99% of people ain't got it, never will. The other 1% are the ones who change the world. The ability to sit down with a calculator or a simulation program and come up with a functional amp is not creativity. It's mid-fi. Scads of mid-fi circuits hit the market every year. They work. They sell a few units. Then they're replaced by a circuit that's different, yet the same. Another grad student used his calculator and came up with yet another uninspired circuit that makes sound, but not music. The landfills are full of 'em.
The thing Nelson, John, Demian, Charles, and others on their level bring to the table is the creative ability to go beyond the merely functional circuit and come up with something that has a tiny touch of magic. The extra something that the numbers-uber-alles crowd deride as nonexistant. By their standards, audio has been 'perfect' for twenty or thirty years now. Further attempts at improvement are misguided. They're an ironic kind of high-tech Luddite, wanting to hold the world back in a futile quest for more zeros. Most people got beyond that by the mid to late '70s.
John has been kind enough to drop in here and comment on the (admittedly few) circuits of his that have made their way to the web. The balance of his circuits is different from Nelson's. Does that make either of them wrong? No, of course not. Salt does not make pepper wrong. They're both useful in the right time and place and sometimes taste even better when used together.
So far, I've only seen one circuit of Charles Hansen's (the prototype no feedback amp he posted), but I like the looks of it. Again, does he in any way invalidate Nelson or John? No. Our range, our palette if you will, of design options increased by one when Charles offered his schematic.
There is no one way to design an amp, any more than there's a "most beautiful woman in the world." When I was younger, I used to think that there was a "most beautiful woman." (Either Raquel Welch or Sophia Loren, depending on my mood, though right there were sown the seeds of future enlightenment.) As I got older, I came to realize that there were many beautiful women. A little further down the path, I realized that a large part of what made the woman wonderful was the stuff on the inside. (Not that, dummy--I meant her personality!)
Given that Nelson, John, Charles, Demian, and others have made beautiful amps, you might try looking beyond the superficial specs to see the 'personality' of the circuits.
Me? I'm a guy, and you know what that means: I wanted both Raquel and Sophia, and more besides. The wonderful thing about stereo is that an Aleph and a Parasound can happily coexist in the same room. You don't have to choose one and divorce the other.
Given the price of high end gear these days, you might say that you paid your alimony money up front...
Grey
P.S.: Now, if only Lew and Bill (CJ) or someone from ARC would show up to represent the tube camp...oh, never mind. The Luddites would be just as nasty to them as they are to the solid state guys and they'd leave. Seems a pity to me that these numbers-uber-alles critters leave their manners at the door when they come in. Born in barns, they were.
Grey,
From my perspective, this thread had an initial glitch, but at the point where you posted, it seemed to be proceeding in a very civil and constructive manner. Bringing in these tired old strawman arguments isn't helpful at all ("and the side I don't agree with believes"...insert misrepresentation here...).
Regarding the contribution of commercial amplifier vendors, that has of course been a mixed bag. Those who enjoy the social aspect of the hobby/profession will likely continue to hang out here. Those who view it as an extension of their marketing agenda are likely to get a much less friendly reception. That doesn't seem at all unreasonable to me.
From my perspective, this thread had an initial glitch, but at the point where you posted, it seemed to be proceeding in a very civil and constructive manner. Bringing in these tired old strawman arguments isn't helpful at all ("and the side I don't agree with believes"...insert misrepresentation here...).
Regarding the contribution of commercial amplifier vendors, that has of course been a mixed bag. Those who enjoy the social aspect of the hobby/profession will likely continue to hang out here. Those who view it as an extension of their marketing agenda are likely to get a much less friendly reception. That doesn't seem at all unreasonable to me.
Early on in my career, I worked with or initially developed many of the push pull drive stages used today. The reason for a push pull drive stage is to lower distortion due to symmetrical drive (about 21/2 times) and to create an intrinsically stable circuit irrespective of dynamic effects. It also makes the slew rate symmetrical as well.
The example given of a class AB output stage is primitive, and a real output stage is not really as bad as all that, WITH GOOD DESIGN. Higher order distortion can be reduced to almost nothing, with some design effort. Then, the driver stage distortion can be more important, at least to me.
The example given of a class AB output stage is primitive, and a real output stage is not really as bad as all that, WITH GOOD DESIGN. Higher order distortion can be reduced to almost nothing, with some design effort. Then, the driver stage distortion can be more important, at least to me.
john curl said:
John,
My point was to try to give a hypothetical example of a circuit which is "simpler than possible" as it were. And I was essentially arguing that "simpler does not necessarily yield less high-order harmonics" by giving the example of insufficient driver current gain in a class AB circuit. That's all. In other words, if one restricts consideration to, say, class A circuits, it's likely that "simpler means less higher-order harmonics" is much more likely to hold true. But it's not an absolute truth that holds in all circumstances. I'm not in any way trying to call into question your experience, but just shooting the **** so to speak.
GRollins said:
This all sound very plausible, but is utter nonsense of course.....
Place John's circuits in a 'mid-fi' case, with a mid-fi price, and i gaurantee some subjectivists will consign it to the proverbial landfill with alacrity.....
Much (not ALL!) of the so-called 'hi-end' is really 99.9% perception, and 0.1% substance in terms of circuit design, sans the window dressing.........
http://diyaudio.com/forums/showthread.php?postid=476671#post476671
http://diyaudio.com/forums/showthread.php?postid=476677#post476677
http://diyaudio.com/forums/showthread.php?postid=476715#post476715
Hi, Mr. John Curl,
You just have made abstract of your first "Will be published" (maybe?) amplifier tutorial (By Mr. John Curl). Maybe the topic is about "Symmetrical/Asymmetrical designs".
Waiting for the complete paper of this subject.
So, please dont attact any subjective point of view of making amp good sounding amp, even if you feel it isn't right. Truth will come up sooner or later. Anything will enrich our point of view.
You just have made abstract of your first "Will be published" (maybe?) amplifier tutorial (By Mr. John Curl). Maybe the topic is about "Symmetrical/Asymmetrical designs".
Waiting for the complete paper of this subject.You are right. Unlike low distortions, sound quality is unmeasureable, while we can measure distortions.
So, please dont attact any subjective point of view of making amp good sounding amp, even if you feel it isn't right. Truth will come up sooner or later. Anything will enrich our point of view.
Andy C, I still think that you confuse series 'complexity' with parallel push-pull design. Parallel push-pull design reduces the current change necessary for changing voltage and tends to cancel much of the inherent distortion as well.
Series design adds devices in series, which can reduce total distortion, BUT usually multiplies the order of the distortion as the distortion in one stage is passed through a following stage.
Both design approaches take more parts than absolutely necessary to make a primitive amp. I prefer the parallel approach. It still has a SIMPLE through-path, or transfer function.
Series design adds devices in series, which can reduce total distortion, BUT usually multiplies the order of the distortion as the distortion in one stage is passed through a following stage.
Both design approaches take more parts than absolutely necessary to make a primitive amp. I prefer the parallel approach. It still has a SIMPLE through-path, or transfer function.
gone for a day or two....
and this thread has developed from "interesting books" to a discussion on design philosophies and implementations.
to the point:
I am a newbie to DIY audio
I am not new to Physics
I have had limited exposure to circuit design and construction
How did Richard Feynaman enter into the discussion other than a passing quote from either Mr. Pass or Mr. Curl (and taking off on its own)? BTW. anyone can read "Six easy pieces" and get something from it. The Feynamn lectures are not for the lay person to read, as some Physics or Mathematics background is needed
All here should be greatful that ANY designers hang out here and are willing to provide guidance, and inspiration.
Just a thought or two.
stew
and this thread has developed from "interesting books" to a discussion on design philosophies and implementations.
to the point:
I am a newbie to DIY audio
I am not new to Physics
I have had limited exposure to circuit design and construction
How did Richard Feynaman enter into the discussion other than a passing quote from either Mr. Pass or Mr. Curl (and taking off on its own)? BTW. anyone can read "Six easy pieces" and get something from it. The Feynamn lectures are not for the lay person to read, as some Physics or Mathematics background is needed
All here should be greatful that ANY designers hang out here and are willing to provide guidance, and inspiration.
Just a thought or two.
stew
Stew, I agree that we have gotten off the original subject. I also agree that reading Feynman is difficult. I have most of his books, but I have trouble also. I talked this over with my friend, Jack Bybee, who used to work with Richard Feynman. He told me that Feynman tended to skip over important logical steps, as if they were obvious. I found this also with the late Richard Heyser. You know, the words are simple, BUT how did he come to that conclusion? Therefore, Feynman puts me to sleep (really) while reading.
Back to the audio reference books: There are books that give one person's point of view that contain good material, such as Doug Self's book. However, it would be almost impossible to design anything different that what Doug Self designs with only his book as reference. Most serious reference books have moved away from discrete design into IC's, OP AMP theory, or CMOS. There are older books that have important chapters, such as the 'Radiotron Designers Handbook', or 'Electronics and Radio Engineering' by Terman. These old, but relatively complete texts give numerous insights to audio design if you look through them.
Finally, I would find 'OLD COLONY' on the internet and look that their audio book selection. If it is available, they usually have it, and their selection is very good.
Back to the audio reference books: There are books that give one person's point of view that contain good material, such as Doug Self's book. However, it would be almost impossible to design anything different that what Doug Self designs with only his book as reference. Most serious reference books have moved away from discrete design into IC's, OP AMP theory, or CMOS. There are older books that have important chapters, such as the 'Radiotron Designers Handbook', or 'Electronics and Radio Engineering' by Terman. These old, but relatively complete texts give numerous insights to audio design if you look through them.
Finally, I would find 'OLD COLONY' on the internet and look that their audio book selection. If it is available, they usually have it, and their selection is very good.
let's kill this thread
Mainly because it has strayed SOOO far away from the original intent.
Perhaps a list of good and or usefull reference materials could be cobbled together from experienced, knowledgeable members.
Many of the posts I read here make references to rather obscure design or philosophies.
Admin, please kill this long winded and now pointless thread. Perhaps members could make direct contributions through Admin or a moderator in charge of said list.
Thanks again to all that contribute in a meaningful way.
stew
Mainly because it has strayed SOOO far away from the original intent.
Perhaps a list of good and or usefull reference materials could be cobbled together from experienced, knowledgeable members.
Many of the posts I read here make references to rather obscure design or philosophies.
Admin, please kill this long winded and now pointless thread. Perhaps members could make direct contributions through Admin or a moderator in charge of said list.
Thanks again to all that contribute in a meaningful way.
stew
Does anybody have any thoughts regarding Sedra/Smith's Microelectronic Circuits as an introductory or second text?
Table of Contents here:
http://www.us.oup.com/us/companion.websites/0195142519/about/contents/?view=usa
Table of Contents here:
http://www.us.oup.com/us/companion.websites/0195142519/about/contents/?view=usa
Hi, Everybody,
Sorry, I just want to make clear.
Hi, Mr. Pass,
Sorry, I just want to make clear.
Hi, Mr. Pass,
Sorry, I should have checked before posting. The exact post is
It can be found here http://www.diyaudio.com/forums/showthread.php?postid=446327#post446327
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