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In Reply to: On a different note: Response to Morricab on Amplifiers posted by theaudiohobby on February 8, 2007 at 05:07:29:
I mean, serious people? I'm referring to this:>>"...as they preserver harmonic content, and hence the timbre(sound quality) of the music." <<
Again, does any real, serious person think that harmonic distortion equates with "preserv(ing) harmonic content"? It seems to me a remarkably simplistic--and transparently incorrect--claim, and I notice that it is not attributed to anyone. Is there any citation in the original?
To state the obvious, "preserving the harmonic content" means reproducing precisely what's on the recording--harmonic content and all.
Support for such the disputed claim would require showing NOT that SETs have a nice distortion signature, but that other types of amplication REDUCE harmonic content MORE than SETS do. But a low-distortion amplifier with reasonably wide bandwidth and accurate frequency response will reproduce the harmonics on the recording as well as it records the fundamentals--and will do so with greater accuracy than a higher-distortion amp.
What am I missing?
Follow Ups:
I did not see that at all. The mystery quote simply disputes the assumed connection of level of distortion with ability to "...preserver [sic] harmonic content..."The article in HiFi News appears from the OP to be concerned with models for amplifier stage distortion. It would be interesting to see if the model includes distortion dependence on signal level. A push-pull tube amp with output transformer has a granularity determined by the requirement that the output transformer core magnetization switch direction at the signal zero-crossing. This is independent of bias current, but strongly dependent on details of core composition and construction.
If distortion is modeled or measured at a single signal level, the comparison is not worth much.
Interesting point about the output transformer. Do you have any references where you found this out? I would like to read them. Of course for a Class AB transistor amp (except McIntosh) there seems to be other problems (ie. crossover distortion, not only mismatch under static tests but also a different cause from the music signal itself).I found some other stuff by this guy Lesurf. He has done some interesting analyses. Like this on Class AB transistor amplfiers (that is the primary focus anyway).
http://www.st-and.demon.co.uk/AudioMisc/distortion/page1.html
http://www.st-and.demon.co.uk/AudioMisc/distortion/page2.html
http://www.st-and.demon.co.uk/AudioMisc/distortion/page3.htmlPage 3 is particularly interesting and one possible explanation for why sine waves don't tell the whole distortion story.
"Again, does any real, serious person think that harmonic distortion equates with "preserv(ing) harmonic content"? It seems to me a remarkably simplistic--and transparently incorrect--claim, and I notice that it is not attributed to anyone. Is there any citation in the original? "Well, he is discussing the concept of benign distortions, which has gained a lot of traction in SET- afficiondo circles. I imagine that a lack of context and the unfortunate sleight of editing is cause for your misinterpretion of his comments.
On side note, I am beginning to think that high-output impedance amplfiier have gained a lot of traction because of the demise of tone controls and equalisations in most high quality audio equipment. The issues that these components sought to address are still there, and these amplifiers provide a method if inflexible means of achieving the same. I say that partially because of very high input impedance speakers which were more common back in the day have not gained any traction in the marketplace, rather most folks use these amplifiers with relatively low impedance speakers where frequency response modification is most audible.
Music making the painting, recording it the photograph
You are missing the audibility of those distortion products. Type is more important than level (did you read the Keith Howard experiment in Stereophile? Or the Cheever Thesis?). If the distortion is inaudible up to a certain level then it is not really relevant. It turns out that even very low levels of high order harmonics are audible whereas quite high levels of low order harmonics are not. As to "preserving the harmonics" I agree that this is gibberish and a turned around way of saying that the distortion the amp produces is simply less audible if higher on an oscilloscope.
Yes, I've looked at the Cheever thesis and read the Stereophile piece. This is important stuff, dispending with one of the more common explanations for why people like SET stuff so much.I just find it hard to believe that there are serious audio types in the world that think that you can "preserve" something about the original signal by distorting it more.
Let's take a look at the full extract shall we (emphasis added):
--
I have seen arguments that SE arrangements or those with no overall feedback, 'may have higher distortion, but this does not matter as they preserver harmonic content, and hence the timbre(sound quality) of the music.' Alas as the above results show, this argument simply does not hold water unless we listen to one note at a time and avoid anything but the simplest chords using perfect integer ratios!
--For starters as quote is not attributed to anyone in particular how do we know that it isn't just a paraphrase representing the writer's opinion of the views of SET advocates, or for that matter just something that some non-technical audiophile wrote in an internet post?
More importantly however the quote doesn't actually *attribute* the preservation of harmonic content to the "SE arrangements" higher distortion, does it?... yet that certainly appears to be *your* interpretation, i.e.:
--
I mean, serious people? I'm referring to this:
> > "...as they preserver harmonic content, and hence the timbre(sound quality) of the music." < <Again, does any real, serious person think that harmonic distortion equates with "preserv(ing) harmonic content"? It seems to me a remarkably simplistic--and transparently incorrect--claim, and I notice that it is not attributed to anyone. Is there any citation in the original?
--What gives? Is this a case of "When in Rome"?... you certainly come off like just another ranting PH "objective" indignant-eophile!
How about a little more care in the future?
TIA
...I'm the one coming off as indignant here. What's odd as that we--you and I--are making the same point more or less and you're attacking me for it. "Does anyone really think this?" is, I think you'll agree, equivalent to asking "is he creating a strawman?"So it cuts two ways: I'll admit that I think anyone who believes what this guy says the SET-heads believe is not technically astute.
But I also am not convinced that serious people believe what he seems to be attributing to them. Notice that I, too, asked if there was a citation in my first post in this thread. Consider me skeptical.
I need to be careful here. I just realized--I had not noticed this before--that this is taken from a current audio magazine, which means that I should not comment further.
"I'll admit that I think anyone who believes what this guy says the SET-heads believe is not technically astute.(emphasis added)
Good! That's showing more care. :)
As for indignation that's certainly how I interpreted your comments, e.g. "I mean, serious people?", seemed a little indignant to me, heck one could even be forgiven for suspecting undo haste on your part, i.e. surely you meant "serious ly people?", no?
But you know perhaps I'm wrong, perhaps "indignant" isn't appropriate, in fact I'm more inclined to suspect "excitable" is more fitting, after all in response to my suggestion you exert greater care (something you seem to more or less acknowledge) you claim I'm "attacking" you!... goodness!
> > I'm more inclined to suspect "excitable" is more fitting, < <...just how bored (i.e., un-excited) I am right now...
You're right on one point though--I was a little careless. I did not feel that you were attacking ME--but that you were attacking my argument, which you also were making, more or less, which seemed weird.
Would you please point out the argument I was making that you seem to believe was in agreement with yours... Oh, and while you're at it, please point out the agrument you were making.To recap, my (initial) post (to you) was entirely concerned with cautioning you against careless reasoning, i.e. pointing out the quote (whatever its source) didn't even support the notion of equating harmonic distortion with "preserv(ing) harmonic content"!
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