John Curl's Blowtorch preamplifier part III

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#19,321
gpauk said:
Meanwhile - please keep calling out the BS when you see it!
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It depends a lot on how one goes about it. If someone says, "this cap sounds different that that one, but I don't have a theoretical explanation, and I don't have perceptual research data to show because the research has never been done," it doesn't necessarily prove that the claim of an audible difference existing is BS, and its no justification for flaming someone. You don't know for a fact whether the claim is true or not.
 
#19,324
scott wurcer said:
What was the context of the listening test, listening only to the noise in the previously empty bands or with everything? With the masking of the LP noise (-58dB), it would hard to claim adding -92dB of additional noise is audible (~.0004dB difference).

I never got beyond interesting information with this technique, the goal was to try and show the possibility of the noise created in the blank spaces being different than that predicted by conventional measurements. Another possibility is that the growth and decay of the noise floor in the empty spaces shows something unexpected.
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I would back the highlighted possibility as a possible source of audible differences but don't think it has been measured in a way that shows what may be audible.

The measurements of XX3stksm are interesting & show some possibility for further research. I wouldn't so quickly dismiss the resultant noise generated by the DAC. Some questions occur - I presume this DAc generated noise above 800Hz is also being generated within the 800Hz bandwidth, we just can't see it on the FFT? So on a full range signal there is this noise being accumulated throughout the bandwidth. Noise is additive & especially when it is fluctuating (as is the case here), I wonder how audible it can be & if we could measure it & see the fluctuations in real time, what visibility we might have into the possibility of this mechanism?

I don't see any possible way of doing this in a way that realistically evaluates what may be happening with real music.

I don't know if perceptual studies have been done using fluctuating noise floor levels/variability & audibility with real music?
 
#19,325
chris719 said:
First of all, I was responding to Mark.

Second, what the hell are you talking about? I am not trying to be insulting, I'd tell you that upfront. I genuinely have no clue what you mean and what you are getting at here.

Ok - you know what - forget it.

I posted a perfectly sane reply to Mark, which he sort-of agreed with despite pointing out a few valid differences. Then you come in with this barely decipherable paragraph of crap about telescopes and pyramids. All because you don't take the time to READ and understand who is talking to whom.
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gpauk said:
T does that... I put it down to hallucinogens, or, more likely, things very much lost in translation!

Meanwhile - please keep calling out the BS when you see it!
Absolutely no harm in keeping folk on their toes, and everyone here should have a thick skin. It would get very boring if there was no contention - it's what helps promote progress!
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Some members come here to share their preconceived notions, also known as audiophile fantasy. They don't like it when they are disrupted with challenging questions and go on "block" mode. They then continue on with their fantasy sharing. They aren't interested in learning facts.
 
#19,326
Markw4 said:
It depends a lot on how one goes about it. If someone says, "this cap sounds different that that one, but I don't have a theoretical explanation, and I don't have perceptual research data to show because the research has never been done," it doesn't necessarily prove that the claim of an audible difference existing is BS, and its no justification for flaming someone. You don't know for a fact whether the claim is true or not.
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Carl Sagan made the "Extraordinary claims require extraordinary evidence" statement popular (in fact much older, I think Laplace is documented as the first mention). This statement is central to the scientific method, and a key issue for critical thinking, rational thought and skepticism everywhere.

Other than presenting the evidence to support the extraordinary claim, you have two options:

1) Deny the statement, which would put you outside the scientific investigation methodology.
2) Deny the scientific investigation methodology applies to audio.

Do it at your own peril, but don't expect to be taken seriously in either case.

Otherwise, until such extraordinary evidence is presented, ignoring the claim (with or without qualifying it as BS) is perfectly justified. Replace BS with quackery, voodoo, snake oil, etc... as appropriate.

I would think most people are ignoring such extraordinary claims without proof, and the silence is encouraging the perpetrators, until a vocal minority kicks in (count me too), that the perpetrators then conveniently qualify as "noise".
 
#19,327
Markw4 said:
It depends a lot on how one goes about it. If someone says, "this cap sounds different that that one, but I don't have a theoretical explanation, and I don't have perceptual research data to show because the research has never been done," it doesn't necessarily prove that the claim of an audible difference existing is BS, and its no justification for flaming someone. You don't know for a fact whether the claim is true or not.
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There already are many known properties in audio replaying electronics. When someone keeps harping on how much better sound is produced by a DAC with lower distortion that's even lower than what's already inaudibly low market standard, it should be called BS even if that person doesn't have a theoretical explanation and perceptual research data.
When you see a dog dropping on the sidewalk, do you avoid or step on it? You wouldn't step on it because you already know that doing so will ruin your day. When someone posts on a forum saying that there is this dog dropping with different color due to improved diet for that dog and recommends that stepping on it will improve your mood, you would call that DS. Or at least you should unless you don't understand the basics of animal excrement.
 
#19,329
All it takes is ears: e.g. people hearing a difference in DAC's, caps, amps, etc when they actually listen seriously. I KNOW that DAC's need improvement, it comes both from LISTENING, but also from theory. Amps are not perfect either. I find making a 'perfectly sounding' power amp still a serious challenge, even if I am given free rein to do what I think is necessary to build it. This is beyond measurement of just test tones.
Now, Markw4 is TRYING to be both objective and subjective and I admire him for it. It is a rough road to travel when you can hear differences and people tell you that it is impossible to do so, unless you made a mistake. Keep on listening, Markw4 and give circuit designers a direction to 'improve' according to your findings.
 
#19,335
john curl said:
The distortion that we can detect is not usually 'harmonic or even IM distortion' it is something more difficult to measure, like Hirata distortion (look it up)
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I never saw anything there but relationships between ordinary distortion magnitudes. You should be careful, I don't think folks here are into this approach as much as 40yr. ago.

To paraphrase, Hiraga contended that it wasn't the quantity of an amplifier's nonlinear distortion that determined its sonic footprint so much as its quality; not the absolute level of that distortion but its pattern.
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#19,336
john curl said:
All it takes is ears:
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With some sprinkles of peeking and you have a delicious audiophile meal.
e.g. people hearing a difference in DAC's, caps, amps, etc when they actually listen seriously. I KNOW that DAC's need improvement, it comes both from LISTENING, but also from theory. Amps are not perfect either. I find making a 'perfectly sounding' power amp still a serious challenge, even if I am given free rein to do what I think is necessary to build it. This is beyond measurement of just test tones.
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I wonder why you left out the imperfections of speakers. Perhaps because the degree of imperfection is off the chart compared to DACs and amps... :scratch2:
 
#19,337
EUVL said:
Is it not true that loudspeakers have much much higher distortion than any electronics upstream ?
If so, what is the point of having DAC's of amps with -140dB distortion, when the speaker can only do (say) -60dB ?
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:shhh: :shhh: :shhh: You are splashing water on the face while they are enjoying their audiophile dream. You will wake them up to the reality and they won't be in the best mood. Just a precaution...
 
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