John Curl's Blowtorch preamplifier part II

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Experience and experiments show that the human ear finds 7th harmonic extremely objectionable.

Also, scientific experiments show that the human ear is sensitive to distortion in frequencies far above 20 KHz, though not to fundamentals.

Possible, a good opportunity for me to learn something new.

Could you quote a few of this prior work/experience/experiments/scientific experiments? There's certainly quite a few that I am not aware of.
 

iko

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I made absolutely no assumptions about any audible effects of cartridge resistive loading.

You said "Assuming there would be a difference in the subjective perception." What were you referring to as "subjective perception" if not the audibility of cartridge loading? Sorry if I misunderstood, please explain.

You are perfectly free to design and perform another better test that would reveal and explain the subjective testing results. If it makes sense (nobody can afford to test any possible permutation of factors, moon phase included) you may even get some support in your endeavour.

Or you may chose to happily live ever after, without results and explanations, like so many other contributors here.

Fortunately my happiness is not strongly correlated with audio (in the bigger scheme of things).

Unfortunately I have no access to adequate instrumentation so I rely on people like you to do it. But it's pretty academic in the end, as the answer doesn't have a measurable practical importance in my life.
 
You said "Assuming there would be a difference in the subjective perception." What were you referring to as "subjective perception" if not the audibility of cartridge loading? Sorry if I misunderstood, please explain.

Semantics. "Assuming there would be a difference in the subjective perception." == "If there is a difference in the subjective perception"
 
This is not normally true, Joshua. Assuming that you mean that the amp has insufficient slewrate, that would surely show up in THD measurements, especially done at higher frequencies. That is one reason why Bob Cordell for instance advocates THD-20 measurements. I agree that 1kHz measurements have much less chance to turn up the effects of insufficient slew rate, but a designer who is aware of these issues would use measurements that would show it.

One example of 'looking at the schematic and know how an amp sounds' is this. You can often see from the circuit diagram whether the slewrate is sufficient or not (not always, but sometimes), so that would be a good indication that that amp wouldn't sound like the best ones out there.

jd


1. I was referring to the fact that THD alone cannot tell the audible sound quality of an amp, not to designers skills.
2. Enough slew rate in itself doesn't tell the audible sound quality of an amp, different amps with similar slew rates sounds differently.
 

iko

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Some people call this semantic evasion :) (it's a joke)

And then you followed that statement with the implications of the assumptions. So, in theory, for the moment, you explored the possibilities. That's what I did too, I explored your a), b) implication. I accept that you will not answer whether you hear the effect of different cartridge loading or not. As you said, you don't owe anybody an answer.

Edit: it may look otherwise, but syn08, I'm not trying to give you a hard time. I'm just trying to clarify some things. It's a very difficult medium this internet. John would have sent me packing long ago :) Right John?
 
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That's irrelevant to the incorrect assertion you made. Musical instruments have seventh harmonics. So do voices. This cite is about note frequency relationships, a totally different issue.

Your cite of the Oohashi article (which is fatally flawed; see discussion elsewhere) also does not support the claim you made about distortion above 20kHz. Oohashi does not talk even a little bit about distortion.
 
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1. I was referring to the fact that THD alone cannot tell the audible sound quality of an amp, not to designers skills.
2. Enough slew rate in itself doesn't tell the audible sound quality of an amp, different amps with similar slew rates sounds differently.

No. You said (and I quote):

"Not at all. Lower THD figures are easily achieved with NFB and GNFB. When large amount of NFB is applied without proper consideration of the appropriate Slew Rate, measurements of THD will be excellent, while the sound will be bad."

This is incorrect. Insufficient slew rate turns up in THD measurements, IF you know what to look for.

jd
 
Your cite of the Oohashi article (which is fatally flawed; see discussion elsewhere) also does not support the claim you made about distortion above 20kHz. Oohashi does not talk even a little bit about distortion.


Oohashi article is about HFC (High Frequency Components) – when HFC are affecting the brain, it applies the same to natural harmonics and to distortion.
 
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Skating on thin ice Joshua_G? :)
 

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SY, seventh harmonic is avoided in many musical instruments, if possible. You should know this. Seventh harmonic is always out of tune. It is the worst example. Doesn't anyone here actually use Google to find out these things?
In musical reproduction, seventh harmonic appears to be the very worst harmonic to add to a hi fi system reproducing music. I think that this is what Joshua is trying to convey, Of course, seventh harmonic occurs in nature.
Of course, if you want to add a 'metallic sound' to your hi fi, this is the easiest way.
 
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