John Curl's Blowtorch preamplifier part II - Page 3115 - diyAudio
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Old 8th December 2012, 12:45 PM   #31141
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Quote:
Originally Posted by Jay View Post
Why is 1000V/us better than 60V/us? Is it audible (Talking about 50W or less)?
I believe there is the same progress between 50 and 100µs/v than between 1000 and 2000. You know by experience that everything can always be a little better. It is like signal/noise ratio, or distortion levels. Where is the limit ?
At the point you are satisfied enough.
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Old 8th December 2012, 12:50 PM   #31142
Jay is offline Jay  Indonesia
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Originally Posted by Esperado View Post
I believe there is the same progress between 50 and 100µs/v than between 1000 and 2000. You know by experience that everything can always be a little better. It is like signal/noise ratio, or distortion levels. Where is the limit ?
The limit will be verified in a controlled blind test.
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Old 8th December 2012, 12:56 PM   #31143
fas42 is offline fas42  Australia
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I would like to add a last philosophical word.
About numbers.
In the previous demonstrations, we have seen that numbers like slewrate have no absolute signification outside of their context.
Same thing about distortions, that everybody knows, todays, that they poorly reflect listening experiences.
Numbers are fine, provided they reflect the true situation of the complete system in operation. And that is still not being done, because everyone says it's too hard ...

We're still in the situation of creating a Formula I car where the engine guys work out the perfect engine, the suspension guys the ideal suspension, etc, etc, in beautiful isolation from each other. They hand the results to some garage mechanic to assemble, and the poor test driver flies off the road on the first corner. "Not my fault!" says the engine guy, "It tested beautifully!!" ... "Not my fault!" says the suspension chap, "... ...

Frank
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Old 8th December 2012, 12:59 PM   #31144
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This is all very amusing. However, I personally do not believe that the ABX double blind test is capable of separating anything that is properly set up. I failed it, myself, 33 years ago or so.
It is the test that has the limitation, not the human ear. Nobody here, at least, seems to look at the test itself, for its limitations. My critics want to believe that a null result in an ABX test is useful, and they want Stereophile and TAS reviews to do it too. They all tried it and came to the same conclusion as I did 33 years ago.
However, I have successfully passed blind A-B tests, where I simply chose which I like A or B best. That works, AND it can be made as 'double blind' as an ABX test. YET, that is how I compare differences in audio equipment successfully. Some here should try it.
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Old 8th December 2012, 01:00 PM   #31145
Jay is offline Jay  Indonesia
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Originally Posted by fas42 View Post
We're still in the situation of creating a Formula I car where the engine guys work out the perfect engine, the suspension guys the ideal suspension, etc, etc, in beautiful isolation from each other. They hand the results to some garage mechanic to assemble, and the poor test driver flies off the road on the first corner. "Not my fault!" says the engine guy, "It tested beautifully!!" ... "Not my fault!" says the suspension chap, "... ...
It is clearly the test driver mistake. Find another story
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Old 8th December 2012, 01:02 PM   #31146
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Originally Posted by abraxalito View Post
but its SQ is nothing much to do with the slew rate number.
I will say that when the previous curve i had published ( bandwidth in the loop) will be flat up to 10Khz.
Agree on RFI.
I believe some transient high order distortions at hf can be demodulated in the audio range if devices not fast enough.
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Old 8th December 2012, 01:09 PM   #31147
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Originally Posted by john curl View Post
It is the test that has the limitation, not the human ear.
At least John, try to justify your assertions. Your authority and your charm are not sufficient to convince most of us, poor heretics.
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Old 8th December 2012, 01:13 PM   #31148
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The proof is in the comparison between components and long term listening. If one cannot live with a product happily, even though it went through ABX testing successfully, then one should not keep that product in ones audio system, but put in another. That is what successful listeners do.
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Old 8th December 2012, 01:17 PM   #31149
DF96 is offline DF96  England
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Quote:
Originally Posted by Esperado
My words !
Sorry, I didn't realise I was quoting you. If you said that, then I agree!

Quote:
Originally Posted by Jay
No. We ALL know that $1 amp sounds different than $1000 amp. But when it is between $900 and $1000, some people start to ACCUSE others. The mission is to attack the person not the truth whether $900 and $1000 are different or not.

This accusation is simply based on the fact that these audiophools are really fools, don't know what they are doing, have no ability to measure distortions, etc. Not whether there is really differences.
Some audiophools may be fools. Most are not, but may be misguided or simply herd-following or simply in denial about the strength of placebo and other similar effects. It is the claim which is being doubted, for sound scientific reasons, not the person. If the person making the claim then securely attaches himself and his reputation to the claim then that is a matter for him. If I hug a tree then I can just step away when the tree is cut down. If I live in a treehouse then I go down with the tree, but that is my choice.

Some of these extraordinary claims may be true, but we will never know if they are never tested.
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Old 8th December 2012, 01:37 PM   #31150
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Well, enough of trying to explain my position here.
Now, as I was informed previously on this thread, I got another 'product of the year' award in the Jan 2013 issue of TAS that just arrived yesterday.
What is more important than doing a test that will show nothing, even if I went through the time and trouble to do it, is how in the heck did I get this new award, when everybody knows that I don't deserve the honor? Why didn't they give it to someone else with a more sensible design? That is the most important question!
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