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John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
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Old 19th November 2018, 12:59 PM   #9911
scottjoplin is offline scottjoplin  Wales
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Could this be why Nelson's amps sound so good? They have a beautiful simplicity of design and function and he's a nice guy who everyone loves and trusts.

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Last edited by scottjoplin; 19th November 2018 at 01:10 PM.
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Old 19th November 2018, 01:09 PM   #9912
DF96 is offline DF96  England
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Quote:
Originally Posted by tapestryofsound
If it sounds good, it's high fidelity.
Of course, we have to allow creative people the freedom to empty words of their meanings. That in turn gives us (who are trying to use words for meaningful communication) the freedom to ignore what the creative types say.

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Of course I understand the difference between the creation of music and the reproduction of music.
Then why pretend that you do not?

Is this the 5 minute or the 30 minute argument?

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I think the real issue is that your father never gave enough of his time to be with you as a child. Time that you needed, and without realising it, projected it onto me. You maybe in denial of this, but this is what upset me. How dare you? Would you say this to my face? I very much doubt it. Believe me when I say that amongst my peers, I am also one of the good guys and would do anything to help other photographers, including your father if I was ever lucky enough to have met him.
So now you are a world expert on cod psychology too?

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Originally Posted by john curl
So we must say that HI FI REPRODUCTION is something different than guitar amp amplification, so let's keep the two separate.
I am glad that from time to time JC says something that I can fully agree with.
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Old 19th November 2018, 01:13 PM   #9913
dadod is offline dadod  Croatia
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Originally Posted by john curl View Post
I really don't think than most here understand serious audio design at all. It isn't just computer simulations, although it might help. It isn't just putting something together and listening, although that might be part of it, and it cannot not be just a specific set of measurements, like THD that look good in print, either. It is a combination, of good initial concept (topology) coupled with proper parts selection, and finally tuning the combination with both listening tests and measurements. Usually something compromises the design effort. It might be cost, it might be heatsink limitations, it might be size, it might be bull-headedness of one of the principals as to what is important or not important. Usually there is no perfect execution of any design, like an amp, and that is what makes it a challenge to try to do one better.
John, I think that you mystify audio amp design to much, just to justify an amp (power or pre) cost in tens thousands of dollars. It should contains some “mystic components” and some “tuning” and that to be secret of chosen ones.
A good amp (excellent one too) is just good engineering with good proven components. Design now days start with simulator and that is most useful and important tools which gives the result, if one knows electronic theory, very close to final amp. Testing and measuring are next steps of course, the PCB layout is equally if not even more than the simulation.
Listening is at the end, very important, but that one is contaminated with audio magazines and golden ears.
Best wishes, Damir
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Old 19th November 2018, 01:31 PM   #9914
scott wurcer is offline scott wurcer  United States
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Originally Posted by dadod View Post
if one knows electronic theory
That does help, I forgot one yesterday The Art of Electronics, by Paul Horowitz and Winfield Hill. If you can find a reference here to "voicing" ,etc. please point it out.
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Old 19th November 2018, 01:46 PM   #9915
billshurv is offline billshurv  United Kingdom
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John Curl's Blowtorch preamplifier part III
Quite. And I am sure you are considered well versed in the art!

Thinking about it, the problem is that 'art' appears to have shifted in meaning from back when the only degree you could get was an arts one. D.Self for example is MA!
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Old 19th November 2018, 02:03 PM   #9916
PMA is offline PMA  Europe
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Originally Posted by Jakob2 View Post
PMA, i beg your pardon, but you have to be more specific. For what did i nor present any "fact" ?

Wrt the preamplifier test i wrote a description (inluding the measured numbers of both variants) of the test approach overall several times and reported the results.

So, you must mean something different, but i again i don´t really understand what missing "test description" or missing "test files" you are referring to.
I apologize if I missed something in this extremely long thread. It might have happened easily, as I am often occupied with my job and thus I do not read everything in the forum.
Is there a test protocol or a written description of your preamplifier test, if yes, I would be interested to see it. Or an external link to your website or to the test description and its results? I assume it was a serious, professional test.
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Old 19th November 2018, 02:10 PM   #9917
PMA is offline PMA  Europe
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Originally Posted by chris719 View Post
The modern Porsche and Ferrari design processes are the exact opposite of "high-end" audio. They are data-driven and rely on extensive FEM simulation of every component. They have objective targets. Ferrari has multiple of their own state-of-the-art datacenters just for their F1 program.
That was exactly my point and that was why I have shown that vintage 1936 Mercedes-Benz 500K car, as a parallel to audio high end. Nice, glossy, shiny, heavy, big fuel consumption. However, nice to look at and I like it . Below one near Prague.
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Old 19th November 2018, 02:13 PM   #9918
scottjoplin is offline scottjoplin  Wales
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I'd hope it came with a chauffeur
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Old 19th November 2018, 04:12 PM   #9919
Max Headroom is offline Max Headroom  Australia
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Originally Posted by dadod View Post
.
Listening is at the end, very important, but that one is contaminated with audio magazines and golden ears.
Best wishes, Damir
Hi Damir.
Agreed, simulation allows 'virtual' optimisation (according to models) that can get incredibly close to the target depending on the application.
In the case of audio this still applies, but the models are ultimately too course to predict the very fine effects of parasitic characteristics in components active and passive, and the consequential subjective effects presented to the listener.
One can read infinite reviews but the final choice is in the ear of the listener.....some gear sounds good or 'right', and plenty of other stufff does not, hence the eternal audiophile 'quest'.
It seems that you have invented and proven many designs (we are interested to to hear the final results of your RNM collaboration I am sure) and these designs of yours have have evolved....why ?.
'Why ?,' as in what have you found wanting in your incremental designs that has inspired you to chase 'advancement'....in what areas...max power, THD, THD Spectrum, IMD, IMD Spectrum, N, N Spectrum, BW, DF, DF/Spectrum, etc, etc.
Have you practiced subjective 'voicing' by for example swapping parts that SIM (models) says should be indistinguishable or moving NFB take off point and/or NFB series/shunt components, or different pcb substrate etc etc.......?.
I applaud your efforts, and RNM's initial appraisal of your mutual design is by all accounts is first class, I am interested to know your design process ?.


Dan.
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Old 19th November 2018, 04:15 PM   #9920
john curl is offline john curl  United States
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As I said, guys.
Now when it comes to 'tuning', it is just a word I chose 'on the fly' to describe adjusting and looking at distortion 'quality' and getting it optimized. Just today I have a fairly large power amp waiting in my lab to be tested. It already works, but I had to change the value of the output emitter resistors from what the factory put in. I hope that I calculated the right value.
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Last edited by john curl; 19th November 2018 at 04:20 PM.
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