John Curl's Blowtorch preamplifier

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myhrrhleine said:


OK,
now please explain, or give a weblink for an explanation,
why are the results of this small sample applicable 100% to all people all the time?
how does testing 1000 Jims apply 100 % to Pavel or John?


Good point. I'll weasel out by saying that it is not 100% applicable to all people. I accept that the limit of where the difference cannot be heard anymore is different for different people.

However, when you take a large enough sample, you get close. In a few months, sampling 1000 americans will let you predict pretty accurate how the other 150 million or so will vote. It will not predict how an individual person will vote, but how the cohort will vote.

If you do a DBT that consistently correctly identifies a BT against an AYRE, you have pretty well establed that they have an audible difference, period.

If not, you have pretty well established that there is no audible difference between the two *in that particular setup*. If you then make sure that that particular setup is better than most, you can conclude that most people will not be able to hear a difference between a BT and an AYRE, based on sound alone (and this is an important qualifier).

Everything is about statistics, including science.

Jan Didden
 
PMA said:
[snip]Just today we listened to CD/SACD, true DSD (Telarc and Harmonia Mundi) vs. CD layer and CDs, all very good recordings of classical music. It is a puzzle for me, and my visitors, that someone can be that deaf and not to hear the difference.


I could recommend a few books that would clear that up 😉 . It has, of course, nothing to do with 'deafness'. Your use of that term shows that you have a long way to go to understand the issues. Nothing personal!

Jan Didden
 
They like to pretend they are deaf, and make us appear that way, also.
That is also a 'vested interest'.
Some academics actually appear to have come to the conclusion that very little is important between audio equipment sonically and they developed tests to 'prove' their initial belief.
 
janneman said:
Andre, this may be your opinion, but none of the perception and memory studies I'm aware of support this.
Jan Didden

Just for an example, after not listening to a system for more than a month, I immediately noticed that there was something wrong with the soundstage and bass (compared to what I know it should sound like). I've found that a set of cables (screened twisted pair) was inserted the wrong way round, after fixing it, everything was back to normal.


janneman said:
Everything is about statistics, including science.
Jan Didden

Yes that's a sure way to design an "average" piece of equipment, if you want something exceptional you have to do better. 😀

André
 
In the case of two resistors compared, the question now is, "which one is more correct?"

Funny that you bring that up.

Myself I'm wondering about that now for a long time. Though it's an essential question, there does not seem much interest in it, especially since the obvious question is you can't decide what's more correct - only which sound you prefer.

Only imaginable exception I see is the case where one has access to the mastering equipment, so that one is able to hear it the way it was mastered.

A little anecdote...

Thinking about this, I always remember a posting I once read; it was of a guy that listened to - amongst others - 2 sets of speakers of the same manufacturer, of the same family (same surroundings, amps ...).

Just that one set was top of the line, the other set the offering below the top.

Well, he bought the top of the line speakers, because "they had more bass". Otherwise he wrote (tremble, midrange) they sound the same.

Looking at frequency response it became immediately clear that he was perfectly right: a nice +3dB humb at about 100Hz was the cause.

He would have gotten that hump cheaper using a band equalizer.

So this was what his hearing brought him in the end - due to the lack of a real reference.

Have fun, Hannes
 
KBK said:
Floyd is a smart measurements guy, but lord knows he's not a Speaker designer. Not by a long shot. That's always been my take on the subject. He's been in the system a long time, and casts a long shadow. So there's bound to be differing opinions on the situation.

No! Harmon did the blind tests because they want to know what sort of sound folk prefer! They couldn't get that data cleanly unless they hid the equipment.


Notice: I said prefer. Their goal is to sell product and they can't sell it if the sound is rebarbative, and they can only optimize sales if they are producing sound most people like.

They have both pro and consumer segments and what the members of these segments prefer may differ, but the principle remains the same both for their speakers and electronics.
 
The idea has never entered my mind
that moamp or anyone else would want to steal, use and build Blowtorch pre.

Because it does not make sense.
It would not even be close to one Blowtorch.
Just because the ultra level of refinements in every little detail,
just to mention component choice and matching.

But now that you mention it, AndrewT,
this has entered my mind.
That moamp actually has been trying to clone Blowtorch.
Thanks for this dear mate, AndrewT 😉
How good you are.


Lineup
Ps. I had a look at http://www.moxtone.com/ Uskok JFET.
It is a great little masterpiece! Well done moamp 🙂 Ds.
 
However, when you take a large enough sample, you get close. In a few months, sampling 1000 americans will let you predict pretty accurate how the other 150 million or so will vote. It will not predict how an individual person will vote, but how the cohort will vote.

I think that analogy is somewhat misleading. The object of controlled sensory testing in this case is not to see if, on average, people can hear a difference between x and y, but rather can ANYONE consistently hear a difference between x and y. If 2% of listeners could (for example) hear the difference between a polyester and polypropylene capacitor used as a coupling cap in a controlled test, that's something that audiophiles would find significant, but would be lost due to regression when mixed in with the rest of the statistics.

The caution, though, and I know you've already twigged to it, is that the statistics must hold for that 2%. In a group of 1,000 subjects, it's likely that at least one individual scored far better than chance, just from statistics. If that individual can do it when the test is repeated, that's significant. For example, if I score 9/10 in a test where there were 1,000 subjects, it's almost certain that there's someone who scored 1/10. If you retest the two of us and I get 6/10 and my unfortunate counterpart scores 4/10, it's most likely that the first scores were statistical anomalies. This is why we have "confidence intervals, "rather than "certainty intervals."😀
 
SY said:


The caution, though, and I know you've already twigged to it, is that the statistics must hold for that 2%. In a group of 1,000 subjects, it's likely that at least one individual scored far better than chance, just from statistics. If that individual can do it when the test is repeated, that's significant. For example, if I score 9/10 in a test where there were 1,000 subjects, it's almost certain that there's someone who scored 1/10. If you retest the two of us and I get 6/10 and my unfortunate counterpart scores 4/10, it's most likely that the first scores were statistical anomalies. This is why we have "confidence intervals, "rather than "certainty intervals."😀

Then one has to pursue the origin of the idea of that last bit. How was it formulated. The evidence is likely to show that it was a 'judgement call' on the part of the groups, over time, that decided the relevance and design of the parameters of statistical analysis. I'd imagine (although it's not a farm betting statement-merely a question as a point of investigation) it really came down to a postulation by an individual..at it's origin point. I'm not saying it's 'wrong or right'* (the very words themselves* imply a point of judgement call) , but the origins of the point have to be closely considered.

Ie, it might show that with respects to satisfying the monkey inside the human beings who tried to logically formulate the mathematical structuring of statistics..it works out nicely..and 'feels right'..but is it valid? That's the rub. After all, it's an application to the human condition. And in nature--numbers do not exist. That is a human fabrication and tool. Reality, as we like to attempt to express it..whatever it may be.. has no room for numbers. That is a human abstract tool. This must always be remembered and considered, IMHO.

That statistical analysis has invariably (as some tenants and theories of science have) entered the realm of an unquestioned religious experience by some scientifically minded research folk or groups- this begs the question of statistics itself.

As soon as the backdrop becomes unquestioned, veiled by history and rote experience and methodology--then you've got a problem just waiting to explode-a machine that is blinded and headed for a 'running off the rails'...if you will. It's only a matter of time before use and context become invalid. Once again, it is the human in the system that invalidates the idea of logic itself.

This is the exact same path that history, as a concept and record, can and does have. Science can and does easily enter the same condition with regards to issues of that nature. A religious ferverence and reverence for things past as being unquestioned. A massive mistake, as usual. Bloody humans.

As an example (no offense meant) I see a lot of that in some of the posts here in this thread. Those who believe in measurements ruling over human observation... seem particularly susceptible to this as an issue.

If one goes back to the scientific method before Newton corrupted it and placed math first-over observation (THEN theory!!-not before!)-and ruined the idea of advancement in humanity and science..you will find something that is entirely more valid and workable with respects to humans advancing themselves as connected to 'attempting to decode and understand reality'.
 
😉
how about me, John
... what level would you say ... 0.72 maybe 😀

Lineup - happy & content whatever level people put on him
be cause
what do people really know about any body - to be able to judge fairly
in his own Royal Mind he is #1 all categories
and this he has always been .. since him Lineup was born one beautiful day
 
i think the real point is had moamps included this phrase "... that this is my rendering of some basic design principles discussed there not only by the likes of John Curl, Nelson Pass or Charles Hansen but also some of the talented (and largely anonymous) DIYers that invested their knowledge, time and effort to sift the chaff from the wheat ..." in the initial writeup on the site, i strongly suspect many comments that some here have interpreted as thievery would never have been made. the discussions referred to constitute the "legwork" i referred to.

i will reiterate that with all that has been shared in this thread, it is very refreshing to see someone actually built something and likes the results!

also, now having seen someone actually use that volume control idea; i may have to borrow that one myself!

hmmm, there isn't really a devious smiley icon here.
close enough ... 😉

mlloyd1

AndrewT said:
Moamp's reply deserves to be applauded.
His schematic is there for all to see. Congrats for being so open.
Now, having read his reply, why do any of us think he stole J.Curl's Blowtorch design?
 
SY said:


I think that analogy is somewhat misleading. The object of controlled sensory testing in this case is not to see if, on average, people can hear a difference between x and y, but rather can ANYONE consistently hear a difference between x and y. If 2% of listeners could (for example) hear the difference between a polyester and polypropylene capacitor used as a coupling cap in a controlled test, that's something that audiophiles would find significant, but would be lost due to regression when mixed in with the rest of the statistics.

The caution, though, and I know you've already twigged to it, is that the statistics must hold for that 2%. In a group of 1,000 subjects, it's likely that at least one individual scored far better than chance, just from statistics. If that individual can do it when the test is repeated, that's significant. For example, if I score 9/10 in a test where there were 1,000 subjects, it's almost certain that there's someone who scored 1/10. If you retest the two of us and I get 6/10 and my unfortunate counterpart scores 4/10, it's most likely that the first scores were statistical anomalies. This is why we have "confidence intervals, "rather than "certainty intervals."😀


Stuart,

Is that so? I mean, if you would want to know whether your 9/10 score is significant and not a fluke, you would need to design a whole new test done by you, with a statistically large number of test runs, just to test how *you* do this over a large set of samples.

As I see it, you either take a lot of people and look at their average score, or you take one guy and look at his average score.

The first score says something about how average joe (average joe being, say, 100 non-average people) will do the test, the second says something about how you will do similar tests.

I don't think (but am not sure) that it is legal to do a test with a large number of persons and then start to look at a single individual and assigning conclusions to that.

Jan Didden
 
It is a silly and somewhat childish to think or suggest that Moamp stole JC's design. I think he clearly makes his point on his website in a proper and honest way.

The link to his website, posted here, was meant to initiate discussions on a few design topics and to explore (new) ideas. It sadly turned out in a Vendetta against Moamp which of course is sad.

Personally I find his designs and approaches refreshing and informative and truly appreciate the fact that he shares with others in the true DIY spirit.

Franklin
 
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