John Curl's Blowtorch preamplifier part III

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When I discovered AES, a long time ago, participating in a one week HIFI show in Paris, I thought it was a kind of an official organisation governing this activity in U.S.. I quickly realized that it looked more like a gentleman club. Rotary or Lions like ;-)

There is blatant commercialism at AES conferences almost as bad as a CES, this is strictly forbidden at any IEEE conferences. In Vienna in 1992 Philips and Sony had gorgeous models handing mini-disk players to people to sample a listen, they sounded like scheit.
 
AES convention papers are not considered peer reviewed. Almost anything gets in.

They do have stringent requirements regarding syntax, grammar and so on... :)

... I quickly realized that it looked more like a gentleman club. Rotary or Lions like ;-)

Yes, ties all over the place, very few of the long hair/denim type.
Nevertheless, there are (were?) interesting presentations once in a while to make the trip worthwhile.
 
Of course. The first thing to verify before to accept the conclusions of an experiment is to verify that the conditions of an experiment lead correctly to its conclusions. IE, not other external phenomena can explain the results observed.
Tell that to Markw4 when he posts claims of DAC sound differences because he won't reveal how the listening test was set up despite telling us to try it.
 
On my side, I pretend nothing, and surely not any "superior knowledge",
Really? Then what's with your post quoted below?
We, professionals (IE people that work in it for their living) , are the priests of what you imagine is a religion. And, to be totally sincère, because we are not all so naive, and because we know what happens in the sacristy, we don't believe too much in this religion. We listen with amusement and interest, and more or less sympathy, when a confrere preaches during the Mass. ;-)
 
The important thing to remember is that you don't get a second chance. You must miss the ribs but push deep enough to reach the heart. It's usually recommended to place the weak hand flat against the back, as possible, and to locate the entrance hole by feel. At this point you have an angry and very motivated human being, the most dangerous mammal on this planet. Maybe best to shoot them first, then proceed.


Good luck and be careful!
Chris
 
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I came upon a video on YouTube of lion attacks on humans.

The penultimate one was the worst. Some guy caught in a cage, blood everywhere and another guy on the outside holding onto the victim through the bars pleading with someone to find a policeman with a gun that could shoot the lion. Eventually the lion won the tug of war and got the guy by the neck and shoulder. The video cut at that point. Horrific.

My bit of blood and guts to start the day.
 
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I'd like to think that if it came to that (I was dumb enough to get into a cage with an enslaved lion) that I'd choose to save the lion's life over mine. I'm old and the world's full of people. But nobody knows how they would react in a crisis, almost irrespective of how they think they're prepared.


Folks who routinely carry firearms say that amateurs train until they get it right, professionals train until they can't get it wrong. But it's not really even remotely true. We all still make moral judgements, real-time, and that can't be trained for.


Weird turn there, sorry, all the best,
Chris
 
AES convention papers are not considered peer reviewed. Almost anything gets in.

The AES changed their policy wrt convention papers around 2002-2004; newer convention papers are getting kind of a "peer review light" which means that the abstract and an extended precis is reviewed by at least two anonymous reviewers.

But that doesn't (shouldn't) mean, convention papers aren't worth a read. If one knows a bit about scientific methodology and the topic covered, he should be able to figure out if it is a sound publication or not.

Otoh the peer review process can't ensure that a published article about observational research is correct, or does not contain errors. The reviewers role is to help the editiors in the decision if the paper is of interest for the readership, if it is clearly stating the objective, methods and results and further does not violate basic scientific principles (like missing references ) and includes no really obvious methodological flaws.
 
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The interesting point about the role of the Ashihara/Kiryu paper in this context seems to be that there is nothing really new in it.

Basically they've confirmed that humans can detect IMD products - not harmonically related to the content in the audio band - at a level of ~55 - 60dB below the signal level (in the audio band).
And they've confirmed that a loudspeaker carrying two or more signals in the band above 20 kHz can/do produce IMD products that might fall in the audio band (if reproduced above a certain level).

Nevertheless it is constantly presented as the ultimate "rebuttal" of Oohashi et al.'s findings.
They used different speakers than Oohashi et al., they used different signals, they used different levels (above the levels reported by Oohashi et al.) and they did not test the two loudspeaker conditions (one for the audio band and one for the ultrasonic content) that was used in the Oohashi setup.

So the "rebuttal assertion" is a bit....strange.
 
Apart from the questionable setup with separate Tweeters for the ultrasonics, ....

Could you explain,why the setup was questionable. Up to now in this thread the incorrect assertion was maintained that Oohashi et al. did not use a seperate tweeter.

..... big objection that I have against this Oohashi experiment is the used DSD format, which is OK for storing music in large libraries, exactly the reason why it was invented by Sony in the first place.

But several AES papers have shown that this format doesn’t allow for editing the music without damaging the content.
And in Oohashi’s workflow, lots of editing steps have been taken.

Could you point to the "lots of editing steps" ? I must have missed the description.

To validate a discovery, it is mandatory that the test can be replicated by others to become generally accepted. To my knowledge this has never been confirmed.

Hans

In fact there were several follow up studies who could find also corrobation for the Oohashi et al. results.
Others could not, but the main difference between the experiments was often just, that the positive results came from studies who really tried to replicate/reproduce the Oohashi experiment by using quite similar setups and methodology wrt stimuli used and the addtional imaging processes.

The experiments with negative results often used vastly different setups and methods and did not use Pet-Scans or EEGs.
 
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Demian,

The miniDSP referred to earlier was -HD version.

Opamps on in and out, polar cap coupled. I shorted/bypassed input polar caps

The 2608 opamps (3) are located on the bottom.

No visual HF filter but will test on opamp output to be sure with so many tiny parts.


82558945_837787326670715_8356551497974022144_n.jpg


-THx-RNMarsh
 
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