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Old 8th June 2010, 06:32 PM   #4621
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Quote:
Originally Posted by 1audio View Post
This is an issue of much debate. The classic a weighting of the noise floor was called into question by Dolby,

The number mentioned above is more of a dynamic range number than a s/n number I think.
Demian,

To me weighting is a valid but different issue. Noise and the masking it causes are s/n related. How we perceive it is different.

I have problems comparing a sine wave to broadband signal.

When you have a multi-tone or multi-band signal the energy rises depending on how the signals combine. If there is no relationship between the signals it is typically the square root of voltage. For many musical signals where there is a harmonic relationship the signal combination can be greater than this.

So if the issue is picking signal or distortion out of noise then I think that the bandwidth of the hearing mechanism comes into play.

As the issue was phonograph records, I used the 20db clip level. When you cut grooves in a master if you overmodulate the consequences are severe. The groove wall goes to zero and you start all over again!

Low frequencies are the problem area. Cutting a master still requires artistry.

The point is that there is a reason why some s/n calculations which are based on good math do not reflect the results. By leaving out other conditions they have an inaccurate comparison.

ES
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Old 8th June 2010, 10:13 PM   #4622
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Quote:
Originally Posted by john curl View Post
Well, at last some useful input. Allen, have you made the comparisons between amorphous and mu-metal, yet, yourself? I have been fighting with myself with that decision. Is that why there are two almost identical Lundahl transformers in its catalog for highest quality MC cartridge transformers?
John, yes, I have tried both regular and amorphous cores in otherwise identical output trafos, and to my ears, the amorphous sounds MUCH better, with MUCH better low level detail that the standard core seems to "ignore".

So I would assume that in a MC input trafo, the differences would be even more marked. But as prevoiusly stated, I'm not even interested in trying.

But amorphous has two disadvanatges: 1/ it's way more expensive, Lundahl AM trafos are twice the price of an otherwise identical regular trafo, and 2/ maximum core saturation magnetic level is halved over regular cores.

Quote: Stick to your opinion, on transformers and audio reproduction requirements, Allen. You and I work in rarified atmosphere of high end audio design. We HAVE to work with phono cartridges like the Lyra Titan, or even more exotic, because that is what OUR customers have or use. We also have to load them very accurately, because that is what our customers demand. (quote)

Exactly.

(quote) Many designers are impugned on this website for the the articles they have written on audio quality. So far 3 Ph'd's with University and research lab experience that been 'picked at' on this tread alone. This includes: Hawksford, Otala, and VandenHul. Why? If what they wrote in their articles decades ago was so awful, why not a huge protest at the time? At the same time, why do these Professors (at least at one time in their lives) not back down and correct their work? I know each of these people personally, and I always learn from them. Sometimes they learn (a little too much) from me, and I find my topologies used or discussed to others, by them. In any case, I have asked them point blank about any controversies and they have never backed off, even to me. Who are these 'critics' who don't teach engineering, publish papers in the field of audio design, or know or significantly correspond with the people they are impugning? What are they up to, and why do they do it? (quote)

Because unfortunately, like it or not, a small percentage of the population are shitheads, and a key behavoural trait of them is attempting to shoot down true masters, possibly in an bid to make themselves look bigger.

I love associating with a true master from any field and I always gain something positive from the experience, be they a surgeon, a chief, a race car driver or an electronics wiz.

Regards, Allen
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Old 8th June 2010, 11:48 PM   #4623
jcx is offline jcx  United States
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I see our masters (in their own minds) want to have it both ways - articles by phd researchers in peer reviewed journals that reexamine Otala and come to different conclusions can be criticized and dismissed because they didn't publish their analysis Before Otala brought the issues up
or you can "demolish" criticism of assumptions and relevance with insistence that the "the math is correct" (when done by your guru but not other's) or that a "Cabal" suppressed publication and drove out your heroes or other irrelevant personal attacks

some of us are practicing engineers trying to use our education's and experience' intellectual tools to sort through published claims, analysis and wild assertions to understand and design better circuits

I like learning more about obscure points of low noise design - I get really tired of the constant retreat to personal attacks, appeals to off line, unpublished "authorities" claims of persecution and other “black bag” rhetorical tricks in response to any questions

Private “Mastery” echoing to medieval Guilds is not how the electronic tools and devices we use have come about or how technology is advanced in the modern era - if you haven't noticed it is by publication, criticism, reformulation, proposing falsifiable hypothesis, publishing reproducible test results in a public arena

I would hope some here could "master"" honest intellectual interaction and loose the constant personalization of calculable, testable, often well documented engineering principles and their applications

I don't dismiss “Mastery” - long practice, genetic gifts, unique experience, knowledge that has been passed by personal contact is still important but your best service to the future is to publish, debate, show how to test and verify to turn this “mastery” into accessible engineering knowledge

Last edited by jcx; 8th June 2010 at 11:54 PM.
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Old 8th June 2010, 11:55 PM   #4624
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[QUOTE=Allen Wright;2211119]John, yes, I have tried both regular and amorphous cores in otherwise identical output trafos, and to my ears, the amorphous sounds MUCH better, with MUCH better low level detail that the standard core seems to "ignore".

I am using an amorphous core AVC attenuator (line level) and can tell you it resolves low level information much better if a hf AC "bias" voltage is applied to it. Allen I think you know what I am talking about here.

Rob.
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Old 9th June 2010, 12:19 AM   #4625
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Quote:
Originally Posted by Allen Wright View Post

But as prevoiusly stated, I'm not even interested in trying.
I said that once, too. Then I finally overcame my prejudices and actually tried it. But hey, I'm probably one of those ****heads you were talking about.
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Old 9th June 2010, 12:44 AM   #4626
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Mmmm... it seems to me that people, Phd or not, make various contributions at different times. Some people are prolific, others make a single breakthrough, others a body of (lesser?) work.

The extent of modern knowledge on any topic, this one included is not held by any one person or even by a group of people. In reality some aspects of information are held privately, not disseminated at all - for various reasons.

This should be somewhat obvious by the nature and scope of the expert comments in this thread. The full scope of information is too large for any one person to be possessed of it all.

As far as revisiting earlier work, few if any do, unless they have made a significant new improvement that relates directly to the earlier work. The typical modus operandi of the published Phd is to let others carry the work forward, IF that happens - and those who do publish their contributions.

(...the only place that one might find a commentary on earlier work by those persons is typically in a private discussion or maybe in a public speaking engagement...)


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Old 9th June 2010, 12:46 AM   #4627
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Quote:
Originally Posted by jcx View Post
he also just "pulls out of his hat" a number for the quantization "sampling time"
You're too kind. This is another case of fuzzy thinking. To be fair the whole thing is presented as a thought experiment and has no place as a "refereed scientific article", more an evening at the blackboard.
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Old 9th June 2010, 07:46 AM   #4628
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Default Engineers' duel

Without comments. I'm sure you'll forgive me the OT

jd
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File Type: gif dilbert duel.gif (96.5 KB, 250 views)
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Old 9th June 2010, 07:51 AM   #4629
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OK, I'll make up for it:

PlanetAnalog.com - Strengths and weaknesses of common resistor types

I send you one link !

jd
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Old 9th June 2010, 02:22 PM   #4630
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Quote:
Originally Posted by Allen Wright View Post
So far 3 Ph'd's with University and research lab experience that been 'picked at' on this tread alone.
The Institute for Creation Research

"The central core of ICR's mission is scientific research, which formed the basis of our founding in 1970 by Dr. Henry M. Morris. A respected scientist in his own field of hydrology, which led to the publication of The Genesis Flood in 1961, Dr. Morris saw clearly that good science—the proper handling and interpretation of scientific evidence—would demonstrate the veracity of the biblical accounts of Creation and the Flood."
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