is there any critic of negative feedback that knows Bode's Integrals?
wrong on several counts
fundamental feedback limitations, the realities of audio amplification/playback
could add criticism of Kunchur's methods, interpretations too – not exactly mainstream psychoacoustics yet
loop gain corner frequency "minimum phase" "delay" is not transit time as used by device engineers
for the quantity limiting negative feedback application we're talking "excess phase"
“transit time” is true delay - irreducible by linear compensation
linear compensation (as in feedback compensation) works fine for the “minimum phase” portion of loop gain
the true, irreducible delay, “transit time” for electronics, modern audio power devices can be 10s of nanoseconds - can be even less for MOSFET - limited in some by the leads, trace lengths
for the complete feedback amplifier with often 2nd order response and few hundred kHz corner the linear delay of audio frequencies is ~ 1 us
additionally you listen to the same design, model power amps in R,L channels – so any “interesting time errors” would have to be in the differences between the 2 channels – any common “time delay” is equivalent to starting the recording a microsecond later, or leaning back ~0.01 inches
wrong on several counts
fundamental feedback limitations, the realities of audio amplification/playback
could add criticism of Kunchur's methods, interpretations too – not exactly mainstream psychoacoustics yet
loop gain corner frequency "minimum phase" "delay" is not transit time as used by device engineers
for the quantity limiting negative feedback application we're talking "excess phase"
“transit time” is true delay - irreducible by linear compensation
linear compensation (as in feedback compensation) works fine for the “minimum phase” portion of loop gain
the true, irreducible delay, “transit time” for electronics, modern audio power devices can be 10s of nanoseconds - can be even less for MOSFET - limited in some by the leads, trace lengths
for the complete feedback amplifier with often 2nd order response and few hundred kHz corner the linear delay of audio frequencies is ~ 1 us
additionally you listen to the same design, model power amps in R,L channels – so any “interesting time errors” would have to be in the differences between the 2 channels – any common “time delay” is equivalent to starting the recording a microsecond later, or leaning back ~0.01 inches
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hhhhmmmmm....have you published anything about designing in the likes of Cordell, Jung, Pease et al......? i am eager to see it.....i am a novice eager to learn....
Really Tony. Might check out my White Papers.
SAS Audio Labs, amplifier preamplifier design problems
and the pages that follow.
I have discussed capacitor problems with Walter Jung. I have also discussed problems with a scientist who worked at FermiLab etc, worked in the lab at a local college, helped professors at the local college and senior engineering students at College.
Is publishing all that important? Could be, may be not. I know of at least two major publications whose authors have been witnessed falsifying data, altering their resume etc (Federal Investigator). I have witnessed reviewers who destroyed my equipment because I would not "give" away a component to them. They publish, and are professionals credentials.
Here is an article you might be interested in reading. Martin DeWulf, criminal defense attorney, editor of Bound for Sound. It discusses the publishing industry and forums content.
Sample Reviews
Cheers.
now we are getting there......John Curl has a written article culled from his postings here....it is convenient to go back to it every now and then....
it is important to have something written down somewhere.......helps to understand the author better......
TBH, i do not give so much weight to reviews.....but they make great entertainment....
Below is some explanation of JCX's comments.
I suggest the public read the comments from Dr. Kunchur at the end of this post. He includes not only scientists from other universities, peers, but also from third party, three national organizations. Here is a partial quote. Obviously JCX needs to correct his errors.
"(but no controversy whatsoever in all the professional circles, which include audiolists, otolaryngologists, acousticians, engineers, and physicists )."
Also:
"After that the results and conclusions were presented at conferences of the 1) Acoustical Society of America (ASA),
2) Association of Research in Otolaryngology (ARO),
3) American Physical Society (APS). Seminars were also made at numerous universities and research/industrial institutions (please see the list on my web site).
As one can see, Dr. Kunchur presented to third party experts in the field, and national organizations. He includes more at the end of this post.
The rest of JCX's comments are inconsequential as we are dealing with transit times, the time it takes any signal to "travel" from input to output, regardless of frequency.
Now for Dr. Kunchur's comments. (I have permission to publish such.)
(but no controversy whatsoever in all the professional circles, which include audiolists, otolaryngologists, acousticians, engineers, and physicists ). An experiment has to be carefully thought out and then submitted as a proposal to an Institutional Review Board (IRB) and approved by them before it can even begin.
Then optimum equipment, methods, and a multitude of cross checks has to be developed (if you read my papers in their entirety, you will appreciated what went in).
The results, analysis, and conclusions are then carefully considered and discussed with colleagues who are experts in their related interdiscplinary fields; for this I went in person to various universities and research institutes and met with people in departments of physics, engineering, psychology, neuroscience, music, communications sciences, physiology, and materials science.
After that the results and conclusions were presented at conferences of the Acoustical Society of America (ASA),
Association of Research in Otolaryngology (ARO), and
American Physical Society (APS).
Seminars were also made at numerous universities and research/industrial institutions (please see the list on my web site). After each presentation, the audience is free to tear apart the conclusions and ask all possible questions. Eminent people such as presidents of the above mentioned societies and corporations (ASA, ARO, Bose corporation, etc.) have been present during my presentations.
After passing through this grueling oral presentation process, written manuscripts were then submitted to journals. There, anonymous referees are free to attack the submission in any way they want. More than a dozen referees and editors have been involved in this journal refereeing process.
Only after everyone is satisfied with the accuracy of the results and all statements made in the manuscript, are the papers published in the journals. The entire process took around 5 years from initial concept to refereed publications.
As one can see, Dr. Kunchur took great pains to include all experts in the field of endeavor to back him up.
As far as 10ns etc, an oscilloscope will demonstrate that nearly all audio amplifiers have a transit time much much much greater.
Cheers.
I suggest the public read the comments from Dr. Kunchur at the end of this post. He includes not only scientists from other universities, peers, but also from third party, three national organizations. Here is a partial quote. Obviously JCX needs to correct his errors.
"(but no controversy whatsoever in all the professional circles, which include audiolists, otolaryngologists, acousticians, engineers, and physicists )."
Also:
"After that the results and conclusions were presented at conferences of the 1) Acoustical Society of America (ASA),
2) Association of Research in Otolaryngology (ARO),
3) American Physical Society (APS). Seminars were also made at numerous universities and research/industrial institutions (please see the list on my web site).
As one can see, Dr. Kunchur presented to third party experts in the field, and national organizations. He includes more at the end of this post.
The rest of JCX's comments are inconsequential as we are dealing with transit times, the time it takes any signal to "travel" from input to output, regardless of frequency.
Now for Dr. Kunchur's comments. (I have permission to publish such.)
(but no controversy whatsoever in all the professional circles, which include audiolists, otolaryngologists, acousticians, engineers, and physicists ). An experiment has to be carefully thought out and then submitted as a proposal to an Institutional Review Board (IRB) and approved by them before it can even begin.
Then optimum equipment, methods, and a multitude of cross checks has to be developed (if you read my papers in their entirety, you will appreciated what went in).
The results, analysis, and conclusions are then carefully considered and discussed with colleagues who are experts in their related interdiscplinary fields; for this I went in person to various universities and research institutes and met with people in departments of physics, engineering, psychology, neuroscience, music, communications sciences, physiology, and materials science.
After that the results and conclusions were presented at conferences of the Acoustical Society of America (ASA),
Association of Research in Otolaryngology (ARO), and
American Physical Society (APS).
Seminars were also made at numerous universities and research/industrial institutions (please see the list on my web site). After each presentation, the audience is free to tear apart the conclusions and ask all possible questions. Eminent people such as presidents of the above mentioned societies and corporations (ASA, ARO, Bose corporation, etc.) have been present during my presentations.
After passing through this grueling oral presentation process, written manuscripts were then submitted to journals. There, anonymous referees are free to attack the submission in any way they want. More than a dozen referees and editors have been involved in this journal refereeing process.
Only after everyone is satisfied with the accuracy of the results and all statements made in the manuscript, are the papers published in the journals. The entire process took around 5 years from initial concept to refereed publications.
As one can see, Dr. Kunchur took great pains to include all experts in the field of endeavor to back him up.
As far as 10ns etc, an oscilloscope will demonstrate that nearly all audio amplifiers have a transit time much much much greater.
Cheers.
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Ok... that seems like a good enough examination of the subject..... can we also relate his results to any other tests.... such as harmonic structure or feedback or ??? And, can we reduce the transit time... how?? Thx, RNM
Then what does this statement mean?
"the realities of audio amplification/playback could add criticism of Kunchur's methods, interpretations too – not exactly mainstream psychoacoustics yet "
Cheers.
I asked an innocent question of the background of Morgan Jones. I could not place him, because he apparently writes books about tubes, and I don't use them enough to order any recent book on them.
Still, tubes did NOT suffer the TIM or slew rate problems that solid state suffered, until we speeded things up. What is the difference between tubes and solid state?
How about 20dB feedback with a 10KHz open loop bandwidth (tubes)
Or about 60dB feedback with a 100 Hz open loop bandwidth (solid state)
Same or different?
Still, tubes did NOT suffer the TIM or slew rate problems that solid state suffered, until we speeded things up. What is the difference between tubes and solid state?
How about 20dB feedback with a 10KHz open loop bandwidth (tubes)
Or about 60dB feedback with a 100 Hz open loop bandwidth (solid state)
Same or different?
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John, that's phase delay, not transit time. To show the difference, hook up a slow opamp (a 741, for example) as a unity gain follower- if the transit time were 10us, you'd see the delay in the output, otherwise causality is violated, right? You don't. Now you DO see delay in the rise open loop because of the dominant pole, but if you zoom in, you can see that the output begins to rise almost instantaneously following the input.
Different, but not because of the devices. I thought you had studied basic control system theory, but perhaps not?
As far as the knock on 'The Radiotron Designer's Handbook' It was a true masterpiece for its time, from perhaps 1940-middle '50's. This book grew every year, and was a true industry 'bible'. I have never found such a complete book on audio design in the last many decades. Any recommendations, anybody?
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