John Curl's Blowtorch preamplifier part II

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I am pretty new here, but audio has been a big part of my life.

I find the nature of the discussion pretty kindergarden. Someone designs amps for many years that are considered to be very good and a bunch of engineers with an axe to grind take shots. Hmmm, what is supposed to come out of the discussion? Are we supposed to take sides? Can we make products better by subtraction? If a JC or CH only did what other engineers told them, would they have been as successful? My experience is that you need to run with YOUR own personal dream. If enough others share it on the way, then you have made some kind of positive mark - bravo!

Getting back to the bit-perfect argument. If some are content that we have reached utopia and repeatability, then they should rejoice in being able to focus their creative juices on finding better wine (golf clubs, speakers, beer, cars.......). For those with question marks, please continue to move the "art" forward even if the science is a bit slow.

What have I learned in this thread? That one of the major accomplishments of the civilized world is sorely lacking among many of the learned. Tolerance. Audio is as much of an art as it is science. Beauty is in the eye and ear of the beholder. There is plenty of room on this planet for differing approaches. I am a professional trumpet player. We have the same types of arguments, and the same lack of concensus. Still, great music is being made by those doing it more and talking about it less.

What I also learned it that in a thread with 1200+ posts, even the learned do not have more than 100 posts worth of any significant information other than their personal problems. I find John Curls anecdotes refreshing. He makes no claims to having THE ultimate answer and freely shares his mistakes. More entertaining than frustrated mathematicians..........
 
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Thanks, Rowuk. You have it right.
I am just a 'semi-retired audio designer trying to convey some helpful points to other audio designers. It doesn't pay, except when someone learns something new. My anecdotes are based on my own personal experience, often changing my personal direction of audio design. Feedback? I used to believe in the more the better, especially 40 years ago, and more. You should see what I used to do, then, truly believing that negative feedback could fix just about anything. I just found that professional musicians, like some members of the Grateful Dead, rejected my efforts, at least at first. It is NOT that they disliked me, or what I was doing, they NEEDED my efforts in order to save time, money, and hassle. They just had to be 'honest' with what they were evaluating, whether it was designed by me, Dick Burwen, Dolby, or any other manufacturer. That is how I learned what worked, and what didn't work, and I got made famous from those results, not by marketing or internal influence, etc., but I have found since 1973, that certain design approaches work. and other design approaches don't work as well. Tubes for example, often work, and for the very same reasons that many of my solid state products work. There is really little difference, in basic principles. Yet I am attacked when I promote lower negative feedback, high open loop linearity designs, etc. Why? Perhaps someone will give me a reasonable response. I just hope that I can respond in kind, and not be censored as I often am, as I am under PERMANENT moderation, apparently because I just might hurt someone's feelings with a strong response.
 
John's anecdote is a perfect example- he used an op amp at the input of one of his high end products. The magazine writer saw it, decided that this compromised the sound (there's no indication that he tried to verify that there was actually a sonic detriment), and wrote a negative review. You'll never see John (or by extension, Charles) try that one again! That is indeed a cultural violation that will cause the "high end" license to be suspended.
Is there a link somewhere for that review?

John

I didn't think so. That story did sound a little fishy to me.

John
 
I can't be bothered to do the maths in detail, but assuming the input Vi does not get too big (say, |Vi|<1) then the distortion terms are small so the only significant 'Baxandall' order multiplication terms will come from the first set of multiplications. The feedback will then roughly reduce distortion by 100.
Vo ~ 10 x (Vi + .0001Vi^2 + .0002Vi^3 + .000025Vi^4 + O(5) )

If Vi gets large, then the higher order terms would be significant and the algebra would get messy. I'm too old to do messy algebra!

Ah but it is the small terms that are the game we are after. I don't mean anything personal by this, but this was supposed to be an easy math problem!
 
It's all MY fault, everybody. Every underemployed individual can and will criticize me here. If I complain about it, it is my fault. If I bring up something new, it is my fault. If my associates tend to make audio products that can't be PROVEN with double blind tests to work differently than anything else, it is my responsibility for having them as colleagues. And so on, and so on! '-)
 
With all due respect

Mr.Curl did not start the thread so does not have ownership of it...........you could ignore him( a simple solution)..........but in his defense there seems a particular group that goes after him regardless, incessantly at that. If you disagree state you opinion and engage a discussion, if no conclusion is reached move on.

I am starting to feel that posting of cartoons (which I have been guilty of in times past) is more fruitful than this Bybee diatribe which attract trolls that suddenly appear out of the woodwork, invariably the same ones I might add.

Jam
 
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