John Curl's Blowtorch preamplifier part II - Page 3621 - diyAudio
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Old 3rd March 2013, 06:07 PM   #36201
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For the record, in case it is not well understood, I did not stop in my education when I graduated in 1966. I took after-hours courses on servo design (Dr.Dorf), filters (Orchard and Temes) and even a course on IC design, when I was at Ampex.
Later, I took courses at UCB in both undergraduate and graduate analog engineering from R.G.Meyer, and Don Pederson. This is where I got my best insight as to how devices really work. Topology is a separate subject. (It seems to be innate in me)

Last edited by john curl; 3rd March 2013 at 06:35 PM.
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Old 3rd March 2013, 06:19 PM   #36202
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(trust me)
Mr C,

I trust anyone who pumped iron at Venice Beach (or thereabouts)
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Old 3rd March 2013, 06:23 PM   #36203
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I used to run up and down Venice Beach back in 1960, on Dexedrine. My friends told me that I looked like the 'Road Runner' '-)
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Old 3rd March 2013, 06:33 PM   #36204
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Did you ever meet, Big Daddy? (Eric Nord)
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Old 3rd March 2013, 06:53 PM   #36205
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John,
It would be silly to call you on your education and practical experience in the field. That is some of what I was alluding to. Many people go to school just to take classes and never go to get that piece of paper that says I have a degree. Others never set foot on a college but are voracious readers of technical literature and I am sure there are many of those here and in other forums, but that doesn't mean they don't also have massive amounts of practical experience also. I am mostly self taught in my own field of plastics but I must say that at the time I was doing what I was there were only about 50 people in the entire country working in my particular area. I had some of the most educated chemist in my shop with PhD's in chemistry that taught me something and I them as I had the practical experience and more R&D under my belt than they would ever get. They got to theorize and I got to make it happen in a real program. I just got asked to contribute to a University program for advanced composites, not because of any educational background, but because of my actual real life application of some development that I was one of the only people to have ever done. They do not want my knowledge to just be lost, someone else would have to reinvent what I have already done. I have been a seminar speaker in my particular field and the room was full of nothing but engineers from GM, Ford, Hoover Vacuum, Whirlpool and so many others I can't remember. This was because I could talk about something that was not in any text book, it was only in my head and nowhere else. That is why I think that you have such a following here, not for your book knowledge, but for your practical applications in real life. You have been successful with your designs, you have the knowledge and the insights and that is why we are here. To pick your brain and understand what made you do what you did and why if you are willing to share that information. Technical application of data sheets will only take you so far, then the art of the design takes over. It is the little things that make the difference otherwise many designers would have made the same decisions you did, but it is more than that in circuit design, it is the end result that tells the story.

Last edited by Kindhornman; 3rd March 2013 at 06:57 PM.
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Old 3rd March 2013, 07:06 PM   #36206
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Thanks Kindhornman, for your insight. I think of you as highly educated and experienced, but without a great deal of knowledge of hi end audio electrical design. Let's keep our appreciation of each other's developed knowledge and understanding, in order to facilitate better information flow (serious language '-) on this thread.
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Old 3rd March 2013, 09:36 PM   #36207
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Joshua, please note that the graph starts about 8V. That is the 'breakpoint' of many jfets.
Here's a little better illustration:
Attached Images
File Type: jpg 2SK147_exc_gate_current.jpg (231.8 KB, 207 views)
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Old 3rd March 2013, 11:32 PM   #36208
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John,
It would be silly to call you on your education and practical experience in the field. That is some of what I was alluding to. Many people go to school just to take classes and never go to get that piece of paper that says I have a degree. Others never set foot on a college but are voracious readers of technical literature and I am sure there are many of those here and in other forums, but that doesn't mean they don't also have massive amounts of practical experience also........
Kind of reminds me --- Compare; How many electronic course books does one have to read in order to pass electronic courses towards a science degree? A few dozen? Several dozen? One hundred?
And, then how many more books has a practicing engineer read and studied in the 30-40 years afterwards? Several hundred? Several thousands? After basic studies are over, its what you learned and did afterwards that counts the most.
Thx-RNMarsh

Last edited by RNMarsh; 3rd March 2013 at 11:37 PM. Reason: Compare then to now in study time --
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Old 3rd March 2013, 11:50 PM   #36209
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"After basic studies are over, its what you learned and did afterwards that counts the most".

Says the man with the "Q" clearance and all the knowledge that you can never share.
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Old 4th March 2013, 12:04 AM   #36210
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Richard is right. People might quibble that I do not always follow engineering procedures that are supposed to have been instilled in engineering school.
It has been done before.
Except for math, I learned most of my design of electronics working with people who WERE full engineers, and who showed me how to get to the 'essence' of a problem, rather than do a thesis on it.
Let me give everyone an example: About 40 years ago, or more, I was taking one of those engineering classes at UCB, and just before class started, I was with several other students, who were looking over their homework for the class.
One guy looked at this whole page of math and stated: "I understand everything, but this factor of 10" I glanced at his calculations and said: "That is gain of the jfet stage that we are analyzing, you know, GmR(load)." The student had lost the 'forest' by just looking at the 'trees'. That's the sort of insight you gain when you have spent a number of years working on designs in industry, before attending that particular class. '-)
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