John Curl's Blowtorch preamplifier part II - Page 2605 - diyAudio
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Old 12th August 2012, 01:17 AM   #26041
miklos is offline miklos  Canada
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Quote:
Originally Posted by bcarso View Post
miklos, John quite properly withholds at least some details since, among other things, he still may make these. And there are "amateurs" who just want to copy the design and make it, whether they understand it or not.

But there has been more than ample discussion of the salient features, including schematics of related products showing some of the topological approaches, and including some aspects of the power supplies. The problem is you actually have to read the rather long thread
Actually I read about 20,000 of the replies, but thank you for answering instead of John Curl.
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Old 12th August 2012, 01:47 AM   #26042
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Well, Miklos, you should have enough input, especially the first 80 pages from part 1.
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Old 12th August 2012, 01:48 AM   #26043
bcarso is offline bcarso  United States
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Originally Posted by miklos View Post
Actually I read about 20,000 of the replies, but thank you for answering instead of John Curl.
John had stated this, basically, before, when people kept hectoring him for a schematic, so I thought I would do him the favor of a paraphrase. What I could have made more clear is that some people might well attempt to create business of copycat blowtorch preamps, not merely attempt construction of one for their edification and personal use.

I was reminded of a character I knew many years ago, ironically also one who shared the initials, who enthusiastically copied everyone, and about whom we used to joke that he would be a candidate for authorship of one of the "slim volumes" books. That category includes such imaginary titles as Ethical Business Practices, by Kenneth Lay (the Enron guy). In this JC's case (emphatically not John Curl) the title of the slim volume would be My Original Electronic Designs.
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Old 12th August 2012, 01:55 AM   #26044
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Thank you, bcarso. My biggest concern, these days, is to take 'responsibility' for the amateurs who would try to make it. I do try to help with the Levinson JC-2 or JC-3, but THOSE products are buildable by amateurs, because they are more 'forgiving' as to parts selection. I just went through the first 80 pages of part 1. Almost everything is there, IF you are expert enough. If you are not, well it is too much trouble, anyway.
One guy attacked me for making an 'obvious' and insignificant design, yet he started making a clone, that was laughably similar to the Blowtorch. That is what I try to avoid, as well.
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Old 12th August 2012, 02:06 AM   #26045
bcarso is offline bcarso  United States
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Originally Posted by john curl View Post
Thank you, bcarso. My biggest concern, these days, is to take 'responsibility' for the amateurs who would try to make it. I do try to help with the Levinson JC-2 or JC-3, but THOSE products are buildable by amateurs, because they are more 'forgiving' as to parts selection. I just went through the first 80 pages of part 1. Almost everything is there, IF you are expert enough. If you are not, well it is too much trouble, anyway.
One guy attacked me for making an 'obvious' and insignificant design, yet he started making a clone, that was laughably similar to the Blowtorch. That is what I try to avoid, as well.
Exactly John. One is joined at the hip to one's designs no matter how long ago they saw the light of day. And you are considered a bad person if you don't solve all of anyone's problems.

I like the ones who come along and say one's circuit simply doesn't work. Particularly when this judgment is passed based on the results of simulations!

As you say, for those sufficiently sophisticated, the information is there in the beginning of the thread.
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Old 12th August 2012, 02:24 AM   #26046
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Originally Posted by john curl View Post
Thank you, bcarso. My biggest concern, these days, is to take 'responsibility' for the amateurs who would try to make it. I do try to help with the Levinson JC-2 or JC-3, but THOSE products are buildable by amateurs, because they are more 'forgiving' as to parts selection. I just went through the first 80 pages of part 1. Almost everything is there, IF you are expert enough. If you are not, well it is too much trouble, anyway.
One guy attacked me for making an 'obvious' and insignificant design, yet he started making a clone, that was laughably similar to the Blowtorch. That is what I try to avoid, as well.
John, I have found that the unethical will never pay cash, for legal reasons of course.
They will offer to "trade a pair of speakers", or "I will just copy it?

Cheers.

Last edited by Positron; 12th August 2012 at 02:48 AM.
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Old 12th August 2012, 04:57 AM   #26047
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And to their credit they did good testing. But if you need power cords with RF rejection, wouldn't simple shielded mains cable be easier?
A shield would only be affective if the rfi was field-coupled. If it were direct-coupled then a ferrite around the cord would work... for both - just place it close to the equipment. --RNM

Last edited by RNMarsh; 12th August 2012 at 05:00 AM. Reason: rfi on the ac line (cord) --
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Old 12th August 2012, 06:14 AM   #26048
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Yeah, thats what I was thinking. Normal line filtering should be better than what any power cord alone can do.
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Old 12th August 2012, 06:31 AM   #26049
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Actually all that dirt mostly goes through ground loops due to unbalanced interconnects. In professional audio equipment it is non-issue. However, so called semi-professional gear with quasi-balanced, or electronically-balanced ins and outs picks up this dirt, but it is because of flaws of implementation. But if to adopt this approach to consumer audio equipment nobody will buy that multidollar cables.
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Old 12th August 2012, 06:35 AM   #26050
AJT is offline AJT  Philippines
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Originally Posted by RNMarsh View Post
A shield would only be affective if the rfi was field-coupled. If it were direct-coupled then a ferrite around the cord would work... for both - just place it close to the equipment. --RNM
Hi, i am of the belief that noise is best filtered at the source....
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