John Curl's Blowtorch preamplifier part II

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#38,282
john curl said:
When you, PMA, who is known to be 'skilled' at electronic engineering, RFI proofing, and circuit simulation, can also make a 'successful' audio product, independently verified by other experts in the audio evaluation field, then we will welcome you to the 'Society of Successful Audio Designers' like Nelson Pass, Charles Hansen and me, for example. Thanks for all you have contributed, so far.
Click to expand...

Better known from its acronym 'SoSAD'.
 
#38,283
Honestly, I dont care who you are, what you have done, or who you know, this stuff is GOLD on any level!! thanks JN and you too Scott.

John, that you dont seem to care about running through the EMC and thermal design with this man is insane and quite stubborn, especially as your products will have more and more vulnerability to noise in the modern world, with modern devices and as mentioned, dont assume your engineers are up to speed with it.

its quite ironic that you talk of just wanting to share, but when anything threatens to make it easier, or even possible to build, you shun it and start throwing insults around, then change the subject after alluding to its exclusive impossibility.

that you made such a huge deal about these devices being the only possible way and then when work towards a solution to USE them starts 'making sense' you alude to an as yet incomplete cascoded schematic in your mind and say you arent interested anymore.

it has value even as an intellectual exercise for you and your partners for future products, who btw you seem to often conveniently blame for any shortcomings after theve been exposed...

We havent seen any apology for the ridiculous insinuation that JN may not know anything about the different component packaging and device internal structure wrt heat; but then I dont expect to. He has just demonstrated an intimacy with the subject matter that I expect is rarely seen, especially on such a nuts and bolts level for scratch building, so is VERY handy for us solder monkeys without access to a die attach welder and small numbers of high end passivated die samples.

btw vacuphile, SoSAD? HA!
 
#38,287
OK everybody, here is a 'dated' example of how we make line level preamps 'today' rather than 30 years ago. This design, known as the Parasound JC-2, is more versatile and measures better than either the CTC Blowtorch or the JC-80.
Why don't we discuss this schematic, instead of trying to turn a T0-92 into a TO-5?
Always glad to help. '-)
 

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#38,288
john curl said:
OK everybody, here is a 'dated' example of how we make line level preamps 'today' rather than 30 years ago. This design, known as the Parasound JC-2, is more versatile and measures better than either the CTC Blowtorch or the JC-80.
Why don't we discuss this schematic, instead of trying to turn a T0-92 into a TO-5?
Always glad to help. '-)
Click to expand...

Thank you John this is a huge step forward. I think everyone here would like to talk "shop" rather than all the back-biting.
 
#38,290
jneutron said:
Always my pleasure.

EMI was not taught back in the day. It still is an orphan child. It's changing very slowly however. Most my age and older simply have no real understanding.

jn
Click to expand...

Most but not all. Its a specialty field. But there have been a lot of books published and courses available for a very long time. Just depends on what type of systems you are working with whether you will get heavily involved in the subject or not.

I'll be 67 in June. You'll never catch up... I'll always be 10 years ahead. 🙂

-Richard Marsh
 
#38,291
john curl said:
OK everybody, here is a 'dated' example of how we make line level preamps 'today' rather than 30 years ago. This design, known as the Parasound JC-2, is more versatile and measures better than either the CTC Blowtorch or the JC-80.
Why don't we discuss this schematic, instead of trying to turn a T0-92 into a TO-5?
Always glad to help. '-)
Click to expand...

NOW we can move forward and discuss what everyone has wanted to discuss... after the past has been explored... which it has. John, you'll get a lot out of this as well..... more ideas for you to take to the next level.

men (ladies, too)... sharpen your sim's.

Thx-
your old timey friend "Dick" Marsh
 
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#38,292
john curl said:
OK everybody, here is a 'dated' example of how we make line level preamps 'today' rather than 30 years ago. This design, known as the Parasound JC-2, is more versatile and measures better than either the CTC Blowtorch or the JC-80.
Why don't we discuss this schematic, instead of trying to turn a T0-92 into a TO-5?
Always glad to help. '-)
Click to expand...

scott wurcer said:
Thank you John this is a huge step forward. I think everyone here would like to talk "shop" rather than all the back-biting.
Click to expand...

^^ this, indeed every single one of us I dare say. still plenty of 'almost completely' unobtainium, but more easily substituted and nobody can blame you for using the parts you have on hand, its not a public project afterall.

thanks John, I do believe you will get something out of this as well.
 
#38,296
you are welcome to replace any and all gain sections with lumps of permalloy Steve if you so desire 😉

Zener diodes for opamp supplies? I guess there is some secret sauce in the line stage supply net not shown though.
 
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#38,298
Well I feel positively youthful, amongst you older mentors at a mere 52 yrs on this planet.
EMI/EMC is so critical these days, yet quite often on this site I see the phrase "it doesn't matter as this is DIY"😱
Look forward to your discourse on the schematic.
 
#38,299
john curl said:
OK everybody, here is a 'dated' example of how we make line level preamps 'today' rather than 30 years ago. This design, known as the Parasound JC-2, is more versatile and measures better than either the CTC Blowtorch or the JC-80.
Why don't we discuss this schematic, instead of trying to turn a T0-92 into a TO-5?
Always glad to help. '-)
Click to expand...

Is this correct???
Please note very different load resistance (and different location of loading resistors) for +OUT and -OUT. Suspicious parts in green circle.
 

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