John Curl's Blowtorch preamplifier part II

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Damage the silicon at the lattice level. reduces gain, increases leakage...TRR speeds up. (a bit similar to ion implantation to introduce lattice defects for recombination).

As a side effect, makes the circuit a bit more reliable in a radiation enviro.

jn

Funny just this week a private satellite company asked for some rad hard AD524's from 1982. There actually were some 4" wafers in die bank.
 
I was originally surprised that they used the uA741 as an example, since it had been out for perhaps a couple of years, as I had used them back in '69 for servo control.
Unfortunately the 741 is one of the very, very few opamp circuits publically available that is modelled 'correctly' in Spice - the pseudo models easily available will lead one astray; an interesting exercise is to examine the PSRR of a real circuit used in various configurations - surprise, surprise!! ... it does not behave like the usual simplistic concepts would suggest ...
 
Unfortunately the 741 is one of the very, very few opamp circuits publically available that is modelled 'correctly' in Spice - the pseudo models easily available will lead one astray; an interesting exercise is to examine the PSRR of a real circuit used in various configurations - surprise, surprise!! ... it does not behave like the usual simplistic concepts would suggest ...

Really Frank let go of it your trolling is getting tiresome.
 
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Well, pardon me ... I thought the point of having audio discussion forums is having a venue where people can put forward points of view about what is necessary to achieve higher standards of sound. If the tools and techniques that are typically used have issues, have weaknesses which are generally not mentioned then what is happening is that one's ability to understand "everything" is downgraded - I was not aware of the interesting PSRR behaviour until I tried the exercise for myself, I didn't see it mentioned anywhere, it's not obvious to find in the literature. Is the aim of the game to have only the specialised knowledge people the repositories of key information that could make all the difference, making it less accessible to everyone else?
 
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Damage the silicon at the lattice level

Thanks. (what is TRR?)

Radiation hardening - Wikipedia, the free encyclopedia



Funny just this week a private satellite company asked for some rad hard AD524's from 1982. There actually were some 4" wafers in die bank.

Keep some for building RIAA preamps when we’ll move to Mars :D

RHA - Radiation hardness assurance (Serious job)
Test per MIL-STD-883F
METHOD NO. ENVIRONMENTAL TESTS
1017.2 Neutron irradiation
1019.6 Ionizing radiation (total dose) test procedure
1020.1 Dose rate induced latchup test procedure
1021.2 Dose rate upset testing of digital microcircuits
1023.2 Dose rate response of linear microcircuits
METHOD NO. MECHANICAL TESTS
2020.8 Particle impact noise detection test

Spec’d to MIL-PRF-38535(?)

George
 
I notice the name Ohno keeps coming up in exotic wire blurbs. Is Ohno involved in the audio business or does his research get used in real scientific applications, or both? Is Ohno ambivalent or oblivious and the audio companies simply taking advantage of his research?

This page actually has what appear to be images of the copper crystals, I was thinking if they are real they must be available from a research paper by this person.

FIMpression "solid-core" UP-OCC Mono Crystal Wire
 
I notice the name Ohno keeps coming up in exotic wire blurbs. Is Ohno involved in the audio business or does his research get used in real scientific applications, or both? Is Ohno ambivalent or oblivious and the audio companies simply taking advantage of his research?

Atsumi Ohno was a metallurgy researcher, wrote a few books, and patented a copper casting process. I don't know if he's still alive, but if he is, he's quite old. No personal involvement in the fashion audio business AFAIK. I suspect that since his casting process has mostly been used in serious applications, he would not have a great awareness of the fashion audio use of his name as a sales point.

In fashion audio, Japanese names seem to be highly favored; there's a dissertation in marketing or psychology waiting there for an enterprising student. In any event, "special process," "Japanese scientist," it's a honeypot for the cable peddlers.
 
Atsumi Ohno was a metallurgy researcher, wrote a few books, and patented a copper casting process. I don't know if he's still alive, but if he is, he's quite old. No personal involvement in the fashion audio business AFAIK. I suspect that since his casting process has mostly been used in serious applications, he would not have a great awareness of the fashion audio use of his name as a sales point.

In fashion audio, Japanese names seem to be highly favored; there's a dissertation in marketing or psychology waiting there for an enterprising student. In any event, "special process," "Japanese scientist," it's a honeypot for the cable peddlers.

Dr. Ohno received his PHD in 1963 from U of T (Toronto) as of 3 years ago he was involved with a company that was casting copper by his method (Furukawa Electric of Japan) but not audio cable directly AFAIK . His book Solidification – The Separation Theory and its Practical Applications . available in english language translation is the book on the process. http://www.audiosensibility.com/information_links/OCC_ResearchPublication.PDF is a link for his process.
Far more than just buzz words from a PHD with a number of patents on the matter. the most quoted of these patents Patent US4605056 - Process and apparatus for the horizontal continuous casting of a metal molding - Google Patents .
I have several sets of the furutech cable to my ears they sound good . :drool: For him to have made a good some of money off the patents to me says it is a lot more than "snakeoil" in a number of applications . I know for some that no evidence of OCC worth . As Mark Twain said the truth does not have to be believable it the truth . A story however does need to be believable. Or word to that effect. Regards:(
 
Dr. Ohno received his PHD in 1963 from U of T (Toronto) as of 3 years ago he was involved with a company that was casting copper by his method (Furukawa Electric of Japan) but not audio cable directly AFAIK . His book Solidification – The Separation Theory and its Practical Applications . available in english language translation is the book on the process. http://www.audiosensibility.com/information_links/OCC_ResearchPublication.PDF is a link for his process.
Far more than just buzz words from a PHD with a number of patents on the matter. the most quoted of these patents Patent US4605056 - Process and apparatus for the horizontal continuous casting of a metal molding - Google Patents .

OK, so pretty much what I said. Yes, he's real. Yes, he's written some books and gotten some patents. And no, he's not involved in the fashion audio business or with audio cable scammers.
 
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