Of interest, I have output stages using complementary 2SK82 2SJ28 SITs as
followers which show the following distortion curve:
😎
followers which show the following distortion curve:
😎
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Joined 2009
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Sounds wonderful. We shall have to hope that it will make commercial sense for you to offer them for sale to this community...
With high voltage rating a p-type device might allow tube fans to make complementary circuits for the first time.
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That's right folks, design today with yesterday's parts, for tomorrow's products! 😀
Bigun, this stuff is mostly unavailabium...
_-_-bear
Bigun, this stuff is mostly unavailabium...
_-_-bear
Steve, I shall try to get 100pcs of KP903A, it could take 1 month, if successful, I could send this parcel to you, and you could distribute them among the interesting guys.
Thank you, Vladimir!
Would it perhaps be easier for your Russian friend to get them and just send them directly?
se
Yes, but if the friend not agree, I shall ask persons who go to Moscow for a business from Tashkent.
Came across this Russian forum thread. Seems to be a LOT of talk about the KP903A, along with a few schematics, including what appears to be a KP903 Circlotron.
GtLab.Net - Ïå÷àòàòü ñòðàíèöó
se
GtLab.Net - Ïå÷àòàòü ñòðàíèöó
se
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Joined 2009
Paid Member
I figure there are already more great sounding proven amp designs based on parts we can buy than I have time to build and listen to, that I don't worry about unavailabium, but it's all part of the fun! You see how the fever starts with the prospect that somebody found the special unknown vacuum tube from an ex-military factory nobody heard of that's dirt cheap because they are being smuggled out on the black market and of course they sound fantastic - then the fever builds and everyone wants them, the prices rise, some profits are made - and eventually the fever dies back down again. I have a dozen germanium transistors and two dozen unobtanium nuvistors I got for a buck each because of this fever which will let me build the best sounding amp 😉 (there's a bit of this fever over old speaker drivers too) But it's fun and I'll take a bunch of these JFETs if somebody can get a GB going.
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I wonder what makes this part so exciting compared to, say, a LU1014 which can still be hade for < USD3, matched ?
Patrick
Patrick
Personally, I really like the 20pF input capacitance. The LU1014's 1,147pF is rather a deal killer for me.
se
se
se
se
Please read Nelson Pass's article on Zen Version 9 on how to operate the LU1014 in triode mode, and my many threads on the DAO follower.
Everyone who bothered to build my DAO follower said they have not heard better.
And I don't think, I know.
Patrick
Everyone who bothered to build my DAO follower said they have not heard better.
And I don't think, I know.
Patrick
But I can get 20pF without a cascode.
I can also simply drill and tap a hole and mount it to the main heatsink.
Yeah, but how many of them had heard a KP903A follower? 😀
se
If 20pF the only criteria than you can parallel 10x BF862 and get the same, with the benefit of ultra low noise.
If you are in for the kick-factor of using mysterous Russian military technology, that is another matter.
I am sure it will also sound wonderful. Anything JFET sounds wonderful.
Patrick
If you are in for the kick-factor of using mysterous Russian military technology, that is another matter.
I am sure it will also sound wonderful. Anything JFET sounds wonderful.
Patrick
> terrifying capacitances
Hence cascode.
> and way too low Rdson.
Why is that important in a linear amplifier ?
Transconductance, which in IMHO is what matters in linear amplification and not switching devices, is at 4S in triode mode a la Zen V9.
My own measurement, not data sheet.
Patrick
.
Hence cascode.
> and way too low Rdson.
Why is that important in a linear amplifier ?
Transconductance, which in IMHO is what matters in linear amplification and not switching devices, is at 4S in triode mode a la Zen V9.
My own measurement, not data sheet.
Patrick
.
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