The Amazing Fet Circlotron by Mike Rothacher - Page 3 - diyAudio
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Old 6th October 2008, 01:50 AM   #21
The one and only
 
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Quote:
Originally posted by Charles Hansen
Anyone wanting to build one of these should do so soon. The 2SJ74 was discontinued at the start of the year. Some of the distributors will have them in stock for another year or so, but after that they will become very difficult to find.
I recall you posting that you bought about a million of them. What is your phone
number again?

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Old 6th October 2008, 01:59 AM   #22
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Quote:
Originally posted by Fuling
I recognize the circuit, Circlomanen made something VERY similar a couple of years ago
I recall that Circlomanen had a strong interest, but I can't find the schematic. Can you
post it or point us to it?

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Old 6th October 2008, 03:41 AM   #23
EUVL is offline EUVL  Europe
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> I recall that Circlomanen had a strong interest, but I can't find the schematic. Can you post it or point us to it?

Pleasure.

Supersymmetry Circlotron

And this one from me has been built with various MOSFET types & configurations. Sounds very nice and absolutely DC stable.

http://www.diyaudio.com/forums/showt...056#post931056




Patrick
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Old 6th October 2008, 10:05 AM   #24
Fuling is offline Fuling  Sweden
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Quote:
I recall that Circlomanen had a strong interest, but I can't find the schematic. Can you post it or point us to it?
Edit: Sorry, didn´t see that EUVL had already linked to the schematic.
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Old 6th October 2008, 11:44 AM   #25
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They are similar to be sure. Circlomanen is very prolific, and my hat is off to him. His name says it all.

I can promise you though, I worked this one out independently, as evidenced by my large collection of failed prototypes, and fets that made the ultimate sacrifice. The F5 provided the "lightbulb over the head."

Should there be a famine of Toshibas, if you check my blog you'll find a picture of the "Antimatter" LSK version of the boards, which will be tested right after RMAF.
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Old 6th October 2008, 01:16 PM   #26
MEH is offline MEH  United States
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Quote:
Originally posted by mrothacher
"Antimatter" LSK version of the boards, which will be tested right after RMAF. [/B]
I haven't looked for those posts yet, but would I be right in assuming that you're flipping Ps and Ns to use LSK389s for the input and something like FQA12P20s for the output? That would seem to make sense to me: Not only using a dual JFET that is (I believe) still in production, but also one that allows for significantly higher rail voltages....
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Old 6th October 2008, 01:23 PM   #27
EUVL is offline EUVL  Europe
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> I can promise you though, I worked this one out independently,

I am sure you did, and it was a very good write-up in any case.
Thank you for raising the interest in Circlotron circuits again.

I remember when I saw the first circuit from Circlomanen, I discarded it as eccentric.
Ever since I built my first a year ago, I have not been building anything else.

I think people discard the topology without understanding its many virtues.


Patrick
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Old 6th October 2008, 02:15 PM   #28
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Quote:
Originally posted by MEH


I haven't looked for those posts yet, but would I be right in assuming that you're flipping Ps and Ns to use LSK389s for the input and something like FQA12P20s for the output? That would seem to make sense to me: Not only using a dual JFET that is (I believe) still in production, but also one that allows for significantly higher rail voltages....
See my blog here: www.audiohobby.com
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Old 6th October 2008, 03:16 PM   #29
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Quote:
Originally posted by EUVL
Thank you for raising the interest in Circlotron circuits again.
Bitte schön. My Pleasure.
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Old 6th October 2008, 05:19 PM   #30
matejS is offline matejS  Slovenia
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Wow, this is really great. I love F5 (elegance, simplicity), but I like this F5/circlotron even more - since it avoids N/P matching. Anyway, is there a reason why not using F5 values, i.e. 2mV (Rs=100, Rd = 2k, Rfb= 100; instead of 10/600/50).

Thanks and congrats,
Matej
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