All Hitachi Lateral Fet amplifier for DIY described by Paul Kemble - Page 2 - diyAudio
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Old 5th October 2012, 03:56 AM   #11
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Quote:
Originally Posted by gaborbela View Post
Hello
Thank you for your answer!
I need JFet replacement not power mosfet. Those are have at hand.
I think these is a good amplifier so it would be worth to modify the input stage..

Greetings Gabor
You could use just a pair of
2SK215 for the input .......
No cascode needed .......
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Old 5th October 2012, 05:25 AM   #12
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Quote:
Originally Posted by gaborbela View Post
Hello

I open these thread for these all Hitachi Lateral & Jfet amplifier.
The amplifier was designed by Paul Kemble (head of NAIM company)
Now for these amplifier the mosfets are still available but the JFet must be replaced because they are no longer on the market.
We started a conversation about these amp on the Naim 140 clon from Ebay thread.
We think it is time to keep that threat to Naim clone and open a new for these.
AndrewT advised to dedicate these amp to Borbely...He was famous using fets in his own high-end amplifiers etc.
Here is the website of Paul K.
A Paul Kemble web page - Hitachi Fet designs.
There is two amplifier circuit. You all welcome if you interested to comment, redesign etc these amplifier.
To the all Hitachi fet I have all the mosfets at hand just need the JFet.
I really would like to give a try (at least test these amp)but not without modifying the front end since those JFet are past now.

Greetings Gabor
Did Paul Kemble design the amp in the Hitachi databook?
http://sjostromaudio.com/pages/downl.../Miscellaneous

EDIT: It seems to be fetched from the Hitachi app note.
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Last edited by peranders; 5th October 2012 at 05:28 AM.
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Old 5th October 2012, 06:11 AM   #13
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Originally Posted by peranders View Post
Did Paul Kemble design the amp in the Hitachi databook? ....
Obviously no, but at least he redrew it in the style of his webpages schematic archive.
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Old 5th October 2012, 10:52 AM   #14
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Quote:
Originally Posted by gaborbela View Post
Hello

I open these thread for these all Hitachi Lateral & Jfet amplifier.
The amplifier was designed by Paul Kemble (head of NAIM company)
Now for these amplifier the mosfets are still available but the JFet must be replaced because they are no longer on the market.
We started a conversation about these amp on the Naim 140 clon from Ebay thread.
We think it is time to keep that threat to Naim clone and open a new for these.
AndrewT advised to dedicate these amp to Borbely...He was famous using fets in his own high-end amplifiers etc.
Here is the website of Paul K.
A Paul Kemble web page - Hitachi Fet designs.
There is two amplifier circuit. You all welcome if you interested to comment, redesign etc these amplifier.
To the all Hitachi fet I have all the mosfets at hand just need the JFet.
I really would like to give a try (at least test these amp)but not without modifying the front end since those JFet are past now.

Greetings Gabor
In that amplifier diagram, I think the designer did not understand how a J-FET transistor work. So, the operation of a JFET is not the same as a MOSFET. There are notable differences.
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Old 5th October 2012, 02:18 PM   #15
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Qua-Co is a reliable seller for 2SJ74 and 2SK170 matched pairs. He's supported the older Hafler DH- and XL- series amplifiers for many years.
HAFLER XL-280 OTHERS 2SK170 2SJ74 MATCH JFET SET OF 4 | eBay
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Old 5th October 2012, 02:36 PM   #16
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Quote:
Originally Posted by hitsware View Post
You could use just a pair of
2SK215 for the input .......
No cascode needed .......
Hello
I don't think is a good idea to replace the JFet with fet specially on the input
Even sound wise it has a huge differences between the two, like day and night.
Is a reason many Aleph X builder replaced the mosfet input to JFet and got a big sound improvement
Let s keep the JFet on the input, we can use BJT for cascode.
There are some Toshiba JFet we could probably use here with some minimal modification.
That is the reason the circuit up in here on the forum.
I do think is a well designed circuit worth to give a try specially those who like the sound of the laterals
We all know many famous amplifier was designed around the Hitachi circuit just to mention some: Goldmumd, Grand mos etc

Greetings Gabor
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Old 5th October 2012, 03:55 PM   #17
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Quote:
Originally Posted by keith721 View Post
Qua-Co is a reliable seller for 2SJ74 and 2SK170 matched pairs. He's supported the older Hafler DH- and XL- series amplifiers for many years.
HAFLER XL-280 OTHERS 2SK170 2SJ74 MATCH JFET SET OF 4 | eBay
Hello
I have those (or these) 2SK170BL&GR, 2SK246BL&GR grade and 2SK117 JFet! Can I replace the Hitachi how is the circuit? I think not..
Here I need some help, or idea. I think if we could fix up these circuit by using available devices there would be other guys who will build these amp..

Greetings
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Old 6th October 2012, 05:47 AM   #18
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Hello
Hard to believe so little interest on these amp circuit
I did look at all those Hitachi devices (good sounding fets) I thought it will be more interest....
I feel bad to give up, now when Alex already designed a layout, also I spent a couple hours drawing my layout..
Now is it time to give up??
I don't think so, I will do some test since already has all the fets (I will try to use 2SK170BL for input).
What can I do these schematic not Goldmund (yet) or other brand with $$$$$ price tag ...

Greetngs
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Old 6th October 2012, 06:14 AM   #19
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I have a DIY 100W mosfet amp based on the bipolar input version in the Hitachi datasheet. It has served as my main amp for the last 25 Years

Just because you aren't getting a lot of interest (could be fet availability, but that shouldn'y be an issue for you) doesn't mean you should abandon your project!

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Old 6th October 2012, 06:29 AM   #20
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I had a whole bunch of Hitachi application notes on audio amps using their LatFET's. I'll search them out and put up a copy on the forum. I got them around 1981.
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