All Hitachi Lateral Fet amplifier for DIY described by Paul Kemble

[gaborbela]

Hello

I open these thread for these all Hitachi Lateral & Jfet amplifier.
Here is the circuit & website.
A Paul Kemble web page - Hitachi Fet designs.
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.
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

[jackinnj]

Very similar circuit was in The Audio Amateur over 20 years ago by Erno. The MOSFETs in the middle are unobtanium, although you sometimes see them on EBay.

[gaborbela]

Originally Posted by jackinnj

Very similar circuit was in The Audio Amateur over 20 years ago by Erno. The MOSFETs in the middle are unobtanium, although you sometimes see them on EBay.

Hello
Those mosfets I have that would be no problem at least to me.
The J fet is the problem. I did tried to look up the mentioned circuit maybe Mr. Borbely did used Toshiba or some other type (still available JFet) but with out success.
I do like these circuit a lot (all do I would be more interested how it sound)
A great circuit not always equal with a great sound

I started to draw the layout but I stopped because I don't know what JFet I could use to replace those old Hitachi, or what kind of modification I need so I can use Toshiba JFet..
Greetings Gabor

[jackinnj]

There are some 2SJ77 available at MCM Electronics.

[hitsware]

Originally Posted by jackinnj

There are some 2SJ77 available at MCM Electronics.

Hitachi 15V .5A 30W Gds Hitachi Fet TO-220Ab N-Ch | 2SK215 | Hitachi
200V .5A 30W Gsd Hitachi Fet TO-220Ab | HITACHI *SS | Distributed By MCM
160V 5Ma 30W Gsd Hitachi Fet TO-220Ab P-Channel | HITACHI *SS | Distributed By MCM

[gaborbela]

Hello
Thanks, good to know those still available the 2SJ77/2SK124, in case someone else interested on the amp.
I have at home 8 pair right now, also I have a lot of different type power mosfet from Hitachi, Class D, EXICON..
The issue here the JFet, unfortunately those are not available and if I will get the still problem because those must be matched.
There are companies who sell obsolete (hard to find)devices but min order $500 or they sell them for horrible price.

Greetings Gabor

[alex mm]

....nice stuff , and now, you have PCB as well if you like this layout ......
as usual my contribution .
Regards Alex.

[gaborbela]

Thank you (multumesc) Alex!

Nice PC bard layout. Only question remain if any Toshiba JFet like 2SK170, 2SK246, 2SK117, or 2SK30A can replace the Hitachi Jfet with out major modification.
I have at home all of these devises.

Greetings Gabor

[lanchile]

you can use 2SK1058 and 2SJ162 from Renesas.

[gaborbela]

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