This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Here you go, the DGS#SGD pinout is standard for this package type.

VDS=-50V, 2*0.2W,gm=12 mS typ.
Idss: Y=1-3,GR=2.6-6.5,BL=6-14mA.


  • 2sk150-pins.jpg
    60.4 KB · Views: 1,920
burbeck said:
thanks James

any one succesfuly substituted 2 jfets for this dual?

matching might be the main thing to consider.
it is used on power amp input diff any advice?

2SK150 is a single chip JFET and has transconductance of ~8mS@1mA, ~12mS@2mA while maintaining low noise. Something comes close to this is two matched 2SK117 pasted together (of course, the drift would be worse). Toshiba lists 2SK389 as a substitute for 2SK150 but 2SK389 has higher transconductance so the frequency response would be different. Pasting together two matching 2SK170 is a good substitute for 2SK389 electronically (except for the drift). uPA63 or uPA68 are good substitute but I don't know where one can get them. Good luck!

Just kidding, the K150 is less than $3 each at places like Grandata if you're not in the mood to fill Mark's pockets.
Some US stores list the SK150 as low as 1 dollar 50.(some folks don't get my cynicism)

Interesting amp, never seen a schematic with a K150 on the input, only as cascode devices for higher octane dual JFETs.
It is amazing to me that still 2SK150, uPA68 can be purchased.
They were discontinued more than 20 years ago, when I picked
DIY amp as my hobby, and were difficult to find them in reputable
parts shop in Akihabara. Were those parts hiding in somewhere?? :dunno:


PS. Good luck repairing your amp, burbeck!
Mr Satoru,

apparently a lot of folks started this hobby +2 decades ago.

I manage to trace 20 year obsolete parts on a regular basis, which is not that surprising considering the sheer volume of the global distribution.
Just recently i acquired a number of metal can selected V-grade dual JFETs at a fraction of the current average commercial value.
A component i already have more than a few of, sourcing the J type complementary part in any Idss grade has been much less availing.
Astonishing is how commercial component vendors continue to succeed in sourcing rare parts in larger quantities.
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.