Hello everybody! 
As I am a new member I hope this section is right for my topic and I quickly introduce myself: I am a 40-y.o. guy 😎 from Italy and work on Automation Engineering.
The topic is: I am searching for information about Toshiba 2SK389-GK dual JFET. On Internet I only find datasheets which contain codes -GR , -BL , -V , but nothing about -GK. They have different IDSS values and ID-VDS curves.
Most of all I am searching for one piece of 2SK389-GK.
Thanks in advance!
PS: image of the JFET attached
As I am a new member I hope this section is right for my topic and I quickly introduce myself: I am a 40-y.o. guy 😎 from Italy and work on Automation Engineering.
The topic is: I am searching for information about Toshiba 2SK389-GK dual JFET. On Internet I only find datasheets which contain codes -GR , -BL , -V , but nothing about -GK. They have different IDSS values and ID-VDS curves.
Most of all I am searching for one piece of 2SK389-GK.
Thanks in advance!
PS: image of the JFET attached
Attachments
I don't know where this pic came from. The original Toshiba datasheet on this obsolete dual Jfet only shows 3 different Idss grades were made.
GR = 2.6 to 6.5mA
BL = 6 to 12 mA
V = 10 to 20mA
The BL grade was the most common and the 2SJ109 is the complement.
There are many fake and counterfeit devices around of these and maybe the one in your picture is one of those wrongly marked. Good luck.
GR = 2.6 to 6.5mA
BL = 6 to 12 mA
V = 10 to 20mA
The BL grade was the most common and the 2SJ109 is the complement.
There are many fake and counterfeit devices around of these and maybe the one in your picture is one of those wrongly marked. Good luck.
Thank you, Gary.
It is a genuine Technics SU-A900 MK2 amplifier, never repaired. I don't think the JFET I took the photo of is a fake. I suppose it is a less known release.
From my test, ID=1mA @VGS=-0.2V @VDS=10.7 V , but such values don't match any curve by Toshiba (I think on the same datasheet you got the values you wrote).
Hi Samuel, I think the "dual" assembly guarantees the same temperature on both units (working in differential mode). Does a pair of matched LSK170 work the same way? How?
Thank you.
You thermocouple them face to face (better, but the pinout is different) or side by side, one rotated 180°, thermally coupled back & face to face and back (worse, but the pinout fits 2SK389).
Maybe way back when these were made, Technics was able to purchase a special batch with a tighter Idss range that was not in the commercial range.
if you really want to replace them, why not buy a pair (Bl or V) and replace the two instead. in my opinion that was GR or special gr grade .
I thought about, but -BL , -V , etc. have different curves. I got the polarization point from the other channel (which is in working order) at VGS= -216mV , VDS=10.57V , IDS=1mA. It doesn't match any of the curses about 2SK389xx / LSK389x devices by Toshiba nor by Linear Integrated Systems.