3020 FET -any replacement?

[clinic-audio]

Hum .....

Not really simple

2SK100 is not usable for 2SK99A (or B) !
2SK99A and B data :
VGSS -25v
IG 10mA
PD 100mW x2
IDSS 1,5 mA to 20 mA
gm 80 mOhm min (VDS=10V f =1kHz) that's a problem usually such double FET in same package give a MIN of 15mOHM not 80 ...

will make some research (takes time) and come back with report

 

[jfazende]

I take a look and come back to you as soon as possible

User FootFungus posted: "It looks like a matched pair of 2SK170 or LSK170 is probably the way to go from searching around AK."
Do you believe that to be the case clinic-audio?

 

[clinic-audio]

Transconductance Differences (linear Systems)

A key parameter for JFETs is transconductance at a given drain current.
This number varies little over IDSS and threshold voltage in a given process, but it is generally different for P-channel and N-channel devices.
Transconductance of a JFET increases as the square root of drain current.
While the gm of the LSJ689 is about 3000µS at 1mA, that of the LSK489 is about 2500µS at 1mA

You are talking about 2SK170 but which one ?
If you wish to use those you have to match them closely . It may work but not the way it should

 

[jfazende]

Transconductance Differences (linear Systems)

A key parameter for JFETs is transconductance at a given drain current.
This number varies little over IDSS and threshold voltage in a given process, but it is generally different for P-channel and N-channel devices.
Transconductance of a JFET increases as the square root of drain current.
While the gm of the LSJ689 is about 3000µS at 1mA, that of the LSK489 is about 2500µS at 1mA

You are talking about 2SK170 but which one ?
If you wish to use those you have to match them closely . It may work but not the way it should

Linear Systems sells 2SK170 equivalents, they are matched pairs: LSK170, Grades A, B,C,D.
I think I need grade A, see link for product: https://diyaudiostore.com/collections/parts/products/linear-systems-lsk170?variant=5927699460

Do you agree?

 

[jfazende]

Linear Systems sells 2SK170 equivalents, they are matched pairs: LSK170, Grades A, B,C,D.
I think I need grade A, see link for product: https://diyaudiostore.com/collections/parts/products/linear-systems-lsk170?variant=5927699460

Do you agree?

Just noticed LSK170 Vgss -40 minimum. May not work.

 

[clinic-audio]

LSK170 Grade C is same as 2SK99A
Grade A is not enough
Just noticed LSK170 Vgss -40 minimum. May not work. 2SK99A VGSS is -25V

 

[jfazende]

LSK170 Grade C is same as 2SK99A
Grade A is not enough
Just noticed LSK170 Vgss -40 minimum. May not work. 2SK99A VGSS is -25V

Thank You!

 

[jfazende]

clinic-audio - LSK170 Grade C is not available, but Grade B is available.
Will Grade B work to replace 2SK99A?

 

[jfazende]

LSK170 Grade C is same as 2SK99A
Grade A is not enough
Just noticed LSK170 Vgss -40 minimum. May not work. 2SK99A VGSS is -25V

clinic-audio - LSK170 Grade C is not available, but Grade B is available.
Will Grade B work to replace 2SK99A?