How to plot JFET?

[spoontex]

Please, anybody can help me to select a replacement for the bf245a?

witch one?

2sk30a
j113

http://jhaible.com/legacy/subtle_chorus/jh_subtle_chorus.html

Main Board:

http://jhaible.com/legacy/subtle_chorus/subtle_chorus_main_board_sch_dwg1.pdf
http://jhaible.com/legacy/subtle_chorus/subtle_chorus_main_board_sch_dwg2.pdf
http://jhaible.com/legacy/subtle_chorus/subtle_chorus_main_board_sch_dwg3a.pdf

BBD Board:

http://jhaible.com/legacy/subtle_chorus/jh_subtle_chorus_BBD_Board_sch_page1.pdf
http://jhaible.com/legacy/subtle_chorus/jh_subtle_chorus_BBD_Board_sch_page2.pdf

Thanks.

From designer old forum:

"I haven't tried a BF245C, but I specified a BF245A for a reason: The threshold voltages are vastly different."

[Clint Eastwood]

If you look up the datasheets, you can choose yourself. Look for Vgsoff similar to BF245a. Both 2SK30 and J113 should work I think. FSFX made you a kind offer, I would bite if I were you 

[spoontex]

At last I found good BF245A!

Here are the results. I need to match two of them. What would be good candidates? This 10 devices are enough? I have more of them...

[FSFX]

What would be good candidates? This 10 devices are enough? I have more of them...

It looks like devices 4, 5 and 6 are the closest matches.

BTW, not sure how you tested but you seemed to be restricting the current to less than 1mA so this has affected the accuracy of your data for higher current. As the Idss for a 2N245A is going to be between 2mA and 6.5 mA then you are artificially restricting the current so the data at the top of your graph is invalid.

[spoontex]

What would be good candidates? This 10 devices are enough? I have more of them...

It looks like devices 4, 5 and 6 are the closest matches.

BTW, not sure how you tested but you seemed to be restricting the current to less than 1mA so this has affected the accuracy of your data for higher current. As the Idss for a 2N245A is going to be between 2mA and 6.5 mA then you are artificially restricting the current so the data at the top of your graph is invalid.

with this circuit:

https://www.axtsystems.com/joomla31/index.php/projects/11-cat-1176ln-audio-compressor/4-art-1176-fet-matching