jfet question 2n4093

[clockman]

An electrician/ ham radio enthusiast friend gave me these. A truly kind and generous gent. I did some research,  substitutions list 2n4857 and 2n4392. anybody ever work with these? I've yet to build a Jfet tester/matcher but may be inspired if anyone could suggest a circuit that calls for any of these numbers.
 thanx for your time, Tom.

[Frank_NH]

Here's the datasheet:

http://www.mouser.com/catalog/specsheets/InterFET_DS_2N4091_3.pdf

Idss is rated at a minimum of 5 mA and Vgs(off) = -1 to -5 volts.  This puts it in the same range as the MPF102 JFET, and so could probably substitute for that specific transistor in effects circuits.

As a side note, I just finished a Dr. Boogey and used J230 JFETs instead of J201s.  Their Idss, Vgs(off) lie between J201s and 2N5457s, so the gain is slightly lower than J201s.  They worked just fine, and biased with no problem (though I used 50K trimmers versus 100K, which are much too large, even for the J201s).  The point is to go ahead and experiment with different JFETs given that the J201s and similar are becoming more difficult to get.

[clockman]

thanx for the quick reply.
 I haven't tried many JFET circuits yet. I got a hesitant reading the many posts of woes and tribulations, so I only picked up a few 2n5457s for a couple of things. definitely want to try more though and so many cool pedals out there... the research continues! thanx again