need alternative transistors and need a little help

i'm looking for better transistors to try out on this old JBL mic pre.
they are jfets and i have no idea on how to find replacement transistors. i'm thinking these transistors were made a long time ago and i'm thinking that there may be better made transistors to fit this application. i'm just looking to get more gain.
here is the schematic:

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5600-2Bmanual.pdf

The "82456" in the schematic is probably an internal JBL part no.

I don't see why you shouldn't be able to use something common like the BF245 or the like..?

Jakob E.

Looking at the last page look at the source leg what connection can you move to get a little more gain? Thats what I would try first

If you decide to change the fets be mindful of the drain to gate voltage and issues it can cause. 34 and 19 google Pease-Cohen Effect

BF245 might have an issue with the Vdg IIRC it is a NS P50 process type fet.

I would do a bit of reading on FETs before I changed them. Some good stuff can be found with google and looking at manufactures sites.

hints IDSS Vdg