What's comparable to a K170 transistor?

[ben_allison]

Kind of a hard to find transistor. What would perform the same (in a preamp)?

http://pdf1.alldatasheet.com/datasheet-pdf/view/30582/TOSHIBA/K170.html

Also, any idea what the other markings indicate? BL0K? BL0J?

 

[JohnRoberts]

Those other markings may be how they are graded for Idss  BL = 6-12ma (at 0Vgs).. K and J usually stand for percent tolerance but I don't know how that applies in this case.

I used a 2sk117  Nch JFET in an old preamp design. It was a nice part and similar to that, but I can't promise it will drop in and work.

JR