got a bag of 30 J201 JFETs, what can I do with them?

[bikehorn]

I bought a quantity of these to build a minimal onboard guitar preamp, but at the most i'll only need 8 of them for that since each preamp only requires a single transistor...that leaves me with a bunch of unused devices. How good are these things, compared to something like a 2SK170? Can I make a decent preamp or phono stage with them? has anyone here used them for much? I looked at the specification sheet but I'm not sure what to draw from it.

[CBS240]

try matching as many of them as posible to use as pairs, and use the odd ones in the single transistor circuits. Match for Vgs. There will be a much wider distrubution for j-fets compared to BJT.

[nuvistor]

Originally posted by bikehorn
Can I make a decent preamp or phono stage with them? has anyone here used them for much?

Noise voltage for a differential pair of these is similar to the midrange JFET op amps like OPA134, fine for line level. Usable for MM phono, too noisy for MC phono, 2SK117 or 2SK170 are better choices but you can get started with these. These have been available for about 35 - 40 years and are still easy to get in the US.