Help biasing jfets

[motterpaul]

Usually jfets are biased at half of the circuit voltage. This looks like a 9v circuit to me, so I would bias each jfet for 4.5v.

If you can see voltage as high as 18v, I don't know how you are doing it. I don't see a charge pump (an IC that acts like voltage doubler).

[dexxyy]

you want to bias the drain to roughly half the supply voltage. if supply is 9v bias drain to 4.5v, 12v-6v, 18v-9v etc. once that`s done I usually fine tune by ear.

[MaheshSK]

Thanks for the reply ill be using a 18 volt adapter to get my supply ny ways this is gonna be my preamp section of a practice amp. So 18v is already there..

[motterpaul]

I do almost all of mine by ear these days.

[MaheshSK]

Hey guys. I gave 12 volts supply and its the same result biased q1 n q2 to 6volts and q3 to 7volts. Is there any ways to check if the jfets are good?