Design Help needed with IRF820 source follower

[mooreamps]

Oh I see. I think that's what I put the 12V zener in for. Was there something else that should be in there? I was hoping just to use 1 x IRF820 as a source follower in conjunction with the LFO triode in the BFPR circuit, as per the way I had done the schematic (now attached duh! - sorry), borrowing from the 5G9 values where it has a CF in the same position, and accepting a 12V zener from the gate to the source and 100R in series with the gate.

I took a brief look at this schematic. this is a nice job. I hope it works out for you.


-g

[Steve Conner]

Pretty much all MOSFETs are enhancement mode, except that LND-thingy and a few others. So you need different bias schemes for them.

The exception being the direct-coupled CF, where it doesn't matter, you can substitute either an enhancement or depletion mode FET directly for a tube.