I need advice on a problem I'm having
I need a follower to transmit an AC signal into a low impedance load which is the cathode of a triode but I also need it to be an adjustable current source to the load.
Unfortunately normal current sources have gain, I need a unity gain current source so the AC signal is not amplified.
The ac signal voltage is about 20v and the DC voltage levels are from 0 to -300v and I have access to 300v apex opamps if needed but I'm a novice at circuit design so I'm not sure how I would design it.
Edit: Sorry I think people are getting confused.
Ignore the opamp.
The 1uf capacitor carries the audio signal.
The cathode presents an ultra low impedance so I need the source follower for a buffer.
I want the audio signal to pass through the follower untouched but I also want the follower to provide a constant current to the load.
Imagine the 150k resistor as the current source bias. The problem is figuring out how to replace that fixed resistor with a variable current source bias.