look in the art of electronics for the simple power amp circuit fragment
Vr should be higher than 1/2 Vcc
First there is a 3 or more volt G to S difference needed to turn most MOSFETs on
Next you can "pull" harder to the B+ with the Mosfet (RDSon) than the resistor can pull to ground.
Think current, advailabe each way from the Q point.
You high end might have a drop because of the MOSFET gate cap (forms a RC lowpass) with the 2.2K and output Z of the jfet driver.
You might be better with a 100K linear pot and a input gate to ground R for a more true log curve. Look at geofex.
How much current do you need source and sink for what Z headphones?
Vr should be higher than 1/2 Vcc
First there is a 3 or more volt G to S difference needed to turn most MOSFETs on
Next you can "pull" harder to the B+ with the Mosfet (RDSon) than the resistor can pull to ground.
Think current, advailabe each way from the Q point.
You high end might have a drop because of the MOSFET gate cap (forms a RC lowpass) with the 2.2K and output Z of the jfet driver.
You might be better with a 100K linear pot and a input gate to ground R for a more true log curve. Look at geofex.
How much current do you need source and sink for what Z headphones?