I am under way with a headphone amp based on 2022 FE & ACP with the hope of using up all those unmatched jfets. Please see circuit board.
My obvious question is will the 8 jfets in the mosfet constant current source deliver their Idss current reliably or might I have problems with interaction or high frequency ocilation? The 237 ohm resistors are there primarily so I can gauge the current from each jfet but my thoughts are they may help stability too.
Secondly, I note the ACP is optimised for 32 ohm load but I have Focal Mg headphones at 55 ohms. So how would I optimise the operating point Of the output mosfet for this load.
Finally, I intend using 6 jfets in the Long Tailed Pair rather than the usual 4 so what bias current range would be appropriate for the LTP as I need to specify P1 based on this.
Any comments would be most welcome.