On the previous post I explored how more power could be extracted from the 45 in class A2. Here is a first draft circuit using the 4P1L as the driver stage with a mu-follower gyrator load to provide current with low output impedance:
3.5W can be obtained with 13Vpp input signal. Clearly a pre-amp is required, but that is the output level I’m currently getting from my preamp so should be fine. The LND150 CCS reference can be optimised and derived from the stable 280V.
Not a bad idea, just an additional power supply to avoid any nasty cap in the path.