Behold, robert casey signalled from keyed 4-1000A filament:

Been playing around in simulation with a SRPP circuit using a triode on
bottom and a pentode up top. Reason for the pentode is so I can filter
its screen supply to get better power supply ripple rejection. Otherwise
it would be a triode connected pentode. Simulations suggest that I can
get about 50dB power supply rejection with the pentode with a well
filtered screen supply. Say the triode is half a 12AU7 and pentode a
6AU6, or a 6AU6 triode connected on the bottom, and another 6AU6 up top.

Thaks Robert!

/me model addict :-)

I did the SRPP triode/pentode thing (6GH8A) and found great PSRR by tying
the screen bypass cap to ground, rather than cathode. Is that the way
you've gone?