Here's the power supply I've lashed up to feed the balanced SE classA amp.
Its fed from a 5VA EI transformer with a 65VAC secondary. One 390uF cap follows the rectifier, then there's a 30mH choke, two 390uF caps beyond that.
A series regulator is made from a string of 3 TL431s as reference (the max from a single one is 36V - I've gone for a total of 78V) and that's followed by a 2SK213 simply because I had no other high voltage transistor to hand. There's an RC filter feeding the gate of the MOSFET to reduce the output noise from the shunts (68k,200nF).
Output ripple isn't visible on my scope but I plan to feed the output into my AC millivoltmeter and see what its giving out in terms of noise.