Okay, cap can be anything reasonable, the old 40MHz Schlumberger CRO should be able to see the ripple down to there, I think - it's not really up to seeing the "glitches" in the diode transfer function but still quite usable.
I also added an isolation transformer ( an old industrial one that allows the split secondary +/- 120V ac out here (balanced primary supply lines, or something like that!) to clean up the power - just generally quieter and nothing really dramatic - expected more - bloody great 2kVA EI lump of metal in an old brown ugly case!
I haven't used any "R+C, in // C" on the secondaries - must try this out - Hagermans, yes? I usually stuff around with tuning the damn secondary windings - a right real PIA that takes a lot of time and patience.
I was going to try those MSR diodes, the super quiet ones (MSR1520, or similar?) and something similar to your diode snubbers (4.7uF + 0R47).
I see you didn't need to use the C-R-C but just straight into the Kmx - that certainly makes it simpler - will play it myself -
I remember 'juma' saying the simpler single cap gave superior performance than the C-R-C, with his simple Cmx for his smaller triple fets F5 version - another variation to try out.
Is that extra transistor to increase the base drive on the Q2 o/p transistor, and the C1, R5 for extra stability? Increased bias to 5 volts? 56 volt rails, a big power unit?
Interesting things, these Cmultipliers - don't know why they've become "unfashionable" these days and it's hard to find people that have ever added a resistor to a cap and hung it across the diodes - never could figure out why it's not taken off as it's so simple to try.
It's a bit the same with trying to get people to knock up a simple Schroeder defuser and lean them against the wall in the room - people look at you funny when mention these things (or more than usual, anyway!)
Yes, I 'recon' a half way decent power supply is "money for nothing" in audio terms, and a good one .....