• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

PP CFB toroidy OPT

and FFT 1k/10W/4R5 in REW

PP1 FFT1k 10W 4R5 REW.png
 
It's interesting that the 100Hz ripple modulation sidebands are about 20dB lower than the dominant harmonic levels.

And the IMD levels are also not (as I see it) significantly influenced by ripple sideband levels, although they show up (eg. in the 13-14kHz tones).

In either case, there is only a very low 100Hz signal showing, which is interesting, and seems to show the performance of PP output stage balancing.
 
If you are going toward the cleanest HT PS... give a try to the revised maida regulator.
i think you can find under "21st century maida".

I have used myself for a bipolar HT power supply (+/- 130V) and it performs absolutely amazingly.