altering first stage 88VA

[Richard]

Hi Andy, yes the key to the pi filter for the small valve heaters is to use schottky diodes for the heater bridge which then gets you an extra volt due to their lower forward voltage loss that can be burned in the pi filter.

You won't have enough voltage for even a LDO reg, even with schottkies.

Mine's XL spec and the psu Rifas just have the polyprops and ceramic discs paralleled across their terminals. It would be possible to do it as MJ shows but it would be quite a job as things are quite tight in there as Bob says.

Yes agree with your findings of the 5751 so far! Leave it a week and then swap back is often a good plan