PY 81 as power rectifiers?

[Terry]

Is there a reason its not a good idea to rectify the ground side of the mains transformer.
Anode to chassis, cathode to transformer secondary, other end of secondary to smoothing for HT+
( I have some transformers that would suit this idea nicely)

Nothing intrinsically wrong with the idea but why would you want to do it? And what is so special about your transformers which particularly makes them suitable for this application?

As for the PY81 suggestion, the live top cap(s) could present a danger risk - particularly as your 'glow' comment suggests that you aren't intending to hide them away safely!