So, right, " I think I may have reached my keeper".
It is: the Sophia Electric 91-01 300B Monoblocks;- with:
tubes:
Princess 300B
Sophia 6SN7
Shuguang 5Z3PA.
Attachment 20360
Had to get a balanced step down transformer coz it has US voltage (120v);-
https://airlinktransformers.com/prod...supply-bps0508