Koda, thanks for the tip on the small chokes, I've just ordered two. I've been to A-1 a couple of years ago. Got a few Hammond trannies on order from A-1.
No wonder I was getting hum, that 2 volts was going straight to the control grids of the OP tubes. Added caps after the R and it's much better but not perfect, a work in progress.
It never occurred until now that you need a really clean bias supply. Always learning.