The search AC engine is your friend! Then reinforce with Google.
Jim's Butcher's Bill calls out the Sovtek 5Y3GT (unlike a "real" 5Y3GT, the Sovtek is indirectly heated, hence a slower power ramp)
(I like the sonics and the slow power ramp from these)
Others have used:
Mullard 5AR4 Metal base,
Mullard 5AR4 Fat base,
Mullard other 5AR4,
RCA-Sylvania-Raytheon-Mazda, etc. 5Y3GT's,
Plus many more variations have been tried. The voltage drops differ, so always check the spec sheets. The B+ voltage, measured after R221, should be 330v. You may need to tweak the values of R220 and R221 to achieve 330v with any other rectifier than Jim's spec.