I have currently used the following :
- Ken-rad VT231 Black Glass, Staggered plates (1940s)
- PSVANE CV-181 Tii (New production)
- Linlai E-6SN7 (New production)
- Sylvania 6SN7 Bottom D foil getter with Flat black plate
- Raytheon 6SN7GTB
- Stock tungsols
I currently am planning on looking for the "original" MELZ 1578, but as of now I find the ken-rad to be the best I got. Also as suggested by someone in the thread, I have read that supposedly the mullard cv181s is top tier, but for the price it commands, I think it might be better to consider 300b rolling earlier
. Raytheon VT-231s are supposedly good as well, on my shortlist.