Tube Upgrades for CJ MV-52?

1st, The MV-52 was essentially a modded("improved") version of the MV-50.
2nd, The MV-52 used 6FQ7's, not 6SN7's
Based on My Experience With the MV-55 for some time, here are my choices in order of preference.
El-34's
1. Mullard Xf2 double getter
2. Svetlana (current production)
3. GE USA (Big Bulb)
4.Electro Harmonix
5.Tesla EL-34S

12ax7/5751
1. Telefunken
2. Amperex Bugle Boy
3. Tungsol
4. Sylvania (blk Plate) 3 mica 5751

Again, these are personal opinion's based on My Tastes,system,and amp.
Cheers,
Shred