best sounding el34 tubes are in following order:
1. Philips metal base Holland mid 50's
2. Amperex bugle boy metal base Holland mid 50's
3. Mullard XF1 Blackburn fat brown base and later fat black base.
4. Mullard XF2 Blackburn double getter mid 60's
5. Mullard XF2 Blackburn single getter mid 60's and 70's
6. and the rest (Amperex, Telefunken, Siemens and winged c, Matsushita)