Tube for aesthetix pandora / romulus


Hello,

I own an aesthetix pandora dac and i am thinking of upgrading its tubes:
- 2 E83CCS or 12AX7
- 2 6922 (6DJ8)

I have been advised to get mullard, siemens or telefunken nos valves

I don't know anything about tubes...

Would you have recommendation? Advises? Tips? Good tubes sellers?

Thanks and regards
G.
guiche
I tried Amperex ECC83 Holland tubes from the 50's (Haarleen plant) and did not like them in the Aesthetix. I don't see how phillips would be better.
Dont knock em till you try them. Phillips Delta codes 1960 and up to about 69.
BTW, I dont really like high gain ECC83 in Dacs, but hey...much prefer 81s and 82s.