Get the Amperex 6DJ8, Orange globe logo, Holland (shield, steel pins,) over the US Amperex 7308, Orange globe logo, (shield, gold pins) The 6Dj8 sounds better warmer sound and more transparent. The white lable 7803 Amperex is the best but you will pay more for those. I have rolled all of these in a Dodd preamp.
Regards
Dave