Better 6922 for the preamp, but remember that the manufacturer designed your unit with modern sounding tubes in mind so you want something better in that direction meaning linear sounding tubes.
Believing that your pre has Sovteks or EH I would go with Siemens Halske E88CC and Cca up to 1967 production, for a classic tube tone, or their bigger brother E188CC same period, for more bass and treble. But definitely i would try to find some Voskhods 6N23p 74-79 production for their better flow and the info retrieval at a much lower cost.
Of course you can try anything from that family and you can get better results from the ones you already have as long your pre does not push them too much in which case your choices are limited.
A good move is the check with BAT if that is the case before spending your cash.
For the power amp I would check to put the best I could afford in the cathode follower position leaving everything else as is.
A new world.
Believing that your pre has Sovteks or EH I would go with Siemens Halske E88CC and Cca up to 1967 production, for a classic tube tone, or their bigger brother E188CC same period, for more bass and treble. But definitely i would try to find some Voskhods 6N23p 74-79 production for their better flow and the info retrieval at a much lower cost.
Of course you can try anything from that family and you can get better results from the ones you already have as long your pre does not push them too much in which case your choices are limited.
A good move is the check with BAT if that is the case before spending your cash.
For the power amp I would check to put the best I could afford in the cathode follower position leaving everything else as is.
A new world.