Another point to consider is that we are talking about line stages or preamps made after the 90’s and manufacturers did create their preamps with one russian type tube in mind for both durability and sound. The Russian NOS variant 6n23p/6n23p-v/6n23p-ev can last long and play great. Especially the 6n23p Voskhods, 1975-1979 period and the ultimate 6n23p Reflektor 1974-1975 period. These 6n23p (and even some made in early 80’s) would be the best version of that voicing compared to any tube made in the 50’s-60’s.
These particular 6n23p can smoke everything in 6922 family, can take punishment but unfortunately in the last years their prices have gone crazy, and if you can find the proper ones they easily surpass the western alternatives.
The EV versions- different tube not in the same league as the above but reasonably plentiful, and they were destined for space travel too.
