OP's question is very good question, and it should go with any speakers. Don't limit the range of speakers when we reply the questions.
Here is my answer if you want to have a good setup.
1, tube power amplifier
2, tube crossover in the speakers.
3,tube preamp
Choice 3 is optional, you might get SS preamp instead.
Here is the point with the speakers: some speakers has separated crossover and could replace easily and if the crossover is inside the speakers, it is very different to replace.
The crossover has very strong point to the sound which can compare with preamplifier ,but in long time, we ignore it.look back the vintage UK speakers, they always have outside crossover which let us to modify easily later.