combination tube amp and ss preamp?

The problem with mixing a ss pre and tubed amp is input/output impedance... if you find a ratio that works, it is fine... next, over all a tubed amp add much more of the "tube experience" than a tubed pre. If you are after more of the warm tube experience, you would most likely enjoy this combination.

Problem with a tube amp, for a retired HS teacher anyway, is over time you spend more money on tubes than the amp cost.

B&W Diamond speakers have a warm sound already. You probably don't need to enhance the warmness with a tube amp.

Big B&W speakers prefer large high current solid state amp to control the bass and put it in order.

This is just a general understanding but individual taste does dictate choices.

Problem with a tube amp, for a retired HS teacher anyway, is over time you spend more money on tubes than the amp cost.

That might take a few years or decades depending on the amp.

The best thing about a tube amp is that you get to buy all sorts of interesting tubes for it over the years which results in you becoming a partner in its performance, you seem smarter and better looking, and are happy forever no matter what. These are facts...if you buy tubes for a solid state amp they just sit there and get all dusty and sad...to sum up: Be happy forever or dusty and sad. It's your choice.