If you had to choose: tube amp or tube pre-amp?

As to which type of amplifier SS or tube will sound more dynamic is completely dependent on the speaker they`re matched with (this can`t be emphasized enough).Same is true for bass performance.Based on the designer`s intent some speakers need more or less damping factor from the power amplifier(output impedance level,yes or no NFB levels), also depends on the speaker`s Q factor.Generalizations don`t hold up, you must account for the numerous parameters involved.
Regards,

I used to be in the preamp camp first until I got my Eico HF20 rebuilds from JWN - get a really good tube amp first and then match that with the best tube pre you can find

Having read hundreds of posts on the sound of tubes, I’m not sure there is enough agreement on what that sound is to use the term as a descriptive device. But that said, and in general, tubes can have an influence over a host of elements that collectively make sound musical. IMO, different tube component types e.g., amps and preamps, tend to impact different musical elements with lesser or greater weight. So, depending on one’s priorities, there is no definitive answer as to which is preferable - tube amp or preamp. Personally, I require output power tubes to achieve the results I want.

To me it depends on the size of your room and the music. In my uncle's rectangular listening room which is quite large (sorry I don't remember the dimensions) he paired a pair of Threshold monoblocks with an tube Audio Research preamp. Heavenly sound with any kind of music. For me in a nearfield set-up where I was about 6-7 ft away I was able to use a solid state Accuphase C200 preamp with a Baldwin tube amp that had a power tube complement of 6L6GB/6V6GT tubes that sounded pretty awesome.

If you worry about the financial cost of re-tubing an amp (although perhaps only equaling the annual cost of leaving your SS gear ON ALL THE TIME), you need to factor in the MENTAL cost also...thousands of suggestions and opinions about re-issues from Russian factory workers on the Volga and Chinese fancy presentation boxed electron beam bottles, antique esoterica harvested from rusty Swedish radios and Cold War East German helicopters...it's insane, but worth it if you can take it. Get clearance from your therapist, and be prepared to lose all your friends...*sigh*...