To expound a bit on your last two questions:
1) "Will I be able to get tight bass [with a tube amp], or will there always be a trade-off here?"
Strictly in regards to 'tightness', and also to 'slam', tube amps cannot, in my experience, quite go where SS can in the bass. This is a separate question though, from which kind of bass sounds most natural musically speaking. I haven't heard the leading contenders for bass in either camp, but what I have heard I've preferred the presentation in the bass of the tube amps (as indeed I have through the rest of the range when it comes to other qualities I value more highly, such as tonality of harmonic structure and a feeling of 'liveness').
2) "I would love to have a better technical understanding of the differences between the ways SS and tubes provide headroom."
Just technically speaking, the usual description of the difference here is that SS amps clip suddenly while tube amps approach clipping progressively, and that the distortion products produced are more benign in the case of tubes. Personally, I have always been somewhat dissatisfied with these assumptions, while true as far as they go, as a good reason for explaining why it is that tube amps often 'sound more powerful' for their given output rating than do SS amps. I have found that I cannot abide listening to either kind of amp at or near clipping, so the argument that tubes clip more pleasantly doesn't cut much ice for me (it's an entirely different story when it comes to electric guitar amps, but as a player myself, I can tell you that there is not to my mind any valid parallel between the two applications). I also am not persuaded by the fact that tube amps do not clip all at once like SS amps do, since if one stays below the clipping threshold, this means that SS will remain cleaner anyhwhere below a full-on clip than will tubes - something which to me would seem to imply a greater degree of aural comfort closer to the limits with SS. There is truth to the notion, however, that a clipped tube amp will be less dangerous to the continued health of one's tweeters than will a clipped SS amp, and that it's easier with tubes to tell when the limit is being approached without going over. I have encountered some arguments as to the apparent differences in headroom quality having to do with the fact that tube amps are run at much higher voltages than are SS amps, but I lack the technical understanding to assimilate the exact reasons for this, if true. You might want to direct this question to the attention of member Sean.
1) "Will I be able to get tight bass [with a tube amp], or will there always be a trade-off here?"
Strictly in regards to 'tightness', and also to 'slam', tube amps cannot, in my experience, quite go where SS can in the bass. This is a separate question though, from which kind of bass sounds most natural musically speaking. I haven't heard the leading contenders for bass in either camp, but what I have heard I've preferred the presentation in the bass of the tube amps (as indeed I have through the rest of the range when it comes to other qualities I value more highly, such as tonality of harmonic structure and a feeling of 'liveness').
2) "I would love to have a better technical understanding of the differences between the ways SS and tubes provide headroom."
Just technically speaking, the usual description of the difference here is that SS amps clip suddenly while tube amps approach clipping progressively, and that the distortion products produced are more benign in the case of tubes. Personally, I have always been somewhat dissatisfied with these assumptions, while true as far as they go, as a good reason for explaining why it is that tube amps often 'sound more powerful' for their given output rating than do SS amps. I have found that I cannot abide listening to either kind of amp at or near clipping, so the argument that tubes clip more pleasantly doesn't cut much ice for me (it's an entirely different story when it comes to electric guitar amps, but as a player myself, I can tell you that there is not to my mind any valid parallel between the two applications). I also am not persuaded by the fact that tube amps do not clip all at once like SS amps do, since if one stays below the clipping threshold, this means that SS will remain cleaner anyhwhere below a full-on clip than will tubes - something which to me would seem to imply a greater degree of aural comfort closer to the limits with SS. There is truth to the notion, however, that a clipped tube amp will be less dangerous to the continued health of one's tweeters than will a clipped SS amp, and that it's easier with tubes to tell when the limit is being approached without going over. I have encountered some arguments as to the apparent differences in headroom quality having to do with the fact that tube amps are run at much higher voltages than are SS amps, but I lack the technical understanding to assimilate the exact reasons for this, if true. You might want to direct this question to the attention of member Sean.