I am not sure I can add much more to the above posts (particularly jmcgrogan's), except that I've owned both the BAT Vk-5i and the Thor TA-2000. To give you an idea of my sonic biases, I preferred the Thor over the VK-5i in all categories (e.g., tonality - which was more natural and extended, particularly in the upper midrange to treble- imaging, micro and macroynamics) save one: the Thor was just a touch noisier than the BAT VK-5i. In my system, I also found the Thor was a little more versatile when used with other amplifiers (including everything from an Aragon 4004 Mk II to Conrad Johnson Premier 8XS's to CAT JL-1's), whereas the BAT performed at its best for me only when paired with BAT amps in a balnced configuration. However, either one could be used with a solid state amp, particularly given the matchings that you propose. I never had any problems with either preamp, and found their respective companies to be both very accessible and willing to answer questions.
As to BAT's and CJ's top of the line units, while I demoed the VK-50se (one of BAT's previous top of the line), I was not sufficiently enamored of its sound to pursue further investigaion, and felt that the cost difference in upgrading from the VK-5 to the VK-50 was not justified. Moreover, given your stated preferences, I think the VK-5i more closely matches your desire for a euphonic-romantic presentation than the VK-50, which was more neutral and detailed than the VK-5i. (However, these opinions are based on one extended listening session with the VK-50se, so take that opinion with a large grain of salt).
The CJ ART/ACT preamps, on the other hand, are among the finest, if not the finest, active line stages I have heard. They provide everything you are looking for - sweet, balanced, a touch romantic, with natural sounding mids and authoritative bass, - but still are outstanding at resolving low level information, and present an extended, airy, and grain free treble. Thus, I would urge that you give tham a listen, if possible. (I would also suggest you skip the CJ 16LS, and go straight for the top of the line CJ units.)
As to BAT's and CJ's top of the line units, while I demoed the VK-50se (one of BAT's previous top of the line), I was not sufficiently enamored of its sound to pursue further investigaion, and felt that the cost difference in upgrading from the VK-5 to the VK-50 was not justified. Moreover, given your stated preferences, I think the VK-5i more closely matches your desire for a euphonic-romantic presentation than the VK-50, which was more neutral and detailed than the VK-5i. (However, these opinions are based on one extended listening session with the VK-50se, so take that opinion with a large grain of salt).
The CJ ART/ACT preamps, on the other hand, are among the finest, if not the finest, active line stages I have heard. They provide everything you are looking for - sweet, balanced, a touch romantic, with natural sounding mids and authoritative bass, - but still are outstanding at resolving low level information, and present an extended, airy, and grain free treble. Thus, I would urge that you give tham a listen, if possible. (I would also suggest you skip the CJ 16LS, and go straight for the top of the line CJ units.)