There are no tube pres that I know of that have a built-in DAC. Given the design ethos of most tube-oriented companies, building in a DAC is as likely as Yasser Arafat returning from the grave and converting to Judaism. Some may offer separate tubed DACs, but to integrate them would seem to deviate from the sonic purity they strive to achieve.
I like the idea of you trying some other cable options and perhaps a good tube pre in the mix before trading the speakers. I've heard them driven by that limited edition Musical Fidelity tube gear and they were beautifully rich and warm. I've also heard them with solid state Musical Fidelity and they sounded like fingernails on a chalkboard. My sense is that they're very dependant on the signal you're feeding them, but not a weak link.
I like the idea of you trying some other cable options and perhaps a good tube pre in the mix before trading the speakers. I've heard them driven by that limited edition Musical Fidelity tube gear and they were beautifully rich and warm. I've also heard them with solid state Musical Fidelity and they sounded like fingernails on a chalkboard. My sense is that they're very dependant on the signal you're feeding them, but not a weak link.