Have to admit I'm a little shocked here if I have this right. You run the PS DAC directly into your amps right? Then you insert an $11,000 very highly-regarded tubed preamp and you basically hear no difference? I'm sure you heard what you heard and I know every system is different, but damn I'm really scratching my head over this one.
That aside, some speakers I've heard that are detailed but maybe a bit less analytical sounding than the S5s are Rockport, Nola, Verity, ProAc, Vandersteen, Joseph Audio, Sonus Faber, Martin Logan. Also, you may want to explore speakers that employ the Raal ribbon tweeter -- the speakers I've heard with it are very detailed but incredibly refined and sweet sounding, which may appeal to your tastes. Anyway, just some thoughts to possibly explore FWIW, and best of luck in your search.