What are the more subtle sounding tube preamps?

+1 for Rouge
I still have - and it still performs and sounds as beautiful as ever - a 30 something years old, Audible Illusions Modulas II. It's not in my system at this time, only because I'm currently using a integrated tub amp, but still use it on occasion, when auditioning a new power amp or rotate my ADCOM back into service. In it's 30+ years of service, I've changed out the tubs only twice and have had 0 service issues. It's  smooth, detailed and full, without adding the bloat or tubby-ness associated with some of the 80s tubes. it's overall neutral character and decent phono stage makes it a good pre. for auditioning associated power amps and players.
There are, no doubt, many finer and certainly more expensive units out there and (even though you wouldn't know to listen) is past due to have re-caped and serviced, I'm inclined to hang on to this little gem for a few more years....
Jim

I own CJ ET5 wonderful not to tubed but very musical and open sounding.I have had many tube preamps over the years such as Arc SP8,SP15,Throess etc the CJ is very accurate and not overly tubby.Good luck

ARC Ref 10.  Simply WOW!!!!

With the Cary suggestion you'll get rollable sound depending oh the 6 x6sn7s you chose.  The circuit will not defeat your efforts like an ARC will.  Atmasphere is also making a simple 6SN7 pre, He would work with you on sound.

@ebm damn man you must be exhausted after that long post! Nice job! :-p