Jadis Orch pretubes 12AX7A, upgrade advice...

Know absoluetly nothing about tubes. Would changing out the 2 little pre tubes on my Jadis Orch Reference make a slight change in sound...for the better of course. Need more dynamic's in the highs, if I can get a slight increase, I'd be happy to spend $100 on a pr. I guess everyone is going to have their favorites, so may have to buy 2 prs from the best pics, compare the 2, and sell off the other pr.
Does not give a name on the Jadis tube, just says 12AX7A.