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.
Question was answered by a kind member in an email.
minimial....as i guessed.....carry on fellow Agonners...
The better 12AX7A you can get in the world for your Jadis it's the SIEMENS E83CC (European name)... I have my DPL and my DA-8 fully tubed with SIEMENS!!... It's another league respect to the actual tubes...
I really love the Psvane Premium grade 12AX7 even over the Siemens NOS that were mentioned earlier at a cost of around 75.00 matched pair. 
I had bad luck with the Psvane 12AX7TII tubes…sloppy manufacturing (bad labeling overspray) and a fail…after trying NOS Phillips (another fail…weirdly) and various other recommended brands (the overflow of 12Ax7s wind generally up in one of my guitar amps) I went with new Russian (there are "official" Chinese GL versions I haven't tried) Gold Lion matched and balanced 12AX7s and they sound great. Bought 'em from "thetubestore" who honored the warranty on the Phillips. I like those guys.
Tesla E83CC frame grid, box plate tubes are very nice. Beware of fakes, but JAC music website has useful info on spotting them.