Tubes for Jolida Fusion Preamp

I have a Jolida Fusion pre which takes 2 12AX7 and 2 12AT7 tubes. Looking to upgrade from stock tubes and request herein recommendations. Thanks.
Check out Vintage Tube Services. Andy can provide some excellent recommendations. Great service. Reasonably priced.
I have the fusion DAC pre and run GE black plate triple micas and it sounds excellent. Contact tctubes in st paul, mn. They are a husband and wife business and I cannot recommend them enough. Best of luck.
I owned that preamp and it was fun to roll tubes in it.
First decide what type of timbre you are looking for in your system. NOS tubes will sound better than new production tubes, but they are priced higher according to availability.

RCA Blackplates have a very open classic tube sound. I also liked Amperex (Holland) which produce an extremely wide and deep 3D image; however, they will reveal the flaws in a poorly mastered CD.

TCTUBES is a great company, but also check out the Brent Jessee website. It has lots of info on tube types and their particular sonic signatures; plus he has a large inventory of tubes.