best 12ax7 tube with jj el34l for Jadis Orchestra

I own a Jadis DA-60 and use 5751s preferentially . My favorite is the well known Sylvania triple mica blackplate. You might want to try some others but the rule of thumb is to use the earlier tubes with 3 mica spacers and I like the black plated tubes as do most people. That doesn't mean you have to and I think you might want to hear what a grey plate tube sounds like. The big names are Sylvania, RCA, and GE. Tung Sol and perhaps another made 5751s but were not very good or special IMO. There really aren't any true European tubes (you might come across a Siemens tube but most of the ones I have seen are relabeled GEs).
If you just want to see what one sounds like buy a current production 5751, JJ makes one and there is a Sovtek as well, or get a JAN GE or JAN Sylvania they are double mica I believe. They should be less expensive than a the 50s or early 60s triple mica tubes.
I have found the 5751 to be a very good imaging tube that should equal your Telefunken in that sense. As for extra sparkle well I don't know but you should give it a try. I did not like the RCA 7025 that I had, it was prone to distort at fairly low volumes. Good luck and listening.

I also have used 5751s in place of 12AX7s for years. The triple mica black plates from the 50s are the best. Don't buy the gray plates or the later two mica versions.

My personal preference is RCA, then Sylvania, then GE. All are excellent IMHO. GE is best bang-for-the buck.

Full disclosure: I currently have Sylvanias for sale on eBay and have a pair of GEs that I am getting ready to post.

I think that mullards have a little more sparkle than telefunkens but may not be as robust. Amperex seem to be a little softer. GE's can really brighten things up. 5751's were always to "forward" for me.