There are so many NOS or UOS 12au7s available you may want to try a few.
also the industrial versions and military versions of this tube are quite good such as the 5814 and 6189.
You may want to buy a few and see what you like.
Seeking a recommendation for 12Au7 tubes for Conrad Johnson ET6SE preamplifier
Looking to purchase the Conrad Johnson ET6SE preamplifier new from a dealer. I was advised that this preamp comes from the factory with 4 12AU7 tubes by JJ Electronics. In short, I am not saying anything negative about the JJ tubes, I just believe the sound they deliver can be improved upon. Would appreciate any suggested tubes for this preamp. Thank you.