Hi Phaelon, take a look at my Gon review on the Mazda 12AU7 for details why you might love this tube in the context of your system.
Which Telefunken 12ax7
I'd like to hear from members who are familiar with NOS Telefunken 12ax7s from the 1950&60s. I've spoken with three different tube vendors who are frequently recommended on this forum and received three different assessments of the ribbed vs smooth plate versions. One vendor said there was no sonic difference, while the other two were opposed as to which was warmer and which was more detailed. I sure would appreciate it if you guys could help straighten this out.