Agree re the Telefunkens; my favorite tubes of the 12at7 and 12ax7 variety. I would like to add a comment about the perception of spectral balance that you might find useful. Notice also the comment about the great midrange of the Tele's. I completely agree. To me the Tele's are the most refined (real like live) sounding tubes by far. But their full sounding midrange and bass in my system can sometimes create a perceived net effect of less brightness. Just food for thought. When I think "more zizzle" (but still pretty good overall) from MY stable of tubes IN MY GEAR, I think Phillips Miniwatt SQ 12at7, and Sylvania '60s vintage green label JAN 12at7, and Raytheon 12ax7 black plate.
Looking for brighter tubes
Attention tube heads: I'm looking for brighter (more treble...not higher amounts of glow and chrome) tubes, if they exist. My amp (Jolida JD502P) has a well regarded bunch of Russian Tung Sol 6550s and 12AX7/12AT7s but I'm wondering if there's anything out there that imparts more sizzle in this amp. I do like the amp as it is...but hey..."rolling rolling rolling, keep them tubeys rolling...