Not sure, never used JJ EL34 power tubes in any Mesa amp. The exception was the 6CA7, they did not last very long, I was lucky to get 2 weeks out of them before one stopped working and ended up with taking out screen resistors. Was not a good experience but the tubes did sound good while it lasted. Mark V90 was the amp in question.
As for the EL34 JJ tubes, I only see the EL34L suggested for the TC50, it may be due to its lack of low end compared to the TC100. If Eurotubes is recommending the EL34II that by be the better choice. The description of the EL34L looks more appealing than the EL34II. Just read about the power tubes. The BAD can use a bit more "in your face aggression" in the EL34 tube department. So far I have only use the STR447 (EH EL34 tube) for many years. the STR446 is new (TAD red base EL34) which seems promising and sounds great. If the JJ EL34 tubes had merit, I would think that Mesa would have some in their tube offering. At the moment, they do not (excluding the fact the STR445 is the JJ 6L6GC tube).
As for the EL34 JJ tubes, I only see the EL34L suggested for the TC50, it may be due to its lack of low end compared to the TC100. If Eurotubes is recommending the EL34II that by be the better choice. The description of the EL34L looks more appealing than the EL34II. Just read about the power tubes. The BAD can use a bit more "in your face aggression" in the EL34 tube department. So far I have only use the STR447 (EH EL34 tube) for many years. the STR446 is new (TAD red base EL34) which seems promising and sounds great. If the JJ EL34 tubes had merit, I would think that Mesa would have some in their tube offering. At the moment, they do not (excluding the fact the STR445 is the JJ 6L6GC tube).