he would have, IMO, served better to do short riffs & run through, then do the 2nd & cycle through. by the time you got to 21, you have no reference of a tube, more than the last tube... A couple that stuck out, although, I don't remember what they were, in the middle. The Telefunken #2 stuck out as smoother w/ a warm midrange. There were a couple more, in the middle, but, I'd have to go back & find them. The rest were mostly similar. There was one, that was an ANOS tube, in the middle, that, IMO, sounded hollow & nasally...
It's always a matter who good they still are. I'm still waiting for a more scientific and systematic approach on this in combination with a good player Good data on tubes is the very least to get me truely interested. But he made a good effort, he tested an RFT and also a long plate Philips (Bugle boy). What's interesting is that all my RFTs have a Mu of at least 102 on both triodes, while the long plate philips ('54-'59), have a Mu of around 90-95 (but a lot of variation in between, I have 20+ of those), Blackburn short plates around 92-97, Heerlen (Philips) also 90-95.
The only way to accurately or completely test them is to actually test them on a good mutual conductance tester. You need technical data for proper comparison along with actual use. A good current production Sovtek will test and sound better than a vintage crappy testing Mullard.
I would gladly borrow my finest tubes to someone who can compare them the proper way and make a video like this. But go further than just V1, and don't spent too much time on those CP tubes, it's so clear they are not on the same level. See what happens when also changing V2 and V3. And then swap the power tubes to blackburn mullard as well. Then you got yourself a recording amp instead of an everyday player.
Like he mentioned, the differences are so insignificant, not worth fussing over. If I had to go with one, I'd probably pick the Shuguang 12AX7B.
It's a faffing pain in the ass, but you can try opening another instance of the vid (i.e. in a new window) and then you can line up the sections/tubes you want to A/B.
Appreciate what he has done but someone should cut this video up to hear the same riff from the different tubes consecutively