American Valves for EU Tuba Manufacturer?

[BrassoProfundo]

Am I crazy (full disclosure: the answer is generally yes...) but,

In my recent late night tuba research, I half-recall that I encountered a comment mentioning that one of the leading German tuba manufacturers has begun to source (perhaps experimentally?) rotary valves from a state-of-the-art US manufacturer.

This may have been a comment by Hiroaki Shiromi, tubist Osaka SO, on one of his tuba reviews (https://www.youtube.com/@shihandai. Or... I can't recall.

I've always heard that the best rotors were made by Miraphone and Yamaha. Please correct/update me, if that's no longer (or ever was) the case.

I was half-asleep. Am I completely projecting or misremembering this?

Thanks!

Adam

[BrassoProfundo]

Which raises another question: what are the best sources of information on valves, rotor, piston, etc? It seems this has to be gleaned from a variety of posts and discussions at a variety of sites about people's experiences playing various tubas. That's one wildly diverse source of info which I wonder: is there some resource which distills all this qualitative social chatter? And, what about the tech side: occasionally I see someone with tech chops, engineering and applied physics weigh in. But that's rare, and recondite. Of course, this is all part of the larger question of horn design, which seems like its mostly a matter of perception, training, trends. How it actually applies... to the tuba playing public? Is anyone studying this stuff on a grander scale? Sharing their research?