TubaForum.net

https://reverb.com/item/63622356-used-m ... a-sn-09674

That has the smaller valve set it appears. Little more hand friendly.

That appears to be priced right about where those things sell. ❤
Quite a while back, I picked up one of those in gleaming condition way too cheap. It played wonderfully, but - instead of keeping it - I took advantage of the price that I paid and flipped it. If I lucked into the same sort of deal again, I probably put a smaller mouthpipe on it and keep it.
I'm thinking that they later went to the larger diameter pistons as some attempt to imitate old York tubas, but both the small diameter and large diameter feature significant convex distortions in the cross-porting - distortions which do not appear in those ancient super lightweight and extra long York pistons.

bloke wrote: ↑Thu Dec 01, 2022 7:49 am If I lucked into the same sort of deal again, I probably put a smaller mouthpipe on it and keep it.

You just lucked out because somebody was selling a really nice-lookin' Thor around here-- oh wait.

Also a good candidate for those MAW pistons.