I severely dislike those things. I had one of those double loop slides on the 3rd valve tubing of my German York. It was hard to move and would bend a lot, so I took it all apart and reassembled it with only one crook in the tuning slide, better braces, more braces, parallel slide tubes. It made slide moving a lot easier and the tubing much more secure.
I dislike those things to. I'm not sure what reasoning is used when designing tubas with the double loop slides. The Yamaha is a great example of my opinion. The newer Yamaha's have the double looped slides that we both dislike but the older ones just have a looooong slide. I played on one of those old styled ones and if you needed a bit of pull on that third slide it protruded as far as the bottom bow! That was a pain for me because I like to lean alot when I play. I think one of the reasons for that double loop is ergonomics. It makes the slide about half the length (aprox.). I do enjoy going to high school IMEA auditions and watching 15 kids with Yamaha 321's with that double looped slide put in backwards and walking around banging them into everything . I do like the job you did on this York. It seems to me that my little BBb Mirafone has a similiar wrap with two tuning slides for the third valve. Good job Kev.
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Holton 345 BBb 4V
Miraphone 188-5U CC
Meinl-Weston 45S F