Yamaha Custom YSL-841 (nominally a straight .547). However, this one has been customized, largely at the Yamaha factory from what I can tell.
I also assume the original owner had the straight tuning slide as well at some point, but that's just speculation.
In any case, it's a .525/.547 dually, rose gooseneck and bell in 8.5". It plays great! The linkage is actually quite well set-up and not hard to use.
I haven't noticed anything really odd about how the horn plays or responds yet, other than a pretty sharp 6th partial. I do actually quite like the sound, and I'm using it tonight on something... we'll see how it works.
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![Image](https://i.imgur.com/TxkRa3g.jpeg)
![Image](https://i.imgur.com/ucsYG1r.jpeg)