Project advice...

[Peach]

Folks,
I have a small, squat model York Eb with the 14-15" bell. I want to get it up to modern(ish) playing standards. It started life as 3 top valves and I already flipped it to 3 front pistons. I don't think York ever made this size Eb tuba in that configuration. I used the valves from a York Monster Eb - ie. Very small bore (16mm I think).
Plays 'ok' as is, but quite tight so I'd like to open it up a little.

I have a 19-21mm 4+1 Eb valveset which I'm *thinking* of installing, BUT to match the bores would mean taking out the whole 1st branch and using cylindrical tubing around to the main slide (which would also be cylindrical).

I already have a good 3+1 Comp Eb so want this non-comp to be smaller, and hopefully maintain its good intonation(!).

So the advice (if anyone is still listening) I'm looking for is whether this would likely improve OR screw up aspects of the tuba??

The other option would be to install these valves on an older B+H Imperial Eb (and leave the York alone), but that would be essentially full sized Eb...

Any advice welcome!
Ta,
MP

PS. I could maybe add photos tmrw if that helps?

[roweenie]

The key is to keep the taper as unchanged as is possible.

With that said, 19 mm (.748) valves are way too large for that pea-shooter York, which IIRC, is probably a .625 (or @16mm) bore. Not only would they be mismatched, but as you noticed, it would be very difficult to transition from the bugle - you would actually be increasing the taper into the tuning slide, or at the very least, adding a lot of cylindrical tubing (not a good idea!), as you mentioned. Also, not as important but still a factor, don't forget that generally speaking, as the bore increases, so does the distance in piston travel - any benefit you might have gained from having a small horn (soloing, etc.) might be negated by a longer piston stroke.

Believe it or not, I would even hesitate to put that 19 mm bore valveset onto a Boosey Imperial E flat, as the normal bore for that horn is (IIRC) .689, or 17.5 mm. A King (.687) set would be much more appropriate for the Boosey, IMHO.

The trick, regarding that small York, will be in finding a suitable small-bore 4 piston valve side-action set (@.625, or roughly 16mm). Conn used to put this size valveset on their small sized E flat tubas. When you find a source, let me know, as I've been looking for one, too

You might be able to get away with using a Conn 5J valveset - the bore is .656, or roughly somewhere between 16.5 - 17mm (16.67 mm, to be exact).

Another option would be to get a set of four 16mm rotary valves....that would be a relatively simple solution.

Good luck, and keep us posted!

[Peach]

The key is to keep the taper as unchanged as is possible.

With that said, 19 mm (.748) valves are way too large for that pea-shooter York, which IIRC, is probably a .625 (or @16mm) bore. Not only would they be mismatched, but as you noticed, it would be very difficult to transition from the bugle - you would actually be increasing the taper into the tuning slide, or at the very least, adding a lot of cylindrical tubing (not a good idea!), as you mentioned. Also, not as important but still a factor, don't forget that generally speaking, as the bore increases, so does the distance in piston travel - any benefit you might have gained from having a small horn (soloing, etc.) might be negated by a longer piston stroke.

Believe it or not, I would even hesitate to put that 19 mm bore valveset onto a Boosey Imperial E flat, as the normal bore for that horn is (IIRC) .689, or 17.5 mm. A King (.687) set would be much more appropriate for the Boosey, IMHO.

The trick, regarding that small York, will be in finding a suitable small-bore 4 piston valve side-action set (@.625, or roughly 16mm). Conn used to put this size valveset on their small sized E flat tubas. When you find a source, let me know, as I've been looking for one, too

You might be able to get away with using a Conn 5J valveset - the bore is .656, or roughly somewhere between 16.5 - 17mm (16.67 mm, to be exact).

Another option would be to get a set of four 16mm rotary valves....that would be a relatively simple solution.

Good luck, and keep us posted!

Thanks for the reply.

So one extreme of tapers leaves one with a (straight) Cimbasso, and the other way, we get something like the (fast-tapering) CSO York.

If stuck a cylindrical branch into the little York Eb, presumably I'd just be taking it part of the way over towards Cimbasso-sound-land? Might not be so bad...

Clearly the only way to find out for sure is to tinker!

Re the B&H Imperial Eb, the wide side of the main slide is a good match for my larger bore valves so I'm confident they would work well enough. The Boosey valves make some jumps in bore between valve 3 and 4,and particularly after the 4th to (and through) the main slide.
The B&H Eb design has remarkably good intonation, given the taper expansion I'd say.

Thanks again...