Adding an un-traditional 4th valve

[Rick Denney]

How do you decide where to add the valve? As late as possible in the bugle to allow for larger tubing?

It usually depends on what rotor you find, and the tubing that can go with it. And where there is a place to mount the rotor without having to perform major surgery. If you can find a straight section of tubing withing reach of the valves, in a place where the rotor can be serviced, that is a diameter that matches a rotor and tubing that you can obtain, count yourself lucky and don't worry about how much bigger it is.

Some tubas have larger fourth valves than the other three (such as my Holton) and some have increasing bores through all four valves (such as my B&S). On the Holton, the larger fourth makes it almost too open for me. On the B&S, it makes the low C fit in the scale of the instrument. On balance, I'd probably want it to be close to the third valve just to keep it from blowing too differently, but that may add one-too-many requirements to the above list of requirements.

And if you can't do it with cheap surplus parts easily enough to be within your skills or to take a pro tech very little time, then it will be too expensive to be a reasonable alternative to just buying a four-valve instrument in the first place.

Rick "who once bought a valve and tubing for a similar project before coming to his senses" Denney

[tbn.al]

But I'd be interested in learning anything about this.

IMHO the very best way to go about this is to contract with one of the pros who are sponsors on this site to add it for you. The cost is about $1000 usually. You will cost yourself much more than that trying to muddle through all the issues.

I bought a sweet little turn of the century Conn stencil Eb that Lee Stofer had converted to a 3+1 setup several years back. It was a remarkably good playing horn conversion and all. There are others who can do this kind of work as well, Lee's just the only one I've had experience with. The right pro will consult with you and help you through the pros and cons of valve placement, type, bore size, lever placement, etc.

I've been seriously thinking about having Lee put a 5th on my Miraphone, but what could I buy an already complete 5v horn for?

[tclements]

You just have to be a little careful with this operation. If you are adding a rotary to a piston horn, it should go after the 3rd valve and the bore should be slightly larger than the piston cluster, but no TOO large, or it will throw off the open harmonics. There has been SOME success with adding the valve to the leadpipe, (like the CB/GB 50) but I would be careful cutting the leadpipe as this, too, can cause some harmonic problems. If you want to go this way, make a second leadpipe and take the original off, so if the project is a disaster, you can re-install the ORIGINAL leadpipe. Good luck.