ROTARY VALVE BESSON 981

[eeflattuba]

Cruising the web today I have noticed that a few british tuba players have had their piston 4th valve replaced with a rotary 4th valve. They claim that it really opens up the lower register. Is it possible?

[Steginkt]

Even without the added low register, it looks like it could easily improve the ergonomics of your machine

[cambrook]

Mike is a clever guy, there's information on his website

http://www.mike-johnson-custom.co.uk/cu ... index.html

The MJC 4th valve conversions came about, almost by accident.
We were approached by a player who was having physical difficulties. The doctors had told him to stop playing.
Not being a large fellow, the stretch round a standard, compensating EEb was causing the nerves in his shoulder muscles to detach from the muscles!
We came up with a plan: replacing the standard 4th valve with a rotor, so the lever could be much closer to the player, and alleviate the stretching.
What we didn't expect, was that this completely opened up the traditionally stuffy 4th valve register! The 'kickback' commonly experienced with the 4th valve register is all but non-existent, allowing truer intonation and truer colour to the sound.
Result: A compensating instrument that is as open as a non-compensating instrument*.

[EdFirth]

I have always thought that rotary valves of the same bore were more open blowing than pistons. the ports on pistons begin and end at different altitudes on the piston and there are the "bumps" to accommodate the other ports around them. While rotarys are a straight shot through the valve casing.I have wanted to add a fourth rotary(bigger, of course) valve to many horns that I've encountered because the three valve versions of so many Conns, Kings, Yorks, and Holtons play so well and are far more plentiful than four valved ones. I've played Conn 12J' and 5J's,King 1240's and 1241's, Holton(the based on the York model) with both valve sets and every time the 3 valves were more centered and open sounding. And if you see them side by side the fourth valve set up looks like an afterthought squeezed in there with tight bends. These are just my observations, not really scientific research but the results have been consistant. I've also read that some of the big Holtons came with the fourth valve bigger from the factory and seen top banger Martins with a loop between the third and fourth valve(to allow for bore expansion?) What I really like about doing it to a Besson is that it frees up your left hand to work the first slide, if you are so disposed.OK, I'm done now, Ed