Rotary vs Piston

[dsteinerz]

What are some of the pros and cons of piston and rotary valves?

[Three Valves]

I've always played pistons and like them.

When I play a rotary, the arching motion of the paddles freaks me out because I'm just so used to the pistons moving in a direct, linear fashion.

That's my story and I'm not changing it!!

[NCSUSousa]

.

[tbn.al]

Pros play pistons and cons play rotaries.

[Dan Schultz]

I like rotors. 1. shorter action. 2. Less picky about where you put your fingers, and when you have LARGE hands like I do, that makes a difference. 3. For my tubas, when a rotor needs oil, it gets noisy, not sticky, so there's less chance of them screwing up at a bad time

What he said.

The only real downside to rotors is that they are easy to neglect since they require so little maintenance to keep them going. However... once neglected to the point that the rotor bearings are badly worn... they are difficult to fix. One can swage the bearings but keeping the tolerances on the seal surfaces where they belong can be a daunting task.

Pistons can be easily replated and refit.

[Donn]

Back in the day, I think we used to believe that rotors were more manageable at large bore sizes. Because you can adjust the finger travel as needed, where with pistons you can adjust the stroke length only by squashing the valve ports. I guess as what we might call a second order consequence, a piston valve set in an equally large tuba might tend to be located nearer to the receiver where the bore is smaller, so the notes that use a lot of valve would be going through smaller tubing. King vs. Miraphone.

[Dan Schultz]

Pistons can be easily replated and refit.

Rotors can be plated with copper or copper and then nickel to the same effect. We often use that as a solution for instruments worth the time.

FWIW.

I've found it to be a real pain in the *** to refit replated rotors as opposed to refitting replated pistons.

[TBow]

Taking a tangent to this discussion, why do compensating horns (Using the Blakely (sp?) system) always use pistons? It seems to me the same effect could be done with a double rotor similar to what some double French Horns use. That would remove the need to play the 4th valve with the pointer finger of the left hand with your arm wrapped around the horn. I expect cost to be one reason but with "name brand" horns costing $6,000 or more, how much more would a double valve system cost?

[Dan Schultz]

Rotors can be plated with copper or copper and then nickel to the same effect. We often use that as a solution for instruments worth the time.

FWIW.

I've found it to be a real pain in the *** to refit replated rotors as opposed to refitting replated pistons.[/quote][/quote]

With the emphasis being placed on the 'worth the time' aspect.... I agree! However.... I've never had a rotary horn in my shop that I've considered to be 'worth the time'. The only exceptions might be some of the very rare horns where replacements are not available... such as perhaps the rotary Kings. Luckily, none of those have needed much rotor work.

I ran across a VERY old (probably pre-war) St. Pete a while back and had the rotors plated. Refitting all of the rotor surfaces proved to be agonizing. The plating cost was quite low but the hand-work turned out to be waaaay more than I was interested in doing. As far as I'm concerned it was an experiment turned very bad and I ended up buying five brand new rotors for much less than I would have invested in labor.

Never again will I attempt to go beyond simple swaging of rotor bearings or minor lapping! If I have a rotor that is truly worth the investment to rebuild... I'll send it to someone else.

[pgym]

I expect cost to be one reason but with "name brand" horns costing $6,000 or more, how much more would a double valve system cost?

Given the labor, tooling, and R&D costs, more than a manufacturer could ever hope to recoup.

[Rick Denney]

Miraphone and Hirsbrunner both built double-rotor three-valve compensators of the Blaikley plumbing type at one time or another. I played around with the Miraphone--this was maybe 35 years ago. Can you say "heavy"?

As to the matter at hand: The main difference between rotors and pistons is that the former were invented in Bohemia (modern southern Germany and Czech Republic) and the latter in France. Both were invented so long ago that both have received well over a century of refinement and work very well.

Beyond that, it's preference.

Rick "who has tubas he likes, and they come with valves" Denney

[Three Valves]

Pistons are French??

Uh Oh.

[OldsRecording]

Pistons are French??

Uh Oh.

Oui, monsieur, ils ont été inventés par François Périnet, qui était français.

[Three Valves]

That's it.

I'll take my cars, machine guns and tuba valves German, thank you!!

[bort]

That's it.

I'll take my cars, machine guns and tuba valves German, thank you!!

Well, I've got 2 of the 3 covered...

[Donn]

No decision is possible.

[OldsRecording]

What about Vienna valves?