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I know what you mean about the flopping. I played a 202N for 4 years and after switching to my current PT-6P I will never go back to rotors. I don't know if it's a universal experience, but to me they encourage flat fingered playing and I hate the way it feels while slurring. Just my two cents.

the elephant wrote: It sounds like this tuba had rotors that were not turning properly at the very front part of the section that rotates and was free for the remainder, and I HAVE seen this a good bit over the years. It can be due to filth/foreign matter in the casing, a out-of-true rotor spindle or a rear cap that is slightly out of alignment. It can also be caused by bent linkage arms or by a bent up paddle rack or pivot screw.

Rotors have a lot of moving parts and are easy to mess up if you are careless with them (like some kids in a school setting). Unless the spring is BROKEN there ought to be no lowering of the spring rate whatsoever as the valve is depressed.

Think about it: New, LARGE, expensive, professional quality rotary valve tubas around school kids--Im surprised it functioned for you at all!

Going from pistons to rotors takes a bit of adjustment--but if you're truly more comfortable with pistons then your choice is clear. The first time I saw a rotary valve tuba was my teacher's Miraphone 186--I was totally hooked right then and loved how it felt when I got to play one--never looked back!

JJ

the elephant wrote:

Also, playing with your fingers curved is a piston technique to prevent your pressing the valves at an angle that might get them to bind up. They move up and down and you need to, too. Rotors use paddles/platens that travel in an arc and that do not require you to play with curved fingers. Also, the physical motion needed to operate rotary valves is about half that of pistons. There is NO physical reason to do so with rotors, whatsoever. Flat fingers are just fine on a rotary instrument. If you have a teacher who disagrees with me on that feel free to put them in touch with me on that one. I play with my fingers shaped however the valve tells me they need to be to make the motion as efficiently as needed. And that varies from horn to horn.

Interesting, I've never met someone who considered flat fingers to be ok. I suppose whatever works for you is the way you should play.

My teachers have always taught that flat fingers can make your technique muddy in spots and also damage the tendons in your wrist.

First: my tech English is limited, as it wasn’t the language of my studies in math, physics, and mechanics. And then these studies were 40 years ago.

But the I was pretty good in vector math, which is what applies here.

No point in the action of rotor valves is linear, but the force applied at any point is linear in its direction.

If we look at the crank, it should be positioned 45° off the main axis of the open bugle in its resting (open position. If the bumpers are worn or have ben shaved too much, it will be further from the main axis. That leaves a very short arm for the push rod to work on, so that the initial movement of the rotor will be sensed very resistant. That will be even worse, if any of the moving link surfaces need lubrication.

One especially vulnerable link is the one with the two T’s. They are hard to lubricate, and they will drag or lock-up if they get dirty. I use very thin oil for them, Blue Juice. And I apply it generously to sort of flush these links, which should be obsolete in modern production, but then I have many old instruments.

The dimensions of many rotor set-ups have been optimised for short strokes, but that also creates a good deal of vulnerability to mechanical hazards.

Klaus