Rotary valves and rotating direction

[tbonesullivan]

This video does a pretty good job of showing the internal rotor structure. I should also note that the orientation of the valve and valve tubing changes whether you want CCW or CW rotation. On a trombone with an F attachment, the valve tubing is on the opposite side from a tuba, so the Clockwise rotation is desired. Due to how the linkages work, it was much easier to make the second valve in an independent bass trombone rotate the opposite direction.

I should note that in the video, the "conventional model" they are comparing the YBL-830 to is its predecessor, the YBL-613H.

https://youtu.be/R93fvioIZ28?t=118" target="_blank" target="_blank

[P@rick]

The rotation of the rotary valve impacts the slur articulation of that valve. A valve which rotates counterclockwise (set up as rotors typically are in rotary tubas) will engage the extra tubing without directly interrupting the column of air. A very smooth legato articulation can be achieved with the valve. A valve which rotates clockwise will have a much harsher articulation because the bridge between the channels of the rotor itself must cross the incoming air stream while engaging the extra tubing. The resulting articulation is a much more solid articulation more akin to a tenudo than a legato...

A good explanation! A agree that it makes a difference, but Bloke just made me realize that it does not matter for Tuba...

...Rotary valves rotate two ways. After they rotate one way first, they rotate the other way next.

I didn't think of that myself, but it absolutely makes sense. The valves rotate in both direction so it basically does not matter much from what rotary direction you start...you also have to come back and rotate the other way to play the other note...

It’s not my job in my life to try to convince people - who believe things that I don’t believe - to believe the way that I believe.

You can call it "convince people", but I call it sharing facts or opinions. I like to hear both and that's what makes this forum great. Keep "convincing"

[tadawson]

The other thing I note is that you don't play through just one port on a valve! No matter which direction it turns, one of the two ports is going to have the rotor web crossing over it . . .

[NCSUSousa]

I gave 2 example companies to look at in my previous post who make their rotary tubas this way. Google is not your friend at this level of detail.

I googled, but could not find any.

Here's an image Wessex (source https://wessex-tubas.com/collections/cc ... hler-tc470):

Note that ALL of the rotary valves will spin in the same direction (even the 5th valve) on this design.

Here's an image from Miraphone (source https://www.miraphone.de/instruments/tu ... valves-307):


Does it really make slurring easier? There are already enough posts on that topic.

[P@rick]

I gave 2 example companies to look at in my previous post who make their rotary tubas this way. Google is not your friend at this level of detail.

I googled, but could not find any.

Here's an image Wessex ...Here's an image from Miraphone...

Thanks for sharing!

[Art Hovey]

A valve which rotates clockwise will have a much harsher articulation because the bridge between the channels of the rotor itself must cross the incoming air stream while engaging the extra tubing. The resulting articulation is a much more solid articulation more akin to a tenudo than a legato. In some cases, you can audibly hear the valve cutting the air stream with a small "tph" sound making the articulation.

When I hear that "tph" sound on my rotary-valve tuba I know it's time to clean the sludge out of that valve. When it's all cleaned out I can blow through the tuba while moving each valve paddle and feel no difference between the clockwise and the counter-clockwise rotors.

I suspect that the origin of this urban legend is the fact that engaging the third or fourth valve suddenly puts a lot more air into motion than doing so with the first or second valve, because of the longer valve tubing. That extra air has extra inertia. Maybe some folks are sensitive enough to feel the difference, and perhaps they mistakenly attribute it to the difference in rotation direction.

I am still trying to figure out whether the author means clockwise as viewed from the front, or from the back of the tuba. Does anybody know?

[NCSUSousa]

I am still trying to figure out whether the author means clockwise as viewed from the front, or from the back of the tuba. Does anybody know?

I don't see that the author of the 1st post specified. Since my response did specify, I'll give my opinion.

I've always treated CW/CCW rotation as viewed from the audience, not the player or the linkage. Trying to view it any other way can get confusing since the valve linkages don't always face the same way depending on which hand operates the 5th valve:
Here's an older Miraphone 186 with a left-hand 5th valve (and the old style 3rd/4th valves):

If anyone cares, it's for sale in Durham, NC (not mine to sell and I don't work for the guys selling it).

There are also oddities like this one from Alexander that's got a valve setup more like a Horn:

I haven't seen one of these up close to know which way it rotates.

[P@rick]

I am still trying to figure out whether the author means clockwise as viewed from the front, or from the back of the tuba. Does anybody know?

I don't see that the author of the 1st post specified. Since my response did specify, I'll give my opinion.

My question was about the difference in directions of the valves and why. Most Tuba models have (had) mixed valve directions and that was my point.

But for the question "what is clockwise" for a valve? In my opinion, you should look to the valve from the side where the linkage is attached, regardless what the front and back from the Tuba is.