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Hi all...

I currently play on a Willson 3200RZ F tuba with 5 Rotax rotary valves. The instrument is spectacular in every way except that the valves are quite sluggish. My all-star repairman and I have tried many different valve oils (of course cleaning when switching), tightening and loosening valve springs, completely changing valve springs and lapping the valves. This instrument features Willson's Rotohead linkage (good idea, unbelievably finicky and over-engineered) and I have made tiny adjustments until I am blue in the face with no noticeable difference.

To any Willson rotary tuba owners...have you experienced this with your horns? To the TNFJ, do you think that replacing the Rotohead linkage with a UniBall linkage would help with the speed? I would hate to dump the money into the upgrade if doesn't help.

Any other advice? Are the valves themselves just too heavy? Thanks in advance for your help and ideas.

Andy Rummel

SF

My memory is quite distant at this point but I feel like I recall a Willson rotor F *many* years ago at the army conference that was built with the rotor bodies at a 90 degree angle to what is customary such that the linkage to the valves was very very short and direct. Spatulas were directly above the rotors.

Like this:

The action on that particular horn was outstanding so I think it's perfectly possible to have great action from the rotax rotors.

I agree with you that the linkage on those horns is WAY over engineered and frequently a source of problems. If it were my horn I would be very tempted to replace the linkage with a high quality uniball(not the miraphone stuff). The Miraphone uniball stuff is inconsistently machined and can be alternately too tight and stiff or sloppy and clanky. The too tight ones can be worked loose over time but the sloppy ones are a lost cause. The MW stuff is more robust but occasionally sloppy, even on new horns.

In an ideal world I would love to have carbon rotors from these guys: http://www.jm-gmbh.de/html/e_meinlschmidt_tuba.html

Looks like they now make a 'radial flow' valve for trombones: http://www.jm-gmbh.de/html/e_meinlschmi ... _news.html

If they upsized that valve, or copied the rotax or kanstul rotor in carbon that might be ideal.

Food for thought.

I know some may think this is tacky, but I used rubber bands on the 186 BBb I was fortunate enough to play in high school. Just wrapped one end around the (ungreased) 2nd valve slide ring, and the other end to the linkage itself. I seem to remember the professor I was studying with really laughed when he saw it, but said it was indeed a quick/cheap fix. I used one rubber band for each valve, they weren't very tight; just tight enough to make a difference.

Hope this helps.

Please send that mirphone 181 to...

joh_tuba wrote:In an ideal world I would love to have carbon rotors ...

Carbon is the tensile element in the composite. Given very little tensile force applied to rotors, I sort-of don't understand why the expense of carbon is necessary.

But the bigger issue is thermal expansion. The epoxy that holds the carbon fibers together is just thermoset plastic. It's been tried: Hirsbrunner built plastic-cored rotary valves once upon a time, to make them light. On hot days, they locked up tight. If they were loose enough not to, then they leaked on cold days. No plastic will have the same thermal expansion rate as the brass casings.

Better were the Cerveny rotors from back in the early 80's, which were hollow as I recall. I seem to recall they were made with a shell and ports the same way as piston valves.

As for linkages that are neither too tight nor too loose, give me $25 worth of Du-Bro ball-ends, some threaded rod, and some brass tubing.

Rick "nothing new under the Sun" Denney

If the problem is actually the weight of the rotors, then that can be measured. You could located/purchase/borrow some kind of small scale and compare them to something else. I suppose that would assume that you have or can borrow something to compare them to.

This cross section of a rotax rotor doesn't look especially chunky:


The linkage does look stout.


Tony Clements has a rotary Willson CC, maybe you guys can compare notes.