TubeNet

Before the pandemic, I decided if I was going to continue playing tuba, I would need a smaller lighter instrument. I was playing my 1928 Martin Mammoth at the time and due to age, the horn was getting heavier and heavier and too much for a man in his late 70". I purchased a new Miraphone 191 4v BBb due to it being considerably smaller and compact but capable of producing the full sound I like. The valves on the 1928 Martin are lightening fast despite their age and full stroke design. The Miraphone is a nice playing instrument but the rotary valves are just plain slow. I would have expected greater speed over the Martin. I played a big King rotary in college back in the early 60's and don't recall valve speed being an issue. Since the 191 was new out of the box, I assumed speed would improve with break-in. That doesn't seem so. I do like the 191 but find the rotary speed slow for my taste.

Perhaps others have had similar experiences and can offer some suggestions other than going back to piston valves.

Thank you,

Mike

I hope my experiences help you?
I played pistons only for years. I played music that had lots of notes at great speed. The pistons kept up.
I now have two horns. Both have pistons and a rotary.
One of my tubas has no linkage to the rotary. It simply has a lever attached directly to the end of the rotary's shaft.
I have measured the actuation force as 1 lbf, with pistons being more than double that. It is light. It opens. It closes. It does it all very quickly. It may be better than a piston.
My other horn has linkage to the rotary. The rotary is a slightly larger diameter.
The rotary, here, is sluggish. It requires a lot of effort to actuate. It is oiled and maintained as it should.
Pistons don't have all this mechanical linkage. I use pistons only when playing swiftly on this second horn.
Both horns' rotaries are made by highly reputable European manufacturers.

If I did own a horn with soley linkaged rotaries, that were sluggish, I would take it to a specialist repairer and maintainer, asking ".... can these be made quicker?".
All the best,
Geoff

Goeff, Thanks for the reply. Interesting that the fourth valve on this instrument needs just light pressure from my pinky and is very quick in response - markedly faster than the first three valves. If all the valves worked like #4, I'd be a very happy camper.

mroettersr wrote: ↑Thu Aug 26, 2021 5:38 pm Goeff, Thanks for the reply. Interesting that the fourth valve on this instrument needs just light pressure from my pinky and is very quick in response - markedly faster than the first three valves. If all the valves worked like #4, I'd be a very happy camper.

There is no reason why they can't all work like that. Are you using rotor oil or something similar inside the rotors. Try using a lighter rotor oil. Or nothing at all, as Miraphone recommends. And a lighter oil at all the mechanism points than whatever you are currently using.

I have a 191 available to me right now. The rotors are VERY fast.

If these changes don't help, you should go see a tech.

Hello again,
Been an engineer for longer than I can remember. Engineers always look to fix things and to innovate. Natural to us.
The mechanism operating the rotary is mechanical. Things rub. Things creak. Things twist. Things are tight, then loosen over time.
They require lubricating. They require maintaining.
Each valve and its mechanism is unique, just ever so slightly different to its neighbour, so even if they look the same, they are not.
That is maybe why your #4 is better than the rest.
Use of a linkage oil may help and might be the solution, as I mentioned in my first post, but I would still take it to someone to check over, as it may need encouragement to be as quick as you want it to be.
*********
Innovation: when I look at the mechanics of the linkage, I just think to myself "bearings", and not just in the obvious places. An idea worth consideration especially when you think how much these horns cost to purchase. - Bearings can be tiny, light, sealed for life............. friction is a devil of a thing in mechanics......
*********
Cheers and good health to all, Geoff

GeoffC_UK wrote: ↑Fri Aug 27, 2021 1:47 am
Been an engineer for longer than I can remember.

Innovation: when I look at the mechanics of the linkage, I just think to myself "bearings", and not just in the obvious places.

Cheers and good health to all, Geoff

And the same part can be both bearing and seal, whether intended or not. I would prefer to separate functions as far as possible.

The oil I am using is the oil Miraphone shipped with the horn. I used the oil on the rotor bearings and all the moveable joints. There can be friction in the return springs as they wind and unwind so I lightly oiled them. Things remain largely the same. My late friend, Ivan Hammond, had given me the name of a tech that he trusts at a southern Michigan shop not too far from where I live. My next step should probably be to contact him for advice. I am very mechanically inclined but would like to go into this well informed before taking a chance screwing something up.

Mike, good thoughts. I'm sure it'll end up being great, Geoff

I, too, have a 191, purchased a few months ago from a highly reputable, experienced source. My rotors are too slow, as well.
My previous 6/4 and 5/4 tubas were piston horns, and they were light and speedy. My current 3/4 tuba is a piston tuba, and again is very speedy. I would like my 191 to operate as lightly and as speedily as those piston horns.
I do notice an improvement in rotor action when I pour a cup of warm water through the mouthpiece and out the tuning slide to clean it, as recommended by Miraphone, but it's not enough.
Please post your solution when you find it! If your solution is to trade into a 1291 I wouldn't blame you one bit, as I keep thinking the same thing.
Thank you.

This is the third try to post a response. I don’t know where the posts are going. I have sent a note to the dealer who sold the 191 to me to see if he has any insights on the matter of sluggish rotary valves. I decided on the 191 over the 1291 based upon sound and my positive experience with the 3 rotary valve King monster I played in college back in the 60’s. I am happy with the 191 with the exception of valve speed. If I learn anything, be assured I will post it.

Mike

One comment that was in an attempted post. There was a 191 advertised on this site a couple months ago. In the photos posted with the ad, I noticed that valve and linkage assembly wasn't quite the same as the newer tuba I have. I don't know if this is a factor in one respondent saying the valves are fast while another has the same experience as I have with new instruments.
Mike

Miraphone valves and factory linkage are nicely made and, when in good repair, very light and fast.

No one on the internet can fix your valves with words. Contact the seller if you’re within their trail period and a competent repair professional if not.

As a matter of follow-up, I did get good input from a couple people via e-mail. On the lower rotor cap, there is a very small screw in the center of the cap that I mistook for the hole found in the lower cap of piston valves. A very small star screw drive bit allows that screw to be turned in and out. Turning the screw out relieved pressure and valve action quicken significantly. Another respondent suggested removing the lower cap, gently taping the bearing base, reinstalling the cap, and gently tapping the top pivot. This supposedly reseats the bearing which along with oiling and adjusting the set screw further improved the rotor action. I have yet to pour warm water down the lead pipe as suggested by Miraphone but that too should result in more improvement. The seller was very helpful resolving this issue. I thank the people on TubeNet for the input.

mroettersr wrote: ↑Fri Oct 15, 2021 12:17 am As a matter of follow-up,....

Sounds good progress

Yeah, that valve adjustment on the rotor plate should be in a good positing when Originally set by Miraphone, but things can change in shipping or different temperature. I’m glad it’s working better, but if still a worry, and experienced tech should be able to fine tune it to meet expectations.