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Just a curious question. I am NOT going to try this but I was having a conversation with a fellow tuba player. And I was wondering how many inches of tubing you have to cut off to make the conversion. How many inches fro mthe main part? 1st, 2nd and 3rd valve?

This is a link to Art Hovey's "Tuba Logic" website:

http://galvanizedjazz.com/tuba.html" target="_blank

Art has provided much information about length of tubes, tuning and many of the physics of sound needed for brass musical instruments.

Art also posts here frequently.

For starters, you'll need to remove 24" from the open bugle of a BBb tuba to take the fundamental pitch up to C. Beyond that, you will also to remove a PROPORTIONAL amount from all of the tuning circuits. The percentage that you will need to take out of the individual tuning circuits will be about 24 divided by 432.

Cutting the tuning circuits is just a matter of mathematics. Getting 24" out of the open bugle without causing problems with the taper is another matter altogether. Some tubas have main tuning slides AHEAD of the valve cluster. At first glance, this appears to be an ideal place to begin cutting. However, you need to remember that you STILL need a main tuning slide!

Something to consider.... a CC tuba has an open bugle 30" LONGER than an Eb. Sometimes it's less trouble to make and Eb into a CC instead of from a BBb. Just an option.

Buy and old 'beater' and give it a shot. Have fun!

Every EEb to CC conversion that I've seen has not been good. It may be easier to add 30 inches of cylindrical tubing to an EEb to make a CC, but it is, from my experience, not better. Has the "Tinker" done or seen one of these that was successful?
Sam-who's working on a 6/4 BBb to CC conversion of a Martin with a Cerveny Kaiser bell and a 5-valve .687"(1-3),.734"(4),.750"(5) bore valve cluster.

Sam Gnagey wrote:Every EEb to CC conversion that I've seen has not been good. It may be easier to add 30 inches of cylindrical tubing to an EEb to make a CC, but it is, from my experience, not better. Has the "Tinker" done or seen one of these that was successful?

Nope. I've not done it. Nor have I seen a working prototype. I figured there must be some folks out there who have tried it. I'm only alluding to some of the experiments done where the tuning slides were removed from old King BBb sousas to get 'closer' to a CC.

I have, however... done some experiments adding 24" of cylindrical tubing to a CC to make a BBb. AKA.... Miraphone used to sell a conversion slide that didn't work all that well. Other manufactures have 'tinkered' with the idea, too.

I agree with you.... adding copious amounts of cylindrical tubing to ANYTHING probably won't get great results. However.... if the motive is to just 'cross over' from EEb to CC, it might be a 'quick fix' to allow a person to at least get used to the fingerings.

There are already enough 'stinky' horns out there without deliberately creating more beasts that won't play. Maybe one day we'll have all the 'stinky' stuff re-created into descent playing horns!

About adding tubing to a CC to make a BBb: One of the guys in Indianapolis that owns a horn I built had me build the 5th valve short enough to put the horn in BBb. He plays CC most of the time but wanted to also use the same horn on brass band BBb parts. I used a very extended crook end slide that would interchange with the 3rd slide. By moving the long slide to the 3rd and the shorter 3rd to the 5th it placed the horn nicely in BBb with the 5th valve depressed. And it plays great as a BBb.

Sam, that sounds like a really cool project. I WILL own one of your horns one day!

Keep in mind that a really fat tubed horn is shorter than one that is cylindrical.

I'm not going to pretend I know much at all about this, but I remember a conversation Tubatinker and I had, sort of along this line. It was focused on how the aperture (bell) dimensions will affect the pitches a flared tube will produce. A very general (and beyond my ability to quantify) rule, as I understood it, was that a bigger bell will "increase" the overall (um, is focal the right word?) length of the tube and make it flatter, so the tube must be shorter than for a horn with a smaller diameter bell. That could make fitting a tuba with a bell different from the original a much trickier project than just getting the "inches" of the bell section right.

Did I get that correct? And is this related to the phenomenon Elephant mentions, quoted above?

At any rate, it pretty much discouraged me from ever cutting a horn myself. Meddling with the primal forces of nature like that is best left to experts.

Carl Kleinstuber has done the Eb to CC conversion, successfully. That's all I really know about it.

eupher61 wrote:Carl Kleinstuber has done the Eb to CC conversion, successfully. That's all I really know about it.

There was a King Eb/CC conversion for sale at BBC a while ago and discussion here was that it, too, was OK.

With all this shrinking and stretching, I think the builder has to start with a good candidate. Sam has made so many CC horns from King 234X bodies that the King must be a good place to start. When I had my 2340, I could see how the material could be cut out of all of the inner branches without having to take more than 3 or 4 inches out of one particular tube, thus not messing with the taper as much as taking more out in one place.

A few months ago, someone posted picture of a conversion of a 20J to CC that looked not as straightforward as on other horns. Some of the branches had to be tapered severely. The builder said it worked fine, though...

Morrell wrote:Just a curious question. I am NOT going to try this but I was having a conversation with a fellow tuba player. And I was wondering how many inches of tubing you have to cut off to make the conversion. How many inches fro mthe main part? 1st, 2nd and 3rd valve?

Hi I have cut (2) Conn 24J to CC add a 5th rotor, Also a King EEb sousaphone to CC conversion by add a longer main tuning slides and adding a longer 4th tuning slide all the slide are removeable and the CC sousaphone goes back to EEb. You may think the CC longer Main tuning is too long and gives the horn out of tune notes But on this horn it does not! and Customer who wanted the work done is very happy with King sousaphone and both the Conn 24Js. I would love to put pictures on But My pictures are to big and I just don't know how is made then smaller BUT you can blog Harvs Happy Horns cutting a 20J to CC were you can see a few pictures Thanks Harv.

The Big Ben wrote:... With all this shrinking and stretching, I think the builder has to start with a good candidate. Sam has made so many CC horns from King 234X bodies that the King must be a good place to start. ...

Well.... using the King valve parts is certainly not a BAD place to start. However... I'll venture a guess that the REAL reason why those King parts are so popular for conversations and 'Frankenhorns' is because there are more of those valve sections flying around that any other valveset except for perhaps the Conn 14/36K sousa valve sections. Abundant parts make for good prototyping. Each horn using the same basic parts just gets better and better.

I know.... I know.... the Conn 14/36K are only three-valved horns. But... they are quite easy to add a fourth valve to.

the elephant wrote:Keep in mind that a really fat tubed horn is shorter than one that is cylindrical. A euph is not as long as a trombone. So a BBb BAT will need a bit less than 24" removed (a bit being maybe as much a three or four inches less). A really skinny BBb that is right at 18' in length will need the full 24" chopped out. My Holton 345 is only 15' 7" long, so a proportionally shorter section must be removed to being it up to a 440 Hz CC tuba and more to get it to play in the 442 (or higher) calibration used in Europe. Bone up on your math! Go to Art's great website, too.

Your statement puzzles me, Wade!

You are right about the wide-belled tubas being shorter than they should be expected to be from calculating the length of the oscillating air column.

But isn’t that because some shading effect of the bell flare moving the node out in front of the bell?

By your argumentation the slide loops of the Chicago Yorks should be shorter than those of a YCB-621. I never saw any suggestions pointing that way.

Klaus

imperialbari wrote:But isn’t that because some shading effect of the bell flare moving the node out in front of the bell?

No, it's mostly because of the taper design, which causes the wavelength/speed of the sound to vary as it proceeds down the instrument.

The bell is just a part of that process, but the conical bore has an even bigger effect.

Rick "recalling the discussion with Dr. Sloan a few weeks ago" Denney