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Tubajug wrote: ↑Wed Nov 08, 2023 2:20 pm Man, I can't believe I started this thing a year ago! That's crazy...talk about a project horn...

I'll get pictures up later, but at the moment I've gotten the valve section put back together (including flipping the first valve slide) and I've procured a Conn 56J bell to use. I've almost got the bugle put back together.

I'm trying to source tubing to lengthen the main slide to compensate for the shorter bell. Pictures later!

I have projects from last year I haven't even started yet!

arpthark wrote: ↑Wed Nov 08, 2023 2:29 pm

Tubajug wrote: ↑Wed Nov 08, 2023 2:20 pm Man, I can't believe I started this thing a year ago! That's crazy...talk about a project horn...

I'll get pictures up later, but at the moment I've gotten the valve section put back together (including flipping the first valve slide) and I've procured a Conn 56J bell to use. I've almost got the bugle put back together.

I'm trying to source tubing to lengthen the main slide to compensate for the shorter bell. Pictures later!

I have projects from last year I haven't even started yet!

Haha, that's true. I do have other projects, but when I looked back at the time stamp on this thread I couldn't believe it's been over a year! Time really does fly!

Well, do keep us posted. You give us backyard/shade tree tuba mechanics some hope.

sousaphone ribs:

(Yes, I'm always in a hurry to move on to the next trashed instrument, but...)

- Rather than a Dremel, I grind their ends' shapes using a floor-mounted grinder (fast).

- I apply solder to one end's underside, and (aligning it and adding liquid flux) stab that end to the large-diameter end of the branch with the torch.

- (Obviously sanded and fluxed) I hold down the rib about two feet down, solder one side, and keep scooting my hand and soldering down the rib.

- I then go back and solder the other side (ie. no wire, but if I DO need a wire, I can use ONE wire loop, and continue to slide it down - rather than my hand - and re-tighten as the branch gets smaller at the other end).

Flipped first valve circuit:



Valve section (not perfect alignment in the third valve curly-cue, but whatever...people will be so awed by the fact that it's a helicon, they won't notice, right?)

arpthark wrote: ↑Wed Nov 08, 2023 3:20 pm Well, do keep us posted. You give us backyard/shade tree tuba mechanics some hope.

Haha, that's very kind of you. I am certainly "home hack" when it comes to this. I blame the internet...I probably would never have tried any of this stuff if it hadn't been for forums like this where I saw what other people do and thought "I think I could do that..."

Actually, I blame my tuba professor as well. When I bought my first horn (186 CC with four valves), he said he had an extra Alexander bell I could swap it out with. He also put me in touch with someone who could help me add a fifth valve to it. While neither of those things actually materialized on that horn, it got me thinking about modifying horns and then I found tuba forums! The rest, as they say, is history.

I met Norm Epley (NRE Brassworks) when I was in high school, and went to him for repair all through college, and was always fascinated by the frankentuba-ing he was doing. And such a nice guy, too. Fond memories of locking myself out of my truck during a visit and hanging out in his shop for a couple hours while waiting for my mom to arrive with a spare set of keys...

Here's a mock up I did with my botched bell in place. Now that I've got a 56J bell to use, it will be a bit shorter, but still a 20" flare.

As I've been on the hunt for tubing to extend the main tuning slide, the bore size of this instrument has been brought up with several people and I wanted to get your thoughts.

The valve section is 0.687 (King-sized) and the ID of the large side of the MTS is 0.750 (also King-sized). The bell is clearly from a Pan American sousaphone (Conn). Did Conn ever make instruments in this bore size? I always thought the standard Conn bore was 0.734. I have a whole Conn 14K valveset here, which I thought I would be able to use, but nope...

I also though Conn did round braces, whereas this has diamond-shaped ones.

Any thoughts on any of this? Thanks!

I got the valveset on last night. I think I'll add one more brace at the top of the third valve circuit to help stabilize it a bit more. Then it's on to the neck and bell and we'll be in business!

Well, it was a good weekend for this project! I was able to get it all together. I still need to put on the thumb ring, make longer ferrules (it plays about 30 cents sharp with the tuning slide out 2.5 inches), and clean it all up, but it plays! I'm planning on making the ferrules about 3 inches long. That will give me some room to pull and push in, I hope. I still need to align the valves as well. I just threw some new felts on it to give it honk.

The neck and receiver are from a Conn 14K sousaphone I harvested. I had to shrink the neck just a bit to get it to fit, but worked!


The bell is from a Conn 56J. I took my time cutting this this time around!


Here is it all put together:

Looks great.

Sent from my SM-S367VL using Tapatalk

I got some work done on the MTS extension this weekend. I tried to get the ferrules off, but they weren't budging, so I just used other inner tubing with a ferrule on it as the extension. It looks a bit odd, but whatever. If I really want to, I can slip some outer tubing over it, but I'm not super concerned. My arm will be covering it while I play, anyway.

The large side was a perfect match with the MTS on a 186. The small side was a bit more interesting.... the tubing is 0.687 bore, but the small side of the crook it connects to was a bit larger. The ferrule had been flared out to fit. Conn 14K tubing fit perfectly, so I used that as my extension. Each extension is about 3 7/8" long.



I taped it all up and stuck it in to give it a blow. With the slide out about 1/2" I was able to get it in tune. My friend in Omaha who has his own shop (lathes, everything) warned me that by shortening the bell end (tapered) and lengthening the slides (cylindrical) I would shrink my octaves. He was right. When I get the second line Bb in tune, the low Bb is a bit sharp. It can be lipped, so I'll just have to watch it.



Now all I need to do is get it soldered together, add some braces and the extension will be done! Then it's just aligning the valves and cleaning and polishing it all up. The end is near!!

Very common for second partials to be sharper than fourth partials. It's not easy to change the tuning characteristics of a contrabass tuba, even though some people claim that it is.
If it was a general rule that more cylindrical tubas end up with closer second, fourth, and eighth partials, then those should all be the same pitch on my cimbasso.

That's not much pull, in my opinion, for an instrument that may well be played outdoors in temperatures like 35° to 60° sometimes. That having been said, it's really common at outdoor gigs for everyone to just leave their tuning slides where they are, so...

Here's the short action lower mouthpipe tube that would - alternately - offer you some length:

https://mouthpieceexpress.com/catalog/p ... s_id=23824

Thanks for the link and the insights. I'll look into the 20K mouthpipe and maybe add that in the future. As with most of my projects, I'm trying to do things on the cheap (teacher pay, six kids...). I've already spent way more on this than I planned to since I botched cutting the first bell I had, then decided to go with the 56J bell instead of the Monster bell...

My goal is to have this up and running for the usual tuba stuff played in December, some indoors, some out.

@ParLawGod might be able to help you with this one:

Quite a few years ago I made a double loop gooseneck for a Conn sousaphone which was converted to a helicon. The helicon played sharp even with a super long tuning slide extension. I told the owner of the helicon that - once they received this double loop neck from me - they would need to shorten the instrument in order to get it up to pitch, but all of that length would disappear and it would actually play flat enough. They never altered the instrument, according to what I've heard. Sadly that person passed away recently. You might be able to acquire that double loop neck for a very low price and then you too would have to shorten the legs coming out for your main slide. I can't find a picture of it online with the search words that occur to me. I bet Jeremiah - who I tagged here - has seen that neck.

bloke wrote: ↑Mon Nov 27, 2023 10:15 am @ParLawGod might be able to help you with this one:

Quite a few years ago I made a double Loop gooseneck for a con sousaphone which was converted to a Helicon. The Helicon played sharp even with a super long tuning slide extension. I told the owner of the Helicon that once they received this double Loop neck from me, they would need to shorten the instrument in order to get it up to pitch, but all of that length would disappear and it would actually play flat enough. They never altered the instrument according to what I've heard. Sadly that person has passed away recently. You might be able to acquire that double Loop neck for a very low price and then you too would have to shorten the legs coming out for your main slide. I can't find a picture of it online with the search words that occur to me. I bet Jeremiah who I tagged here has seen that neck.

I want to say he sold that instrument, BUT I'm not 100% certain of that. He listed some things for sale a half a year to a year ago, but not sure if they actually went. I'd be happy to inquire at some point.

An inquiry would be appreciated!

Thanks to you both!

It probably added 10 - 12 (??) inches of length, so (to have used it) they would have had to have SHORTENED their instrument (rather than lengthen it).
I explained this on the front end, but - I'm pretty sure - I was told that "it plays flat" and they never did what (again: on the front end) I explained would subsequently be required.

Also, it was tapered (from the same large-end bore to the same small-end bore) throughout.