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Here's a horn I will have access to when I go to Wisconsin for a Dixieland concert. I know very little about Conns. When my friend sent me the picture I thought it was the 6/4. I mentioned that to him and he said "It's smaller than the Yamaha 4 valve or my dad's old Besson. The BBb Yamaha mentioned belongs to the high school/school horn.

So, is this the Conn 4/4 recording bass?

Any info is appreciated!

I'm grateful that I won't have to worry about flying a tuba. My BBb does not have a hard case.

TJ

6/4.

Play "open" F - at the bottom of the staff - with 1-3 (to avoid assaulting the band's sensibilities) and - probably - E-natural 1-2-3.

That 2nd valve needs a thin felt added on top of the thick cork underneath the valve CAP (CAP, not fingerbutton).
Piston alignment - with those - is critical. Someone else will explain why.

Someone else - in this tread - will also outline for you the (somewhat complicated, compared to all others) procedure for unscrewing and reinstalling the valve cap.

It’s a Conn 20j. bloke’s description is pretty spot on.

Some people recommend shoving a Conn sousaphone bit in the receiver. I don’t know what that helps, if anything.

They were designed to play with a bit. Most of the bad rap these guys get about the crappy fifth partial can be fixed but playing with a bit and proper alignment.

The thing is an air hog and not easy to play, but my God they are so much fun.

Well, the good thing is I have a friend in Pensacola with the same horn. I can arrange a short session with his so I know what the future holds. I hate to hear it's an air hog. I like pulling off long connected walking lines on very few quick breaths. If i'm huffing and puffing folks will think I'm over the hill... well I am but it doesn't show too badly on a smaller horn. tj

A 20J with no leaks, no dents in the leadpipe, valve tubing & knuckles will play reasonably well in tune and not necessarily be an air hog. Excessively large mouthpieces with oversized bores and throats are often culprits in excessive air use with this kind of horn. They can be played reasonably softly without too much effort, or can rattle a room.

' never experienced a bad fifth partial with these instruments, but the two highest pitches of the third partial are of no use, maybe unless the drums are really loud.

I've never found them to require nearly as much effort to play as (just as an example) a Rudolf Meinl 5/4 with one of those huge mouthpipe tubes they used to put on them, but I'm not the one who claimed these to be air hogs, I just pointed out that F and E are unusably flat - when played open and first valve.

Since the piston alignment is so critical, so many of these have been school-owned, and so few so-called "techs" of the past seemed (??) To have understood aligning pistons, and only understood the purpose of felt washers being to make valves quiet, I wonder if those that were judged to be "air hogs" could possibly have been epically misaligned...(??)

Maybe it's time to take mine in for service, but it takes me a lot more breaths to play things on my 20j than on a 20k sousa or my 186. Maybe I need to reconsider my mouthpiece choice as well? Use it with a RT50, which is my all purpose go to.

Since the question has been answered, I just gotta say:

I always thought it was C. G. Conn, and not I. D. Conn...

PT-50 is a mouthpiece that a lot of people purchase. I've gone through a number of mouthpieces that required a good bit of effort for me to make them run a tuba, but - at the time - I didn't have anything to which I could compare them, and just thought that's how mouthpieces for large tubes were supposed to be. Even with my own mouthpieces, I've recently downsized two of them that I use with two of my instruments, with very positive results.

An 8.3mm throat - as reportedly featured featured on a PT-50 - is not the largest I've ever seen, but it's larger than anything that I personally use, and - with my 6/4 size B-flat instrument - I'm using a mouthpiece with only about an 8mm throat. I suspect the comparative tapered back-bore diameters on this mouthpiece I'm using are probably noticeably smaller as well, as maybe are the comparative diameters down inside the cup. I'm not using a narrow interior opening rim (33-1/5mm's of my lips are exposed), and the cup I'm using is not shallow, but the mouthpiece itself is anything but something I would describe as featuring "blown out" dimensions.

I view a really nice sounding quick responding low range as one of the most important features of a big tuba. I like having access to those features without beating myself to death.

Good advice. I will try some others out

gocsick wrote: ↑Fri Mar 01, 2024 6:47 am Maybe it's time to take mine in for service, but it takes me a lot more breaths to play things on my 20j than on a 20k sousa or my 186. Maybe I need to reconsider my mouthpiece choice as well? Use it with a RT50, which is my all purpose go to.

The bore of a 20J tuba is larger than the comparable 20K sousaphone. You’d think they’d be the same but no.

I used to have a 20J. I really enjoyed playing it. Never put it in the air hog category. Big sound! Excellent trad jazz horn.

The 20J bore size is just about the same bore as Miraphone 186, Meinl-Weston 25, the old Meinl-Weston 20, and several other familiar models of (not 6/4) tubas.

It's something like .765" (??), which is less than 1/2mm larger bore than all of the 3/4" bore / 19mm bore tubas.