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Hello guys,

I have a pleasure in get a Conn 56J satin silver.
It is great horn and a beautiful sound but with some issue of intonations that is easy with alternatives fingers.

I'm in doubt about the progressive bore of the 4th valve.
I would like to explain and say sorry if I will not clear with my explanation.

When I was clean the valves I checked about the holes of the valves that are equal, and the 4th valve have the same measure of the hole than the first one.
I realized that the bore is graduate after the 4th valve (when it is closed) but the tubes when come back to the 4th valve to go to the tuning slide, there is a decrease of the bore for the same bore than it was started and after going to the 4th valve the bore increase again.

Ok.
If it is a graduate bore, the exit of the tubes of the 4th can not decrease into the 4th valve.

Why does it happen?

Thanks

Dante

I think Dante is saying the entrance tube for the fourth valve is larger, but the exit tube that leads back into the main bugle is the same size as valves 1-3.

The Conn 56J does indeed have the same bore through all 4 valves. The tubing of the 4th valve tubing was intentionally larger in bore so that there would be less resistance should there be any solder blobs or burrs during the construction process. It doesn't matter if you like the way the horn plays.

arpthark wrote:I think Dante is saying the entrance tube for the fourth valve is larger, but the exit tube that leads back into the main bugle is the same size as valves 1-3.

Exactly.

My question is: is it a graduate bore? Because only the tubes are large not the valve.

dantetuba wrote:
My question is: is it a graduate bore? Because only the tubes are large not the valve.

I think that this is exactly what Matt Walters addressed in his post just above yours. He designed the Conn 5xJ series for Conn-Selmer and has, I'm sure, worked on many of them in the shop at Dillon Music over the years. In other words, he's the authority on those instruments. The answer is no, the Conn 56J is not a graduated bore tuba and yes, the 4th valve tubing (but not the valve) does have a larger bore and he explained why that is. Like Matt said, none of that matters if you like the way it plays.

bloke wrote:I've watched it on Turner Broadcasting two or three times in the last couple of years...and yeah, it's becoming a bore.
Anne Bancroft, though, was pretty hot.

Dante is probably parsing this sentence word-by-word to figure what the heck it's about.

(I'm not so sure myself)

Hup

Bloke is referring to the motion picture "The Graduate" (as in "graduated bore-d")......

At least that's how I saw it......