A vs. E shank--backbore different?

[MichaelDenney]

I recently bought my first tuba with a large European receiver, a 6/4 Holton 345 BBb.

How do mouthpiece manufacturers accommodate the larger receiver? Do they increase the OD of the shank but leave the backbore the same as in the American shank? Or do they increase both the shank OD and the backbore? Or what?

In looking at the single E shank mouthpiece I have so far, a Dillon M1CB, it appears that the maker could possibly have added meat to the shank up near the cup while at the same time keeping the shank wall thin at the very end.

Anybody have the skinny on this?

[Ivan Giddings]

’m glad somebody has brought this up. Shank size changes the total gap from the end of the mouthpiece to the end of the lead pipe. This gap when changed will change how an instrument plays drastically. A very easy way to test this at home is to wrap some tape around the shank of your favorite mouthpiece ( maybe twice around the shank with electrical tape, not a lot) and then play the mouthpiece on your tuba and notice how your tuba and plays different.

So what is the size difference from a standard shank to a euro shank. This depends on the manufacture. However we use .520 for our standard shanks and .538 for our Euro shanks. So how does .018 change the gap? For every .001 the gap moves about .007. In the case of Euro Vs Standard shank this means the gap changes about .126. This is interesting I’m sure, and if I haven’t put you to sleep just yet a piece of paper is about .003, so go stack about 42 pieces of paper and look how thick this is, this is roughly .126 thick. This difference in gap is noticeable and will affect your instrument in ways you never imagined.

Some folks like a Euro shank mouthpiece on their standard receiver tuba, and sometimes just the opposite is true. However the proper gap on your instrument will greatly improve everything.

We do change the back bore to match the Euro shanks as well it may only be a small amount, but this makes the end of the shank thinner and less of a speed bump for sound waves that return back through the instrument to your lips and give you feedback.
I hope this helps

Ivan

[Kevin Hendrick]

... So what is the size difference from a standard shank to a euro shank. This depends on the manufacture. However we use .520 for our standard shanks and .538 for our Euro shanks. So how does .018 change the gap? For every .001 the gap moves about .007. In the case of Euro Vs Standard shank this means the gap changes about .126. This is interesting I’m sure, and if I haven’t put you to sleep just yet a piece of paper is about .003, so go stack about 42 pieces of paper and look how thick this is, this is roughly .126 thick.

Also, if you have a ruler handy, .126" is about 1/8" (a little over 3 mm if you prefer metric).

[MichaelDenney]

Thanks for the answer, Ivan. Many here appreciate the inside view that you bring to discussions.

[Dan Schultz]

Many of the European horns don't have a receiver, anyway. The leadpipe has a formed taper and there is a reinforcement ring on the end. Therefore.... there is no gap because there is no joint between the leadpipe and receiver.

[MichaelDenney]

I must not understand what the definition of "gap" is. Is it the distance from the end of the mouthpiece shank to the end of the leadpipe, the annular space between the OD of the shank and the ID of the leadpipe, or what?