Conn 14K with a larger bore

[pjv]

Howdy,
I've been scratching my head on this one.

From everything I've gathered the Elkhart 14K's should sport a .734 bore, certainly one from the 60's.
I recently bought a 1966 (an H78xxx) 14K, but it's bore size is larger than that of my 40K and my 1913 Conn BBb Monster.

The 5th valve slide on my Kanstul 80 F tuba is also listed as having a .734 bore, so assuming that this work of modern science was correctly measured I used the fifth slide as my measuring stick and compared it to the second valve slides of the 14K, 40K and the Monster. The 40K and the Monster checked out with the Kanstul 5th slide, but the 14K is larger. I also checked the other valves just to make sure.

It's not that much larger, but enough to make swapping out parts impossible. Since I haven't found this phenomenon mentioned before I thought I'd post it here, hoping that one of the TubeNetters can help out.

Thanks, Pat

[pjv]

This is the 14K with my 40K, Monster and 36J for fun.

[pjv]

On the left the 2nd valve slide of the 14K which just won't go into the Kanstul 80's 5th valve slide port.. The 1st and the 3rd valve slides from the 14K have the same measurement.

The picture on the right is the 2nd valve slide from the 40K which does go in. Not pictured here are the Monsters slide, which also goes in, and a comparison of the 14K's slide is which is still much smaller than the .770 bore of the 36J (for the record.)

[iiipopes]

Hmmm. It's pre-Macmillian, so that is a mystery. Worn mandrels/dies/hydraulic tubing forms?

[pjv]

And even still, the 14K's got thinner at some point (smaller bore), not wider.

Curiouser and curiouser...

[pjv]

Hmm, then my guess is that Conn was using up parts left over from a special order. There's nothing to suggest that this particular tuba is special. Even though it's not marked as a 14K, everything about it points towards that model.

I found it for $325 at a secondhand shop that had listed it on the internet as a trombone (no wonder it didn't sell within a day). The neck and bits they sold me were from another instrument, so I'm using a 1930's neck&bits which work fine. For the rest the instrument was ready to play, right down to the water key cork. It sure was cleaner on the inside than most of my horns.

-P

[aqualung]

Get yourself some calipers, and measure the I.D.

[tofu]

Great price - how does it play?

[pjv]

The horn plays great, actually. The metal is thinner than on the 40K and the 14K's last leg and bell throat are smaller. This makes the horn real easy to play from high to low and quicker in response than the 40K. The intonation is much easier, evener and more in tune. The less in tune notes are also easier to place were I want them, even on the fly. Since I spend less energy getting the 14K to play in tune (and just to play in general) my precision in playing is greater compared to the 40K.

Down side; I miss the mature sound of the 40K which is really a joy to hear. As well the 40K produces a weightier sound than the 14K. I also miss the full bodied lower notes that a forth valve offers.

These observations are probably obvious if not public knowledge. It is of coarse a triumph to have found a tuba for real cheep which also plays great! Its never happened to me so I guess it was my turn.

-P