Kanstul Confusion

[pjv]

As many TubeNetters know, Kanstul has been busy at work designing new tubas. I originally wanted to post a topic asking if anyone had compared the sounds, responses and characteristics of the 90-s and the 66-s.(I found only one short note from UTSAtuba in the forum history). I just assumed that the 90 is the BBb brother of the 66; they look the same, don't they?

Checking out the CC 90 4/4 spec's, it's listed as being .689" / .710" 4th / .734" Rotor Bore; 19" Bell
The BBb 66 4/4 is listed as being .656" / .689" 4th / .710" Rotor Bore; 19" Bell

Wait a minute; two almost identical horns and the BBb is, well, thinner? Anybody have an idea as to whether or not this was a technical decision (in order to get the best results out of both horns), or did it have another reason?

True, Kanstul has the Mammoth-ish BBb 900 5/4 .689" Bore; 19" Bell

(Funny enough this is called a 5/4, but thats beside the point.)

Its starting to look more like a question for Kanstul than for the TubeNet. Still, I am curious if anyones played two or three of these models side-by-side.

Cheers, Patrick

[mammoth2ba]

Kanstul has the Mammoth-ish BBb 900 5/4 .689" Bore; 19" Bell

If we're talking about vintage Martin Mammoth BBb's, that bore size is closer to 0.720".

It's the piston King BBb's (1240, 1241, 2340, 2341) that have 0.689" bore.

[Timswisstuba]

Checking out the CC 90 4/4 spec's, it's listed as being .689" / .710" 4th / .734" Rotor Bore; 19" Bell
The BBb 66 4/4 is listed as being .656" / .689" 4th / .710" Rotor Bore; 19" Bell

Wait a minute; two almost identical horns and the BBb is, well, thinner? Anybody have an idea as to whether or not this was a technical decision (in order to get the best results out of both horns), or did it have another reason?

On CC horns the bore gets bigger quicker because there is less length, whereas on BBb's the bore taper can be more gradual.

[iiipopes]

Yes, the BBb is copied more on the old York, which had that small a primary bore.

[pjv]

Howdy,

Thanks for the info gentleman.

The Mammoth design reference was something I read on Lee Stofer's site.

"This instrument (the 900) is based on the measurements of the old Martin Mammoth recording bass, arguably making it a 6/4 size tuba, but with the .689" bore..."

Cheers,
Pat