Posted by Klaus on August 22, 2000 at 15:14:12:
In Reply to: Inquirey posted by Tony Clements on August 21, 2000 at 13:40:57:
Among my 30 brasses are a Kanstul G marching euph and a Yamaha YEP 641 euph.
Fundamentals aside the 641 is a larger instrument on following parameters:
Leadpipe bore, bore through valves, bore of the larger bows, and bell with/volume. Which is anything but length of main tubing.
The Kanstul G is an odd creature, but within its of frames it is logically made. It is not a Bb with some cylindrical tubing added to it.
Not knowing your intended use of a G tuba I can have no real foundation for creative thoughts on the topic. Still I will take what might turn out to be a very long shot:
Besson does make a rather small Eb in their 700 series. Frequently mistaken for being a euph. Not a very impressive instrument compared to the Besson 981 Eb. Still the bell and the 2 (or 3) first bows might be of interest for your project.
Depending on your preferences for 4 valve compensation or for a larger number of non-comp valves some hunting for a front action valve section will have to be done.
If you would like compensation, then a section from a Willson/Canadian Brass euph might work after a lengthening of valve crooks. I would not care to augment the length of the tiny 2nd valve comp loop.
Non-compensated valve sections might be trickier to get. The older US type bores of around .570 very well might prove being too narrow. Maybe a German rotary valve section might be a relevant answer.
Klaus