Posted by Rob Perelli-Minetti on October 06, 2000 at 21:06:52:
In Reply to: Re: Conn tuba on ebay posted by DC on October 06, 2000 at 11:07:09:
This is NOT a small bore horn if it is a Grand Orchestral. The bore on the Grand Orchestral is at least .750, if not .770. Alone among Conn basses, it was never made in an upright valve model because it was felt impractical (according to early literature).
There was a Grand Orchestral in BBb for sale a year or two ago on e-bay that went well over $3000, with both it's original 23" bell and a smaller 20" German (meinl weston?) bell.
These horns are uncommon at all, and quite rare in CC.
As far as I can determine, Conn basses came in 4 bore sizes:
The smallest, the "junior" basses was probably close to the .659 of the modern 2/3/4/5J CC and BBb tubas.
The next size, "monster" was the .689" that is very typical of American tubas in the 20th century.
The large size bore corresponds to the .734 of the 20K series of sousaphones and 20J tubas and the older Sousaphone Grand (38K and 40K with 4 valves) and lightweight Sousaphone (32K).
The largest size seems to be either .750 or .770 for the Grand Orchestral tubas, possibly the 36J Recording Bass (though that may have been a .734 bore like the later 2XJ series) and the 48K Jumbo Sousaphone Grand. BTW, that 9" throat sousaphone on e-bay is probably a 48K Jumbo