Posted by Rob Perelli-Minetti on November 20, 1999 at 11:38:31:
In Reply to: Re: Conn Jumbo posted by Joe S. on November 20, 1999 at 01:58:23:
Joe, are you sure the 14K bore size is the same as the 20K? Per the appendix to the Tuba Source Book, the 14K is listed as a .687" bore, the same as the King sousaphones. That was the 'standard bore' for all King tubas and sousaphones going back to around 1930 (horns came in three sizes .620 (for cadet sousas and small Eb tubas), .687 for standard sousaphones,'monster' Eb and BBb tubas, and the Symphony Bass models (including the orchestra pit model), and .750 for the Giant sousaphone, the big 'Monster' rotary valve basses and, by special order the orchestra pit horn).
The old Conn 'standard' Sousaphone Grand 36K which preceeded the 20K was a large bore horn, but I'm not sure if it was .734 like the 20K or .750. The Conn Jumbos were apparently quite rare and a bigger bore than the King Giant, so they must have been .770 like the big recording tubas.