Posted by js on May 20, 2003 at 09:24:38:
In Reply to: Re: Re: Re: Re: Mouthpiece Recommendations- Old Helicons posted by Rob PM on May 20, 2003 at 08:53:15:
The 14K may have formally appeared as a model # after WWII (I'm glad to take your word for it.), but my guess is the "smaller, lighter BBb sousaphone made in the late '20s and early '30s, a 22K which had the same bore as the 38K, but a 24" bell and smaller bell throat and main brances." was just about like the 14K, as the 14K also had a .734" bore and fits your description (italicised above) completely.
However one wishes to name those Conn sousaphones: "14K", "pre-14K", or "14K-like", the Conn BBb helicons that I've seen look just like "them" from the large branch down to the gooseneck (as pictured in my post).