Posted by Rob PM on May 20, 2003 at 08:53:15:
In Reply to: Re: Re: Re: Mouthpiece Recommendations- Old Helicons posted by js on May 19, 2003 at 22:39:32:
The Conn Helicon (probably an 18K) much predates the 14K, which is a post WWII model. I don't know if any of the old helicon mandrels were used for the 14K.
I have an Conn Helicon in BBb (much in need of restoration). The most common Helicons were "Monster" size, which seems to translate into the .734 bore we all know and love from the 20K. The 20K itself simply a Sousaphone Grand 38K, substituting the 1930's patented 'short action' valves for the standard Conn pistons.
Bell size for the helicons is typically 22", where the 20K sousaphone is the 26" we've all come to regard as standard. Review of the 1920's catalogs, however, shows the standard bell size of the 38K Sousaphone Grand was originally 24". 26" bells were also available, and by the mid-1930s seem to have become standard. Jumbos had 28" bells, with 30" available.
There was a 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. I have not seen one of these, but based on the illustrations I have seen, I suspect that those 22Ks are the direct descendents of the Monster Helicon, since when I compared my 20K and 18K, they seem them bore sized until the last two or three brances, where the 20K becomes larger.
As to mouthpieces, I would start with standard Conn BBb sousaphone mouthpieces: A Conn Helleberg, Helleberg 7B or Conn 2 (same inside cup profie with a cushion rim), or their derivatives. I've typically used my Conn 2 with good results. If you don't find that big enough, you could try a Conn Chief or a Conn 1. (I think Dillon makes a Conn Chief copy) I have tried also a King 26 (standard issue on King BBb sousaphones and basses, including their Giant, from the mid-1920s until UMI took over King) on both Conn and Holton helicons, but did not like it.