For a history of the mellophone, see this article on Al's Middle Brass Pages.
To see pictures of Don Elliott with mellophones, organized by type, click here.
The Conn 14E "Classic" Mellophone (image from The Conn Loyalist)
The Conn 16E Mellophonium (image from The Conn Loyalist)
The mellophone is a brass instrument that, although usually pitched in F and often looking somewhat like a French horn, has little else in common with that instrument. The mellophone has an octave less tubing but approximately the same range because the French horn plays on its higher partials. It is also smaller and is played with the right hand. Paul Gaspar, a trumpet player in the Rochester area, describes the mellophone's sound as a cross between a trombone and a flügelhorn. Indeed, an unaccustomed listener could easily confuse it for a trombone.
The circular mellophone, also known as the classic or concert mellophone (source), was the original shape of the instrument but is rarely seen today. Although used classic mellophones can be found on eBay, they are no longer manufactured in quantity.
In live settings, however, Elliott disliked the classic mellophone because its sound did not project out to the audience but was instead directed backwards. He asked Conn to build him a custom bell-front mellophone to fix this problem, reportedly at the suggestion of Dizzy Gillespie. Conn did this in 1957, creating the horn that Elliott would use from that point until it was stolen, probably about three years later. In 1960, Conn made Elliott a second custom mellophone, and they made him a third in 1962. These two horns are owned by Don Elliott's estate, and Jeff Stockham, an instrument collector in upstate New York, has another one, which was made around 1959, apparently for someone other than Don Elliott. He described how he came to possess it in an email to me on July 23, 2011:
After making Don's custom mellophone, Conn invented the 16E mellophonium for Stan Kenton's band, and other companies imitated it. Don promoted the Conn 16E on the Steve Allen Show and in Conn advertisements.
Today, the most common type of mellophone is the marching mellophone, which is used, of course, by marching bands. Unlike older mellophones, which have cornet-sized mouthpiece receivers, it has a trumpet-sized mouthpiece receiver .