This Tuba Tuesday’s feature is the oldest C. G. Conn double belled euphonium in the Museum’s collection, circa 1889.
Double belled brass instruments (also called duplex instruments) were first made in Italy in 1847.
The American maker C. G. Conn, which was founded in 1874, made double belled brass instruments - alto horns and euphoniums, but mostly euphoniums - beginning in the 1880s all the way up through the 1950s when the English compensating euphonium became the preferred instrument by American soloists who had up until then played the double belled euphonium.
This Conn double belled euphonium circa 1889, shown below, has an 11.5/8 inch primary bell and a 5.3/8 inch secondary or “echo” bell. It also has four piston valves, but the fourth is only used to change from the large to the small bell.
https://simonettitubacollection.com/ins ... -piston-2/