Conn 14H Duo-Bore Medium Bass with Rotary Valve to F & E-Natural
Date: 1929. Owned by Louis Allen
This is definitely a 14H: it is clearly stamped "14H". It does look very similar to the 70H Duo-bore base of the same period. The 14H was essentially a smaller version of the 70H, with a #3½ + #4½ bore, which is a 0.522" + 0.547" (yes, my table has #3½ at 0.515", but a late 1920's Conn trombones catalog clearly gives it as 0.522"). The bell size is 8½". This model 14H was produced between 1927 and 1932.
Interestingly, both of my late 1920's catalogs have the 14H without the rotary valve in the F attachment to E natural that this one (and the 70H) has. This leads me to believe that Conn included that rotary valve, like in the 70H, sometime probably in 1928 or 1929. Conn's description below is of the version of the 14H without this additional rotary valve, hence the reference to the extra slide for E natural. On this instrument the addition of that extra rotary change incorporates that E-natural slide and activates it by turning the knob. Tuning is in the slide. The advantage of having the tuning slide in the slide is that it allows the bell to be completely conical while putting the tuning slide, which is cylindrical by necessity, in the slides which of course are cylindrical as well.
This is the only model 14H Duo-Bore Medium Bass I have ever seen or heard of, and I don't expect to come across another again.
What Conn said in 1927/1928:
The Bass Model Trombone, as made by the C.G.Conn, Ltd. has been recognized for many years as of surpassing excellence. The Bass Trombone is an essential investment in any large band or orchestra. In fact, its value in Symphony Orchestra has made it indispensable in musical works of the higher order for the past century.
The 14-H is an exceptionally flexible bass trombone. It possesses the Rotary Valve change to F and is supplied with an extra crook to change the instrument to E natural.