Early Eb Tuba by Conn

This Eb tuba, serial number 2392, was made in 1879 or early 1880, just months after the break up of the partnership between Conn and Eugene Dupont.  Conn and Dupont made their first cornet in 1876 and were making larger instruments including tubas within a year or two.  This particular valve design was patented in 1879 by Conn and Dupont together even after the partnership was history.  The design is very simple and clever, allowing for a very light and small piston and making the action very quick.  These have two passages through the pistons rather than the three needed in other piston valves (five holes rather than six).  The woodcut from a Conn catalog below shows one of these pistons next to a standard Perinet piston.  The catalog calls it the "Equa-Tone valve" in some cases and "Conic Clear Bore Valve" in others.  The goal was to eliminate restrictions in bore through the pistons that was common to all Perinet style piston valves, shorten the stroke and reduce the weight, resulting in a lighter, quicker valve action.  In the up position, the air column makes a very sharp 180 degree turn inside of each piston but without constriction.  When depressed, the bore goes through the piston twice, once straight through and the second takes two 90 degree turns. The only weakness that I can see is that there is actually a slight bulge in the bore in that second pass.  I would assume that this valve design was short lived because the standard Perinet piston valves were thought to be superior in that the air makes shorter turns inside the valve.  This is fallacious thinking and my experience is that Conn instruments with this valve design have excellent playing qualities  I'm surprised that Conn dropped them and no other maker seems to have taken up the design.  This particular tuba has had a rough life, suffering abuse and unskilled repairs, making it not very playable.  I've never done any repairs or restoration work on it.  It is 30 1/4" tall, the bell rim diameter is 14 1/2" and the bore measures .620".  This is small by modern standards but is quite typical for the 1870s and 1880s.  I played an almost identical tuba, belonging to Mark Metzler that was in better shape, in a brass band concert in a reconstruction of Conn's band shell in Elkhart, Indiana (photo below).  Even with my weak playing ability, it played the bass line nicely.  
All the instruments used in this concert were made by Conn in the 1870s, '80s and '90s.  The close up photos of the bell to the left, show some interesting details.  Conn's bells were all made with a gusset, or triangle shaped piece, added to the bell flare to help form it's shape.  In this case, there is a second, smaller gusset added beside it.  In addition, there is a circle of brass, visible under the engraving.  These two pieces were brazed in during the original manufacturing process, presumably to repair mistakes.  The bell maker must have had difficulty forming the bell, tearing it at the gusset and kinking or creasing it further down on the opposite side where the brass is compressed during this work.  This required the circle to be cut out and a new piece added.  Having made bells myself, I understand how easily this can happen.  When the brass is thoroughly polished, these brazed lines are hardly visible but when tarnished and deteriorated with age, they stand out clearly in these photographs.  This tuba was obviously engraved by Jake Gardiner, Conn's early famous master engraver.  His style and quality are unmistakable after seeing a few signed examples.  Conn set the trend in the industry, with elaborate high quality engraving on every instrument.  Other US manufacturers followed suit very soon.  This tradition lasted until about 1970, when it became too expensive to have  engravers on staff in a world that builds to a price point rather than competing in quality and esthetic.