

The valve is one that I bought for about $5 more than 40 years ago from the junk pile in a music store in Switzerland; the tubing is mostly from old sousaphones. The large-bore tubing makes the instrument much less stuffy and mellower-sounding in the low register than a regular Conn 15J, for example.
Routing the extra plumbing in front of the pre-existing tubing has several advantages: it affords a resting place for the thumb which is much more comfortable than a thumb ring, it offers some protection for the pistons, and it makes possible a very long 4th tuning slide. This slide can be pushed in to make 12&4 exactly in tune, can be pulled out to make 4 alone in tune, can be pulled some more to make 2&4 in tune, or can be pulled out still more to make 4 alone work instead of 2&4.






