Posted by John Swensen on June 28, 2001 at 18:49:37:
In Reply to: Reducing valve noise posted by Steve on June 28, 2001 at 05:03:00:
Steve,
There are many kinds of valve noise, with varying loudnesses.
Probably the loudest noise is caused by metal hitting metal, usually because the felts are worn through (clack, clack, clack as the valves are depressed and/or released). Obviously, the felts should be replaced (possibly corks, too), and the alignment checked with a dental mirror.
Worn valve guides rattle if you (gently) twist the valve button back and forth; these sometimes will rattle as the valve is operated, particularly if you tend to apply a twisting force along with the down force. Valve guides can be replaced, but it is not always easy to figure out how the guides come out (some are soldered in place, some screw into the side of the valve, some fit into the top of the valve).
Loose valve caps (top or bottom; usually top) will rattle or tick when the valve is operated. The third valve cap on one of my tubas rattles unless I really screw it down tight, and has been that way since the horn was new). Sometimes very heavy grease or wax on the threads will quiet this rattling down.
Springs that are bent or not sitting straight may buzz when the valves are actuated; this is caused by two or more coils of the spring vibrating against each other. Carefully straightening the springs so they stand upright often helps this problem, but new springs can be an easier solution. I suppose that springs much longer than ideal might make noise if they were compressed so far that all the coils hit each other. Shorter springs with slightly larger diameter wire might solve that problem. You can rule out spring noise by removing the spring and operating the valve by pushing it down and pulling it up (if the noise goes away without the spring, the spring caused the problem; otherwise, something else caused it).