Udi wrote:As I was cleaning my souzy from a dusty gig I played yesterday I checked the valves sealing by pulling the tuning slides out without depressing the valves. Instead of that lovely "pop" sound I heard air flowing in, though they did gently poof when they got free. How do you repair this and check for other leaks? Is this one of those "it's a sousaphone" cases too?
No, valves should fit well even on sousaphones.
Mine were pretty dry, which didn't help. The only way to really know if the valves are causing a problem is to use a heavy oil, like motor oil. The valves won't work well, of course, but it will seal them up good. Then test the intonation. If there's no difference, then clean out the motor oil and replace with regular valve oil. You might try Hetmans Classic which is a bit thicker and designed for older instruments with worn valves.
But I doubt that's your problem. Leaky valves usually cause the instrument to tend flat, not sharp, in my experience.
Rick "with a collection of leaks at the moment" Denney
