To those who saw my last question about excess valve noise in my Sterling euphonium, that has been fixed and taken care of. It stopped after I replaced the felts (they were 8 years old and had been thinned). When I received the instrument, the springs inside were too wide and would not seat in the slot in the bottom valve cap. I originally replaced them with some Yamaha springs from a Yamaha YEP-321 made somewhere around 1980. They work rather well and their tension is light and comfortable, but due to the fact that they are a bit older, the third spring and fourth spring make noise somewhat randomly. I then tried replacing them with new Yamaha springs and these new springs made a very large amount of noise, and it almost seemed as if they were too strong for the valves. I then tried Besson springs (these were longer but lighter like the springs I first put in), and while there was less noise, there was still noise that I could very well hear that isn't supposed to be there. I take great care in making sure the springs are slotted into the groove in the bottom valve cap, so I don't know what is causing this noise. If anyone knows what is causing this noise, or if anyone knew where I could get a new set of the older Yamaha springs, that'd be great. Thanks!