Posted by John Swensen on January 12, 2000 at 16:17:36:
In Reply to: problems with hirsbrunner rotors posted by Bill on January 12, 2000 at 16:08:06:
Someone I know has an older Hirsbrunner with the same problem in hot weather. Apparently, the rotors were plastic, which expanded more than the brass. He ended up replacing the entire valve block and fixed the sticking, but may have ruined the horn's intonation.
My understanding is that Hirsbrunner went to titanium rotors and fixed the sticking problem, but I don't know when they changed. Why not contact Peter Hirsbrunner and ask him?