info on a king 2350 silver 1981 sousaphone

[solomon]

Hi ,
I got hold a of a beautiful king 2350 silver sousaphone. It plays great with a beautiful sound.... but it didn t came with the original tunings bits and neck. These are "modern" king parts... anyway, my problem is, this horn for my is really sharp, the tuning slide almost falls out. Could this high pitch have anything to do with the not "original" tunings bits and neck?

thanks