The harp player in our band has an old Hohner 12R solid state amp (it actually sounds pretty good). Anyway, I changed out the old two prong cord for a 3-prong. While I was in there, I noticed (what I took to be) a death cap attached to the fuse and removed it. The amp now has a slight noticeable hum. I know NOTHING about SS stuff! I'm thinking this may be an old cap issue, but would appreciate any insight into this I can get.