It is very annoying. I have taken over the mage tower in central Ilishnar and killed many many golems. The drop seems to be 1 in 10 for music gears. With 1 out of 10 being an uncommon. I have no idea how rare the rares are because I never received one. I can tell you that paragon golems are the only ones that can drop a rare gear. However they can still drop a common.