I have an iPad air, and it is great. I am normally good with identifying problems and fixing them but I'm not too sure about this one. Whenever my iPad is on charge and I have my earphones plugged in (I have tried it with many) I hear a low pitched buzzing/humming noise, which can get annoying if I am trying to listen to something. Interestingly the buzzing stops when I touch the aluminium casing, so I am assuming that it is an electrical issue if it is an issue at all. Many thanks