OK so was using my new iPhone 6 64GB black, I have a spigen light case on it. Was using it in landscape in the dark and noticed a 'buzzing'. As its been quite warm here I thought it was a mosquito or something, so thought nothing of it. Doing the same thing today, and again I hear the buzzing. I then realise its the iPhone! It only does it when charging and I have tried different chargers (note I am using an iPad charger, but this shouldn't make a difference). I also got a similar sensation when charging the iPad Mini Retina, but that is common knowledge anyway. Has anyone else came across this, or can test this? Not sure if it does it on the plus? Note this only happens when charging, and you have to run your finger lightly across the volume buttons.