I have grado sr325es headphones and i use them with my ipad mini 4. I feel the sound is great, i have read on whathifi that these headphones should be connected to a dac/amp like audiolab m dac for best sound quality. I managed to test the mdac with my headhones and wasn't able to hear any difference, maybe the dac that is built into the mini is sufficient enough to get the best sound from the grado headphones without the use of the mdac? the grado's sr325es are known for there amazing detailed sound, surely headphones as good as this don't need help from a dac to sound better, these are already 5 star headphones. an opinions on this? thanks