I was thinking the same thing these days. I have been using the Mojo with my HD-600 or 650, so 300 ohm impedance. Then a few days ago I tried it with my Nightowl, much lower impedance. Wow... all of a sudden I realized that I need to either a) go into airplane mode - which I can't since I stream from Qobuz or b) get a much longer cable and keep the Mojo the hell away from the phone. Didn't expect the buzzing to be so severe.