Razer leviathan mini making humming sound.

Hey, I recently bought a leviathan mini. More than impressed by the sound it produces and all that, but for a while after I stop playing music/movie it makes a humming sound, it stops after a while and soon as I play audio it starts, so if you listening to something at low volume you can hear it at a short distance. It isn't obnoxious but I would like to know why it is doing it. It did it over 3.5mm and bluetooth ( using a 4.0 A2DP adapter not aptx which I will order if it fixes it ). If need more information just ask.