Hi! , just bought the apogee One and every time i connect it to the power supply for using it with my ipad i get a hum sound ( listen to it in the link below), the hum only comes up when the one is connect to the power supply (if i connect it to my macbook using the usb for powering it the hum...

Thanks to everyone for helping me.  I bought the apogee ONE (the one that can be connected to the ipad) and the dt880 Pro 250 ohm last thursday and they sound really good.  The only problem is a hum sound (maybe a ground loop?) that comes up when using the ONE while connected to the power...

Thanks! Hope they work good. Do you know the difference between the dt880 pro and the premium?

Thanks! SAE Institute in Mexico city, is the best choice here in Mexico.

Hello, i'm going to study Audio engineering and as a requirement i need Professional headphones and the apogee one (or duet), i want to buy the beyerdynamic Dt800 Pro (250 ohms), do i need a headphone amp? or it will work with the apogee? Sorry for my english, is not my native language.