iFi Pro iCAN Professional Studio Grade Fully Balanced Headphone Amplifier and Line Level Preamp with Tube and Solid State Output Circuits The Pro iCAN will for many be used as a top of the line headphone amplifier that drives anything and everything from CIEMs through to the most difficult to drive headphone ever made, the AKG K-1000 It operates with full differential internal signalling, meaning the signal always remains two separate signals of equal level but opposite polarity The very first of its kind that has two individual input circuits: one tube and one solid state 3D Holographic for Headphones provides not only out of head placement of the sound sources, but renders the whole sound field in a manner that strongly parallels listening to loudspeakers in a normal room, all achieved without the added reverb