Fostex HP-P1 Headphone Amplifier Digital connection from iPod/iPhone to HP-P1 via 30-pin dock connector High quality 32-bit DAC (AKM4480) and headphone amp for maximum sound quality S/PDIF Digital Out for professional recording Hi/Mid/Low 3-step gain control on the headphone out drives all headphone types Auxiliary analog Line Input for other MP3 players