V-MODA VAMP: Integrated Headphone Amp, DAC and Battery Pack For iPhone 4/4S [video]

The irony of using your iPhone 4/4s as an “advanced audio device” dissolves when you consider the features packed into the VAMP. The solid metal case contains a 150mW x 2 amplifier, dedicated pure Digital-Analog-Convertor, VQ audio enhancements, optical audio output and a backup battery. Meaning iTunes becomes hi-fi Tunes.

The V-MODA VAMP Headphone Amplifier is available for $600 on amazon.com