The objective of AK 380 (Astell and Kern) is, while keeping the original sound, to realize the professional functions as well. Extended AMP integrated with design, DNLA-based AK connect app and metal touch. As the metal touch that plays the role of a home key is pressure-sensitive, it is operated by the fine pressure of the metal when the metal touch area is touched lightly. AK 380 is extendible to a wide range of devices using the micro USB terminal and the balance out terminal at the bottom of the product. AK 380 offers an improved sound quality by regenerating the original sound without down-sampling of 32 bit 384 kHz.