Astell&Kern AK HB1 Portable Bluetooth DAC/AMP (Shadow Black)Experience the Freedom of Music, AK HB1 AK HB1 is a portable Bluetooth DAC/AMP that lets you effortlessly experience high-quality audio and Hi-Fi streaming services with the best performance, all without the hassle of cables. Pair your mobile device to AK HB1 through Bluetooth and experien..