Astell & Kern AK100 II High Resolution Single DAC Balanced Output 64GB Music Player. A new standard for listening to music was proposed while Astell & Kern were developing the AK100. They recognised that certain aspects of the AK100 needed improvement during research and development for a successor. While considering how to improve the AK100, they realised that there was a difference between measured audio specifications and what the customer felt sounded right. After much deliberation, their development efforts were focused on making the AK100 2nd Generation "feel" right rather than mechanically boosting technical specs. The original AK100 was developed according to audio specification standards, but development of the next-generation AK100 was developed to the "New Standard" of how the music sounds. And buy this Astell & Kern AK100 II High Resolution Single DAC Balanced Output 64GB Music Player Now £799.99.