The Astell&Kern AK100 Portable music player seems to be the ultimate sound generator that can fit in your pocket. Believe it or not I was thinking aboot making a music player using Raspberry Pi, a sound card and a USB flash drive. This device does not quite equal that solution, but the packaging is way better and the software all sorted out. The missing link in this device there is no up converting of low bit rate recordings. This means to get the best sound you need to start with high bit rate recordings. On my home system I hear the greatest difference when I shift between analog cables and Optical cables. USB cables should give the same sound quality. So if you can hook the USB up to your car stereo I would expect a big difference between using this device and a I phone With a list price of $700 will I ever buy one, likely not, but its something to consider. So my dream of making the ultimate player which would cost around $300 remains alive.
I asked I river just to be sure, and my understanding was correct.