Recently we did a quick comparison between the Astell&Kern SP2000, SE200, and KANN Alpha over on our YouTube channel.
You can read our full reviews of all three:
SP2000: https://bloomaudio.com/blogs/articles/astell-kern-sp2000-review
SE200: https://bloomaudio.com/blogs/articles/astell-kern-se200-review KANN
Alpha: https://bloomaudio.com/blogs/articles/astell-kern-kann-alpha-review