It is merely a state of the art of the late 70’s / early 80’s – design, manufacturing, features – like no other at the time and long after.
Check out other members of the family: Atari 410 Tape Recorder and Atari 810 FDD.
Atari 800 is powered by 9V AC of a pretty high rating, according to this article, it can be up to 3A depending on the power supply type. In the absence of the original power supply, a replacement from a Guitar Effect Power Box with 2A rating works pretty well.
A fantastic machine i must own someday. Its design is so state of the art like you said. A must have and must play with 🙂