Let's try some Ash Ra Tempel, I thought. The surprise I was in for! Join Inn (1973) at first seems pretty normal sign-of-the-times spaced out psychedelic rock. And indeed, 'Freak 'n' Roll' is a straightforward rock symphony lasting about 19 minutes. Nothing wrong with that. If you like Comets On Fire, you can dig this too.
But b-side 'Jenseits' is the true discovery here: more than 20 minutes of seriously spaced-out ambient. At first it does remind of Tangerine Dream's first ambient works (think Zeit or Phaedra), but this is altogether more way out there among the stars. It even reminds a bit of Carl Craig's 'Neurotic Behavior'.
I would state that Inventions for Electric Guitar (also 1973) is even better, but then I wouldn't be telling the whole truth. Some of it is even better. The proto-ambient sounds of 'Quasar' are pure bliss. But both 'Pluralis' and opener 'Echo Waves' need a post-millennial edit, especially in those parts where Manuel actually starts thinking he is a guitar god, which is mostly toward the end, where, in the seventies, you somehow always needed to come to a bombastic conclusion. Nonetheless you can find some of the most beautiful sounds ever committed to record on Inventions.