i'll try to hew to your particular definition of "psych," though you're going to make me lop off Gong, "Anthem of the Sun," and a lot of other pivotal shit:
the first Ash Ra Tempel album. when i turned a friend onto this record he commented "i should have listened to this record when i sniffed glue." seriously, it's like sticking your head in a vacuum cleaner, in a good way.
Acid Mothers Temple. for that matter, we can cover Gong as well: get the DVD of the Acid Mothers Gong performance from Amsterdam 2006, which i attended and which was one of the most remarkable things i've ever seen. Kawabata will make your brain explode. promise.
i didn't start from "A," honest.
for gnarly guitar sounds, you really should check the mid-1970s Hot Tuna albums, "America's Choice" and "Yellow Fever" which are not only replete with nasty fuzzes and octave dividers, but with same deployed by Jorma Kaukonen and Jack Casady. it's like a jug band being run over by an enormous Orange amplifier. whee!
"Neu! 75" was gnarly enough to inspire PiL and Warsaw, latterly Joy Division. and as long as we're on the gnarly Krautrock vibe, there's always "Phallus Dei" and "Yeti" by Amon Duul II; i prefer "Yeti" for its utterly deranged Jefferson Airplane-goes-to-Bulgaria compositions but "Phallus Dei" has its own grungy sub-"Tago Mago" charm.
and if you're listening to psychedelic music and you don't have a copy of "Happy Trails" by Quicksilver Messenger Service, you're in the equivalent position to someone listening to modern jazz without a copy of "Kind of Blue." half the psychedelic guitar players in Japan are biting John Cippolina's style here
to the bone; John is likely the most under-recognized guitarist in rock history nowadays.