From a 1994 Sound On Sound article:
Christoph Franke: “William Friedkin had heard our music in Los Angeles. He rang up and said he liked it, that it was innovative and new, and that he’d like to do a film with it. He was interested in having the music playing for the actors on set. We felt very independent — it was just us in a room in Berlin, with an 8-track and the script.”
Edgar Froese: “Sorcerer was recorded on an old 8-track Ampex in Berlin. It was one of the four machines that were in Abbey Road Studios in London, and which were sold after the Beatles era. We had rented an old movie theater in Berlin, and made a small studio out of it. The Moog was very useful, and by this stage we were quite versed in its use. We also used a Fender Rhodes piano, guitars, and even Revox tape machines as delay units”.
Image: “Grind” seven-inch.