Spectra 1964 is the same company as Spectra Sonics that built the desks in many studios, including Muscle Shoals, Ardent, Stax, Advision, Chateau d’Herouville and the Record Plant studios.
Their 101 preamp was the soul of these desks, and many famous albums were done on them including T. Rex’s Electric Warrior, Aerosmith’s Toys in the Attic and Get Your Wings, Led Zeppelin’s III, Elton John’s Honky Chateau and Don’t Shoot Me I’m Only the Piano Player, Big Star’s #1 Record, most of the albums Tom Dowd recorded, all the Stax and Muscle Shoals output from the mid-sixties onwards, and more.