 Having only recently returned to producing , after the commercial failure of Ike & Tina Turner 's 1966 single " River Deep – Mountain High " in America , Spector had " passed the audition " , according to Beatles Forever author Nicholas Schaffner . " Instant Karma ! " was the first of many Beatles @-@ related recordings that Spector worked on during the early 1970s , starting with the band 's final album release , Let It Be ( 1970 ) . 
