 The Mellotron became more popular after the Beatles used it on several tracks . It was subsequently adopted by the Moody Blues , Genesis and King Crimson , and became a notable instrument in progressive rock . Later models such as the M400 , the best selling model , dispensed with the accompaniments and some sound selection controls in order to be used by touring musicians . The instrument became less popular in the 1980s due to the introduction of polyphonic synthesizers and samplers , despite a number of high profile uses from Orchestral Manoeuvres in the Dark and XTC . 
