The Mellotron was an innovative tape-based keyboard instrument which became a trademark sound of ’70s progressive rock bands. Under each key is an 8 second length of magnetic tape which is moved past a playback head whenever the key is pressed. When the key is released, the tape is pulled back to its starting position by a spring. Since each sound is produced by a linear piece of tape rather than an endless loop, the Mellotron can reproduce the characteristic attack phase of an instrument such as a violin. Early Mellotrons had long tapes divided into six separate sections, each with three tracks, which could select different sounds. Motor driven rollers shuttled the tapes back and forth to select one of these six stations. The Mellotron Mark II had two keyboards of 35 notes each for a total of 1260 separate recordings inside the box! The Mellotron was based on an earlier instrument, the Chamberlin, invented by Harry Chamberlin in 1948.