The Mellotron (and Chamberlain)

If you imagine a mellotron to be a bank of tape machines, each with a short loop of tape in it, you will perhaps get the idea. If you play any one tape loop, it will play endlessly, because it is a loop. Each tape loop carries a different sound. One tape loop may have five violins playing a note E, with another having five violins playing the note G, and so on. When you press a particular key, you bring the tape's playback head in contact with the tape, thus you get that tape's sound whilever you press that key. Let the key go and the playback head moves away, and the sound ceases. 

The early electromechanical style of mellotron described above is now replaced by the all-electronic mellotron, where the musical instruments are digitally recorded for playback. This is more correctly called the chamberlain. It gets very confusing here between company names, such as Mellotron, and instrument descriptive nouns such as 'synthesiser', but all such machines became known generically as synthesizers. For a time, all synthesisers were commonly called Moogs, because Moog Electronics was the leading manufacturer in the field.. But not every synthesizer was made by Moog, so could not properly be called a Moog.

In a mellotron or chamberlain, the sound is not synthetic because it's taken from real instruments that have been recorded. In a chamberlain, the recording is digital (chip-based) instead of analogue (tape-based). It took some time to create the all-electronic mellotron/chamberlain because the world of electronics first needed to develop integrated circuitry, and because early electronic instruments could play only one digital sound channel at a time, not multi-stream them.

The Moody Blues' mellotron was played by Mike Pinder. At a time when those bands with a keyboard player struggled to make a simple organ sound decent, Mike Pinder was very creative and gifted with this machine. He could make it sound as if they had a whole orchestra playing with them, which was no easy feat with such a primitive device. King Crimson, an early rival to the Moody Blues, also used a mellotron, when Greg Lake was their lead singer/guitarist.

The mellotron was a heavy beast by modern standards and did not take kindly to being transported. Its circuitry was not properly speed-stabilised to make it independent of voltage fluctuations, so power supply variations in the middle of a concert would put the machine suddenly 'out of tune'. It was not robust enough for the rigours of a touring band and would break down frequently.

The Moody Blues' mellotron first featured on their seminal album Days Of Future Passed, which also had genuine orchestral passages recorded by Decca's London Festival Orchestra. When time came to record Seventh Sojourn, the mellotron was replaced by a chamberlain. When they broke up after recording the Seventh Sojourn album both devices were apparently retired and their rich sounds disappeared forever from The Moody Blues, despite Patrick Moraz (who later replaced Mike Pinder on the keyboard) being a one-time owner of a mellotron. The Moody Blues instead opted for simplistic organ sounds and abandoned the musically rich sounds they were so well known for. This was a surprise, given that groups such as Genesis and Emerson, Lake and Palmer were now producing wonderful music with synthesisers. The loss of the mellotron/chamberlain may help explain the ‘thin, under-developed sound’ of the Octave album. This, coupled with the near abandonment of close-harmony counter-melody singing, brought about a major change in sound to The Moody Blues. It may not be a coincidence that the mellotron came and went with what most fans today call the "Core Seven" albums.

The Moody Blues were not a success because they once used state-of-the-art equipment. A number of other groups used mellotrons, chamberlains and (later) Moog and other synthesizers, but only a few of those had any real chart success or received critical acclaim. The Moody Blues were a success because they sang soulful ballads of lasting lyrical and orchestral quality.