After the imposing and very heavy Mark II, the lighter but still voluminous M300, the M400 was the first Mellotron whose size and weight allowed it to be carried easily.
The M400 is the most famous and the most widespread of the Mellotrons.
The M400 used 3/8" tapes and had one single 35 note keyboard (G to F). It didn't have a rhythm or an accompaniment section anymore, but only solo sounds.
The first M400s had a CMC-10 control card. This card needed a warm up period before the Mellotron could be used to its full effect. Moreover, 6 or 7 notes played at once made the motor slow down, which caused a drop in tuning.
The M400s built from 1973 / 1974 had a SMS-2, which was much more reliable.
The controls were quite simple : Volume, Tone , Pitch Control, an On / Off switch, and a track selector. An input for a volume pedal was available in the front of the instrument. At the rear, it had a unbalanced 1/4 inch audio output, and on the most recent models (from 1973 / 1974), an balanced XLR output.
The Mellotron M400 exists in three versions : the most widespread has an aluminium sheet ; a rarer version, commercialized by Mellotronics in London, had a black sheet and a third version, commercialized by Sound Sales Inc. in USA (from 1977) had a black sheet with textecolor knobs.
The Mellotron M400 and the Novatron 400 are the same machine ; only the name is different (see A Mellotron history).
M400 Mellotrons had a cabinet made of white polished wood. Novatrons 400 were available in black or white.
The way the M400 worked was much simpler than on previous models : the banks with multiple sounds that could be found on Mark II and M300 had been given up and replaced by a removable 35 tape frame. No more rewind between each bank change - which was a delicate operation for the tapes. A frame was the equivalent of a bank with 3 sounds ; thus, to change a bank, you only had to replace the frame by another frame. Each additional frame was supplied with a flightcase.
Thanks to this removable frame system, a wider range of sounds was available. When you ordered an additional frame, you only had to choose your 3 sounds among those that were available. With the M400, new sounds appeared. The choirs, which have now acquired a mythical status, are one of those new sounds.
You could also bring Mellotronics your own sounds, and they converted them to 3/8" format ; this way, you had a personalized sound frame. Steve Hackett recorded his own voice, Paul McCartney recorded bagpipes from the Mull island, as well as various sound effects.
A conversion kit, including tape guides in standard 1/4" format, was (and still is) available. With this kit, you could record your tapes with a standard 2 track tape recorder, and use them with your Mellotron afterwards.
Each Mellotron was supplied with a volume pedal and a transport cover : the Protecta Muff.
Having bought a license from Streetly Electronics, EMI built a hundred M400s. Streetly supplied the Mellotrons in spare parts, EMI assembled them. The cabinet of these models was in polished wood and their serial number began with E4. They were very badly assembled, and almost every one of them has been sent back to Streetly to be assembled again.
A left-handed model has been especially made for Paul McCartney ; the controls are on the right side of the keyboard.
A Mellotron M400 FX was also available. It was supplied with 12 tape frames including 105 sound effects each.
A M400 with a Plexiglas cabinet was created by Mellotronics for the London Music Expo in 1972. With this see-through Mellotron, you could see the internal mechanism and the way it worked. Now this model belongs to David Kean (Mellotron Archives). A second model of this kind was built by Sound Sales in 1977.
A "portable" version of the Novatron 400, called T550, was built between 1981 and 1983. Only 3 were made. It was a Novatron 400 in a flightcase, with additional storage place for 2 tape frames and a volume pedal.
Dimensions (cm) W x H x D : 70.5 x 88 x 66 - Original price : £999.