Mellotron M4000D

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Behold, the mighty Mellotron. Like its predecessor the Chamberlin, it used racks of tape containing recordings of real instrument sounds, and can fairly be thought of as the original “sampler.” It became part of the pop music landscape in the 1960s and part of the progressive rock movement in the 1970s. It faded into legend as more portable and reliable technology such as digital samplers came to the fore, but there’s something about it that has kept us coming back. While its iconic sounds have found their way into modern synth workstations and software, the M4000D represents the ultimate expression of the classic Mellotron playing experience using digital technology.

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Wood and Metal

From a birds-eye view, the M4000D resembles the classic M400 and current Mk. VI (a modern tape-based Mellotron): Its white wooden case (other finishes can be ordered) houses a 37-note keyboard, controls to the right of the keys, and flat top that can support an additional small keyboard or other gear. Unlike its elders, the M4000D is only 5.25 inches tall and weighs 33 pounds. The lid opens to reveal the same wooden key action as in the Mk VI. The keyboard is a joy to play, and is lighter and faster than the old 400’s more resistant action. It’s refreshing to see a modern digital instrument that employs wood and metal the way the M4000D does—there’s no denying its high-end stage presence.


The M4000D comes with 100 sounds drawn from various Mellotrons and Chamberlins. It’s bi-timbral, and there are always two active sound slots, A and B, with sounds loaded and ready to play. By turning Select A or Select B you immediately get access to any internal sounds or the 100 sounds on an inserted expansion card. In spite of their high quality (which suggests large sample sizes), sounds have no load lag. Each slot has its own screen, displaying a graphic of the particular instrument from whose library the sound originated (click image at right to enlarge). The Mix knob blends the two slots.

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Press the Select B knob for a convenient list view of the presets, and press it again to enter a custom playlist mode to assign and access user-definable favorites. The presets include Melltron classics like strings, woodwinds, lesser-used standouts like vibraphone (a personal favorite of mine), brass, mandolin, and other keyboards and percussion. You won’t find the rhythm and accompaniment tracks that were in some of the original Mellotrons, but they, along with lead sounds, will be part of the first available sound expansion, a custom Compact Flash card.

The sounds are impeccably reproduced from the original tapes at 24-bit resolution, with one sample per key and, like the original, have a duration of about eight seconds with no loops. The M4000D’s sounds remain sustained if you change presets while holding keys, which is great for live performance. You can opt for some velocity sensitivity to volume, and also bring in more volume via polyphonic aftertouch. A high-low toggle in the middle of the panel drops the sound an octave. Another nifty feature is that you can choose subtle EQ characters for the instrument globally: a cleaner, clearer output with “Chamberlin M1” or a slightly muted vintage character with “Worn Tapes” (Mellotron M400). The sounds by default had a bit of a longer decay, but I was able to quickly change that setting to the more ’Tron-like (and organ-like) instant stoppage of sound once I released a key. You can also define the “tape rewind time,” which will make ’Tron fans happy. Don’t go looking for reverb or multi-effects here, though. It’s not that kind of instrument.

Audio and MIDI

Audio is handled by the same analog volume and tone control pots found in a Mellotron Mk. VI if you use the master output. These controls are bypassed when using the A and B direct outs (click image at left to enlarge). There’s no stereo unless you pan the A and B outs using an external mixer, but tape-based Mellotrons are monaural as well. The volume pedal jack is meant for an audio volume pedal such as an Ernie Ball Jr.—plug the TRS end of a send-and-return Y cable into it, then the forks of the Y into the pedal’s input and output.

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The sustain pedal input can be assigned to “Release Time” (the 4000D’s version of sustain), or to step incrementally through “playlists,” which are pairs of sounds you can choose for quick access. Then there are are two “Expr” (expression) pedal inputs. Expr 1 can control the A/B tone mix using a standard MIDI expression pedal. Both can also accept switch pedals to increment or decrement through playlist entries, if you modify the pedal by rewiring it to a TRS plug. This is both cool and uncool; it’s nice to unlock more functionality in the instrument, but who’s got time to solder? Sustain pedals from other manufacturers that support half-dampering (and therefore have TRS connectors) won’t work in this application, so Mellotron may make properly modified pedals available for sale in the future.

The keyboard transmits polyphonic aftertouch as well as the more common “channel” aftertouch (you can choose which, or choose not to send aftertouch) and you can assign the Expr inputs to control parameters such as volume sensitivity to velocity and aftertouch. I did experience some stuck notes when using a sustain pedal and coarse resolution when using expression pedals. Consulting with M4000D creator Markus Resch, we troubleshot this to a specific MIDI malfunction on my review unit and verified that units in his possession were working properly.


At a time when instruments constantly leapfrog one another in terms of features for the buck, it’s easy to overlook the courage it takes to produce a keyboard like the M4000D. I once lived with a vintage Mellotron M400, and as joyous as it was to play, there were plenty of times where inspiration took a hike before I finished changing tape racks. The M4000D captures much of the joy with nearly none of the maintenance, and it practically makes a game out of blending its character-rich sounds. Every time I’ve played it, it inspired composition.

For some, the price will surely be an issue. It’s not cheap, but it’s as fairly priced as you can expect any high-end, limited quantity, handmade-by-a-guy-in-Sweden instrument to be, and it’s a downright bargain when compared to what a new (or well maintained vintage) tape-based Mellotron would cost. You can save a few hundred bucks by opting for the Mini model, which employs a semi-weighted Fatar action without aftertouch, has 1/4" outputs only (not XLR), and is built in a slimmer case. The M4000D is an inspiring realization of a beloved classic that adds modern conveniences while retaining the old-school magic.

PROS: Handmade boutique quality. Real wooden Mellotron key action. Gorgeous 24-bit samples of classic sounds. Polyphonic aftertouch. Expandable. Instant layering of any two sounds.

CONS: Handmade boutique price. Modified foot controllers required for some control features.

Bottom Line: To get the authentic Mellotron experience with minimal hassle, the M4000D is the definitive realization of the dream.

M4000D: $2,800 | M4000D Mini: $2,000 | Sound expansion: $500