5U Modular Synthesizer Format

Moving MOTM-pots is not only a great pleasure, but also more differentiated than is possible with the small Eurorack pots. The coordinated appearance creates a more coherent feeling with me - somehow a greater calm.

The high-quality basic data of this 5U format were defined by the users and developers, and these requirements also affected components. The format is not tied to a company. The solid controls and switches, as well as the whole appearance, are visible and tangible. Due to the fixed positioning of the controllers and I/O's, this format does not look as exhausting as the Eurorack format. The patch cables have 1/4 'jack (6.3mm), the control voltage is 10V pp the most common and thus also most compatible. The operating voltage is 15V.

The circuits come from all directions: Moog, Roland, ARP, Yamaha, Buchla and custom developmets - a kind of a box of chocolates. The MOTM 300 VCO - a development by Paul Schreiber (Synthtech) - is undoubtedly one of the best oscillators ever to buy. The 4014 Ring Modulators (ARP circuit) from Oakley Sound are outstanding - probably the best I know!

Some modules are equipped with less CV-I/O's to keep the size in check, but there is often a more complex/larger version of the same module with (more) I/O's. The MOTM format seems to be more knob-driven than designed for remote control - while playing, you'll notice that fast (in terms of quality and feel).

Extreme interconnections are more likely to belong to the "Westcoast" area (especially Serge) - but there are also Westcoast modules in MOTM. Most of the MOTM users, however, enjoy the manual bending of the sounds with a clear East-Cost tendency. On the other hand - some Eurorack modules have just been converted to MOTM - I especially noticed the covertions of the digital "Mutable Instruments". Many "cult" modules, regardless of format, can be found in MOTM.


What to look for

Statements about the construction quality of the modules are not to be made generally, because in a DIY format no uniform production control takes place. For my four "used" modules, which I had purchased (from 3 sellers) on eBay, I have consistently had bad experiences: bad (cheap) components were still the smallest evil. The selection of the module builder is therefore crucial and one should necessarily inquire before.

The best - one must say: the most impressive - quality I found in the modules, which Paul Schreiber has built - but the sale (and I assume, also the production) has now forwarded and (seemingly) concentrated more on the Eurorack. As good as the modules are - and they are true masterpieces - the waiting times were exorbitant and never corresponded - by far not - to the previously made arrangements. This was really no pleasure. So maybe it was not the worst idea to sell. Nevertheless: the modules of Paul Schreiber are impressive! The manufacturing accuracy reaches the "Military Grade". Even after seven years, all work as on the first day.

My modules from Oakley Sound were all built by Paul Darlow (Krisp1). Not only the greater proximity (UK instead of USA) - the business procedure was much more relaxed and better organized. There were never any reasons for complaint - quite the opposite. I have to say, however, that some modules (Pots) after 4 years no longer worked properly and made a service necessary. This should be due to the components (I'm not a technician).

As it is now with the trade - especially with the Synthtech modules - I can not judge - my last 5U module purchases have already been more than 5 years ago. Overall, the MOTM format is more on a side-way and in the 5U world it has changed. The MU format, I believe, is currently the most widely used 5U format and offers a similar module selection. I can not say anything about quality or differences to MOTM because I've never worked with MU. It was and is represented by sovereign, but there are MU modules from Oakley Sound as well. There are also new 5U companies like Club-of-the-Knobs, Moon-Modular, Marienberg and more. I am not up to date and am happy with my MOTM modules. The Club-of-the-Knobs (from Lisbon) is worth a look!

    My MOTM Synth

    The MOTM modules I use are from Synthtech - the (last) home of MOTM in the US - and from Oakley Sound Systems, the UK's leading provider of this format.

    Synthesis Technology:

    120 Sub-Octave Multiplexer
    300 Ultra VCO (3x)
    310 µVCO
    320 VC LFO (2x)
    410 Triple Resonance Filter
    440 Discrete OTA LowPass Filter
    510 Wave Warper
    700 Dual VC-Router
    850 Larry Hendry Prototype #1 Dual Exp.-Pedal
    910 Multiples

    Oakley Sound Systems:

    Oakley VCO
    Noise and Dual Filter
    Diode Superladder-Filter
    Triple Lag
    4014 Ring Modulator (2x)
    MultMixer (2x)
    ADSR/VCA (2x)
    Triple VCA (2x)
    Envelope Follower/Gate Extractor
    Comparator & Gate Delay
    Equinoxe Phaser

    I started with MOTM in 2010 and received the first row of modules from Jürgen Haible, a syntho-phile genius that passed away too early.

    I enjoy my MOTM synth extraordinarily. Unfortunately, the MOTM format has been declared to end in 2018.


    A power supply alternative

    MOTM had irritated me from the beginning with the somewhat fragile situation and the OEM power supplies offered by Synthtech and Oakley, since they are not very powerful, but rather large (3U) by positioning on the front and also not exactly cheap. Through a matrix development, I was lucky enough to team up with Graham Hinton of Hinton Instruments, who had proposed to build new power supplies for me.

    The Hinton power supplies have a ring core transformer, are excellently constructed, CE-tested and perfectly matched to the requirements by precise agreement.

    In the big case I attached the power supply along, on the side. So it is invisible and the whole front surface is available for modules. Also in the second case the power supply is not on the front, but it is attached to the back wall. This PSU is also for the Matrix and therefore supplies +5V additional to the ±15V. The Hinton power supplies are designed and built extremely carefully!

    With the power supply change, I have also exchanged the power connection cables and the distribution cards: now Molex- instead of MTA-connectors are used. On the distribution card of the second case are also 6 Eurorack connections.

    The EuroRack modules in this case are fed with 15V instead of 12V. Such a thing can not be done with all Eurorack modules - and must be clarified beforehand.

    Case I

    19 Inch Cases
    • Especially with the heavy 5HE MOTM modules a good case is important for transportation. A wooden case is more beautiful, but hardly transportable. I had decided for 19 inch plastic cases (!). To keep the cases as flat as possible, I had chosen 14cm depth - and therfor excluded some modules for this case. To transport the instrument patched, the lid must be 8 cm deep. My 15 HE Case has an outer dimension of 53 x 23 x 70cm.

      A comment on the case feet: (with the removed lid) make sure that all four feet are on the underside of the case. For transportation two feet must be placed on the lid and two on the case (longitudinal side) - my case is therefore an octopod.

      19 inch are 10U MOTM. I chose 10U for the lower and 15U for the upper case. The cases have 14cm depth enough space for many, but not for all offered MOTM modules. Especially the CGS (Cat Girl Synth) modules sometimes want 20cm and more.

      For optimal positioning and as protection against falling over, the cases can be fixed on the stand of Ultimate. The stand is a little modified. For the upper case, I attached a Vesa monitor mount to the stand and case to prevent slipping. The crossbars are shortened to about 12cm.

      Case II

      Cabinet: more instrument than equipment
    • I put it off for 10 years - and it was a mistake! I finally built a cabinet for my MOTM modules. The modules were simply too big for transport (e.g. for the train), too heavy, and since I have had the Buchla 200 modules (which are very light), the MOTM has not been on the road for 5 years. As a supplement to the Buchla, 8-10 MOTM-U are enough - 10 MOTM-U fit in a small 5U 19 inch case. For this I have an extra external power supply and the 4 - 6 (changing) modules can easily be temporarily exchanged. What was immediately clear, however, is that the shape of an instrument is also part of the interface. I really suffered from the 19 cases!

      As usual, I worked without plans. First I arranged the modules so that I could determine the height and width of the required rectangles for the side parts.

      Floor, back wall and ceiling are glued to the side parts, which is why they all have the same width - which is good if you shop in the hardware store because the band saw is only adjusted once and all parts are exactly the same (which you cannot do by hand).

      The necessary investments are kept under € 80 in a very clear framework (wood, glue, sandpaper, pickling powder, worktop oil). I did the work in 4 days. Watering and sanding in particular takes some time (several passes) if the surface is to be really smooth.



      A worth mentioning is the high weight of the cables on a patched synth (Case). At first I underestimated this. The patch cables of the MOTM weigh more than 8kg - almost as much as the 84TE Eurorack wooden case with a power supply, modules and patch cables!

      The cost of components for self-assembly (for example, of Neutrik and Sommer) is about €7.- for a cable. I have patchwires from PlanetWaves for the short connections that I like very much because of their bantam-like, narrow plug and the lifelong warranty - I got them luckily - they would have been much too expensive for me to buy new. offer very nice cables, over which I have already heard a lot of good. They are amazingly cheap, but postage and VAT made the price broken.

      In order to have the cables ready for hand, I have converted a tripod of the drumset into a cable harness. For this I bought three VOLTCRAFT ML-1 SW (for 6,3m Jack) and erased the logos. The brackets are attached to an aluminum profile with a total of 6 screws. A simple and perfect solution for me.

      cables @