Combining 5U MOTM and Synthesizers.com modules in the same cabinet

5U is a standard 19-inch rack unit. The common 5U modules are exactly 8.75" (222.25mm), but non-American manufacturers may prefer 220mm or 230mm. 5U modules typically use 1/4" connectors and plugs for patching.

Dimensions
The height of 5U format synthesizer modules is 8.75", which is equal to five vertical units in a standard 19" equipment rack. (That's why the format is called "5U".)

The width of 5U modules varies. Some manufacturers use the width of the original Moog modules (1U = 2.125"), and as such, these fall into a sub-format called MU (for Moog Unit). MU module manufacturers include Synthesizers.com, Club Of The Knobs, Krisp1, Mos-lab, Moon Modular, STG Sound Lab, and ModuSonics. Other 5U manufacturers, like Synthesis Technology MOTM, Oakley Sound Systems and Modcan B-series, use a slightly narrower width, (a 2U wide panel is 3.485 inches wide). This is an important factor in mounting the modules. Since the module widths are different, the mounting holes are also in different positions. Thus, MU and 5U modules can't be mounted in the same row in racks that use metal pre-tapped holes.

Mounting Considerations
Here's some information on mixing MOTM-format modules, (which includes Modcan b series), into a Synthesizers.com cabinet. This section only discusses wooden cabinets - not racks. There are three main things to consider. First, how to physically mount the MOTM-format modules. Second, what number of each module-format can be fitted?. Third is power considerations, which is discussed above.

Height Issues
Synthesizers.com and MOTM-format modules are technically the same height. The real difference is the fact that Synthesizers.com-format modules have a lip at the top and bottom which MOTM doesn't. Here's a picture of the Synthesizers.com lip:



And here's a picture of a MOTM module showing that the module is straight with no lip at the top or bottom:



The mounting holes of MOTM-format modules are also placed at a slightly different vertical height to those on Synthesizer Dot Com modules. This means that if placing a MOTM-format module on the floor of a Synthesizer Dot Com cabinet its mounting holes will not reach the top rail completely. To counter this, make sure that any MOTM-format modules are centered in the rails before drilling mounting holes for them. The picture below shows in red the gap left in order to centre the module.



Actually mounting MOTM modules is fairly straighforward. The rails of Synthesizers.com cabinets are made of wood and can be easily drilled out for MOTM. The holes for MOTM do not interfere with the Synthesizers.com holes that are already present. Mark the holes making sure the module is centered as mentioned above. Drill the hole with a 1mm or 2mm bit. Then screw in one of the mounting screws to "tap" the hole before mounting the module. The MOTM mounting holes will be closer to the edge of the rails than the Synthesizers.com ones. The picture below has MOTM holes marked in green and Synthesizers.com in red:



Here's a picture of the two formats together (don't worry about the gap here - The modules pulled to take the mounting hole photos hadn't been replaced yet.)



Width Issues
To consider how many of each module fit in the case, the widths of single space modules are as follows:
 * 1U Synthesizers.com = 2.125 inches
 * 1U MOTM = 1.75 inches

22-space Synthesizers.com cabinets have rails that are 46.75 inches wide.

The table below shows all the combinations of Synthesizers.com format modules and MOTM-format modules you can have in a 22-space Synthesizers.com row. Specifically, it shows:
 * number of single space Synthesizers.com format modules
 * resulting space remaining (in inches) in cabinet
 * number of (whole) MOTM format units available
 * the gap (in inches) that will remain when the case is full

Some combinations work better than others. Eight Synthesizers.com format and seventeen MOTM-format spaces is the magic combination where there are no gap at all. Note that this table will only work if all the MOTM-format modules are mounted in a block together and the Synthesizers.com modules together. Putting them in-between each other would, if you used the pre-drilled Synthesizers.com mounting holes, mean more gaps. Different Synthesizers.com mounting holes can be drilled in the relevant place(s) to leave the smallest possible gap.

Power Requirements
All modules from the 5U manufacturers need a +/- 15v power supply. Frac Rack modules and Wiard 300 series also use +/- 15v. Some 5U manufacturers also need a 5v source, specifically Synthesizers.com and some of the newer MOTM modules from Synthesis Technology, e.g. the MOTM-650.

Most 5U manufacturers sell suitable power supplies:
 * Synthesizers.com sells +/-15v and 5v supplies
 * MOTM Synthesis Technology sells 2 supplies, one with only +/-15v (MOTM 900) and one which also has 5v (MOTM 950)
 * Cyndustries sells +/- 15v supplies
 * Modcan sells +/- 15v supplies

If using one manufacturer's format then the easiest thing to do is to stick with their power supply and distribution system. Here’s what each uses:

Synthesizers.com
Synthesizers.com use a 6 pin connector to get power from the power supply to modules.



Power is distributed from the power supply via a power harness which contains a number of these connectors. They sell 2 models: the small power harness has 20, the large has 40.



MOTM Synthesis Technology
MOTM use a 4 pin connector on most modules – those that only need +/- 15v. These are the same power connectors that Frac and Wiard 300 series module use. Some of the newer modules, that also require 5v, use the same type of connector but with 6 pins (not the same one as Synthesizers.com use)



Power is distributed from the power supply via power distribution boards. There are two main versions – one with only 4 pin connections (i.e. +/- 15v only) and one with a mix of 4 and 6 pin connectors (providing +/-15v and 5v)





Modcan & Cyndustries
Modcan and Cyndustries have the same type of connector as MOTM to distribute power to modules except they only use a 3 pin version which provides +/-15v only.



Power is distributed from the power supply via a distribution board. The Modcan one (which is completely compatible with Cyndustries modules) looks like this:



But wait – I’ve got more than one 5U format! Now it gets interesting. There is no one way to distribute power to a mix of 5U formats. Here are some off the shelf solutions:

Synthesizers.com & MOTM Synthesis Technology
If only want to add one or two Synthesizers.com or MOTM format modules to a system mainly of the other format then Synthesizers.com sell their QMPSA adaptor which convert between the two formats. This adaptor also provides a 5v source so Synthesizers.com modules can be run off a MOTM +/-15v power supply.



For more than a couple of modules this probably isn’t the most cost effective solution though. For more modules it’s easier to use one of MOTM’s convertor boards – MOTM 995. This gives a combination of 6 pin Synthesizers.com, 4 pin and 6 pin MOTM connectors and can be connected to either a Synthesizers.com or MOTM +/- 15v and 5v power source.



The other option is to use a Synthesizers.com power supply with a power harness to connect to the Synthesizers.com modules. Strip one of the 6 pin connectors off the power harness and, using the colour-coded wiring guide on the Synthesizers.com site, wire the harness directly to one of the two main MOTM power distribution boards that are pictured above – they have binding posts that make this easy to do. If the 5v is not required for MOTM modules simply snip this wire short on the Synthesizers.com harness and tape it up.

Modcan & Cyndustries
Adding Modcan and/or Cyndustries is a relatively straightforward task and in many ways similar to connecting Synthesizers.com and MOTM together. The only difference is that Modcan/Cyndustries use 3 pin, rather than MOTM’s 4 pin connectors.

With Modcan probably the easiest option is to ask Bruce to terminate the power cables in MOTM style 4 pin connectors – he’s fine with doing this. Then use exactly the same type of distribution system used with a MOTM or MOTM/Synthesizers.com mix system. Remember Modcan are +/-15v only – no need to worry about 5v for them. This would also work for Cyndustries modules although I have no idea if it’s something Cynthia will do or not – can’t hurt to ask I guess!

The other option would be to use a Cyndustries power distribution board, which provides connectors for 4 pin MOTM and 3 pin Modcan/Cyndustries. This could be wired to a suitable power supply using binding posts as with the MOTM distribution boards.



STG Soundlabs Distro Board
A further option is the distribution board made by Suit and Tie Guy. These can be ordered with a combination of Synthesizers.com, MOTM and Modcan/Cyndustries connectors. They have a set of screw terminals for attaching the power supply. Details can be found from the page in the links section below. STG can also provide suitable cables for powering Synthesizers.com modules from this distribution board. Here's a picture of one (which is now residing in my cabinet )



Power supplies

 * Modcan power information
 * MOTM Synthesis Technology power supply
 * MOTM Synthesis Technology power distribution boards
 * MOTM Synthesis Technology power distribution boards
 * MOTM Synthesis Technology to Synthesizers.com adaptor board
 * Synthesizers.com power components
 * Synthesizers.com power wiring information
 * STG Soundlabs distribution board
 * STG Soundlabs power cable