DIY Portable Modular Case

Necessities

Before getting into building any functional modules, it is obvious that I first needed a functional modular case. Then I had to start with a first question:

How do I want my modular case to be?

Firstly, I needed it to be big enough so I wouldn’t outgrow it very fast, but also not too big, since I didn’t have much space available at home. I saw a very standard size to start with was around 88HP in width and 6U in height. Again, I wanted to make sure I wouldn´t run out of space too soon so I decided to go for a bit more and settled down with 104HP and 6U. This makes a total of 208HP to be used.

Secondly, I wasn’t planning to keep the modular system in a specific space (again I didn’t have much space available), and I wanted to be able to take it around to play it with friends and family. Therefore it should also be a portable case.

Finally, I wanted to keep it all together and tidy. Being a portable case, I should also carry around patch cables, the power cable and maybe some more small accessories. I decided I wanted the case to have a small storage space where I could keep everything together.

What material?

The case had already quite defined dimensions, and I struggled to find a premade box that fitted the requirements. This encouraged me to build the whole case on my own. For that aim, it made most sense to make it out of plywood, since it’s a relatively cheap and accessible material.

What about power?

Again to save as much space as possible for modules, I wanted a power source integrated in the case, and powerful enough to feed the two rows of modules. I also did not want to build the powersource myself. I didn’t feel comfortable dealing with mains voltage and I didn’t have enough experience (yet) to decide on the components to make it powerful enough.

Therefore, I decided to go for a commercial power source. I knew I was going to use arduino for some modules, so I needed it to have a 5V supply to make things simpler. After comparing some available options at that time (spring 2022) I decided to go for Modular Synth Lab “Eurorack Power KIT, Modular Synth Power KIT 1, MW RT65B”. This included a power socket and a bus board that has 20 modular sockets. To make sure these 20 sockets would be enough for my case size, I went to modulargrid.net and had a look at several cases with 104HP 6U, finding that the average number of modules was around 20. I thought it should be fine, and if not there’s always time to expand.

This power source had the following specifications:

• PSU rated power: 64.6W

• 12V DC / 2800mA – 3500mA

• -12V DC / 500mA – 1000mA

• 5V DC / 5000mA – 8000mA

Which seemed like it should be more than enough. We will see, my plan is to make measurements of roughly the power consumption that will be required for every module I make.

Design

According to the needs described and available materials, I made the following design:

The box would have a removable lid using removable hinges, and would have a briefcase like design.

For assembling the box, I learned some basic woodworking techniques, and decided to use finger joints for the sides and a couple of dovetail joints for attaching the top and bottom panels. The outer panels were made of 1 cm thick plywood.

On the inside I used the purchased rails and power supply, but I needed to build up the storage space, for which I used 5 mm thick plywood. Also, to structure the rails I made a couple of aluminum ears from 1 mm thick aluminum.

Finally, based on some examples I had seen online (I remember one advertised by Andrew Huang), I designed a patch cable holder. The holder must fit inside the storage space so I can keep patch cables tidy and bring them around, but it should also be removable to put it somewhere more comfortable. Also made out of 5 mm thick plywood.

Result