As with many of my creations this all started with a simple sketch on a long lost page in one of my notebooks. Why are modular systems always arranged in a linear fashion, why not change it from a line to a plane? After a quick 3d sketch it showed some potential but as with so many things, life has a way of changing your plans so this project got shelved for a couple of years. During those years I honed my electronics and design skills for various clients and personal projects as a visual artist. But the idea never really went away and I kept on sketching and refining the original concept.
At the start of 2020, that all changed. The thing that shall not be named happened and I suddenly found myself with just the right amount of time and commitment to continue working on the modular synth concept. From the start I had a couple of very clear goals in mind. I wanted it to be scalable, cheap(ish) and very reliable. I decided to ditch the regular linear format like the ever ubiquitous eurorack and MOTM systems and opted for a grid approach. After testing various prototypes I decided on a 50x50mm grid, a good compromise between usability, space and cost of manufacturing.
The first version was made from some left over sheet metal which was painstakingly drilled with the 81 holes and fitted with M3 standoffs. It was quite tricky to accurately drill all the holes but with a little gentle persuasion it all went together nicely. The system was intuitive to use and the spacing of the first few modules felt very comfortable to use. The flexibility of the grid system allows you to group certain modules in a very organic way.
Meanwhile I kept on working on more modules and experimenting with functionality of the system. A lot of time was spent to testing the various controls and spacing. Slowly but surely I narrowed down important parts like the power delivery system and mounting hole spacing till I had a solid base to work from for the next prototype.
With the lessons learned from the first prototype I went back to the drawing board for a second prototype. This time I designed it as a single piece of 2mm laser cut and machine bend aluminium. The accuracy of the laser cut holes solved the problems I had with alignment in the first prototype and made the whole assembly process a lot more streamlined. The size, stiffness and looks were exactly what I wanted and it feels about the right size. Enough space for a good selection of modules without being too cumbersome.
The second prototype also featured a lot of improvements for the power supply and cable management. The patterned slots make cable management a breeze. The circular power distribution boards have individual fuses on each power line so when a module draws too much current it only affects that quarter. They are spaced so you can reach any module around them with the same 150mm cable, simplifying the process of switching out modules. The board at the bottom was the first attempt at integrating a power supply. It uses off the shelf Meanwell modules and also includes the main audio output amplifier.
The second prototype was getting closer but I didn’t really like the quite bulky power supply and the use of off the shelf modules. And although I couldn’t measure any noticeable noise the fact that the power supply and analog output board were combined didn’t sit right with me. So I kept the basic mechanical construction and redesigned the power supply to be a fully custom low noise switch mode supply which uses a 36W USB PD adapter. I really dislike separate power bricks and USB C is finally becoming more ubiquitous and it’s a perfect fit for this application. For the audio output I designed a much simpler board which just routes the audio directly from any module supporting audio output(mixer, amp, etc.) over a shielded JST XH 3 pin cable. In the future I also plan on designing a headphone amplifier and a USB audio interface.
From the beginning I knew the base would be the most important part for this system to function and I hope this write up gives some insight into the work that went into designing the final version. It has been a long process but the lessons learned along the way were invaluable to end up with the perfect base for the mosaic system. And as with everything mosaic, there is nothing stopping you from designing your own and sharing it with the community.
MM base 8×8
