This is a project I started in 2017 and finished at the end of 2018. I wanted to build my own synthesizer from scratch and this MFOS ( by Ray Wilson) project was perfect.

I had the option to expand the synthesizer by adding the Ultimate Expander next to the main synthesizer, but instead I designed a unified aluminium case to house both those devices. Of course I had to design everything from scratch, if you are interested to know how, you will find all the info below.

Interface/Metal Casing

For the interface I designed a unified Ultimate + Expander panel where all the “modules” are in a more familiar order, first the VCOs, next the two VCFs, next the Envelopes etc, and I moved all the patch points to the right of the panel, in a unified patch bay.

The metal casing was designed by myself and my good friend Ioannis Perisoratis from πlab / creativeCoding in AutoCAD. We then ordered the panel from a machine-shop and it came out great! We used 2mm thick aluminium.Then using a sanding machine I smoothed out the interface to make it easier to apply the sticker.

I designed the UI in Illustrator. I printed the file in transparent vinyl sticker and applied it to the metal panel with the help of my good friends Ioannis Perisoratis and John Moras. They also helped me cut the holes with a razor so the panel components can go through the panel. We also applied 3 coatings of matte clear varnish on top of the sticker to make it more durable and give it this matte finish.

Colorwise I used black, white, red and a few shades of grey. Along with the led colours (red + yellow) and the wood side panels I think it came out great.

The wood side panels are just plain wood that I cut in shape, sanded and used a technique I saw on youtube using tea, vinegar and steel wool to give it this kind of “aged” look.

MFOS Drill holes
MFOS Panel Design

Patch Bay

For the patch bay I used 3.5mm Jack through hole sockets instead of banana sockets to make it easier to communicate with other (semi)/modular stuff. I labeled all the outputs with reverse colouring to make it easier to intentify the ins and outs. The different sections are separated with lines.


For the LFOs I changed the original, rather odd wave selection combination and instead I used 2 pole 4 position rotary switches instead. The only problem is I accidentally labeled the waves in reverse so I had to order 2 small stickers and replace the false labelling on the panel.


I absolutely wanted the synth to have MIDI input to make it easier to control it. I searched a lot and in the end I bought a DIY MIDI to CV from Erica Synths ( … idi-cv-ii/ ). I ordered the basic version, just the pcbs and ICs and incorporated the leds, jacks, switches and potentiometer to my synth panel. The module works great and it can also make the synth duophonic.



For the PSU I used the MFOS wall wart power supply with an EHX 12v AC-AC 1200 power adaptor. The PSU provides enough power to supply the Ultimate, Expander and MIDI to CV module. Since the metal panel is grounded I used a plastic 3.5mm jack socket and a 3.5mm jack male (I modified the EHX power adaptors plug) to connect the adaptor to the panel.

LFO wave selection w-01
MFOS Panel Design sections