A modular synthesizer in Kosmo format, in two cases, one with two rows of modules and one with three; each row is about 75 cm wide and 20 cm high

Kosmodrome, January 2024

Kosmodrome is a modular synthesizer I started building in 2020. It’s a Kosmo format synthesizer; there’s more about Kosmo format here .


Kosmodrome is housed (for now…) in two cases, each about 77 cm wide. They are made from nominal 1 by x dimensional select pine. I like the look of that better than plywood, and I designed around standard board widths so there was less cutting involved. Both cases are stained with cherry stain (two different brands, though, so they don’t really match).

Rails are Vector TS600 extruded aluminum, with M2.5 slide nuts. Vector is about the cheapest aluminum rail around, if you buy it as a package of four nominally 60" rails. (Actually about 61". Cut in half, that makes four rows each about 77 cm wide. Which explains the case width.) Unfortunately it does not accommodate M3 slide nuts (HP threaded strips aren’t suited to metric width Kosmo modules), and M2.5 slide nuts are hard to come by, but Pulp Logic sells them.

The first case contains a Frequency Central FC power supply and two Analog Output Power Supplies , each of which provides power to a single row via an Analog Output Bus Board . These get their 12 VAC from a pair of Jameco wall warts, connected via barrel jacks and toggle switches on the back of the case.

The second case is entirely powered by a Bel Power Solutions HBB15-1.5-AG power supply driving two AO Bus Boards, one for each of the two rows. There is an AC power inlet with switch and fuse on the back of the case.


Some of the modules I’ve built are based on commercially available PCBs originally designed for Eurorack or other formats, which I’ve mounted behind Kosmo size front panels. The rest use PCBs I or other Kosmo format builders have designed, in some cases based on existing circuit designs; others are original.

The above image shows Kosmodrome as the synthesizer existed in January 2024. Being modular, the synth is never “completed”. I’ve completed two “phases” of construction, and Phase 3 modules are in progress.

The modules are listed and described here:

Kosmodrome modules

Front Panels

One decision I made when I started Kosmodrome was to impose a more or less uniform front panel style. I’m not a great fan of the hodgepodge, crazy quilt look of a lot of Eurorack synths that have disparate panel designs from a dozen different makers. I do think the uniform appearance of Kosmodrome gives it a very striking look.

I went with black text/graphics on white, partly in contrarian reaction to the prevalence of BLACK BLACK BLACK modules among other Kosmo builders and partly for pragmatic reasons: It’s easier to print black on white than white on black, or black on anything else, with a laser printer, and many of my earlier modules used printed paper laminated to sheet aluminum panels. In the Kosmodrome era I’ve mostly used fabricated FR4, or in a few cases aluminum, but I’ve stuck with the color scheme.

I don’t know where the idea of an art deco theme came from, but I used it on the first (Eurorack) FR4 front panels I ever had fabricated and I’ve stuck with it since. I do the panel designs in Inkscape and the fonts are Limelight (for the module name and maker) and Copacetic (for the controls labels). Gaps in the rows are filled with blank panels with a graphic design that attempts to emulate art deco leaded glass windows.

Other components

Besides the modules, Kosmodrome includes some non-module components:

Other Kosmodrome components