Blue_Lantern

Survival // your ticket in

Modular is expensive. The case shouldn't be what stops you.

Build a 3U + 3U + 1U Eurorack case for under $200 using hardware-store wood rails, then fill it with free, open-source module files.

Start the case build Skip to module files
~$200total case cost
~$40of that is wood
3U+3U+1U24" wide rows
12open module projects

Tutorial

Build the wood-rail case

  1. Cut the sides

    Cut two side pieces to 12.5" long, about 4" tall.

    Close-up of the freshly cut end of a thin pine board, raw end grain showing, a price sticker on its face.
    The cut end of a side piece

  2. Cut the rails

    Cut all rails to 24". Use the wider stock for the outer edges and the thinner stock where power connectors need clearance.

    Seven pine rails of equal length laid side by side across a black desk.
    Rails cut to 24 inches
    One narrow pine strip lying across a wider board, a store barcode label still on it.
    Rail stock from the hobby-wood aisle

  3. Cut the backboard

    One 24.5" × 12.5" piece, or three narrower boards that add up to it.

    Several wide pine boards and two thin strips laid out flat on a workbench beside a modular synth.
    Boards for the backboard

  4. Glue and pilot the frame

    Run Liquid Nails on each joint, drill pilot holes, and drive screws by hand to clamp the frame while it dries. Add the 12.5" square brace for strength.

    A tube of Liquid Nails Projects adhesive above a pine rail with two thin beads of glue run along its length.
    Two beads of Liquid Nails on a rail
    A side board glued upright against a rail on a workbench, held in place by a tub and a bottle set against it while it dries.
    Weighted while the glue sets
    A gloved hand holds a wood screw beside a drill bit in a drill chuck to compare their thickness.
    Match the pilot bit to the screw
    A gloved hand holding a screw against a drill bit in a drill chuck, close up.
    The bit against the screw, close up
    A clear box of Hillman #6 by 5/8 inch flat Phillips wood screws, 100 pieces.
    #6 x 5/8 in. wood screws

  5. Set the rail spacing

    Space the 3U rail pairs about 4.5" apart and the 1U pair about 1.25". Check heights with real blank panels before the glue sets.

    End view of the frame: rails stand in pairs against a side board, a screw head in the side, and a black Eurorack panel behind for spacing.
    Rail pairs checked against a real panel
    The glued frame lying flat with three open rows, a black Eurorack panel fitted in the top corner to test the spacing.
    A test panel in the top row

  6. Patch any splits

    Fill split wood and small gaps with the same glue. It's paintable.

    [ photo needed: patched joint ]

  7. Paint (optional)

    Spray paint the frame once it's fully dry.

    [ photo needed: painted frame ]

  8. Drop it in the ABS case

    Line the case with weatherstrip tape and trim its foam to fit the sides. The frame sits snug, no screws needed. The lid still closes with cables patched.

    The empty black ABS case open, a roll of foam weatherstrip tape and its package lying inside.
    Weatherstrip laid in the empty case
    The frame sitting inside the black case, seen from above at an angle, three rows of rails.
    The frame dropped into the case
    Close-up of a corner of the case: the frame sitting snug against the black foam lining.
    Snug against the foam lining

  9. Install power

    Fit a 4ms or Synthrotek DC-DC power setup. Never a linear wall transformer.

    Inside the case: two green power bus boards fixed to the backboard between the rails, red and yellow power wires running to a power board at the top.
    Bus boards fixed between the rails
    The frame in the black case, egg-crate foam in the lid, two green bus boards and a power board wired across the rails.
    Power wired, foam in the lid

  10. Mount modules

    Mark each mounting hole with a Sharpie, start it with a small pilot bit, then drive the screw by hand.

    [ photo needed: first module mounted ]
The bare frame
The finished wooden frame standing on a bench, front view, three rows of rails across a pale backboard.
Front
The finished frame lying on the floor, seen from a low angle along its length.
Along the rails
The finished frame stood on its end, rails running vertically, black Eurorack panels at either end.
Stood on end with panels
Looking down the side of the finished frame where the side board meets the backboard.
The side board
Power safety

Don't use a linear wall-transformer supply in this case. It won't fit the ~4" of clearance and it's a safety hazard. A DC-DC converter setup from 4ms or Synthrotek is the way to go.

All 71 photos from the build, in the order they were taken. Select one to open it full size.

  • Several wide pine boards and two thin strips laid out flat on a workbench beside a modular synth.
  • Two pine boards close up, each with a store barcode and a wood-dust warning label.
  • Two pale pine boards stacked, each with a barcode label and a warning sticker.
  • Two thin pine strips held over a dark floor, each with a barcode and a warning label.
  • Pine boards and a thin strip stacked on a black table, a California wood-dust warning label on one.
  • One narrow pine strip lying across a wider board, a store barcode label still on it.
  • Close-up of the freshly cut end of a thin pine board, raw end grain showing, a price sticker on its face.
  • Six pine rails laid side by side on a black desk, seen from above, cables and gear around them.
  • Seven pine rails of equal length laid side by side across a black desk.
  • A tube of Liquid Nails Projects adhesive above a pine rail with two thin beads of glue run along its length.
  • A cluttered workbench: a pine rail with a bead of glue along it, a tube of Liquid Nails, pliers, a small board, black pin headers and a red circuit board.
  • A tube of Liquid Nails Projects adhesive lying on two stacked pine rails.
  • Two pine rails glued together face to face, resting on the edge of a workbench.
  • A side board glued upright against a rail on a workbench, held in place by a tub and a bottle set against it while it dries.
  • The open frame on a workbench with two black Blue Lantern panels set in its rows to check the spacing.
  • A black Lunar Modulation Lab panel resting on the frame's rails, close up, black pin headers on the bench beside it.
  • The bare frame before its backboard, sides and two rails glued together, seen at an angle on a workbench.
  • A red Phobos VCF panel and a black Blue Lantern panel set side by side across two rails of the frame.
  • The frame on the bench with three panels set across its rails: two black ones in the top row and a red Phobos panel in the middle.
  • One end of the frame with a black panel set across the top rails and the lower row empty.
  • The frame stood on end, rails rising from the bottom side board, which is fixed with a screw; a black panel with jack holes sits behind the rails.
  • The frame stood upright in front of storage shelves, its tall rail pairs joined top and bottom by side boards.
  • End view of the frame: rails stand in pairs against a side board, a screw head in the side, and a black Eurorack panel behind for spacing.
  • Close-up of the bottom corner of the upright frame: a rail pair standing on the side board, a screw in the board's edge, a black panel with round holes behind.
  • Close-up of rails meeting the bottom side board of the upright frame, two screws in its edge.
  • The bottom of the upright frame, a black Lunar Modulation Lab panel fitted across the lowest rails.
  • The frame standing upright against shelves, a black panel fitted at the bottom of one row.
  • The top of the upright frame in front of shelves of parts bins, the rail pairs joined by a side board.
  • The frame lying flat on a gray concrete floor, a loose rail laid diagonally across it and a black Lunar Modulation Lab panel in the top corner.
  • The frame on a concrete floor seen from one end, three rows of rails with a black panel in the top corner.
  • Close-up of a black Lunar Modulation Lab panel resting across the top two rails in the frame's corner.
  • One end of the empty frame on a concrete floor, where a side board joins the rails.
  • The glued frame lying flat with three open rows, a black Eurorack panel fitted in the top corner to test the spacing.
  • A clear box of Hillman #6 by 5/8 inch flat Phillips wood screws, 100 pieces.
  • A gloved hand beside an open plastic box of small zinc wood screws.
  • A plastic pack of Hillman #6 by 5/8 inch flat Phillips wood screws lying on its side.
  • A plastic pack of Hillman #6 by 5/8 inch flat Phillips wood screws, 100 pieces, face up.
  • A gloved hand holds a wood screw beside a drill bit in a drill chuck to compare their thickness.
  • A gloved hand holding a screw against a drill bit in a drill chuck, close up.
  • The finished frame stood on its end, rails running vertically, black Eurorack panels at either end.
  • The frame stood on end on the workbench, looking down its rail rows to a black panel at the bottom.
  • Looking down the side of the finished frame where the side board meets the backboard.
  • The back of the upright frame, its tall backboard carrying a warning label, beside a cluttered workbench.
  • The frame with its backboard, leaning at an angle against cabinets, a black panel fitted at the bottom of one row.
  • The finished frame lying on the floor, seen from a low angle along its length.
  • The finished frame lying on its back on a garage floor, seen along its length, store labels still on the rails.
  • The finished frame stood on end on a garage floor, seen from the side, a drill beside it.
  • The frame stood on end on the garage floor, a closer view of its side board and screws.
  • The finished wooden frame standing on a bench, front view, three rows of rails across a pale backboard.
  • The finished frame standing on a black desk, its three rows in front view, a full Eurorack system with patch cables beside it.
  • Front view of the finished frame on a desk: three rows of rails across a pale backboard.
  • The finished frame on a desk at an angle, a spray bottle beside it.
  • Side view of the finished frame, screws visible along its side board.
  • The finished frame held upright in front of an open black ABS case.
  • The frame set down inside the open black ABS case, filling it.
  • The frame sitting inside the black case, seen from above at an angle, three rows of rails.
  • Close-up of the frame inside the black case, its rails and pale backboard.
  • Looking straight down into the open case with the frame fitted inside.
  • The frame fitted in the open case, seen from one end.
  • A gloved thumbs-up over the frame sitting in the open black case.
  • The frame in the open black case with two modules, one red and one black, set in the top row.
  • Close-up of a red Phobos VCF panel and a black Blue Lantern panel side by side on the frame's rails.
  • The empty black ABS case open, a roll of foam weatherstrip tape and its package lying inside.
  • Close-up of the weatherstrip package label: 3/8 inch high by 1/2 inch wide by 10 feet long, for large gaps.
  • The inside of the empty case, its molded floor and walls, before the frame goes in.
  • The frame in the black case, egg-crate foam in the lid, two green bus boards and a power board wired across the rails.
  • Close-up of a corner of the case: the frame sitting snug against the black foam lining.
  • Inside the case: two green power bus boards fixed to the backboard between the rails, red and yellow power wires running to a power board at the top.
  • The open case with the frame inside, the bus boards and power wiring fitted, foam in the lid.
  • The black ABS case closed and latched, resting on an office chair.
  • The closed case on the chair from another angle, its latches along the front.

Step two // fill the case

Open module files

Blue Lantern layouts of Mutable Instruments open-source designs. Same parts as the originals unless noted. Each project points you to the current recommended file.

Never soldered a module before?

Start with step-by-step build guides from Onion Madder's Mess O' Pedals, one action per step, then come back for these files.

Learn to build a module

Macro VCO MK2

Based on Braids
Euro

Updated 2019 Braids layout. Same parts as the original.

  • public-mk2-macro_vco-v1.4.zipRecommended // 4.2 MB
    Download
  • public-mk2-macro_vco.zipExtra // 4.2 MB
    Download

Resonator

Based on Rings
12HP

Adds a mute output button and an improved analog output path.

  • public_file-2020-resonator-rings_v2.0.zipRecommended // 9 MB
    Download
  • led_resistor_values_optimized.zipExtra // 224 KB
    Download
  • public_diy_12hp-rings-1.3fx.zipRetired, not recommended // 12 MB
    Download

LED brightness fix: add 2× 150Ω, 2× 390Ω and 1× 2K (0805, 1%) to the BOM.

Mycelium Synthesizer

Based on Plaits
Euro

Alternate Plaits layout using 0805 parts.

  • public_file_-mycelium_synth-1.2.1f.zipRecommended // 7.6 MB
    Download

Cyanescens VCO

Based on Tides v1
Euro

2020 Tides v1 layout running Sheep firmware.

  • public_file_tides-version1-cyan-vco-v2.0.zipRecommended // 7.9 MB
    Download

Stropharia

Based on Warps
12HP

Warps firmware with Parasites panel graphics.

Black panel labeled STROPHARIA propped against a brick wall: CARR IN, MOD OUT, TIMBRE, AUX OUT and MOD IN jacks, white CARRIER VCA, CV and MODULATOR VCA knobs, a mushroom and waveform drawing, a list of algorithms, and a large black ALGO knob.
The Stropharia panel
  • public-file-stropharia-v1.0.1.zipRecommended // 16.9 MB
    Download
  • public-diy_warps_v1.3f.zipRetired, not recommended // 435 KB
    Download

Grains

Based on Clouds
12HP

Granular processor on Clouds firmware. Tabletop EXTF 7.5 version available too.

  • public_grains_v1.4f.zipRecommended // 10.5 MB
    Download
  • public_file-extf-7.5-5.5-grains-2.1.1ftx.zipExtra // 14.6 MB
    Download

Built a 1.3f board? There is a quick silkscreen fix in fixes_for_v1.3f.txt.

Parallax Dual VCF

Based on Blades
Euro

Dual filter from the 2022 open-source Blades design. SOIC and 0805 parts.

Black Eurorack panel labeled parallax filter, two filter channels side by side: INPUT, 1V OCT and OUT jacks for each, FM CV, REZ CV, DRIVE and TYPE jacks, white DRIVE and REZ knobs, large black CUT knobs, a central MODE knob between PARALLEL, SINGLE and SERIES markings, a SHIFT toggle and a mushroom drawing.
The Parallax filter panel
  • public_file-pax_dual_vcf-1.2.zipRecommended // 23.2 MB
    Download
  • help_resistor_presicion.zipExtra // 91.7 MB
    Download

Use 0.1% resistors where marked. Do not use SSI2164; AS2164 or V2164 SOIC only.

Blades Single

Based on Blades
6HP

Single-channel Blades filter in 6HP.

Narrow black panel labeled PF, with a large CUT knob, white REZ, FM and DRIVE INPUT knobs, a red LED, VCA, DRIVE, FMOD, IN and 1V OCT jacks, and LPF, HPF and BPF outputs at the bottom around a flask drawing.
The PF panel
  • public_6hp_pf_blades-v1.2.2.zipRecommended // 17.1 MB
    Download

MIDI to CV

Based on Yarns
10HP

Runs stock Yarns firmware. Build help and large PCB photos included.

  • public-mtcv-v5-10hp_confirmed.zipRecommended // 4.9 MB
    Download
  • build_help_midi_to_cv_module.zipExtra // 3.9 MB
    Download
  • enhanced_diy_yarns_project_v2.5f.zipConfirmed // 1.5 MB
    Download

BASICS

Based on Peaks
Euro

CV on every knob and software calibration, no trimmers.

  • public_basics_v2f_peaks.zipRecommended // 11.4 MB
    Download
  • basics-peaks-dmc-v0.7_beta-firmware.zipExtra // 101 KB
    Download

Alt firmware (Tim Churches, v0.7 beta) needs an FTDI programmer.

Grids MK2

Based on Grids
12HP

Slimmer 2021 layout. Original-width version with MIDI in also available.

Black panel labeled grids, with FILL 1, FILL 2 and FILL 3 jacks, accent and trigger outputs, RESET and TAP, black XMAP, CHAOS, YMAP, X MAP, CLOCK and Y MAP knobs, orange and red LEDs, and DRUM 1, SNARE 2 and METAL HH 3 outputs along the bottom beside a bee drawing.
The Grids MK2 panel
  • public-grids-mk2-v1.2f_2021.zipRecommended // 4.9 MB
    Download
  • public-grids-v2.2f.zipConfirmed // 6.9 MB
    Download

Mini O_C

Based on Ornament & Crime
10HP

Compact O_C using the same OLED screen.

  • public-10hp_o_c_d-module_1.3f.zipRecommended // 6.5 MB
    Download

License & credits

All files are free under CC-BY-SA: download, modify, remix and share, as long as you credit and share alike. Original designs by Émilie Gillet (Mutable Instruments); Blue Lantern layouts by Flavio Mireles; alternate Peaks firmware by Tim Churches.

Read CC-BY-SA