Sophie for Digitakt

Sophie is a metallic percussion synth machine for the original Digitakt (Mk1), OS 1.53 and 1.54. It began as a fixed-point adaptation of Sophie for Schwung by mestela and evolved into four different models: FUSE, BOOM, PIPE and SHARD. It uses Digitakt's regular AMP, filter, mixer and effects path. The source, not a modified Elektron OS, is what this repository distributes.

Changelog

• 1.2.0: SOPHIE's SRC and LFO pages are now drawn by elekloader's machine-pages mod (core 3.0), from a page SOPHIE describes, and its sound enters through machine-pages' render event. SOPHIE no longer patches those firmware places itself (1.1.13 patched 17), so it shares a build with the other machines made for machine-pages (checked: NEIGHBOR 0.7, DIGISLICER 2.3 and digi1_mods' Digi Mono, Digi Macro and Digi Poly, with digihealth, on OS 1.53 and 1.54). The pages, the knobs, their ranges, defaults and value texts, and the LFO page's names are as before. The render loop is also about 7 % smaller: ds_render_core drops from 936 to 863 M68k instructions and from 1,226 to 1,142 static estimated cycles, with output identical sample for sample on the golden corpus. These are static toolchain measurements; two active voices remain the practical limit without FAST AUDIO. SOPHIE is still machine 7: projects keep their SOPHIE tracks. Needs core 3.0 or later and machine-pages 1.1, both in elekloader's mod shop.
• OS 1.54: SOPHIE and the optional diagnostic also build for Digitakt OS 1.54, from the same source and with the same behavior: one .elemod for each OS. Needs elekloader 0.4.0 or later.
• S031: BR is replaced with Sophie’s FOLD wavefolder.

The current .elemod files are in release/; 1.1.13's stay there for an elekloader without core 3.0 and machine-pages (it builds alone, as before, but not beside other machines). The 1.2.0 files are generated from the current sources for OS 1.53 and 1.54.

USE AT YOUR OWN RISK. This modifies your instrument's firmware; back up your projects and sounds, and keep a stock OS file for recovery.

One instance runs without FAST AUDIO; the original hardware test found two instances practical with FAST AUDIO enabled. Eight-track operation is not claimed.

Controls

The custom controls can be parameter-locked. The normal AMP page controls the note envelope: set HOLD to NOTE for TRIG LEN to determine when the release begins. Use a finite DEC to hear that release. DEC INF can keep the sound going indefinitely. Retriggering chokes the previous voice on that track, with a brief transition to suppress a click.

SWEEP starts at zero. Turning right begins above the played pitch; turning left begins below it. Holding FUNC while turning uses the stock TUNE octave-step behavior (-60 to +24); ordinary turning reaches the complete -64 to +63 range.

Install: no compiler required

You need only the prebuilt Sophie mod for your OS (OS 1.53, OS 1.54), elekloader (0.4.0 or later for OS 1.54), and your own original Digitakt Mk1 OS 1.53 or 1.54 .syx The .elemod contains this project's code, not Elektron's firmware. You do not need ColdFire tools, Python, or a source checkout to install it.

1. Open elekloader and select your stock OS using Change stock firmware.
2. Choose Install from file and select digisophie-1.2.0.elemod (OS 1.53) or digisophie-1.2.0-os1.54.elemod (OS 1.54); elekloader refuses the file made for the other OS. Enable SOPHIE. It needs core 3.0 or later and machine-pages, which draws its pages: tick machine-pages in elekloader's mod shop (core 3.0 comes with it). If your elekloader shows a dependency error, update it before building.
3. Optional: install and enable the bundled digihealth diagnostic for your OS (OS 1.53, OS 1.54) too. This is the configuration used for the earlier S027 hardware test. It adds SYSTEM INFO and an opt-in FAST AUDIO setting; without it Sophie still works.
4. Wait for elekloader's Ready to build check, set the four-character OS version to S034, then choose Build Firmware. Save the generated .syx on your computer.
5. Send that .syx to the Digitakt with Elektron Transfer

Elekloader builds and verifies the OS; Elektron Transfer does the actual upload to the instrument. Do not power off during the update. Neither the stock nor modified OS file belongs in this repository.

Build the mods from source (developers only)

ColdFire tools are needed only to change or recompile the mod. You need Python 3.9+, a source checkout of elekloader, a ColdFire cross-toolchain (m68k-linux-gnu- or m68k-elf- assembler, GCC and linker), and your own stock OS 1.53 or 1.54 file. From this repository:

ELEKLOADER_CROSS=m68k-elf- sh scripts/build.sh \
  /path/to/your/Digitakt_OS1.54.syx /path/to/elekloader

This builds core, machine-pages, Sophie and the optional diagnostic from source for the OS of the file you give it, lints the combination, and writes the verified custom OS to out/Digitakt_OS1.54_SOPHIE_S034.syx (1.53 for a 1.53 file). To test DSP alone, run make test; make cross-check ELEKLOADER=/path/to/elekloader additionally compiles for ColdFire (the page uses elekloader's SDK header digitakt-mk1/core3.h). Optional emulator probes in tests/ require digiemu.

Use and recovery

This changes firmware on the instrument. Back up projects and sounds first, check that your stock OS is OS 1.53 or 1.54 for the original Digitakt, and keep that stock file for recovery. If you install the optional diagnostic, FAST AUDIO is off by default; SYSTEM INFO and FAST AUDIO can be enabled separately in SETTINGS. See diagnostics for the monitor.

Sophie is independent of, and not endorsed by, Elektron or the estate of SOPHIE. It contains no Elektron firmware or samples.

Source layout

The Digitakt addresses the mod uses are kept apart from the code that uses them: os153.inc / os154.inc for glue.s, os153.h / os154.h for digitakt.c. The OS 1.54 build defines OS154 (mod.json, under ports), which picks the 1.54 files; the OS 1.53 build is the same code. Since 1.2.0 the only firmware address left is the Bitmap vtable of the machine menu's icon: the pages and the render point are machine-pages'.

Source and licenses

The Sophie adaptation is MIT licensed. The original Sophie attribution and the separate GPL-2.0-or-later digihealth source are documented in THIRD_PARTY.md. The digihealth license is also included in its source directory.

The DSP audit, hardware performance notes, SPICE architecture idea and oscilloscope feasibility note record the development history; the latter two are ideas, not implemented features.