Cycles One-Shot

A sampler machine for the Elektron Model:Cycles, OS 1.13. It adds SAMPLE as a 7th machine next to the six stock ones and plays samples from the +Drive, once per trig, and in model27's builds also in a loop and in reverse. You choose a sample in the OS's own PRESET browser, and it is saved with the sound.

The goal for now is the Model:Samples' sampler on the Cycles, in sound and in features. The sound is there: SAMPLE plays a sample the way the Model:Samples does, with 6-tap interpolation at twice the rate, then a 2:1 decimator. Nothing of it is copied from Elektron. The interpolation and its table are our own design and code; the decimator is the one the Cycles OS already has, which SAMPLE calls where it is (the Model:Samples uses the same). Start, Length and the filter work as on the Model:Samples; the filter follows its measured laws with our own design and code. Loop and reverse work as on the Model:Samples too, as two switches of model27's builds (below).

Features

• SAMPLE, a 7th machine. It sits on the MACHINES page next to the stock machines and works with the sequencer, locks and the amp chain like them.
• Samples from the +Drive. Choose a sample in the PRESET browser on a SAMPLE track. The sound takes the sample's name and keeps the choice in projects, kits and presets. Hold a step while you open a sample, and the step plays it as a sample lock.
• Clean playback. 6-tap polyphase interpolation at 96 kHz, as on the Model:Samples, then the Cycles' own decimator. A sample recorded at another rate keeps its pitch, and stereo files play as mono.
• Start and Length as on the Model:Samples. Both run from 0 to 120, so moving Start keeps the length and 120 splits evenly into slices.
• Start and Length act on the note that plays. Turn Length, or let an LFO move it, and a note that plays once ends where Length now puts it, with its 4 ms fade-out whole even when the end moves behind the playhead. Its start stays where the trig put it, so an LFO on Start still gives each trig a start of its own. A loop takes the window as the Model:Samples does: its end at once, its start from the next time round. Move Start on a loop and the loop wanders with it.
• No clicks at the edges. 4 ms fades at the end of what a trig plays, and at its start when Start lies inside the sample. A sample played from its first frame keeps its attack. A trig that cuts a note still sounding brings the new one in over 0.67 ms, as the Model:Samples does.
• Loop and reverse, in model27's builds. Hold RETRIG and press PUNCH for Loop, GATE for Reverse; on a SAMPLE track that flips the switch instead of PUNCH or GATE, and their LEDs show the switches while RETRIG is held. Both are saved with the sound, and the name's box ends with L or R while they are on. Loop plays what Start and Length select again and again with a hard seam, as on the Model:Samples, so a single cycle of a waveform loops without a step; the note then plays until DECAY has closed it. Switched off, a loop plays to the end of the window (at least 4 ms on) and fades out. Reverse plays the window from its end to its start, from the next trig on; both together loop backwards. The switches come from model27's shortcut layer, so One-Shot's own image plays one shot, forward.
• The Model:Samples' filter. One knob, SWEEP, closes a lowpass to the left of 64 and a highpass to the right; CONTOUR adds resonance, up to a +27 dB peak at the cutoff. Frequency, resonance and how the resonance thins out towards the top follow the Model:Samples, measured on its OS and rebuilt from scratch: a 2-pole filter on the ColdFire's EMAC, about 800 instructions per track and block. At 0 (the default, the knob's middle) the track is untouched, bit for bit. Across the middle and from one side to the other the filter fades rather than switches, so a square, ramp or random LFO on Cutoff, a p-lock or the knob itself does not click. One difference: the filter runs inside the machine, after the amp envelope and before Volume + Dist, where the Model:Samples has it after. Volume + Dist is a stage of the OS's track chain that runs after every machine, so putting the filter behind it would mean changing that chain for all tracks. You hear the difference only with DIST above 0: the distortion then acts on the filtered signal. The laws, the structure and the measurements are in TECHNICAL.md, section 16.
• The Model:Samples' pictures for Cutoff and Reso. While SWEEP or CONTOUR turns on a SAMPLE track, the knob view shows the Model:Samples' own pictures of its filter instead of SNARE's: the lowpass's edge moving up and turning into a highpass, and a peak growing at the edge. The Cycles' OS carries them already, built at start-up though nothing in it draws them, so One-Shot adds no graphics of its own.
• A waveform view. On a SAMPLE track the main screen shows a narrow column on the left: the current pattern's number (A01 to F16), TRAK with the track's number, and the track's level as a bar that moves while you turn LEVEL. To its right the sample's name sits in a box like the OS's own browser title, and below it the waveform. Lines mark where a trig starts and stops; they move while you turn Start and Length. Hold a trig and turn Start or Length to lock them, and the whole screen shows the view for that trig while you turn: its locks on the waveform, and with a sample lock that sample and its name. When the value goes, the trig's note, velocity and length are back on the left.
• An upload page, online at https://durchgemacht.github.io/cycles-one-shot/uploader/ (the same files as uploader/). It puts audio files on the +Drive over USB from Chrome or Edge, as samples SAMPLE plays, and deletes samples and folders from it (the × on a row, after asking; a folder goes with everything in it). It needs no firmware change, so it works with the official OS as well. In the folder /Wavetables, which model27's CHORD Tables plays as wavetables, it does not write a file CHORD Tables cannot play (not 1 to 32 frames of 256 samples, as a 48 kHz WAV), and it warns about a file whose first frame is not a sine: on such a table SWEEP 0 plays no sine.

Status

• Machine 0.14 (on a SAMPLE track, Cutoff and Reso show the Model:Samples' pictures in the knob view, taken from the Cycles' own OS): host-tested, and One-Shot's own image tested in the digiemu emulator and on a Model:Cycles (2026-11-04). Not yet in a build of model27.
• Machine 0.13 (Start and Length act on the note that plays: once, Length moves its end; a loop takes its end at once and its start from the next time round): host-tested, and tested in a build of model27 with the switches, in the digiemu emulator and on a Model:Cycles (2026-11-02). One-Shot's own image, without the switches, is host-tested; not yet on a device on its own.
• Machine 0.12 (with a trig held, turning Start or Length shows the whole view for that trig: its locks on the waveform, a sample lock's sample and name; NoteVelocityView's draw goes through SAMPLE's view for that): host-tested, and tested in the digiemu emulator and on a Model:Cycles (2026-10-30).
• Machine 0.11 (Loop and Reverse as switches for model27's shortcut layer, L and R in the name's box; a trig that cuts a sounding note fades the new one in over 0.67 ms; a voice whose amp envelope has closed lets go of its sample): host-tested, and tested in model27's build with the switches, in the digiemu emulator and on a Model:Cycles flashed from model27's web flasher (2026-10-26). One-Shot's own image, without the switches, is host-tested; not yet on a device on its own.
• Machine 0.10 (a column on the left with the pattern's number, the track's number and its level; the waveform 105 pixels wide to its right): tested on a Model:Cycles (2026-10-25), and in the digiemu emulator.
• Machine 0.9 (the bar above the waveform split in two boxes: the current pattern's number on the left, the sample's name on the right): tested on a Model:Cycles (2026-10-24), and in the digiemu emulator.
• Machine 0.8 (for builders that compose machines from compiled objects, like model27's: with CM_SYMBOLS defined, the machine index and the first descriptor are undefined symbols the builder resolves when it places the object, and each assembly file has a section of its own; without it, the build is byte for byte the 0.7 build): One-Shot's own build is unchanged, the symbol build tested in the digiemu emulator through model27's composer (2026-10-21), alone and next to a second added machine; not yet on a device.
• Machine 0.7 (registered through Modded-Cycles' own registrar for added machines, the one MACRO and ACID use, so that a combined build can hold several added machines; the payload moves to 0x43000000 and the sample pool to 0x43800000–0x46700000, 47 MB; what it conflicts with is computed from the clone's tweaks instead of listed by hand): host-tested, checked with Modded-Cycles' own overlap checker, registry and build, alone and with fifteen other mods, and tested on a Model:Cycles (2026-10-21).
• Machine 0.6 (the filter fades across the middle and between its sides instead of switching, after a report that a square, ramp or random LFO on Cutoff clicked in 0.5): tested on a Model:Cycles (2026-10-20), and in the digiemu emulator.
• Machine 0.5 (the filter, Cutoff shown as −64 … 63): tested on a Model:Cycles (2026-10-18), and in the digiemu emulator. A sound saved by 0.4 or earlier loads with the filter off.
• Machine 0.4 (waveform view, Start and Length as on the Model:Samples, fades): tested on a Model:Cycles (2026-10-17), and in the digiemu emulator.
• Upload page 0.3 (a Back button to the folder above, instead of the small .. row): host tests, and in a browser against a stand-in Cycles; not yet with a Model:Cycles.
• Upload page 0.2 (deleting files and folders): host tests against a stand-in Cycles, and tested on a Model:Cycles (2026-10-26). A sample that is loaded plays on until no sound names it or the Cycles restarts; after that a sound that names it stays silent.
• Upload page 0.1: tested with a Model:Cycles (Chrome on macOS).
• Limits: SAMPLE is a tweak of its own, so it cannot be installed next to another tweak that adds machines (MACRO, ACID, the Syntakt engines, the SD Vintage variants) until a combined build exists; nor with Model-TG or Modded-Cycles' track filter, which hook the same sound record functions of the OS; nor with sample preview. The build computes that list from the clone's tweaks. Every other mod of Modded-Cycles 1.55 combines with SAMPLE at the byte level, checked with Modded-Cycles' own tools, but not yet tried together on a machine. Loop and Reverse need model27's shortcut layer; there SAMPLE does not go with lfo-plus (LFO 2, 3, 4), which keeps LFO 2's depth where the switches are saved.
• Not One-Shot's doing: when loading a project asks "Save … before loading?", Yes saves the project you leave but does not load the other one. The official OS 1.13 does the same.

Getting started

1. Build the image from your own copy of the official model-cycles_OS1.13.syx. You need Python 3, the m68k-elf toolchain (Homebrew: m68k-elf-gcc, m68k-elf-binutils) and a clone of Modded-Cycles at a release with the mod picker (1.53 to 1.56: the build calls its registrar for added machines, gen_macro.added_machine):

   python3 machine/build.py --stock model-cycles_OS1.13.syx --modded-cycles path/to/Modded-Cycles
   

   This writes build/model-cycles_OS1.13-sampler-v0.14.syx and build/sampler-tweak.json, the same machine as a tweak file Modded-Cycles' own tools/build.py accepts, and checks every change against the stock bytes.

2. Install it over USB the way you install an official OS update. To go back, first set every SAMPLE track to one of the six stock machines (a project that still names a machine the official OS does not have can freeze its MACHINES page), then install the official 1.13 file the same way.

3. Put samples on the +Drive. Samples already there, for example from the Model:Samples OS, work as they are. For new ones open https://durchgemacht.github.io/cycles-one-shot/uploader/ (or uploader/index.html from your copy) in Chrome or Edge, press Connect, pick a folder and upload. Close Elektron Transfer first, which would hold the MIDI port.

4. Play. Set a track to SAMPLE, open the PRESET browser (FUNC + MACHINE) and open a sample.

If Chrome refuses MIDI to the page opened from disk, serve the folder locally and open http://localhost:8000:

python3 -m http.server --directory uploader 8000

Documentation

TECHNICAL.md explains how it works: how the parts of the OS that One-Shot touches work, where and how it hooks in, the sound core and its measurements, the filter with its laws and how close it comes to the Model:Samples', the USB file commands, notes on the Model:Samples OS, and how to build, test and try it in an emulator.

License

MIT, see LICENSE. The repository holds no Elektron firmware: the build starts from your own copy of the official file, and the Model:Samples table used for comparison is read from your own copy of that OS and stays in build/. The protocol facts of the upload page come from ModdedTransfer (WTFPL) and Model-TG (MIT); the machine-adding tools are Modded-Cycles' (MIT).