New native pages for the Akai MPC500, loaded from a WAV file.
No hardware mod, no soldering, fully reversible.
MPC500 OS 1.31freeopen source
Open500 is a small loader added to the official MPC500 operating system. Once it is installed, add-ons are just WAV files: you load them from the CompactFlash like any sample, and they show up in the OTHER menu as native pages — same fonts, same cursor, same wheel and DO IT / CANCEL as the original OS.
Delete the add-on sample and it is gone. Reflash the original OS and your MPC is exactly as it came from Akai.
The add-ons use the MPC's own engine wherever they can (its time stretch, its sample editing, its pad playback), so what you hear in the preview is exactly what you get.
Every add-on works the same way: you hear the result on the pads before you commit, DO IT asks for confirmation, and your original sample is never modified.
12 live effects on the whole mix, SP-404 style: hold a pad, the effect plays while your beat keeps running.
Stutter, filter, trance gate, lo-fi, vinyl, scatter, delay, reverb, reverse, tape stop, chorus, tremolo. The slider drives the main parameter; timed effects follow the sequence tempo. Holding a pad shows the CPU load.
A 16-step grid sequencer on the MPC's display, editing your real sequence — even while it plays.
Hit a pad to pick the sound, move along the steps with the arrow keys and press QLINK to add or remove a hit. ↓ goes to bar / step / velocity, ↑ back to the grid.
Chop a loop into equal slices by BPM and lay them on the pads.
Set the tempo (B) and the number of slices (N). Pad 1 plays slice 1, pad 2 slice 2… DO IT, then hit the pad where the slices should start. Slices are set to mono, all in one mute group.
Chop on the hits: finds the transients and puts every hit on its own pad.
Turn SENS up to catch more hits (N shows how many). Cuts land a few milliseconds before each hit so attacks stay intact. Audition every slice on the pads, DO IT, hit the first pad. Mono, one mute group.
Put a loop in time with your beat, without changing its pitch.
It guesses how many bars the loop is (B) and takes your sequence tempo as the target (T), then uses the MPC's own time stretch (RTHM / PERC / MUSC / VOX). Listen on the pads, DO IT to keep it.
A chain of up to 8 effects printed into the sample: fades, gain, bit crush, downsample, drive, vinyl crackle, silence trim.
Turn the slot number (1–8), pick an effect and its amount for each slot: the pads play the whole chain while you turn the wheel. VINYL adds record hiss and crackle. DO IT saves the result as a new sample.
Swap, copy and clear pads: just the samples, or the whole pad with all its settings.
SWAP two pads (optionally with their MIDI notes, so your sequences keep playing the same sounds), COPY one pad to as many pads as you hit, CLEAR pads back to default. Asks before overwriting a full pad. Shortcut: SHIFT+STOP.
Keeps the line input open to the outputs: play a synth or a turntable over your beats.
Analog pass-through with adjustable level. It stays on in every page and pauses by itself while you sample.
The add-on manager. Load it first: it installs every add-on you load after it (up to 8 at the same time) and adds them to the OTHER menu.
Once. Takes about five minutes. You need a CompactFlash card and a computer.
Download the MPC500 OS 1.31 from Akai Professional and unzip it: you get mpc500.bin.
Drop mpc500.bin here. It is patched in your browser: nothing is uploaded.
We never distribute Akai's firmware: this page only adds the Open500 loader (1.3 KB of our own code) to the file you provide, checks that it is the untouched OS 1.31, and recomputes the checksum. The result is identical, byte for byte, to the firmware we tested.
Copy MPC500.bin to the root of the CompactFlash card and insert it in the MPC500.
Hold SHIFT while you switch the MPC on, then press REC when the screen asks for it. Wait for the update to finish.
Copy HUB.WAV and the add-ons you want (MASTERFX.WAV, GRID.WAV, CHOPAGE.WAV, TRANSCHP.WAV, AUTOWARP.WAV, SAMPLEFX.WAV, PADTOOLS.WAV, INTHRU.WAV) to the card. On the MPC, LOAD HUB.WAV first
(the screen shows LOADED hub), then the add-ons (LOADED <name>).
Open them from MODE → OTHER: the add-ons are listed after Version. Select one, press DO IT. CANCEL goes back.
HUB.WAV and the add-ons
in the MPC's autoload folder on the card: they load by themselves, in any order. Otherwise load them again after switching the MPC off.mpc500.bin (OS 1.31) the same way (SHIFT at power on, then REC).NO FREE SLOT (8 add-ons already loaded), BAD (damaged WAV),
LOW MEM: ADDONS! (sample memory almost full). SHIFT+ERASE reloads the add-on manager.Tested on one MPC500 with OS 1.31. This is an unofficial project, not affiliated with Akai Professional or inMusic. Use at your own risk.
Not yet. Open500 is built on a detailed study of the MPC500 OS 1.31; other models run different software.
No. Without add-ons loaded, the OS behaves like the original 1.31 — the only difference is 896 KB less sample memory, reserved for add-ons and effects. Your programs, samples and sequences are not affected.
Because the operating system belongs to Akai. Open500 only publishes its own code, and your browser combines the two on your computer.
Yes, that is the idea. The add-on SDK (Python, with an emulator to test add-ons before trying them on the MPC) will be documented in the repository.
Great — open an issue in the repository and describe it.
Open500 is free. If it is useful to you, a donation helps keep it going: paypal.me/SupportOpen500.