SU10-Kit

Build sample kits for the Yamaha SU10 on your computer, and load them into the sampler over MIDI.

The SU10 is a small 1990s phrase sampler with 384 KB of memory and no official way to get sounds in, other than recording them. SU10-Kit lets you put your own WAV files on its pads, choose quality, loop and volume per pad, and save a bulk dump that the SU10 loads like one of its own backups. It also works the other way: open a dump and get every pad back as a WAV.

• Open SU10-Kit-Builder in your browser: nothing to install
• su10kit.py: the same engine as a command-line tool (Python 3, no extra packages)

Not affiliated with Yamaha. Tested on one SU10 so far, so please share how it works on yours.

What you need

• A Yamaha SU10
• A MIDI interface (tested with a Yamaha UX16 and an M-Audio MIDISport)
• A program that sends SysEx files: SysEx Librarian on Mac, MIDI-OX on Windows

Back up your SU10 first. A failed transfer leaves it empty.

Building a kit in the browser

1. Open SU10-Kit-Builder. It starts with an example kit you can play.
2. Drop WAV files on the pads. Drop several at once to fill the empty pads in order.
3. Per pad, choose:
   • Quality: High, Standard, Long or Extra long (more quality = less sampling time)
   • Mono or stereo: stereo uses twice the memory
   • Play mode: one-shot, loop, or end-loop (plays once, then repeats the last part), with snap to zero crossing
   • Volume, normalize, pitch, start and end points, and cut silence
4. Watch the memory meter: everything has to fit in 384 KB.
5. Press Play to hear exactly what the SU10 will play.
6. Set the machine settings (MIDI channel, device number) and press Save kit.

You get a zip with <kit>_header.syx, <kit>_data.syx and a short pad list.

Sending the kit to the SU10

1. Send <kit>_header.syx.
2. Wait until the MIDI indicator on the SU10 goes off.
3. Send <kit>_data.syx, with a pause of 110–150 ms between messages (in SysEx Librarian: Pause between messages).

Below about 100 ms the SU10 says Wrong Data. At 150 ms a full kit takes about 5 minutes.

If nothing happens at all, check the device number: the SU10 ignores dumps made for another DevNum.

Backing up the SU10

1. In SysEx Librarian, press Record One.
2. On the SU10: Utility → Bulk → send. The 15-byte header arrives and Record One stops.
3. Immediately press Record Many. At each "Next OK" on the SU10 (4 %, 36 %, 68 %), press OK.
4. Click Done when the SU10 has finished.

Keep both files together: they are one backup.

The command-line tool

python3 su10kit.py build  "My Kit/"                         # every WAV in the folder on its own pad
python3 su10kit.py build  "My Kit/My Kit.txt"               # a kit list with settings per pad
python3 su10kit.py info    backup_header.syx backup_data.syx
python3 su10kit.py extract backup_header.syx backup_data.syx wavs/

A kit list looks like this (see examples/example-kit.txt):

channel 10
record Long mono
pad 1: bell.wav     High   mono   one-shot  autotrim  normalize
pad 2: bass.wav     Long   mono   loop      vol 90
pad 3: strings.wav  High   stereo endloop 1.25

Run python3 su10kit.py for all options, and python3 tests/test_su10kit.py to check it works on your machine.

Good to know

• Memory per second: High ≈ 20 KB/s mono, Standard ≈ 14.5, Long ≈ 10, Extra long ≈ 7. Stereo doubles it.
• Normalize to −6 dB (the default) leaves headroom; 0 dB can sound crushed on the SU10.
• All 48 pads (banks A–D) respond over MIDI whatever bank is selected: pad A1 is C1 (note 36), pad D12 is note 83.
• Pitch, filter amount and crossfader are live controls and are not stored in a kit.

How it works

The SU10 stores its samples as 4-bit IMA ADPCM, a common audio format, packed into Yamaha's SysEx messages. The full format is in FORMAT.md.

Credits

Made by Maurice Hissink (harmonicworks.org).

The format was decoded and the tool written together with Claude, an AI model by Anthropic: the AI did the decoding and the code, the testing on the real SU10 was done by hand. The full story is on the blog.

Licence

MIT, see LICENSE.