SP-404A hardware reference — effects, techniques, limitations, and SD card structure. Use when the user asks about "SP-404 effects", "how to resample", "what effects should I use", "hardware limitations", "SD card setup", "PAD_INFO.BIN", "pattern files", "RLND chunk", or needs guidance on what the sampler can and can't do.
The Roland SP-404A (original, not MK2) is a compact phrase sampler with:
/Volumes/SP-404SX/
└── ROLAND/
└── SP-404SX/
├── SMPL/ # WAV sample files + PAD_INFO.BIN
│ ├── PAD_INFO.BIN
│ ├── A0000001.WAV ... A0000012.WAV (Bank A)
│ ├── B0000001.WAV ... B0000012.WAV (Bank B)
│ └── ...through J
└── PTN/ # Pattern files
├── PTN00001.BIN ... (Bank A patterns)
└── ...
{BANK_LETTER}0000{PAD_NUMBER}.WAVG0000007.WAV = Bank G, Pad 7Per-pad metadata file at ROLAND/SP-404SX/SMPL/PAD_INFO.BIN.
Generated by scripts/gen_padinfo.py.
Auto-sets:
SP-404A WAVs include a proprietary "RLND" chunk (466 bytes) encoding device ID and pad index. Injected by scripts/wav_utils.py:inject_rlnd() during sample conversion.
Pattern files (.PTN) in ROLAND/SP-404SX/PTN/ are proprietary binary format. Generated via scripts/gen_patterns.py using vendored spEdit404 (scripts/spedit404/).
The SP-404A has 29 built-in effects. See references/effects-table.md for the full list with knob assignments and suggested use cases.
| Effect | Best For | Notes |
|---|---|---|
| Vinyl Sim | Adding warmth/lo-fi character | Classic SP-404 sound |
| DJFX Looper | Glitch, stutter, live chops | Real-time performance tool |
| Isolator | Live mix control, frequency cuts | Essential for transitions |
| Filter + Drive | Aggressive textures, buildups | Combine for intensity |
| Delay | Dub effects, space | Tempo-synced |
| Reverb | Ambient washes, depth | Use sparingly on drums |
| Compressor | Punching up drums, glue | Subtle settings work best |
Resampling is the SP-404's superpower — recording the output back onto a pad:
Common resample chains: