Elektron OT & A4 MIDI CC chart, NRPN and OSC map¶
The Elektron OT & A4 MIDI implementation: 36 CC, 33 NRPN, each named, for Claude (MCP), SuperCollider or any OSC app.
| Device | Elektron OT & A4 |
|---|---|
| Vendor | Elektron |
| OSC prefix | /ot_a4 |
| Source | 🎛️ Derived from an Electra One community preset |
| Revision | per Electra preset |
| Upstream | electra-preset |
| Driver file | devices/elektron/ot_a4.json |
Not tested on the device yet
This driver comes from documentation or community data and has not been checked on real hardware. If you own one, a quick test and a pull request promoting it helps everyone — see CONTRIBUTING.
How do you control it?¶
Find the MIDI ports, then start the bridge with this driver:
osc-bridge detect # prints the ready-to-run line for what is plugged in
osc-bridge run --device devices/elektron/ot_a4.json --out-port <N> --in-port <M>
Then send OSC to 127.0.0.1:7777, for example:
From Claude or any MCP client, the osc-bridge mcp server exposes this driver as ot_a4: ask “what can the Elektron OT & A4 do?” and it reads this map with list_routes. See the MCP guide.
MIDI CC and NRPN parameters (69)¶
| OSC address | CC | NRPN (MSB/LSB) | Range | Nature | Section |
|---|---|---|---|---|---|
/ot_a4/tr1_lfo_speed |
28 | 0–127 | continuous | ||
/ot_a4/filter_lp |
34 | 0–127 | continuous | ||
/ot_a4/reverb_mix |
45 | 0–127 | continuous | ||
/ot_a4/filter_lp |
34 | 0–127 | continuous | ||
/ot_a4/delay_time |
40 | 0–127 | continuous | ||
/ot_a4/arm |
52 | 0–127 | continuous | ||
/ot_a4/tr1_lfo_depth |
31 | 0–127 | continuous | ||
/ot_a4/filter_hp |
35 | 0–127 | continuous | ||
/ot_a4/reverb_time |
40 | 0–127 | continuous | ||
/ot_a4/filter_hp |
35 | 0–127 | continuous | ||
/ot_a4/delay_fb |
41 | 0–127 | continuous | ||
/ot_a4/delay_send |
45 | 0–127 | continuous | ||
/ot_a4/delay_time |
40 | 0–127 | continuous | ||
/ot_a4/delay_fb |
41 | 0–127 | continuous | ||
/ot_a4/delay_send |
45 | 0–127 | continuous | ||
/ot_a4/filter_lp |
34 | 0–127 | continuous | ||
/ot_a4/delay_time |
40 | 0–127 | continuous | ||
/ot_a4/arm |
52 | 0–127 | continuous | ||
/ot_a4/filter_lp |
34 | 0–127 | continuous | ||
/ot_a4/delay_time |
40 | 0–127 | continuous | ||
/ot_a4/arm |
52 | 0–127 | continuous | ||
/ot_a4/filter_hp |
35 | 0–127 | continuous | ||
/ot_a4/delay_fb |
41 | 0–127 | continuous | ||
/ot_a4/delay_send |
45 | 0–127 | continuous | ||
/ot_a4/filter_hp |
35 | 0–127 | continuous | ||
/ot_a4/delay_fb |
41 | 0–127 | continuous | ||
/ot_a4/delay_send |
45 | 0–127 | continuous | ||
/ot_a4/tr5_mute |
49 | 0–127 | continuous | ||
/ot_a4/tr6_mute |
49 | 0–127 | continuous | ||
/ot_a4/tr7_mute |
49 | 0–127 | continuous | ||
/ot_a4/aux_3_4_mute |
49 | 0–127 | continuous | ||
/ot_a4/aux_3_4_cue |
51 | 0–127 | continuous | ||
/ot_a4/tr3_mute |
49 | 0–127 | continuous | ||
/ot_a4/tr4_mute |
49 | 0–127 | continuous | ||
/ot_a4/request_all |
61 | 0–127 | continuous | ||
/ot_a4/rec_arm_t5 |
53 | 0–127 | continuous | ||
/ot_a4/f1_frq |
1 / 40 | 0–16383 | continuous | ||
/ot_a4/f1_res |
1 / 41 | 0–16256 | continuous | ||
/ot_a4/f1_ovr |
1 / 42 | 0–16256 | continuous | ||
/ot_a4/f1_trk |
1 / 43 | 0–16256 | continuous | ||
/ot_a4/f1_dep |
1 / 44 | 0–16256 | continuous | ||
/ot_a4/reverb |
1 / 57 | 1024–16256 | continuous | ||
/ot_a4/f2_frq |
1 / 45 | 0–16383 | continuous | ||
/ot_a4/f2_res |
1 / 46 | 0–16256 | continuous | ||
/ot_a4/f2_trk |
1 / 48 | 0–16256 | continuous | ||
/ot_a4/f2_dep |
1 / 49 | 0–16256 | continuous | ||
/ot_a4/delay |
1 / 56 | 0–16256 | continuous | ||
/ot_a4/f1_frq |
1 / 40 | 0–16383 | continuous | ||
/ot_a4/f1_res |
1 / 41 | 0–16256 | continuous | ||
/ot_a4/f1_ovr |
1 / 42 | 0–16256 | continuous | ||
/ot_a4/f1_trk |
1 / 43 | 0–16256 | continuous | ||
/ot_a4/f1_dep |
1 / 44 | 0–16256 | continuous | ||
/ot_a4/reverb |
1 / 57 | 1024–16256 | continuous | ||
/ot_a4/f2_frq |
1 / 45 | 0–16383 | continuous | ||
/ot_a4/f2_res |
1 / 46 | 0–16256 | continuous | ||
/ot_a4/f2_trk |
1 / 48 | 0–16256 | continuous | ||
/ot_a4/f2_dep |
1 / 49 | 0–16256 | continuous | ||
/ot_a4/delay |
1 / 56 | 0–16256 | continuous | ||
/ot_a4/f1_frq |
1 / 40 | 0–16383 | continuous | ||
/ot_a4/f1_res |
1 / 41 | 0–16256 | continuous | ||
/ot_a4/f1_ovr |
1 / 42 | 0–16256 | continuous | ||
/ot_a4/f1_trk |
1 / 43 | 0–16256 | continuous | ||
/ot_a4/f1_dep |
1 / 44 | 0–16256 | continuous | ||
/ot_a4/reverb |
1 / 57 | 1024–16256 | continuous | ||
/ot_a4/f2_frq |
1 / 45 | 0–16383 | continuous | ||
/ot_a4/f2_res |
1 / 46 | 0–16256 | continuous | ||
/ot_a4/f2_trk |
1 / 48 | 0–16256 | continuous | ||
/ot_a4/f2_dep |
1 / 49 | 0–16256 | continuous | ||
/ot_a4/delay |
1 / 56 | 0–16256 | continuous |
Performance MIDI¶
Notes, pitch bend and any CC are also available: /ot_a4/note/on <note> <velocity>, /ot_a4/cc/<number> <value>, /ot_a4/pitchbend <0-16383>, /ot_a4/program_change <n>.
Limitations¶
Imported from an Electra One community preset. The mapping reflects the preset author's editorial choices: parameter naming, ranges, and which params are exposed. Untested on hardware in this repo.
Frequently asked questions¶
How many parameters of the Elektron OT & A4 can be controlled over MIDI?
SynthHub's map of the Elektron OT & A4 lists 36 MIDI CC and 33 NRPN parameters, each with its number, range and a readable name; the full chart is on this page.
Can an AI agent like Claude control the Elektron OT & A4?
Yes: SynthHub's hosted MCP server knows the Elektron OT & A4's MIDI map, and its browser relay lets the agent send it parameter changes or load a sound, each sound change confirmed by you.