Every connector is on the rear panel and the front panel carries two LEDs. This chapter names each one, says what plugs into it, and shows four common ways to wire NEXUS.
Front panel
The front panel has no controls. Everything is set from Omnissiah, or from a MIDI or OSC controller through Omnissiah.
STATUS LED
| STATUS | Meaning |
|---|---|
| Red | NEXUS is starting up. Normal for a few seconds after power is applied. |
| White | Ready. NEXUS is running and passing audio. |
| Yellow | A fault during start-up. See Chapter 9 — Troubleshooting. |
| Red, and never turns white | Start-up failed. NEXUS returns to its previous firmware and restarts. |
| Three quick flashes | Omnissiah's Identify button, so you can see which unit the app is talking to. |
SIGNAL LED
The SIGNAL LED flashes green with the audio leaving NEXUS, whichever source it comes from. The LED stays dark when the output is below -60 dBFS, which covers silence and very quiet passages. The LED turns red while an output is clipping. If you see red, turn the source down or reduce the gain on that output (Chapter 8 — Outputs & crossovers).
Rear panel
From left to right:
| Label | Connector | What it is for |
|---|---|---|
| 5V ⎓ 2A | USB-C | Power only. Use it when NEXUS runs without a computer: any USB-C supply rated 5 V, 2 A. |
| UAC | USB-C | The computer connection. One cable carries audio, control and power. |
| Func | Button | [TBC: user function, if any.] |
| Output 3 | 6.35 mm TRS jack, balanced | One channel: a subwoofer, a mono speaker or a utility feed. +18 dBu maximum. |
| Output 1-2 | Two 6.35 mm TRS jacks, balanced | The stereo pair, normally your left and right monitors. +18 dBu maximum. |
| Aux In | 3.5 mm stereo jack | Line level, for a phone or a portable player. |
| Input 1-2 | Two 6.35 mm TRS jacks, balanced | Two analogue line inputs. +20 dBu maximum. |
| S/PDIF | RCA (coaxial) | Digital input, up to 96 kHz. |
In each stacked pair, [TBC: whether the upper jack is 1 or 2].
[TBC: whether unbalanced TS jack leads are safe on the outputs.]
Powering NEXUS
- With a computer: connect the UAC port to the computer with the supplied USB-C cable. The computer powers NEXUS, and nothing goes in the 5V port.
- Without a computer: after setup, plug a USB-C supply rated 5 V, 2 A into the 5V ⎓ 2A port. NEXUS keeps every setting, including the room correction.
NEXUS starts whenever power arrives. NEXUS has no power switch.
Inputs
- Input 1-2 takes balanced line level, up to +20 dBu: a mixer, an audio interface's line outputs, a synth, a streamer's analogue outputs.
- Aux In takes a consumer stereo source on a 3.5 mm jack.
- S/PDIF takes PCM stereo from a CD transport, streamer, TV or interface at up to 96 kHz. NEXUS mutes the S/PDIF input while it has no lock or when the source sends compressed surround (Dolby or DTS), so set the source to PCM or stereo output.
- USB audio arrives over the UAC cable. NEXUS appears on the computer as an audio device called Tantrum Nexus, with no driver to install.
The USB and S/PDIF inputs reach the routing matrix together as one pair, called Digital. Each has its own level and mute. Chapter 7 — Routing & sources covers the matrix.
Outputs
Connect powered monitors, or a power amplifier, directly to the outputs.
- Output 1-2: left and right speakers.
- Output 3: a subwoofer. Without a sub, Output 3 can feed a mono speaker for mono checks, or any other single-channel destination.
Warning
Turn your speakers or amplifier down before connecting or disconnecting an output lead. A plug going into a live output sends a loud click to the speaker.
Wiring examples
Source switching with a subwoofer
Four sources in, a stereo pair on Output 1-2 and a sub on Output 3. One source is live at a time.
A/B between two sets of speakers
Your main pair on Output 1-2, a mono reference speaker on Output 3, and a MIDI or OSC button pad switching between them through Omnissiah.
Hi-fi without a computer
Streamer, turntable preamp and phone in, power amplifier out, powered from a USB-C charger. The laptop is only needed for setup.
Travel rig
A laptop playing over USB audio into NEXUS, powered from the same cable, with a stored correction for each room you work in.
