The Nemphasis Pro Series O2 Oxygen is a bass preamp pedal announced at NAMM and available as of February 2016. It sits between your bass and the rest of your rig, shaping tone with a three-band EQ and feeding a balanced DI signal to a desk or PA through its XLR output1. Nemphasis launched it alongside a regular O2 Oxygen Bass Preamp, a less expensive sibling in the same announcement1.
Controls and what they do
The pedal's controls cover input matching, tone shaping and a solo lift:
| Control | What it does |
|---|---|
| Gain control | Sets drive into the preamp; caters for passive and active basses1 |
| Input level | Matches the pedal to passive or active instrument output1 |
| Three-band EQ | Shapes bass, mid and treble1 |
| Mode footswitch | Lifts the pedal's EQ and volume for solos and highlighting noteworthy runs1 |
| Ground lift switch | Gets rid of earth loops1 |
The mode footswitch is the pedal's performance feature: you step on it to bring in a lifted EQ and volume setting when a part needs to cut through, then step off to return to your normal sound1.
The ground lift switch matters most when you use the XLR DI output. If your amp rig and the desk both earth the signal, an earth loop can cause hum; lifting the ground on the DI path removes it1.
Power and setup
The O2 Oxygen runs on standard 9V power supplies, so it takes its place on a pedalboard alongside other common pedals without special power requirements1. Inside the pedal, an internal bass boost adjustment offers extra low-end for players who want more weight than the front-panel EQ provides1.
The Pro Series and the regular O2
Nemphasis announced two versions at NAMM: this Pro Series O2 Oxygen at £189 and the regular O2 Oxygen Bass Preamp, both announced as officially available to buy1. For more on where a preamp like this fits on a board, see Bass Pedals.
Videos
Bassline Music Shop
Marco Sassetti
Bassline Music Shop
Questions
Does the Nemphasis O2 Oxygen have an XLR output?
Yes. The Pro Series O2 Oxygen carries an XLR output that delivers a balanced DI out, so the pedal can feed a mixing desk or audio interface directly without a microphone on your cabinet. MusicRadar's announcement of the pedal notes the XLR output alongside the pedal's gain, input level and EQ controls.
Does the O2 Oxygen work with passive and active basses?
Yes. The pedal has a gain control and an input level control, and MusicRadar describes these as catering for passive and active basses. The input level lets you match the pedal to the hotter output of an active instrument or the lower output of a passive one before the gain stage.
What does the ground lift switch do?
The ground lift switch gets rid of earth loops. An earth loop happens when your bass rig and the PA or recording setup are both earthed through different paths, which can produce hum. Lifting the ground on the DI output breaks that loop and quiets the noise.
What does the mode footswitch do on the Nemphasis O2 Oxygen?
The mode footswitch lifts the pedal's EQ and volume settings for solos and for highlighting noteworthy runs. In practice you set a second, louder or differently voiced EQ preset, and stepping on the footswitch brings that setting in for as long as you want to stand out.
What power does the Nemphasis O2 Oxygen need?
The pedal can be powered by standard 9V power supplies, according to MusicRadar's announcement. That means it fits alongside typical pedals on a board without a special supply.
Sources (1)
- Nemphasis breathes new life into bass preamps with O2 Oxygen pedals, MusicRadar, 2016-02-24
