The O2 Oxygen is a bass preamp pedal from Nemphasis, announced at NAMM and reported as available to buy as of February 2016. It came in two versions: the Pro Series O2 Oxygen and the regular O2 Oxygen. MusicRadar reported UK prices of £189 and £149 respectively at announcement1.
The two versions
The Pro Series model is the fuller-featured of the two. MusicRadar described it as packing a three-band EQ section with a mode footswitch, which lifts the pedal's EQ and volume for solos and highlighting noteworthy runs. It also carries an XLR output that delivers a balanced DI out, so the preamp's signal can go straight to a mixing desk or interface1.
The regular O2 offers the same functionality as its bigger brother, but does away with the DI out and switchable modes while adding a toggle switch for preset mid boost or cut1.
| Pro Series O2 Oxygen | Regular O2 Oxygen | |
|---|---|---|
| Three-band EQ | Yes, with mode footswitch | Same functionality1 |
| Mode footswitch (EQ and volume lift) | Yes1 | No1 |
| Balanced XLR DI out | Yes1 | No1 |
| Preset mid boost or cut toggle | Not reported | Yes1 |
| UK price at announcement | £1891 | £1491 |
Controls and outputs on the Pro Series model
The Pro Series O2 Oxygen's controls cover the input stage, the tone shaping and the connections to the rest of a rig:
- Gain control and input level: cater for passive and active basses, so the pedal can be set to suit either kind of instrument1
- Three-band EQ: the pedal's main tone shaping section1
- Mode footswitch: lifts the pedal's EQ and volume for solos and highlighting noteworthy runs1
- XLR output: delivers a balanced DI out1
- Ground lift switch: gets rid of earth loops1
The ground lift switch matters when the DI out is in use: earth loops between a bass rig and other grounded equipment are a common cause of hum, and lifting the ground is the usual remedy1.
Power
MusicRadar reported that the O2 Oxygen pedals can be powered by standard 9V power supplies1. Both the O2 Oxygen Bass Preamp and the Pro Series version were officially announced at NAMM and are available to buy1.
Videos
Marco Sassetti
Bassline Music Shop
Simone Masina
Questions
Does the Nemphasis O2 Oxygen have a DI output?
The Pro Series O2 Oxygen does: MusicRadar reports that an XLR output delivers a balanced DI out on that model. The regular O2 does away with the DI out, so if you need to run a balanced line to a mixing desk or audio interface from the pedal itself, the Pro Series is the version with that connection.
What power does the Nemphasis O2 Oxygen use?
According to MusicRadar, the O2 Oxygen pedals can be powered by standard 9V power supplies, so they fit a conventional pedalboard power setup rather than needing a dedicated supply.
Does the O2 Oxygen work with both passive and active basses?
Yes. On the Pro Series model, MusicRadar reports that a gain control and input level cater for passive and active basses, meaning the input stage can be set to suit the output level of either kind of instrument.
What does the ground lift switch do on the Nemphasis preamp?
MusicRadar reports that the Pro Series O2 Oxygen carries a ground lift switch that gets rid of earth loops. Earth loops are a common cause of hum when a bass rig is connected to other grounded equipment, and lifting the ground on the DI connection is the usual fix.
Sources (1)
- Nemphasis breathes new life into bass preamps with O2 Oxygen pedals, MusicRadar, 2016-02-24
