The SunnAudio NU-1 Nucleus is a compact two-channel analog preamp pedal with distortion and overdrive functions, released by Sunnaudio of Belmont, California on 12 October 20201. Sunnaudio describes it as a "Dual Boost Preamp Distortion"2, and the company positions it as a no-fuss preamp that goes from clean to full distortion1. It is built for electric and bass guitars and also works with most passive or active acoustic guitar pickups3.
The core of the pedal is its two switchable gain channels, HI Gain and LO Gain, each with an independently settable output level1. The LO channel ranges from crystal clear tones to a nice overdriven breakup, while the HI channel goes from rich clean tones to full saturated grind1. One Gain knob, shared by both channels, adjusts the drive from pure clean to overdrive on the fly13.
What it does: a two-channel clean to high-gain preamp
The Nucleus is a dual Hi and Lo output preamp distortion overdrive with dual boost function4. Gearnews reported that, according to the manufacturer, the two-channel preamp goes from "pure clean" to full-on, high-gain overdrive5. Guitar World described it as an all-analog integrative preamp and overdrive promising "harmonically rich saturated sounds"6.
The two channels are the main draw. Each has its own level control, so a player can set the LO channel to sit under a rhythm part and the HI channel to kick above the rest of the mix for a solo, or match a lower-gain part to a high-gain tone7. Each channel gets its own LED knob indicating which channel is selected1. The HI gain boost control can add up to 60dB of gain5.
The enclosure fits in a standard Hammond-sized space on a pedalboard1, and the oversized footswitch covers come in red, blue, and green6.
The controls
| Control | What it does |
|---|---|
| Gain | One shared knob, pure clean to overdrive, described as deceptively sophisticated4 |
| Level (per channel) | Independent output level for HI and LO channels1 |
| Tone | Mid shaping of the overdrives4 |
| Focus | Adjusts sub-harmonic frequencies for bass, or contours an overdriven guitar sound4 |
| Hi/Lo Gain footswitch | Switches between the two gain channels4 |
| Bypass footswitch | True bypass on/off4 |
There is also an internal input impedance switch for optimum matching between instruments3. Pedal of the Day's reviewer found that the Tone and Focus controls, along with the differing levels of gain, open up the sonic possibilities on both guitar and bass3.
Power and connections
The Nucleus is powered by a 7.5V to 12V external DC adapter or a 9V battery1. The battery offers more than 80 hours of typical life4. Because the circuit is pure analog, varying the external DC jack voltage (7.5V to 12V DC maximum) alters the harmonic characteristics of the pedal, so the supply voltage is itself a tone control of sorts34.
The DC jack voltage range is reported as 7.5V to 12V DC in the Pedal of the Day review34, while Delicious Audio lists 3V to 12V DC maximum4. The pedal can also run on a 9V battery4.
The pedal has a TRS balanced output1, which Gearnews highlighted as a feature for running into mixers, interfaces, or PA systems as well as conventional amps5. An internal input impedance switch helps match passive and active pickups, including acoustic pickups35.
Where it came from and what players said
Sunnaudio released the Nucleus NU-1 on 12 October 20201. Lead engineer Sunny Wai and senior product developer Marc Games worked on the high-gain preamp design1. Each pedal is built to order5, and the preamps are made in small batches3.
Players named in the launch include Jude Gold, host of the No Guitar Is Safe podcast and lead guitarist of Jefferson Starship1.
"Really great tone! I'm really enjoying the Nucleus, two great sounds in one small footprint, which not all of my dual mode pedals can say."
"Regardless of what bass rig I'm playing through, I can go from a throbbing dub tone to a ripping punk vibe that cuts."
Pedal of the Day reviewed the pedal on 24 November 2020 with demos on both guitar and bass, concluding:
"When it comes down to it, this thing just rips."
Videos
Sunnaudio .com
EytschPi42
Perfecto De Castro
News
Questions
Does the SunnAudio Nucleus work with bass guitar?
Yes. The NU-1 Nucleus was designed for electric and bass guitars, and its Focus control adjusts sub-harmonic frequencies in the bass signal. Bassist Pete Canton said that regardless of the rig he plays through, he can go from a throbbing dub tone to a ripping punk vibe that cuts through the mix.
Can I use the NU-1 Nucleus with an acoustic guitar pickup?
Yes. The pedal works with most passive or active acoustic guitar pickups, and it has an internal input impedance switch for optimum matching between instruments. Gearnews noted it can handle both passive and active acoustic pickups.
Does changing the power voltage change the sound of the Nucleus?
Yes. The circuit is pure analog, and varying the external DC jack voltage alters the harmonic characteristics of the pedal. The DC jack accepts 7.5V to 12V DC maximum, so a player can experiment within that range for different harmonic textures.
How long does a battery last in the NU-1 Nucleus?
The pedal runs on a 9V battery with a typical life of more than 80 hours. It can also be powered through the external DC jack at 7.5V to 12V DC, so battery use is an option for players who want to travel light.
Is the SunnAudio NU-1 Nucleus true bypass?
Yes. The pedal has two footswitches, one for switching between the Hi and Lo gain channels and one for true bypass, so the signal passes through untouched when the pedal is off.
How much gain does the HI channel add?
The HI gain boost control can add up to 60dB of gain. The HI channel itself ranges from rich clean harmonic sounds to full distortion, while the LO channel ranges from crystal clear to overdrive.
Sources (7)
- Sunnaudio Nucleus NU-1: New Dual Boost Distortion, Premier Guitar, 2020-10-12
- Sunnaudio's Nucleus NU-1 is dual boost preamp with two flavours of drive on tap, MusicRadar, 2020-10-19
- Sunnaudio NU-1 Nucleus Preamp, Pedal of the Day, 2020-11-24
- Sunnaudio NU-1 Nucleus Two-Channel Preamp/Overdrive, Delicious Audio, 2022-01-04
- SunnAudio NU-1 Nucleus: an analogue preamp/distortion pedal, gearnews.com, 2020-10-13
- Sunnaudio goes big with the Nucleus NU-1 dual boost preamp, Guitar World, 2020-10-20
- Sunnaudio’s Nucleus NU-1 preamp pedal ranges from crystal cleans to high gain, Guitar.com, 2020-10-13