The Cornerstone Nucleo is a stereo ambient reverb pedal from Italian boutique pedal maker Cornerstone, designed in partnership with Dutch guitarist and YouTuber Paul Davids12. Its origin story is unusual: Davids visited the Zwentendorf nuclear power plant in Austria, and the pedal is inspired by the natural reverb of that disused plant, with microphone manufacturer Lewitt Audio creating an Impulse Response from recordings made there13.
Beyond traditional reverb, the Nucleo is built for cinematic textures and performative sound design, with pitch shifting, granular effects and a freeze function on board2. Pre-orders opened in October 2024 at a special launch price of $429, with the official launch slated for that December1.
Where it came from
The Nucleo began when Cornerstone's Emilio reached out to Paul Davids with an idea: capture the sound of a disused nuclear reactor and build a reverb pedal around it4. Davids had jammed inside the Zwentendorf plant in Austria, and Lewitt Audio, which organized the trip, created an Impulse Response from those recordings, forming the basis of the pedal's sound3.
"Amelio reached out to uh Paul and said, "Hey, why don't we do a river pedal where we capture that?""
A later version, the Nucleo 2, was priced at $449 as of December 2025 and features Room, Reactor and Hall modes, Freeze-Pitch, presets and Freeze5. Related pages cover the Cornerstone Nucleo Stereo Reverb, the Nucleo Power Station Hall Reverb and the Nucleo Power Station Reactor Hall Reverb.
The controls
The Nucleo delivers three core reverb modes: Reactor for dense reflections, Room for intimate spaces, and Hall for expansive decays2. Each can be customized with Voicing options: Normal, Vintage or Lo-Fi2. On the top panel, blend, decay and tone knobs create the basic reverb sound, with tone acting as the overall EQ of the reverb4.
| Control | What it does |
|---|---|
| Blend, Decay, Tone | Core reverb sound; tone is the reverb's overall EQ4 |
| Reactor dial | Sets reverb size, from a subtle lo-fi room effect to a massive, immersive soundscape1 |
| Modulation slider | Adjusts the amount and rate of modulation4 |
| Texture Shapers faders | MOD (modulation), ATR (pitch-shifting), FLUX (granular effects) for evolving soundscapes2 |
| Pre-delay | Secondary function on the bottom left knob, can be switched off4 |
| Footswitches | Bypass and Freeze1 |
The Reactor dial is the size control at the heart of the pedal's character. As guitar.com described it, it "allows you to manipulate the reverb size, ranging from a subtle lo-fi room effect to a massive, immersive soundscape"1.
Air and the Texture Shapers
Air is the Nucleo's pitch-shifting entrance into shimmer, with adjustable pitch4. It works alongside the three Texture Shapers faders, which control modulation, pitch-shifting and granular effects for evolving soundscapes2. Delicious Audio notes that beyond traditional reverb, the pedal "excels at cinematic textures and performative sound design"2.
Modes, presets and MIDI
A mode switch moves between three states: live mode, where all controls respond as labeled on the top panel; preset mode; and a middle mode that accesses secondary functions for each control, pre-delay among them4. Three presets live on the top panel, and MIDI expands that to 12824.
The pedal has full MIDI implementation with real-time control over parameters, useful for integrating it into a live rig14. Expression pedal control works via MIDI rather than a dedicated jack4. Outputs are transformer-isolated stereo, and the pedal doubles as a USB-C audio interface2.
What reviewers said
On That Pedal Show, Mick and Dan demoed the Nucleo in stereo alongside four other pedals, and later used it for the reverb duties in a full episode with both amp reverbs switched off46. Of its sound in a compact size, they judged the reverb quality spectacular:
"Sonically, it's it's really beautiful"
Guitar Pedal X's Stefan Karlsson reviewed the Nucleo favorably on usability as well as sound, writing that it "sounds wholly gorgeous all the time, is very intuitive and a genuine joy to deploy"5. In the site's 2025 delay and reverb awards, the Nucleo was "the clear winner from the start" of its category, praised for design, features and playability7. It was also named "the overwhelming winner for the Reverb category this year"8, ahead of the chasing pack.
In the That Pedal Show episode, the Nucleo Reverb sounds begin at 6:049. The hosts demo it in stereo, working through the blend, decay and tone controls, the modulation slider, the Air pitch shifting and the freeze function4.
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Questions
Who designed the Cornerstone Nucleo?
The Nucleo was designed in partnership between Italian boutique pedal maker Cornerstone and Dutch guitarist and YouTuber Paul Davids. The idea came about after Cornerstone's Emilio reached out to Davids about capturing the sound of a disused nuclear reactor, and microphone maker Lewitt Audio created an Impulse Response from recordings made in the plant.
What are the three reverb algorithms in the Nucleo?
The Nucleo offers three core reverb modes: Room for intimate spaces, Hall for expansive decays, and Reactor, which produces dense reflections and controls the reverb size, from a subtle lo-fi room effect to a massive, immersive soundscape. Each mode can be customized with Voicing options: Normal, Vintage or Lo-Fi.
Does the Cornerstone Nucleo have MIDI?
Yes. The Nucleo has full MIDI implementation with real-time control over parameters, which lets you integrate it into a live rig. Expression pedal control also works via MIDI rather than through a dedicated expression jack, and MIDI gives access to 128 presets.
What is the Air function on the Nucleo?
Air is the Nucleo's pitch-shifting entrance into shimmer, with adjustable pitch. It sits alongside the three Texture Shapers faders, which control modulation (MOD), pitch-shifting (ATR) and granular effects (FLUX) for evolving soundscapes.
How many presets can the Cornerstone Nucleo store?
Three presets are available on the top panel for quick access, and users can save their favourite settings into them. Connecting over MIDI expands that to 128 presets.
How much did the Cornerstone Nucleo cost at launch?
When pre-orders opened in October 2024, the Nucleo carried a special launch price of $429, with the official launch slated for that December. A later version, the Nucleo 2, was priced at $449 as of December 2025.
Sources (9)
- Meet Nucleo, the ambient reverb pedal inspired by a nuclear power plant, guitar.com, 2024-10-08
- New Pedal: Cornerstone Nucleo Stereo Reverb (Paul Davids Signature), Delicious Audio, 2025-07-29
- “Usually you hear it coming out of your amp. Here, you feel it all around you”: Paul Davids once visited a nuclear power plant to find the world's most incredible reverb, Guitar World, 2024-10-07
- So Much Tone! Mythos Big Puft, Cornerstone Nucleo, TWA Source Code, EHX Swello & Dinosaural Hypoid, That Pedal Show (YouTube), 2025-10-10
- Guitar Pedal X, Guitar Pedal X, 2025-12-11
- Pedals! Jam Wahcko Mk2, MXR Super Variac Fuzz, DevTech Evolve, Crazy Tube Circuits Rapture OD, That Pedal Show (YouTube), Oct 16, 20
- Guitar Pedal X, Guitar Pedal X, 2025-12-10
- Guitar Pedal X, Guitar Pedal X, 2025-11-11
- So Much Tone! Mythos Big Puft, Cornerstone Nucleo, TWA Source Code, EHX Swello & Dinosaural Hypoid, That Pedal Show, 2025-10-10
