The Fourth is a distortion pedal from Audio Cultivation Project, and the maker's fourth solid-state distortion design1. Delicious Audio's Paolo De Gregorio describes it as an overdrive/distortion pedal built to emulate the distortion produced by sought-after vintage solid-state amps of the '70s, naming the Music Man 112 RD, Epiphone Studio 10s and Silvertone 14642. Guitar Pedal X's Stefan Karlsson places it in brasher garage-punk and rock territory, sitting adjacent to those same amps1.
What it does
The circuit combines a hybrid transistor and op-amp design, blending hard clipping and op-amp saturation2. De Gregorio describes the pedal's character as its distinctive breakup, rich harmonic texture, and dynamic response to your playing2. He also notes that the Fourth was initially designed to deliver raw, trashy tones and has evolved into a highly versatile pedal2.
Controls
Guitar Pedal X describes the layout as starting with a fairly conventional control topology of Output/Level, Gain and Shape (bass EQ)1. On Delicious Audio's account, Shape is the Tone knob2.
| Control | What it does |
|---|---|
| Output / Level | Sets the pedal's output level1 |
| Gain | Sets the amount of drive1 |
| Shape | Bass EQ control; the Tone knob on Delicious Audio's description12 |
| Left toggle | 3-way gate: deactivated in the up position, extremely choked tones in the middle, partially gated ones in the lower position2 |
| Middle toggle | Delivers 3 bass EQ curves, preceding the gain stage2 |
| Right toggle | Offers 3 high-end EQ curve options2 |
Guitar Pedal X gives more detail on the two EQ toggles. The DARK toggle adjusts the treble response of the Fourth: middle for the brightest, flipped down for the darkest, and up for in-between. The CHOKE toggle creates a short in the circuit which accentuates the trashy decay: in the middle it is wide open, up gives the most choked, low-biased gated sounds, and down is slightly gated with buzzy decay1.
What reviewers said
"Something about its elegant design really appeals to me - as does its Drive / Distortion output profile."
Karlsson's review treats the Fourth as a strong take on trashier-sounding solid-state amps using a hybrid transistor and op-amp topology1. De Gregorio's product page frames it as a pedal that outgrew its raw, trashy origins to become highly versatile2.
Videos
The Audio Cultivation Project
collector//emitter
Strazburg
Questions
What does the Audio Cultivation Project Fourth sound like?
Delicious Audio's Paolo De Gregorio describes it as an overdrive/distortion pedal built to emulate the distortion of sought-after vintage solid-state amps of the '70s, such as the Music Man 112 RD, Epiphone Studio 10s and Silvertone 1464. Guitar Pedal X's Stefan Karlsson places it in a brasher garage-punk and rock territory, sitting adjacent to those same amps, with what the maker calls distinctive breakup, rich harmonic texture and dynamic response to playing.
What do the toggles on the Fourth do?
The left toggle is a 3-way gate: deactivated in the up position, extremely choked tones in the middle, and partially gated ones in the lower position. The middle toggle delivers three bass EQ curves ahead of the gain stage, and the right toggle offers three high-end EQ curve options. Guitar Pedal X describes the treble toggle as middle for brightest, down for darkest, and up for in-between.
Sources (2)
- Guitar Pedal X, Guitar Pedal X, 2025-03-11
- Audio Cultivation Project Fourth Distortion, Delicious Audio, 2025-02-24
