The One is a preamp pedal from Colombo Audio, announced in April 2025 as an analog high-gain preamp inspired by the Marshall JMP-1 rack preamp. Rather than a direct clone, the circuit reimagines the JMP-1's signature tones, with the stated aim of making those tones accessible without complex setups. Delicious Audio's Paolo De Gregorio describes it as "a simple, analog pedal" that delivers "vintage-voiced high gain with studio-grade EQ flexibility"1.
How it sounds and how it works
Colombo Audio builds The One on hybrid op-amp/JFET circuitry, which the maker says delivers tube-like dynamics and response1. In plain terms, that means the gain stages use an op-amp for the heavy lifting and JFET transistors to shape the feel, an approach common in pedals that chase the touch and compression of a pushed tube preamp while staying fully analog1.
The pedal's voice centers on the JMP-1 heritage: high gain with a midrange character that can be tuned rather than fixed. Where a straight clone would lock you into one mid frequency, The One gives you two lead voices and a tone section that reaches beyond a normal treble and bass pair1.
Lead 1, Lead 2 and the tone controls
The One's controls split into two lead modes and a tone section:
| Control | What it does |
|---|---|
| Lead 1 | Warm, sharp mids centered at 800Hz1 |
| Lead 2 | Airy, vocal-like mids centered at 1kHz1 |
| Middle | Sculpts midrange character: neutral at noon, scooped when lowered, thickened when raised1 |
| Tone | Behaves like a parametric EQ, offering nuanced shaping beyond standard treble/bass adjustments1 |
The two lead modes are the heart of the pedal. Lead 1 sits the midrange at 800Hz for a warmer, sharper bite, while Lead 2 moves the focus up to 1kHz for a more open, vocal quality. Between them and the parametric-style Tone control, a player can dial the pedal into different amps and cabinets without giving up the core high-gain character1.
"Middle control sculpts midrange character, neutral at noon, scooped when lowered, or thickened when raised."
Where it sits on a board
As a preamp, The One is built to be a tonal foundation rather than a one-trick boost: it can drive an amp's return, act as a second channel for a clean amp, or simply push a pedal platform into high-gain territory. Because it is true bypass, it stays out of the signal path when disengaged, which Delicious Audio describes as keeping "transparent signal integrity when disengaged"1. Players comparing preamp options can see how other circuits approach the same job on the Preamp Pedals page.
Videos
Brett Kingman
Luca Colombo
Eddie Clark
Questions
Is the Colombo Audio The One true bypass?
Yes. Delicious Audio reports that The One is true bypass, so when the pedal is disengaged the signal passes through without the circuit loading it. For a preamp that players may run as a always-on foundation of a rig, that also means it can sit on a board and be switched in only for lead parts without coloring the clean signal in between.
Is The One a clone of the Marshall JMP-1?
No, not according to Delicious Audio, which describes the circuit as a reimagining rather than a direct clone of the JMP-1's signature tones. The aim, as reported, is to make the JMP-1's iconic tones accessible in pedal form without complex setups, rather than to reproduce the rack unit component for component.
Is the Colombo Audio The One analog or digital?
The One is an analog pedal. Delicious Audio describes it as a simple, analog pedal built around hybrid op-amp/JFET circuitry, which the maker says delivers tube-like dynamics and response. There is no modeling or digital processing involved in the gain or tone stages.
What is the difference between Lead 1 and Lead 2 on The One?
The One offers two distinct lead modes. Lead 1 delivers warm, sharp mids centered at 800Hz, while Lead 2 moves the mid focus up to 1kHz for an airy, vocal-like character. Switching between them changes where the midrange sits, which is the core of how the pedal's high-gain voice is shaped.
Sources (1)
- New Pedal: Colombo Audio The One, Delicious Audio, 2025-04-28