The Westerlund One is a preamp, overdrive and boost pedal in one box, and it was the first pedal released by the Oklahoma-based builder Westerlund1. Rather than a traditional overdrive stompbox, it is designed, in Delicious Audio's words, "less like a traditional stompbox and more like a high-end studio preamp for your instrument"2. The circuit is built around three FET-based op-amp gain stages and a FET tone recovery stage, a design the launch coverage credited with "a very tube-like tone and feel"1.
The pedal is built around three FET-based opamp gain stages and a FET tone recovery stage, which Delicious Audio says lend to "a very tube-like tone and feel"13. Depending on how you set it, the maker describes it as covering "a pristine, high-headroom line driver, a touch-sensitive overdrive, or a roaring preamp to punish the front end of your amp"2.
A FET preamp, overdrive and boost
The One combines three functions. As a preamp it offers plenty of headroom3. As an overdrive, its FET gain stages can be pushed into touch-sensitive breakup2. And as a boost, it carries an independent, adjustable boost circuit that sits before the gain stage, with its own level knob and footswitch21.
That pre-gain placement matters for how the boost behaves. Because it feeds the gain stages rather than sitting after them, the boost works together with the overdrive: Pedal of the Day describes going "from a subtle volume increase to pushing the sound into amp-like saturation and compression"3. Pedal of the Day echoed the same point, calling the pedal "a high-end preamp for your instrument" with "a gain boost, a 3-band EQ, and plenty of headroom"3.
The controls
Guitar Pedal X's review lists the full control set4:
| Control | Function |
|---|---|
| Gain | Sets the amount of drive from the FET gain stages |
| Level | Sets the output volume |
| Bass, Middle, Treble | 3-band EQ, described by Delicious Audio as "a musical and responsive EQ"1 |
| Boost | Sets the amount of pre-gain boost, with its own level knob and footswitch1 |
| Clipping switch | Hard/Soft or no clipping, plus Ge/Si diode selection41 |
| Core Voicing switch | Bright or Dark4 |
There are two footswitches: an Engage/Bypass switch for the main circuit and a separate Boost footswitch4. The Bright/Dark core voicing switch gives additional tonal flexibility, with Bright mode intended for normal operation1. Guitar Pedal X's reviewer found it genuinely useful:
"The Bright/Dark switch is really clever - to allow you to quickly adapt the Preamp to your own Rig"
Clipping modes: Amp Mode, germanium and silicon
The One offers five FET-based clipping modes, obtained through a combination of switches1. A 3-way switch sets Hard clipping, Soft clipping, or no clipping, and a 2-way switch selects Silicon or Germanium diodes1. Guitar Pedal X summarizes the options as "4 Clipping Options - Hard or Soft Ge or Si" plus the clipping-off mode4.
The three basic modes are1:
- Amp Mode (clipping off): no diode clipping at all, leaving the FET gain stages to shape the tone on their own1
- Germanium (GE) clipping: hard or soft clipping through germanium diodes1
- Silicon (SI) clipping: hard or soft clipping through silicon diodes1
Amp Mode is the setting that most separates the One from a conventional overdrive. With clipping disengaged, the pedal works as a clean, high-headroom FET preamp, and the diode options then let you dial in the character and intensity of the dirt on top of that21.
Does the Westerlund One use op-amps?
Yes, but not in the usual way. The gain stages are op-amp circuits built from FETs (field-effect transistors) rather than op-amp IC chips. Delicious Audio describes the topology as "three unique FET-based op-amp gain stages and a FET tone recovery stage"2. Both the launch coverage and Pedal of the Day credited this design with the pedal's tube-like tone and feel31, and Delicious Audio's later product page describes the result as "a remarkably authentic, tube-like feel with massive headroom and exceptional touch sensitivity"2.
Who makes it, and who plays it
The Westerlund One is made by Westerlund, a young Oklahoma-based builder, and it was the company's first pedal release1. Guitar Pedal X describes it as "the first pedal from the partnership of Matt Stansberry, Shane Henry, and Jim Robinson"4.
On the player side, Pedal of the Day reported in July 2023 that "Vince Gill was Westerlund's first customer and it's currently on his pedalboard"3.
Delicious Audio noted at launch that the pedal's high-end components and top-notch tone come with "a higher-than-average price tag"1, and Pedal of the Day described it as "this options-laden mammoth" that can give your signal a pop3.
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Questions
Does Vince Gill use the Westerlund One?
Yes. Pedal of the Day reported in July 2023 that Vince Gill was Westerlund's first customer and that the pedal was on his pedalboard at the time. It is the only documented player named with the pedal in the coverage of its launch.
What does Amp Mode do on the Westerlund One?
Amp Mode is the pedal's clipping-off setting. With the clipping switch set to off, no diode clipping is applied and the FET gain stages do the work on their own, which is why Westerlund labels it Amp Mode. It sits alongside the Germanium and Silicon clipping options on the same switch.
Does the Westerlund One use op-amps?
Yes, but not conventional op-amp chips. The circuit is built around three FET-based op-amp gain stages and a FET tone recovery stage, meaning the gain stages are constructed from field-effect transistors rather than standard IC op-amps. Reviewers credited this design with the pedal's tube-like tone and feel.
What does the Bright/Dark switch do on the Westerlund One?
It is a core voicing switch that shifts the pedal's overall tonal balance. Bright mode is described as the normal operating position, while Dark dials the top end back. Guitar Pedal X called it a clever way to quickly adapt the preamp to your own rig.
Who makes the Westerlund One pedal?
Westerlund, an Oklahoma-based builder. The One was the company's first pedal release, and Guitar Pedal X describes it as the first pedal from the partnership of Matt Stansberry, Shane Henry and Jim Robinson.
Sources (4)
- New Pedal: Westerlund One Preamp, Delicious Audio, 2023-07-13
- Westerlund One Preamp, Delicious Audio, 2026-09-23
- Westerlund Audio ONE Preamp Overdrive Boost, Pedal of the Day, 2023-07-29
- Guitar Pedal X, Guitar Pedal X, 2023-11-02
