The Fractal Audio AM4 is a compact, pedalboard-ready amp modeler that brings Axe-Fx III-caliber amp modeling, speaker simulation and effects into a floor unit the size of a large pedal12. Fractal announced it on November 25, 2025 as its most compact all-in-one amp modeler, built on the same technology as the rack-mounted Axe-Fx III, and it is now shipping in the USA and Canada at a list price of $69913.
Fractal describes the AM4 as delivering "the tone, feel, and authentic controls of real tube amps," from vintage classics to modern high-gain designs, through its latest Cygnus X-3 amp modeling, visual DynaCab speaker simulation and UltraRes user cabs1. Guitar World's buying guide counts 240+ amps and 325+ effects onboard4.
Axe-Fx III modeling in a pedalboard unit
The AM4's amp tones use the same Cygnus X-3 engine as the Axe-Fx III, Fractal's flagship rack preamp4. MusicRadar's reviewer Trevor Curwen framed it as "Axe-FX III algorithms in a compact format," the essential pitch of the product: rack-grade modeling in a box that sits on a pedalboard or a studio desk5.
The unit holds 104 customizable presets, organized in 26 banks of four, with each preset containing four blocks and four scenes15. That gives a player a lot of sounds reachable from the footswitches without diving into menus.
Four footswitches, five modes
The front panel carries four footswitches that work in five modes: Presets, Scenes, Effects and effect channels, Tuner/Tempo, and Amp Mode, with custom colors for the switches1. MusicRadar identifies the three primary modes as Preset, Scene and Effects, plus an Amp mode that assigns each amp block channel its own footswitch5.
| Mode | What it does |
|---|---|
| Preset | Footswitches select four presets6 |
| Scene | Access scenes within a preset5 |
| Effects | Switch effects and effect channels on and off1 |
| Tuner / Tempo | Tuner and tempo functions1 |
| Amp | Each footswitch selects an amp block channel5 |
Controls on top are a Level knob, a Select knob, four soft knobs (A, B, C, D), six buttons and the four footswitches5. Two Pedal ports on the back each accept an expression pedal or an external footswitch, so up to two expression pedals can be connected for real-time control of effects15.
Power and connections
The AM4 is powered by the included 9V DC 1.5A adapter, through a center-negative DC barrel jack16. A Walrus Audio Canvas Power review measured its draw at 1.3A while noting it requires a 1.5A supply, which rules out sharing a typical isolated daisy chain with other pedals7.
At 1.3A actual draw and a 1.5A supply requirement, the AM4 needs most of a power supply's output to itself. Plan a dedicated 9V output rated for at least 1.5A7.
The I/O is what Fractal calls pro-grade: a low-noise Auto-Z instrument input, balanced TRS outputs, a stereo analog insert (Send and Return), S/PDIF I/O, and MIDI via USB-C plus 3.5mm MIDI In and Out15. There is also a 1/8" headphone output5.
| Connection | Detail |
|---|---|
| Input | Low-noise Auto-Z instrument input1 |
| Outputs | Balanced TRS L (mono) and R15 |
| Insert | Stereo analog Send and Return15 |
| Digital | S/PDIF In and Out15 |
| USB | USB-C for MIDI and 4x4 audio with re-amping1 |
| MIDI | 3.5mm MIDI In and Out1 |
| Pedal | Two ports, expression pedal or footswitch each1 |
| Headphones | 1/8" output5 |
The 4x4 USB audio with re-amping means the AM4 doubles as a 4-in/4-out recording interface. MusicRadar's reviewer took advantage of that ability to function as an audio interface, and Fractal notes you can play computer audio back through the AM4's stereo outputs15.
How it differs from the VP4
The AM4 shares its four-footswitch form factor and its price point with Fractal's VP4 Virtual Pedalboard, but where the VP4 has no amp modeling, the AM4 adds it5. The VP4, launched in October 2024, is a multi-effects unit built from Axe-Fx III effect models with hundreds of effects and classic on/off footswitch switching89. In short: a player who already has an amp and wants effects chooses the VP4; a player who wants the amp chain in the same box chooses the AM4.
Build and hardware
The AM4 sits in a sturdy brushed-aluminum chassis with a slanted area for the footswitches, sized for gigging6. It measures 255mm x 160mm x 59mm and weighs 1.63kg6.
"As far as build quality goes, it really is flawless."
Firmware and documentation
Fractal publishes documentation for the AM4 as PDF downloads: an Owner's Manual version 1.x, dated November 24, 2025, and a Quick Start Guide10. Both are available from the AM4 downloads page.
Videos
Fractal Audio and 2 more
Ola Englund
Leon Todd
Questions
How many amp models and effects does the Fractal AM4 have?
Guitar World's buying guide lists the AM4 with 240+ amp models and 325+ effects. The amps use Fractal's Cygnus X-3 modeling, the same engine as the Axe-Fx III, alongside DynaCab speaker simulation and UltraRes user cabs.
Can the AM4 be used as a USB audio interface for recording?
Yes. The AM4 offers 4x4 USB audio with re-amping over its USB-C port, so it functions as a 4-in/4-out audio interface. MusicRadar's reviewer used it this way, and you can play computer audio back through the AM4's stereo outputs.
Does the Fractal AM4 work with an expression pedal?
Yes. Two Pedal ports on the back each accept an expression pedal or an external footswitch, so you can connect up to two expression pedals for real-time control of effects.
How many presets does the AM4 hold?
The AM4 holds 104 customizable presets, organized in 26 banks of four. Each preset contains four blocks and four scenes, and Preset mode gives the four footswitches instant access to four presets at a time.
Is the AM4 the same modeling as the Axe-Fx III?
Yes. Fractal builds the AM4 on the same technology as the Axe-Fx III, and MusicRadar describes it as Axe-Fx III algorithms in a compact format. The amp tones use the same Cygnus X-3 engine as the Axe-Fx III.
Sources (10)
- AM4 Amp Modeler, Fractal Audio, 2026-08-06
- About Us, Fractal Audio Systems, 2025-11
- Fractal AM4 amp modeler takes on IK Multimedia and Line 6, Guitar World, 2025-11-25
- Best multi-effects pedals 2026: replace your rig, Guitar World (www.guitarworld.com), 2022-08-25
- Fractal Audio Systems FM4 review, MusicRadar, 2026-05-30
- Fractal AM4 review, guitarworld.com, 2026-02-02
- "It's currently the only compact power supply you can count on to power a 3A, 12V amp and effects modeller alongside pedals without buying any extra kit": Walrus Audio Canvas Power HP review, MusicRadar, 2026-03-25
- Fractal Audio VP4 review, Guitar World, 2025-01-13
- Fractal's new VP4 virtual pedalboard puts hundreds of classic stompbox and studio effect models at guitarists' feet in a compact and customizable unit, GuitarPlayer, 2024-10-15
- AM4 Downloads, Presets, Manual, Drivers, Fractal Audio Systems, 2026-09-15
