Fractal Audio Systems AM4

The Fractal Audio Systems AM4 is a compact amp modeler pedal that Fractal positions as a unit that works on a pedalboard or on a studio desk¹. It is now shipping in the USA and Canada¹. MusicRadar's review lists it at $699 in the US, with 104 presets onboard in 26 banks of four².

Where Fractal's VP4 Virtual Pedalboard is an effects processor with no amp modeling, the AM4 is the amp-focused sibling: same four-footswitch form factor, same price point, but with amp modeling where the VP4 has none². For players comparing multi-effects pedals, that split is the key difference between the two units.

What it does and how it sounds

The AM4 delivers what Fractal describes as real tube amp tone and feel through advanced physical modeling technology, with digital amp modeling and analog elements in the signal path¹. It includes a stereo room simulator alongside the amp and speaker simulation¹. Guitar World's buying guide notes that the amp tones use the same engine as those in the Axe-Fx III³.

Guitar World's reviewer Matt Lincoln found that shared lineage shows in the sound³⁴²:

He rated the sounds at four and a half stars⁴.

The controls and modes

The front panel carries a Level control, a Select control, four soft knobs (A, B, C, D), six buttons and four footswitches². The footswitches give instant access to Presets, Scenes, Effects and effect channels, Tuner/Tempo, and Amp Mode, with custom colors¹.

MusicRadar's Trevor Curwen describes three primary modes of operation, Preset, Scene and Effects, plus an Amp mode that assigns each amp block channel its own footswitch². Amp mode facilitates switching between four amps loaded into the amp block, with gapless changes between them⁴. Each preset also carries a tuner, tap tempo, a noise gate and EQ².

Two Pedal ports each accept an expression pedal or an external footswitch¹, and MusicRadar notes provision for up to two expression pedals for real-time control of effects².

Power and connections

The AM4 runs on the included 9V DC 1.5A adapter through a center-negative DC barrel jack¹⁴. MusicRadar lists the power requirement as a supplied 9V DC adaptor at 1500 mA². That draw is well above what a typical compact pedal supply offers, so plan on the included adapter or a suitably rated isolated output.

The I/O is what you would expect from a studio-capable unit rather than a simple stompbox¹²:

• Low-noise Auto-Z instrument input¹
• Balanced TRS outputs, L (mono) and R¹²
• Stereo analog insert (Send and Return)¹²
• 1/8" headphone output²
• S/PDIF In and Out¹²
• 3.5 mm MIDI In and Out¹
• USB-C for MIDI and 4x4 audio with re-amping¹

The USB-C port makes the AM4 work as an audio interface: you can record dry takes and re-amp them later through the amp block, and you can play back computer audio through the AM4's stereo outputs¹. MusicRadar also notes comprehensive MIDI capability for players who want to integrate it into a larger rig².

A sibling of the VP4 Virtual Pedalboard

The AM4 shares its four-footswitch form factor and its price point with the VP4, but where the VP4 has no amp modeling, the AM4 is built around it². Like the VP4, the AM4 is a compact pedalboard unit, and the VP4's firmware is upgradeable, a design approach Fractal carries across the family⁵¹. Both units are part of Fractal's current lineup, with the AM4 now shipping in the USA and Canada¹.

Build and what reviewers said

The AM4 sits in a sturdy, brushed-aluminum chassis with a slanted area for the footswitches, which Guitar World's reviewer judged ready to take on a busy gigging life⁴. MusicRadar's Trevor Curwen summed up the unit's place in Fractal's lineup:

His overall verdict was that it could grace any professional stage with its superb range of sounds, rugged build and great flexibility².

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