NU-X MG-400 Guitar Multi-FX Pedal

The NUX MG-400 is a powerful and affordable multi-effects modeler, designed as the bigger sibling to the popular MG-300. It features two high-performance DSP chips that deliver high-definition White-Box Amp Modeling (TS/AC-HD) along with Core-Image post-effects processing. Building on the success of the MG-300—known for its excellent sound, playability, and user-friendly interface—the MG-400 expands the feature set with movable signal blocks, 12 IR collection slots, a flexible Patch Level (P.L) block with MIN/MAX parameter settings, an expanded system menu, and a dedicated MASTER volume knob.

White-Box Amp Modeling

The MG-400 uses the same White-Box Amp Modeling algorithm found in the MG-300, making tone adjustments intuitive and natural. This technology combines White-Box amp modeling with pre-effects processing to deliver realistic response and playability.

Analog circuits behave unpredictably—adjusting one control can influence other parameters in subtle ways. This phenomenon, often described as “chaos inspiring creativity,” is part of what gives tube amplifiers their musical feel. Unlike traditional digital systems where parameters operate independently, the MG-400’s TS/AC-HD algorithm simulates real-time interaction between parameters, recreating the dynamic response guitarists expect from a real tube amp.

High-Resolution IR Processing

The MG-400 includes 512-sample impulse response (IR) resolution for detailed cabinet simulation. Each patch can load its own IR, and there are 12 additional IR Collection slots for extra storage.

Using the NUX QuickTone editor, users can also load third-party IR files (up to 48kHz sample rate). The MG-400 comes with:

• 25 guitar cabinet IRs (using four classic microphones and three mic positions)

• 8 bass cabinet IRs

• 3 acoustic guitar IRs

These options allow players to easily experiment with different cabinet sounds, play bass through the unit, or simulate acoustic tones with an electric guitar.

Flexible Signal Chain

The MG-400 features 10 independent and movable signal blocks:

NG • CMP • EFX • AMP • IR • EQ • MOD • DLY • RVB • P.L

These blocks can be freely rearranged either on the device or through the QuickTone editing software, allowing extensive customization of the signal chain. For example:

• Place the Patch Level block before the amp to create volume swells

• Move the Delay before the gain stage for rhythmic effects and textured riffs

Since Firmware v2.1.1, users can also swap certain blocks (CMP ↔ EFX, EFX ↔ MOD, MOD ↔ EFX, RVB ↔ DLY). This makes it possible to stack two delays, two compressors, or multiple drive effects simultaneously, expanding creative possibilities.

Intuitive Color Display

The MG-400 features a 2.8-inch 320×240 color LCD with a clear, intuitive interface. The simple layout makes it easy to navigate menus, adjust parameters, and create tones without constantly referring to a manual.

Scene Function for Live Performance

Each preset includes three SCENES, which act as snapshots within the same preset. By assigning CTRL1 or CTRL2 footswitches to the Scene function, players can instantly engage or bypass specific signal blocks.

This is especially useful for live performances, allowing quick transitions between tones while preserving delay and reverb trails when effects are turned off.

Jam Tools: Drum Machine & Looper

The MG-400 also includes built-in rhythm tracks and a phrase looper, making it ideal for practice, songwriting, and solo performance.

The NUX Phrase Loop Synchronization feature automatically matches your loop to the rhythm BPM.

Looping options:

• Stereo loop: up to 30 seconds

• Mono loop: up to 60 seconds

Recording modes:

• NR (Normal Recording): recording begins immediately when the LOOP footswitch is pressed

• AR (Auto Recording): recording starts automatically once the guitar signal is detected

QuickTone™ Editor Software

The QuickTone™ editor provides a convenient way to manage and edit your MG-400 from a computer. With its intuitive interface, you can:

• Adjust parameters

• Drag and reorder signal blocks

• Configure Scenes

• Save, load, and export patches

• Import third-party IRs

• Configure USB routing and controller settings

Built-In USB Audio Interface

The MG-400 doubles as a USB audio interface, making it ideal for home recording, silent practice, and livestreaming. When connected to a computer, you can:

• Record guitar tracks directly

• Re-amp previously recorded signals

• Stream audio with Loopback mode

The unit also supports Dry Out and Re-amp recording, giving you greater flexibility during mixing and production.