MXR M400 Turbo Tuner: Sonic Research Strobe Magic

Let’s be honest: nobody ever jumps for joy when spending their hard-earned cash on a utility pedal. But playing out of tune is a universal crime against music, and MXR has just delivered a ridiculously compelling reason to finally upgrade your rig. Welcome the MXR M400 Turbo Tuner, a compact pedalboard superhero born from an epic crossover event with the tuning wizards at Sonic Research.

If you are tired of the “close enough” guessing game of laggy LEDs and bouncing digital needles, this is the pedal you’ve been waiting for.

The Crossover Event of the Year

For their first-ever tuner pedal, MXR didn’t just reinvent the wheel; they partnered with the people who perfected it. At the heart of the M400 is the legendary core engine of the gold-standard Sonic Research Turbo Tuner. Personally engineered by Sonic Research founder Roger Schlichtig, the MXR M400 puts that lightning-fast, ultra-accurate strobe technology in MXR’s famously rugged, road-ready enclosure.

The result? Forensic tuning precision that ensures your open chords ring sweeter, your double-tracked studio parts sit tighter, and you feel infinitely more confident under the stage lights.

Strobe Accuracy You Can Actually See (and Hear)

Unlike standard tuners that digitally interpret your pitch, the MXR Turbo Tuner’s big, bright, modernized LED display is driven by the analog signal straight from your instrument. This means absolutely zero lag.

The real-time strobe readout tracks your pitch with fraction-of-a-cent accuracy. It’s incredibly intuitive: sharp notes rotate right, flat notes rotate left, and the spinning pattern slows to a satisfying creep as you lock in on perfect pitch.

Four selectable brightness levels ensure you can read the display clearly—whether you’re in a dimly lit dive bar or playing an outdoor festival stage at high noon.

A Swiss Army Knife for Alternate Tunings

Are you the kind of player who brings five guitars to a gig for different tunings? The MXR Turbo Tuner has you covered. Out of the box, it features a standard chromatic mode, but it also offers five highly customizable user presets.

Each preset supports up to 12 strings with offsets of up to ±50 cents. Whether you are experimenting with microtonal weirdness, running extended-range instruments, or using specific intonated setups with precise pitch offsets, you can save your configurations and access them with a simple tap of the footswitch mid-set.

Pedalboard-Friendly Power and Routing

Because pedalboard real estate and signal integrity are constant battles, MXR packed the M400 with modern connectivity upgrades.

It features switchable true bypass for purists who want a completely direct signal path, alongside a high-fidelity buffered bypass mode. The buffer includes three selectable submodes, keeping your tone pristine over long cable runs and through massive arrays of true-bypass overdrive pedals.

USB-C

Need more juice? A 9V passthrough output lets you power an additional pedal right from the tuner. It also includes an automatic power-up mode, a dedicated MUTE indicator LED, and a modern USB-C port on the side. That USB connection isn't just for show—it handles firmware updates and will connect to upcoming editor software, proving this pedal is built to adapt to the future.

The Bottom Line

With the M400 Turbo Tuner, MXR has officially eliminated every excuse you have for playing out of tune. It’s incredibly fast, surgically precise, and built like a tank.

The MXR Turbo Tuner hits the streets with a highly competitive price tag of $149.99 / £159.00. For more information, grab your perfectly intonated guitar and visit jimdunlop.com.

Fast Facts & Specs: MXR M400 Turbo Tuner

• Engine: Built on the gold-standard Sonic Research Turbo Tuner engine, engineered by Roger Schlichtig.
• Accuracy: Real-time strobe readout with fraction-of-a-cent precision.
• Display: Modernized LED window with 4 selectable brightness levels.
• Presets: 5 customizable user setups (supports up to 12 strings per preset).
• Offset Range: ±50 cents for advanced intonation and alternate tunings.
• Bypass Options: Switchable true bypass OR high-fidelity buffered bypass (with 3 buffered submodes).
• Connectivity: Standard 1/4" input/output, 9V passthrough output (powers an extra pedal), and USB-C for updates/editor software.
• Extras: Dedicated MUTE indicator LED and automatic power-up mode.

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