MXR M400 Turbo Tuner

The MXR M400 Turbo Tuner is a new release with a real pedigree behind it. It is the result of a collaboration between MXR and Sonic Research, the company whose original Turbo Tuner earned a cult following as the secret weapon of session players and touring professionals, and is widely regarded as the most accurate pedal tuner ever made.

Sonic Research built that reputation on a true strobe tuner, a genuine stroboscope driven by your instrument's own signal rather than a digital emulation, accurate to within ±0.02 cents. For context, many popular tuners come in around ±0.5 cents, which is why so many studio engineers and intonation obsessives have quietly relied on the Turbo Tuner for years. For the M400, Sonic Research founder Roger Schlichtig engineered the pedal himself, bringing that same legendary engine into MXR's pedalboard friendly format.

The result delivers extremely accurate tuning with a fast, confident response and plenty of flexibility for different instruments, tunings and setups. A true strobe display keeps that ±0.02 cent precision front and centre, while six presets cover Chromatic, Guitar and Bass modes along with three fully custom slots. You can program your own open tunings and temperaments, handle drop tunings up to nine semitones, and set the A4 reference pitch anywhere from 300.0 to 599.9 Hz.

On your board it is just as versatile. You can choose between True Bypass and Buffered Bypass to suit your rig, connect over USB C for the editor software and firmware updates, and use the 9V DC output to pass power on to the rest of your chain. With all of this on board, the MXR M400 Turbo Tuner is far more than a classic pedal tuner.