MXR MB301 Bass Synth

A Modern Bass Synth Inspired by the Golden Age of Synth Lines

The MB301 Bass Synth follows the grand tradition of "analog synth-style" basses that have defined funk and pop, while meeting the current expectations of bassists: clear attack, musical sustain, and controls right at your fingertips. Developed with Ian Martin Allison, it aims for sounds inspired by classics like Stevie Wonder, Parliament Funkadelic, or Michael Jackson, without turning your playing into an obstacle course.

For Which Bassists and Styles?

This bass synth pedal is aimed at intermediate to advanced bassists who want an expressive synth sound without dealing with a complicated setup. It excels in funk, pop, hip-hop, electro, alternative rock, and modern metal, both in studio and live. In a band setting, the wet/dry mode is formidable for maintaining the bass foundation while adding a synth layer on top.

Settings, Presets, and Advanced Functions: Simple on the Surface, Deep in Practice

The knobs shape the essentials: Sub Mix controls the sub-octave level, Envelope adjusts the filter response (from percussive bounce to slow sweeps), Cutoff and Resonance sculpt the character, Mod adds movement, and Mix balances dry/wet. The Voice button thickens the patch with additional oscillators, while Shape selects the waveform (triangle, sawtooth, square).
Want to go further? Secondary parameters provide access to compression, output gain, glide, noise mix, tracking (4-string / 5-string / guitar), gate, and output routing. And in live use, the footswitch also allows preset scrolling (hold) or activating a "freeze" function to hold a synth note depending on the configuration.

Sound Character

The MB301 delivers a fat and articulated synth texture: solid fundamentals, an envelope that "speaks" like a monosynth filter, and modulation ranging from subtle shimmer to more pronounced pulses. Its character can remain relatively clean and funky or become more aggressive depending on the waveform and resonance settings. In real-world use, it's notably found with Ian Martin Allison (development/demo), III (Sleep Token), Marc Stranger-Najjar, and Ida Becker, proving it integrates well into both modern rigs and vintage contexts.

Technical specifications

Effects	Octaver / Harmony, Bass, Envelope / Auto-wah, Synthesizer	Type	sector
Technology	Digital	Use	Bass
Format	Pedal	Color	Black
Inputs	1 x jack	Power supply included	No
Outputs	2 x jack	Preset number	8
EQ	Filter	Power supply	DC 9 V
User memories number	8

Processing	digital	CTR Jack	6.35mm Jack (expression / external switch in TAP/EXP mode, or right channel audio output in AUDIO mode)
Filter	4-pole resonant low-pass	Possible outputs (depending on setting)	mono, wet/dry, stereo
Presets	8 presets + "live" mode	Mono	true bypass
Knobs	Mix, Sub Mix, Cutoff, Resonance, Envelope, Mod	Wet/dry and stereo	buffered bypass
Buttons	Voice (additional oscillators), Shape (waveform selection), Preset (selection)	Input impedance	1M ohms
Waveforms	triangle, sawtooth, square	Output impedance	100 ohms
Functions	preset scrolling via footswitch (hold), freeze function (depending on configuration)	Maximum input level	+5 dBV
Advanced parameters (via secondary functions)	compression, output gain, glide, gate sensitivity, tracking (4-string / 5-string / guitar), dry thru FX, output mode, mod blend, noise mix, etc.	Noise floor	-97 dBV
Input	6.35mm Jack (mono)	Dimensions	57 x 108 x 50 mm
Output OUT	6.35mm TRS Jack (mono or stereo depending on configuration)	Weight	255 g