BOSS MD-500 Modulation Effects Pedal

The BOSS MD-500 is a digital modulation multi-effects pedal for guitarists who want a broad selection of chorus, phaser, flanger, tremolo, rotary, filter, and other modulation sounds in one floor unit. It combines 12 effect modes and 28 modulation types with deep parameter editing for creating and recalling tailored sounds. Its stereo-capable A/B inputs and outputs support mono rigs as well as more involved pedalboard and amplifier setups.

This pedal suits players building a flexible live rig, recording setup, or compact board that needs more than one dedicated modulation effect. It provides 297 onboard patch memories, allowing sounds to be organized across 99 banks with A, B, and C patch locations. Dedicated controls, a graphic LCD, and footswitch operation keep core adjustments accessible without relying solely on computer editing.

The MD-500 covers familiar modulation categories including chorus, flanger, phaser, classic vibe, vibrato, tremolo, dimension, ring mod, rotary, filter, slicer, and overtone. Its processing platform uses 32-bit AD/DA conversion, 32-bit floating-point processing, and a 96 kHz sampling frequency. These specifications support detailed modulation processing while maintaining a wide range of editable effect behavior.

A/B Simul mode lets two patches operate at the same time for layered modulation sounds. The two effects can be connected in series or parallel, and their signals can be mixed or routed separately through the A and B outputs. Selectable buffered bypass or relay-based true bypass allows the pedal to be matched to different pedalboard signal-routing preferences.

The built-in Insert Loop function is designed for integrating external effects, particularly gain and drive pedals, into a patch's signal order. This makes it possible to place modulation before or after the connected external effect, with additional routing possibilities in A/B Simul mode. MIDI I/O and USB-MIDI add options for synchronizing tempo, changing patches, editing, and backing up settings within a larger performance or recording system.

Key Features

• 28 Modulation Types: Covers classic and original BOSS modulation algorithms across 12 modes.
• 32-Bit/96 kHz Processing: Uses 32-bit conversion, floating-point processing, and 96 kHz sampling.
• A/B Simul Mode: Runs two patches together in series or parallel configurations.
• Insert Loop: Places external pedals before, after, or between modulation effects.
• 297 Patch Memories: Stores organized custom sounds in 99 banks of three patches.
• MIDI and USB-MIDI: Supports external control, synchronization, editing, and patch backup.

Design & Installation

The MD-500 uses a compact blue floor-pedal format with a 128 x 64-dot backlit graphic LCD, six control knobs, navigation buttons, and three footswitches. Its rear panel provides dual A/B audio inputs and outputs, MIDI IN and OUT connectors, USB Type-B, DC input, and a CTL 1,2/EXP jack. The manufacturer does not list an enclosure material in the published specifications.

For a mono rig, connect the instrument to INPUT A/MONO and the amplifier or next device to OUTPUT A/MONO. Use both A and B connections when integrating stereo sources or stereo outputs, and use the CTL 1,2/EXP jack with compatible optional footswitches or expression pedals for additional control. The pedal can run on four AA alkaline batteries or an optional BOSS PSA-series AC adapter; use a commercially available USB 2.0 cable for computer connection.