Boss MD-500 Modulation

The Boss MD-500 Modulation is a digital modulation pedal from Boss that packs 12 modes and 28 modulation effect algorithms into a compact 6.75" x 5" enclosure¹². Boss says every algorithm was newly developed for the pedal, covering the go-to standards: chorus, vibrato, flanger, phaser, tremolo, rotary, classic vibe, and ring mod¹. Guitar World's buying guide also notes slicer, Roland dimension chorus, detune and bit-crusher sounds among its modes³.

It is a deep-editing machine rather than a simple stompbox: Bass Musician Magazine's Ty Campbell described it as having "twelve modes and 28 modulation types, all with deep editing parameters"⁴.

What it does: 28 algorithms in 12 modes

The leftmost knob selects from 12 tone categories, and each category holds multiple algorithm flavors². The chorus setting alone offers four: a clone of the classic CE-1 (the first-ever Boss effect), the CE-1's vibrato effect, a Dytronics Tri-Stereo Chorus clone, and a brand-new chorus algorithm². The original CE-1 Chorus Ensemble was a mains-powered unit with both chorus and vibrato modes, and MusicRadar credits it with democratising modulation by offering mono and full stereo operation⁹¹⁰.

Editing goes well beyond the panel knobs. Premier Guitar's reviewer found the flanger alone has 18 parameters, including extensive EQ controls, a menu of 10 modulating waveforms, and high- and low-frequency damping². A large LCD shows the patch name and other performance information and makes it easy to view and adjust deep parameters¹.

Real-time control is assignable to almost any parameter, up to eight parameters at once².

Power and connections

The MD-500 runs on a 9V power supply⁶², and Premier Guitar's reviewer found it also carries a battery compartment: "you'll burn through the included quartet of AAs in about four hours"². It has stereo outputs, and That Pedal Show's presenters noted "it has stereo obviously" when demoing it⁸.

Running two effects at once

The MD-500 hosts two simultaneous effects². You can toggle them on and off via the A and B footswitches, engage both at once, or run them in series or parallel². Each of the 297 memory banks stores a pair of sounds and its settings².

History: the 500 series and the Strymon Mobius

Boss unveiled the MD-500 alongside the RV-500 Reverb in June 2017, with both available from August 2017 at £375 each in the UK¹¹¹². Gearnews reported the same launch with an RRP of GBP 375 due out in August⁵. On That Pedal Show, the presenters recalled it launching at "329 English Pounds in july 2017"⁸.

The pedals share the basic design of the companion DD-500 Digital Delay, Boss's 12-mode digital delay, with 32-bit/96 kHz AD/DA, deep programmability, and advanced features¹³⁵¹. Gearnews noted the MD-500 uses the same 32-bit/96 kHz converter with internal 32-bit float calculation as the DD-500⁵¹⁴.

The MD-500 is also widely compared to the Strymon Mobius, a multi-modulation pedal with twelve modulation machines. Writing at Guitar Pedal X in September 2017, Stefan Karlsson said the Boss is "obviously to a significant degree 'based' on the Strymon Mobius," calling it a tribute in basic form factor and footswitch layout, and noted that where he used mostly the Flanger, Phaser and Tremolo modes on the Mobius, he found himself using pretty much all the modes on the Boss¹⁵.

Firmware and drivers

Boss provides system updates and computer drivers for the MD-500. The update files ship as md500_sys_v105.zip containing MD500ROM.BIN and ROMINFO.TXT, and the update requires a USB cable compatible with USB 2.0 Hi-Speed and a computer with a USB 2.0 connector, Windows or Mac⁷. Drivers are available for Windows (Ver.1.0.0) and macOS, and to use them the MD-500's USB MODE must be set to "VENDOR"¹⁶. An MD-500 Editor application requires system Ver.1.00 or later¹⁷. The owner's manual is available from Boss's support pages¹⁸.

To update the firmware:

1. Set the DEPTH, E.LEVEL, PARAM 1 and PARAM 2 knobs to the minimum position⁷.
2. Connect the MD-500 to your computer with a USB 2.0 Hi-Speed cable; it appears as a drive called BOSS_MD500⁷.
3. Run the update on AC power, not batteries⁷.
4. To check the current system version, hold down the EXIT button and connect a plug to the INPUT A/MONO jack to power on⁷.

What reviewers said

Premier Guitar's reviewer found the effects "inevitably clean, quiet, and transparent. They sound great in stereo, but they're satisfying in mono, too," and true to the original pedals they model, crediting the 32-bit, 96 kHz convertors². MusicRadar's Trevor Curwen's overall verdict: "A powerful machine with a flexibility that's hard to beat."¹⁹

On price, Guitar World listed the MD-500 at $1,199²⁰, while MusicRadar noted in 2026 that it "may be more cost-effective at a £306 street price"²¹; the figures come from different markets and dates.

That Pedal Show demoed the MD-500 on release, walking through its modes, stereo operation and launch pricing⁸.

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