The MD-500 is a greatest hits collection of Boss modulation effects, collated in a compact 6.75" x 5" enclosure. It’s a stereo digital device that sounds convincingly analog, thanks in part to 32-bit, 96 kHz convertors—impressive in this price range. It reprises sounds from Boss’s early years, adds cool new ones, and provides sufficient control and connectivity to suit the most ambitious MIDI-controlled pedalboards.

Twelve Ways to Wobble
The MD-500’s editing options can get deep, but they don’t necessarily have to. You can access the basic sounds via a set of intuitive stompbox-style knobs. The leftmost knob selects from 12 tone categories:




• classic vibe (Uni-Vibe sound-alike)

• vibrato


• dimension (plush stereo chorus from the 1980s Dimension D)

• ring modulation

• rotary (Leslie cabinet emulation)

• filter

• slicer (gating/chopping effect)

• overtone (synthesizes resonant pitches for electric-organ-style sounds).

The tones are excellent, but you probably knew that already. Many of these have been stompbox staples for decades, and all are true to the originals. Additionally, the effect categories have multiple modes.

Tones are inevitably clean, quiet, and transparent. They sound great in stereo, but they’re satisfying in mono, too.

The chorus setting, for example, offers four flavors: a clone of the classic CE-1 (the first-ever Boss effect), CE-1’s vibrato effect, a clone of the Dytronics Tri-Stereo Chorus (an ’80s session-cat sound), and a brand-new chorus algorithm. There are far more colors here than the 12-position knob might suggest.

There isn’t room to describe all the tones, but they’re inevitably clean, quiet, and transparent. They sound great in stereo, but they’re satisfying in mono, too.

Storage Space
The MD-500 hosts two simultaneous effects. You can toggle them on/off via the A and B footswitches, engage both effects at once, or run them in series or parallel. A small LED screen displays your current data. You edit via cursors and knobs. One hardware knob is a dedicated tempo control. There’s also a dedicated tap-tempo foot switch.

A pair of sounds and its attendant settings constitutes a bank. Pressing the center and right foot switches advances to the next bank, while pressing the center and left ones retreats. The ergonomics are great—pressing two switches simultaneously is easy for all conventionally sized feet. You can store a whopping 297 banks in memory.



Vast collection of classic Boss modulation sounds. Deep editing if desired. Small pedalboard footprint. Real-time control. Great price.



Ease of Use:




Boss Modulation MD-500

The Lower Depths
You may be able to uncover all this without consulting the 30-page manual. But if you are the manual-cracking type, the MD-500 will reward your diligence. Edit options are extensive. Take the flanger, for example: Its 18 parameters include extensive EQ controls, a menu of 10 modulating waveforms, high- and low-frequency damping, and more. But that journey is strictly optional. You can also approach the effect as a simple pedal flanger, setting the rate, depth, feedback, and mix via the intuitive hardware knobs.

While you’re under the hood, you can exploit the MD-500’s impressive routing and real-time control skills. The rear panel’s stereo 1/4" jack lets you connect one or two external footswitches or a single expression pedal (neither is included). You can assign these to almost any parameter and control up to eight parameters at once. Tone-tweakers will hyperventilate.

There’s even a simple effects loop. You can insert mono pedals between the input A and output B jacks, saving the loop’s on/off status and specifying whether the external effect comes before or after the MD-500’s effects. You can also reassign the tap-tempo switch to other functions on a per-patch basis. Old-school MIDI jacks enable the MD-500 to play nice with pedalboard switchers. You can also sync effects to a computer via USB.

The MD-500 has a battery compartment, but you’ll burn through the included quartet of AAs in about four hours. Boss recommends their PSA adapter (not included), but you can use other 9V power supplies as long as they provide at least 500 mA of amperage.

The Verdict
The MD-500 is a comprehensive collection of Boss modulation effects in a compact, pedalboard-friendly package. Operation can be as simple or tricky as you like. You can spin a few stompbox-style knobs for the basics, or spelunk the sub-menus for creative customization. Real-time control and connectivity options are legion. The bang/buck ratio is off the charts. With its retro-approved tones and modern functionality, the MD-500 looks backwards and forwards simultaneously. It’s a fine view in both directions.

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