MXR Booster Mini

The MXR Booster Mini is a compact boost pedal from MXR that packs two well-known circuits into one small box: the clean boosting power of the MXR Micro Amp and the preamp section of the Echoplex tape echo, a stage sound players have chased for decades. MXR's own pitch for it is to "save space, season up your tone, and fly high above the mix"¹. It sits in a lightweight, space-saving mini housing aimed at players who want a boost and a touch of character without giving up much pedalboard real estate¹.

The controls: Volume, Tone and the internal trim

The Booster Mini keeps its front panel simple, with the deeper tweaking tucked inside³⁴.

The Volume control is the main event: +25dB is a large amount of gain for a mini pedal, enough to push an amp's front end into breakup on its own or to lift a solo line clear of the band. The Tone control gives you a way to tame the brightness that a big boost can add, and Premier Guitar called the combination "a flexible tone control" that makes the pedal "a most malleable and miniature means of tailoring your drive"³¹.

The Echoplex Preamp's gain trim pot is on the inside of the pedal rather than on the surface³. Turning it up adds a little extra grit to the signal, which is the part of the pedal that comes from the tape echo's preamp rather than from the Micro Amp side⁴. Premier Guitar's reviewer flagged this as a practical drawback: "Internal trim pot for Echoplex Preamp is a hassle"³. If you like to tweak grit levels between songs, reaching for a screwdriver mid-gig is not ideal, so most players will likely set it once and leave it.

Circuit roots: Micro Amp and Echoplex Preamp

MXR describes the Booster Mini as delivering "the sonic secret sauce of the Echoplex Preamp with the legendary boosting power of the MXR Micro Amp" in its mini housing¹. Those are two distinct pieces of guitar history in one circuit.

The Micro Amp side of the Booster Mini's lineage is the boost MXR itself describes as sought-after, the kind of clean level raise that pushes the front of an amp harder⁵¹. The current Micro Amp+ version, which shares this lineage, is built to "boost and sweeten up your guitar or bass tone and drive the front of your amp," and it works for guitar or bass alike⁶.

The Echoplex side comes from the preamp stage of the Echoplex tape echo unit. Players running their guitars through the whole machine found they liked what that preamp did even without the echo, and that sound has been borrowed by pedal makers ever since. In the Booster Mini, Guitar World's Paul Riario wrote that the pedal combines "the sought-after boost found in the MXR Micro Amp and the subtle gritty edge from the Echoplex Preamp, which also offers a touch of musical compression"⁵.

That compression is worth noting for players comparing boosts: a purely clean booster only makes things louder, while the Echoplex side of this circuit colors the signal. Premier Guitar's review listed "nice compression from Echoplex side" among its positives³.

How it differs from a Micro Amp

If you already know the Micro Amp family, the Booster Mini is not a reissue in a smaller box. The differences come down to circuit and controls¹⁵⁷:

• The Micro Amp is a straight booster with no tone shaping⁸; the Booster Mini adds a Tone control that rolls off highs⁴.
• The Booster Mini adds the Echoplex Preamp circuit, with its gritty edge and touch of compression, on top of the Micro Amp-style boost⁵.
• The Echoplex gain is set by an internal trim pot³, where the Micro Amp+ puts its shaping on the outside: its GAIN knob controls the overall amount of signal boost and its BASS knob cuts or boosts low frequencies³⁷.

So a player who wants a transparent level lift with external control over the low end is better served by the Micro Amp+, while a player who wants boost plus a bit of baked-in character in a smaller footprint is who the Booster Mini addresses⁷⁵¹.

What reviewers made of it

Published reviews have been positive on the sound and split on the layout. Premier Guitar's quick-hit review summed up its strengths as "many varied and potent drive tones" and "nice compression from Echoplex side," against the hassle of the internal trim pot³. Guitar World's Paul Riario framed the pedal's appeal as its combination of the two circuits, with the Echoplex side supplying grit and musical compression over the Micro Amp's boost⁵.

At a street price of $99³ against a list price of $125.99², it sits in the middle of MXR's mini-pedal pricing, and its mini housing makes it a candidate for the tight corner of a board where a full-size boost would not fit¹.

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