MXR M133 Micro Amp Review (July 2024)


Last updated on July 21, 2024 3:02 am Details


In this review post we’re going to be discussing the MXR Micro Amp gain boost pedal, including an overview of its unique features.

Product Description

The Micro Amp is a terrific method to increase your signal for lead work or switch between two different guitars (i.e. humbuckers to single-coils) with unrivalled power by adding a predetermined amount of gain with only a single control. It can also act as a constant boost in a long effects chain when signal dropoff is an issue.

Guitarists are always on the lookout for new and improved pedals to help them attain their ideal sound. But what if the amp sounds great but just needs a little extra Gain? Overdrives and treble boosters would distort the frequency response, which is undesirable in this scenario.

For many years, the MXR Micro has been the correct thing – without distorting the sound, the amp adds the kick that was still missing; ideal for bringing out the leading sound from ancient Marshalls, Fenders, and Vöxen without destroying their beloved characteristic sound.

One 9-volt battery (remove the bottom plate to install), a 9-volt AC adapter (such as the Dunlop ECB003/ECB003E), or a power supply (such as the DC BrickTM) are all options for powering the MXR Micro Amp.

Product Features

  • Adjustable boost
  • Perfect for switching between guitars with unmatched output
  • Great for use with long signal chains, or anytime signal drop-off is a problem
  • Knob for gain, status LED
  • Hardwire bypass
  • Sturdy metal housing
  • Operation via optional 9V battery or optional 9V power supply unit
  • Made in USA

Pros & Cons


  • Extremely affordable
  • Compact, strong metal chassis
  • Easy to use
  • True bypass
  • Rugged footswitch
  • Doesn’t affect tone when engaged


  • Not much

MXR M133 Micro Amp Demonstration

Our Verdict

The Micro Amp+ is a powerful studio and backline booster pedal. If you’re on the road and working with different amps each night, the Micro Amp+ makes it simple to switch between them, reducing the high-mid spike from a Marshall one night and coaxing a Vox-like bite from a Fender the next.

It may boost the high-mid zing of humbuckers or soften the sting of a single-coil Stratocaster, all while giving you more freedom in a band mix. Although the Micro Amp+ doesn’t produce as much distortion as typical overdrives, its wide range can make you a hero in a studio or onstage when everything else is muddy.

Overall, considering the build quality, sound quality and affordability, this is a winner in terms of the characteristics we’d consider for a guitar booster pedal.

Where to Buy

The best place to buy this product has to be Amazon, due to their competitive pricing and fantastic customer service.

MXR M133 Micro Amp

as of July 12, 2024 5:44 pm

Pricing History

Price History for MXR M133 Micro Amp


Current Price $99.99 July 12, 2024
Highest Price $99.99 September 19, 2023
Lowest Price $90.17 December 18, 2023
Since September 19, 2023

Last price changes

$99.99 December 27, 2023
$90.17 December 18, 2023
$99.99 September 19, 2023

as of July 12, 2024 5:44 pm
Last updated on July 12, 2024 5:44 pm

Buyers Guides This Product Is Featured In

Additional information

Item Weight

1 pounds

Product Dimensions

5.9 x 4.6 x 2.7 inches

Domestic Shipping

Currently, item can be shipped only within the U.S. and to APO/FPO addresses. For APO/FPO shipments, please check with the manufacturer regarding warranty and support issues.

International Shipping

This item can be shipped to select countries outside of the U.S. Learn More

Country of Origin


Item model number



1 9V batteries required.

Is Discontinued By Manufacturer


Date First Available

January 16, 2004

Color Name



9 Volts


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