MXR 10-Band EQ

The MXR 10-Band EQ is an equalizer pedal released in at least four versions by MXR/Dunlop. There are also smaller 6-Band versions, called the M109 and M109S, released in the 2010s.

MXR 10-Band EQ Versions

The first version, called the MX-108, was released in the 1970s, had a blue paintjob with white lettering, a 120V power cord, and 10 sliders for each filter band.

A second version called the M-108 was released in the 2010s. It had a black finish with white lettering and scrapped the power cord in favor of an 18VDC power jack.

A special version of the M-108 was released in homage to Kerry King of Slayer, called the MXR KFK1, included an additional output for driving two separate amps and a tattoo-inspired design.

The most current version, as of 2023, is the M108S which is the same as the Kerry King version except rehoused in a polished aluminum enclosure with bright blue LEDs on each slider.

MXR MX-108 Modifications

The original circuit takes in 120VAC from the wall and converts it to 15VDC, allowing for substantial headroom. MXR later adapted to the demands of the market in the M-108 version. They ditched the power cable for a standard power adapter plug – this time requiring 18VDC.

The modifications below are specifically for the vintage MXR MX-108:

• Synergy Mod (MX-108, Removes the power cord and installs an 18VDC power jack)
• LED + True Bypass Mod (MX-108, Adds a True Bypass switch and indicator LED to the MX-108)

MXR M-108 Modifications

The following mods are strictly for the M-108 black with white lettering version of the 10-Band EQ:

• Kingsley Mod (M-108, Adds a second output jack just like the Kerry King KFK1 version)

MXR M108S Modifications

The most recent M108S is the pinnacle of the 10-Band EQ series, as it encompasses all the upgrades of the previous versions into one. The only gripe that users of the M108S have is with the bright blue LEDs on the sliders (as per this forum post). I can perform the LED Dimmer mod that replaces the resistors for a less blinding experience. See this video for before/after and the details for the mod.

The following mods are strictly for the M108S version of the MXR 10-Band EQ series:

• LED Dimmer (M108S, adjusts the brightness of all the blue slider LEDs)

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Common Accessories with MXR 10-Band EQ Modifications

Isolated Power Supplies

There are plenty of power supply units that carry 18VDC as an option. My recommendation is the Voodoo Labs ISO 5 for small pedalboards, and an MXR ISO Brick for medium-sized pedalboards.

Power Cables

Got questions? I got answers!

Hopefully I covered everything above, but if you have any questions on the MXR 10-Band EQ mods above feel free to contact me using this contact form!

If the mods above aren’t what you’re looking for, you can always request a custom modification through the Custom Guitar Pedal Modification Request form.

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