The MXR M108 10 Band EQ is a graphic equalizer pedal from MXR, the long-running effects brand now owned by Dunlop Manufacturing, Inc. A graphic EQ gives you a row of sliders, one per frequency band, so you can shape your tone visually: push a slider up to boost that frequency, pull it down to cut it. The M108 has ten of them, covering 31.25 Hz, 62.5 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 18 kHz, and each slider gives 12 dB of boost or cut. DIY Fever's reviewer calls that "slightly less than 18dB offered by the smaller model, but still plenty," referring to the MXR 6-Band EQ, which spreads fewer bands over a wider range each.1
The controls
The layout is simple: ten frequency sliders, plus two extra sliders at the ends. The Gain and Volume sliders control input and output volume, which matters because boosting frequencies adds level and can push the circuit into clipping.1
| Control | What it does |
|---|---|
| 10 frequency sliders | Boost or cut 31.25 Hz, 62.5 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 18 kHz by 12 dB1 |
| Gain | Controls input volume1 |
| Volume | Controls output volume1 |
One feature worth knowing about is the overdrive indicator: when the pedal gets overdriven, all the sliders blink. DIY Fever's reviewer found this very useful, since it is hard to tell by ear when the pedal is clipping when the signal itself is already heavily distorted.1
Power
The M108 runs on an 18V DC adapter only, with no battery operation. It will work with a 9V or 12V adapter, but with less headroom, meaning less clean level before the circuit clips.1
The included adapter is a traditional transformer-based unit with a fixed input voltage, so a US model adapter cannot be used with European mains power.1
The M108 and the M108S
The current version of this pedal in MXR's lineup is the M108S Ten Band Graphic EQ, documented in Jim Dunlop's manual with a frequency response of plus or minus 1 dB from 20 Hz to 20 kHz and a maximum output level of +14 dBV.2 Griffin Jennings, writing in Delicious Audio's EQ buying guide, sums up the M108S this way:
"Noise reduction circuitry, 18v operation, and 2 separate outputs make this a flexible and powerful EQ pedal."
So the M108S adds noise reduction and two separate outputs on top of the ten-band format, and runs at 18V like the M108. MXR also builds related ten-band pedals, including the MXR Ten Band EQ, the Kerry King Ten Band EQ and the KFK1 10-Band EQ, and smaller six-band models like the M109 6 band EQ and the Six Band EQ. For how EQ pedals fit into a board, see Equalization Pedals3.
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Questions
Can the MXR M108 run on a 9V battery?
No. The M108 is designed for 18V DC adapter operation only and has no battery option. According to DIY Fever's review, it will run on a 9V or 12V adapter, but with less headroom, so the full 18V supply is what the pedal is built around.
Can I use a 9V or 12V adapter with the M108?
You can, but the pedal is designed for 18V DC operation. DIY Fever's reviewer notes that it will work with 9V or 12V adapters, but with less headroom, meaning less clean signal before the circuit clips. For the pedal's full range, use an 18V supply.
What does it mean when the M108 sliders blink?
It is the pedal's overdrive indicator. When the pedal gets overdriven, all the sliders blink. DIY Fever's reviewer found this very useful, because it is hard to tell by ear when the pedal is overdriven if the signal itself is already heavily distorted.
Can the US adapter for the M108 be used in Europe?
No. The included adapter is a traditional transformer-based unit with a fixed input voltage, so a US model adapter cannot be used with European mains power. A player in Europe would need a suitable local adapter for the pedal.
What is the difference between the M108 and the M108S?
The M108S is the current Ten Band Graphic EQ in MXR's lineup, documented in Jim Dunlop's manual with a frequency response of plus or minus 1 dB from 20 Hz to 20 kHz, a maximum output level of +14 dBV, noise reduction circuitry, 18V operation and two separate outputs. The M108 is the earlier version of the same ten-slider format.
Does the M108S have two outputs?
Yes. According to Griffin Jennings in Delicious Audio's EQ buying guide, the M108S Ten Band EQ has 2 separate outputs, alongside noise reduction circuitry and 18V operation, which he describes as making it a flexible and powerful EQ pedal.
Sources (3)
- Reviews > Effects > MXR 6 vs 10 Band EQ : DIY Fever, DIY Fever (diy-fever.com)
- M108S.pdf, Jim Dunlop, 2025
- 2023 UPDATE! Best EQ Pedals For Guitar: Graphic & Parametric, Delicious Audio, 2023-12-13
