The Demeter Amplification MB-2B Fat Control Mid Boost/Buffer is a mid boost pedal with a built-in low impedance buffer1. It is aimed at players who want to bring out the natural midrange of the guitar rather than add gain: Premier Guitar described the objective as isolating the guitar's natural midrange frequencies and giving the player a way to shape them2. It sits in the wider family of boost pedals, and the built-in buffer also puts it in buffer pedal territory.
What it does
Demeter says the MB-2B boosts a wide mid-frequency range for a more distinct natural frequency boost than other approaches, and that it produces the sound equivalent of adding 5,000 feet of wire to your pickup1. That last phrase is the maker's way of describing what the low impedance buffer contributes to the signal1.
Controls
The pedal keeps things simple: one knob.
| Control | What it does |
|---|---|
| Flat/Fat | Affects the mid boost/buffer circuit, a wide variable gain mid-frequency power booster control1 |
Premier Guitar's reviewer found the pedal's boost character smooth and unforced: "Using a G&L ASAT Classic into the clean channel of a Crate V33H tube half stack yielded a very natural, smooth sustain," with notes blossoming and no unwanted distortion when digging in, even with single-coil pickups.2
What reviewers found
Premier Guitar's reviewer (JW) tested the MB-2B with a G&L ASAT Classic into the clean channel of a Crate V33H tube half stack and reported "a very natural, smooth sustain that was very impressive, with notes blossoming and no unwanted distortion when digging in"2. The same review lists the MSRP as $2192. A roundup of stompboxes in Premier Guitar's Stomp On This column also covered the Fat Control Mid Boost/Buffer3.
Demeter's product page carries a battery warning: "WARNING: If battery drops below 7 volts, noise will occur."1 Keep a fresh battery in it or run it from a reliable power supply to avoid noise as the battery fades.
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Questions
Does the Demeter MB-2B have a buffer?
Yes. Demeter Amplification describes the MB-2B as including a built-in low impedance buffer alongside the mid boost circuit. The maker says the pedal produces the sound equivalent of adding 5,000 feet of wire to your pickup, which points to the buffer's role in preserving the signal. Premier Guitar's review also identifies it as a mid boost and buffer pedal.
How much does the Demeter MB-2B cost?
Premier Guitar's review lists an MSRP of $219. That figure dates from the review published on September 1, 2026, and prices can change over time, so treat it as the manufacturer's suggested retail price rather than a current street price.
What does the Fat control do on the MB-2B?
The single Flat/Fat control affects the mid boost and buffer circuit. Demeter describes it as a wide variable gain mid-frequency power booster control. Premier Guitar's reviewer put it more plainly: the one knob takes you from a flat midrange frequency to a very pronounced mid hump, so you dial in how much midrange emphasis you want.
Is the Demeter MB-2B a clean boost or a mid boost?
It is a mid boost, not a flat clean boost. Demeter says the MB-2B boosts a wide mid-frequency range for a more distinct natural frequency boost. The single control runs from a flat midrange response to a pronounced mid hump, so at its lowest setting it sits close to flat, but shaping mids is the pedal's purpose.
Sources (3)
- MB-2B Midboost/Fat Control Pedal, Demeter Amplification
- Demeter MB-2B Pedal Review: Ultimate Fat Control Boost, Premier Guitar (www.premierguitar.com), 2008-10-15
- Stomp on This! 28 Stompboxes Reviewed, Premier Guitar, 2008-10-15