The Little Green Emphaser is a dynamic boost pedal from One Control, designed by Bjorn Juhl, that lets a player put emphasis on a specific frequency range. One Control describes it as primarily meant to be used as a pre-driver, though it also distorts slightly, so it can add a touch of grit of its own while pushing the drive stage that follows it1. It belongs to the same green family of circuits as the Little Green Wonder overdrive, and it sits in the wider world of boost pedals as a tone-shaping booster rather than a clean volume push.
How the Blend knob works
The pedal's circuit is a combination of a booster and a treble booster, both placed on a panorama pot and optimized for the lowest possible noise1. The Blend knob balances or blends the straight booster and the treble booster, which allows the player to put emphasis on a specific register of the guitar's sound1. Turn it one way and you get more of a full-range straight boost; turn it the other and the treble booster takes over, brightening the top end.
"The LITTLE GREEN EMPHASER is a dynamic boost pedal which allows the player to put emphasis on a specific frequency range."
The Blend knob with single coils and humbuckers
How the Blend knob behaves depends on the pickups you feed it, and One Control gives specific guidance for both common types1:
- Single coil pickups: you will notice more of a treble boost rather than a straight boost. In turn, this keeps hum levels low and adds body to the sound1.
- Humbucker pickups: the Blend knob was tuned to allow crispness and body, with a small amount of distortion on transients1.
That pickup sensitivity is the pedal's main character: rather than a fixed EQ, the same knob setting responds differently to a Strat and a Les Paul, which is where the "dynamic" in its description comes from1.
Placement and a Fender trick
One Control says the Little Green Emphaser typically works best at the beginning of your signal chain, where a pre-driver belongs, ahead of your overdrive or distortion pedals1. There is also a use that has nothing to do with boosting: with Fender amps, the pedal can be used to correct the phase of the Reverb and Normal channel, a long-standing quirk of those two-channel circuits1.
Power, noise and specifications
Power is straightforward: a 9V battery or a standard DC power supply, at a drive voltage of 9V1. Current consumption is 2mA, low enough that any supply handles it easily1. The maker specifies an input impedance of 500K, an output impedance of 25K, and a signal-to-noise ratio of -80dB1. The enclosure is aluminum, measuring 39W x 100D x 31H mm excluding protruding parts and weighing approximately 160 grams1.
The maker's page gives the size as 39W x 100D x 31H mm, excluding protruding parts. Either way it is a compact, low-profile pedal.
Relation to the Little Green Wonder
The Emphaser shares its green livery and its designer with the Little Green Wonder, an overdrive that has been sold under both the BJFe and Mad Professor names. Guitar World's review of the Mad Professor version lists it as true bypass, running on 9V center negative at 4mA, twice the Emphaser's 2mA draw2. According to Aion FX, the earliest BJFe-built Little Green Wonder versions used a linear taper Tone control, changed to log before very many units were produced, a detail that matters to players comparing vintage units of that pedal3. The Emphaser is the boost-oriented sibling in that family, built for shaping what a following drive pedal receives rather than producing full overdrive itself.
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Questions
Does the One Control Little Green Emphaser run on a battery?
Yes. One Control lists the power options as a 9V battery or a standard DC power supply, with a drive voltage of 9V. Current consumption is very low at 2mA, so a battery lasts a long time and the pedal is easy on any daisy-chained supply.
Is the Little Green Emphaser true bypass?
Yes. One Control specifies True-Bypass Switching, so when the pedal is off your guitar signal passes through without loading the circuit.
Where should the Little Green Emphaser go in a signal chain?
One Control says the pedal typically works best at the beginning of your signal chain. That makes sense given its role: it is primarily meant as a pre-driver, pushing whatever distortion or overdrive stage comes after it.
Who designed the Little Green Emphaser?
The pedal is credited to Bjorn Juhl, the designer behind One Control's BJFe line of pedals. It sits alongside his Little Green Wonder overdrive in the family of green One Control boost and drive circuits.
How much current does the Little Green Emphaser draw?
One Control lists current consumption at 2mA, which is very low even by boost pedal standards. For comparison, the related Mad Professor Little Green Wonder draws 4mA according to Guitar World's review.
Sources (3)
- LITTLE GREEN EMPHASER (OC-LGEn), One Control USA
- Mad Professor Little Green Wonder review, Guitar World, 2026-06-23
- Viridian Dynamic Overdrive, Aion FX, 2020-08-28
