Granith Grey Booster


Product Description

What kind of booster is necessary to maximize performance in any situation? We set out on a quest to find the answer…and we came up with the Granith Grey Booster!

  • Newly-designed clean booster pedal by BJF
  • Thoroughly dedicated to low noise, including minimized switching noise with our original filter circuit
  • Allows a boost of up to about +15dB of pure, high quality sound
  • Suitable for use with all types of pickups and amps
  • Maximizes the potential of any amp to awaken its true capability
  • High quality machined aluminum mini-housing
  • True bypass
  • Power or battery operated

BearFoot FX Introduces One Control BJF Series!

Now you can own a Björn Juhl-designed quality product that has great tone, but uses little real estate on your board!

BearFoot FX presents the BJF-designed
One Control Granith Grey Booster!



Mike Hermans

David Henriksson

MrExcane (Granith Grey Booster w/Anodized Brown Distortion)


The booster is an effect that amplifies incoming signals. If the incoming signal has noise in it, the noise is also amplified. This is an undeniable fact. However, you don’t have to compromise by thinking that this is unavoidable when you use a booster.

Try a truly noiseless booster. A world you’ve never experienced will unfold before you.

The One Control Granith Grey Booster is thoroughly dedicated to low noise. From the designing stage of the circuit, we tried to eliminate noise up to the limit of possibility. After repeated consultations between BJF and One Control, the booster now has a completely newly-designed circuit by BJF. It is full of BJF’s unique ideas that are liberated from conventional circuits. The case is made of high quality cut-out aluminum to protect the precious sound signals from inside and outside noises. It is also much more durable than die cast cases.

Furthermore, the switching noise that is inevitable with true bypass switching is minimized with our original filter circuit.

As a result, the Granith Grey Booster went beyond the capabilities of a compact pedal and attained an S/N ratio equivalent to a high-end vacuum tube audio amp.

Relevant and easy-to-handle boost gain

The One Control Granith Grey Booster allows a boost of about +16dB with the level knob set at the maximum level. You might think this is nothing extraordinary but we went through a number of tests with different values at our trial stage.

After repeated tests at different levels, it turned out that securing a +16dB boost was sufficient when a clean booster boosts up amps and distortion pedals or when enhancing the level of sound after distortion.

It might be impossible to create distortion with a booster alone. But in order to use a clean booster as a clean booster without losing dynamic range and outputting the guitar and bass sound while amplifying but basically keeping their original sound, and to realize the natural usability with any equipment with any connection, we determined the amplification at around +15dB which is appropriate for a clean booster.

And, if you turn the level knob down to the minimum, you can mute the sound and this allows the setting level cut and unity gain as well.

Pure texture

The One Control Granith Grey Booster will quickly make you aware of the pure tone that this pedal provides.

The frequency characteristic of the Granith Grey Booster is unique. A booster amplifies the incoming signals themselves. If you turn up the output without changing the frequency characteristic of incoming signals at all, you won’t be able to ignore the unnatural feeling it creates. It is the discomfort that was brought about by the difference between the frequency characteristic at the original output level and the actual output level.

The Granith Grey Booster is made in such a way that it outputs the incoming sounds just as they are while creating relevant frequency characteristics according to the output level when going through the boost circuit.

By doing so, the Granith Grey Booster realizes a pure and high quality boost sound without solidifying the sound or narrowing the dynamic range.

Suitable for any guitar, bass or equipment

The One Control Granith Grey Booster secured the 500kΩ input impedance to support any guitar and bass. You can use it by directly connecting to various guitars and basses regardless of types ranging from single coil, humbucking, active or passive.

Output impedance was kept low up to 2kΩ at most, which fits almost all pedal input and effects loop return on the amp.

Awakening amp potential

The One Control Granith Grey Booster is great with any guitar amp. It not only pushes a tube amp, but also is suitable for boosting drive channels inside transistor amps. It can also be used just like other amps for analog circuits even when used with a number of digital amps.

If you are using high-gain amps, connecting the Granith Grey Booster to the effects loop will allow the volume to be boosted with power amp distortion while taking advantage of strong preamp distortion at the same time.

The Granith Grey Booster will maximize the potential of any amp to awaken its true capability.

For any pedalboards

Even the greatest booster cannot be called user-friendly if it requires special care while transporting it.

One Control introduced an original super compact cut-out aluminum case for the Granith Grey Booster. The size allows compatibility with small pedalboards as well as larger ones.

We also made pedals this size to be battery-powered to allow usage without an outlet. The innovative technologies that arrange four PCBs inside secured the space to hold batteries while preserving the standard mini size.

The power consumption is kept below 1mA to allow longer battery power.

The One Control Granith Grey Booster works with center negative 9VDC adapters (EPA-2000 is recommended) or 006P 9V batteries.

  • When batteries need to be replaced the LED lights turn off and the sound starts to be distorted.

The drive voltage of the Granith Grey Booster is set at higher than the normal level (8.8-9.6V) to realize high quality sound. So the batteries need to be replaced before they get down to zero. Please use new batteries when you replace them.

The current consumption of the Granith Grey Booster is quite low, staying under 1mA, and allows longer battery life even at higher voltage.

Major usage of a clean booster

・As a gain booster for pedalboards

A clean booster amplifies incoming signals into the distortion pedal by connecting before other distortion pedals. This, as a result, creates effects like the ones created by moving gain knobs. You can adjust the output sound volume using the distortion pedal. And if you connect a spatial pedal after the clean booster, input to these effects is amplified and sometimes create its own unique effect.

・As a master volume on the pedalboard

If you connect a clean booster at the end of the pedalboard or after the distortion pedal, you can adjust the volume while maintaining the distortion created by other pedals. You can switch the booster on and off to switch levels of sound volume all at once, like switching between the rhythm and lead.

・As a gain adjuster for a tube amp

If you connect a clean booster before the tube amp input to adjust the volume boost setting, you can increase the strength of the distortion by turning on the booster.

On the other hand, if you distort the amp first and set the clean booster to lower the volume when it’s turned on, you can decrease the gain on the amp when it’s turned on.

・As a volume adjuster for tube amps

If you set a clean booster in the amp’s effects loop, you can adjust the output level of the signal sent to the power amp while preserving the preamp distortion. Set it to increase volume and you will be able to give power amp distortion along with the high volume when it’s turned on. Set it to lower the volume to use it like an attenuator.

“As a clean booster it is excellent and boost range is 15dB which is more than you’d need to set level for rhythm solo but 15dB is perfect for heating up a stale amplifier input and so it can work as a spare tube.

Indeed noise level is very low and among the very best I have ever heard in a booster. 🙂

One key to this is that the filtering of the circuit is made to fit the frequency range of an electric guitar and that lowers some overtones that could otherwise be present.”

— Björn Juhl


・Clean booster that was completely newly-designed by BJF
・Dedicated to low noise and attained the equivalent S/N ratio of a high-end audio amp
・Great ease of use with guitar, bass, amplifier and other effects
・High quality compact cut-out aluminum case
・Built-in battery possible

Input impedance: 500K
Output impedance: 2K
Maximum gain: 16dB
Drive voltage: 8.8V~9.6V
Current consumption: 1mA
S/N ratio: 115dB
Total harmonic distortion rate:
0.006% (1 kHz)
Size: 1.5W x 4D x 1.3H inches (excluding protruding parts)
1.85 W x 4D x 1.9H inches (including protruding parts)
Weight: Approx. 5 oz.
* Battery not included.