Prussian Blue Reverb

OneControl developed a time-based pedal for the first time.
A battery operated reverb effector.
When OneControl was releasing various distortion pedals,
we started developing these battery operated reverb pedals.
Is it actually possible?
That was the question in our minds.
Our limit-defying nature gave us not choice but to overcome this.
It was a challenge given to us.
And now we have it. This is the reverb all guitarists desire.

A reverb effect simulates a mild reverberation that is created when a sound is reflected in space.
Whether an electric guitar/bass or other electric or acoustic instruments, all sounds accompany reverberation in space before reaching human ears.
The sound that is created for an ideal reverberation heard in the best spot in space is what an instrument at its best can offer.

The Prussian Blue Reverb is a reverb effector that creates the ideal reverberation. History has seen various reverb systems that make it happen. Some people made a room particularly designed for reverberation. Plates, springs, digital reverb and all other historical evolution of reverb effects were results of pursuing ideal reverberation.

Digital effect technologies have now developed and these past reverb effects can now be easily simulated. If you want the sound you heard in past classics, these simulated effects are useful. Also, new unique effects that are based on reverb but complemented with new ideas also create amazing effects.

The Prussian Blue Reverb is different from the effectors that took off from historical simulation and reverberation.
BJF wanted to create reverb effects that are really sought by players when they play guitars and bass.

He did not want rich and powerful spring reverb or a reverb tone produced as a deluding effect with a higher octave. He pursued ideal reverb tones in order to maximize the potential of the instrument by keeping the effector on all the time.

The Prussian Blue Reverb is a reverb pedal that recorded BJF’s custom programs on a 24bit high acoustic quality digital chip. Its dry signal is naturally analog-dry-through that is not converted to digital.

Ideal reverb tones for guitarists and bassists are neither spring, hall, nor room. It is a mixture of their strengths but goes the middle way and exhibits strong presence.
To put in more relative terms, it’s closer to the hall tone than to spring but not as bright as hall reverb.

By randomly modulating the decay time of reverb signals, it creates the effects by which sounds spread in the space while remaining mono effects. This random modulation is programed to imitate the string vibration property of guitars and basses.
This is a property unique to the Prussian Blue Reverb, different from the conventional reverb algorithm that creates layers of individually recorded reverberation. It is natural and solid but not too plain, and is most similar to the ideal reverb tone that players really seek.

Prussian Blue Reverb has a dynamics range that is five times as broad as general spring reverb. It is filtered to prevent it from being too tremble or too saturated with the bass. Its dynamics range that is broad for a reverb effects creates open spatial property.

At the same time, decay control was added to prevent reverberation from interfering with rhythm. The decay control designed by BJF does not simply adjust the overall reverb length. It is a control for enabling easy setting for seamless reduction according to the guitar tones. The decay time can be set from 2ms to 2s from soft reverberation placed on top of the sound to long-lasting reverberation.
The precise decay control and overwhelmingly natural reverb tones are similar to studio-level reverb as a result of modern technologies that are designed specifically for guitars and basses.

The Prussian Blue Reverb’s early reflection is set to be short. Thanks to the short duration between the guitar/bass attack to the reverb startup and the overwhelmingly natural reverb tone, unnatural reverb does not stand out and you can created a sound that spreads sterically as soon as you play. This is a sensation only the Prussian Blue Reverb can provide.

The Prussian Blue Reverb allows you to mute a dry signal with the Kill Dry switch. While it is a common function among rackmounts, it is also effective when it’s connected to a parallel effects loop on some guitar amps and mixers.
If you connect the Prussian Blue Reverb with the Kill Dry on to the main signal chain, you can use it to create slow volume effects by setting the early reflection to short.

* It takes several seconds from the time the power is turned on until the digital chip inside is stabilized and starts running. The tone may become unstable during this period, so please maintain the bypass for several seconds after connecting an adapter.

In developing reverb effects, I sought the reverb setting guitarists wanted. They often want a reverb tone that is between spring and hall but slightly closer to the hall side as is the case for me. I added more precise decay control that will not interfere with the rhythm.
I was confident but when I actually heard the tone Prussian Blue Reverb (PBR) made, it was amazing. You can say that there is unlimited space expanding in this small pedal.
This pedal is designed for guitars and basses. It is not only suitable for electric guitars and basses but also for acoustic guitars and basses as well.
PBR provides the best sound when it’s connected after distortion effects and before tremolo effects.

───Bjorn Juhl


– Newly designed reverb pedal by BJF
– Sound that is overwhelmingly natural and extends sterically
– Decay control that does not interfere with rhythm and allows natural setting
– Kill Dry function
– High quality machined aluminum mini housing
– Can be powered by batteries


Input impedance: 500K
Output impedance: 2K
Drive voltage: 8-12V
Power consumption: 60mA
S/N ratio:-96dBm
Size: 39Wx100Dx31H mm (excluding protruding parts)
47Wx100Dx48H mm (including protruding parts)
Weight: Approx. 160 grams(200 grams with batteries)
True bypass switching
*Batteries not included.