Keeley Java Boost No Longer Available

Guitar Treble Booster pedal with Mullard OC44 PNP Germanium Transistor, Variable Low Pass Filter, Level Control, 3-way Mode Switch, and True Bypass
Item ID: KJava

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Keeley Java Boost image 1
Keeley Java Boost image 1

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Keeley Java Boost
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Regular or Extra-crispy?

What is the Keeley Electronics Java Boost - the result of a Starbucks and Jamba Juice merger? Actually, the Java Boost is a '60-style treble booster that adds a gain stage in front of your already overdriven tube amp, pushing it over the top into saturated, harmonically rich distortion. Conjuring a mythical British box from the 1960s (the Dallas Rangemaster), the Java Boost employs the real article - a genuine Mullard OC44 germanium transistor. It's not an overdrive pedal, and when used with a crispy tube amp, you get results that are impossible to obtain any other way. If you overdrive your tube amp, the Keeley Java Boost is a must-have.

Keeley Electronics Java Boost Guitar Treble Booster at a Glance:
  • The misunderstood treble booster
  • Mullard OC44 germanium transistor onboard - for authentic '60s vibe
  • Boatloads of tone-shaping control
The misunderstood treble booster

The Keeley Java Boost doesn't boost treble, per se - nor does it sound particularly "trebly." Here's what it does: as frequencies go up, the signal gets increasingly boosted. Now, think of what this can do for your guitar sound. In the late 1960s - before guitar overdrive pedals - treble boosters were used to shove already overdriven tube amps over the cliff into thick, creamy distortion. To put this in perspective, guitar amps were not particularly distorted at the time, and there were no master volume controls. So guitarists resorted to devices such as the Dallas Rangemaster to add a gain stage and overdrive the front end of their amps, kicking them into high gear.

Mullard OC44 germanium transistor onboard - for authentic '60s vibe

The secret weapon inside the Keeley Electronics Java Boost is a Mullard OC44. We know, the name sounds like a piece of WWII British ordinance, but it's actually a rare germanium transistor that has been responsible for some of rock's most classic guitar tones. Keeley apparently has a supply of NOS (New Old Stock) OC44s, and is putting them to good use inside his superb guitar pedals.

Boatloads of tone-shaping control

Keeley's Java Boost is cleverly fitted with simple controls that enable you to shape your guitar sound precisely. The "Tone" dial is actually a variable lowpass filter. Under that, there's a three-position mini toggle that emphasizes highs, mids, or leaves the signal full-range. Used in conjunction with each other, these two controls give you an amazing amount of tone-sculpting capability. Lastly, there's a level control, which lets you choose how hard you want to punish your amp. All-in-all, a deceptively simple - but massively powerful - piece of kit. If you play guitar through a tube amp and use overdrive even a little, the Keeley Java Boost is a must-have.

Keeley Electronics Java Boost Guitar Treble Booster Features:
  • A modern Dallas Rangemaster circuit!
  • Use with an overdriven tube amp for classic singing sustain and rich harmonic overtones
  • Drive your tube amp over the top with syrupy overdrive
  • '60-style treble booster gives you that hard-to-come-by vintage crisp
  • Rare Mullard OC44 germanium transistor onboard - for authentic '60s vibe
  • 3 way Switched Treble-Booster - Locking 3 way switch so your setting is not moved.
  • Stock Vintage Rangemaster (Center), Mid-boost (Right), and Full Range (Left)
  • Metal film parts for low noise
Conjure the best of rock's classic tones with the Keeley Electronics' Java Boost!

Tech Specs

Manufacturer Part Number KJAVA

Customer Reviews

Based on 2 reviews
See also: Distortion Pedals, Keeley, Keeley Distortion, Overdrive, Boost & Fuzz