The Keeley Java Boost

A Pro-Quality Treble Boost Pedal review
By Philip Snyder

Way back in the 1960's the choices for effects pedals were very limited compared to today's inundated market. One of the few companies building effects (primarily for guitar applications) was the Dallas-Arbiter company of Great Britain. Dallas-Arbiter is best known for their Fuzzface pedal used by Jimi Hendrix but they also offered a treble boost unit dubbed the Rangemaster. By the early 1970's guitarists such as Brian May, Tony Iommi, Eric Clapton and Ritchie Blackmore had made the Rangemaster essential elements of their rigs.


Fast forward to current day. With original Rangemasters going for $1,000.00+ (if you can even find one) Robert Keeley of Keeley Electronics decided that it was time he created a treble boost pedal of his own. With roots deep in the Rangemaster tradition, the Keeley Java Boost is a pedal worthy of the comparison. It is an accurate, germanium-based reproduction of the elusive Rangemaster right down to the impossible-to-find Mullard OC-44 and CV7003 (military spec) transistors (long since out of production). These NOS (New - Old Stock) parts coupled with Keeley's modern Rangemaster circuit create a very valuable and useful pedal all wrapped in a brilliant blue powder-coated shell with ber-cool coffee cup logo.

So what does this have to do with 12-string bass you ask? Well let me tell you, there is some serious presence in this little box!

The Java Boost is capable of several things that can all be applied to 12-string bass in one way or another. Typically the pedal is used to push an amp that is already driven just to the point of distortion into a creamy state of overdrive rich in natural harmonics. The best example of what this sounds like that I can think of would be during the breakdown at the end of Cheap Trick's version of "Ain't That A Shame" on the At Budokan record. Set correctly, this pedal easily simulates the boost you hear as the 12-string bass is brought up in the mix for its turn at bat. A touch of overdrive and a healthy serving of bad-ass delivered by a pissed-off gorilla. Any questions?

Early Java Boost

Another way the Java Boost can be used is to simply leave it on all the time and contour your sound around what it brings to the table - a little gain and a lot of clarity. This is my favorite use of the pedal. It's particularly good for 12's because it really isn't a full-on overdrive. Lots of over-the-counter overdrive pedals distort too much too soon to be useful with 12's, but the Java Boost is just that - boost. While it is not a clean boost (see the Keeley Katana pedal for that), the amount of gain that it delivers is much more suited to 12-string bass. It is particularly good for players who really want those octave strings to cut through the mix, whether all the time or just in certain moments.

For those players who are already running an overdrive or distortion unit of some kind into a single amp, putting the Java Boost in front of it in the signal path will allow you to reduce the amount of gain created by that unit. In doing this you can manipulate the level of gain and boost with the Java Boost thus expanding your distortion and tonal capabilities. If your rig is of the dual-amp design (most commonly one guitar amp and one bass amp for 12-string bassists) the Java Boost is most effective when run through the guitar amp side of the rig; smoothing the distortion and defining those incredibly important mids and highs. Once again, this is how I like it best - left on all the time.

Have you ever seen such tidy wiring?

The Java Boost is particularly effective with lower-wattage amps. You can push these amps harder without making your eardrums bleed. My current rig is a compact yet very effective setup consisting of a Crate BX-50 50-watt 1x12 bass combo and a vintage Marshall 5005 Lead 12 12-watt 1x10 guitar combo. For this review I ran my 12 through the following signal path:

1.  Keeley Compressor (set for minimal compression)

2.  Boss CE-3 Stereo Chorus (turned off - used as a signal splitter only) A better choice would have been the Keeley-made Framptone Amp Switcher pedal)
        2a.  Keeley Java Boost to Marshall Lead 12 guitar combo (set for mids and highs - just to the point of distortion)
        2b.  direct to Crate BX-50 bass combo (set for lows - just to the point of distortion)

With this setup I was able to achieve a wide range of tones and several levels of distortion from subtle, slightly driven tube-type gain to full-on growling thunder. The main difference I found between this unit and typical, mass-produced overdrives was clarity. Once you make the jump to high-quality, hand-crafted equipment made by true audiophiles and not just worker bees in large factories, you really begin to understand the difference between these units and the standard fare found at your local chain music store.

The Java Boost was equally useful when I ran through the bass amp alone. I set the amp just to the point of clipping with the tone controls as I normally have them. I played for a minute to allow my ears to become familiar with that sound. Then I turned on the Java Boost... WHOA! The distortion didn't go completely nuts as with some overdrives, but the presence was through the roof! I was able to quickly dial the pedal in and find a tone that I didn't think this amp was capable of. I ended up with the toggle set to full-range boost and with the Tone control at 10:00 and the Level control at 1:00 (once again running the Keeley Compressor in front). Bliss, sweet bliss.

The Java Boost features true-bypass circuitry, Switchcraft jacks, a stamped serial number, and of course a cool blue LED!  Keeley and crew are known for using the best possible components including metal film parts for low noise and expensive locking 3-way switches. The Java Boost also features a mini-toggle switch that allows you to select between three different ranges of tone; treble, mid, and full-range boost. This is where the Java Boost may surpass the original Rangemaster. Having these options virtually eliminates the chances of anyone not being able to put this unit to good use. As with the Keeley Compressor, the Java Boost has earned a permanent spot on my pedal board. I cannot make a stronger statement for it than that.

Java Boost

You can learn more about the Keeley Java Boost and all of the other fine pedals Robert Keeley and crew offer at Many thanks to Dusty Nelson, Artist Relations at Keeley Electronics for supplying the Java Boost pedal for review and for his interest in what we're doing here at Thanks Dusty!