Review: ThorpyFX Heavy Water

Based on the boosting side of The Dane overdrive/booster pedal, ThorpyFX’s latest bombproof box is compact in size, but still lets you give ’em both barrels.

ThorpyFX Heavy Water
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Review Overview

Our rating


Our verdict

Top boost, fat boost or both at once: a clever, space-efficient solution.

Some people just don’t want an easy life. Faced with requests to turn the high-headroom boost circuit from the ThorpyFX Dane into a standalone pedal, Adrian Thorpe could have simply whipped out his hacksaw and created a two-knob tone machine. Instead, he’s come up with the Heavy Water, a dual booster in a compact enclosure that offers a whole range of level-lifting options.

The right half of this unit is that Dane-derived clean boost, with a knob for output level and another for ‘lows’ – allowing you to thin things out or fatten them up as required. But the left side is a little different: it has the same controls, but uses germanium diodes for a grittier boost.

The good news is you can tap-dance between the two circuits or, if the front end of your amp has been really naughty and needs to be spanked, run both at the same time. The short distance between the two footswitches means this option should be easy enough to engage from bypass, unless you’re wearing the world’s skinniest winkle-pickers.

ThorpyFX Heavy Water

It is a compact enclosure, but feels no less solid than this maker’s heavier ordnance, with the usual metal side panels – this time in a rich aquatic blue – protecting the controls from knocks. Ex-Army officer Adrian loves his military references, of course; if you’re wondering about the significance of this pedal’s name, search Wikipedia for ‘heavy water sabotage’… or even better, take the afternoon off and watch The Heroes Of Telemark.

In use

ThorpyFX is down with the current trend for making pedals mains-only, and there’s no battery compartment in this unit. So we start the test with a Telecaster, a 30-watt tweed combo and a good-quality power supply. It takes only the lightest push from the clean boost circuit to tip that amp into full-on overdrive – and with the lows control at midday, it’s every bit as pure and transparent as we remember from the right-hand side of The Dane.

If you’re not after a flat full-frequency boost, there’s plenty of tone-sculpting power available. A twist to the right thickens things up for as much whoomph as your amp can handle, while winding it down brings a leaner sound with more space for the treble and upper mids to cut through, Rangemaster-style.

ThorpyFX Heavy Water

There isn’t a huge change in sound when we switch to the germanium circuit, but you can feel the drop in headroom; and while the front end of the amp is still doing most of the overdriving work, there does seem to be a touch more grind on this side of the pedal.

In truth, though, the inherent differences between the Heavy Water’s two circuits are not that important – what’s key is the way you can set those tone controls for a warming effect on one side and a raspy treble boost on the other. That’s giving you two very different kinds of lift for different musical needs… with the supremely powerful ‘both’ option waiting to be deployed when you need it.

Key Features

  • PRICE £189
  • DESCRIPTION Dual boost pedal. Made in UK
  • CONTROLS Boost 1 level and lows, boost 2 level and lows
  • FEATURES True bypass, powered by 9V mains supply only (not supplied)
  • DIMENSIONS 125 x 65 x 53mm
  • CONTACT thorpyfx.com

Like this? Try these

Xotic RC Booster V2 £188, TwinStomp Booster £159, Maxon DB10 Dual Booster £145

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