Skip to main content

ThorpyFX Heavy Water review

It’s time to go nuclear with a double dose of boost…

ThorpyFX Heavy Water review
(Image: © Future / Olly Curtis)

Our Verdict

The Heavy Water is one versatile dual boost. Use it to wallop the front end of your amp or as an always-on secret weapon, it's all gravy.


  • Two boosts of different character.
  • Practical EQ.
  • Huge amount of boost available.
  • Exemplary build quality.


  • Nothing here, folks.

ThorpyFX’s The Dane, a twin-footswich pedal featuring overdrive and boost, has many admirers but not all of them need a new overdrive

Consequently, after many requests to put just the boost side into a pedal in its own right, Thorpy has done just that. The result is the Heavy Water, which not only provides that exact same high-headroom clean boost but also pairs it with a second boost that features germanium diodes in its circuitry for a different character. 

Separate footswitches enable the two boosts to be used individually or together: the ‘Dane’ boost (RHS) running into the germanium boost (LHS). Both feature a knob to control the amount of boost plus another to adjust the low-end. 

Set at minimum, the clean boost brings in a small but definite boost that enhances the sound, immediately making our amp sound better without undue alteration of its tonal character. If you do want a bit of tonal shift, the Lows knob can add a warmth and thickness that’s ideal if you’re looking for a bit more body from your single coils. 

By the same token, rolling it back can make humbuckers a bit leaner, or could help focus the sound when hitting a drive pedal or boosting an already driven amp. 

There’s loads of gain available and higher levels will drive the cleanest of high-headroom amps into break-up. The germanium side of the pedal is more of the same but has extra grit for a raunchier boost.

Both boosts on together is capable of delivering a ridiculous amount of gain that will truly pummel your amp should you decide you need it, but there are plenty of options for them to be used together more subtly – perhaps a small amount of clean boost always on as a tone conditioner with the germanium side kicked in for solos. 


This is one of the most versatile boost pedals we’ve seen, capable of everything from always-on tone enhancement to kicking in a full-on screamfest. It’s a great candidate if you want a single pedal in front of your amp, but for ultimate flexibility pair it with your favourite drive pedal.


(Image credit: Future / Olly Curtis)
  • PRICE: £189
  • TYPE: Dual boost pedal FEATURES:  Buffered bypass CONTROLS: LHS Boost, LHS Lows, RHS Boost, RHS Lows, LHS bypass footswitch, RHS bypass footswitch 
  • CONNECTIONS: Standard input,  standard output 
  • POWER: 9V DC adaptor (not supplied)  
  • DIMENSIONS: 65 (w) x 125 (d) x 53mm (h)
  • CONTACT: ThorpyFX

The rivals

Image 1 of 3

(Image credit: Maxon)

Maxon Dual Booster DB10 – $190 / £145

The DB10 features two completely independent boost circuits in a single compact housing, each with its own input and output jacks: the Clean channel is a transparent boost, and the Vintage channel is based on a classic treble booster.

Image 2 of 3

(Image credit: Carl Martin)

Carl Martin Dual Injection – £99

Image 3 of 3

(Image credit: Suhr)

Suhr Dual Boost – $200 / £199

Suhr’s offering includes two independent boosts, each with its own Boost and Hi-Cut controls. There is only a single footswitch here, but you can switch from Boost 1 to Boost 2 by pressing and holding it for about a second.