Hornby Skewes Shatterbox

The Hornby Skewes Shatterbox is a 1960s British fuzz pedal that puts two effects in one box: the Zonk II fuzz and the Hornby Skewes Treble Booster. Fuzzboxes.org calls it "an early 'multi-effects' fuzz box that combined the Hornby Skewes Treble Booster with the Zonk II"¹². Two separate footswitches let a player run the boost alone, the fuzz alone, or both together, which in its day was an unusual amount of flexibility from a single box.

It was designed in 1966 by Wilsic Sound for John Hornby Skewes of Leeds³, and was reportedly shown for the first time at the Frankfurt Musikmesse trade fair in the spring of 1969¹. It was produced in exceptionally limited numbers² and originals are rare enough that most players who want the sound today build it from published layouts.

A Zonk fuzz and treble booster in one box

The Shatterbox is really two Hornby Skewes circuits sharing a chassis. Guitar FX Layouts describes it plainly: "the unit combines two effects; The JHS Zonk fuzz and a Treble Booster circuit"². Vintage Guitar gives the same account from the history side: Wilsic combined the Zonk circuitry with the Treble Boost to create the Shatterbox⁴. The fuzz side traces directly to the Zonk Machine family, specifically the Zonk Machine II, and the boost side to the Hornby Skewes Treble Booster, which started with a germanium transistor that was soon replaced by a silicon one⁵.

Fuzzboxes.org notes the Shatterbox used the same construction style as the Wilsic Sound Fuzz, and that it is likely Charlie Ramskir, the Wilsic man behind the original Zonk Machine I, was involved in its development too, though this is probable rather than confirmed¹.

Controls and switches

The control set is minimal, as was normal for the era:

An owner who opened an original 1960s unit found a few details that differ from the commonly circulated schematic: a 4k7 trimpot between the fuzz control pin 3 and chassis ground, an input resistor of 470k rather than the 27k shown in the layout, and two 125uF capacitors inside. The fuzz switch is a DPDT type but only one side is used, so it functions as SPDT².

History and versions

The design dates to 1966, credited to Wilsic Sound for John Hornby Skewes of Leeds³, though it was reportedly first shown publicly at the Frankfurt Musikmesse in spring 1969¹. Production appears to have continued into the 1970s: Fuzzboxes.org notes that date codes on the potentiometers of surviving Shatterboxes show the model was still in production by the early 1970s¹. The printed graphics on the enclosures were updated slightly between the stripboard and PCB eras¹.

The circuit existed in both PNP and NPN forms. Guitar FX Layouts published four stripboard layouts in April 2017: the original PNP version, an NPN version, and LED-equipped versions of each². Builders should note one caution from the same source: one builder reported he could not get the layout to work, writing "I could not get this to work (built the regular zonk ii today without incident). This one just motorboats"².

There was also a related pedal sold under another name. The Exel Shatterbox, sold by Barnes & Mullins, used the same idea in a compact die-cast aluminum enclosure rather than the original's bare-bones folded-steel box⁴⁶.

Where it was sold and how rare it is

The Shatterbox was advertised in the British press and clearly sold in Britain, where many of the originals remain. Surviving units have also been sighted in Canada, Finland (two units) and Belgium (one unit)¹. Guitar FX Layouts calls it "another stupid rare fuzz/booster made in the 60's" and says the original unit was produced in exceptionally limited numbers². For most players, a clone built from the published PNP or NPN layouts is the realistic way to hear what it does.

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