Electro-Harmonix Bass Big Muff Pi

Electro-Harmonix's Big Muff Pi has been around since 1971; the late Cliff Burton, Metallica's original bassist, was a big fan. The bass version offers a classic fuzzy mire via the same controls as its guitar-orientated forebear. Three smooth-travelling black plastic dials include the self-explanatory Volume followed by Tone, which'll get you fat, soupy drive fully anti-clockwise (bassy) or a weedy, zingier offering at the opposite extremity. The final knob is Sustain, which adjusts both distortion intensity and how long the noise actually lasts.
The bass-tailored element is the mini toggle switch: Bass Boost (up) adds a low-end frequency boost to the distortion for fattening up treblier settings, Norm (centre) accesses the traditional Big Muff sound, and Dry mixes your clean signal with the distorted side. All this is neatly presented in a sturdy, green-faced aluminium case with red 'on' LED above the stomp switch and the added bonus of a 9V power supply in the box as standard.
Combining Tone and Sustain with the three toggle settings produces a wide range of options. Dialling both to nine o'clock in Boost or Norm mode induces a bassy crunch with a rubbery quality that's perfect for creating distorted grooves in the Hysteria vein. In Dry mode the pure note pokes its head through, tracked by a vicious-sounding shadow that creates a pseudo three-dimensional effect. Backing off Sustain to a minimal level here produces a decent approximation of Jack Bruce's Marshall-amped bass sound with Cream, while cranking it clockwise sounds fat and dark and hints at impending doom.
Rotating Tone to the treble side (clockwise) generates a fiery sound with a zingy, crunchy edge: it's very contemporary metal. Flicking the toggle to Norm and rotating the Tone to the bass side gives a result that's soupier and fractionally more polite, while dialling it clockwise gets gradually more aggressive – but the thinness of this sound makes it useful only for mindless shredding. Full Sustain here is akin to a volcanic eruption, and it's great fun. Bass Boost mode is more practical than Norm as whether you go for gurgling rumble, nasty-bastard snarl or the full OTT white-noise assault, you'll have more than enough bottom end.