Fuzz boxes: who needs them? Picasso never used a fuzzbox when he was painting The Electric Ladyland, did he?

They do, I admit, have their uses. Perhaps your amp lacks a master volume and you need to dirty up your sound a tad; or maybe you need that extra bit of clout to turn your guitar solos into real ear-rapers; or do you just want something to generate miasmas of white noise that cover up the gaps as your fingers limp feebly from fret to fret? Or are you of that degenerate type that likes to fuzz poor defenceless drum-machines? (It works wonders on a Dr Rhythm.)

Back in the old days, fuzz boxes were dead simple. They had a switch that went "clunk", and a knob (two if you were rich) that enabled you to adjust the sound from a deep fart-like kkkrrrr to a thin fart-like ffffffzzzzz. The Ross Distortion (£29) has moved away from these first principles: though it retains the two-knob configuration, the switch no longer goes clunk. The Ross is a very basic pedal, and no better than it should be at the price. We have dubbed it "harsh".

In the white heat of technological revolution, it soon became possible to add a third knob to the fuzz box. This innovation, often known as a tone control, helped the fuzz box to get closer to its original intention: emulating the sound of an overdriven valve, with a warm harmonic distortion. This is why second generation fuzz boxes are frequently called distortion pedals, and not because they make you screw your face up while playing with them.

Of the three-knob fuzzes currently available, I have been toying with the Arion Distortion (£34), the Boss Distortion (£69), the Ibanez Sonic Distortion (£53) and the Arion Overdrive (unfortunately initialled SOD-1, cost £34).

From the bottom, the Arion Overdrive offers least in terms of grinding buzz-saw noises. The usual Level, Tone and Distortion controls are supplemented here (as on the others in the Arion range) by a dual output, with the option of either stereo fuzz or fuzz plus straight signal.

Its sister pedal, the Arion Distortion offers roughly the same tonal range, with a little extra fuzz capability at the top end of the distortion range. All Arion footpedals come in hard light plastic cases that could suffer under the weight of an injudicious platform boot on stage, not to mention the lack of bulk to hold them firmly in place. They also share a strangely muted nasality when compared with the open-throated roar produced by Ibanez's Sonic Distortion, and Boss's equivalent.

The Ibanez comes in lime-green metal casing and offers, at a tweak of the tone control, the full gamut of fuzzy sounds from a Santana-like rounded zzzoooommm to the host-of-angry-hornets crackle and screech.

The Boss Distortion does the same, and a little bit more; but in a bright orange box. It's difficult to differentiate between two machines that are as similar as these, except by saying that the Boss offers a tiny amount more distortion. This gives a fraction more sustain — but just a fraction.

All the footpedals I looked at (with the exception of the Ross Distortion) are equipped with bright red LEDs that "indicate the status of the equipment"; this means that it glows when the effect is on, unless the battery is flat. They all (again excepting the Ross) have easy-access battery compartments, too, particularly the Arions.

The Star Wars technology of the computer age has had its effect on the humble old fuzz box, make no mistake: out there on the cutting edge of noise science, the research departments have already come up with the... four-knob fuzz box. Phew!

Yes, after the tone control, we have individual bass and treble facilities. Not that they all willingly admit to this: while Arion's Metal Master (£40) and the Boss Heavy Metal HM2 (£60) both have Level, Distortion, Low and High Frequency boost, the Ibanez Super Tube Screamer (£54) has the rather old-fashioned sounding Level, Drive, Tone, and Mid-Boost. Judging by the traditional operation of knobs (going from less at left, to more on the right), Ibanez's Mid-Boost is either back-to-front, or they have picked completely the wrong frequencies to boost. That complaint aside, the STS was actually my favourite of all the pedals as it did almost live up to its name. With the Drive at minimum and the tone around halfway it gave a passable imitation of a tired AC30. Un peu plus de welly, and it has a nicely toppy distortion that had me thinking of valves rattling in their sockets. And as for that peppermint-green metalflake casing...

The Heavy Metal and the Metal Master evidently have their target audience sussed — all Macho Blacks, with just a hint of Arrogant Orange on the Boss.

The Boss is widely held to be the boss; it's almost certainly the top-selling fuzz pedal this year, if not the number one effects unit. And it does the job, with a ridiculously wide range of tonal variation from the bass and treble controls. It makes little difference what guitar you squeeze through the HM2, as anything (Strats, Les Pauls, even Ricky 12-strings) ends up sounding like E Van Halen owned it.

I would not have believed it possible, but the Arion Metal Master makes a nastier noise than the Heavy Metal. This could theoretically be a good thing, but it isn't. The MM is just too horrid — even with the treble full off, I couldn't get rid of a horrible, flatulent, cloth-ripping sound. Turning it up drowned the wetter noise in an enormous welter of extraneous whistles, buzzes, and squeaks; no combination of settings could rid me of the impression that I was listening to the most horrendous roaring noise since the fall of Sodom. Not useful, particularly when fed through Arion's "Added Weediness" circuits.

There you have it: the more knobs, the better the fuzz box — quite simple really. But I'd still bet Django didn't use one when he was writing the bible...