There's no feeling quite like that moment when your guitar lead wraps itself into a firm reef knot around your ankles and you start to topple forward onto your nose, kneecaps and priceless 1923 Les Paul.

Once experienced, it's never forgotten, like free-fall parachuting (but with a somewhat more abrupt ending) or your first orgasm (but without one).

Of course that sort of thing doesn't happen to the pros. Along with their teams of roadies, heaps of spare gear and well-organised, neat stages they've almost invariably got one more advantage over us grubby paupers; wireless guitars.

That doesn't mean that your instrument tunes itself mid-set to the Home Service (although anyone who saw Spinal Tap won't be as easily convinced).

It does mean you have a little box — the transmitter — attached to your guitar, usually by being taped to your strap, and another slightly larger box — the receiver — on or near your amp.

Apart from the absence of cable, a good wireless system should act like an invisible but faithful lead; quiet, distortion-free, and generally transparent to the signal passing therein.

That's the theory. So what's the practice? Well, there's only one way to find out.

So in the fine old One Two tradition of launching ourselves blindly deep into the dag, we arranged a gig at the local dubious pub and, trusting completely to the three systems on test, strapped ourselves into our axes and rocked out. Or thereabouts.

The three that we put our reputations into the hands of were by Sennheiser, Toa and Trantec.

The former is an expensive (£787) German-built system of great sleekness and solidly constructed looks.

The second one, Toa's similarly smart brushed-aluminium attempt, has recently been dropped in price from £587 to £399 in response to market forces — in other words, the fact the cheap systems are starting to proliferate like rabbits.

And the third is one of these selfsame cheap systems. Trantec are a new all-British company (muffled cheers) who have put together a system at £299 which appears to do everything that the more expensive ones do at a much more sensible price.

Of course, there are others in the market; Nady and Countryman are just two of the top-end makes which are very good but so ridiculously priced that nobody can afford them unless they're in U2.

And I'll assume that you're not Dave Edge or the one whose name nobody can ever remember with the ridiculous blond Afro haircut, so here are the facts on the ones we doled out a hammering to at our live and fairly dangerous extravaganza.

For a start, what do the systems consist of?

Well, all had a small (roughly eight inches wide, two or so high) box with an aerial at the back and various sockets, controls, meters and so on.

Best on that front was the Toa, with a choice of several outputs including a separate 'monitor' jack output which meant you could put one signal into the PA and another at a separate level into your amp for onstage monitoring.

Simplest, however, was the Trantec, with merely LED lights for power and signal on and a jack output to the amp with a screwdriver-adjustable level control. The Sennheiser fell halfway between the two with one XLR socket out and a volume control, but also a headphone socket for some reason. Odd.

The important bit is the sound, though, as with most bits of gear. And as the man from Trantec said, "there's nothing to test, really. Either it works or it doesn't."

Well in the case of his device, it most certainly did. Quite simply, the quality was exactly what you'd expect from a good lead; no noise, no taxi drivers interrupting your best American Rock with their best Walthamstow English, and no microphonic clunks and bangs from the transmitter as it swung against your spine.

The range was pretty good, too. If you wanted to wander off down the road, go to the bog, or just walk off stage and order a pint during your Wilko Johnson rhythm bit, you could with no problems.

The plastic casing of both bits may get you thinking dubiously about their solidity, but it did have the advantage of being light; a hefty great lump of transmitter dangling about behind your ribs can do you a serious if you're too violent with the old swings and jumps.

One more point while we're talking Trantec — it takes a standard nine volt PP3 battery, of the sort that most guitarists seem to use to line the bottoms of their gig-bags, so there would be little problem getting hold of them, unlike the tiny penlight batteries used by both the other systems.

Sennheiser's pricey but smart-looking device was reasonably good, too; I did notice, however, a trace of radio interference once which was offputting and its range wasn't quite as long as the Trantec's; you could still get into the loo with no trouble but if you wanted to use a cubicle you might have problems...

As for the Toa, it was respectable in performance as a radio system, but the strange connector used on the transmitter meant that a special lead had to be made up; a lead which subsequently turned out to be faulty.

This would be a serious situation for most users because the tiny locking plug is a very unusual choice indeed for a musical device. Surely a standard plug could have been used?

As it turned out, this was a system which worked well in a technical way but was obviously built by technologists rather than musicians. The only fault was a dodgy lead but it did stop it being used at all; a shame for once the lead was mended at home later its performance seemed fine.

Anyway, back to the gig. There we were, spinning round in circles, jumping yards in the air, running into the adoring crowd, climbing up the PA; and all without any wires at all.

Both of the audience, we're told, enjoyed it very much.

Trantec Toa Sennheiser Wireless guitar systems: £787, £399 £299