Mains electricity: The enemy within. You can't run your music setup without it, yet it's one of the main causes of equipment malfunctions.

IT'S A SAD, simple fact of life: if you're running a computer-based sequencing system in an onstage music situation, it will crash. Maybe not today, maybe not tomorrow, but someday soon. And you can bet it'll happen at just about the most embarrassing moment possible.

You won't be much safer if you're working with a computer-based system in a studio or at home either. Or if you're using a dedicated hardware-based system. There are more than enough true life horror stories about lost or corrupted data, crashed disks, blown power supplies and the like to make you feel a bit The Silence of the Lambs when putting the finishing touches to your 32-minute acid house opus in the bedroom.

All these problems are, of course, the work of some malevolent Norse god, piqued at the absence of Viking plainsong from the Gallup Top 40. Or rather they aren't, but it's a convenient way of explaining things away as you reboot and start from scratch once again. As always, the reality is far more dreary - all the hiccups in a processing system are actually caused by monkey-faced trolls that live in your MIDI ports and gobble up the information as it passes by...

Seriously, the real source of the problems is somewhat less exotic, but if you face up to it you can protect yourself against it fairly easily. But before you can do that, you need to identify the source of all this mayhem, and this is best achieved by using that good old scientific chestnut, the process of elimination. Possible answers come as follows: operator error - this is a ridiculous idea and not even worth considering here.

Software error - all proprietary sequencing programs have been pretty thoroughly tried and tested by truckloads of users and they don't always have the same problems. In any case, the random nature of the faults doesn't tie in with the cyclic way the software works.

Hardware error - all electronic equipment obeys what's known as the Bathtub Law, so-called because the curve produced if you plot product failures against time is the same shape as a sectional view of a bathtub. (Electronics boffs are a bit weird, y'know?) This basically says that equipment is quite likely to fail when brand spanking new because of manufacturing errors, and is also likely to fail when old and knackered because it's old and knackered. Apart from these two periods, electronic kit usually works perfectly well unless something nasty is actively done to it to make it not work.

That leaves us looking for some active, external variable - monkey-faced trolls! No, no, no, the problem is mains electricity.

OK, so you knew what the problem was anyway. But it's as well to compound the idea, just to make sure you don't overlook it and lay into your hardware next time something goes wrong. Your computer, your expanders, your samplers and all your other gear is fine. It's doing its best, don't go blaming it. It's just that it was only designed to operate under certain conditions, and very dodgy mains electricity is not one of those conditions.

Let's take a closer look at what dodgy mains is and how it can affect your gear. The electrical power delivered to your house, studio or concert hall by the electricity authorities is actually of relatively good quality in the UK. It's only "relatively" good because the apparatus used to generate and distribute the electricity is of archaic design and there are a number of faults inherent in the system. These faults are generally manifested as one or more of the following:

Sags - where the voltage periodically dips significantly below its 240 volts norm and then goes back up again.

Brownouts - where the voltage dips significantly below 240 volts and stays there.

Surges - where the voltage periodically rises significantly above 240 volts and then goes back down again.

"Your computer, your expanders, and your samplers are fine - it's just that they were designed to operate under certain conditions, and dodgy mains electricity is not one of those conditions."

Blackouts - where the power disappears altogether.

All these fluctuations occur frequently throughout the day as the authorities switch bits of their circuit on and off to cope with variations in demand (as weather conditions change, as the nation switches on its kettles after Brookside, as equipment in the grid malfunctions, and so on). There are loads of other glitches that appear in the mains lines, they're less important than the monsters above but they're still dangerous.

This all sounds fairly frightening, but things aren't quite as bad as they seem. All equipment that is plugged into the mains, including computers and other processing gear, is designed to be quite tolerant of fluctuations in the mains supply. Only the most extreme fluctuations will cause weirdness in a processing system, but this still happens often enough to be of concern. The real nightmares start when you actually start using the electricity that's delivered to you. Stage lighting, backline, power amps, effect processors, mixing desks, fluorescent lighting, air conditioning, heating, fridges, ovens, television sets and so on. These are the real villains; these are the monkey-faced trolls. Some appliances whack huge spikes and harmonics back into the mains to be circulated around everything connected to the mains circuit; others force the mains to supply really odd electrical waveforms to themselves and everything on the circuit; others switch on and off intermittently causing total disarray in the circuit, and combinations of these produce all sorts of strange shit. Again, most appliances are fairly tolerant of the smaller disturbances but electricity, well, it's a lot like life. Wild, unpredictable and bitchin' enough to completely fry your dongle.

THE MOST COMMON ailment caused by electrical disturbances is data corruption. Going back to basics, all a computer or sequencer or sampler or anything "digital" does is read and/or manipulate huge strings of "1s" and "0s" which are translated into "ons" and "offs" of electronic circuitry respectively. When a spike or voltage surge zaps through a processor all of the "offs" are turned into "ons" and, although a spike "might only be measured in thousandths of a second, it would still be capable of altering countless thousands of "off" signals. Depending on the information being processed at the time, the event may pass unnoticed. On the other hand it might result in altered characters, a spew of hieroglyphics, a disablement of a load or save command with subsequent loss of data or a complete system crash. Large spikes also stress the mains input side of your equipment, and will eventually mean that the power supply unit will need to be replaced. This is a very expensive exercise.

Large sags, brownouts and blackouts happen less frequently but we're still talking about weekly, if not daily, occurrences in most environments. These cause the system to pucker out through simple lack of juice and again have results ranging from mildly irritating to coronary inducing.

The severity of the problems encountered does vary from circumstance to circumstance and it is just about feasible that you might be unaffected by any major nasties - if you're luckier than Mr Lucky, the Lucky Luckster. But I don't think so. As with other forms of relaxation, it is certain suicide if you indulge in the pleasure of volatile, hi-tech music without recourse to adequate protective measures. So what's to be done?

There are a number of power protection units available from various sources, ranging in effectiveness from just about useful to being the absolute business. The device that you buy depends on the money you want to spend, which in turn depends on how much you value your equipment and, more important, the info stored on it. You're right - it's just like insurance.

Even if you don't think it's worth doing anything else, I'd strongly recommend that you dash out and buy one of the surge arresters which replace an ordinary 13A plug, and connect it to a suitable multi-socket outlet. It'll cost about £30 and will pay for itself many, many times over by filtering out a portion of the spike/surge spectrum.

If you can spend between £50 and £350 (depending on the size of your system) you can get a line conditioner/voltage stabiliser arrangement which filters out most of the nasties and maintains a steady voltage. This is OK as far as it goes but is really only a half-way house to the best solution - an Uninterruptible Power Supply (UPS). This is a shoebox-sized gadget which is connected between the mains and your processing system and contains a battery charger which keeps a set of internal batteries (similar to miniature car batteries) charged. Normally the load (your system) is connected to the mains via an internal filter, but in the event of a drastic fluctuation the batteries feed the load through an inverter which converts DC to a mains-style sinewave by a process very similar to PWM sample playing. This gives you ten or 20 minutes to finish what you're doing and save all your data gracefully. Prices start from about £150 for something suitable for a dedicated hardware rig or an Atari and S1000, through about £250 for a big Mac and a suite of samplers and upwards in increments to about a couple of grand for something suitable for a large-ish studio. It's the only real solution for sophisticated systems.

There you have it. You pays yer money... I'd say that if you're a studio, or hire company or you've got a large MIDI setup and you haven't got a UPS then you are running a very serious risk of losing your work (and your mind). If you're running any sequencer and/or sampler and you haven't got some protection then you're running a smaller risk, but you should think about protection.

Sadly, there doesn't seem to be power protection companies catering for the muso at the moment, so you're not going to find reliable information as readily as if you're shopping for a new mixing desk. In a moment of weakness I agreed to avail MT of my services, so if you're up against the monkey-faced trolls and need a friend, you can contact me via MT and I'll try to help you get the requisite protection for your setup. Keep it up.