Understanding Subtle Electrical Fluctuations Affecting A/V Performance

These days, it's likely anyone shopping for electronics has at least seen a surge protector and has been told they ought to unplug their computer during a thunderstorm. But while the destructive nature of a lightning strike is commonly understood, the detrimental effects of more subtle electrical fluctuations are less well known. This makes power, as a basic system component, a tougher concept for the custom A/V integrator to introduce than the differences in quality of more visible parts of a home theater or stereo system.
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These days, it's likely anyone shopping for electronics has at least seen a surge protector and has been told they ought to unplug their computer during a thunderstorm. But while the destructive nature of a lightning strike is commonly understood, the detrimental effects of more subtle electrical fluctuations are less well known. This makes power, as a basic system component, a tougher concept for the custom A/V integrator to introduce than the differences in quality of more visible parts of a home theater or stereo system.

For the most part, consumers understand that when they spend more on a screen or speakers, they are paying for better construction and greater precision in engineering, which is reflected in picture and sound quality. Similarly, it is easier to see, at a cursory glance, how high end wires and cables improve those expensive components. Yet at the same time, many hold the belief that simply putting those fancier parts of it) today and years from now.

A good way to start is addressing the nature of power supply. Our electrical grids, while miracles of design, are examples of engineering on a huge scale; they are full of distortion that does not affect their performance on a macro-level.

That same distortion, while appearing minor from far away, can have disastrous impact on individual systems. Utility grid switching and sources closer to home-refrigerators, copiers and elevators-constantly disrupt electrical flow as their operation requires frequent changes in power-consumption. The resulting choppiness, or "noise," is passed on to a surrounding community often unaware of the consequences. The effects are felt in the long and short term.

Power spikes and surges, in individual occurrences, over extend power capacity for only a fraction of a second but, when repeated over time, can erode wires, chips and microproces together should provide the audio/video experience they've dreamed of, even when powered by the same wall-outlet as their coffee machine.

Clarifying the effects of running electrical appliances on unfiltered power is beneficial to the custom A/V integrator for many reasons; meeting customer expectations may have the furthes treaching effects. After purchasing a home theater system, for example, the customer is simply anticipating a satisfying movie experience. While a warranty may hold a dealer or installer responsible for some aspects of product performance, they cannot be held accountable for fluctuations in the local electrical environment over time. Regardless, they can receive a customer's blame for dissatisfaction incurred when parts break down for that reason, and a bad story is more likely to be passed on when the subject arises. It is then critical to communicate how those fluctuations affect their theater system (and their experience sors beyond use.

Audio/video signals and data can also be corrupted when subjected to erratic electrical supply and in a much shorter time frame. How many war stories have been passed around concerning disappearing computer files and crashing hard drives? Unfiltered power can be the overlooked culprit for such hassles. Leading customers to consider these examples in terms of front-end maintenance is another strategy in categorizing conditioned power as an essential ingredient of electronic systems.

In exploring and comparing individual power-products, there are a number of design varieties and a range of quality to consider. Surgeprotectors-like the basic power strip-utilize a couple basic designs: parallel and series circuits.

Parallel circuit protectors keep electrical overflow from ever reaching equipment. Metal-oxide varistors and gas discharge arrestors in parallel circuits react much like a water pressure valve: when voltage reaches a harmful level, they open up to rechannel it back through the ground wire.

Rather than divert electricity to another line, series circuit protectors slow its trip through a hot wire by absorbing power then gradually releasing it. Some say this method is faster than a parallel circuit, because it doesn't simply redirect a surge to the ground wire. Regardless of the circuit type, the basic surge protector is generally considered a starting point for power protection and should not be relied upon to cover expensive systems.

Surge stations are somewhat larger hubs with some added features like inputs for phone or cable lines, which are subject to surges like any other wire. Like breakers by the electrical meter, many versions contain their own fuse, which burns out to interrupt the circuit. Often, noise-filtration is limited to an electromagnetic coil that smoothes current variations passing through it.

Generally, power strips and surge stations are intended for personal computers and it is a good idea to consider them a basic component

of such appliances. Stronger and more reliable insurance than a surge protector is available in the uninterruptible power supply. These offer surge protection but also include noise-filtration capabilities far more intelligent than the common choke coil. The ability to sense and correct smaller power supply variations creates optimal conditions for operation of home-electronics, which extends their life. UPSs also contain batteries that will activate in a blackout to allow for safe appliance shutdown. They exist in models that can handle a single home theater or desktop computer or the power-main load of an entire business. Some contain batteries that last up to eight hours. Because UPSs are more expensive, it is still wise to use a surge protector to keep the cost of repair or replacement at a minimum when a UPS-damaging surge occurs.

Deciding on the right level of protection depends on how much equipment must be covered and your willingness to risk subjecting it to damage over time. In judging quality, look for clamping voltage, energy absorption and response time. Clamping voltage indicates when a parallel relationship between a buyer and seller. That satisfaction hinges on the presence of the right conditions for operation, which are assured by effective power conditioning. The benefits of power products, then, extend to a seller when the equipment they stand behind performs as predicted.

Concern for personal well being and sound product knowledge is a springboard for building customer trust. Associating the positive sales experience with the satisfaction a customer feels in the end, is the ultimate tool in creating a lasting circuit will take effect and should be no greater than 400V. The absorption rate tells how much energy can be absorbed before protection fails.

Basic rates start at 200 to 400 joules (watts per second) with better protection coming at 600 joules and higher. Spikes and surges usually only last a few billionths of a second so an effective response time is less than one nanosecond. Explaining these characteristics is central to putting into perspective the importance of avoiding inferior power products. Lower-end protection means a lower bill short-term, but might provide little more than the equivalent of an extension cord and false peace-of-mind to the consumer. In fact, customers should understand that choosing a poor design can do more than fail to prevent the loss of data or a nice receiver. Inferior fuses and wires can, in fact, combust trying to take on large surges, creating a serious safety hazard.

Product reliability is something consumers and custom integrators both want. The dealer/installer can expend less maintenance labor on too many individual products sold, increasing profit margin, while the buyer is connected to the satisfying product experience they deserve after making a purchase. This effect results in referrals being more likely, which also increases profit margin. Meanwhile, all of these benefits follow the immediate increase in profit yielded when the dealer adds power conditioners to a sale. While this is true, illustrating some of the above concepts should help dissolve the notion that power conditioning is a concept that was created merely for the chance at an upsell.

Bob Smith is vice president of sales and product development at Panamax Inc., in Petaluma, California.

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