Power protection. Power conditioners.
Do you need one? What does it do?
How can this SAVE your gear in a thunderstorm?
A lucrative niche has opened for the high end audio and video companies, and mass merchandisers have jumped onto the bandwagon at the speed of greed: POWER PROTECTION. You can spend/waste a few dollars for an ineffectual surge suppressor, or up to multi-thousands for much more sophisticated power filtration and stabilization devices.
Why do you need power protection?
Reason #1:
Lightning !!! If you are unlucky, it'll fry your gear. ...And scare the cat, who will race around the room like a bat on a sugar diet, knocking your precious heirlooms to the floor, detroying two hundred years of family history and wiping those Antique Hunter $$$ signs from your eyes.
By the way, is your new HDTV equipment COVERED by your home owner or renters insurance policy? Call your agent. It might require a separate listing or rider.
Reasons #2 and #3:
Surges and brownouts
Over-or-under voltage swings may damage sensitive gear or hinder its peak performance.
THE GRUNGE INVASIONWhy should AC power quality affect the sound or picture? High frequency noise is generated outside the house and inside it - say, by a computer or anything digital - or any industrial users on the power grid. That noise gets through a component's power supply and ends up in the audio or video. The noise isn't heard as NOISE, but as harshness, as less dynamic contrast, as grainy overlay, or seen as mosquitoes in the color, which isn't as vivid as it can be. Noise also gets into your system FROM your system - with each digital product polluting the others. It gets into the component's ground then makes it back to the AC line through the component's power cord.
How power protection works:There are several schemes, but basically, a good power protector will provide filtration to keep anything on the same circuit, including your digital gear, from polluting your other and non-digital gear. It'll contain fast acting circuitry which may sacrifice itself rather than your equipment, in the event of a serious surge or lightning strike. It'll hold your voltage steady.
Don't confuse power protection for your Home Theater with computer power protection. The home theater stuff is usually more sophisticated and costly. Sorry. Also, don't confuse this with UPS or Uninterruptable Power Supplies which are a computer safety system to allow battery power for continued operation for a limited time.
At the more complex leading edge of this technology (or voodoo, if you are born skeptical) are the following:
Special secret material which makes your power 'cleaner' - audio and video "veils" are said to be lifted, video colors and black seem deeper and less 'noisy.' Such material is said to have been a spin off of extremely low noise sonar work in submarine design.
The Power Regenerator:A box that takes AC (alternating current) power (from the wall), turns it into DC (direct current) power, like a battery, stripping all electrical 'noise' on the line caused by refrigerators, cell phone sites, air conditioners, etc. - including your neighbors' - and then rebuilds it to AC in perfect 60 cycle purity. (Also you have the capability of setting the frequency higher, which is said to improve things. You can also change the waveform from sine wave to partial square waves or mixtures of frequencies.)
Balanced power. Noise reduction.You asked for it, tech-head: In normal wiring there is one neutral wire which is always at (almost) ground potential, another wire which carries the 120V AC voltage and a separate safety ground wire. In balanced power there are two out-of-phase 60V lines rather than normal 120V and neutral. The voltage difference between those out of phase 60V lines is 120V, so the equipments will get full 120V between their power input pins. It's a 1:1 power isolation transformer with a center tap to ground, so that you have two legs of AC which are 180' out of phase with respect to one another (with respect to ground), so that your ground currents cancel out. The center tap is also situated as at the center of the output voltage swing. It's more efficient if the voltage and current swings are synchronized.
But, does it work? Many think so. I do too.
OPINIONIf I put thousands of hard earned dollars into my new home theater, and I lived in an area with heavy thunderstorms, I sure would (and have) put protection on my AC lines. But don't cheap out. Get ready to spend $500 or more. What they don't tell you: some power protection gear has circuitry that actually wears out over time. Will it be there when you need it? (Yes, there are units that don't degrade. No, they aren't $199.)
Great Advice:I think you need protection more than you need conditioning. However, you might borrow - and CERTAINLY CAN BUY with a 30 day return privilege - a power conditioner - and try it - to see if you think the improvement is worth the expense.
How to avoid the common expenses of "extras" and "add ons": An important warning which will save you money.
Warning!Many stores try to scare you into buying more than you plan when you start to buy... it's the old UPSELL. Would you like FRIES with that? Let's say you walk in with a budget of about $5000 for everything, and you find a receiver and a HDTV display and some speakers for just about $5,000. Then they'll try to sell you the stand (HIGH PROFIT ITEM), special wires (DON'T! Buy from a source with 30 day return for credit, but get used to your picture and sound BEFORE THAT), power protection (WAIT - research it) and the 'undercoating' of the electronics world...The Extended Warranty. (Check with your credit card company FIRST - you may AUTOMATICALLY get extended coverage. Get the terms and exclusions - you can always buy that extended coverage if you want it, later!)
Power Protection in the Home Theater - Use of Surge Suppressors to Guard Expensive Electronic Gear
By Andrew Ghigo
Surge Suppressors – A First Line of Defense All home theater equipment should be equipped with at least some form of surge protection. Surge suppressors represent the most basic form of power protection – a first line of defense for all sensitive electronic gear.
Keep in mind that a surge in the ac voltage or a lightning strike, could lead to disaster - turning expensive gear into a smoking heap of plastic and metal. Investing in a suitably rated surge protector is surely a lot cheaper than having to replace expensive home entertainment electronics. The large selection of suppressors available on the market at an even wider range of price levels can make the process of selecting an appropriate protection device far from simple. Many of these surge suppressors would look the same to a non-technical person - with almost nothing that distinguish the cheapest from the best. In their simplest form, surge suppressors often come as an inexpensive surge protected multiple-outlet power-strip. More expensive units would normally incorporate additional surge protected connections for the phone line and the coax TV input; some units include surge protected LAN connections as well. In this manner, anything that interconnects with your equipment would have to go first through the surge protection circuitry within the power-strip.
How Surge Suppressors Work
The basic operational principle behind surge suppressors is to clamp high transient voltages while absorbing this potentially destructive energy. This energy is then dissipated in the form of heat - thus protecting vulnerable circuit components and preventing system damage.
In the event that the surge lasts for several milliseconds, the process may also cause enough current to trip the house circuit breaker, or blow the equipment fuse, thus protecting your gear.
Surge suppressors usually make use of a mix of components to suppress voltage spikes on the line. However, the mostly used component in surge protection circuitry is the Metal Oxide Varistor (or MOV).
The MOV is not the only surge protection component – gas-tube surge arrestors, avalanche diodes (similar to power zener diodes), and reactive type passive circuitry using inductors and capacitors, all possess the desired electrical properties required to dampen a transient behavior.
None of these devices does represent the perfect surge suppressor. Some lack speed, while others – like avalanche diodes – though extremely fast acting, do have a limited energy absorption capacity. For this reason, commercial surge protection devices combine several of these technologies arranged in multiple stages, to prolong surge suppressor life and improve response times.
Surge Suppressor Ratings
This discussion will not be complete without highlighting a few of the most basic parameters that define the capabilities of a surge suppressor; these are the UL listing, voltage rating, peak surge current, and power handling. IEEE 1449 Underwriters Laboratories Listing: Referred to as ‘UL 1449’ or simply ‘UL listing’, represent a set of specifications that determine if a surge suppressor is safe during use.
Ensure that the selected surge suppressor is labeled as ‘UL-listed transient voltage surge suppressor (TVSS) 2nd edition’. A UL-listing as ‘power tap’ is not sufficient. A UL-listed TVSS does not imply that it will protect your equipment from surges, but rather that the surge protector is not likely to pose any personal hazard to you during use e.g. through electrocution, fire, etc.
Operating Voltage: The lower the voltage rating of a surge suppressor, the more effective protection the surge suppressor will provide, however the voltage rating has to be in line with the respective application. In particular, the chosen suppressor voltage rating should allow the normal peak AC voltage to exist across the line – this is 1.414 times higher than the specified RMS value.
Peak Surge Current: This represents the maximum transient current that the suppressor can handle during a surge. Joule Rating: Also referred to as ‘Energy rating’, this is a measurement of the energy absorption capability of the surge protection device. Typical values may vary from 500 to 3000 and over. The higher the joule rating, the better is the surge suppressor capability to absorb energy spikes on the line.
A Word of Caution
Designed properly, surge suppression devices can work over-and-over again, but... Do not take surge suppression devices for granted. Beware of cheaply made power line conditioners and other protection gear. Some surge suppressor components used in these devices are typically a one-time use only. This means that your system may end up completely unprotected after a surge.
Quality: The quality of a surge suppressor is reflected in the price of the protection device, but not only. Check the joule rating of the surge protector to get an indication of how much damaging energy the suppressor can handle. The bigger the joule rating is, the better. Keep in mind however that unlike the UL-1449 Listing, there is no standardized testing methodology to determine the energy rating of a surge suppressor. Hence, do not rely on the joule rating alone – look also at the built-up quality and in particular, at the product warranty on offer.
Warranty: In addition to the standard product warranty, some manufactures also offer a ‘Connected Equipment Product Warranty’. This is normally in the region of several tens of thousands of dollars. A longer product warranty period and a higher connected equipment warranty value reflect a higher level of confidence on part of the manufacturer that the surge suppressor can protect your expensive home theater gear. Try to go for surge suppressor devices that come with at least a 5-year product warranty period, and a minimum of $10,000 (preferably $25,000), connected equipment warranty.
Performance: The performance of surge suppressors degrades with each surge absorbed. The problem here is that the rate of degradation is totally unforeseen due to the unpredictable nature of the surge. Surge rise time, peak voltage, energy level, and duration, all have a varying effect on surge protection circuitry.
A surge may have a higher energy level than the suppressor can handle, leading to the destruction of the suppressor and zero protection against possible future surges. To minimize this risk, top-quality power protection gear would normally make use of over-rated components in protection circuitry - thus allowing multiple surges to take place without any damage to the equipment.
Surge Suppressors are not lightning protection devices: Surge suppressors can provide adequate protection from 'normal' surges on AC power lines. Protection against lightning strikes it is a completely different story. No surge suppressor device can offer you the required level of protection in this respect.
Personal safety: Ensure that your surge suppressor is clearly specified as UL listed Transient Voltage Suppressor (2nd edition). This will reduce the risk of personal harm from fire or electrocution especially during a surge. At the same time, keep in mind that a UL-listed device does not guarantee that it will protect your equipment.
Conclusion:
In reality, surge suppressors are just a first line of defense – they do not provide protection from damaging voltage fluctuations and noise on the line that can seriously degrade the performance of your AV gear.
Surge suppressors should form part of an overall power protection solution – the use of line conditioners and ac-regenerators coupled with an appropriately rated surge suppressor would surely provide a more comprehensive approach to protecting expensive electronic gear.
Obviously, there is a price to pay for power protection, but it is literally - an ounce of prevention that can save you a big headache down the road!
Andrew Ghigo – A Telecoms/Electronics engineer by profession, with specialization in digital switching and telecoms fraud management systems, editor and publisher of http://www.practical-home-theater-guide.com - a site dedicated to all home theater enthusiasts with the scope of serving as a comprehensive home theater guide to home theater systems, product reviews and home theater design.
This article is an excerpt from a series of articles appearing under the Power Protection section of the site. Topics covered include benefits of power protection in the home theater, power line conditioners, ac regenerators, and surge protection. There is also a 'before-you-buy' power protection checklist, and a short discussion on the possible use of inexpensive computer-grade uninterruptible power supplies, as part of a home theater power-protection solution.
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