Power Protection: How to Choose
|You can find power protection components to accommodate just about any system.|
For a lot of folks, power protection means plugging everything into an inexpensive power strip equipped with a circuit breaker. While that may be adequate for some electronic devices, general purpose power strips usually won't fully protect sensitive audio/video components from damaging power spikes. And they seldom filter out the everyday electronic interference from your home's electrical wiring, phone line, and cable TV connections that can hurt your system's performance.
Power protection components come with a variety of options to meet the specialized needs of various systems. In this article, we'll explain those options. We've also put together a simple list to help you make sure the power protector you're considering has the right features for your system's needs.
Why do I need power protection, anyway?
You or someone you know have probably lost a TV or computer to a power surge during a thunderstorm. Preventing that kind of damage is a big part of what power protection does. After all, unplugging your TV during a storm may not be enough; if your cable box or satellite receivers remain connected, you've left a "back door" open for that lightning strike.
Less dramatic — though more common — is the damage done to audio/video systems by minor fluctuations in AC power, sometimes called "brown outs." And electromagnetic interference and radio frequency interference generated either by other devices in the home (like vacuum cleaners and blenders) or sources outside it (like nearby power lines or radio towers) can also impair your system's performance.
Inexpensive power strips simply aren't designed to offer that level of protection. They normally just break the connection if too much electricity comes through the line. And even there, cheap strips can fall down on the job. Because general purpose power strips often have higher tolerances than expensive audio/video equipment, a surge that could damage your components could pass through the strip because its voltage is below the level required to trip the circuit breaker.
To select the right power protection unit, you should consider the components it will be connected to — both now and in the foreseeable future. This can help you select a unit that provides an appropriate level of protection for your system.
Lightning strikes or power company overloads can create surges that could fry your gear in less than a second. If all your audio/video gear is plugged into a surge protector with AC outlets, you might think your system is safe. But these power spikes can also enter your home through your phone line, your cable TV line, or the wire that connects your satellite receiver to your outside dish. You'll want to make sure the power protection device you choose can accommodate all of the lines that connect to your system.
Surge protectors sacrifice themselves to save your equipment. They're designed to be the weakest link in the chain from the AC wall outlet to your equipment, and they include circuit breakers or fuses that immediately sever the connection when a large electrical spike hits.
Many surge protectors can also sense whether or not your home's wiring is properly grounded, and will alert you if a fault is detected. Improper grounding is often a source of audible low-level hum coming through your speakers.
Better quality surge protectors usually carry warranties that cover damage to connected equipment if they fail to contain a power spike.
Electromagnetic and radio frequency interference (EMI and RFI) won't fry your A/V gear, but they can limit its performance. Devices with digital inputs and outputs, such as Blu-ray players, receivers and LCD and plasma TVs, can be especially susceptible to "dirty power."
- EMI is caused by an electromagnetic field generated close to your system. Sometimes it can be contained in the current that comes into your home. A washing machine, vacuum cleaner, or blender can add a loud buzzing or a low hum to your audio system. EMI can also affect the quality of your TV picture in the form of "snow" or overall reduced clarity.
- RFI results from radio waves that can be generated by radio stations, microwaves, cell phones, lawn mowers, and many other sources. These interference patterns often originate a great distance from your home, and can be heard as clicks and pops. Your home's electrical circuitry can actually act as a crude antenna, sending RF signals through your system's power cords and into your gear. Sometimes cell phone conversations or nearby radio transmissions can even be heard through your system's speakers. RFI can also interfere with your TV's picture, dulling image details and washing out contrast.
A power protection component with line conditioning can remove most of this interference, allowing your system to perform at its full potential.
|An AC line conditioner with voltage regulation ensures stable power for the components you plug into it. ([Furman SPR20i shown)|
As electricity demands change throughout the day and night, the AC line voltage in your home swells and sags, and these fluctuations can limit your system's performance, and may even reduce the lifespan of your audio/video gear. For example, when voltage is low, the power supplies in components require more current, and that can generate heat, which is harmful over the long term.
A line conditioner with voltage regulation stabilizes the voltage it sends to the components that are plugged into it, keeping voltage within a narrow range. Voltage regulation helps ensure that high-performance equipment — whether it's audio components, high-end Blu-ray players, or flat-panel HDTVs — will perform at its best.
Heavy usage elsewhere on the line, brownouts, and accumulated line noise can all affect the power coming into your house, sending an irregularly fluctuating current into your gear. High-performance audio/video components are extremely sensitive to these changes. Power regeneration is the ultimate solution for smoothing out these irregularities.
Rather than just filtering your house current and passing it on to your gear like a conventional line conditioner, a power regenerator uses it to create its own power to send to your equipment. Incoming AC (alternating current) is converted to DC (direct current) to strip out electronic noise. The DC current is then regenerated perfect AC through circuitry that tightly controls the power flow, eliminating as much variation as possible. This regenerated AC power has virtually none of the noise or fluctuation of the original current, ensuring that your system gets clean, consistent power.
|UPS units can keep your gear on when the power goes out, so you can shut it off safely. (Panamax MB1000 shown)|
Uninterruptible power supply (UPS)
If you've ever lost work on your computer when the power suddenly cuts out, then you can appreciate the value of an uninterruptible power supply (UPS). UPS components contain internal batteries that provide power to your equipment during temporary power outages. Typically, a UPS can provide power for multiple components for a few minutes — long enough to ride out short blackouts or to save your work and shut down your system properly during prolonged outages.
Along with preventing lost data, a UPS can help extend the life of your gear. Many audio/video components are stressed by improper shutdown, which affects their performance and may shorten their operational lives.
Also, a UPS can prevent the loss of personalized settings in your audio/video components, such as channel programming with your satellite receiver, TV, or cable box. This is helpful for components that rely on an internal clock, such as a DVR or VCR.
Uninterrupted power is especially important for rear-projection TVs and projectors. These displays use an expensive high-powered bulb to illuminate the picture. Because this bulb gets very hot, an internal fan runs for several minutes after the TV is turned off to cool the bulb down slowly and safely. Plugging your projector into a UPS allows the cooling fan to run even if the power goes out suddenly, extending the life of the bulb.
Additional features to look for
Your power protection component can offer benefits beyond surge protection and line conditioning. More advanced features include:
- Sequential outlet turn-on — First sends power to your playback components, like a Blu-ray player or cable box, and then to your receiver or amplifier after a brief delay. This eliminates the infamous amplifier turn-on "thump," which can damage your speakers.
- Offset outlets for AC adapters — The bulky AC adapters that come with small devices like rechargers and game consoles requires only one outlet. But when plugged in, they can fully or partially cover the adjacent outlet, preventing its use. Offset outlets place additional space between the plugs to accommodate these larger "wall warts." (Offset outlets are more common on strip-type surge protectors than component-type models.)
- Out-of-the-way mounting options — Some power protection units include hardware for mounting on a wall or a component rack.
- Additional phone line connection — Some components require a connection to your phone line, such as a TiVo® recorder or satellite TV box. Many people don't realize that electricity can travel through a phone line as well as a power cord, and so often leave this "back door" open for catastrophic power spikes.
- Isolated outlets for digital sources — Reduces the high-frequency noise generated by digital equipment, such as DVD or Blu-ray players and flat-panel TVs. The outlets are arranged in isolated banks — one for digital components, and the other for analog audio and video components, like receivers and amplifiers. This keeps noise generated by the digital components from leaking back and interfering with the analog gear.