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| EMagazine Volume 5 Issue 2 April / May 2000 |
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Power conditioners have come a long way in the last few years. It is clear that if protection for your equipment is the primary focus, then there are a number of excellent choices on the market today. If, however, you are also interested in picture quality and sound quality in your audio video system, then you should consider a more technologically advanced method of power conditioning if you would like to have all that is possible from your home theater investment. |
Power conditioners have been around for as long as household AC power has been available. Used primarily by industry, laboratories, and research facilities, power conditioning was not popularized for the home until the advent of the PC. It was the proliferation of personal computers that first raised the awareness of the home owner to the benefits of power line conditioning, which later manifested itself as an entire industry dedicated to producing power conditioners and protectors.
Following the popularity of inexpensive surge suppressors for the computer, the growing home power conditioning industry began to design and manufacture equipment targeted specifically for home stereo, and later, home theater.
Why condition?
What's wrong with our home's power that would cause us to invest in any form of
power conditioning?
1. Protection from surges and lightning.
2. Noise
3. Voltage fluctuations and distortion
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Perhaps the single biggest reason that anyone thinks of a power conditioner is for protection of their equipment. Certainly the home theater customer has typically invested thousand of dollars in their AV systems, and a surge in voltage or a lightning strike could spell disaster. Most commercially available power line conditioners include some form of protection, usually through a device called a MOV. A MOV (Metal Oxide Semiconductor) is an inexpensive part that is designed to create a short circuit across the line if the voltage fed to it is exceeded. The idea here is to draw enough current to trip the house circuit breaker, or the power conditioner's fuse, should a surge of high voltage be encountered, thus protecting your equipment. Designed properly, these MOV devices can work over and over again: but that is not usually the case. Beware of cheaply made power conditioners or protection devices, as their MOV elements are typically one time use only, leaving your system unprotected after a surge. Our company's products, for instance, use a huge MOV that is over rated for its output, thus allowing multiple surges to take place without any damage to our product or your equipment.
Lightning strikes are a different story. Fortunately they are rare, unfortunately, there are no commercially available systems that will offer 100% protection from a direct lightning strike on your home. In areas where lightning strikes are common, the savvy home owner may want to invest in an old fashioned grounded lightning rod on their roof.
Noise on the power line
The second most important reason for the inclusion of a power conditioner is the
elimination of noise from the AC line. Noise is created by radio stations,
television stations, cellular phones, and all manner of radiating electronics
prevalent in our modern society. Their reduction or elimination can have a
positive benefit to our audio video system's performance.
Most power conditioners use a filter to reduce these noises. A power line filter can be as simple as a $0.99 capacitor placed across the line, to a $1,000 AC regeneration device that creates new power in the home. The typical filter arrangement consists of a coil of wire (known as an inductor) and a capacitor. The impedance of the inductor increases with frequency, allowing the higher frequency noise components to be shunted off through the capacitor to ground. 90% of all power line conditioners use this approach. Their advantage is relatively low cost. Their disadvantage is limited reduction of noise. Yet another approach involves the use of an isolation transformer. This method of noise reduction is generally accepted as superior to the first method. It's advantages include better noise reduction, and the creation of balanced AC power (which is better for audio video equipment). It's disadvantage is higher cost, limited power delivery, and increased size, weight and mechanical noise. The third approach is a more recent development and represents the state of the art in power conditioning. It is know as AC regeneration. Basically, AC voltage from the wall socket is fed into the AC regenerator, which has an electronic equivalent of a power generator inside. Using the power from the wall, the generator creates completely new AC voltage that is virtually noise free. Our company, PS Audio, manufacturers three such devices in different sizes to meet smaller and larger power requirements of equipment. The advantages of AC regeneration include the complete elimination of any noise on the line, complete voltage regulation, balanced power, elimination of any distortion components, and full protection. The disadvantages are a higher cost, added heat, and increased size.
Voltage fluctuations and distortion
The third reason that people purchase power conditioners is to deal with
fluctuating voltages (higher and lower) and distortion of the AC power.
Unfortunately, these two problems have perhaps the biggest detrimental effect on
our audio and video systems, and are the least known and most poorly documented.
You read little of these problems, however, for good reason; virtually no power
line conditioner properly addresses these problem. Only an AC regeneration
device, such as a PS Audio Power Plant, can repair the AC line voltage.
As mentioned earlier, power conditioners for the most part fall into two categories; filters and line isolation transformers. Neither of these has any ability to increase or decrease the line voltage should it change, and none have the ability to repair a distorted AC voltage. There are a few conditioners today, that use a multiple power transformer tap technology, that can adjust for long term voltage fluctuations. While superior to having no control over the line voltage, they can only effect those fluctuations that occur slowly over time. Should any fluctuations occur quickly, these devices can offer no help.
Voltage fluctuations are a problem for any home theater setup, as large power amplifiers found in subwoofers, projectors, RPTV's, and multi-channel power amplifiers tend to create voltage fluctuations in your home's AC power. These low voltage fluctuations can be rather large, reducing your home's wall voltage from a nominal of 117 volts to as low as 100 volts when a loud passage of music, movie soundtrack, or bright and colorful picture via a projector is encountered. A drop of voltage of this magnitude means a dimmer picture for a projector, or a significant loss of power for an amplifier. For example, a 200 watt per channel amplifier will be able to output only 160 watts under these conditions. Further, line voltages in your home fluctuate sometimes as much as 5 volts depending on the time of day. Higher fluctuations can cause excessive heat and occasionally damage.
In conclusion
Power conditioners have come a long way in the last few years. It is clear
that if protection for your equipment is the primary focus, then there are a
number of excellent choices on the market today. If, however, you are also
interested in picture quality and sound quality in your audio video system, then
you should consider a more technologically advanced method of power conditioning
if you would like to have all that is possible from your home theater
investment.
For more information, visit PSAudio web site or contact them at 877-772-8340 within the United States, or 720-406-8946 outside the United States.
