The HD GuruÃ¢â‚¬â„¢s readers have asked for the real story on power line conditioners. Are they really needed with an HDTV? Do they provide a sharper picture as some salesmen claim? How well do they protect the TV in case of a lightening strike or other electrical spike? What about surge protectors and uninterruptible power supplies (UPS)? The HD Guru responds.
Potential Problems With Your AC Power
In the United States the alternating current (AC) sent from your electric company should be delivered to your home at a steady rate of 120 volts at 60 cycles per second. In some parts of the US, there are variations, resulting in voltages that are either too high or too low. Sometimes interruptions cut the power altogether. Delivery of too much power is called a voltage surge; too little, a voltage droop or sag. Electrical storms can deliver lightening strikes, which can produce catastrophic voltage surges capable of destroying the power supplies of all the electronics plugged into the system, whether theyÃ¢â‚¬â„¢re powered up or not. Air conditioner and refrigerator motors powering on and off can also cause momentary voltage fluctuations. Another potential power problem is electrical interference caused by industrial grade electrical equipment operating nearby as would be found in a factory. Your homeÃ¢â‚¬â„¢s wiring may also pick up electrical line interference or radio frequency interference (RFI) caused by, among other things, broadcast transmitters located in your vicinity.
Power Fluctuation Symptoms
Fluctuating voltages can cause lights to brighten and dim. TV, lights and other electrical devices may momentarily shut off due to total voltage dropouts. Radio frequency interference can create hum and/or video noise bars and static.
What Line Conditioners CanÃ¢â‚¬â„¢t Do
Power conditioners canÃ¢â‚¬â„¢t give your digital HDTV a sharper picture or better color, regardless of display technology, whether plasma, LCD, DLP, SXRD, or DILA rear projection. Period. Resolution is, by definition fixed, and so cannot be increased. If a salesman tells you otherwise, ask why are there no power conditioners connected to the dozens of TVs on display. All HDTVs have internal power supplies designed to filter and transform the incoming AC to voltages necessary for the setÃ¢â‚¬â„¢s operational needs. These built-in power supplies do a great job, and are designed to accept a fairly wide range of line voltages. Can a power conditioner clean up heavy interference in your power line? Yes, but most of the time they are simply not necessary and will be of no use because the vast majority of households are free of electrical interference.
What You Need To Protect Your Television
While power conditioners cannot improve your picture, a surge protector can protect your set in the event of a power surge. WhatÃ¢â‚¬â„¢s needed depends on the display and the amount of protection you can afford. For LCDs and plasmas the HD Guru suggests a surge protector at the very minimum. According to experts, the rating should be at least 360 joules. These are very inexpensive, with prices starting at under $20. For lamp driven devices such as microdisplay front and rear projectors, including LCOS (Sony SXRD and JVC DiLA), DLP and LCD, you should purchase an uninterruptible power supplies (UPS). The HD Guru also recommends using the UPS with digital video recorders (DVRs like TiVo). A UPS will prevent the lampÃ¢â‚¬â„¢s cooling fan motor (or hard drive in the DVR) from shutting off during a power failure. You need just enough battery power to cool off the projector to prevent premature lamp failure or a DVRÃ¢â‚¬â„¢s power down. 10 minutes worth of battery back up is more than sufficient. Virtually all UPS units also have built-in surge protection.
UPSsÃ¢â‚¬â„¢ are either on-line or off-line designs. The on-lines are best because they actively filter and convert AC wall power into DC (Direct Current) to charge the battery, while simultaneously converting the DC back to AC to run your HDTV or DVR. In addition to offering excellent line conditioning, on-line UPS systems provide surge protection. Because itÃ¢â‚¬â„¢s Ã¢â‚¬Å“on-lineÃ¢â‚¬Â there is no voltage drop when the AC power fails. The switch to battery backup is seamless.
The Tripp-Lite SU750XL is a good on-line UPS. Rated at 750VA, it will run a 500-watt load for about 10 minutes, which is plenty of time to cool off the lamp in any projector or properly shut down a TiVo. While it retails for $449, a quick internet search found it for $288.93 + shipping.
Depending upon capacity off-line UPS prices start at around $40. Because the AC in/out circuitry is not coupled to the output thereÃ¢â‚¬â„¢s around a 1-millisecond switch between line current and battery power. Virtually all have built-in surge protection and many of the mid size and larger one also have line conditioners.
Bottom line? Instead of selecting a line conditioner with surge protection, which can cost up to $500 or more, get first-rate protection that includes surge and battery backup plus top quality line conditioning, for under $300 by purchasing an on-line UPS. For under $100 you can be protected from the most common surge and short-term power loss problems with a UPS with surge protection combo.
Copyright 2006 HD GuruSM all rights reserved