Surge protectors and line conditioners in the mid-line?

February 1, 2005 7:12 AM

I just purchased a Mitsubishi WD-52525 DLP HDTV and the manual suggest that some problems might occur if a surge protector and AC line conditioner are not used. Any recommendations on satisfactory surge protectors and line conditioners (something in the mid-price range)? Also, could someone explain how a line conditioner works and why it is necessary?
posted by sharksandwich to technology (10 comments total)

The voltage coming down the line in your house is not exactly 120V, nor does it even keep a steady value, it varies a bit up and down. A line conditioner would be used to smooth out the voltage and keep it steady, and ideally at 120V. A surge protector normally does nothing, but if there is a large surge in current it will attempt to absorb it, throw a circuit breaker, and prevent damage downstream.
posted by RustyBrooks at 7:16 AM on February 1, 2005

if you have a noisy image - sudden interference when the fridge witches etc - then a line conditioner will reduce that, but there's no need for these things if you are happy with the picture as it is. you bought a domestic appliance and it should work with normal domestic supplies. they're just pushing you to buy more stuff.
posted by andrew cooke at 7:27 AM on February 1, 2005

No, do not install those things (unless they came free with the power bar or TV).

The usual line conditioner is generally nothing more than either a choke in line with your AC and possibly a capacitor to limit the output to 60 Hz (not more or less). A proper line conditioner would be a full blown 1:1 isolation transformer in addition to the above, but I don't expect that.

If the manufacturer expects you to purchase additional equipment before being able to operate what you bought, they need to write it on the outside of the box in a conspicuous spot. Imagine if you bought a flashlight and inside the manual it said "Requires type ZZ batteries, only available in 1950's electronics shops". You'd not just ask for your money back, you'd require it.

If the TV is damaged because of the lack of these parts (it should not be if it is CSA/UL/CE approved -- that should at least ensure a good power supply design) then it is the manufacturer's fault for not integrating them into the set.

Personally, I'd phone up the phone number in the Mitsubishi manual and give them a piece of my mind, but that's just me. The notion of requiring you to buy additional stuff not listed on the box is Ridiculous (with a capital R). Now, the idea of suggesting extras, that's not a problem. But to say you'll have problems without them? Give me a break.
posted by shepd at 9:18 AM on February 1, 2005

if you do want to hook up any tv/stereo/etc. equipment to a ups, try to get one that has a pure sine-wave output -- the square-wave output of cheaper ups is ok-ish for computers but not so good for a/v bits since it can introduce harmonics or distortion.

personally I would not bother unless your residence has really crappy power quality.
posted by dorian at 9:51 AM on February 1, 2005

The reason I am asking is that my home was built in the 40's and has older two-prong outlets (not grounded three prong). I haven't gotten around to changing the ones over in the downstairs unit which I occupy (tenants always get the good stuff first). At any rate, when larger appliances turn on and off (washer/dryer/AC), the light dims for a split second. I was wondering if this in any way affects the television. The BestBuy salesman seemed adamant about getting a high quality "home theater" surge protector, and the troubleshooting appendix references the AC conditioner as a possible solution to the set "resetting" itself. I was just wondering if I could head off an future problems by purchasing both of these items. I do understand the BestBuy drone was trying to add shit to increase my total, but it's hard to tell what I should believe and not believe.
posted by sharksandwich at 9:59 AM on February 1, 2005

Tripp Lite has some reasonably priced line conditioners (with $xx,000 guarantees) and they're probably what I'd buy in such a situation. And here's the PriceGrabber page for line conditioners.
posted by Alex Handcoding at 10:11 AM on February 1, 2005

If you have ungrounded outlets and you don't want to run ground wire, replace the outlets with GFCI outlets. The design of these will give you (almost) the same protection a fully grounded design would give you, to the point that in most all areas it is within code to "cheat" the ground in this manner safely.

At any rate, when larger appliances turn on and off (washer/dryer/AC), the light dims for a split second.

This is normal, especially for lower amperage service (say, 40 amp service). Your TV's power supply should be able to cope with this either by turning off if the brownout is too severe, or just riding it through if it isn't.

The BestBuy salesman seemed adamant about getting a high quality "home theater" surge protector

ROFL. I bet it wasn't even metal. Most all of the better-than-basic surge protectors implement MOVs. MOVs are designed to short voltage spikes (this is ok). After doing this too many times MOVs short out, and *should* melt themselves into an open. Of course, if that happens, they don't give you protection anymore. The life of an MOV will depend on your power, but 2 or 3 years isn't unreasonable.

MOVs cost about $0.10 in bulk, and a fully protected outlet requires 3. An electrician should be able to demonstrate how you can integrate them into your outlet, if you desire, rather than paying lots of money for expensive power bars. [Hint: One goes between Hot and Neutral, another Hot and Ground, the last Neutral and Ground].

A really expensive AC conditioner (like $200 - $500+) should include circuitry to automatically adjust the transformer output to give you 120 volts no matter what the input is (as long as it is within range). But for $500 you could probably get your electrics replaced. And best buy has NEVER sold any sort of "power conditioner" that would do that.

The trick a consumer to use to gauge the quality of the line conditioner would be to weigh it. SInce a decent transformer will be HEAVY (oh, say 20 - 50 lbs for what you are looking at) if you are picking it up with one hand it's absolute garbage.

I do understand the BestBuy drone was trying to add shit to increase my total, but it's hard to tell what I should believe and not believe.

Well, believe this, accessory markup is between 2500% - 5000% at Best Buy. I'm not making that up -- I buy premade network cables in bulk for about $1 each. The local Best Buy sells the same cables for $50 each.

The Tripp Lite conditioners Alex Hancoding linked are good and would actually adjust the voltage. But why not just pay an electrician to fix up your place instead? :-)
posted by shepd at 10:48 AM on February 1, 2005

sharksandwich: At any rate, when larger appliances turn on and off (washer/dryer/AC), the light dims for a split second.

A line conditioner won't help with power dips anyway. It will remove noise though, so if the vacuum in the rental suite ruins your movies then a line conditioner might help.

I totally agree with shepd (with fewer words :P). If the thing doesn't provide basic functionality out of the box it is a bad product, it isn't your electricity. On the other hand, you may need to jump through any number of hoops to get peak performance out of it.

Tweaking to get the best possible performance should be addressed over time, not up front when you buy the thing. It might require any number of added or improved components and other measures (I'm audio, not video, so I will leave specifics to others).
posted by Chuckles at 11:55 AM on February 1, 2005

I have a couple of Panamax surge protectors on my home entertainment systems. My reason for buying these was for lightning strike protection, as Panamax has a pretty decent warranty.

If you browse through the rest of the Panamax site, you'll see they also carry higher end line conditioning/UPS equipment.

Generally, I agree with what shepd said above -- for what you pay for high end home theater equipment, you should expect a fairly robust power supply that can handle minor fluctuations in line voltage.
posted by SteveInMaine at 12:10 PM on February 1, 2005

shepd's pretty much on-the-mark.

manual suggest that some problems might occur if a surge protector and AC line conditioner are not used

A real line conditioner is pure overkill, as everyone's pointed out. A surge protector, on the other hand, is cheap as hell. Most come built-in to any power strip you'll buy. It's just a fuse. I don't know what they're rated for... probably a couple of amps. Anything coming down the line, whether it be from power company surge (unlikely) to lightning strike (possible... but never happened to me yet) will be stopped by your cheap-o power strip, and not your expensive HDTV power supply.

But like the shepinator said, you can install ground-fault protection outlets in the wall for peanuts, and then you don't have to keep buying a new power strip every time the circuit pops. If the Best Buy guy really wanted to help you out, he should have recommended their financing option where they move you to a place that doesn't have a lot of rain.
posted by Civil_Disobedient at 7:49 AM on February 2, 2005