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Hi guys. I just finished repairing a receiver which I think was the victim of some power surges. (My parents' plasma went down at around the same time with three fried boards, and they live two blocks away. Also, when my parents went to get a new tv, the sales guy mentioned they were the third folks that week from our neighborhood replacing a downed set). Anyway, I was thinking about getting one of those residential surge protectors that you install at the panel. Any suggestions?
OK, could someone give details as to why so many negative remarks regarding MOV's? Why are they so detrimental?
I agree with three posts here. 1. Use the Environmental Potentials at the breaker panel. 2. Have another surge protection devise close to the equipment. 3. Avoid MOVs.MOVs work better as the voltage increases. So for lower voltage surges, some of the surge gets through. This happens unless you have a sophisticated, industrial devise with MOVs.One product I use close to my equipment is the Russ Andrews Mega Clamp. Russ Andrews Accessories Ltd. has similar products, at lower and higher prices.
......The first thing the power supply in every electroncs device you own (except a some turntables) is provide filtered DC power. The capacitor in the power supply should filter all RF noise and other spurious occasional power anomolies. ....
Chances are if the equipment doesn't do that itself, no external filter will either.....
http://www.dms-audio.com/megaclamp-cloneYou can see there really isn't much to these and they do use MOVs, in this case 10 of them, plus one small capacitor and a resistor. I don't know what manufacturers charge for them but if it's more than a few dollars you're getting ripped off.
If wishes were fishes....Unfortunately, the typical electrolytic capacitor in a power supply doesn't work at > MHz range given inherent ESL (equivalent series inductance) which limits its ability to shunt noise with increasing frequency. For whatever reasons (no doubt economic) the typical toroidal transformer used, without a primary/secondary grounded shield, lets is all sorts of noise through. and Felix is laughing too......
I'm sorry, but you are talking non-sense. RF filters of all sorts have been made for decades, intended for consumer, commercial, and military applications. Many CD players, DACs, and other audio components, have RF filters right in the chassis. The newest Mark Levinson Player is one example. Another is Northstar, made in Italy. The list is numerous, and spans Pro Audio, as well as consumer audio.
The first thing the power supply in every electroncs device you own (except a some turntables) is provide filtered DC power. The capacitor in the power supply should filter all RF noise and other spurious occasional power anomolies.
Whether it is true or not that a large electrolytic capacitor will filter RF noise in a power supply (assuming it's actually a problem, most of it is frankly a myth since series inductance in the transformer ahead of the rectifier has an impedance that increases proportionally with frequency and is practically an open circuit at RF frequencies) you can simply solder a low value capacitor across the electrolytic to act as an RF shunt. Say a .047 mfd cap should do the trick. Just be sure its voltage is as high or higher than the electolytic caps is. It should cost less than $1 and will be every bit as effective as the expensive manufactured product in this regard. And buyng expensive film caps for which great claims are made in signal circuits will not produce any better results either. I design and build power distribution networks for among other things the most advanced scientific laboratories and data centers and specify very expensive UPSs and other power protection devices. Those sold to audiophiles are by and large overpriced, oversold, worth far less than is claimed for them, and are one big ripoff. If you want a real power protection device that will give you the best results, you have to buy a double static conversion UPS from a reputable company like Eaton or Liebert. They will cost over $500, even a thousand dollars or more. The cheaper line interactive type used for PCs work fine for that application but may not be suitable for audio equipment due to high THD, up to 40%. PCs don't care about that. To find out whether or not the product you are considering is a ripoff, you need to learn what the alternative technologies are, what's in the product you are considering, and what its performance specifications are. Do not be intimidated or impressed with generalizations designed to frighten or overwhelm you. Those are the sales tactics of people who have little to offer of real value but have a very high sticker price. Most are little more than a box with a bunch of receptacles, a few MOVs, a few small capacitors, inductors, and a light show, maybe a switch or two. They aren't worth it. If you are handy with a soldering iron you can build one cheaply enough yourself for very little money. A very expensive one that offers more than the usual run of the mill types but less than a UPS contains a large heavy computer grade isolation transformer. Sometimes those are included with very expensive UPSs.