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Stuart, Whether filters (or power conditioners) will work for you depends on the characteristics of the electrical noise on the line (spikes, dips, emi/rfi, motor whines, light dimmers, clicks..), and the filter's or power conditioner's capabilities (what frequencies/types of noise can it remove, and how much reduction). It is best to start with treating the noise at the source, if possible. Some interesting reading about this approach and a noise sniffer at: http://www.soundstage.com/revequip/db04.htm Regarding refrigerators, I found this: The classic solution is to put a capacitor across the contacts of the thermostat of the fridg to prevent arcing. Something like a 47mfd 300V ceramic for 120V. Another option would be to wind the power cord of the fridg through and around a ferrite core. Or do both. For more information check out the ARRL Handbook. -------------- Regarding ferrite cores: Ferrite RFI blockers These are placed on power cords in the system and also at strategic places throughout the house. Most important places - TV sets, computers, burglar alarm system, refrigerator. Recommended: Large toroidal cores made by Amidon Associates, Santa Ana, CA. Types F-240-43 (ferrite) and T-300-2 (iron powder material). These are available in electronic parts stores. An alternate mail order and international source is Surplus Sales of Nebraska. E-mail: grinnell@surplussales.com or URL: www.surplussales.com. Catalog part numbers: iron cores (ICH) MM-T157-2 (page 57); ferrite cores (ICH) 57-1465 (page 55). The toroidal cores are partially effective just leaning on a power cord and can be evaluated for system improvement this way. This tweak must be carefully adjusted and evaluated by ear. Just one core too many can tip the balance from smoother with reduced “grundge” to hard and edgy. http://www.magnan.com/column.shtml#ferriteblockers ------------- Another product for use at noise source: http://www.smarthome.com/4845acf.html Also this tidbit: Although many low-cost power outlet strips sold at hardware and computer stores claim to include RFI filtering, in truth none of them contain filters that are really effective. You need to purchase a genuine industrial-grade RFI filter from an electronics parts supplier. Both Mouser (mentioned above) and DigiKey (800-344-4539; on the Internet http://www.digikey.com) sell the kind of filter I'm talking about here. I have used filters made by Corcom (sold by DigiKey) and Cornell-Dubilier with great success, and they range in price from $25 to $65 each, depending on their capacity in Amperes. Don't waste your time with cheaper units; buy only Series R two-stage L-C (inductor-capacitor) filters. http://www.ethanwiner.com/dimmers.html ---------- Hope this helps a bit. bret --- Stuart Wyatt <stuart@solostring.com> wrote: > Hi all, > > I'm trying to find a unit that will clean up any mains > interference/noise on the circuit at home (I live in a small > apartment, > with lots of gadgets like neighbours fridges making strange random > noises). Has anyone had any experience with units like this? Do they > work? > > Just a random question :) > __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com