Mains Power

There has been a lot of talk lately about mains power and the increased availability of power cords, power filters, noise reduction devices and conditioners. Stores have a bewildering array of devices at all levels and prices and all promise improved performance and / or safety. So what do these things do and what you really need?

Surge Protectors: These devices are generally relatively inexpensive and are supposed to protect your video and hifi equipment from large surges of power down the mains. Lightning, industrial equipment, power transmission equipment failure and even possums on power lines can cause surges. These devices often use parts to dump the excess power to protect the gear. They can work quite well, many manufacturers offer insurance if they don’t work but make sure to read the fine print as often many conditions apply. They may not protect against everything, so in storm conditions it may be a good idea to unplug sensitive equipment. Surge protectors can also be fitted direct at the fuse box, protecting the entire house; however it again won’t necessarily protect against everything. Prices vary a lot, generally the more you pay, the greater the amount of protection.

Filters: Mains power 20 years ago was mostly clean, especially in suburban areas. Very few faxes, computers and data transmission over mains existed, but now there are so many devices plugged into the grid there is a lot more noise than there used to be. Some devices cause more noise than others, computers use switch mode power supplies which can be inherently noisy for example. The amount of noise also depends on the time of day; nighttime, when business has closed down and factories are quite, has the lowest levels. Some people have commented that at night their system sounds better. It could also be due to the slightly higher mains that some areas have for the same reasons. Without specialised test equipment it is hard to tell how much noise is in the power supply so your results with filters may vary depending where and when you use them. See if you can test them first if you think you have a problem. The higher-end the hifi equipment, the better the internal power supply filtering usually is. This will help a lot and certainly make the problem less of an issue.

Power Cords: One interesting aspect is the proliferation of new power cords. In some cases they certainly can make a difference. Most households wiring for power points are designed to handle fairly high current (>20A) while the power points are rated at 10A. Most equipment is well below this rating. However some of the power cords supplied with units are only of low capacity and maybe of poor construction, so a better cord can help deliver the power efficiently to the equipment. Some power cords are incredibly expensive and their performance is under much debate. If you think such a cable will make a difference, make sure you can return it if it doesn’t and don’t be swayed by emotions! Also be on the lookout for cables that have not been safety tested to Australian standards. Many are sold in this country without the safety testing which is required for all Australian detachable power cords and power boards. I personally once saw speaker cable being used for 240V mains; this is very dangerous as there was no way of knowing the insulation’s capacity for high voltages or the stability of the plastic!

Power Conditioners / UPS: Uninterruptible power suppliers are now becoming common for hifi gear. They used to be the domain of computer equipment in case of power failure to keep from losing work; now people have started to use them to protect hifi equipment from surges and noise. Specially made power conditioners such as from Pure-AV, Monster and DBA Electronics are usually high-end solutions and can provide all in one solutions. The ultimate ones actually re-generate the mains completely, so that the power to the equipment is completely isolated from the mains.

Plugs and Sockets: This is a similar area to that of power cords, some overseas stores will sell souped up versions with all sorts of exoteric materials. Some others will argue all that is needed is a clean connection and high current carrying ability. Also keep in mind that these overseas connections may be rated at 110V not 240V plus certainly most wouldn’t be approved for use in Australia and hence illegal. If your power points are very old they may be corroded inside or the contacts are loose. Get an electrician to have a look and even fit new ones. Some people have had electricians fit 15A power points and plugs to their equipment; this is regarded as much safer than doing it yourself with illegal parts plus utilise thicker wire to help avoid any possible issues.

This is really an interesting area of hifi, some products that are for protection have little argument against using them, however some people are at opposite ends when it comes to the more unusual or extreme products. Some say it is a waste of money; others are very impressed by the improvements obtained. Some say filtering and protection devices “choke” the sound, others think improvements can be had. So ultimately it is up to the individual, if you are looking at these types of products make sure you do your research and make sure the manufacturer or retailer is willing to let you try it out for yourself.

Written by Leon Gross, originally published in Audio & Video Lifestyle magazine.