Adding an AC power conditioner to your system can often be the single most cost-effective upgrade you can make. It’s surprising how much better music and home-theater systems can perform when fed clean power from an AC line conditioner.
Many audiophiles and home-theater enthusiasts plug their equipment straight into the AC wall outlets without a second thought. Conditioning the AC power line is reserved for the serious enthusiast, and is not a common practice among the general public.
That’s unfortunate because adding an AC power conditioner to your system can often be the single most cost-effective upgrade you can make. It’s surprising how much better music and home-theater systems can perform when fed clean power from an AC line conditioner.
Your system’s sound can be degraded by AC power in several ways. First, the AC line can be contaminated with high-frequency noise put on the line by factories and businesses. In essence, your home-theater system is connected to the factories’ noisy power grid through the AC power line. The AC transmission system also acts as an antenna, picking up AM radio broadcasts that get superimposed on the 60Hz AC. Even household appliances can add this high-frequency garbage, particularly products that use motors with brushes such as vacuum cleaners and power tools. The toroidal transformers used in many of today’s products tend to couple this noise from the AC line to the crucial audio circuits. If you’ve ever wondered why your system sounds better at night, it’s probably because the AC line is cleaner at night when factories are shut down.
But clean power from the wall doesn’t mean your AC line is free from noise. High-frequency junk also gets into your components from other components in your system. Say you have a DVD player and an AV receiver plugged into an AC wall outlet. Noise on the DVD player’s ground is put onto the AC line locally, where it enters the receiver through its power cord. Digital noise from the DVD player ends up inside your receiver, with the AC power line providing the pathway for this noise. The ground points in each piece of equipment within your system are connected together via the AC power line, transmitting noise between components. Even if you had your own electrical substation next to your home providing clean AC power, your system can still suffer from noise contamination.
The solution to both externally and internally generated noise is an AC power conditioner that filters noise from the incoming AC line, and isolates your components from each other. Virtually all line conditioners filter high-frequency noise from the AC line. Better line conditioners combine noise filtering with isolation filtering between components. These conditioners have banks of isolated AC outlets to keep analog and digital electronics separate. Such a conditioner may have some outlets marked “digital” and others marked “analog.”
Most modern power conditioners filter noise without putting any current-limiting electronics in the power-line signal path. These devices operate in parallel with the AC line, filtering noise without constricting the flow of current to your components. Although you plug your equipment into the conditioner, and the conditioner into the wall, the conditioner isn’t directly in the power path.
Whatever your budget, an AC power conditioner should be considered an essential component of your system. Most dealers will let you try one at home before you buy, or let your return it for a refund if you don’t notice an improvement in sound quality. If you do take home an AC power conditioner, however, I doubt that you’ll ever want to take it out of your system.
© 1998 Robert Harley
Adapted from an article published in Fi: The Magazine of Music