Powerline Accessory Reviews

Editor: Just received the August issue of Stereophile and what do I read? A couple of crybabies taking one of your boys to task for a negative review. "Wah! I spent my money on this stuff, which means it has to be good. So you're wrong, Mr. Stereophile Editor Man. Wah!"

Typical spoiled yuppie losers.

Correct me if I'm wrong, but the license of critique extends to the negative as well as the positive. It doesn't have to be pretty. It doesn't have to be diplomatic. And, because you drape yourselves in the flag of subjective review über alles, it doesn't have to be empirically correct, either. That's your privilege.

Frankly, Stereophile would benefit from printing more negative reviews. Balanced journalism demands it. There's a lot of crappy gear out there and your mature subscribers would like to know about it, too. (Besides, you wouldn't want to be accused of pandering to the almighty advertising dollar like those mainstream mags, would you?)

Whiners, pay attention: Stereophile is a source of information. It is not the source, nor is it the last word. Take what you read with a grain of salt, and trust your ears.—"I.M. Outthere", St. Louis, MO, Webnanmar@aol.com

Theory agreeing with practice

Editor: Jonathan Scull's review of the Richard Gray's Power Company power-line conditioner (June 2000), in which he detected little or no sonic benefit, provides a rare instance of theory (in audio) agreeing with practice. I don't mean to take a swipe at Mr. Gray, but as there are so many similar devices competing for the audiophile's buck, I think that some further discussion of power-line theory is warranted.

Mr. Gray is quite correct in maintaining that series resistance is the cause of power-line problems. In fact, resistance is the only way that energy can be lost! This resistance can be apparent (eg, wire and contact resistance) or hidden (transformer coupling efficiency). It is important to note that this resistance, all the way to the power pole, adds up.

Ideal inductors and capacitors, having no internal resistance, cannot burn up energy, but instead store it as magnetism and electric charge, respectively. Since energy is stored differently in each component, the way in which energy is accumulated and the way it is released differ. They are, in fact, complementary devices.

The purpose of a power supply is to provide constant electric force—voltage—regardless of the fluctuations in current flowing in the load. One source of current for the load is the inductance of the power transformer. Paul McGowan of PS Audio related, in his May 2000 Stereophile interview, that a small transformer does not sound as good as a large one with proportionally greater inductance. The difference probably arises because of the greater magnetic field, as well as the somewhat lower winding resistance.

Short of replacing transformers, can we improve the situation? Sure. Just add inductance in series with the transformer. Whenever the line voltage decreases, current in the transformer and in the inductor also drops. The inductor fights the change in current by collapsing some of its magnetic field. This momentarily boosts the voltage provided by the power line to a value just high enough to restore the old current flow.

Mr. Gray does not do that, and for a very practical reason. In addition to the extra inductance, a coil also inserts resistance. It takes a monster of a coil to provide both high inductance and low resistance. Instead, Mr. Gray inserts his inductance in parallel with the blades of the power plug. The problem with this solution is that it simply doesn't work! The coil does not see any of the current drawn by the transformer because it has its own independent connection to the power line. Furthermore, the lower the resistance, the slower an inductor discharges. Since in this position, the inductor looks directly into the power station, it will discharge slowly, indeed!

So are we out of luck? Theoretically, no. The power utility puts a particular type of capacitor across the power line in order to reduce noise and distortion, improve regulation, and compensate for excessive line inductance. Such a capacitor senses a drop of voltage and instantly provides current to compensate. This is exactly backward from the action of the inductor, as is the proper hookup.

Unfortunately, applying capacitance to an AC power line is a very tricky thing that can easily cause death and destruction of property. I do not know of any manufacturer who would dare to put such a device on the market.

That leaves us with a few safe options. First, you can simply buy a well-designed power filter; second, as a result of some experiments done several years ago, I can personally recommend power regeneration, especially for the more sensitive, less power-hungry devices; third, experiment with plugging these components into their own power strips and placing additional loads (lamps, etc.) across the same circuit. For some reason, my turntable always sounded more enticing with the CD player idling.

Finally, don't forget to orient your power plugs for the best sound. It really does work. Best of luck!—Bob McIntyre, Toledo, OH, sideshowbobmac@thesimpsons.com