Power Conditioners: Justifiable Upgrade or The Emperor's New Clothes?

There are two schools of thought when it comes to power conditioners -- the "components" that are inserted between one's system and the AC wall outlet. One opinion has been candidly expressed by Howard Ferstler in the Staff Picks section of Issue 69, "that unless one resides in an area very different from what most Americans live in, a powerline conditioner will have no effect at all on the sound delivered by their hi-fi rig." The other view, I'll propose: sometimes power-line conditioners will make a difference, so read on if you are open-minded.

I have no doubt that a power conditioner would make not a bit of difference in, for instance, our esteemed editor's system. KWN lives in the country. There are hardly any sources of radio interference, nor drain on the power delivered to his home. In fact, he lives so far away from any other residences or businesses that the electric company installed a power transformer in his yard. This transformer supplies power to his house -- and his house only. Nearby radio stations? None. Nearby retail or industry? None. A difference in the sound of his system between daytime and nighttime? None. Does he complain of otherwise unexplainable background noise in his system? No. (Actually, it is the explainable background noise in my house that causes me to complain -- Tom has no children, but I have six living at home, plus a dog! -KWN)

Then there is my home. I live one mile outside the city limits of Washington, DC. The tower of a 50,000-watt FM station is less than a half mile from my house. The police station and its radio antenna are even closer. There are overhead wires supplying electricity, phone, cable TV, and who knows what else strung on telephone poles that wind through the neighborhood. Who knows how many homes get their electricity before it gets to mine. The metro train station is about eight blocks away. On my not-so-sensitive FM tuner I can tune in a station on virtually every frequency. Retail and industry are very close by. The sound of my system between the daylight hours and night can be radically different. Plus, there is sometimes a perplexingly slight 60-cycle hum, even when all grounding options are considered. A certain level of hum is something I've had to get used to. I guess you would call where I live the worst-case scenario.

This difference between day and night is so radical that my casual-listening wife, who only listens to the system from other rooms in the house, notices it. I can only do serious listening at night, and this and all the factors listed above prompted me to search for a solution. I thought a power-line conditioner might alleviate some of the problems. But I was skeptical.

Fueling my skepticism was the price of these power conditioners. I guess if they performed as advertised they might be worth it, but c'mon. OK, most of these devices were loaded with transformers and other parts that might justify at least some of their cost. But I didn't go right out and immediately try them when it was suggested to me. I thought that this might be another case of unscrupulous manufacturers just out for the money of gullible audio enthusiasts. And I would quickly abandon any thought of trying them in my system for more than a moment if I had to strain or otherwise convince myself that I was hearing a difference in the sound.

But that wasn't the case. There was an improvement in the sound of my system with every power conditioner I tried, but some more than others.

I'll start off with the one that made the biggest improvement in not only making the difference in sound between day and night much less, but improved the sound of my system so much it was as if I had inserted a much higher quality component into the chain. Whether it sounded like my front end, preamplifier, power amplifier, or speakers were improved is hard to say. But it was very dramatic, and impressive. I could easily write a full review on each of the following powerline conditioners, but I'm just going to give my relatively brief thoughts on the few I tried.

The best was MIT's Z-Center ($1,495 from Musical Interface Technologies, 13620 Lincoln Way, Suite 320, Auburn, CA 95603, 530/888-0394). The Z-Center has 10 power outlets: two unswitched outlets for power amplifiers, and the rest are switched outlets for the source components, two of which are isolated from the rest with their own fuse. The Z-Center provides ground-loop isolation, and in MIT's words: cleans up and transmits the fundamental power line frequency (50 of 60 Hz) while it absorbs other noise frequencies from the AC power line. The Z-Center uses dual filtered isolation transformers to isolate digital or analog source components from amplifiers and other noise producing components. The Z-Center is part of a line of power conditioning components offered by MIT, the Z-Center supplies over 1900 Watts to connect components. For larger systems such as more complex home theater set-ups or other systems that use multiple amplifiers, units such as their Z-Iso-Duo, that simply provide the isolation that is part of the Z-Center. Of course, like all the other power conditioners I tried, the Z-Center also acts as a surge protector.

In my system, there was no doubt that the MIT Z-Center worked as advertised. With it in the system there was much less of a difference between the sound of the system during the day or night. This difference was by no means totally erased, but it was so much better during the daytime than it was before that I thought nothing of performing critical listening during the day. There was also huge improvements in the system's overall sound, which included, but was not limited to, an erasure of all the background garbage.

With the Z-Center installed, the total absence of any extraneous noise was the first thing I noticed. Usually, especially with my preamplifier selector turned to phono, there is a certain level of background noise that I got used to over the years. I don't mean a loud 60-Hz hum that would occasionally occur because of a grounding problem, but just a low-level buzz that was "the nature of the beast," if you will. Now, there is dead silence no matter what the source. Even with my ear an inch from the front of the tweeter, silence. This made a big difference in the sound of the system.

The overall sound of the system was improved, which included an increase in transparency in the mids. Plus, the bass seemed to go deeper and was definitely tighter. The mids were made more clear and transparent. It was noticeable on every instrument on every CD and LP I played, and the treble was rendered more sparkling and realistic. There was no turning back now. I could never use my system without it. Next I tried the popular Tice Power Block III Signature ($1,595, from Tice Audio, 1530 Cypress Dr. Suite C, Jupiter, FL 33469, 561/575-7577). It is more heavy-duty than the MIT, with up to a 3700-watt capacity. It has two separate circuits for power amplifiers, and three for source components with 16 outlets. This unit weighs a substantial 50 pounds, and has two attached power cords that are supposed to be plugged into two separate circuits for maximum effect. Plus, it has a cool-looking meter on the front of its black cabinet.

The improvement in sound to my system with the Tice was also significant, but slightly less than the MIT. I'm not sure if that's the Tice's fault, though. Properly used, the Tice should be plugged into two separate power lines. I only have one located near my stereo, and I wasn't about to have another dedicated line wired to audition the duality of the Tice. Suffice to say, the Tice also performed as advertised. I just think the MIT is more suited to my system. As I implied in the beginning of this column, power conditioners are definitely a "try before you buy" component. The Tice may very well work as well, or better than the MIT in a different system, in a different home, in a different part of the country or world. However, the Tice is much better suited for larger systems. With the MIT you will have to add additional units to match the power capacity of the Tice.

I also tried a couple of less expensive power conditioners, the first of which was the Blue Circle BC85.1 ($895, from Blue Circle, 304 Justice Rd., Peoria, IL 39583, 343/ 948-4938). This more modest unit, is the top-of-the-line from Blue Circle's Power Line Pillow line. They say that their power line conditioner is designed to act as a buffer, ensuring one's components receive the cleanest possible AC signal. This allows audio component to properly reproduce recorded signals without interference caused by anomalies picked up along the AC route. The BC85.1 features an AC power cord that has four low impedance wires wound specifically to minimize RFI (Radio Frequency Interference) and EMI (Electro-Magnetic Interference).

Using the BC85.1, the difference between day and night is lessened, maybe not as much as the above two much more expensive models, but still not as much as it sounds when having no power conditioner at all (imagine taking part in an A/B/X test to determine whether there is a difference in sound between day and night? "OK, here is the sound during the day, and here it is at night," and twelve hours later being asked, "... when am I playing it now?").

This is where I start to sound strange (even for me), when I speak of the "sound" of the power conditioners as if they are a stereo component. The Blue Circle seemed to impart a bit of its own sound into the system, a slightly "burnished" tone. This wasn't a bad thing, really. The sound of the system was still better with it than without, it just had this slightly mellowing effect on the signal. And if I never heard the sound of the system without trying the more expensive models I certainly would be happy using this model. The difference in made to my system was still pretty dramatic, yet the difference between it and the MIT or Tice was not huge. Even though the difference in the sound of the system between day and night was a bit more noticeable, it still rendered the system's background silent, and made an overall improvement to the system's sound.

Plus, the BC85.1 looks groovy. It has a neon-like blue circle lit up brightly in the center of its aluminum face plate when powered that gives it a sort of futuristic appearance. At night, when the lights were turned off it filled the room with a mellow blue glow. Aaaah.

Finally, I tried the Chang Lightspeed CLS 9600 ISO ($820, from Lightspeed Audio, P.O Box 8287, Sylvania, OH 43560, 419/ 885-7266). This small six-outlet unit weighs only 9 pounds, most likely because it has no transformers. The 9600 is so lightweight that Chang supplies two inch long spikes with the unit. These spikes are supposed to be inserted into ones carpet to keep the unit stable because of the tension of the power cords when plugged into the unit. In its owner's manual, Chang also suggests adding weight on top of the unit to improve its stability.

They claim that because they use no transformers or coils in their power-line filtration scheme, there is no transient delay, no current limiting, no sonic coloration, and no loss of high frequencies. Instead, Chang passes the A/C through what they term "a unique multisegmented `lossy transmission' mechanism composed of select magnetic materials. This mechanism maintains proper impedances while severely reducing the effects of RFI/EMI." After a 72-hour break-in period, which they recommend, I attempted to determine whether there was any unique sound added or subtracted to my system that would set it apart from the other power-line conditioners I had tried.

I noticed that no, there weren't any additive colorations or lack of high frequencies that Chang claimed, nor was there any loss in transient response. But I really didn't expect any. I certainly didn't hear any loss in frequency response in the MIT or Tice units. I guess they just go about the task of filtering the power a different way.

Like the other conditioners, there was an improvement in the overall sound of the system as soon as it was inserted between the equipment and the wall socket. There was also a decrease in difference in the system between day and night. Although the improvement in sound was not as dramatic as the higher priced MIT and Tice units, it was still noticeable. I liked this power conditioner slightly more than the Blue Circle, but it was a close call.

So there you have it, my first experience with power-line conditioners. I still think they're awfully expensive for what you get, but now that I've heard what they can do for my system, I'll never play music without one, that is, as long as I live in my home in this electrically polluted area.

Back in Issue 51, KWN asked why the power supply of an amplifier couldn't do the same thing as what these power conditioners purportedly do. I wondered myself. And I think that may explain the differences or lack thereof some people hear between otherwise similar power amplifiers -- that the construction of their power supplies may indeed affect their sound. A case in point is in my review of Parasound's $895 1500 amplifier in Issue 70. IA/B'ed it with the $3,000 Krell KAV-250a amp. The Krell sounded much better than the Parasound.

I wish I had a power conditioner on hand when I wrote the Parasound review. I plugged both units directly into the wall outlet and compared them as before, and as during the Parasound's review period the Krell sounded much better. I then compared them when plugged into the MIT Z-Center power-line conditioner. The "sounds" of the amps were brought much closer to each other. I still preferred the Krell, but the difference in sound was not nearly as dramatic. Perhaps the benefits of the Krell's superior power supply was responsible for the difference when the units were plugged directly into the wall. But I also noticed that the sound of the Krell may have sounded slightly better when not plugged into the MIT, a bit more dynamic. After much experimentation, I preferred the more robust sound of the Krell used with the MIT. However, this exercise may have proved KWN's theory, at least a little. What I still don't get is how the power conditioner can be such an equalizer, making the Parasound sound so much more like the Krell, before the A/C gets to the power supply.

I ended up purchasing the MIT Z-Center, and I am hoping that one day I will not need it. Although I like living as close as I do to the city, I don't like what it does to the quality of my house current. But maybe someday those problems will be addressed by the electric company. Until then ...