Audio Accessory Review!CPT Equi=Core 300Balanced AC Power Source

If you have AC line noise, balanced power can help  ©EAN

Brevis...

Likes: can clean noisy AC

Dislikes: No AC outlets (on 300)

Wow factor: based on science
More info: Equi-Core Model 300

by John Gatski

  Balanced power isolation transformers have been around for more than 50 years, and in recent years, various companies have catered to the high-end audio community in search of a way to lower extraneous audible AC line noise. It is not a 100 percent sure-fire cure, but plugging into balanced power supplies can certainly provide stability and a central grounding source for your precious gear,

Features

  The Equi=Core 300 by Core Power Technologies of Colorado is their mid-level unit at $799 MSRP with 300-watt output capacity. The company also sells a 50-watt version for $499 MSRP and 150-watt version at $599 MSRP. These three models do not come with built-in output receptacles; you have to use an outboard power strip with a modular IEC power input. Newly added models 1200 at $1399 MSRP and 1800 at $1,799 MSRP are now shipping  as well, and they do come with eight built-in NEMA Hubble or Schuko receptacles for those who run big power amps and multiple components.

  The onboard standard power cable length of the 3 smaller models is 2.5 feet with the option to increase the length to 5.5 feet or 8.5 feet for an extra charge. The larger units come equipped with a standard 6.5’ power cable. We ordered the high-quality, but budget-priced, Wireworld Matrix2 strip to to use with the Equi=Core — about $120.

 The Equi=Core 300, however, impressed me with its relative transformer silence. I had to put my ear on the unit to hear the negligible hum of the transformer. No way you could hear it at the listening position — even with the volume muted.

  As an AC accessory box, the Equi=Core does not have any controls, meters, lights, etc. It is sturdily built, looks modern, and is not that big. It has a receptacle for the outboard strip on one side and its own heavy gauge AC power cable with quality three-prong, U.S. spec plug. It weighs about 15 pounds.

  Balanced power is essentially an isolation transformer with a secondary-side center tap to ground, providing two separate AC legs. The balanced circuit takes a 120V AC and divides the power into 60 volts on either side of ground, so the full 120 volts are provided via the unit. (In a typical unbalanced AC system, the main conductor has 120 volts to ground and the neutral has 0 volts to ground).

  Balanced power voltages flow 180 degrees out of phase to each other (with respect to ground). The out-of-phase design results in a noise-canceling effect that can audibly reduce power line noise via enhanced common-mode rejection. For this all to work, the important ground link is made via  the  output center tap of the balanced AC isolation transformer. This system ground is then linked to the true earth ground via the properly installed AC outlet, netting an effective ground for proper component operation and safety,

The $120 Wireworld Matrix2 is a good mate for E=C 300

  In my experience, balanced power can benefit an audio system if “dirty AC” is at play, and at the very least it provides an effective centralized ground for all your components. I reviewed the Alpha Core unit in the early 2001, and I found it did lower extraneous, audible line noise and some 60 cycle hum that was produced in one room in my house that had a number of noisy AC devices on the unbalanced circuit. The balanced power, therefore, can improve low-level sonic definition by lowering the background noise that gets transferred from AC line.

  However, on a noise-free, up-to-spec unbalanced AC circuit that is properly grounded with good receptacles, I believe there is little benefit, other than a central grounding system. These boxes do not magically transform your audio, but rather curb inherent noise on the AC line. It will not cure the self-induced noise of a tube amp or any other component that generates its own background hum and hiss.

Cure the noise

  So when I was sent this unit, my previous experience proved beneficial for the review of the Equi=Core. In my main audiophile room, I have a dedicated, unbalanced AC system that has its own fuse box and earth ground, with professional-grade, grounded outlets. I don’t have AC-infused noise infiltrating my audio system. Therefore, the balanced power is not necessary. Putting in the system did nothing as far as changes in audibility of noise, since there is no noise other than what the components generate at low levels.

 I found that, indeed, the Equi=Core significantly reduced the buzz and audible 60-cycle hum. The hum was knocked way back to the point you could not hear it through the speakers — unless you put your ears right next to the drivers. 

  However, a secondary room that I wanted to use for audio demos has AC fed from the houses’ primary fuse panel. There is a mixture of grounded and ungrounded outlets with refrigerator and cable box plugged into the circuit. Audio devices plugged into any one of three outlets in this particular room reveal persistent, audible hum and buzz. It is loud enough to hear through speakers with the volume all the way down on the stereo amp. Headphone amp listening reveals the noise to an even worse degree and is very distracting. My guitar amp really picks it up as well.   As with my experience doing the Alpha-Core review in 2001, this noisy AC portal was a perfect candidate for the Equi=Core’s balanced power unit.

  Setting up a Coda high current preamplifier, Pass Labs XA30.5 amplifier with Westlake LC8.1 speakers, and later a Bryston BHA-1 headphone amp, I found that, indeed, the Equi=Core significantly reduced the buzz and audible 60-cycle hum. The hum was knocked way back to the point you could not hear it through the speakers — unless you put your ears right next to the drivers. (With the volume turned down of course).

  There was still some buzz with the volume all the way down, but attenuated downward significantly from the non-balanced power plug-in test. The guitar amp cleaned up quite a bit in the hum department, though the self–induced hiss was still there. These boxes cannot cure the internal noise of the component, but having a balanced power AC system with a centralized, proper ground can lower ground loop noise, and extraneous AC line noise.

The $1,799 high-capacity Equi=Core 1800

  My gripe with big transformer power supplies (including balanced power units) is that the transformer lamination vibration noise often is louder than the AC noise you are trying to cure. Big ole transformers have a tendency to vibrate and make mechanical noise. (I have a 40 amp ham radio power supply that had to be put in an isolation box, just so I did not have to hear its ample vibration noise).

  The Equi=Core 300, however, impressed me with its relative transformer silence. I had to put my ear on the unit to hear the negligible hum of the transformer. No way you could hear it at the listening position — even with the volume muted.

  The only fly-in-the-ointment with this review was an issue with the built-in cord, the strain relief grommet pulled out of the unit under significant stress (like accidentally tripping on it) and you could see the individual wires contained in the cord. It did not affect the performance, but the company has been notified and is adding additional stress tests to its QC regimen to makes sure the grommet is strong enough to keep the inside, er, inside.

  I also believe the manufacturer should bundle the balanced power unit with an outlet strip. If I order one, I don’t want to have to chase down the separate outlet strip. The old Alpha Core’s was built in. In my opinion, with the separate strip designs, the manufacturer needs to figure out a combo price and include the strip in the price.

The verdict

 Having sampled balanced power for audio systems in the past, I think it can be a viable solution to reducing AC line noise that gets transmitted to your component, and it provides a solid central ground for your components. Does it magically transform your component’s audio output quality? No. But it can increase low-level resolution by reducing the competing AC noise that is audibly transmitted to your speakers.

  The Equi=Core 300 is reasonably priced, well-built and is not obtrusive with its compact size and modern look. If you have an AC noise problem and you want a centralized, high quality AC connection, the Equi=Core balanced AC power units are worth checking out. Because it did lower the noise in a problem AC circuit, I am giving it an Everything Audio Network Stellar Sound Award.

  John Gatski has been evaluating consumer, audiophile, home cinema and professional audio gear since 1988. In 1995, he created Pro Audio Review, and he has written for Audio, Laserviews, Enjoy The Music, The Audiophile Voice, High Performance Review, Radio World and TV Technology. Everything Audio Network is based in Kensington, Md. Articles on this site are the copyright of the ©Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited. John Gatski can be reached via everything.audio@verizon.net