Analog Corner

Are you old enough to remember when the wires connecting speakers to even the most expensive and sophisticated electronics were 16-gauge, multistrand lamp cord, and the terminals on speakers and amplifiers were just little screws? Sometimes those screws wouldn't even secure all of the wires' strands, but as long as loose strands from one screw didn't touch loose strands from the other, it was good enough . . . and back against the wall went your bookshelf speakers.

And do you remember plugging the plugs of lamp-cord-like AC leads into any old wall sockets, themselves connected to any old household circuits?

I remember all of that. No doubt the first high-quality stereo system I ever heard, back in the mid-1960s, was hooked up that way—and it sounded amazing. I'll never forget that system: all McIntosh electronics, Benjamin Miracord turntable . . . and lamp cord. I didn't know it was lamp cord, I didn't see it, but I'm 100% certain it was there. At the time, that's all there was.

I wonder how much fun might it be to go back half a century with the latest in interconnects, speaker cables, power cords, and power conditioners, and hear how much better such a system might have sounded. "No better" would surely be the answer from some folks whose opinions regularly hit my inbox. "Enjoy your lamp cord," I respond, and move on.

In the 1960s, today's electrical problems didn't exist: a lot more bad stuff of the digital kind plugged in at home and all over the neighborhood, placing far greater demands on our now-ancient grids. That technology was essentially designed for lighting and motors, and is now stretched to or beyond capacity; at the same time, contemporary audio gear is capable of delivering far wider dynamic range—and is in ever-greater need of clean power. Large power amplifiers pull a great deal of current, front-end gear not so much, but both need some way to filter out the noise caused by radio-frequency interference. RFI noise is the enemy of dynamic range and transparency, among other qualities we demand from our systems.

This piece isn't the place for a critical overview of the various theories about how to filter noise from AC power lines, and I'm definitely not qualified to write one. Still, I've been fortunate to have some of these theories explained to me, in ways that even I can understand, by various experts in the field. Though these experts approach the problem in different ways, their goal is the same: reduce noise in the power line without limiting the amount of current delivered.

The non-experts put a simple low-pass resistor-capacitor (RC) filter, capacitor-input (Pi) filter, or isolation transformer in a box and call it a day. Or they put in even bigger capacitors than the other guy's and call it a week. Throw in a noisy sinewave, out comes a clean one, and voilà . . .

But filters are vulnerable to unwanted oscillation or ringing, which can produce a transient edge that, in some circumstances, listeners mistake for increased detail. Additionally, as measurements that I've seen appear to demonstrate, simple low-pass power filters can impede current delivery by producing highly reactive loads, as seen by the power supplies of the components you've connected them to—and those filters can operate in ways analogous to how a speaker's varying impedance sometimes modulates a power amplifier's frequency response.

The point is, there is no simple way to remove noise from power lines without also affecting current flow, line impedance, and voltage flow—all of which are interrelated. But good designers know what the problems are, and work to reduce them by making wise choices. In the end, though, any power-filter design must be evaluated on the basis of not only how it measures, but of how it does or doesn't affect the quality of the sound. You have to listen to it.

AudioQuest Enters the Power-Conditioner Market
In the past few years, cable company AudioQuest has branched out into other areas, including the manufacture of highly regarded DACs and headphones. (A cynic might say that the company sees the wireless handwriting on the wall.) But before he entered these crowded and well-established markets, AudioQuest founder and CEO Bill Low hired highly talented people, then gave them the time and resources to design products that immediately distinguished themselves. I've known Low since 1982, before I became an audio writer, and it's obvious to me that he's doing it as much for the pleasure of seeing what his hires can come up with as for the money-making potential.

For the project that eventually resulted in the Niagara 7000 Low-Z Power Noise-Dissipation System, Low hired Garth Powell, gave him the title Director of Power Products, Engineering, and unleashed the former Furman Sound engineer to do his thing. It seems Powell had ideas that extended beyond the staid engineering practices of his former employer.

For instance, at the 2015 Consumer Electronics Show, the loquacious Powell demonstrated to a group of mostly veteran audio critics that ground wires are directional. He played a recording of a trumpet piece, then reversed the green ground wire and played the file again. We didn't use an A/B/X box to go backandforthandbackandforthandbackandforth in order to remove "confusion": The difference was easily audible to everyone. (What confused me was Powell's explanation of why there was a difference.)

A few months ago, Powell, along with AudioQuest's Joe Harley and Stephen Mejias, paid me a visit. We spent some time listening to music through my system, which included my longtime reference power conditioners: two sets of Shunyata Research's Hydra Triton v2 ($6995) and Hydra Typhon ($5995) power distributors, one for the preamp and source components, one for the power amps across the room. I've visited Shunyata's impressive facility in Poulsbo, Washington, and have the greatest respect for their products, and for designer Caelin Gabriel's work and expertise. More important, their power conditioners and cords work as promised, which is why, for years now, various iterations of their conditioners have been my references.

After a few happy hours of playing tunes, during which no one faulted the sound, we swapped out the two sets of Shunyata Hydras for a single Niagara 7000, using long runs of AudioQuest power cord from the amps to the Niagara, which I set up across the room on my Harmonic Resolution Systems equipment rack.

Snazzy Looks
With its beveled and black-chrome-plated faceplate and sculpted waterfall graphic, AudioQuest's Niagara 7000 Low-Z Power Noise-Dissipation System is an uncommonly attractive power conditioner. In an advertising one-sheet long on marketing lingo and short on technical detail, AQ bills it as a "complete rethinking" that "revolutionizes the art and science of AC power," and provides a cogent rationale for a conditioner: "it can be proven that up to a third of a high-resolution (low-level) audio signal can be lost, masked, or highly distorted by the vast levels of noise riding along the AC power lines that feed our components. This noise couples with the signal circuitry as current noise and through AC ground, permanently distorting and/or masking the source signal."

AQ acknowledges that "many approaches can yield meaningful results," then lists some of the common power-conditioner shortfalls I've already outlined: ringing, current compression, and nonlinear distortions. What AQ describes as the solution is conceptually very similar to what Shunyata espouses: "unimpeded current delivery across a wide range of frequencies." However, AQ claims a more comprehensive solution that includes "optimized radio-frequency lead directionality, run-in capacitor forming technologies developed by Jet Propulsion Laboratories and NASA, and AC inlet and outlet contacts with heavy silver plating over extreme-purity copper assuring the tightest grip possible." In addition, says AQ, "The Niagara 7000 uses our patented AC Ground Noise-Dissipation System, the world's first Dielectric-Biased AC Isolation Transformers, and the widest bandwidth-linearized noise-dissipation circuit in the industry"—the last something I was unable to measure and confirm. "Our unique passive/active Transient Power Correction Circuit features an instantaneous current reservoir of over 90 amps peak. . . . Most AC power products featuring 'high-current outlets' merely minimize current compression; the Niagara 7000 corrects it." (AQ's emphasis.)

On the Niagara 7000's rear panel are 12 AC outlets, four with "High-Current/Transient Power Correction" and eight claimed to offer "Ultra-Linear/Dielectric-Biased Symmetrical Power." The Niagara's AC jacks are the most difficult to use I've ever encountered, but also have the most effective grip. According to the informative and excellently written owner's manual, the grips' purposes are to lower impedance, improve transient-current delivery, and reduce noise, "to name a few." The four High Current outlets are hard-grounded. The eight others are divided into two groups of four, each group 100% isolated from the other, and both 100% isolated from the High Current outlets.

AQ's other bullet points:

• Direction-Controlled Ultra-Low-Resistance Solid Core Wiring
• Ultra-Linear AudioQuest AC RF Filtering Capacitors
• Dielectric-Biased AC Isolation Transformers
• Transient Power Correction
• Patented Ground Noise-Dissipation System: 6 banks of direction-controlled ground noise dissipation
• Ultra-Linear Noise-Dissipation Technology: More than 21 octaves of AC differential and common-mode filtering with linear response, optimized for varying line and load impedance
• Non-Sacrificial Surge Protection
• Zero Ground-Contamination Technology
• Over-Voltage Shutdown with Automatic Reset

Whew!