I have always found high-end power cables intriguing. It is certainly beyond the realm of my intuition that such a passive component, outside of the signal path, should have any significant sonic consequence, yet some cords are capable of effecting startling improvements. Indeed, the NBS Signature II and Audiodyne Power Tap AC power cords provide ample evidence, to varying degrees, that one's intuition is best checked at the door to the house of the high-end.

N(o) BS
Although NBS has been in the business of designing and manufacturing high-end audio cables for over ten years, they have kept a relatively low profile, almost shunning the high-end audio press and advertising only sporadically. Whether by design or a stroke of luck, NBS's low-key marketing strategy has created something of a mystique surrounding its products and their enigmatic designer, Walter Fields, serving to fuel further interest in the company's expanding product line (which now includes cables at down-to-earth prices as well as those that would give Sir Edmund Hillary a nose bleed.)

The design of the Signature II is not something that Walter Fields or NBS seem to want to talk about. To their credit, they don't spout the usual hyperbole and pseudo-scientific B.S. so common in this segment of the industry, but offer little of consequence when it comes to describing the particular design points that separate their cables from the dozens of others available currently. The scant documentation provided by NBS states simply that the cable utilizes a "unique wire weave pattern" and constitutes a "Passive Frequency Induction Network" which can only be achieved through "hand-made construction using the purest available copper, gold, rhodium, chromium and silver combined with the most effective dielectric of all: air". Since nothing even resembling a white paper on the design of the Signature II was provided, I had to content myself with simply listening to the cable in order to unravel its secrets. I wasn't disappointed.

While $650.00 for a four foot AC cable may seem absurd (a six foot version of the Signature II is available for the same price - small mercies), the positive impact the Signature II had on the sound of music played back on my reference system was undeniable. The sonic effects I normally associate with a good power line conditioner, namely a considerable reduction in background noise and grain through the midrange and treble, were abundantly evident with a Signature II feeding the power to each of the VPI Synchronous Drive System, Audible Illusions Modulus 3a preamplifier and SimAudio Celeste Moon W-5 power amplifier.

Mere moments into Milt Jackson's Live at the Village Gate (OJC 309) and it was clear that the Signature II was having a profoundly positive impact. Hampton's vibes, which, on this budget LP, can sound clangy and somewhat overbearing in their forwardness, rang out bell-like, with a sense of lightness and clarity that failed to materialize fully with the stock power cords in place. The magic continued on Hittin' It from Chick Corea's Trio Music in Europe (ECM 1310), where the sound of Roy Haynes' wide array of drums, cymbals, and other percussive instruments, was considerably more present and tangible than heard previously. When listening to this recording (which does, I'm afraid, give away its digital origins), I am always delighted by the way that the ECM engineers managed to capture the essence of the hall as excited by Haynes' snare drum flams. While this hall effect was readily heard with the inexpensive stock power cords, the Signature II was more adept at fully fleshing out the ambient trails as they faded into the hushed silence of an awe-struck European audience. A superior audio accessory serving a superb musical performance.

The twentieth century's most prodigious symphonic works also benefited from the Signature II's presence. Where the stock power cords subjectively choked off the system's ability to palpably portray sudden swells in orchestral volume, the Signature II seemed able to widen the pipe through which musical information flowed, often to an astonishing degree.

It is often said that the true measure of a component is the magnitude of the musical void it leaves when removed from the system. By this metric, the Signature II is an indisputable success. With little overstatement, my system sounded broken when I removed the trio of power cords at the conclusion of the review period (it's remarkable how the mind adjusts to sonic changes, even when they're for the worse. Within days, my system, sans Signature IIs, satisfied again.)

Attempting to judge the value of a $650 power cord is a difficult task (the $3000 NBS Statement power cord is another story altogether). Down here on the ground, a good integrated amplifier, high-quality entry-level source component, or small, but fine-sounding, pair of loudspeakers could be had for not much (if any) more. For those less fiscally constrained, however, the Signature II is a highly accomplished audio accessory - one of the finest I've run across, in fact - and is certainly worthy of serious consideration by those who can afford its copious charms.

Power On Tap
I must preface my remarks on the PowerTap AC cord with an apology to the good folks at Audiodyne. Due to a series of unfortunate scheduling difficulties, our review of the PowerTap was severely delayed - by a great many months, in fact. A delay of this magnitude rarely, if ever, occurs at Audiophilia but, regrettably, it did in the case of our PowerTap review.

Groveling aside, the PowerTap AC power cord is one member of a sizable lineup of cable products from Audiodyne, a relatively low profile, direct-sales audio cable company from Las Vegas, Nevada. When I first came upon Audiodyne, their flagship product was an interesting looking omnidirectional loudspeaker, a la the mbl Radialstrahler. Cable products appeared secondary, perhaps there simply to subsidize the omni's continued design and development. If the current version of Audiodyne's web site is any indication, it appears that the loudspeaker is no more, and Audiodyne has joined the ranks of the Great American Cable Companies, whose membership continues to expand at cosmological rates (which might explain their fascination with the Hubbell plug.)

The PowerTap looks much like you'd expect of a high-end power cable: it's thick, but not terribly unwieldy (by contrast, routing the NBS Signature II around the back of an equipment rack is like wrestling a ninety pound alligator), covered in a braided black sheath (of unspecified material), and terminated with a laboratory grade nylon plug with nickel-plated blades. Conductors are 10 gauge, silver-plated, six nines copper. Nothing particularly unusual or groundbreaking here. In fact, of all the high-end power cords from all of the high-end cable makers, the PowerTap AC cord is certainly one of them.

The sonic advantage of the PowerTap cable over garden variety OEM cords was audible, if notably more subtle than with the NBS Signature. Dynamics were ever-so-slightly more convincing, bass extension and definition were a hair better, and transients had less zip and bite. There were no apparent sonic degradations using the PowerTap, but what improvements there were could best be described as undramatic.

If you're looking for a power cord that will effect a considerable improvement in the sound of your system, then look elsewhere - the NBS Signature II, for example, or, perhaps, one of the similarly-priced cords from Harmonic Technology, which have recently arrived for review and sound very promising. If, on the other hand, you're looking to improve upon the OEM cords that were included with your gear and want to do so on a reasonable budget, then the Audiodyne PowerTap AC cord might just fit the bill. Take advantage of Audiodyne's generous thirty day money back guarantee and audition the cables in your system, risk-free. Then decide whether or not they're worth the investment.