I am definitely not the ideal candidate to review a piece of wire, be it cable or AC cord. Or perhaps in a certain sense I am: You'd be hard pressed to find an audiophile more skeptical of manufacturer claims, golden eared perceptions, or the crypto- (not to say pseudo-) science that has peppered the literature on interconnects and power cords for the last couple of decades or so. Once upon a time, wire was just wire, it was scarcely given a thought. And if it was, the only parameters that were of any concern were LRC: inductance, resistance, capacitance.

When I agreed to audition the LessLoss Dynamic Filtering  AC Power Cord , I admit I did not expect to be writing a review. I anticipated hooking them up, hearing no difference, and sending them back with a courteous thank you note. I'd had some truck with audio cables before (though with AC power cords only once, briefly). Years ago I traded a drawing to George Cardas for a pair of interconnects and a digital cable. I ultimately purchased interconnects and speaker cable from Nordost on the theory that LRC are all that really matters. I was once given an audition of PranaWire, interconnects and power cords, by the designer/manufacturer. I do not say these cables produced no audible difference, but a great deal of close attention on my part was required, and perceived differences were slight and invariably not quite a matter of certainty. Nowadays, of course, cables are part of the standard arsenal of audio equipment, reviewed constantly using the usual superlatives. Could thousands of audiophiles be deluded? Well, I suppose it's possible. Certainly there is ample precedent for great masses of people being deluded about one thing or another. (In this regard it is telling that many audiophiles find double-blind testing meaningless and inappropriate.) I fear that cables, for me in any event, remain a vexed subject. And what sense would there be in spending thousands of dollars for wire, no matter how beautifully made or well reviewed, if it makes no audible difference? To me.

Proprietary interconnect cables made some sense in theory at least; after all, they were carrying minute, delicate signals, and inductance, capacitance, resistance, propagation speed, dielectric, metallurgy, shielding, outer cover etc., were potentially significant considerations. Whereas  AC power cord s had simply to handle a fixed voltage (more or less) at a fixed frequency, and to supply current as it was instantaneously required. Hadn't they? I never saw much sense in expensive two-meter lengths of proprietary AC cordage, as if this could somehow compensate for the hundreds, even thousands of miles of aluminum and copper - a gigantic RF antenna system - bringing power to our doorstep. Filtering and regenerating devices, perhaps.  AC power cords, no.

But when I installed a pair of LessLoss Dynamic Filtering AC Power Cords (DFPCs) to my monoblock Bel Canto REF1000s, I immediately heard a stunning difference. What I had considered impossible suddenly was not only possible, but perfectly obvious. If I'd installed a new multi-thousand dollar DAC or amplifier and heard this level of improvement, I'd consider it well worth the money. What I mean is, there were major improvements, in clarity and detail and dynamic range, in, above all, that elusive quality called presence. A couple of weeks later I installed a third LessLoss cord, this one to my Bel Canto DAC3. Immediately I noticed an unambiguous improvement, not to the degree wrought by installing the DFPCs to the monoblocks, but still unmistakable: almost as if cotton balls had been removed from my ears. I do not exaggerate. A better pair of ears than mine were present for this test, and her comment was that going back to the OEM cord was like hearing the piano under water.

These three lengths of wire have improved the sound of this stereo to a remarkable degree.

But AC power cords? Well, I am prepared to believe my own ears. Particularly if squinting of the eyes and straining of the auditory faculties are not called for to ferret out a perceptible difference in sound. Now, as a long time 'non-believer' I have no experience or knowledge of how other  AC power cord configurations might effect the sound (or not), but there is quite definitely something going on in these AC power cords, and I strongly suspect it is the (proprietary) filtering ability of the wire that works much of the magic. (LessLoss is not widely reviewed yet, but those reviews I've read, by audiophiles who have experienced numerous  AC power cord s over the years, consistently aver the LessLoss DFPC is better than anything even remotely in its price range.)

The idea an AC power cord could make a difference to the sound reminded me of something Ivor Tiefenbraun never tired of saying: that the most critical component in a sound system was the source (he was referring to the Linn turntable, of course). Precisely: in the same sense, the quality of the AC power will color everything down stream to some degree, preamps, amps, digital converters, everything.

When my house was built, electrical codes were different. So I am grateful to have even a single outlet in the living/music room with a real ground. Unfortunately, it was necessary to place my equipment rack at the other end of the room. Plugged into the grounded outlet is a surge protector (ZeroSurge 2R15). Plugged into the surge protector is a 20 foot length of shielded, 20A power cord. Plugged into that is a C.E.A. high isolation transformer (2000VA, 0.001pF coupling capacitance). And, finally, plugged into that is a commercial-grade power strip into which I plug my equipment.

The LessLoss site has a lot of information about the theory and construction of these cords, and Liudas Motekaitis (who also uses the anglicized version, Louis Motek), LessLoss's designer/engineer, was kind enough to provide additional material. As it happens, LessLoss are developing a totally nontraditional power filtering device, the Firewall, that employs no active components, no transformer or inductors or capacitors because in the course of developing their  AC power cord s, they found that removing the (traditional) power filter from the circuit significantly improved the sound. They attributed this improvement to the elimination of the inductance and capacitance contained in the power filter, which tend to limit instantaneous current. Considering my own enlightening experience with these cords, it is both interesting and reassuring that LessLoss place so much importance on the quality of power delivered to audio (and video) equipment: “I am convinced,” Mr Motek writes, “that these somewhat 'boring' type of experiments [with AC power delivery] can mean much more to a system's overall performance and sound quality than switching components or signal cables, or even in some circumstances, speakers!”

Now, a high isolation transformer (HIT) such as mine filters the AC to some extent; when I first installed it years ago, I recall that it made the background quieter, or “blacker,” as they say. But Mr Motek suggested I experiment bypassing the HIT, relying on the DFPCs to do the filtering, to determine if eliminating this forty-two pound, unshielded inductor would improve the sound perceptibly. (Eliminating the HIT would also provide a ground connection.) I have to admit that I did anticipate this move would make an audible difference. And I believe it did (though not to the degree installing any of the DFPCs did). After all, it is logical that the hysteresis inherent in any transformer will tend to limit dynamics; just as it is reasonable that an unshielded inductor of high value will pick up every bit of EMI that passes its way. Nor did I notice any loss in background blackness without the HIT. And it remains out of circuit.