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Stage III Concepts A.S.P. Proteus power cable Review

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It’s not Just a PC – It’s A Component

Let’s start with some perspective. The Stage III power cords, especially the Proteus, the subject of this review, and its siblings at the top of the Stage III pantheon, are not for the faint of heart. We’re not talking about any other power cords that purport to improve over stock cords. We’re taking about power cords that compete at the very highest echelons of esoteric audiophile stock. The competition includes Nordost Odin II, Tara Labs Grand Master Evolution, Stealth Dream V16 UNI, PranaWire Avatar II and Siltech and Elrod entries; and this doesn’t even get to the “affordable” high end cords like the JPS Labs Aluminata, Synergistic Research Galileo, Silent Source Music Reference and Shunyata Sigma NR. We’re talking about power cords that retail at $12k plus, depending on length.

In the pecking (pricing) order of Stage III power cords, the Proteus fits in just under the Leviathan and above the Kraken, for which there have been several reviews of the two that you may want to check out for perspective. The Leviathan was designed to be the main source of power for your whole system and the Kraken to address the needs of high power amps. The Proteus ups the ante on the later. I wasn’t able to compare it head to head with either the Kraken or Leviathan, both of which are “monsters” in name and physical characteristics, but the Proteus, despite its name, which is derived from the name of the original Greek “old man of the sea,” is definitely a monster itself and clearly meant to be used with power amps.

Weighing in at approximately 17 pounds each, the Proteus cords need to be rested on the floor. They will easily pull a typical component right off the rack. In my case, they were intended for my Electrocompaniet Nemo monoblocks, the Electrocompaniet Nada monoblocks, and the Pass Labs Xs 300 monoblocks, all of which are situated on low amp stands. Here’s some data from the AAudio Imports website, who is the U.S. distributor for Stage III:


A.S.P. PROTEUS power cables employ 4×2 heavy-gauge Cryo-treated, custom slow-extruded silver/palladium AeroStrandUltra™ ribbon conductors.  Air dielectric with FEP Teflon air-tubes. Multi-layer shield with H.D.A. 100% radiation invulnerable foil + plated copper braid.
Geometry consisting of 4 individually damped and shielded stacked dual conductors in a quad helix configuration + heavy gauge plated silver ground wire shielded with silver plated braid.
Multi-layer construction with soft-polymer tubing + HDA alloy/ceramic/ferrite extreme mechanical damping/shielding layer.  Custom, hand made proprietary polymer/fiber plug + cable housings.


My Experience With Power Cords

Like other cables where you have to take one out and insert another, power cords are fiendishly difficult to evaluate. Performance-wise, it’s especially tough to have to decide what to do about cables that somehow cause a perceived increase in volume. Has it cut something out or added anything? What the heck was that piece of music supposed to sound like anyway?

It’s important to remember, however, that there is a fundamental difference between a power cord and signal cables. As Caelin Gabriel of Shunyata Research has observed in another space:

“A speaker cable conducts an audio signal from the power amplifier to the speaker. The distance is quite small, on the order of a couple of feet to several feet. The quality of a speaker cable is determined by how well it can transmit the signal from the amplifier to the speaker without alteration.”

“A power cable on the other hand is not transmitting a signal. It is conducting A.C. power and its sonic superiority will be determined by its ability to deliver current (steady-state and instantaneous) and its ability to deal with the EMI effects of the components to which it is attached.”

“Since a power cord is composed of a hot and neutral wire that the component sits between, a change in the length of the cord will increase the size of the “buffer” around the component. In general, I would not recommend a power cord that is shorter than 3 feet or 1 meter in length.”


Since, in this sense, your AC-powered component sits “between” the power cord feeding it, the design and parts used in the component affect the way the current flows in through and back out of the component. Viewed from this perspective, your components are not “fed” by the power cord but interact with it. But I digress…

Here is a partial list of the power cords I have significant experience with:

Transparent Reference Power Cord

PS Audio Statement SC

Nordost Odin 1 and Brahma

Isoclean (various)

Lessloss DFPC Original, Signature and Reference

From my perspective, what I have is average experience with a range of power cords, but I’m not close to being an authority. In particular, you will note that even though I’ve had several uber cables for my speakers and components, the list of uber power cords is short. A number of years ago my ears settled on Lessloss power products, and I’ve stuck with them. Hence they will be my primary source of comparison in this review.

7 Responses to Stage III Concepts A.S.P. Proteus power cable Review

  1. Mike Johnson says:

    I am puzzled, but interested in the improvement you speak of with the Pass Labs Amps. I have been told by Pass Labs that aftermarket power cords make no difference in their amps, due to their design. Other Pass owners have also stated they heard no difference in upgrading power cords on their Pass amps. You do not agree with this recommendation ?

  2. Ed Momkus says:

    Hi Mike – I’m familiar with the fact that Pass states that PCs don’t make a difference with their amps. Though that has generally been my experience with tonality, speed, attack, decay and most other Pass amp characteristics, on a few occasions I have heard very subtle changes in soundstage width with some PCs I’ve tried on Pass amps.

    Quite frankly, I was at a loss to explain my experience with the Proteus on my “big” amps. That is why I felt I had to be very specific about the effects with each amp playong different types of music. The results did not match my original expectations (prejudices?). Furthermore, I don’t know whether the results would have been different if different Pass Labs amps were involved.

    The only other thing I can say is that the differences, though clear to me, were still subtle. I know there are many people (normal non-audiophiles) that would not acknowledge any difference, and probably a good number of audiophiles who say the differences were too subtle and subjective to be reliable.


  3. Bill says:

    The improvements you heard are similar to a review of the Siltech Ruby Hill, by another reviewer. Both have in common, heavy silver alloy conductors. I find it interesting, but 18K is not my budget range for components.

  4. Tim says:

    Your kidding ….right ?
    Earth to audio…earth to audio…
    Jeez : )

  5. phil says:

    More that a amp, preamp and speakers and this is a power cord. This is what is killing our hobby and reviewers go along with this farce and promote it.

  6. Tom says:

    No power cord would be found superior to another in a blind test. The fact that sighted tests reveals differences is a great example of the confirmation bias in full display. Even with the obvious differences present in speakers, Harmon labs has shown differences in preference in sighted testing versus blind testing. How could a power cord somehow overcome hundreds of feet of 12 gauge solid copper house wire? Wow…

    • Dear Tom,

      Thank your for your readership and comment. I’m not sure I understand you: You are visiting a web magazine purveying the use of audiophile-grade products. You have no need to convince me or our staff, for we know what we hear.

      Instead, I encourage you to invest in just one premium power cable and use it for a month. Then, replace it with your generic power cord. See if you don’t miss the performance of your system with the premium power cable.

      I look forward to hearing from you again.

      Constantine Soo

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