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PC Challenge Test Results

As a result of the "PC challenge" thread, I've now had a chance to put a high-end aftermarket PC to the test in my system. First, sincere thanks go to Albert Porter for helping to set up the test, and especially to Jim of Purist Audio for his hospitality in loaning me a PC. Jim also was quite gracious about how long the testing took.

Jim sent me one of his Dominus power cords. This PC clearly uses very, very high quality components and the level of construction appears outstanding; this is certainly a PC at the highest level. I'd guess that you could jump-start a car with this wire! I don't know if this cord costs $50 or $5000 (bet it's closer to the latter), nor did I want to, to avoid possibly influencing the test.

My initial listening took two approaches. After having powering-up the cable for 72 hours as was recommended, I listening in a very relaxed manner, without trying to identify any specific differences. Did my system seem more or less enjoyable than I remember? The answer is yes, it did seem more enjoyable; there seemed to be less "stuff" getting in the way of the music perhaps, a clear although not huge difference, and there also seemed more of a foundation to the music. The question then became whether or not I could pick out specific differences? Again, compared to my recollection of the system sound the answer is yes. While the changes were relatively subtle there appeared to be more and better bass (slightly deeper and more defined, more of a visceral impact) and the vocals somewhat more natural - less "in your face", perhaps. The lack of bass depth is an inherent shortcoming of my system, but the vocals had never stood out as a problem area before. Overall, the sound seemed more transparent, quite a feat given I think that's one of the primary strengths of my system. Bottom line for this part of the evaluation: the Purist PC definitely added to the system, although subtly.

Now, that being said there I had some very strong concerns on the above given that this was a sighted evaluation. It could very well have been that I expected and was listening for exactly those effects (not the vocals, though - that surprised me), or that my audio memory of the previous setup was flawed. I wanted to try some blind evaluations as a test. I have no ABX-type of setup, so was unable to conduct any tests that I'd consider truly scientific, but tried something that was informative nonetheless. With the help of my brother, we did some rapid-switch testing: he flipped a coin and either switched between the Purist PC and stock, or not. I typically listened for 2-3 minutes to the Purist before the switch/not-switch and an equivalent time after before deciding, and got 7 right out of 12 trials; we then tried it with the stock cable first and I got 5 out of 8. I've not yet hauled out my old statistics textbooks, but am pretty sure that this would fail most reasonable hypothesis (say, "there are sufficient differences (95% confidence level) between these PCs that I can identify them correctly 80% of the time).

So what does this mean? Nothing beyond that it appears, in my system, that I probably cannot discern any purely audible differences between my stock cord and the Purist. Any broader conclusion is unsupportable from my testing alone, although I do suspect that equivalent results would hold for the population at large. But - and this is a big but (no jokes, please!) - before the blind testing I did perceive an improvement in my system; for many, this is sufficient and they may gain a real benefit from aftermarket PCs. In my case, though, I'm better off adding a sub than investing in aftermarket PCs.

Cheers,
JHunter
jhunter
jhunter OP
45 posts
 
In response to Asa’s comments

1. I don't know many people with requisite experience in listening who also don't know that Purist cables, and particulary the Dominus line, are very expensive, relatively speaking.

I’m not sure what the point of this is, other than perhaps to imply that I don’t have a background adequate to hear what the Purist PC did for my system. Just because I don’t know the price of a particular piece of equipment (and I did say that it seemed clear that the Dominus was pricey; I just looked it up and found it lists for $1500), please don’t assume that I do not have the “requisite” listening experience, whatever that is. Perhaps I’ve not spent as much time listening to equipment as others, but have a pretty reasonable background listening to real, live music: 30+ years as a relatively decent amateur musician (well, maybe 20 years for the “decent” part, and some may dispute that!), hearing live, unamplified instruments 1-2+ per week on average.

2. You should be able to hear a difference on the Plinius in terms of bass registers, but, to be frank, your system, although well thought out, is not of the caliber to benefit from a cable like the Dominus PC or the like (eg. NBS Statement I on Pre's/CD, Electraglide FatBoy on amps, etc.)in terms of harmonic and spatial effect.

I have to admit that with a system running ~$6k or so (list), I haven’t spent much time looking to buy power cords at $1500 apiece. Anyone who would spend an equivalent amount on power cords as components is, to be very kind, showing questionable judgment if they feel that is a reasonable approach to upgrading their system. As I said, my personal $1500 upgrade would be a subwoofer, something that is unquestionably audible.

I was not shopping for a Dominus-level PC; it was arranged by Albert Porter, and very generously lent by Paul at Purist. While my system is not the absolute, it is really quite revealing and keep in mind that they chose the Purist as one that, knowing my set up, they felt would be a very audible step up from the stock cord.

3. Most people who would be interested in a Dominus-level PC already know, as Porter alludes, that NBS, Purist et al are very suceptible to movement. Whether you ascribe to the theory that the dialectric needs to re-form, or whatever, the fact is that, once moved, the cable needs at minimum 48hrs play-time to "re-settle". Absent that time - and I submit that its more like 100 hrs to get everything back - the cable will sound brittle on breath transients, lean on harmonics and phasey.

If you believe that the movement has an effect, isn’t it a coincidence too amazing to accept that movement does not leave the Dominus audibly better (if that is how it started), make it audibly worse or even just plain audibly different from the stock cord, but somehow makes the two PCs statistically indistinguishable within the limits of my test? That is, the breath transient brittleness, harmonic leanness and phasey-ness are induced in such a way as to precisely match the stock power cord?

Well-intentioned and well written. But again, with respect, I believe that the experiment - if it truly wishes to aspire to the rigors of ratio-empiric method - must be examined in light of these deficient variables. But, don't stop, keep going. The essence of empiric method is trial and error, and those erros many times occur in our original assumptions that underlie our experiments.

Thanks. I did go into this test with an open mind (never can tell what you’re going to learn), although my technical background led me to issue the “Power Cord Challenge” in the first place. I’m fairly well grounded in the scientific method, which is why I put the caveats regarding any broad validity or interpretation of my tests. I am satisfied that the results have meaning within my originally stated limitations, however,. Enough serious testing, though, for a while I’d rather just enjoy some music!
jhunter OP
45 posts
 
Sorry about the confusing responce to Asa - I'd noted who wrote what but that somehow got lost when posting. FYI, the paragraphs immediately following "1.", "2." and "3." are Asa's, as is the paragraph beginning "Well-intentioned . . .". All others are my response.

JHunter
redkiwi
1,092 posts
 
Any such experiment with audio gear is personal and contextual. In the end Jhunter decided his next dollars would go on a sub rather than PCs. That is the significant outcome of the experiment brothers and sisters - for Jhunter in his room with his current system. And thanks for sharing it Jhunter.

Others here find PCs to be more vital, and I wouldn't dream of swapping mine for a sub. Some here just don't want to know about PCs, for whatever reason. Jhunter's experiment proves nothing, but who cares - if it causes a few others to at least try PCs with an open mind, then great.
asa
662 posts
 
Thank you, JHunter, a well-measured response. As Redkiwi states, knowledge is contextual. I would also add that it is also the mind that hears music, not the ears, and in this context, knowledge is state-specific. We will have to agree to disagree, but thank you for addressing the content of my points. I look forward to your next foray.
pefstratiou
47 posts
 
Every posting on PC generates tremendous response. You would believe that this is all our hobby is about. Now we learned more variables. Pinching cords? Is this P(olitically) C(orrect)? What if the cord is less than 18(gauge). I suspect it is not even legal. But seriously folks, if power cords or similar tweeks are so important how come are used so inconsistently by professionals? I am referring to the recent NYC show and similar venues. You would expect the manufacturers to try to improve the final sound as much as they can. On the other hand, you see in some cases using the Michael Green Power company mains treatment which Home Theater magazine came out and said that it had a negative effect on a pure audio system. So, I think that business alliances play major role. And finally if every time you disturb a PC you have to wait up to 100 hrs to restabilize, one lifetime is not enough to conduct a definite comparative test. (Another good reason to make cloning legal).
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