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
Hard to tell. There are so many variables. I was able to tell the difference between two different after market PCs and was not doing any kind of test. Did not even cross my mind there would be a difference. I had picked up a PC and it was not quite long enough. I had another longer PC being used another place that was long enough for both places. So I swapped them. I unexpectedly noticed a slight loss of bass and a higher noise floor where the longer cable was originally, when I turned the component back on with the shorter cable. So I put the longer one back on, and went back to the store and exchanged for the same longer PC.
For the thousands in attendance and the thousands watching from around the world, Ladies and Gentlemen, LET'S GET READY TO RUMBLE!!
JHunter: Did you try the PC on a source component or an amp? Hopefully both.
Here's the system:

Transport: Pioneer 525 DVD
DAC: MSB LinkDac III
Integrated amp: Plinius 8150
Speakers: Dunlavy SM-1
Cables: low-end XLO coax cable (DVD -> DAC); Nordost Silver Wind (DAC -> amp; very low capacitance and looks cool, although it's buried in the system); XLO ???? low-guage speaker cable (got cheap, looks cool and were heavy enough for my old Maggies).

I used the power cord on the Plinius as Albert recommended, plus it gave me 2 component's worth of change equivalent(pre- and power) for most systems.