A few weeks ago I purchased a Power Plant 5. I began by connecting my source equipment to it, including the DS DAC and C-J preamp that use for most of my listening. I could not connect my two amps because I did not have long enough power cords (the amps sit close to the speakers, not in the audio rack). For several years I have been using a Shunyata Hydra Alpha 6 conditioner for the sources and a Hydra Alpha 2 for the amps.
The most noticeable improvement I heard was more realistic instrumental timbre and sound of voices. Other changes, less striking but apparent on careful listening, included better separation between instruments, tighter bass, and more “toe tapping factor” (or PRAT as our British cousins like to call it). Overall the effect was to clean up/tighten up the whole sound somewhat. No question that this was an improvement, but I was not sure that it was great bang for the buck.
The longer power cords (Cullen Crossover Series) that I ordered finally arrived, so I could power the amps from the P5. Doing this gave two significant improvements. I am hearing many additional details that were previously covered up. Even with very familiar recordings I am catching musical content that was not audible before, and I really enjoy this. Tone colors are also more realistic, even beyond what I found with only the source components powered through the P5. The bass is a tad tighter also. As the power cords have broken in, these changes have remained and the soundstage has gotten wider.
All my equipment draws about 400 watts when running, which is less than half of what the P5 can produce. So I have plenty of headroom, which is good. At least one reviewer preferred the sound with only source components connected to a P5. I suspect this may be because his amps drew more power and pushed the P5 close to its limit.
I should add that the power from my utility company is probably better than some people have, which means that the P5 makes less of a difference than it might. I was running my Hydras off two dedicated lines, one for the sources and another for the amps (now everything is powered off the P5 from one dedicated line). As an experiment I plugged the P5 into a non-dedicated line and looked at the power coming it. The built-in oscilloscope showed a pretty decent sine wave, although not perfect (tops and bottoms of the waveform were a little crunchy). Incoming voltage is consistently very close to the official 120v. The P5 does the reduce THD considerably (2.something to .1).
So the P5 is a keeper. Thanks, Paul & Co.!