I finally had a chance to test out my new Puritan Audio PSM 156 in two of my systems.
The effect of the PSM 156 was very apparent - a silent black background with clearer ambient sounds from the room acoustics in the recording, improved clarity, detail and soundstaging. It felt like a veil had been lifted between me and the musicians. I heard new subtleties in very familiar recordings and greater detail with less smearing of the edges of the high notes of the piano and soprano sax. Certainly a big improvement over no power conditioning or filtration.
I then compared it the PSM 156 to my PS Audio PP3 and PP12. The PSM 156 clearly bested the PP3, but the PP12 was much closer. The PSM 156 was a little smoother sounding than the PP12 with slightly cleaner articulation of the high notes of the piano. I would give the PSM 156 the edge over the PP12. They both sound good, but the PSM 156 sounds a little better. It is not really a fair comparison because my PSM 156 is not broken in, and the PP12 is. The PSM 156 is bound to improve.