I have tried replacing the stock power supply for several pieces of gear with a 5V/3A iFi iPowerX. For an iFi iPurifier SPDIF and a Bluesound Nano I convinced myself it sounded better than the iPower2 that came with the iPurifier or the 5V usb phone cube that came with the Nano.
I tried the iPurifer because I was having hand shake issues between a Node N130 and a Chord QuteHD DAC. The iPurifier with the stock iPower2 supply sounded worse than without it. Trying the iFi iPowerX improved the sound a lot. This was in my main system with some power conditioning. I ultimately found the intermittent handshake problem was due to a faulty BNC/RCA adapter on my coax cable. Once that was resolved I no longer needed the iPurifier and sold it.
I kept the iPowerX, and have tried it in other 5V applications, like the Nano in my smaller office system. After swapping the iPowerX in and out multiple times I found it offered greater clarity on the leading and trailing edge of notes and noticeably better soundstage presentation with the Nano. Both the stock and iFi power supplies were used in concert with a decent power conditioner in this commercial office environment with unknown AC quality, but lots of computers, fluorescent lights and dimmer switches around.
Interestingly, I did not experience the same positive result with the iPowerX and either a Chord Qutest or Mojo2 DAC, either at home on a dedicated power line or in the office environment. In fact I thought the iPowerX sounded worse than the stock Chord switching supply. YMMV.
kn