Earlier I proposed an experiment to replace a switched mode power supply delivering a nominal 12-Volts DC for a 12-Volt battery in a Faraday cage. The target CD transport is a Sony Univeral disk player with HDMI output.
My Windows laptop has an HDMI connection. Does anybody know how to capture CD playback on this HDMI connection to a digital file on the laptop. If so, this should be able to tell if there is a bit-wise difference between power sources when playing back the same CD. Assuming the same starting position!
If the two match bit-wise, any sound quality difference would surely have to be caused by the injection of electrical noise into other connected components by the switched mode power supply.
Obviously, if I do hear a difference, I have satisfied one person (me) that there is a difference, especially if I hear it consistently in a blind comparison.
But I can also hear the objections. My mains is about 250-Volts RMS, not 110. My grid is not like yours. (Mine is geographically the world's biggest, going from the Northern tip of Queensland south down the Great Dividing range then under the ocean to the hydro-electric generators in Tasmania). There's no big industry near where I live, only an electric light rail several miles away, Even the ultra-low frequency submarine communications base has been dismantled.
If I can't hear a difference, the CD transport will be too cheap, or my ears too old, or the rest of my gear too unresolving.
Thoughts?
