Musings on Switching Power Supplies (LPS for Oppo / DirecTV/ Radiance)

So, this whole story begins about a couple months ago when I was watching a satellite television show on my HT system.  While I was watching, I noticed that my Oppo bluray player was still on (I often turn everything on in the beginning to warm stuff up and/or listen to music).  Well, I hit the remote button to turn off the Oppo and a weird thing happened.  The sound got a little bit better.  It lost a small bit of that digital “solid-state” harshness / brightness.  I then thought, “wait a minute, something is going on here”.  The next thing I did was, even though my Oppo was powered off in “stand-by” mode, I went and just unplugged it completely.  The sound actually got a tiny bit better after that.  Now I have read postings that say switching power supplies can cause noise in other devices when they share the same circuit/outlet.  I never really gave it much thought, but apparently this is definitely a thing.  My Oppo is plugged into the same outlet as me left surround amp, which is a completely different circuit than my HT processor and other amps.  However, the switching power supply in my Oppo BDP-103 was still causing havoc in the system!

I have four dedicated 20 amp circuits for my HT equipment.  I also had two other devices that still contain switching power supplies:  DirecTV Genie satellite receiver and a Lumagen Radiance video processor.  My DirecTV was plugged into the right surround outlet and the Radiance was plugged into the same outlet as my Krell S1200 HT processor.  So the next step was to pull those out and connect them to regular house outlets (which are different circuits and not even in the same subpanel).  I could see immediately that I lost some of the video quality through HDMI.  The picture was not as sharp and it introduce a little bit of noise into the image.  However, it did improve the sound even more (got rid of more of that digital harshness).

So what to do next?  Well, of course get rid of all these switching power supplies and, somehow, implement linear power supplies!