This is a mod that will have little effect IME. Inputs that are not selected are not involved. Better off to figure out how to eliminate ground-loops. Now this will actually reduce the noise floor. I have zero ground-loops in my system. Jet black background.
"Little" effect is precisely what I anticipate. As to inputs that are not selected not being involved, I recently raised this "question" elsewhere on the forum in a related thread (like RCA plugs, shorting caps, etc.) and was advised that (paraphrasing) theoretically they *are* involved and that shorting them can only help, albeit however slightly. Moreover, there have been some folks on this forum who have reported positive results by shorting unused inputs. Further, I did some do diligence by checking with the manufacturers of my gear (Golden Ear and Musical Fidelity) and both state there is no harm in doing so, although also state there shouldn’t be a noticeable benefit. This is a low cost attempt ($20?) on my part anyway, so I shall see.
Besides, I’m a big Joni Mitchell fan (a Grateful Dead head nevertheless). She so eloquently puts it (Amelia)
People will tell you where they’ve gone
They’ll tell you where to go
But till you get there yourself you never really know
Where some have found their paradise
Others just come to harm
Consider this my holiday musical gift to all:
https://www.youtube.com/watch?v=1N7gPcCgkZU