One I have found that has an almost spooky-quiet background is the VH Audio Air-Sine cord. They tend to sell for around $400 on the used market in standard lengths. Vocals tend to sound so real with this cable on either source or amps.
Power cable for quiet background
I am having Audience powerchord for cd player and tube int amp. I need suggestion for an upgrade that does not alter current characteristic of the system. (open and detail and great soundstage), and would give a more quiet background. Looking for $500 each. New or used.