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.
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.
Never tried Audience, but can recommend Grover Huffman. They do everything you mention and come with a 60 day guaranty and you'll come in under your budget.
You might experiment with the cord on your CD player first. A lot of people here use Shunyata cords that are designed to quiet digital sources (older ones had the "VX" designation). I've used them myself and found that they made a big difference in the background silence of my system. I didn't like the Shunyata cords on my preamp or amp, though, and felt that on those components the overall sound was more compact and veiled with the Shunyata. Your experience may be very different, of course.

$500? Try for a TG audio SLVR or 688. They often show up used here for $2-300. TG has also been re-instituted and is selling new version ( I have not heard the new ones). SLVRs and 688s are absolutely silent and
are great cords in all respects, too. Another cord that is just as silent and also sounds great on my EMM CDSA player is the Stefan Audio Arts Endorphin cord ($379 new, a giant-killer IMHO). See my recent review of a Rudistor headphone amp in the Amp review section for my comments on it.)
The Stefan cord is great on my CDP and Capri preamp too.
Also, check out the Blue Circle BC68 mk2 ... basically a SUPER silent power conditioner and cable.

Also a HUGE TG Audio fan... but the BC68 is quieter... ultra black backgrounds...

Big stage, depth, with great dynamics too... (the BC68 mk2)
May I have a suggestion? A power cord that gives a quieter background means it
has superior shielding against electrical interference. So why don't you contact a
few cable manufacturers and ask them to provide you with the design spec and
the test result of the shielding or noise rejection capability of their cables. Even
the regular coax lab cables like the RG58 and RG59 have design spec, a carefully
designed power cord costing $500 a piece should have even more detailed
design spec and more complete test results. Once you have that information,
selecting the right cable for your requirement should be much easier.
Hi Rbc

I had an Emotiva ERC-1 CD player and I used a My Audio Cables (MAC) HC power cord on it. The MAC HC power cord contains 3 conductors of 10AWG clad oxygen free copper stranded wire that are braided.

After letting the Emotiva ERC-1 play awhile I noticed a quieter background and improved sound clarity. It wasn't an insane leap in SQ but I did hear a change for the better. The difference I heard made me stop what I was doing.

I know the My Audio Cables HC PC is a lot less than the $500 you want to spend but it may be worth a try. My Audio Cables also makes the Burly PC which is about $300. I don't have this beast installed on any of my components because I just can't spend $300 on a PC but I held it in my hands it felt like I was holding beefy snake.

Good luck with the PC cord search. I just thought I'd share some experiences and thoughts.