Pre / Amp RCA jumpers for NAD C356

I tried Audioquest and custom made Signal Cable RCA jumpers
but I heard no difference. I would say that NAD C356 sounded the best with the stock jumpers. Are there any better RCA
jumpers or I should just look for the good short pair of the
Interconnect Cables.
Had the C370 integrated

(1) tried the cheap route first. My findings starting with the worst first and going up in order :
- NAD stock stamped metal jumpers,
- Audioquest "mini RCA" jumpers
- other "cheapo" ICs with their crummy RCA connectors
- CARDAS copper stamped metsl connectors

(2) from my experience, a QUALITY short length psir of ICs worked much MUCH better. For me: = Van Den Hul with quaility RCAs

(3) What worked best overall, including better than swwapping in the quailty ICs as jumpers: replaced the stock wired-in power cord with a professional mod IEC receptacle and inserted a quality power cord (Furutech)
Try the anticable jumpers. I used them and found them vastly superior to the audioquest ones. They were only around $20 I believe.
I also think that Cardas is the marque to look to. I would get a short IC because the metallurgy of the straps is questionable at best.