$20 XLR cables that sound good

Everything's riding through IC's. I'd begin by selecting well-built, well-insulated "middle-end" IC's from a reputable audio company. Your ears will reveal if it's a musical system match, really capturing the system's synergy.

You may also order two or three different IC types and return your least favorite(s). I'd first try connecting the L/R main channels through different IC's and play your best-known test sources. The best system match may jump right out or be less dramatic but definately better.

I practice basic connections care that also definately helps. That includes cleaning all interconnects, keeping connections snug, using short cable lengths, pugging and unplugging carefully, and running audio cables separated from any power cords.

Some manufacturer's can assist you to match IC's. What cables did they find worked best during the R & D bench testing processes?

For example, most of us have read several articles explaining that Mark Levinson uses Revel Ultima speakers for bench testing components during R and D.

I'm very happy with a Proceed AVP2 +6, matching AMP 5 and Yamaha TX-1 powered cathedral monitors (connected directly off my pre-out signals). All sources sound right.

For system synergy, I'd place Ultima's on top of my list should I ever have to replace speakers.

Audiophile talk is like music and it goes on eternally. There's alot of great info here. Ask the manufacturer what they used and include them in your order for 2-3 different sets to test on your mains first after checking the return policy.