When I hear the term "Patch Cord", it brings to mind those cheap L/R cables with the "walkman-style" 2 wire cord that is tossed in with many camcorders and DVD players.
You should avoid these.
Your "interconnects" should all be made with coaxial cable (at least as thick as your CATV coax).
Going from your pre-processor to the amp, the signals are weak, line-level and need a coaxial cable to prevent other signals from interfearing.
The nice thing about audio is that nearly any good cable with RCA plugs will work fine.
If you are running 5 channels to an external amp, you can actually buy 2 packages of the "L/R/Video" cables sold through Best Buy and Radio Shack. While the plugs all have different colors, the coax is all identical 75 ohm coax which works fine for audio. And the bundles really help cut back on the "cable clutter".
You need coax cable (w. good shielding) but the conductor doesn't need to be as thick as a proper CATV cable. CATV, DSS, & video cable need to transmit much higher bandwidths (so they need thicker cable). Audio interconnects require significantly lower bandwidth & don't rely on a standard impedance (like 75ohms for video cable). IMO, any cheap male-male RCA coax cable will work. Wrap them up in braided nylon shield & heatshrink to enhance the placebo effect...