Use two runs of 14 0 Romex solid core twisted together (from the hardware store) or Audioquest type 4 or 6 (using two wires for a side). The Audioquest has a good jacket. Be sure to clamp the cable securely to the chassis so that bending the cable won't break the solder joint (make a hook on the end of the wires if they go thru a hole in a board to keep them from popping out and shorting and causing a disaster that could kill someone).
