The +5V connection shown is going to the KMotion board mounted under the SnapAmp. If you have a KFlop board you should apply +5V power to the Molex connector in a similar manner. SnapAmp+KFlop draws too much power to be powered directly from the USB cable. Make sure you also remove JP3 on KFlop which selects USB power. SnapAmp gets +5V through the 16 pin ribbon connector so no other low voltage logic power is required.
When attaching a SnapAmp to a KFLop also be sure to attach the 18 gauge black ground wire to the screw hole marked GND on KFlop.
TK