Although we list two different numbers with "Amplifiers Disabled" and "Amplifiers Enabled", these are not "modes" RidePlayer can be put in. This essentially just means if you're using the Line Outs (not amplified), RidePlayer will pull 3A. If you are using the Speaker Outs (which are amplified) you will pull 20A.
The amplifiers are always enabled as both sets of outputs are always hot. Power is drawn based on which set of outputs you actually connect to external amps or speakers.
Using combination of speaker outs and line outs would fall somewhere between those values.