When ordering a power supply I know voltage is a factor "12 volt radio requires 12 volt power supply etc." and amperage very important for powering a linear amp that of course if it is a 12 volt mobile amp. Now say you are using a amp that produces 400 watts does the wattage of your power supply a factor in this particular situation such as 400 watt power supply for powering a 400 watt linear. I haven't heard any discussions about wattage and power supplies