When I use my car booster amp, I use a small mixer which besides allowing me to use up to 4 inputs, also brings the signal up to line input level (.5v-1v). The amp itself is rated at 160w total peak power, this in fact means that the actual RMS power is about half of this ie 40w per channel. This is plenty of power for the busking sessions that I use it for. I have the whole lot mounted on a small garden trolley and can just push it around.