Moinsen, since I don’t know much about Auto-Hifi, I would like to ask you for help: I have installed a JVC KD-R 401 in my trailer. According to technical data, the power should be 19W at 4 ohms per channel. At festivals I operate on this radio ITT-boxes, whose technical data are to be taken from the picture. Problem: At max. volume or from the very beginning the boxes start to distort. Battery voltage stable at min. 12.4V. My guess: The radio amplifier does not have g enug performance. Question: 1. Does a power amplifier make sense? 2. Do you have a recommendation for a cheap power amplifier? Thank you very much in advance. Greetings Oldwood64