For months I'm playing a lot with this tiny amplifier. It is 12 volt capable, low watt, yet ultra efficient power amplifier that very suitable for car audio application. It producing high quality audio with flea watt that most any mid-range or full-range speakers can accept. Previously, this auto power-on amplifier is controlled by using a mechanical relay. It is okay and not any single problem occurs. But to make it less mechanical things, I built the simple solid state relay in it.