Hello, I am totally new here but the reason is I need to find a solution for my problem. I have a JBL subwoofer and a SAL amp in my BMW. The amp is connected by Hi level input connector and works great. But each time I turn on the head unit I have to manually disconnect the connector and put it back in to have the bass from JBL sub. Wires are set up good while my previous Sony amp worked fine. Any reason why is the amp doing this? Thank you very much. Padrew