Hello, I'm new here and I'm also a complete novice to bass playing, so maybe my question would seem stupid. But the case is, today I turn on my practice amp and I hear that low continuous sound. No reaction to anything that I do with my bass. The amp just sits there and keeps humming the note so well that any singer would be jealous. What could go wrong? Could it be that I stuffed it up by pulling the connection cable out of socket while the amp was turned on? It happened once I didn't realize I walked off too far away playing my bass and the cable popped out. Apart from that, I didn't even touch it that often except the on/off switch.