Today, my bass wouldn't play out of my amp. I was like "hmm", I took the cable out and touched it's plug against the strings and my amp reproduced the "eeerra zaaaa" sound, so I knew it was my bass. I bought cheap cables, and they always cause the little thing around the input to get loose. But I'm pretty sure the input is broken, or somehting is. Any idea how to fix it, or what may be wrong if I am mistaken?