I acquired a lightly used BA-115 last month for rehearsal use, sounded good enough paired with a SansAmp RPM and compressor and I was reasonably satisfied. However as of late it's been distorting, dropping in volume, and breaking up if I really dig into the bass and hit the strings hard. this is evident at any volume, and, if played with a light touch, doesn't seem to be an issue. Has anyone else had this problem? is it something with the tweeter? I'm really ignorant when it comes to the inner workings, especially of a little solid state like this, so any help or advice would be appreciated.