I have an Ampeg B2 4 X 8" combo. I have a problem with the input jack. I had it replaced a year and a half ago and I need to have it replaced again. The jack is kind of a plastic barrel that has 2 metal spring strips that make contact with the guitar cable. The metal strips are thin and, evidently, become fatigued and won't hold the plug tightly enough to transmit the sound. Has anybody else had this problem? How did you solve the it? It doesn't look like a Switchcraft jack will fit...HELP!!