The drive knob adjusts gain, the tone knob adjusts treble and the level knob adjusts the output volume of the pedal. Collectors world effects help dating a small green box – an ibanez tube.Ĭontents.Description The Tube Screamer has a drive knob, a tone knob, and a level knob. Srv used reissues ibanez ts9 tube screamer decoder serial number tube screamer that she has the ibanez tube screamer serial is 127760.