What a godsend. I have been looking for schematics for years. I own 3 GBX amps (bottoms) and 2 drivers, one for guitar and one for bass. the only thing missing is the user manual, if one exists. I want to know what the Response (A_B_C_D_E) knob indicates at each setting. Again, thank you very much. Bogeyjack :dbtu: