does anyone know what this means? I was talking to a friend about my svt4pro and how it doesnt have the power it should right now and he mentioned that my tubes could be out of bias. I understood what he meant but i wanted to get more opinions on what my problem could be. Here is what happened. I was jamming with my back up bass at practice. after a couple of songs i switched to my regular bass and i noticed it didnt have the power or volume that it normaly should. i cranked the main volume andthe gain to full and no significant change. Before if i turned everything up i wouldnt be able to carry on a conversation in the room but this time the amp had no power. I thought it could have been a dead battery in the bass so i changed that and nothing changed. TO compensate for the problem I had to boost the output gain on my compression unit. ( i dont use the 4pro compression) So this is my problem, could someone help?