I bought this amp from someone who had just got it back from the factory where it was completely brought up to spec and retubed. On the deck of the amp, it says to adjust bias of output tubes, turn screw counterclockwise until LED light goes out. The screws are turned all the way clockwise and lights have not come on. Will they eventually come on as tubes burn in? What's up with the bias adjustments on this amp? thanks much
