Guys, one more question. In the instruction manual for the 550 it says to turn the gain knob clockwise until the set level light goes on, and then back it off two notches. There are two leds above the set level text on the amp. One right above, and the other about an inch higher. I tried this method today and neither light came on, and I had the master at fully counter clockwise. Which Led should come on? The lower one or higher one? Is the higher one for something else? It looks like it might be burnt out or broken, (knew I shouldn't have taken the floor model...)