One more thing.. while playing a few songs at high volumes today (more than 3/4 hu) the amp turned off for a 10-20 seconds a couple of times then went back on. I checked and it had a yellow light on. Not the red light for overload but a yellow light for "thermal". im not sure why this is overheating, i was playing for about 20-30 minutes max but really high volumes. sub output was at 0. is this an indicator than gain is too high. and is there a way for me to properly set gain without an oscillator.