Also, more power (turning gain control up) isn't always better. Some of the best sounding sound systems I've heard never had the gain control up over a quarter. It all depends on the ohm's and the componants. I prefer quality over volume.
Here's how I adjust my gain control. I set the volume to just above daily listening. Start the gain at the bottom and slowly raise until it distorts, then back it off until it's clean. Then, I turn the volume up just past loud comfortable until distorts. Then, back it off until clean again. All set.