I just purchased a Hartke A100 combo with the 15" aluminum driver. yeasterday after band practice I turned off the amp and reached back to unplug the power cord to pack up and found the amp section to be quite warm to the touch. Volume was at about 6.5. We do play pretty loud. Is this normal? Maybe I need a fan pointed at the rear of the amp section? .... thanks for any info...btw this combo kicks!