Well, I manually set the fan to 2 when I’m going to use the amp heavily. It’s a bit noisy but acceptable to me. 73 Carl Yaffey K8NU Recording studio. cyaffeyNO_SPAM at gmail.com 614 268 6353, Columbus OH http://www.carl-yaffey.com http://www.grassahol.com http://www.bluesswing.com