Anyone know of a good, quiet, small fan?

Hi folks, I'm trying to increase the air circulation around my amplifier in its equipment cabinet. the back of the cabinet is completely open, and it's a pretty cavernous space, but I think heat dissipation could use a little assist. All of the fans I've found locally are too noisy. Ideally I'd like something that I could mount on the underside of the interior of the cabinet above and behind the amplifier, that would pull hot air out the back. Any good suggestions?