How to keep my stack of Adcoms cool...

I have three older Adcom amps in my entertainment center (two GFA-555II's and a GFA-2535), and predictably, they generate a good bit of heat. I usually leave the door to the cabinet open, but I would like to be able to close it sometimes, as it gets in the way of my speakers, somewhat, when it is open. My thought was to install a couple of cooling fans (one sucking air in, and one blowing it out), but I am somewhat concerned about the noise. Does anyone know of any very quiet fans, or of any other tricks to keeping your amps cool?

Thanks, Tom.