Usually the higher priced squirrel cage fans seem to be more durable as well as quieter. I've used these in high power HF tube amplifiers. In this case the bottom of the cabinet is pressurised and the air moves through a ventilated tube socket,up around a chimney enclosing the tube then out the top of the cabinet. This seemed to keep very big and very $$$$$ tubes happy.
Looking for Silent Fan Cooling f my ARC Tube AMP
I have my ARC tube amp in a corner. I like to stick a fan behind it . The one from radio shack worked great but made a little noise. Any suggestions . Thanks to all !