I almost forgot...
Shep, the fan I got was for somewhere between 110 and 120 volts. I cannot remember exactly. So, yes, the fan is made for that much current. Computer fans run on very little current. Sometimes they run on as little as 3 volts. It is just a matter of the electronic component being matched for the specific duty. In this case, Mesa chose to use a fan that ran on the same power as the amp. The industrial fans are actually heavier duty than the little computer cooling fans and typically last longer. The only drawback is the added weight. It would suck if your little computer fan that was wired to the PCB fried or fried the board. In this application, you just replace the fan if it quits. If you had a low voltage fan you would have voltage regulators and stuff that would increase the cost of your amp only to help it find yet another way to break. Then the replacement would take a little more skill to unsolder and resolder your fan or even replace your PCB and/or other circuits nearby. The nice thing about using a larger fan and power source is that the wiring is easier to work with because it is larger too. Mine was spliced and soldered and shrinkwrapped together for a nice neat package that still fit in the fan housing. Those little wires of a low voltage fan can be a little more difficult to work with. I hate having to deal with those smaller than 20 gauge wires especially the solid ones. It is too easy to break one or not get a good connection. At least with a nice sized braided wire you know you are getting positive connections.