Small circulating fan to cool amps


I have two tube amps that are on a rack system with wood shelves. Because of the space requirements of all the components on the rack, there is not as much space as I'd like to see between the top of the amps and the under side of the shelve above. Although I have not had any problem to date, I'd like to make sure it stays that way. These amps do throw a fair amount of heat. Has anyone had any experience with a small fan that could be used for ventilation? I looked at Radio Shack and although they had a number of small fans, the smallest and lightest ones were 12v. I'd much prefer to run off wall current, but I don't have alot of space in which to situate the fan. Their non-battery fans were just too big and heavy. Any suggestions?
frankm1
Thanks. Unfortunately, both units are just too large and heavy (appears the Sherbourn comes in just one size - the 3 fan unit and is 12v). I saw the same (3") fan at Radio Shack - I've got a pretty limited space - was hoping to some how attach the fan to the uprights on my rack - the fan(s) would need to be pretty light to do so.
A cool (no pun intended) way to do it if you have a couple inches under your amp shelf, is to cut a couple of four inch holes (or whatever the fan dia. is) in the amp shelf itself, and mount the fans to the bottom of the shelf blowing up at the amp's bottom, which if it's not solid, will provide sufficient air movement to keep them from overheating.

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I still think you should buy a 12vdc power supply and then you can plug the fans into the wall recepticle like you want to. Get one with enough amp rating to run all three off the same supply. Radio Shack should have them too.
Not sure of size requirements but check this fan out http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.jsp?SKU=50-1672&N=0