How do I keep my cats off my amplifier?

Since my amplifier is too large for an equipment rack, I keep it on a seperate amplifier stand. There is nothing above it to keep my two cats from climbing on top when it is turned on, which they always do, attracted by the warmth. At first I didn't mind until my Rotel RMB-1095 Amplifier shorted due to a build-up of cat hair falling inside. Now my front right channel is gone. I just bought an Integra Research RDA-7 to replace it.
Is there a good way (short of the cat pound) to keep them off?