How to thwart cats

A question for cat owners: I just had to send my BAT VK-300x integrated amp back to BAT for what I assumed was a warranty repair after having it for 3 months--it had begun spitting out white noise and then sent sparks out the top grill. It turns out in fact that it was full of cat hair and--putting it as discreetly as possible--other cat-related material, which had caused it to short out. The cats have long used my audio gear as a sort of large, centrally heated cat bed, but those days have now ended. Does anyone have any suggestions on how to keep cats off your gear?

I keep the VK in a rack , with about 4" of clearance from the shelf above--it would be easy enough to add a piece of nonresonant material underneath it to reduce the clearance and thereby catproof it, but I'm wondering about the other components too.

Any thoughts? And no, throttling the cat responsible is not an option.