I also have an HK receiver/furnace...man that sucker gets hot. I noticed it has a small PC fan inside, but I've had it up to egg-frying temps and never been able to get it to kick in. It just seems to like to sit and smoulder...

Do the Denon's run cooler? and technically speaking, is a cooler-running receiver more efficient? (I'm thinking of that stat that says a lightbulb gives of 95% of its energy as heat and 5% as light, and wondering if the same thing applies here...)