Think about a block of metal that's 19x12x22 inches that is hot to the touch but not so hot that you couldn't keep your hand on it. This is in your room radiating heat. For a typical listening room, this isn't terrible. Then there would be two for stereo. Another way to think about it would be to imagine a lightbulb array of comparable wattage -- the great majority of a light bulb's wattage is radiated in heat, not illumination. 600 watts of heat from an X600 would be like six 100 watt light bulbs. (Or one 150 watt light bulb, per the wattage cited in the above posts.) Notably, the heat radiated might actually decline very slightly as you turn up the volume, so long as you stay in class A mode, since more of the power draw would be consumed in making sound. Of course, it might get a teensy bit hotter when you start peaking into class AB. The X600 is a fine amp. Good luck.
