i once built a VGA 1:6 active splitter so i could run 6 VGA monitors from a single input. i used NE5539 op amps as the video amps. what i didn't expect was the amount of heat these op amps generate. if you look at the output stage, you will see that it's single-ended, so the output stage is running as a class-A amplifier, and so generates a large amount of heat. if you can imagine 18 of these chips on a 6"x 8" perf board. the box got quite warm, and after about a year of use, the light tan perf board had darkened to a color like cedar wood or redwood. maybe i should have added a fan to that project....