"Why is it necessary to have eight Power tubes on a mono block amp?"
A KT88 tube is rated at about 35 watts per tube. That is why you need 8 tubes to produce 300 watts!
Can anyone explain what a power tube does inside an amplifier, eg kt88.
I know a tube is cool looking, and looks like a small lightbulb with many pins on one side and when it's turned on filaments glow inside a vacuum enclosed see-through curvy glass enclosure. I guess current flows in, goes on a journey, and then flows out.