Pentode vs. Triode....Difference?

[jim p]

I posted earlier what the changes were in the amplifier that I modified to have both pentode and triode mode. An analogy to what the triode vs. pentode mode is like would be dribbling a basket ball with the output transformer and speaker the ball your hand the output tube. In the pentode mode it is like bouncing a well inflated basket ball easy to bounce and will continue to bounce by it’s self for a while when you stop (the bounce being the harmonics or high frequencies you hear). While the triode mode is as if you took air out of the ball, you have to work harder to bounce the ball and it stops quickly if you stop. So in the triode mode more power is lost across the output tube with less power to the speaker and the speaker is stopped quickly by the action of the tube (lower harmonics you hear as less high frequencies).