#1
i ned help about amp heads like can you use just an amp head alone or do you need a cab to go with it if doesn't does it reduce the amount of power
#2
no a head doesn't have speakers, just the preamp and power amp. if u use a head without a cab of some sort things inside the head can get messed up really bad. and it doesn't reduce the amount of power. but yeah u definately need a cab.
#3
The cab is a nessecity along with a head. The head itself is what creates the noise, and the cab is what puts the noise out.

Similar to a personal CD player, the Cd Player generates the noise, but you wont hear anything until speakers are connected.