[Reverend 7 Strings of Hate]

So basically a load box will change the level of the output as not to affect the sound quality, but make it so that the amp will be able to sound great at a low volume?

no, the load box is if you dont plug it into a speaker cabinet. basically you have to have some sort of speaker or a substitute (load box) if your recording direct from your head. If you have speakers plugged into it like normal, you dont need a load box, if you have speakers plugged in you can still record direct too, but if you dont have speakers plugged in, THEN you'll need a load box. if you turn it on with out one of the 2 plugged in, it will overload the amp and make it explode and light the house on fire

What you were refering to was a hot plate. It basically lets you get the the power tubes cranking high, but you dont have to have the speakers spit out all the extra volume like you described