First, if your amp can do this, find a Hard rock or Heavy metal sounding channel, then set the controls as followed.

Gain (or Drive) 10
Bass goes to 8
Midds go to 1 or 2
treble goes to 9
Reverb goes to 2

Thats for a Kill 'Em All tone. If you want the black album tone here is the settings; Again go for the heavy metal sounding pre set channel.

Gain (or Drive ) 8
Bass goes to 8
Midds go to 4 or 5
Treble goes to 6 or 7
Reverb to 1

Hope this helps! :-)