У Богнера, к примеру:
"To the left of the A/AB switch is the Output Power / 1/2 - Full switch. The function of this switch is to cut two powr tubes out of the circuit and knock the amp down to 60 or so watts. This enables you to crank the amp up to redline, and only hurt your immediate neighbors, not the ones at the end of the block. When using the half power switch, reset the ohms switch to 1/2 the actual value of the cabinet. (A 16 ohm cab should be set to 8 ohms, an 8 ohm cab to 4, don't use a 4 ohm cab in half power)."