From the Ampeg B4r owner's guide. 13. LIMIT DEFEAT: The B4R employs internal limiter circuits to help keep the power amplifier's out clean at extreme volume levels. (All amplifiers may begin to clip their output signals as they approach maximum output levels, resulting in potentially speaker-damaging distortion.) These circuits may be disabled by depressing this switch. This may result in an increase in output power, but also increases the possibility of distortion. Use discretion whenever playing with the Limit circuits off. AND From the Ampeg B2re online owner's guide. 9. LIMITER: The B2RE uses an internal Optocoupler Limiter to assist in keeping the power amplifiers output clean at extreme volume levels. (All amplifiers begin to clip their output signals as they approach maximum output levels, resulting in distortion which may damage your speakers.) To engage the Limiter, depress the Limit switch. Whenever the amplifier is at full power, the adjacent Limit LED will flash. This is an indication that the limiter is keeping peak signals from clipping the output. NOTE: Playing at full power with the Limiter off will give you increased output power, but the sound may be distorted. Use discretion when playing without the Limiter. So as an owner of the B4r I should keep mine out and any owner of a B2re should keep theirs in, so they do not send out variable amounts of Wattage and potentially harm their speakers. Is this correct? And why would Ampeg do this? Cheers.