emg compression issue

i'm presently playing a gibson epiphone lespaul style bass that has two emg select pick-ups, bridge and neck positions. although both produce good tone, would anyone be able to tell me why the tend to compress when i turn them all the way up? i've yet to find an amp that can handle the compression they put out. it pisses me off that i can't just crank my guitar without getting this boomy, ****ty sound out of it. and don't suggest turning the pick-ups down, because i can do that, just proves hard to adjust them in live settings cuz i have to go the top and then come off it until it stops compressing which, needless to say, wastes time and i'd assume pisses off the crowd by the end of the nite. anyway, if someone has had similar problems, or knows of what might be causing this problem, could they help me out? thanks for any input, god bless.

 

hey dudes,
understood. bought it second hand, had no idea what the pick-ups were like. probably my own fault for not looking into them. anyway, anyone wanna buy a les paul bass with two emg selects? haha