I'm having a lot of problems with my cab, a GK MBE210, and my head, an Ashdown LB-30. Any time that I really dig in when playing, the LB does its characteristic tubey breakup (master at noon, EQ as flat as possible, BDDI running a slight bass boost with 40% blend, and an LMB-3 with the output at noon), but the speakers in my cab just completely fart out and distort. It sounds terrible, and it's really having an effect on my playing, since I'm terrified that any hard pluck/pick could provoke the noise. What could the problem be? This happens regardless of whether or not my pedals are plugged in, so I'm pretty sure it's the cab; I just don't know how to fix the problem. New cab, maybe?