Ok so for a while ive been using this customsound power amp behringer mic pre amp 115 and 212 cab wich built my self!! And an ibenez 200 gsm and all was fine but ive just had my shaftesbury ric copy restored all was well first off with ricopy then gradualy it started making a farting noise at first though one of the 12s had blown but Trying stuff to day if i got both cabs connected if farts but put each cab in seperate it sounds fine,gonna try ibenez in it monday,but i wanna use the ricopy as i got first gig next sunday,but would it be guitar or is the amp under powering with both cabs and a passive guitar??????