ok, so i have been running a GK 800RB and an old SVT410E (250 watts @ 8 ohms) for 2 years with no problems. the cab has to be around 15-20 years old, original speakers.. etc.. so i blow my first speaker out of it last night and tonight i use an Ampeg 410 that was 600 watts @ 8ohms and i'm not sure the model. the issue?? my GK sounds lifeless. i can't even compete with the geetar, whereas my lower rated 4x10 kicked major butto. It sounds super farty, no oomph, no nothing. Is the problem because the cab is rated for more power? did my pickups take a dump? i checked my cables and they were fine.. i'm lost. My head has powered an 8x10 and i know a lot of people use this amp with no issues. what happened?