Hey all, here's my situation. I just picked up a Marshall JMP-1 preamp and a 9100 power amp and as usual for a Marshall it's got 16 and 8 ohm speaker outs. I've got 3 2x12 cabs all of which are loaded with 8ohm speakers. Is there a way to wire one of them to accept both the 4 ohm (both speakers) and 2 8 ohm outs for the Marshall. Do I need a switch of some sort? I'll probably use one of my Bag End cabs as its got room on the jack play for two more jacks. Any help anyone can provide would be most appreciated.