O.K, I have an Ashdown Electric Blue 15" 130 watt combo. I'm well pleased with it and it's very loud for it's size. I've been offered an Electric Blue 150 watt 15" for a silly price and was thinking about stacking them and using the line out of one into the input of the other. They are identical sizewise,and lookswise, the only difference being the 150 has the sub- harmoniser. Would I get much more headroom using this setup for bigger gigs? Any potential problems?