I have an Ampeg 2x10 and 1x15. They both "handle" 400 watts. Both are 8 ohms. How much power should I be using? 400 exactly? More than 400? How much more? I currently have an Ampeg B2R which puts out 200w@8ohms and 350w@4 ohms. The 200 watts was definately not enough with just the 1x15 which is why I added the 2x10. (Also to fill out the sound.) But I've some cash and I'm thinking of going pre-amp/poweramp and so thought I'd get the experts opinion here... Thanks.