OK I CHANGED MY SETUP. NOW I AM RUNNING BOTH SUNN 1X18 CABS SIDE BY SIDE ON THE FLOOR WITH A SUNN 2X15 CAB SIDEWAYS ON TOP. I RUN BOTH 1X18 WITH THE COLISEUM 880, AND A COUPLE MONTHS AGO PICKED UP A COLISEUM SLAVE, SO THAT IS WHAT I POWER THE 2X15 WITH OUT OF THE PREAMP OUT OF THE 880.