I've been using my Sunn PB-10 preamp into a Sunn concert slave head to push two ampeg svt 610 cabinets. Each cab is 4 ohms for a total of 2 ohms. The rig sounds great but since I was unsure of the ability of the head to handle a 2ohm load, I upgraded to a sunn coliseum slave which is known for its 2ohm capability. Problem: despite the lower wattage, the concert slave sounded better. I also ran a Crown 1000xls and still prefer the souns of the Concert Slave. If the concert cannot handle the load, I'd consider getting a second identical one for a dual concert slave setup so each is running at 4ohms. The head sounds great with a single cab as well. My question: can the concert slave reliable handle 2ohms? Second question: anyone into doing a straight trade 70's black knob coliseum slave or Crown 1000xls for 80's red knob concert slave?