I am planning on buying a bass preamp and a power amp. I want to run the power amp in bridged mode. I will be buying 2 4x10" cabs. If I buy 8 ohm cabs and run them both with the amp in bridged mode does that run at 4 ohms? Likewise if I buy 4 ohm cabs, will that run the amp at 2 ohms (which most will not do)? Thanks!