Carvin SX-15 Preamp

Hi everybody,
I am attempting to build a bass amp head utilizing a Carvin SX-15 Preamp and a DBX 1 Compressor/Limiter 262. I am looking at a 210 watt per channel (420 watt Bridged) power amp board. Typical bridged configurations only use one of the input channels. I want to retain use of both channels while in mono but I am concerned about combining right and left outputs from the SX-15 using a common ground. Will this damage the preamp? I would also like to maintain the versatility of switching between stereo and mono. Anybody have any input?