Hello Ray, and welcome to thecarversite.com Glad you found us!
I can't answer your questions, but I'm sure more information about your sub would help. Does it have L/R inputs and outputs, does it have its own power amp, make/model, that sort of thing.
I've never owned a Carver Receiver, and I'd never seen one until last week. I have Carver preamps, and I hook the powered subs I have up to the second set of outputs. If your sub isn't powered, that should work for you. If your sub is powered, I don't know if that's wise or not.
I'm not much help, and hopefully someone who's more experienced with Carver Receivers will have the answers you seek.