So I just acquired an older Ampeg SVT810 classic cab. it's pretty run down, needs new rails and rubber feet,and could use a new tolex job. The jack plate only has 2 1/4 inputs. all the writing has been rubbed off. I'm not sure which input to plug into or which input does what. With the cab I got a 79' Ampeg V-4B head. It has 2 1/4 outputs, and can has a selector switch to run the head at 8, 4, or 2 ohms.