Originally I had said that a goal was to be able to use a 12v wall wart with a single controller board to get a 1.7-10v variable output. Today I confirmed that this use case is not possible. You require a dual supply for the regulator board to work (although the negative side requires very little current, so you may be able to get by with a charge pump or something to supply the current). I apologize for the inconvenience; however you can get a couple of cheap switch mode supply for not a lot of money these days so there is really no reason not to go this route. (For instance, I purchased 2x 15v 7A supplies from Mouser for less than $25 CAD each. You can buy similar supplies on eBay for under $10, if you are willing to risk the fire hazard. I have heard that you can link two wall warts to get a balanced supply, but am not sure if this is safe or not, so don't try it without doing your own research.)