I got thinking the other day after reading an article that used a capicitor to power a small audio project, would it work to use 2 large value capacitors in series with the + terminal on one cap going to supply + (12 v) the - terminal of this cap connected to the + terminal of the other cap and the - terminal on cap #2 going to ground?, therefore providing a center tapped 12 volt supply (actually +6 and -6 v with a common ground), it works with 9 volt batteries to provide +9v and -9v with a common "ground". I don't have any large caps to try this myself.