I need 36VAC, I've found 12VAC, 18VAC and 24VAC. I think I can combine a few of these to get my 36VAC (18 + 18 or 24 + 12 = 36) Can I stack (combine) a couple of VAC transformers to get the voltage I want, or will this give me unpredictable / unuseable AC outputs. I need an output of 36VAC to supply a circuit that I purchased.