I did that to make a 90V supply for a grain moisture meter. I have a lot of 220-12 1W transformers, so wired one to give 12VAC, and wired 2 with the 12V in series and the 220 in parallel to give me 110VAC ( actually with losses more like 90VAC) which was rectified and then dropped to 90V with a high voltage transistor ( MPSA42) and a stacked pair of 47V zeners. the filament supply was made from the 12V supply via a LM317 regulator to give 1V2 for heating ( 60mA filament hearing aid valve). Worked very well, and was cheaper than buying 10 PM3 batteries every 6 months.