I bought it on ebay from some surplus store. It was a few years back and I don't have the emails anymore. You should watch for isolation transformers on ebay, craigslist or similar websites. You want a 220 to dual 110 transformer and you will wire it use it on 110V as primary then you tie the center of the two secondaries together and get balanced 110 on the output. Look for one rated at at least 5kVA with electrostatic shield. If I come across something on ebay I'll send you a link so that you have an idea what to look for.