Are they cheaper than 240 volt power supplies + a step down transformer?
I got these together with my miner when purchased. Never considered it to be a problem until now.
Now I will definitely either look into industrial grade transformers or get 240v power supplies like you suggested
very strange,did you buy your miners from an oficial suplier or second hand?
if I'm not mistaken,no site is selling 110v power supplies with the miners
also you should be better off buying a 240v supply instead,if you ever deicde to buy additional miners
you will get a 240v from the get go and don't have any troubles with transformers and converters