rewinding a transformer from 120V 60Hz to 220V 50Hz, if not done properly and calculated carefully, can result in a transformer heating and humming without any load, what could be your case. So, to me , 1st suspect is the re-winding work. Try the transformer alone, disconnected from the amp, just the primary to the 220V line. If it heats up, the winding is wrong.
I know this because we have 220V here, and I've done those conversions several times, with 2 different techs teaching me about the 50-60Hz issue, and trial-error in some cases, trying different wire diameter and number of turns in a simulation software, until find a transformer that match the Ampere, Watt, Voltage and Physical size of the original.