Re: Advice on transformer hum Reply #50 – 2018-01-15 10:46:51 Think we might be getting a bit sidetracked. The problem is with a DAC, not an amp. I do indeed have a Classe amp, which does emit some mechanical hum, though that is not a particular problem as it is quiet enough to be inaudible from the listening spot. The DAC hum however is audible and I am still trying to fix this issue.Further to some of the posts above - I tested the voltage at my house yesterday - and the multimeter was reading 245 and 246V. So I would have thought that the voltage level is OK at least?