I'm using the transformer to step down voltage to 120V in two HiFi systems, a slight hum is audible through amp/speakers.
Remember USA is 60Hz, Ireland is 50, so Hz can be an issue with US products.
It was tripping the 20amp breaker too often, so I installed a new one, still trips from time to time?.......thats without a load on the transformer. I wish it had four 120V outlets......only has 2. My loads are light, not pulling many amps.
U.S. multi socket extension outlets do not work when stepping down with a transformer as the neutral leg of the transformer has 240V (I found out the hard way, I should have tested with my multimeter first)
Otherwise, the transformer is fine, price is good.
I had difficulty with the French websites address format, my address was all haywire, I took a chance with my eircode.