The 220v - 110v step down transformers your tax dollars bought me have an audible 50Hz hum coming from the transformer and it’s driving me crazy. 
I’d like to source an alternative low-wattage (under 200) unit that will be dead silent for my listening room, but I’d like to know for sure it’s silent before I ship it all the way to Moldova and plug it in. 
Any d-_-b recommendations?

All transformers hum. The less they are taxed, the less audible it is. So oversized is your best bet.

I would perhaps see what Torus Audio can do here. Regardless, find someone that uses the Plitron LO-NO transformers - I imagine there is a step-down version.

Helpful information, gentlemen, thanks. 
 

I’ve not found any lono transformers with the right windings yet, but I did find a 500W Plitron step down converter that handles 220v-110v here: https://m.aliexpress.com/item/32979526968.html?spm=a2g0n.productlist.0.0.58bb3e80yKcyh9

I’m always leery of Aliexpress, but does that look genuine to you?

For $75? Very doubtful. The transformer alone would be more than that. And the one you linked is 100VA, not 500.

Edited September 3, 20205 yr by Pars

If you know what you're doing, then any 1:2/2:1 trafo will do the trick. Just need to keep in mind the HF and current rating.