120V to 220V Converter Stabilizer or not?

I just purchased a pair of Raysonic monoblocks without knowing they were 220V and then I bought a pair of AR1500W Voltage Converter Stabilizers. One was clicking real bad and I had to unplug it. The other one clicks a few times at random every hour. I am trying to return them but I am not hopeful. Now I see there are relay and servo voltage stabilizers and I have the relay stabilizer. I don't want to listen to relays clicking constantly.

Did anybody here unplug the stabilizer and use just the voltage step-up transformer sucessfully? I can't find a schematic of the transformer or the stabilizer, but I did find a schematic of an AVS stabilizer wth a relay in it.

With a tube amp how bad would 1:2 step-up of AC voltage fluctuations be?

Is a 220V surge protector ever used with step-up transformers?

In another thread someone said they used a Variac. What kind of Variac?