I've used a vintage Japanese 100V Luxman MQ-70 tube amp with a step up transformer from AcuPWR (quality US made transformers) with good results. Many people frown upon using transformers as they can increase the noise floor, and they generally decrease the value of high quality aftermarket power cords since the power then needs to go through the transformer. But depending on your expectations, you can still get good results.
One thing to note is that gray market equipment is not always serviceable by Luxman in the United States, so always take caution/consideration in your purchase.