Another vote for using a transformer. Be careful on Amazon, as there are a lot of junk products that do not carry any safety certifications.
I have been happy using Krieger brand products. They are UL and CSA certified, and utilize toroidal transformers for lower noise. They come in a number of sizes. Here is an example:
https://www.amazon.com/dp/B00HDUUL40?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
I would go for at least double your amp's power usage (not rated output power).