If I were lucky enough to be in your shoes I would look for a locally built tube amplifier. Japan has been the heart of low power amps. Speaking for myself I would avoid the big brands that build a ton of amps, spend a ton on marketing and advertising and look for an artist. There are some " listening bars " there where people have a drink and just listen to music. I think if you look on youtube and type that in you will find what I am talking about. Those cafe owners are true music lovers and should know a lot about what is available. Here are a couple here.
https://www.youtube.com/watch?v=eQXQAYdncbM
https://www.youtube.com/watch?v=e8yQFCU-rbM
https://www.youtube.com/watch?v=eQXQAYdncbM
https://www.youtube.com/watch?v=e8yQFCU-rbM