Not entirely sure what “ear training” is, but I think that in the context of audio hi-fi, my advice would be to take time to listen. Really listen to the music.

I am in the process of rebuilding my 30-year-old (musical fidelity, sonus faber) system. Part of my equation is to avoid made in China, or any other country with poor human rights. It’s a principle.

There is still plenty of fab hi-fi made in the UK, and perhaps other, more enlightened countries. If companies don’t boast where they manufacture, then it’s probably not what you want to hear!