Don't worry about 50 year old ears. You may not be able to hear the dog whistle frequencies, but you can still judge what is good or not. Maybe even better now.
I noticed my eyes starting to go soft at about 40. Now I need reading glasses, but I can still tell a babe from a dog, no problem.

Think about a budget for your tube amps. When you come up with a number, float it here. You'll get plenty of suggestions. A nice tuber amp will really help these sing.