Tube amp sound isn't all down to the tubes. Transformers play at least as large a role. And as with everything else not just the specs but the wire and even the way the wire is wound matters. Cheap tube amps tend to use stock transformers that measure a lot better than they sound. Also if you look inside the good stuff you will see quality connections, highly organized layout, and lots of great big name brand caps. That alone can tell you a lot about your amp.
With tubes, yes there are differences between brands but generally minor compared to differences between tubes. So if you really want to get some experience what you might want to do is look for an amp that can run on different tubes. My old Aronov for example could run on 6550's or KT88's.
Personally though I would skip the cheap stuff and focus on finding the one that draws you into the music, gets your foot tapping, skin tingling and eyes watering. But that's just me.
With tubes, yes there are differences between brands but generally minor compared to differences between tubes. So if you really want to get some experience what you might want to do is look for an amp that can run on different tubes. My old Aronov for example could run on 6550's or KT88's.
Personally though I would skip the cheap stuff and focus on finding the one that draws you into the music, gets your foot tapping, skin tingling and eyes watering. But that's just me.