My amps have no audible hum with my ear up against the speakers.
I’m glad to hear that.
All tube amps don’t have hum problems, and all solid state amps are not hum free.
I would agree with you. All of the tube amps I’ve ever owned, did (have a certain amount of hum). I prefer my noise floors to be in the -95 dBu area (exceptions being vinyl playback). With that in mind, I could never find a tube amp that approached that. I’m not saying they’re not out there, I just however gave up my quest trying to find one. When it comes to tube headphone amps, I also don’t like the fact that rarely have I ever heard one that sums to mono, correctly (like SS does) 100%. This matters when listening to any audio mix, as the mixing engineer many times will pan certain sources to center (mono). Many wouldn’t notice this, or care about it, but I do.