When were the best tube amps made?

Like asking who was the best fiddler. Paganini not eligible.

Modern state-of-the-art tube amps continue to evolve and push the envelope ever farther, so the best tube amps ever made are likely on a test bench right now.  The Convergent Audio Technology Statement Extreme comes to mind.   

@knotscott  No argument with CAT!!

There are other aspects to this question. IMHO value must certainly enter the equation. All amplifiers are compromises on some dimension. Either with respect to size, weight, convenience, aesthetic considerations, system synergy.

Nowadays there are many very fine builders who have studied the history of this field and are now seeking out the best components they can find.

Synergy with the desired speakers is also important. In my system, with my 94dB efficient speakers, 1.5 watt amplifiers sound superb.

Guess my short answer is the best amplifiers are being made now.

After Audio Note kondo' s Ongaku.