When were the best tube amps made?

Someone above made a Harley Davidson reference, and it fits well in this discussion. The best tube amps that ever existed are being made today, but they still include the same important electrical physics element, inherent distortion. Currently Harley has to be careful not to engineer out the trademark sound of the past engines just like the makers of tube amps want to make all parts of the amps better with what engineers have learned, but still using the tube design factor. Tube amps are very highly refined today with better transformers and more capability than ever, but just the fact that they are tube amps, and will have ~.5% distortion to start, and this distortion seems to add a harmonic that is pleasing to human ears still makes them desirable and makes the current offerings from all over the cost spectrum alluring to audio lovers. I have no way to state to anyone what the best amp from past or present might be, but I can admit that I'm still interested in a MC275, and even some of the offerings from lower end players such as Monoprice and similar to play with. While I look at some vintage pieces with nostalgia and desire, knowledge and common sense tells me to buy something current with all the improvements.

@dynamiclinearity 

thanks for thee superb explanation. May explain why i love solid state. 

@atmasphere 

what are the tubes nowadays like? I keep getting the impression that NOS are the best

what are the tubes nowadays like? I keep getting the impression that NOS are the best

@lohanimal That depends on the tube. I think most of the NOS tubes are better than a lot of the new pentode power tubes.... but there are some excellent 6SN7s being made these days that our customers say are better than 'the best' NOS... And there are some very decent pentode power tubes too- so the best answer is 'it depends'.

@atmasphere 

Tis ever thus...

I keep flirting with the idea of getting a valve integrated for my nearfield set up which has 4 ohm monitors. My current integrated is superb.

I am odd coz i love integrateds

Since I've gotten mentioned in these discussions I'll cite a few good tube examples.

CAT has a superb reputation and I've heard this from other tube designers I know and respect.

David Berning is a genius. His ZTOL circuit is one of the few real amp inventions in decades and his amps are special.

And I'm biased(pun intended, since the designers were good pals) towards the now, defunct Melos amps. Tube monoblocks with over 400 wats in triode and 25 watts class A and a damping factor 0f 20 from tubes, all from just 4 output tubes is something special. And the 400 watt rating is one pulled back from higher ratings for reliability.

And I know I'm missing at least a few other good tube amps.