When were the best tube amps made?

@whart   I was a purist so my SP10 is the original.

It was said the microphony could be reduced by placing the amp between heavy steel or stone blocks but I have never tried.  I still listen to it occasionally today in my second system; Zarathustra TT (Simon Yorke S2, very rare), Zeta, Ortofon Anna, into the Krell KSA50 and Audiostatic ES200.  Very vintage, apart from the Anna.  I must say I don't hear microphony in the AR.

Most recognise SP10 as a classic and it still commands prices to match; was $4000 in the early 80s and nearly $3000 today.

McIntosh MC 30s. Ethereal sounding! Like nothing else. 

When people say that today's amplifiers are better, or vice versa, have they really heard a broad enough sampling of both to make that claim?  Have they really heard the best of vintage amplifiers--such as Western Electric 59A (252 pushpull), 91A (300B single-ended), 86 (pushpull 300B), Marantz 9, etc.?  I heard a demonstration where a very good current model Audio Note Kageki (parallel single-ended 2a3) was compared to the 59A playing Audio Note AN-E speakers.  The Kageki sounded wonderful until the 59A stepped into its place--the comparison was so startling that it made the Kageki sound like it was broken.  The Kageki is now almost a six figure amp and it does not come close to the 59A playing speakers that should be friendly to Audio Note amps.  I really like the sound of the Kageki (I own a pair), but the 59A is so much better--more vivid and alive, more rich and harmonically saturated, and still relaxed sounding (not edgy).  The 59A probably costs twice as much as the Kageki these days, but for someone who can afford it (not me), it would be the end-game amp.

Yes! It is ,and  we can NOT make such amplifier even in the future.

The time window has closed.

Best is a loaded term. What output power is required? What speakers being driven? What size room? What kind of music? Long term reliability? Etc.

I loved an old Mac I had from the 60’s, loved my Conrad Johnson Premier Four & now really enjoy my Rogers EFH 200 Mark II integrated amp which probably has the some of the highest build quality around & sounds excellent. 
 

To each his own.