I was told that the differences may be due to the upgrades in both sources and speakers. Vintage gear was not being fed by high end sources which reproduce much more of the audio spectrum accurately. The speakers many of us are using make a huge difference too. Compare the average speaker today to most of the speakers made in the 60's. We are demanding 20hz to 20khz response as a minimum. Try to get that out of an old pair of Bozaks? The designs had to change/improve.
That old "tubey" sound was due to us listening mainly to really nice warm midrange and not much more.
That old "tubey" sound was due to us listening mainly to really nice warm midrange and not much more.