How can it be that some old recordings sound sublime?

Agree with all of the above. Great tube equipment with people who cared about the sound. There is something very transparent about many of these recordings both classical and jazz. Like the Nelson riddle Capitol recordings from the late 50s. Fritz Reiner bartok recording from the mid fifties. But there are also great recordings being made now. The most recent Justin beiber record "purpose" is very beautiful sounding and I have a several great orchestral recordings of current composers music that sound transparent and beautiful.