Nice tube talk in this article:
http://www.6moons.com/industryfeatures/btb/1.htmlexcept:
Okay, but you inventory much which would seem of interest to the high-end valve lover. So what’s up with the NOS trend? I mean, really, isn’t it mostly retro? Telefunken simply looks cooler than Sovtek stamped on the glass? Or are there bona fide advantages of quality and sound? Are we really to believe that valve quality and production processes have devolved over time?
Upper right: Not for sale. BTB's oldest valve dates back to the 1920s.
The explanation is simple. In the 60s when valves enjoyed their halcyon days, the average German income was about 500 Deutsch Marks and an EL34 of the era sold for 15DM. If you transfer that relationship to 2012, an EL34 still sells for about €15 whilst the average income has come up to €3.000/month. It’s easy to see that tubes today are far more affordable. Hence the inverse is true too – price pressures on manufacturers are much higher today. Because valve production remains about 90% manual, you can’t compensate with automatization. In the past selection was much tighter and rejection ratios were far more generous. Today things make it to market which would have been trashed then. That’s why the quality of vintage valves tends to be quite high to make NOS much more than just a fascination with retro.
