Why Can't Tubes Be Mass-Produced Cheaply?


I often read that old tubes manufactured from the 60's or earlier are collectible items and often much sought after, and new tubes are not as valuable. Reasons cited are that these older tubes are a rare species, and they often sound 'better' and hence the hefty price tag on them. I am puzzled as to how these older tubes are different from the new ones and why they are better-sounding. Why can't technology today produce tubes that are similiar in quality to those in the yesteryears, or even better them? After all vacuum tubes, electron tubes or valve tube(where they call it in Britain) are electronic components made up by plates and filament. What happens if these old tubes become extinct? Why are there still so many of these old tubes available for sale although it has been almost 4 decades since they were manufactured? I mean once these tubes have run out of life they will basically be disposed off.

Pardon my ignorance as I cannot seem to find any discussion on this matter elsewhere. Any opinions would be much appreciated.
ryder
I think that it is quite possible that small signal tubes that can compete with NOS tubes could be manufactured again. Tube gear is very popular again so there is plenty of profit to be made and with the design and testing technology available today it could happen. They would be different from vintage tubes just as a car made in the 50s is different from one made today, but both have their strong points.

On another point, a vintage tube does not have to be NOS to sound as good as a NOS tube. Many tubes sold as NOS probably are used. But if they are still in like new condition they can sound as good as tubes that haven't been used and can last as long. Nobody kept track of most tubes made in the 50s and 60s to document if they were ever used.

To get good ones you either need to buy them from a reputable dealer who tests them or take your chances buying on ebay (where there are both reputable sellers and crooks) and test them yourself. There are pros and cons to either strategy.
Look, I have both NOS and new current tubes in 12AX7s, 12AU7s, 12AT7s, EL34s, 6V6s and 6L6s from a variety of manufacturers, both USA made and Europe that I run in both audio amps and CD players (Rogue, CJ, Jolida) and guitar amps (by Fender, Mesa, Divided by 13) and I honestly believe that the tubes made now are as good if not better than ANY used or new NOS tube I have in my collection. The new JJs are excellent tubes as are those by Electro Harmonix. I have no experience in the 300B single ended world so cannot comment there.

My senses and experiences tell me that there is much mumbo jumbo in NOS and I honestly believe this to be a unneccesary waste of good money.

The one NOS I will say IS as good as any out there are a couple of Telefunken smooth plate 12ax7s I have. They are very good but not that much better than the current JJ, Ei or TungSol.
I just worked with one dealer who will not sell anything other than new Electro Harmonix tubes for use in a few preamps that are "demanding" of 6922 tubes placed in critical positions where low noise and reliability are important, along with at least a touch of musicality. Of course I will also be trying a pair of Amperex PQ white labels I have around here.
Stevecham,

What I said in my post is:

When comparing small signal tubes such as 12AX7, 12AT7 and (especially) 6922, the modern versions from Sovtek and others are nowhere close if the comparison is made in a critical position.

By critical position, I'm referring to small signal tubes in EAR 834, Aesthetix Io and Callisto, Audio Research Ref 2, input circuit (12AT7) of VTL 450, 750 and 1250 to name but a few.

If you doubt me, do an experiment by putting new production tubes in the first stage of an Aesthetix Io and to make things fun, go with a .2 MV cartridge such as a Koetsu Jade.

If you can get new production tube to work as well as Telefunken, you need to reveal your magical source. I have a lot of people, including several manufacturers that would like to buy some of these tubes.
Some of the difference in opinion on whether NOS sound better than current production can be differences in hearing. As I get older I am less and less able to tolerate harshness or grain or glare. Speakers and gear that I once enjoyed now grate on my ears.

So my guess is that people who think that current production tubes sound great are better able to tolerate whatever distortion it is that hurts my ears. And that's not a bad thing, it saves you a lot of money, but your opinion may change over time.