Why are older tubes so much sought after

Larryi,

I would agree with you. Manufacturers need a constant supply of reliable tubes that can be bought in bulk for a reasonable price.

I guess it is up to the individual to search and test which selection of tubes works best in whatever equipment. Though this can be tedious. I spent a lot of time and money trying out valves that were unsatisfactory. Though I felt good when I finally found the best combination.

I doubt very much that a good quality valve cannot be made today. Manufacturing techniques are far more advanced now. Unfortunately we are such a small market to cater for that it probably isnt worth tooling up for these days. Even so, we still run into the problem of which ones to remanufacture? Imagine remaking the bad sounding ones!

As someone said the laws of physics have not changed (yet! Maybe CERN will change this) so in theory performance can be copied or even bettered. Who knows? We live in the age of information. Everything we need is out there somewhere.

Wouldnt it be great if the equipment just worked at its finest performance level, rather than us wasting time listening to tubes. We could be listening to music or dealing with things of real importance like which cable sounds best? Aaagggg!

The same economic issues hold for other components as well. There are tube gear manufacturers who know how to make a better output transformer but cannot make them like they used to. That is because, with the scale of production so much smaller than it once was for transformers, the manufacturer cannot order the needed specialty steel in a large enough batch.

Larryi,
sadly its a sign that this technology has become a bit of a dinosaur with only the select few interested. Although I see a few tube docking stations for ipods!

I know many here will disagree here, but in my experience other technologies, especially in power amplifiers, have moved so far ahead in terms of what you get for your money vs performance, and without the insecurities of knowing whether you have the best tubes from the 1950s or not.

The small magical details that we obsess over like this tube or that NOS tube bringing out extra detail here or there, can be had at the flick of a button on a remote control now without even reaching for a screw driver.

I have been trying out some of these latest generation of digital and switching amps for a while now. Some amps have room correction and a host of toys built in. The various filter settings are very powerful and have similar effects to tube rolling.

http://www.mullardtubes.com/Video.aspx

personally, ive tested A/B old NOS tubes 12au7 12at7, from GE and others vs. the new sovtek 12ax7a, and the new sovteks sound better to me.

analized the harmonics and noise floor with izotope ozone, and mda vst free plugins. with sine tone at arround 50hz.
the new sovtek ax7a has lots more harmonics, than au7 and at7.

it all depends of you like color sound or grey sound.
i like color, anyway.

Juanpablocuervo,

I have had the same experience with 12au7.

Fantastic film. I have not seen that one before. Notice all the internal parts are selected and moved by hand, and not a rubber glove to be seen. All the salt from sweaty hands carefully preserved inside.

I will go for new valves I think...