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I use a curve tracer to generate a family of curves sweeping anode voltage and stepping grid voltage at a typical amp plate z.
I have a girl do that by switching the tracer between tubes in a pre-heat unit with 12 sockets. The test is about .5 second, the longest time is plugging in a set of 12 tubes to be tested.
If someone was serious about tube testing, it would not be too hard to make automatic pin connections for production line speed testing. The locator center pin could be found fairly easily by a test jig which would then engage spring loaded contacts around the outer sides of the pins. Pre-heat however would be a delay. 2 such machines could test could test 10,000 a 24 hour shift. That is more than the production levels of all current manufacturers.
The advantage would be printed curves that pertain to that individual tube instead of publishing phony copies of curves from the 1959 RCA handbook. Designers and home builders would be saved the effort of plotting their own curve families when building a new design, and those who want really matched tubes in the operating conditions it is going to be used in.
But there is no incentive to improve QC and consistency, everything they make now gets sold. There are only 3 main manufacturers and none show any interest in improving either their product or informing the customers what they are really buying. If they tested more effectively it would mean more fail-outs that could not be sold so being better would, in their eyes, lose them money.
Customers talk a good game but never bother to check on what they buy, but generate bogus claims on forums about sounds that one brand has over another brand. Until they are call out on their bs they will still be the influencers driving sales. After seeing how companies have manipulated forums and user review sites with fake "user" posts to bash competitors and boost their own product, I except that is happening extensively on musician forums as well.
So it really comes down to a few companies happy to deceive and a mass of customers willingly eager to be deceived. Everyone should be happy now.
Regarding exporting, not interested in the hassle of export licenses and costs that if geared, couple be copied by anyone locally in countries that would have the automatic price advantage. I do not want to be in the tube business, it is a service I created to be able to get proper tubes for myself. I buy in minimum quantities(2,000) and that is as large as I would want to risk in capital. If it was some unique product that I had an exclusive on, that could not be under cut instantly by any company willing to put a little effort. It is a commodity and any one can by in bulk from the same producers.
Since it would be so easy to do, the reason no one does test tubes is because there is no need or desire. As it is, most tubes replaced are perfectly good. The first thing a user does when there is a problem with his amp is the only thing he can do: replace all the tubes. When someone brings me an amp, 80% of the time the customer has already replaced all the tubes hoping to fix it himself. It is hard to guess how many perfectly good 12AX7s are replaced by someone trying to fix a "not turning on" or "no sound" problem.
I have a girl do that by switching the tracer between tubes in a pre-heat unit with 12 sockets. The test is about .5 second, the longest time is plugging in a set of 12 tubes to be tested.
If someone was serious about tube testing, it would not be too hard to make automatic pin connections for production line speed testing. The locator center pin could be found fairly easily by a test jig which would then engage spring loaded contacts around the outer sides of the pins. Pre-heat however would be a delay. 2 such machines could test could test 10,000 a 24 hour shift. That is more than the production levels of all current manufacturers.
The advantage would be printed curves that pertain to that individual tube instead of publishing phony copies of curves from the 1959 RCA handbook. Designers and home builders would be saved the effort of plotting their own curve families when building a new design, and those who want really matched tubes in the operating conditions it is going to be used in.
But there is no incentive to improve QC and consistency, everything they make now gets sold. There are only 3 main manufacturers and none show any interest in improving either their product or informing the customers what they are really buying. If they tested more effectively it would mean more fail-outs that could not be sold so being better would, in their eyes, lose them money.
Customers talk a good game but never bother to check on what they buy, but generate bogus claims on forums about sounds that one brand has over another brand. Until they are call out on their bs they will still be the influencers driving sales. After seeing how companies have manipulated forums and user review sites with fake "user" posts to bash competitors and boost their own product, I except that is happening extensively on musician forums as well.
So it really comes down to a few companies happy to deceive and a mass of customers willingly eager to be deceived. Everyone should be happy now.
Regarding exporting, not interested in the hassle of export licenses and costs that if geared, couple be copied by anyone locally in countries that would have the automatic price advantage. I do not want to be in the tube business, it is a service I created to be able to get proper tubes for myself. I buy in minimum quantities(2,000) and that is as large as I would want to risk in capital. If it was some unique product that I had an exclusive on, that could not be under cut instantly by any company willing to put a little effort. It is a commodity and any one can by in bulk from the same producers.
Since it would be so easy to do, the reason no one does test tubes is because there is no need or desire. As it is, most tubes replaced are perfectly good. The first thing a user does when there is a problem with his amp is the only thing he can do: replace all the tubes. When someone brings me an amp, 80% of the time the customer has already replaced all the tubes hoping to fix it himself. It is hard to guess how many perfectly good 12AX7s are replaced by someone trying to fix a "not turning on" or "no sound" problem.
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