EF86 NOS tubes and varying plate currents - tested as new
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[quote author="PRR"]> Generally I would not trust any tester that is an Emission-only tester.
Do NOT emission-test tubes recklessly. It is a strain on the cathode. It is not as bad as testing car batteries by throwing a wrench across the lugs and eyeballing the size of the spark, and most of the cathode thorium will come back after some hours of normal (non-tester) use, but still tube-abuse. [/quote]
So is a test for mutual conductance as much of a strain on a tube, or just emmission testing. After doing some reading I see that some of the (non ebay) dealers that sell real NOS (plastic wrapped) and tested NOS (opened) actually test their tubes for output it gm, plate current or both. A NOS should have output of 1200-1400gm according to the data I found. Incidentally, tubes with 1200gm output also had a plate current of about 6.7ma. I'm not sure one correlates directly to the other, it's just what i noticed.
Unfortunately most of the user opinions I read about the modern (current made) tubes are riddled with bad experiences. Do they just make the things and put them in boxes and let buyers do the QC?
I read about the old Mullard factory coming back online. Maybe that will turn out good for us.
Anyone have a link to data about where each brand is made? (I know some brands are actually made by others, etc.)
Do NOT emission-test tubes recklessly. It is a strain on the cathode. It is not as bad as testing car batteries by throwing a wrench across the lugs and eyeballing the size of the spark, and most of the cathode thorium will come back after some hours of normal (non-tester) use, but still tube-abuse. [/quote]
So is a test for mutual conductance as much of a strain on a tube, or just emmission testing. After doing some reading I see that some of the (non ebay) dealers that sell real NOS (plastic wrapped) and tested NOS (opened) actually test their tubes for output it gm, plate current or both. A NOS should have output of 1200-1400gm according to the data I found. Incidentally, tubes with 1200gm output also had a plate current of about 6.7ma. I'm not sure one correlates directly to the other, it's just what i noticed.
Unfortunately most of the user opinions I read about the modern (current made) tubes are riddled with bad experiences. Do they just make the things and put them in boxes and let buyers do the QC?
I read about the old Mullard factory coming back online. Maybe that will turn out good for us.
Anyone have a link to data about where each brand is made? (I know some brands are actually made by others, etc.)
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