From: peter2@hipson.net   
      
   On Fri, 03 Sep 2010 08:49:13 +0100, Richard  wrote:   
      
   >On 02/09/2010 23:14, François Yves Le Gal wrote:   
   >> On Wed, 01 Sep 2010 19:44:29 +0100, Richard  wrote:   
   >>   
   >>> What will an audiophile like to know so he can have a good idea what he   
   >>> or she would be buying? I want to describe the items so a buyer knows   
   >>> the state of the tubes.   
   >>   
   >> Full test :   
   >> Shorts (none whatsoever), gas, grid emission, leakage (at least 500K and   
   >> preferably more than 2M between all elements).   
   >> Transconductance and current (nominal is 11.5 mA/V and 140 mA @ 250V platye   
   >> and -15V grid), another set of measurements @500V, a must with big bottles.   
   >> End of life tests, same as above but with reduced heater voltage (6.3V   
   >> nominal, 5.5V or so for EOL), transconductance and current should be at   
   >> least 95% of nominal.   
   >>   
   >> Plus a full description. Add some nice hi rez pics showing the tubes as well   
   >> as close-ups of the getters.   
   >>   
   >   
   >These tubes have one getter, at the top.   
   >   
   >How metallic-looking should the getter flash be?   
      
   Very metallic. No whiteness at all (indicates leakage).   
      
   >Does the flashing start   
   >out metallic then get less metallic-looking?   
      
   It can, but that indicates a tube (valve) that is failing and is   
   likely gassy.   
      
   >   
   >Can you test for "softness"?   
      
   Better testers can.   
      
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