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   From: flegal@domaine.tld.invalid   
      
   On Mon, 27 Sep 2010 14:15:34 -0700 (PDT), iodemus@hotmail.com wrote:   
      
   >DET5 was made by Marconi, and is a directly heated triode with balloon   
   >shape. It is said to be an equivalent of the British military NT40.   
   >NT40 is said to be equal to PX-25   
      
   According to my files DET5 = PX-25 = LK4200 = CV384   
      
   >except it is rated for 600 volts due to higher vacuum.   
      
   Higher vacuum has very little to do with plate ratings : a relatively low   
   vacuum pentode such as the EL34 was rated at Va = 800 V design center value;   
   the small 6V6GT was pulse rated at 1 200 V !   
      
   >The glass bulb is thick and weight almost 50% more than PX-25. On the   
   >glass is etched Made in Bohemia, which I assume means the glass work   
   >is made there as the Bohemians managed to obtain a higher vacuum.   
      
   The envelope could have been made in Bohemia (what is now the Czech   
   Republic), where the technical glass industry was one of the best before   
   WWII, but the tubes were assembled and tested in the UK.   
      
   --- SoupGate-Win32 v1.05   
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