From: a@b.com   
      
   flipper  wrote in   
   news:u3sgr51d7ptkedrg60ae3ip08be0utqciq@4ax.com:   
      
   > The only down side I see, off hand, is stressing cathode-heater   
   > insulation.   
      
      
   Cathode-heater ratings for 6SN7 or 6CG7 are 200V. You only need -120V at   
   most from the bias supply.   
      
   As far as the voltage rating on the grid of the output tubes, some like   
   the 6550 is 300V, Svetlana EL34 is -100V , Sylvania 6BQ5 is -100V, but many   
   don't specify a maximum negative DC grid volatge.   
      
   --- SoupGate-Win32 v1.05   
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