From: ruffrecords@yahoo.com   
      
   Don Pearce wrote:   
   > On Sun, 26 Sep 2010 10:36:07 +0100, Ian Bell   
   > wrote:   
   >   
   >> I would be surprised if it were a Miller effect but I will do the   
   experiment you suggest and let you   
   >> know the results.   
   >   
   > If it is Miller it will be strongly frequency dependent. That should   
   > be easy to check.   
   >   
   > d   
      
      
   Looks like there is some frequency dependent. I made additional tests at   
   100Hz, 500Hz and 4KHz as   
   follows (grid distortion in original circuit):   
      
   100Hz   2H -63dB, 3H -65dB   
   500Hz   2H -58dB, 3H -61dB   
   2KHz    2H -49dB, 3H -62dB   
   4KHz    2H -46dB, 3H -65dB   
      
   Looks to me like the second harmonic rises with frequency but the third varies   
   little so I would   
   guess the 2H is coupled somehow from the plate and the 3H is probably the   
   onset of real grid current   
   distortion.   
      
   It might be interesting to repeat this with a grounded grid configuration.   
      
   Cheers   
      
   Ian   
      
   --- SoupGate-Win32 v1.05   
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