• Re: Line Level Filter w/Tfr Input Help? - KevinC 16:31:57 06/21/04 (3)
  In Reply to: Line Level Filter w/Tfr Input Help? posted by SteveBrown on June 21, 2004 at 11:54:19:

  I think that it is a good idea to use a resistor from each grid to ground in the secondary of the LL1676 to define the input impedance for the prior stage and to aid the transformer by providing a tube-invariant termination. This also allows you a straightforward calculation for your high pass filter.
  
  
  

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  • Re: Line Level Filter w/Tfr Input Help? - SteveBrown 08:06:49 06/22/04 (2)
    In Reply to: Re: Line Level Filter w/Tfr Input Help? posted by KevinC on June 21, 2004 at 16:31:57:

    Thanks Kevin. So if I put say, a 100K from each grid to ground, then I would use 100K as the input figure, or would it be 100k || 100k = 50k? Thanks!
    
    

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    • Re: Line Level Filter w/Tfr Input Help? - KevinC 08:11:00 06/22/04 (1)
      In Reply to: Re: Line Level Filter w/Tfr Input Help? posted by SteveBrown on June 22, 2004 at 08:06:49:

      If the LL1676 is wired 2:1+1, then the overall turns ratio is unity, so the input impedance with two series connected ( grid-to-grid) 100K resistors is 200K. However, I would be inclined to use 2 x 50K, because lower resistance terminates the transformer better.
      
      
      

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      • Re: Line Level Filter w/Tfr Input Help? - SteveBrown 09:10:41 06/22/04 (0)
        In Reply to: Re: Line Level Filter w/Tfr Input Help? posted by KevinC on June 22, 2004 at 08:11:00:

        Thanks!
        
        

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