NFB cap instead of resistor? Anyone familiar...

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by ontariomaximus, Apr 24, 2008.

  1. ontariomaximus

    ontariomaximus Member

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  2. Dr. Fried

    Dr. Fried Member

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    It looks to me like it's acting as a high-pass filter to feed back only high frequencies, in effect reducing those frequencies (due to the NFB). The amount of attentuation would be governed by the negative gain. In my SE designs I use a larger-value cap (.022-.10) in series with a FB resistor to shape the bass response according to the speaker I'm using.
     
  3. ontariomaximus

    ontariomaximus Member

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    If the output transformer only had an 8 ohm tap, would I scale the cap up to approx 1000pf (.001)?
     
  4. Dr. Fried

    Dr. Fried Member

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    That would be a good place to start, but I would tweak that value by ear - small caps are cheap!
     

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