Measuring Amplifier Output Impedance?

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by takato14, Feb 10, 2016.

  1. takato14

    takato14 God of Ruin

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    Is there any simple way to measure the output impedance of an amplifier?
     
  2. T.Rainman

    T.Rainman Acquaintance

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    yes,

    put a 1kHz tone on it, measure the output voltage without a load, then apply a low R load (say 10 Ohm) and measure the voltage again.
    The ratio between the voltage without a load - loaded voltage and the voltage across the load is the same ratio as the known load and output R.
    Make sure the test voltage is low (say 0.1V) to avoid current limiting which will skew the results.

    You can also use a 100 Ohm load resistor but the outcome will be less accurate when the output R is low.
     
  3. ultrabike

    ultrabike Measurbator - Admin

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  4. takato14

    takato14 God of Ruin

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    Thanks ultrabike! Very helpful.
     
  5. numbercube

    numbercube Acquaintance

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    If you use a cheap multimieter, better play a 50 or 60 Hz tone.
     
  6. takato14

    takato14 God of Ruin

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    would any adjustments to the formula be required in this case?
     
    Last edited: Feb 13, 2016
  7. numbercube

    numbercube Acquaintance

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    no, same formula.
     

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