What about measuring the damping factor of a power amplifier with "traditional" instruments?
I've tried with a precision AC voltmeter, an oscilloscope and a frequency generator, comparing the output voltage into two different loads (10 ohm and 0.68 ohm resistors), hence I could extrapolate the output resistance of the amp, and so the damping factor.
I made this at low levels, far from saturation limits, and at 1KHz.
Is this correct?
There is a better technique?
Thanks
Tortello
I've tried with a precision AC voltmeter, an oscilloscope and a frequency generator, comparing the output voltage into two different loads (10 ohm and 0.68 ohm resistors), hence I could extrapolate the output resistance of the amp, and so the damping factor.
I made this at low levels, far from saturation limits, and at 1KHz.
Is this correct?
There is a better technique?
Thanks
Tortello
Damping factor is kind of a worthless specification.To a large extent so is output impedance.It sounds like you are measuring it properly.What does it gain you? The more feedback the design has the bigger the number is.When the amp clips no feedback is available to produce those nice numbers anyway.I own several McIntosh solid state amps with single digit damping facors.After adding bypass caps to various areas of the circuit they sound 'tighter' and have more 'punch' and 'slam' than direct coupled amps with damping facors that measure in the hundreds.The motional impedance of a loudspeaker is usually less than 1 ohm.The DC resistance of the voice coil is in series with the crossover network and speaker wire.This always swamps Rg, the output impedance of the amplifier.
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