If I wanted to measure the gain that a power amplifier provides to a signal with a multimeter, do I simply do the following:
- Measure the input signal's voltage e.g. 1 Vrms
- Turn the amplifier up to full.
- Measure the output voltage of the amplifier e.g. 20Vrms
- Output / input = amount of gain that the amplifier provides.
Is it that simple, or do I need to add a resistor to the output which is a similar load to what a speaker would be and then measure the voltage drop across that resistor?
What if I wanted to determine the watts of the amp? Then would I need a resistor of a similar value to a speaker? Or would it be better to measure the resistance of the speaker with an ohmmeter, measure the amps output voltage and then I = V/R?