Bench testing amplifier

Yes, you can do this- no need to pull it from the car.  You can just use a cd with test tones.  As long as you know the ohm load presented to the amplifier, you can solve for watts.  Power (in watts) = ac voltage^2 / ohm load.My ex once told me I have a perfect face for radio.

This method does not actually tell you "how many watts rms the amp puts out."  It will give you a very gross average power number at the frequency used for the test signal, and at a fixed resistance or open loop.  It's a useful method to help set gain properly.  If you really want to test your amp's true output, you'll need a lot more gear than a multimeter.  You'll need dummy loads, a function generator, a regulated power supply, an oscilloscope to monitor for distortion and clipping, and experience or help.  Support the12volt.com