How to measure an amplifier

[RayDunzl]

What equipment do you need to measure the performance of an amp?

When I want to guess power output during music, I put a scope on the speaker terminals, observe the voltage swings, and use Ohm's Law and a guesstimate of impedance to calculate watts.

To measure/estimate small signal (a few volts) amplifier performance I have a Focusrite USB interface and feed its observations to REW.

Also what are the pertinent measurements to make?

With the data input to REW I can see frequency response, impulse response, phase, step, distortion, noise...

https://www.audiosciencereview.com/forum/index.php?threads/krell-fpb-350-mcx.9870/#post-268131


Oh, and you need something with which to generate a signal, so I send a test tone frpm REW to my DAC, which I expect has rather insignicant problems of its own relative to the power amplifier.

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The quality of the above is enough to satisfy curiosity, but maybe not provide definitive information.

 

[Razorhelm]

@Blumlein 88 As far as I'm concerned everyone has been really helpful, it was just that first reply which felt very dismissive. He has stated it was not meant to be rude and I'm happy to accept that and get on with learning.

I'm putting it down to lack of tone on the internet and moving on