Measurements on their own are no good unless they can be seen in relation to something. Having established the measurements baseline, I want to get an idea on how the preferred OPA2134 performs.
The conditions are the same as they were with the baseline setup, and the op amp is placed in a test rig without any filter circuitry. The gain is 1.36 dB.
The OPA2134 shows a THD of -118.6 dB / 0.00012%, which is the same as I got on the loopback test. Notice that a lot of the noise below 1 kHz has vanished. This must be because of the OPA2134's noise rejection.
This is obviously beyond what the QA401 can measure, and Texas Instruments claims that the OPA2134 has a THD of 0.00008%. It does show what the audio analyzer is capable of, which is very useful for the next measurements.