ITU-R IMD is one way to measure intermodulation distortion. I am feeding the circuit with two test tones at -6 dBV, which will sum to 0 dBV. The test tones at 19 kHz and 20 kHz will produce a modulated signal at 1 kHz. The difference between the test tone and the modulated signal is the ITU-R IMD.
The ITU-R IMD for Burson V6 Classic is -118.1 dB / 0.000124%.
How does it fare in comparison to the audio analyzer itself and, equally interesting, our OPA2134 reference IC op amp?
Well, the audio analyzer can measure down to -122.2 dB / 0.000078%, so the Burson measurements are well within the analyzer's capabilities.
The Burson V6 Classic loses out to the OPA2134 once again. The OPA2134 measures -121.0 dB / 0.000089%.