Measuring the Burson V6 Discrete Op Amps - Part 5: V6 Classic - ITU-R IMD

26.11.17 06:34 PM By skrodahl

Check out this post for test setup and limitations.

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%.

Burson V6 Classic - ITU-R IMD at 1.36 dB gain
Burson V6 Classic - ITU-R IMD at 1.36 dB gain

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.

QA401 - ITU-R IMD
QA401 - ITU-R IMD

The Burson V6 Classic loses out to the OPA2134 once again. The OPA2134 measures -121.0 dB / 0.000089%.

OPA2134 - ITU-R IMD, 1.36 dB gain
OPA2134 - ITU-R IMD, 1.36 dB gain