Hi, Coyotex83.
Firstly thanks for your sharing the test result about your AM3 with us.
Kindly be noted that, the IC used on the module AM3 more easily gets EMI interference from wireless devices,such as the router or your phone. But based on the advantage brought by the OPA1611, we can not find other chip to replace it temporarily. Because it will influence the whole sound style. Therefore, we decide to keep using OPA1611 for the AM3.
Actully, we already took some mensure to improve the interference noise. And now, the noise level drops to about 10uV.
Ok, we have to admit that, the noise level on the AM2 is lower, and about 6uV. However, pls be noted that, the ouptut level of the AM3 is about 4.5V, which is higher than AM2( about 3.1V). It is not easy to get the low noise level when the ouptut level is comparatively high.
Anyway, we will also keep making more tests, and hope find a better way to lower the interference noise on the AM3 further.
If there is any feedback, pls let us know.