The AM3 has utilized the OPA1622 from Texas Instruments.
The OPA1622 is the newest addition to the Ti Burr-Brown product line, in order to achieve full balanced output, there are a total of six OPA1622 chips installed. This enables both TRRS 2.5mm 4-pole and unbalanced 3.5mm output with an ultra-low output of THD at 119-dB.
Raise the performance bar yet again with the AM3 - 2.5mm balanced earphones or headphones are required.
Output Power 420mW into 16-ohms 540mW into 32-ohms 70mW into 300-ohms