Mamboberry HD DAC+ v2 - constant noise

[powskii]

Hi,

Thank you for this precision. By the way thanks for this great work on moOde.

I've just tested with a new Pi 3B+ : same problem on both DAC : constant noise/hum with software volume controller.
Disabled vol controller are OK on Hifiberry and Mamboberry, hardware vol controller is ok on Hifiberry.
So not a Pi problem.
This hum appears only when playing audio from USB , webradios are fine : why is this please ?

Regards,
Xavier