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Linux/PCM2900C: Problem with capture Volume

Part Number: PCM2900C
Other Parts Discussed in Thread: PCM2912A

Tool/software: Linux

Hi everybody,

I'm using an USB audio board with PCM2900C, in a Linux system. The chip works great, but it's not possible to adjust the capture volume in the alsamixer configuration panel. Is it a problem related to chip configuration or is it a limitation of the chip?

  • Hi, Antonino,

    Thanks for your post.   This device has an internal volume change block for each channel that can be updated per host system request. However,  master volume  control is not supported. Any master volume change request from the host system will be ignored by the PCM2900C.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • Hi Diego,

    thank you for your reply. So there is no way to change the volume of the ADC? Is there another chip that support this feature?

    Best regards

    Antonino Catena

  • Hi, Antonino,

    The volume for each channels could be modified, but unfortunately master volume can't be modified. The PCM2912A has the option to modify master volume.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • Hi Diego,
    thanks for your support.
    Handling the channels volume individually would have been definitely fine.
    After your suggestion I've noticed that amixer exposes a number of channels,
    this one:
    Simple mixer control 'Capture',0
    Capabilities: cvolume cswitch
    Capture channels: Front Left - Front Right
    Limits: Capture 0 - 63
    Front Left: Capture 63 [100%] [30.00dB] [on]
    Front Right: Capture 63 [100%] [30.00dB] [on]
    acts on both channels, behaving like a master volume control.