[LAU] USB cassette player only recognized as mono device

Jim Henderson hendersj at gmail.com
Mon Apr 22 17:54:21 UTC 2013


I've just purchased an inexpensive USB cassette player in order to 
archive/preserve some audio cassette recordings of some interviews I did 
years ago, and I've run into a slight issue with the detection of the 
device.

The device identifies as a JMTek USB Audio Device (Vendor 0c76, Device 
160a).  I'm using openSUSE 12.2.

When I plug the device in and connect to it with Audacity, and I only get 
a mono channel (rather than a stereo setup).  Looking at the output of 
"lsusb -v", I see that the input terminal is identified as a microphone 
with one channel.  (Output of lsusb -v is at the end of this post)

If I start a Windows XP VM in Virtualbox and connect the device to that, 
it is recognized (in Windows) as a stereo device, and I can record left 
and right channels, so the hardware should be recognized as having stereo 
channels via USB.  There are no special drivers installed for the Windows 
VM (it was just "plug and play").

I'd much rather not have to boot up a Windows VM in order to record audio 
from this device.  I also would prefer to not use line-in, as I almost 
always have ended up with a 60 cycle hum recording that way, and I don't 
get that if I record over the USB connection (the USB connection also 
powers the device).

snd_usb_audio is automatically loading when I plug the device in.

Are there any tricks that I might apply to getting this device recognized 
properly or to diagnose why it's being identified as a mono device?

Thanks,

Jim

--- output of "lsusb -v" for this device ---

Bus 003 Device 007: ID 0c76:160a JMTek, LLC. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x0c76 JMTek, LLC.
  idProduct          0x160a 
  bcdDevice            1.00
  iManufacturer           0 
  iProduct                1 USB Audio Device
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          156
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength           46
        bInCollection           1
        baInterfaceNr( 0)       1
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0201 Microphone
        bAssocTerminal          0
        bNrChannels             1
        wChannelConfig     0x0001
          Left Front (L)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID            18
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          2
        bSourceID              33
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      5 (SELECTOR_UNIT)
        bUnitID                33
        bNrInPins               1
        baSource( 0)           50
        iSelector               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      6 (FEATURE_UNIT)
        bUnitID                50
        bSourceID               2
        bControlSize            1
        bmaControls( 0)      0x43
          Mute Control
          Volume Control
          Automatic Gain Control
        bmaControls( 1)      0x00
        iFeature                0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink          18
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
        bLength                26
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             1
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            6 Discrete
        tSamFreq[ 0]        48000
        tSamFreq[ 1]        44100
        tSamFreq[ 2]        32000
        tSamFreq[ 3]        22050
        tSamFreq[ 4]        11025
        tSamFreq[ 5]         8000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0064  1x 100 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      50
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval               8
Device Status:     0x0000
  (Bus Powered)

--- snip ---

-- 
 Jim Henderson
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