interesting observation with apple usb dac vs google dac with roon

[ampguy]

In one of my audio zones with roon, I use a simple usb to 3.5mm (splits to L/R RCA to amp) dac adapter, and get good sound and 24-48 in this zone.

Just to try, I ordered an Apple usb c to 3.5mm dongle, and somehow Roon shows it as having to do a 16 to 24 bit and 44.1 to 48khz upsample and gives the green indicator instead of the arbitrary hi-res blue star throughout the path. I've reverted to the google adapter. Anyone else ever see this behavior?

 

[voodooless]

Yes, it support max 24-bit 48 kHz. That’s hardly news.

 

[danadam]

Yes, it support max 24-but 48 kHz.

I think the issue here rather is that it upsamples 44.1k to 48k, as if the dongle didn't support 44.1k.

I have a laptop with Ubuntu 20 (admittedly rather old) and ALSA sees it as supporting only 48k:

]$ cat /proc/asound/card1/stream0
Apple, Inc. USB-C to 3.5mm Headphone Jack A at usb-0000:00:14.0-2, full speed : USB Audio

Playback:
  Status: Stop
  Interface 1
    Altset 1
    Format: S24_3LE
    Channels: 2
    Endpoint: 2 OUT (SYNC)
    Rates: 48000 - 48000 (continuous)
    Bits: 0
  Interface 1
    Altset 2
    Format: S16_LE
    Channels: 2
    Endpoint: 2 OUT (SYNC)
    Rates: 48000 - 48000 (continuous)
    Bits: 0

 

[ampguy]

I think the issue here rather is that it upsamples 44.1k to 48k, as if the dongle didn't support 44.1k.

I have a laptop with Ubuntu 20 (admittedly rather old) and ALSA sees it as supporting only 48k:

]$ cat /proc/asound/card1/stream0
Apple, Inc. USB-C to 3.5mm Headphone Jack A at usb-0000:00:14.0-2, full speed : USB Audio

Playback:
  Status: Stop
  Interface 1
    Altset 1
    Format: S24_3LE
    Channels: 2
    Endpoint: 2 OUT (SYNC)
    Rates: 48000 - 48000 (continuous)
    Bits: 0
  Interface 1
    Altset 2
    Format: S16_LE
    Channels: 2
    Endpoint: 2 OUT (SYNC)
    Rates: 48000 - 48000 (continuous)
    Bits: 0

Thank you, yes, this seems to be the issue, and for some reason requiring more sample rate changes for roon than the google usb to 3.5mm dongle dac. (perhaps specific to the specific source it was playing)

 

[sam_adams]

Just to try, I ordered an Apple usb c to 3.5mm dongle

Reviewed by @amirm quite some time ago vs. the Google v1 and v2 adapters.