Amanero firmware or design issue or something else

I'm experiencing the issue with cracked sound in one channel of my DAC (thru Windows Direct Sound only / ASIO is OK).
Left channel sounds distorted at the Windows Default Format Test tone when I select greater than 16-bit/44.1Khz sample rate. Right channel is OK.

I've localized the root cause is Amanero USB input +- Direct Sound.
(1 it is not the Windows driver - the same thing happens on diff PC/Windows7/10;
2 not the AK4137->D/A->Analog path - because it sounds good when S/PDIF input AK4118 gets used)

I've already tried to flush bunch of different Amanero firmwares
Amanero Technologies
The results are all basically the same: either there is no sound at all or there is same issue.

The Amanero USB receiver is 100% original - got it from from their .com.
I have the AK4137 (and whole DAC) clocked asynchronously from its own master clock.

Well ... via ASIO/WASAPI everything sounds and measures OK. Just the Direct Sound via USB and one channel.

Stepped on the rakes 😉 Gentlemen, need some advise/clue/hint from you.

Thanks in advance!
 
If you turn down the volume in Windows does that have any effect on the distortion?

Is the AK4137 configured to expect other than I2S PCM format (maybe LJ)?

Why use direct sound at all given that sound quality suffers compared to properly configued ASIO?


Also, not about Direct Sound-related distortion, but there should be no reason to use ASRC with asynchronous USB. Amanero can be configured to use an external clock source, which ideally should be derived from the dac clock. Then ASRC would only be needed for SPDIF.
 
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Mark, is that difficult to configure Amanero to use the external clock? Could you give me the idea how to do that?

Its one of the firmware options. IIRC, then you just inject the external clock into the MCLK pin the Amanero. One of the Amanero status signal pins (F0?) indicates which MCLK frequency family it needs (44kHz family, 48kHz family).

If going to that trouble then the Amanero should probably also be modified, or a USB 'Y-cable' used, to run Amanero from a clean +5v linear supply rather than from USB power. That can make a significant difference if one is not galvanically isolating and reclocking Amanero I2S output.