I've tried 3 different cables. firmware is not flashable - I think I'll take a shot and replace the CM6631A PCB
You can flash firmware there's even mention on diyinhk site that hes got 2 different firmware for it
No experience with CM6631A but it seems any OS that works with USB class 2 should understand the chip without a driver. Yet, at least for windows a driver seem available. What happens when connected to a Windows machine?
I find an obscure hardware fault that suddenly changed the vid/pid string highly unlikely.
@ompv62 : IMHO troubleshooting this DAC should not be difficult.
IIUC: your DAC is plain TDA1543, no clock on that board, i.e. I2S slave. All clocks come from the USB receiver 6631.
6631 has no way of querying the DAC for capabilities in this setup.
The DAC is 16bit only, no chances of 24bit support. Even if the USB receiver receives 24bits, only 16 bits are passed via I2S => used. The DAC datasheet says 9.2MHz BCLK max, i.e. 280kHz sampling rate max. That means whatever the USB receiver sends to it over I2S, it will play.
So everything depends on the USB receiver here. 6631 is well supported in linux, no issues to be expected here. It's all about firmware. You made no firmware changes.
The USB receiver reports its capabilities at USB enumeration. Capabilities will differ for highspeed and fullspeed. What USB speed does your DAC currently run now, did you check that?
Please post output of lsusb -v -d VID : PID as reported by lsusb. Also post content of file /proc/asound/your_soundcard/stream0 . The two dumps will tell almost all we need here.
IIUC: your DAC is plain TDA1543, no clock on that board, i.e. I2S slave. All clocks come from the USB receiver 6631.
6631 has no way of querying the DAC for capabilities in this setup.
The DAC is 16bit only, no chances of 24bit support. Even if the USB receiver receives 24bits, only 16 bits are passed via I2S => used. The DAC datasheet says 9.2MHz BCLK max, i.e. 280kHz sampling rate max. That means whatever the USB receiver sends to it over I2S, it will play.
So everything depends on the USB receiver here. 6631 is well supported in linux, no issues to be expected here. It's all about firmware. You made no firmware changes.
The USB receiver reports its capabilities at USB enumeration. Capabilities will differ for highspeed and fullspeed. What USB speed does your DAC currently run now, did you check that?
Please post output of lsusb -v -d VID : PID as reported by lsusb. Also post content of file /proc/asound/your_soundcard/stream0 . The two dumps will tell almost all we need here.