HifiBerry DAC+ADC pro | Analog input | pops and click sound during playback

[Hammer1656]

Hi all,

I am having an analogue input problem with the HifiBerry DAC+ADC pro sound card. When I select the analogue input in the moode, the music plays through the speakers, but I can hear pops and clicks during the songs. I have tried turning down the volume of the input (either the TV headphone output or a portable music player) but the pops and clicks are still there.

Has anyone faced the same problem and has a solution on how to avoid it?

Thanks.
Regards,
Marek a.k.a. Hammer1656 

[Tim Curtis]

moOde has basic, built in support for the DAC+ ADC but not the Pro.
Maybe there is a hifiberry guide on how to configure the analog input on the board for other than their own OS?

[Hammer1656]

Hi Tim,

thank you for navigating.

Yesterday, I searched web regarding the differences of HifiBerry DAC+ADC and DAC+ADC pro and found out on different media center distribution forum following information.

Difference is that DAC+ADC uses the Pi clock. But DAC+ADC pro has low-jitter dual-domain clock. By default, the HifiBerry clock is selected. 
Following the instructions i I have disabled DAC clock n config.txt file and then the Pi internal clock is in use and during analog input sound playback I did not notice any pops and clicks.

I have added slave=on in this line of config.txt

dtoverlay=hifiberry-dacplus,slave=on

So far I did not recognize any difference in the audio quality, we will see after some time.

Cheers,
M.

[Tim Curtis]

Sure, but don't you want to use the Pro's clocks?
After all you paid a higher price for the Pro version of the board.

You might want to ask on the hifiberry Forums whats needed to configure the analog input to pass audio to the DAC output.

[Nutul]

Sure, but don't you want to use the Pro's clocks?
After all you paid a higher price for the Pro version of the board.

You might want to ask on the hifiberry Forums whats needed to configure the analog input to pass audio to the DAC output.

Looks like the main difference is the PRO is UAC2.0 compliant, and using the Pi clock instead of its own is just like not having it at all...

The fact that using it as master produces clicks/pops is very weird, as it looks like the Pi cannot cope with the request rate from the DAC... (which sounds a bit absurd...)

[Hammer1656]

I found on the HifiBerry page some more info about passthrough using asaloop.

https://www.hifiberry.com/docs/software/...-alsaloop/

By them, it can be easily implemented in SW by following.

alsaloop -r 48000 -C hw:0 -P hw:0 -l 256 -s 0 -U

The fact is that I am not at that level to be sure how to do it, so will search how, where and if possible to implement this in Moode.