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Disable Power Save Dac2 Pro

soundchippy

January 04, 2021 18:04

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Hi all,

When the Dac receives no input it appears to power down resulting in earth hum through the speakers. This noise also appears approx 5 seconds after a track is paused. The noise instantly cuts out when a track is played.
Having read the below thread i believe that this is caused by the power save feature of the dac chip. I would like to inhibit this power saving behavior. I note that a patch has been posted in the aforementioned thread but I am unsure if it has been implemented in Hifiberryos or how to enable the feature.

Please could someone advise? Is there a dev kernel I can install perhaps?

I am running the latest version of Hifiberryos

https://support.hifiberry.com/hc/en-us/community/posts/115002772529-Disabling-power-saving-or-auto-mute-to-avoid-popping-on-audio-start-

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3 comments

• 0
  
  clivem January 04, 2021 18:41

  Assuming the patch has been applied to the kernel you are using, you just add "no_sby" and "no_pdn" to the dtoverlay line in /boot/config.txt to fully disable power management. (You probably only really need the no_pdn, which stops the charge pump for the output stage being disabled. That's the cause of the noise you hear 5 seconds after stopping playback.) ie.

  dtoverlay=hifiberry-dacplus,no_sby,no_pdn

  Edited by clivem January 04, 2021 18:46
• 1
  
  clivem January 04, 2021 18:43

  I'm not sure whether this still works.... It used to. Create /etc/modprobe.d/snd_soc_core_disable_pm.conf with the contents:

  options snd_soc_core pmdown_time=-1

• 0
  
  soundchippy January 04, 2021 19:12

  Thanks clivem, I created the .conf file and it worked like a charm!