The following operation is in the <span style="color:red;">config.txt</span> file
REMOVE THE DRIVER FOR THE ONBOARD SOUND
<pre>
sudo nano /boot/config.txt
#Remove the line or add the '#' at the begin of this line;
#dtparam=audio=on
</pre>
CONFIGURE DEVICE TREE OVERLAY FILE
<pre>
#Add the following line at the end of config.txt file;
dtoverlay=hifiberry-dac
#Save config.txt file(Ctrl-x then Y), then reboot raspberry pi
sudo reboot
</pre>
==Volumio (Version: 2.118)==
Select the<span style="color:red;">“PLAYBACK OPTIONS”</span>menu, Turn on <span style="color:red;">"I2S DAC"</span> and select <span style="color:red;">"Hifiberry DAC"</span> under<span style="color:red;">“DAC Model.”</span> Then reboot and you are done.