Hi Darren,
to get the best audio output from the Pi/DAC, you need to set MoOde to HARDWARE volume control and set the volume to 86 as a start point as this is 0db gain, you can adjust this up or down from within MoOde or by using Alsamixer via Putty or similar using your Pi's IP address.
If you do it within MoOde remember to save/refresh the settings.
As I say 86 is 0db, and you can increase or decrease to suit your ears/system as you like. It really does make a difference, and 86 is right for my amp etc. This still gives you the volume control via your amp, although for some reason using my iPad I can control the volume if I Airplay any music to the Pi, otherwise the amp is in total control. Don't use software volume control within MoOde or any other renderer for that matter ( Volumio/RuneAudio/PiCoreplayer) as its rubbish.
This image shows the Digital Output setting I have using Putty to gain access to Alsamixer and confirms that MoOde is set to 86 and 0 gain.
https://mikeyb.smugmug.com/Other/Odd...0Alsamixer.jpg
These show the settings within MoOde
https://mikeyb.smugmug.com/Other/Odd...%20setting.jpg
https://mikeyb.smugmug.com/Other/Odd...%20at%2086.jpg
Mike.