Volume Settings/Control - DAC vs Preamp?

I have a Bluesound Node 2 as my DAC and the Bluesound App has volume control. This is connected to my tube preamp which obviously has a volume control as well. What is the school of thought on volume settings and where to control volume during playback? Should I set the DAC's volume to a certain fixed level (and what should that setting be - low, mid, all the way up?) and adjust volume from my preamp? Or vice-versa? Does it matter? It's way easier to control volume via the Bluesound app as my preamp has no remote but I can live with either solution if it makes a difference.

I have combed through a number of similar posts but not sure I got a clear answer.
Ag insider logo xs@2xitball
This is a great question and someone asked it on the Bluesound forum and the helpdesk's response was controlling the volume using the application should not negatively affect the sound quality. In other words, there's no "bit-stripping". I have also compared controlling the volume between the app's volume control and my preamp and couldn't hear a difference. With all that said, I still always set the volume at max on the app and control it from the preamp, just as a matter of principle.
Like the other posters I have the Node 2 and tried several different settings without noticing any difference in sound quality or noise levels.

I now have it set so the Node 2 sounds the same "level" as my phono stage
- that way I have no surprises or adjustments switching from one to the other
- it’s about 80% of the max output level
- great for comparing digital to analogue - i.e. on occasions when I feel inclined :-)

Hope that helps

Regards - Steve
Thanks everyone, very helpful answers.I had the source volume low and the preamp high. Will adjust accordingly and listen for differences.
I do the same thing,  DAC with volume into a pre without.... I just set the preamp a little louder than I would normally listen and just trim the dac down a few dB's..  -3 to -6 so I can trim up or down via remote on the dac