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
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