Volume level chain

1+ pragmas, digital volumes that are dithered are significantly better but still I leave all my digital equipment at 90% plus. Digital metering is a big plus in this regard. You can see where you are. In the analog world you just want to match volumes so you do not get a big surprise when you switch sources. Most modern preamps are hard to overload so I would try to keep them as high as possible matching volume to the lowest output source at it max volume. 
For people who do not have digital metering there is a device called the Audiophillio that is a USB to SPDIF converter that controls digital volume with loss of bits. Very cool device. 

Excuse me, without loss of bits.

Thanks for the responses!  
Understood.  Makes sense now.

@mijostyn -   Most modern preamps are hard to overload so I would try to keep them as high as possible matching volume to the lowest output source at it max volume.

My preamp is an older Bryston BP26. Is it modern enough in terms of overload resistance?

The Bryston runs of +-15V rails so will be fine with the full output from the DAC which you can set to 'direct out' bypassing the volume control entirely.

Thanks! Good to know!