Thanks for the replies

noromance,

Thank you. I agree and will leave the Dac on playing break in music type files without the amps on.

ozzy

Break in is a subjective phenomenon, as is much in this hobby.  If you think it’s real, I would leave everything on.  Who knows what interactions between components contribute to this phenomenon? 

@ozzy 

streamers and DACs are the easiest components to break in. Just have it streaming 24/7. Nothing else needs to be on. 

From the Lumin owner’s manual:

Powering on

Running-in

LUMIN performs at its best after a running-in period (otherwise known as burn-in or break-in).

The duration can vary depending on the internal components, but under some conditions many users report that the sound continues to improve for a few weeks (200+ hours of playback).

Tips

• Using the LUMIN app you can create a mixed Playlist of different formats. Using music with different sample rates will utilise more of the internal componentry.
• You can put a mixed playlist on repeat and leave playing 24/7.
• During this time, it is best to leave cables connected to your other equipment, but the volume can be off on amplifiers.
• Even after the initial running-in period, leaving the system switched on can help provide a more consistent performance, especially just after starting.

But you know, you could always believe the flat-earthers on Audiogon who pretend to know more about electronics than the engineers who designed this equipment. 

good to finally see someone asking about break in