I have struggled with the issues discussed in this thread repeatedly (not the question of the OP). One thing that has become very clear to me is that a digital reproduction system is not a purely digital system, but a mixture of digital and analogue. That’s why digital cables can have an influence (not in the digital domain, but in the analogue). dCS for example recommend U/UTP ethernet cables, as screened cables undo the isolation measures dCS have taken in designing the ethernet input of their DACs.
To put things into perspective. Different parts of an audio system have different levels of influence on SQ. I would personally put them in the following order of decreasing influence:
- Room acoustics (influenced by room treatment) - by far the biggest influence
- Speakers
- analogue equipement (amplifiers)
- digital equipment (DACs)
- cabling
As long as one has not optimized the level above, it makes little sense to work on the level below. It is unlikely that one will hear the difference.
I would assume yes. Stray electrical disturbances are likely to influence Mic preamps. But that influence is probably many factors smaller than the effect of room treatment in the studio, choice and placement of mics etc.