Hey Amir, thank you for this and all your reviews,
I came up with a question. RME dac exploits digital volume control, so at full output, it shows its best performance and as volume goes down the performance degrades. the question is: is it better to use a separate preamp (like schitt freya) between RME dac and power amp to retain the best performance?
I would not bother.
Noise will not become stronger as you lower the volume, worst case it stays the same.
So if with no music or very soft music you can't hear it at max volume (or it comes from other sources like active monitor tweeters) you will not hear it when you'll reduce the volume.