Don't think it's computer, I tried 2 computers (macbook and windows PC), no difference, and optical out from my TV.
I tried plugging off for around 3 hrs, no difference. Today I added a headphone amp to the setup, but I don't see how this can have impact in a setup: dac -> preamp (tape out) -> headphone amp
I tried plugging off for around 3 hrs, no difference. Today I added a headphone amp to the setup, but I don't see how this can have impact in a setup: dac -> preamp (tape out) -> headphone amp