I recently got a new Magni + Modi stack for my DT770 250 ohm.
My setup is Laptop > Modi > Magni > DT770.
One thing that I noticed is a subtle Hiss sound, that is only there when playing something (doesn't happen when the headphones are connected but the PC is not playing anything). The hiss sound is not noticeable on lower volumes, but if I hear a very quiet song, and I increase the volume to the 75%-100%, I can hear a noticeable hiss when there's silence in the song.
Is that normal? Is it just the recording? I'm hearing via Pandora mainly (Pandora One subscription with the higher audio quality).