Maybe I misjudged the combination of these specs.
I now have the DAC2 at position 3: (Attenuator = 20dB), which means a Gain of 4dB, 1.2Vrms.
Poweramp is at Bypass/Unbuffered.
Volume is now at aprox. 11 o'clock for slightly above normal level.
So far no sign of Hiss (which I only noticed at the...