DAPHILE volume control

Hello community,

Do any of you know the 'technology' used by Daphile for volume control?

I hear a substantial loss of quality when I go from 'Off bit perfect' mode to 'On at 100%' (loss of dynamics, the sound is grayer, more subdued).

Do you know:
— if Daphile uses dithering like Linn so as not to lose resolution by quantization?
— under which bit resolution does Daphile control the volume?
— if a pure digital TC electronic BMC-2 type controller (In and Out in SPDIF) could do better than Daphile?

Thank you all!