I'm thinking of hooking up my RME ADI-2 FS with an external amplifier, I found this info on the RME forum.
"CASE 1, analog volume control:
To maximize ADI-2's dynamic range (S/N ratio) it's best to have ADI-2's volume control at 0 dB, using the external ANALOG AMP's volume control to set listening level:
• Set external amp's volume control to middle position or some above.
• Switch OFF ADI-2's "Auto Reference Level".
• Set ADI-2's volume control to 0 dB.
• Select the reference level that fits best to your loudness demands.
• Use the ext. amp's volume dial to control the final loudness.
• Once you start to use any of ADI-2's DSP functions like e.g. the EQ:
- Compensate possible level boosts with ADI-2's volume control until the Level Meter does not show overs.
- Or switch back On "Auto Reference Level" and let ADI-2 calculate the best value.
CASE 2, digital volume control:
If you want to use ADI-2's digital volume control to set listening level, ADI-2 DAC / (Pro) has a clever option that increases the usable dynamic range by 18 / (20) dB: "Auto Reference Level":
• Switch ON ADI-2's "Auto Reference Level".
• Set ADI-2 DAC's (Pro's) volume control to -18 / (-20) dBr. (1)
• Set ext. amp's volume control (or passive attenuators) slightly above your normal listening level.
• Use the ADI-2's volume control to set the final listening level.
Now ADI-2 automatically adapts the reference level for best fit to your loudness demands, while maximizing it's DAC's dynamic range.
If your external amp does not have a volume control, use variable passive attenuators to fit the level:"
If I want to use all functions such as, for example, Loudness on RME I have read that only CASE 2 will work, but what I wonder about is why I should only raise the volume on the amplifier to a little above my normal listening level, why not set it at max? Am I not using the amp to the max if I doesn't?