Since you likely are never gaining your input source voltages, it doesn’t really matter if the preamp is active or not.
How are you unhappy if you stated you don’t know what you don’t know? Try not using the pre-amp and drive your amp directly with the Dave (keep music at max level and turn down the level on the Dave. Compare that with using a preamp.
A preamp is never improving the sound quality, so unless you need amplification or a different output impedance, a preamp can only harm the sound. If you get a good enough preamp, then any harm is negligible. So, it’s main duties are simply volume control and source switching.
I am unaware if the Dave takes care of intersample overs; if not, it’s best to lower the volume on it to -3dB.
So again, try comparing using the Dave directly against using your preamp, unless there is some crazy issue with output impedance, a preamp added will never sound better (unless the volume control on the DAC/source is poorly done), so directly from the Dave should sound the best possible.
