No.
The Denecke AD-20 is an Analog to Digital converter.
Your DR-2D only accepts analog inputs.
To use the AD-20 you would end up taking an analog signal from the mics, converting the signal to digital in the AD-20, then using another piece of gear converting back to Analog to get into the DR-2D where it will take the analog signal and convert to digital.
It sounds like you are looking for a preamp stage with more flexibility than the DR-2D.
Get an analog preamp. A Naiant Tinybox will fill the role nicely and give you the functionality of the PS-2 in addition.