About using the Adcom as a phono preamp you should be using a tape out on the Adcom to go into your HK's tape in. Don't use the pre out on the Adcom. The volume on the Adcom would be out of the path and just turned all the way down.
Which DAC processes CD audio - receiver or DVD?
I have a Denon DVM-1815 DVD/CD changer with 24-bit Burr-Brown audio DACs connected to an HK DPR-1001, which also has audio DACS. The audio connection is via coax cable. When I play an audio CD, which DAC is doing the conversion? I chose the Denon in part because of its excellent DAC. Is there some way to control which DAC does the conversion?