I guessed that much. I was referring to an external DAC so the CD player's (or whatever) DAC isn't used.
Okay, then the external DAC is no more altering the sound of the amp than an internal DAC. One could argue that having an extra pair of interconnects and using the S/PDIF protocol to connect the transport and DAC might not be as good of an approach as a direct internal I
2S connection, like in a CD player, but most people have found that it takes a pretty good CD player to beat a modest transport and decent external DAC.
There are, of course, exceptions. Many people in this forum have really liked the Virtue Piano CD player compared to some of their transport/DAC combinations.
Steve