Which DAC prevails in this chain of converters?

I agree with Trebejo. He has more patience than I do. ;)

Finally, the "piped to preamp" step, which is often neglected in reviews/previews/analysis of DACs. People sometimes go on and on and on about Wolfson this and Burr-Brown that, when it's this output stage here where we separate the men from the boys. Trebejo

In my view this is THE most significant stage in the process. I've come to this conclusion after trying to beat my old 20 bit cdp with newer, more sophisticated cdps. None of them come close and I believe it is the analog output stage that is the difference.

Are you asking, whether your CD player, DAC or receiver is actually converting the signal to analog? Or do you think that each one is doing the same thing in series? With each contributing to a refinement of the signal
Well to my knowledge it doesn't work as a series. The CD player will make the signal analog unless you bypass it's DAC and use digital outs. The DAC will not take an analog signal and convert it to digital then back to analog unless it specifically is capable of doing that. Instead I think it will just pass the analog signal along perhaps?? The analog/output stage of the DAC might get involved but I doubt it. The reciever will accept the analog signal as well and not convert it again, but, in this case the analog output stage will be involved in handling the signal and will matter in the final sound.
To answer your question the CD player.
If you are asking what you should invest in for upgrading. I think the one box CD player with the best transport mechanism, DAC and analog stage you can afford is the way to go.

Only one DAC is active at a time, so you have 3 choices:

1) Run the analog out from your CD into an analog RCA input on your Marantz. Use the stand alone DAC as a paper weight. The DAC in your CD player is the only active DAC in this chain.

2) Run digital out from your CD player into a digital input on the Marantz, leave the stand-alone DAC atop the stack of paper. The DAC in the Marantz is the only active DAC in this chain.

3) Fetch the stand alone DAC from the papers. Run digital out of your CD player into the digital input on your stand alone DAC. Run the analog output from your DAC into an analog RCA input on your Marantz. The stand alone DAC is the only active DAC in this chain.

Compare the 3 options and choose the one you like best.

Good Luck

Marty