Most of my replies are answering multiple other questions, and people that are “confused” and want to know every single detail as to why I would even want to add a component. Then I give more information, then they have even more questions. I saw #10 post but am continuing to reply to others that seem to need more information. I could have just taken crutfields advice and moved on but I figured more feedback the merrier.
I understand your frustration in trying to get a simple answer to a simple question. However, you have to understand you are trying to do something that is rarely done, and that's why people want to know the what and why, in order to address your concerns properly.
Regardless of the questions I asked, I did answer your questions about "signal degrade" in my first response, and repeated the same answer when I asked questions of my own, that only meant to understand more about your intent in order to propose a better solution if possible
So now I understand the reason you want to add a prepro is that you run out of inputs on the AVR. Again, I am repeating the third time, as long as you select the analog bypass mode there should be not "signal degrade" that is audible. If you use the multi channel analog then you don't have to select that special mode.
I qualified my response with "audible", because otherwise I would have to say what Mikado463 said, "maybe".. Every time you insert something in between two devices, you will have additional "insertion loss". Assuming you use good quality connectors and you make sure they are all tight fit, then the very minimum (likely not even measurable) insertion loss in this case should not have any audible effects.
