Which processor should I use Onkyo 876/Oppo 83

Why not try both? Connect an HDMI cable from the Oppo to the Onkyo, and also connect multichannel analog audio connections, and switch between them to find out which works best with your particular combination of components.

Michael

Just connect to the 876 everything via HDMI and be done with it.

Using analog cables will be pricey and to gain sifgnificant gains there you'll have to step up substaintially which means still more $$$ before you may realize gains using the Oppo's decoder.

Change the pc on the Oppo if anything. That's a bigger help as I've found out on my 980 The Onkyo too likes better pc's. Do those and stick with HDMI as ICs... and do that Audyssey setup as described in my other thread via links supplied by Kal for it's proper setup.

When, if, you compare both type of connection, spend enough time with each to see, hear, the sound quality. Not just the frequency response ( base, mid, treble)but also all the details, the space, etc. If you try quick switching you'll end up with the same conclusion as double blind test: everything sound the same.

Blindjim says that cables will be pricey. It will if you don't already have them, which is the case for most hifi maniac. On the contrary, not being satisfied , that's really pricey.