@audiotroy
I'm still not sure what you're trying to say: "get an integrated amplifier to power your mains then mains then by adding a Dac to the Marantz." Sending the AVR's digital output to the T+A is "adding a DAC to the Marantz," right? Or do I misunderstand?
Let me make sure I'm coming across. I'll be using ONLY the T+A when playing all "serious" stereo content -- vinyl, SACD hirez stereo, streaming digital. No HT electronics would be in the signal path (although hirez SACD stereo would be routed to the T+A DAC via HDMI from the Oppo).
The T+A's embedded DAC/streamer is a class above the Oppo & Marantz DACs, as you'd expect from a $19,000 product designed by a company like T+A. So my goal was to ALWAYS use the T+A to drive the front channels & sub, regardless of source. The Marantz AVR would enter the picture only when decoding multichannel content, sending analog line-level output to the C & rear external power amps and routing a digital front/sub signal to the T+A.
The problem arises when using the T+A to drive the front channels & sub of multichannel content -- such as 5.1 Netflix streamed by the Marantz AVR or multichannel SACD content extracted by the Oppo. It looks now like there's no way to use the T+A's great little DAC & preamp in such cases.
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The Marantz and Oppo are not sending DD-encoded signals.
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@erik_squires Yes, routing the analog output of the Marantz to the T+A would enable HT integration. But that defeats the purpose of inserting the integrated into the home-theater topology, taking advantage of the T+A's power amp, but only after routing the signal through the AVR's DAC and preamp. An analog connection has been my Plan B all along, and I verified that it works, but my OP was posted in hope of figuring a way around that.
Your last sentence I think hits the nail on the head. In general, digital connections cannot be configured as HT bypasses? That's a surprise, but if you're sure of that, I'm SOL. Too bad nobody mentioned that in the lengthy threads I posted here over the last few months describing what I was trying to do. Kinda late now to be rethinking everything, but here we are.
I think the most likely outcome will be that multichannel playback will have lesser SQ than T+A-only "critical listening" stereo. So long as I don't compromise the stereo SQ, I guess I can live with that.
And to be clear, I still love the T+A. It's an incredible piece of grear in so many ways. It'll be interesting to read the first reviews in TAS / Stereophile.