In my opinion, comparing any AVR/ AVP to a simple DAC is not a good comparison. AVR/AVPs cannot and will never perform at that level and I will tell you why. For a DAC the SPDIF signal comes in and goes straight to the DAC. After the DAC it goes through an I/V converter and out. Pretty straightforward, no post processing going on so nothing to degrade the performance. Now lets look at an AVP for comparison. Bitstream comes in and goes to the DSP. The DSP decodes and renders the various channels. The output of that then goes through a bass manager where crossovers are applied, the bass is summed and redirected. The dedicated LFE channel is also put into the mix where it gets summed as well. After that it all goes to EQs, Room correction, time delays and finally sent to the DACs. Don't be fooled into thinking that all this happening in the digital realm is any different from what would happen in the analog realm. DSP algorithms are just mathematical expressions of an analog circuit and since a DSP cannot operate above 0dbfs a lot has to be done to prevent it from clipping. You can't sum 16 channels of bass without lowering the level down quite a bit, which means you have to lower everything to match. Add in EQs, you can't boost a signal in a DSP, so what you are doing is actually cutting everything around the center frequency to allow the chosen frequency to appear boosted. Room correction works the same way as an EQ. I feel confident that most here are aware that when you lower a signal in the digital realm, you loose resolution. EQs and room correction add phase issues as does time delays. So all this summing, crossovers, EQs and delays mean a lot of signal manipulation before it ever ends up at the DACs. If you were to do everything being done in a DSP in the analog realm, you might be surprised at how bad your performance actually would be.
Bottom line, because of all the signal manipulation going on in an AVP/AVR, it will never equal that of a simple DAC.
Lonnie