I did some measurements and some listening in a quiet room, acoustically treated. My old 4310 sounds "just as good" as the 6700 when I just pass a stereo signal from analog in to zone 3 out or to pre-out. When you A-B between the source (Bypassing the AVR completely, taking it out of the chain) and the source trough the AVR at exactly the same level (at 0.1 dB precisely matched) then it is realy hard to tell the difference. So if you put one of these in an untreated livingroom then it is impossible to tell. Not even with really good loudspeakers. The acoustics will mess the sound up much bigger then the difference in DAC. The (audible) differences in converters are not so big as people (like to / hope to) think. (My opinoin as a studio technician) I do measure a little more noise from the 4310. When the AD_DA converters become active that adds 10dB noise. (Pure direct vs Stereo) Both in the 6700 and the 4310 add more noise in modes other than Pure direct. The 4310 is more noisy overall, but still not audible.
If the PCM5102A really has 9dB (?) more noise then you will certainly notice that in a quiet cinema room where you turn up the volume. But only when no audio is playing. The Room tone in a movie always makes more noise still.
And I think 6700 with PCM5102A will be more noisy than the old 4310.
Why do I care? I am going to buy a 6800 or a 4800 for another room. The 4800 has the PCM5102A DACS that may or may not be in my 6700. But from what I learned now I will probably go for the 6800. Not only because of he DAC. But still it was in the mix of things when deciding what to buy.
The AVR-4310 has the PCM1791A for DAC and PCM1804 for ADC. So the DAC IC has SINAD of 100 dB and the ADC has SINAD of 102 dB.
The AVR-X6700H, before the factory fire fore sure would have the AK4458 as you already know, that has SINAD about 107 dB, but the ADC sucks as it is the AK5358 that has SINAD only 92 dB.
I find it hard to tell a difference in SQ comparing my external dacs, tough to tell even using headphones, let alone good speakers. Now if you can hear the noise then sure, it gets easier to tell the difference if one is audibly noisier than the other.
I had a look from various angles between the boards and I think i have the AKM DACS in my 6700. Because in my 6700, the location on the DA board where you see the row of 8 PCM5102A converters in the picture from
Ghost723 does not have 8 chips there, but only 4.
Yes, I can see now that Ghost723's show 8 chips, just that the numbers are not legible, but that does look like the PCM5102A DAC board.
And from what I could see the board matches the picture on the Denon JP site and not the picture from
Ghost723
On this, I don't know what you can tell from that partial view, that it "matches the picture on the Denon JP site.....", but I can clearly see the letter "AKM" and that one IC does look like one that has 48 pins, so it must be the AK4458 DAC IC, because the only other such IC that could have the letters AKM on it would be the ADC, but that AK5358 IC has much fewer pins.
So, enough detective work, yes I am now in agreement with your finding, that you do have the AK4458, the original DAC ICs onboard. Congratulations, not saying it will "sound better", but will fore sure measure much better on Amir's test bench.
I am curious, from that partial view, how the heck can you see the "board" matches the one shown on the Denon website? It does show clearly there is one "AKM" square shape IC that seemingly has 48 pins, so that does indicate it is the DAC IC.
