I just read the interesting analysis over at ASR.
A possible explanation of the 7705's 4V results vs the 8805's, could be that the latter has a more expensive toroidal power transformer while the 7705 doesn't. That could explain the "clipping" seen when the unit is driven to the absolute max volume -- ie the AV 7705's power supply simply cannot supply any more juice above a certain level.
Ps. I never go anywhere near max volume in my system -- partly not to annoy the neighbors, and also because I'd aggravate my tinnitus if I play things too loud ;-)
In terms of the frequency response, I have certain 'reference' CDs and DVD-As in my collection which go back many years. And I have heard them on many systems. So my brain basically has a frequency 'map' of every track on those discs.
In short, I can absolutely say that all the treble and clarity that I've ever heard on those discs is all present and correct as I would want -- to my brain / ears -- with the AV7705 (digital input from the source to the Marantz as lossless LPCM via HDMI).
However, this is my second AV7705. The first one, which I had to return due to a technical fault with the display output, DID have very noticeable upper frequency roll-off. It was so noticeable with my reference discs that I was almost going to return the 7705 and get the equivalent Yamaha for that reason alone.
But perhaps in subsequent firmware updates Marantz has changed the filter setting in the AK4458 DACs from 'slow' to the steeper low-pass curve option?? (My second AV7705 definitely sounds a lot clearer than the first one did.)
However, whether or not Marantz did change the DAC filter mode, it would be really appreciated if they could please provide us with a user-changeable setting like Yamaha do in their AVRs:
DAC Digital Filter
Selects the digital filter type of the audio DAC (digital-to-analog converter) to have favorite sounds.
Sharp Roll-off Type
Removes out-of-band noises by the filter with steep attenuation characteristics.
It has a tendency to produce clear sounds.
Slow Roll-off Type
Removes out-of-band noises by the filter with gentle attenuation characteristics.
It has a tendency to produce soft sounds.
Short Latency Type
Reduces the audio delay caused by the DAC internal digital filter.
It has a tendency to produce responsive and rhythmical sounds.