The 861v4 is already getting very accurate 88/24 from the 818v3; and by very accurate, I mean that I am quite certain that the MQA sampling process uses a kernel which spans samples. i.e. the value of the waveform measured by the ADC is integrated over (say) two samples using a specific "shape". The MQA decoding process does the inverse, thus arriving at PCM which is far more accurate than Nyqvist sampling theory would suggest (for a given sampling frequency).

By contrast, the 861v4 ADCs (e.g. IA45 card) use a conventional Nyqvist "point in time" sampling paradigm and, by definition (and with some irony), the "signature" of the ADC is encoded into the digital; and there is no way to correct for this.

In other words, the 88/24 PCM (over MHR) from the 818v3 is going to be far more accurate than 861v4 re-sampled analogue from the 818v3. It's not an experiment that I'm interested in.

Roon Developer and ex-moderator of this Forum
I am #25 in the HH1 photo of fame.