I wonder what is the highest frequency and at what quality from the 768kHz soundcards, e.g. RME ADI.
That card showed circa 140kHz bandwidth for either 384k or 768k sample rates, which may align with the bandwidth available from reasonable audio quality opamps like NE4435. If that was the case then the opamps seem to have become the limitation.
Thanks a lot. Please have you done spectrum analysis of the output of the 100+kHz signal at the 768kHz rate? I am asking because of AK4493 in oct/hex mode - oversampling filter bug? - Page 1 .
No, I just gleaned the bandwidth info from the manufacturer operating manual as I was interested to see how they likely performed.