The new Spectral 4000 professional, if you can get one. I hear the wait is 1yr.
The only DAC's I'm aware of that meet most of these criteria is the Northstar 192 DAC and the Northstar Extremo. They both have discrete output stages. Very smooth on vocals and great layering once they are modded by EA. The 192 needs a few mods and then it is superb. The Extremo needs a lot more mods, so I'm not doing any more of them. You forgot to mention DC-coupled - this is a must.
The I2S interface on the 192 does no upsampling, but only supports 24-bit data. The S/PDIF and AES inputs automatically upsample to 24/192 and they do an excellent job, one of the best upsampling chips available. I would recommend driving the I2S from a computer converter with SRC upsampling in software. You can buy a stock unit at:
The problem is that there is no DAC I really like and would be willing to spend money on to replace existing one I have, have not heard one yet.
Based on limited experience, it would appear I do not like upsampling, and majority of todays DACs do it one way or the other.
And I am not interested in DSD, only 16/44.1 and 24/96, so it makes no sense to spend $ for something that will be useless for me, yet represents a good chunk of the cost.
I do know that I prefer balanced design.
I am trying to figure out if there is something in professional gear for me.