1x Oversampling

Are you sure that it's all just due to "zero over/upsampling", and not overall design? Some years ago there was no digital frontends with upsampling available, so they were supposed to sound better just because of that?

Dmitrydr has a point. It's not solely the zero sampling that makes the AN DACs and others sing. It also must be the use of vacuum tubes and transformers plus overall system design. I've heard it said that the transformer-based AN DACs are uniformally better than the non-transformer-based models. In fact, the non-transformer-based 3.1x got the boot when the 2.1x balanced was released since it was clearly better for less money.

Thanks Budrew. If so, the statement "SimAudio Nova in my living room system sounds sterile, bleached and artificial" is generally just a perception of solid state sound of Nova versus the tubed sound? That's good, I still may love my Nova! ;)
However it seems to be a good idea to get a tubed DAC for certain kinds of music...

About the Nova, please take my comment with a grain of salt - there's a wee touch of audiophile hyperbole in there. When I got my Nova I was totally thrilled with its performance.

That said, I too think a lot of the sound difference has to do with the tubes and transformers in the output stage, and probably the Black Gate caps as well. I hear many of the same qualities in my SET amps that use tubes, transformers and Black Gates.