DAC NOS vs DELTA SIGMA, Who is the real winner...

[KSTR]

I'll admit though, I don't know if such setup happens in practice. It may be that you always get either both of them or none of them.

So far, I haven't seen any DAC which has a proper anti-image filter but shows the ZOH roll-off. This combination doesn't make to much sense anyway.
For filterless NOS, ZOH without droop correction is very common, but ZOH with droop correction basically non-existent.
For filtered NOS DACs, ZOH correction is normally implemented. The filter is analog and thus for fixed frequency, either 44.1kHz or 48kHz (or switchable), sometimes a compromise filter is used to handle both.

This also applies to emulated NOS modes like the those from AKM AK4490/AK4493 etc DAC chips. No filter and no ZOH correction (however, there is a final on-chip "two-tap FIR" and of course an analog filter at 100kHz or so, typically).

 

[zany.ninja]

Just thought I'd share an interesting observation from Archimago's blog about the difference in peak/rise times in square waves across different filters, including the NOS filter/mode:

 

[staticV3]

Just thought I'd share an interesting observation from Archimago's blog about the difference in peak/rise times in square waves across different filters, including the NOS filter/mode:

View attachment 466361

Zero implications for playback quality, but yeah. It's interesting.

 

[voodooless]

It does make for great propaganda material for the NOS crowd, though.

 

[danadam]

the difference in peak/rise times in square waves

"square". Square wave consists of specific harmonics. The one used above has a ton of aliasing. Here's the same thing recreated (non-bandlimited square, RME Adi-2 Pro NOS -> E1DA ADCiso):

With properly bandlimited square wave the NOS version will look anything from slightly worse:

to really bad :

And properly bandlimited square wave and Sharp filter for comparison: