NOS DAC's without any digital filtering?

You generally won't be able to tell how much modern DAC sucks until you got a really high end accurate system. That means super high damping (making integrating the amp into the speaker mandatory), plus you'll need balanced power (to reduce noise by 10-20db, a miracle btw), you'll also need low jitter input, but that still leaves a huge weak spot the analog XLR cable, so you'll need a very good one there too.

So if your current DAC sounds fine, don't upgrade your gears :)

Sure, and you generally won't be able to tell how much modern homes suck until you move into the Palace at Versailles. That means sleeping in Napoleon's bedroom, sitting in with the Assemblee National for French constitutional reviews, and getting dressed in the Hall of Mirrors. Of course the weak spot may be your wardrobe, so you'll need to drop $400K on some custom-tailored suits at Cifonelli in Paris. So if your current home works just fine, don't start phoning realtors in France.

Or, said a different way, modern DACs don't suck for 99.999999999% of the lifeforms on this planet, not necessarily including llamas and pigmy marmosets.

Actually, some modern DAC's suck and some don't. As engineers say it's all about implementation.

Bombaywalla, your explanations have been super helpful for me. You literally have to spend hours on the internet digging for this kind of quality info.

One last question based on your last response:

Is an upsampled 16/44.1 file just as good as as "hi-res" file of the same sample rate when using a NOS DAC? No advantage at using a "hi-res" track at all???

I can't help but think that, back when NOS dacs were current production, audiophiles were not too happy with CD's sound quality. It just seemed like everyone wanted a new format. By comparison, it seems like audiophiles are much happier with Redbook today than they used to be.

"Is an upsampled 16/44.1 file just as good as as "hi-res" file of the same sample rate when using a NOS DAC? No advantage at using a "hi-res" track at all???"

There's a difference. You can't get more than what you started with. When you start with 16/44 and upsample, its a matter of processing. Thats what changes the sound. Its just like using an eq or tone control. With a hi res file, you start with more information in the file itself. That's why the file sizes are bigger for hi res music.(assuming the same format and compression, if any). Think of hi res as going from 720 to 1080 in video.

Bcgator,
Agree with your post, and it's funny as well.