How easily can you distinguish between different DACs?

I don't hear vast differences between modern dacs, except for the ones that won't reliably lock on to my digital source. I'm very sensitive to the music randomly cutting out. 

Speaking of Corolla Ferrari comparisons, I think what has to be kept in mind is that when you take a cheap and expensive dac "out on the track" you find out that the Corolla dac with it's cheap tires and regular gas is keeping up with the fully decked out Ferrari dac with it's premium fuel and tires just fine. So the difference would be that the cornering somehow just feels better in the Ferrari and so is a more enjoyable experience that justifies the cost. On the test bench, these cheap dacs are performing brilliantly.

@arafiq

Really? You think that’s the only thing setting a Ferrari and Corolla apart?

No, and you are emphasizing my point for me very well. There are huge and easily measurable differences between a Ferrari and Corolla. Nobody would confuse them even if they were blindfolded, riding as a passenger. The Ferrari accelerates faster, corners better, and sounds and feels and smells different in easily distinguishable ways that are very well known to be within the bounds of what humans can detect. When you get a dac that’s the equivalent of a Ferrari in terms of price and status, and compare it to a dac that’s equivalent to a Corolla, that’s where you find that there’s nowhere near the same difference. The cheap dac does everything as well as the expensive dac in any way you can measure. Often better. If you blindfold someone and have them listen to two different dacs, unless one of them is intentionally non-linear in its response, and the volume level isn’t matched, it’s going to be super tough for anyone to tell them apart. Maybe some people can, but it’s nowhere near the kind of difference you get between a Ferrari and a Corolla. It’d be more like spending 10 times as much upgrading a Ferrari to slightly increase the acceleration and braking so that you can complete a 5 mile curvy course on average 1 second faster. That might be a meaningful difference to a few very savvy drivers.

All dacs are Ferraris these days, except perhaps for some very cheap or expensive stuff that's poorly designed and implemented.

In terms of systems that are "resolving" or "revealing," those terms are not clearly defined. I can make a highly revealing system by making it ultra unstable, or accentuating its response at certain frequencies. Such a system will reveal differences in connected equipment because such a system is way out of spec. It only reveals how well some components can cope with or synergize with its oddities.

@facten 

Over the years I've been allowed to compare various brands including Theta, Wadia, Mark Levinson, and more recently Benchmark. These all sounded fine to my ears, but nothing has ever leapt out at me, even after extended periods of listening. I've heard some beautiful systems in showrooms, and was even allowed to bring in and hook up my cheap front end. Still sounded fantastic. I've lost track of all the different types I've heard at shows and in various showrooms. I've never done controlled blind tests because I never had a claim of a difference to make. I don't know of any controlled tests that have confirmed anything and that doesn't surprise me. Of all the systems I've heard and owned over the years, there seems to be no correlation between the dac and the sound quality. Some of the best sound I've heard at shows involved self powered speakers with their own dacs, or in one case a dongle dac from a Macbook air. I've noticed that even in the 6 figure systems, I still hear the basic issues with the standard 2 speaker configuration in rectangular rooms dominating the overall presentation. 

I'm not going to make a general statement that nobody can hear differences. I'm just saying I can hear a lot of stuff but I can't hear a difference between reasonably competent dacs. If people can hear a difference it just means they are very tuned in to specific aspects of the sound, while able to ignore or adapt to other, louder issues. Decent dacs at all price ranges perform extremely well, and very close to the same. That's not the case with speakers and amps, which are made for all sorts of different listening situations, so they have different power and bandwidth ratings. They also just plain differ a lot in their response characteristics. 

Speakers and amp combinations and rooms and speaker configurations - those make very significant differences to me. Some pre-amps seem to do weird things too. If I go way back to the early 1990s I recall that a Theta dac had more oomph than the analog out of my Sony ES CD player, but that could have just been level matching. I bought it and enjoyed it. 15 years later I still had the dac and compared it to the analog out of a new cheap DVD player and it had nothing on the DVD player. Hard to say why I thought I heard something earlier but I could see how in some cases you could have an output/input mismatch between a dac analog stage and pre-amp input stage. 

Cases where I have heard a difference is things like hooking up a pro-level dac to a consumer level pre. Output is too hot. I then modified the output by bypassing the op-amps and using a cap and a resistor. That's not to spec, and that had audible problems, but even then, not enough to make or break compared to other factors. I was forced to use digital attenuation, which seemed to clear up unpleasant audible issues but then I lost headroom and max volume. I've also tried some crazy output filterless and non-upsampling dacs. Apparently my downstream equipment didn't have a problem with the signal and I can't hear past 20kHz so nothing about it bothered me, which I thought was interesting, supporting the idea that dacs are generally better than they really need to be. 

Good points by all. Some musicians want top notch instruments, others will perform on whatever is available and adjust their style. If any piece of equipment does something you really like, and you can manage the cost, then get it!

James Booker made some recordings at Paramount that have now become an album called The Lost Paramount Tapes. Apparently they had a bunch of great pianos for him to choose from, and he chose a little spinet that was just a set piece. In the eyes of the producers this amounted to James ruining the entire session. When I listen to those tapes it’s obvious to me that James knew what he was doing. There’s nothing inferior about a spinet. It’s just knowing what to do with it.