DAC Measurements vs Actual Experience

One particular way in which the PS Audio DAC purportedly falls down is the level of noise, possibly due in some way to the use of a transistor output. I confess that I'm not well versed in circuit topology and the idiosyncrasies of certain configurations, but the reviewer from Audio Science Review speculated that that could be the cause.

Another shortcoming is the somewhat limited dynamic range as compared to the Benchmark. I was especially concerned about this given that I have inefficient (86dB/watt/m) speakers. If my logic is correct, a diminished dynamic range with those speakers might make it more difficult to distinguish transients and also some of the more subtle inflections in music. So far, this hasn't borne itself out in my real-world tests. But that's one way in which I'm doubting my own hearing. *Should* I be able to tell a difference here between DACs? 

The level of detail that each DAC is able to extract from the program material, at least as far as I can discern, is virtually identical. The female vocals in the final 2 minutes of Roger Waters' "Amused to Death" has been my go-to challenge for a component's ability to convey delicate nuance. Neither DAC has demonstrated any apparent advantage. 

As far as stepped volume control goes, the DirectStream touts a "bit perfect" digital method. I'll take their word for it. I'm not sure what the Benchmark's configuration is, but I cannot detect any deterioration of performance at any of the levels I've tried (all further clockwise than the 12 o'clock position). I'm evaluating each at the same volume, or as close to the same volume as possible, such that I cannot tell the difference. I'm sitting in a quasi-near-field position relative to the speakers (~6 feet away), mostly using a volume where the system is conveying energy convincingly, but falls well short of concert-level volume. Evaluations have also been made at more "whisper" levels with volume control being done using my streaming device.  

The differences that I'm honing in on have more to do with grain, soundstage and the admittedly vague descriptor of "musicality" than anything else. But I have this nagging feeling that I need to be listening for something more; something that enables me to look at my experience critically compared to the measurements and say, "Ah, yes. There's where my perception is supported by the data." And yet, that's not happening.

These two units each bring a very strong game. I would probably be quite happy with either of them. And yet, I don't want to get this decision wrong. Maybe what I'm asking for here is a "listening lesson" from experienced audiophiles. But to the larger issue, do perceptions and measurements often disagree? 

Again, the level of noise isn't perceptibly different than that of the Benchmark in my current system

"If that were the case they would sound the same since the Benchmark is considered transparent. The "noise" would not be perceived as noise like hiss or hum but a certain sound like relaxed, reserved, laid back, limited dynamic range."

This may very well be one of those fundamental pieces of information that I hadn't yet grasped. So noise, at least at levels in the -70dB-ish range, is responsible for the relaxed, laid back nature of the sound? And the somewhat stunted dynamic range comes across as a sound that is "less forward."

That's great information. I'm still curious about the imaging, however. Does this also somehow contribute to what I perceive to be a more detailed soundstage? 

Thanks very much for this! 

Thank you all for your insightful responses! 

The synergy between components to one another and the interconnects between them, as mentioned in Michélle's response, is something for which I have great respect. Sadly, it's often blind luck that ends up fixing the problem for me. At least in this case I have an apple to compare to another apple, and I *know* the specific component in the system that's responsible for the change in sound. My collection of audiophile quality cables is small (limited to the Nordost Blue Heavens that I'm currently using, a few offering from Tributaries that have never really sounded good to me, and a few sets of Mogami Gold that mostly see use in the music studio). I feel that, while adding cables to the comparison might not be useful at this point, I might swap them out later in this process and see what the results are. 

The sound of the PS Audio is not what I'd call vinyl-like. And I hesitate to describe it as warm. It definitely has the flavor of a solid state device, but manages not to be "out front" nearly as much as the Benchmark. Again, the level of noise isn't perceptibly different than that of the Benchmark in my current system, which is to say that I cannot detect any noise whatsoever in either DAC. 

And with that in mind, I've decided to swap out the Magnepans for Klipsch LaScalas and see if an extremely efficient horn speaker can shed any light on the noise and dynamic range issues. Or, at the very least, see if any differences are revealed between the two DACs in those specific categories while using the other speakers. Who knows? Maybe that will bridge the gap between the measurements and my perception, even if I may actually be getting to the point (albeit slowly) where I no longer put a premium on measurements in choosing audio components. 

RE: "the 12 o'clock position of the volume control"

As the PS Audio DirectStream has no volume knob, let's call it 70%-90% of full volume for both DACs. 

@djones51, I'm glad you brought up the issue of the source, too. Having little to no information about it, I've considered the 2014 Apple MacBook I'm using to feed the DACs as suspect. I use an AudioQuest Cinnamon USB cable as the interconnect. I stream using Tidal and play my collection of FLAC files using VOX. Could either the computer or the apps be another source of grain and/or edgy-ness? Of particular note, the output volume of each app is set to around the 40%-50% mark in order to be able to turn the DACs up to above the 12 o'clock position. Is this considered bad form? 

I've also heard that dirty power can be a limiting factor for DACs in particular, but for me it's just conjecture at this point. I have no real-world experience regenerating power in any of my systems to know definitively whether or not it's really beneficial, and if so, to what degree. I'm willing to take the word(s) of those who have gone to that length, however, with only the tiniest of grains of salt. 

I apologize to those of you following along if this thread is turning into a free-for-all of topics. But at the same time, so many of these issues are related, so please mention anything that is relevant to the core issue of these two DACs. Thanks! 

A sincere thank you to all of you who have contributed meaningful, well thought-out arguments and information in regards to this issue. 
I suppose I now consider myself a convert. Measurements alone, while still being relevant to the discipline of design and perhaps initial consideration for potential buyers, do not, cannot account for the subjectivity in how we perceive, and thus enjoy, our experiences with our systems. 
It is perhaps commentary on our own egos that some of us (myself included) want our perceptions to align perfectly with what specifications say is the ideal. And yet, it turns out that that ideal is not necessarily what gets my toe tapping. 
Kudos to jjss49 for providing what is perhaps the best analogies I’ve yet heard on this subject. 
Special thanks to djones51 for shedding light on technical issues, specifically how we perceive noise, which really set the stage for me to come to terms with the concept that my preferences don’t necessarily line up with the measured ideal. 
Thanks also go to everyone else whose simple advice to trust my own ears prodded me to do just that. 
I have a few more considerations to weigh, mostly having to do with price and performance value, but it looks likely that the PS Audio DirectStream just found its new home.