DACs, external clocks, and what's what

@kennyc  I think I agree on your first point but respectfully disagree with the second. I don’t see any way to rationalize the different design philosophies between a designer like Ed Meitner, and the designers of DCS products when it comes to external clocks. They have diametrically opposed points of view. I don’t know which is right, I’ve never designed a DAC. I do know that they are polar opposites on the point which is an important one when selecting a DAC.

 ….a hard time understanding the mechanism 

…..its an important consideration in making buying decisions.

This is your own “condition” you put on your decision making process. Personal sonic enjoyment is the goal, understanding the process is an option/restriction.

Maybe a hypothetical example might be helpful.

In opening a DAC design and manufacturing company, we wanted both market penetration and selling our best products we can produce.

For market penetration, we try to keep the cost/price low so more units sold increasing marketing exposure. Targeting the 4k market, we focused on the DAC  quality, but used more moderate cost/quality power supply and clock. To those who want to further our DAC’s performance, we allow for external PS and or master clocks to be utilized as an option. This is our DAC A offering.

To demonstrate our engineering and manufacturing expertise, we designed our best DAC B using top parts including power supplies and clocks. We feel that offering external PS and or clocks offer minimal to negligible sonic improvements so we choose not to offer as additional options.

If we release both DAC A and DAC B at the same time, is one wrong and the other is right? The answer is no. 

Also, your purchasing process seems to separate the DAC then decide on a clock.  Because of limited budgets, the decision should be Both DAC+clock combined simultaneously within budget.

So the decision within budget should be like: DAC A standalone vs DAC B + external clock + cabling vs DAC C standalone vs DAC D + PSU + clock + cabling….etc 

@kerrybh wrote:

I’m certainly not a DAC designer. I think no one knows more about this stuff than Meitner, or the MSB folks, but this is quite confusing, at least to me. Lots of stuff in our hobby comes down to subjective preference, but this seems to be a case where one side must be right and the other is wrong. Which is which? If you think an external clock provides a substantial improvement, how so?

Well for one, I know that my external master clock, the Grimm Audio CC2 connected to my source wordclock input, makes a substantial improvement in my setup. Audio friends of mine are similarly convinced of its merits. So, no debate here. 

As to the how of it, that’s a technical matter I’d rather let Mr. Eelco Grimm and his buddies explain here, here and here. What I can say myself is that of the DAC’s and sources I’ve owned over the years I’ve always preferred the AES/EBU digital input/output route (years back I did use the Audiophilleo 2 with battery PSU over a BNC input), same with my current DAC, and as an S/PDIF protocol that means the source is the master clock to which the DAC is then slaved (contrary to asynchronous USB protocol where the DAC is the master clock).

Even though the incoming AES/EBU signal is reclocked in the DAC and as such claimed, with modern DAC’s in particular, to being more impervious to the clock precision (or lack thereof) coming from the digital source output, I can state with certainty that in my setup context at least the Grimm Audio master clock makes for vastly improved sound quality overall. In which way? A smoother, tightened (but not unnaturally so), more clearly contoured and subjectively deeper low end; a more clearly focused and natural midrange; an even more finely "grained" and delineated top end, and better spatial acuity. Dynamics and tonality appear improved as well. Truly, the presentation as a whole is just more natural, coherent and informative in an unforced manner.

Every connection (connector + cable) is a potential jitter source to boot, but with the Grimm it’s connected with a 75 ohm BNC-BNC clock cable to the pro Marian sound card wordclock input as per the prescribed protocol impedance. What I will look into next with an upcoming new digital AES/EBU cable is to make sure it’ll be assembled by a technician to meet the 110 ohm impedance required here, which is minimizing at least another jitter source. We’ll how that fares out. 

To those who believe an external master clock has to be priced a certain amount to make a worthwhile difference (in which context?, I might add), and can only say the Grimm at ~€1,450 is worth every penny in my system and btw. is the exact same master clock used in their MU1 and MU2. Perhaps that should tell you a thing or two. 

Coming down to it experiences with external master clocks should be viewed in the specific setup contexts, their implementations and products used. What’s the use of generalizations pointing to one direction or another? Do some research and find out how it applies to your system context and compatibility here, and then decide whether to try out a master clock option. It does appear though many are skeptical as to the importance of clock precision with reference to (poor?) theory or very limited experience, which is unfortunate, I find.