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Jitter, CDPs, Transports and Streaming

In my personal, digital audio journey, I have found that I prefer the sound of CD players over streaming through my computer to a DAC. I have tried 4-5 different steaming/transport configurations and found CD players to sound more natural with less digital glare and cause less listener fatigue in each comparison I made. I attribute this to jitter and the increased levels caused by noisy computer environments and the additional circuitry and wiring between a source/transport and DAC. I am sure component quality plays a role here and I’m sure there are CD transport and DAC combinations that sound better than some standalone CD players.

I got to thinking that DACs have buffers that they read from and realized that the upstream source shouldn’t matter, but they apparently do. Why doesn’t the buffer completely eliminate the relevance of the quality of the source? Are there types of DACs, like asynchronous DACs, that make the CD transport or computer source quality irrelevant?
128x128mkgus
mkgus's avatar
mkgus OP
324 posts
 
This is exactly why I prefer DAC’s that have no reclocking on the S/PDIF inputs. This way you can drive those inputs with lower and lower jitter sources and reap the benefits.

Interesting. It makes a lot of sense. Does that mean it doesn’t have a buffer it reads from - the DAC just takes the data stream and converts it to analog in real time?
audioengr
3,282 posts
 

There is always a small buffer of a few words, but it is clocked synchronously with the clock recovered from the incoming stream by the "Receiver" chip. The clock is contained in the S/PDIF data stream and it is recovered by this chip.  Some of the newer Receiver chips can reduce jitter even more if they are implemented on the circuit board optimally.

All DAC's work basically in "real-time", even if they have asynchronous buffers.  The buffer delay is much smaller than anything audible.

Steve N.

Empirical Audio

mkgus's avatar
mkgus OP
324 posts
 
Thanks, that makes things more clear. So even though everything has a buffer, it sounds like it is operating off the clock of the source, unless it is asynchronous which reclocks the signal with its own (hopefully) high precision clock. Is it safe to say that all CD transports will sound the same if one uses an asynchronous DAC?
audioengr
3,282 posts
 

Every source, whether it's a Transport or a computer server will sound different because the clock circuit designs are different.  Some are better than others, so they will have lower jitter.  A DAC that reclocks asynchronously will usually be affected by this jitter. I have only evidence of one DAC, the Benchmark DAC3, that is generally immune to incoming jitter, but this conclusion is only anecdotal based on customer feedbacks.  I have not tested this myself.

Steve N.


Empirical Audio

mzkmxcv
777 posts
 
I have only evidence of one DAC, the Benchmark DAC3, that is generally immune to incoming jitter

It’s J-Test shows jitter reduction at >-148dBFS, amazing. However, the $77 Topping D10’s J-Test shows reduction of jitter down to -128dBFS. So, if they hear no jitter on the DAC3 and do hear jitter on any other competent DAC, it’s simply placebo, as our hearing in even a treated room is not better than 100dB.
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