[kirch]

If I use a DAC, should the Transport itself have any affect on sound quality?  Logic tells me it shouldn't or shouldn't have much, but it sure seems to.  Using different CD Players - or transports - thru the same DAC produces noticeably different results in my system.  I don't understand why this is.  Apparently I have a fundamental misunderstanding of exactly what a DAC does.  I always assumed the DAC took over the "processing" of sorts from the CD Transport, and that the transport did nothing more than read the info from the disc and forward it onto the DAC, bypassing the CD player audio processing center (for lack of a better term) completely.

Anyone wanna help clear this up for me?  Appreciate it!

[walkern]

Different devices can vary in terms of how accurately they read the data from the disc.

In addition, different transports schlepp the data out to your DAC with a timing signal, and that timing signal can include all sorts of issues (Jitter).

In general I've found most DVD players (except the old Pioneer Stable Platter design) to be less effective transports than dedicated CD players... and as a general rule, the better the CD player, the better it was at serving as a transport. 

From an engineering standpoint one would think that all transports that could read and send the data would be identical, but that just doesn't turn out to be the case.  And to make matters more complicated, the digital interconnect you use has the potential to mess up the sound as well.

Good luck!

Neil

[kirch]

Interesting. And re the digital cable, it's beyond me how 0s and 1s can be anything but. It's always something.

Thanks!

[richidoo]

An old but good article about transports
http://www.stereophile.com/reference/368
See the footnotes for more info.

Some modern DACs have the ability to clean up the digital signal by various methods, so that makes the transport less important. The ESS Sabre chips are very good at this. On older DACs the transport and wire are usually very important.

[skunark]

In the end... or at the start ... it's all about how reliable the transport can deliver the bits with the least amount of jitter.    You can look at the different interfaces like I2S, AES/EBU, Coax and optical, each one has their strengths and weaknesses and the new DACs that resynchronize the feed can clean up the jitter for the source synchronous solutions.   

[Nels Ferre]

Years ago, I used a Soundstream DAC ($699) fed by a Harman Kardon CD player used as a transport ($699.)

When the HK but the dust after years of heavy use, I bought a $350 Sony ES machine. That I was disappointed is putting it mildly.

As with all things audio (and life in general) it is all about synergy. Not every DAC will be happy being fed by every digital source.

[kirch]

Good information.   I was most curious about what parts of the cdp is used when attached to a DAC.  Cabling and jitter (or lack thereof) are the most important aspects of a transport? 

 

[NekoAudio]

Different transports will output digital signals of varying quality. The theory is certainly just 1's and 0's, but timing (e.g. jitter), signal fidelity, signal noise, shield noise, picked up interference, physics (a digital signal is still an analog thing), and circuit or algorithm implementation nuances can all affect the signal.

So, all parts of the equation can matter: the transport, the cable, the DAC. Obviously, some equipment (and their implementations) can better handle a wider range of situations, or worse situations. For example, hard disks have better error detection and correction than CD-ROM drives. Cables with better shielding, or a balanced configuration, will do better at rejecting noise. And DACs that use their own internal clock will be less susceptible to high jitter S/PDIF signals.