Transport + DAC Question

[admin_exported]

Hi All

I have a Beresford 7520 connected to a CA 540D for transport duties, i can get a Roksan kandy MKIII CDP very cheap, will this improve the sound replacing the CA as a transport, or will it sound better without the DAC which i would just use for PC USB duties?

Cheers

 

[jaxwired]

Hi wickerman,

Well, logic would dictate that all transports sound the same since the only thing they do is read the 1s and 0s and send those to the DAC.

HOWEVER, I've tried a couple and they sound different to me. A real head scratcher. And the only explanation I've ever read is that transports introduce jitter and different levels of jitter makes them sound different. Jitter has to do with clock synchronization and the consistency of the data feed to the DAC. My particular DAC claims to be immune to jitter though, lol, and transports STILL sound different to me. Really makes some good ammunitiion for the "it's all in your head" camp.

My experience is that when I listened to the transports as CD players without using my DAC, Whatever character they had, when I used my DAC, there was still an element of that same character. It definately sounds different with the external DAC, but the original character of the CDP is somehow retained. So for instance, if the CDP sounds a little bright when used stand alone, it will still sound that way via an external DAC.

So, my advice is that a new transport will impact the sound. I can't tell you if you will llike it more or less though. That would require an audition...

 

[scene]

Jitter affects digital sound. If you have periodic jitter, i.e. your digital clock's timing cycles around the ideal, you will get something equivalent to the wow and flutter you get from old analogue sources - think of a record with an off-centre hole. Random jitter, where the source's clock chip is just not very accurate, will raise the noise floor of your signal. Having a clock that's off speed, i.e. too fast or slow, should have just the same affect as having a record played to fast or slow, the tone will be raised or lowered.

In reality all clocks have some combination of periodic and random jitter and will not be 100.000000% exactly the same speed. These variations are small and may not be discerned as making the music sound "wrong" or off-key, however they will potentially give a source a particular characteristic sound. Tests show that 10ns jitter on a pure sine wave makes an audible difference, but that it takes 20ns jitter on a piece of music for it to become noticeable. I suspect between these two lies the range of "characteristic sound".

Cheaper transports typically have more jitter as their components are cheaper and clock chips more susceptible to voltage fluctuations and RF, or just not so accurate.

(sort of jinx with jaxwired)

 

[manicm]

Did the Beresford really improve the sound of the CA540? I would be really surprised if it did.

Not to take away anything from the Beresford but many underestimate the built-in DACs of some CDPs.

 

[idc]

jaxwired:

.......My experience is that when I listened to the transports as CD players without using my DAC, Whatever character they had, when I used my DAC, there was still an element of that same character........

That, to me suggests it is your ears jaxwired. Since so much effort has gone into jitter reduction by Benchmark, it is hard to think of a way the transport can inject any character into the DAC.

 

[Anonymous]

Transports definitely make a difference. I have compared a CA DVD89, Arcam CD 73T and my current CA Azur 550C using a co-axial input into my Russ Andrews DAC1USB.

The DVD player as a transport was clearly inferior to the CD players as transports.

My CA Azur 550C has been a noticeable step up in quality over the Arcam as a transport as well, being much more detailed and dynamic as well as spatially more rewarding. Whether this was because it is was better or because the Arcam was getting long in the tooth, I'm not sure, but I only bought the CA as a replacement because the Arcam mechanism went kaput, so this may explain the differences I heard.

CA claim their new servo 3 mechanism is a step forward from their old models. This I cannot vouch for as I haven't tried one of the old series, but my DAC has clearly highlighted differences between transports every time I've tried. These are not "in your head" differences - more like "having your ears syringed" experiences. Digital cables makes a difference as well.

 

[idc]

Any thoughts on why the transport makes a difference? Jitter is an explanation, but with the likes of the Benchmark DAC, jitter is removed, so we have lost taht reason.

 

[Anonymous]

I think that the whole digital signal transfer process is probably much more complicated than just being a series of 0's and 1's. I'm not clued up enough, and I've not yet read an argument that convinces me or that I have understood well enough, to explain why transports, cables and dacs sound different. The best analogy I can give is based on what many musos say about the musicians that get the musical message across in the best way: it's not the notes they play, but the ones they leave out and the space in between them that matter most.

The inference of this is that digital sources and everything in between somehow add/subtract from the music and mess up time in some way.

I'm not sure that a jitter-free dac is necessarily the answer, because it still has to re-assemble the signal it receives in some way and this is only an interpretation of the original.