why do transports sound different?
Feb 5, 2010 at 2:38 AM Thread Starter Post #1 of 177

AudioCats

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with the recently purchased Zhaolu Dac, I finally got to compare my Sony changers (CA70es and C601es) as transports. Much to my surprise, they sound quite different.

But why? at the optic output the signals are supposed to be the same, digital is digital, zero is zero and one is one, no?


I guess the next step is to compare my cheapo thin and stiff Toshiba optical cable with the thick and flexy "professional grade" optical....
redface.gif
 
Feb 5, 2010 at 2:58 AM Post #2 of 177
Have someone blindfold you and switch transports back and forth or fake back and forth 10 times and record how many times you correctly could tell the transports apart. Then get back to us.
 
Feb 6, 2010 at 8:16 PM Post #6 of 177
I go with jitter as well. The timing of the digital information is the one definite variable. It is not a transfer of 1s and 0s, it is about variations in voltage or light that represent the 1s and 0s. If they stop you lose your signal, so that is easy to hear. I have not read anything that convinces me the '1s' and '0s' can be misread.

So all we are left with is jitter. Beyond that the problems are

-what does jitter sound like?

-how audible is jitter anyway?

There is no doubt that jitter is present, though the likes of Benchmark and Wavelength state that they have DACs which reduce jitter to zero. They use that to explain why their DACs sound better than others, amongst other reasons. But I have read comparisons of DACs where the jitter is known and 'low' does not necessarily mean 'sounds better'.

It seems to me that jitter and sound quality is an area that needs far more study, but it is the most likely cause of a difference in sound with transports.
 
Feb 6, 2010 at 9:10 PM Post #7 of 177
You are not crazy. Transports can have a very significant impact on the sound, even though they really shouldn't. How low is the jitter, how good is the power supply, how good is the clock, what are the quality of the components used, is there noise? These are all thing you need to know about the digital output section of your transports, because they all affect the S/PDIF signal coming out of them.
 
Feb 6, 2010 at 9:29 PM Post #10 of 177
Quote:

Originally Posted by pne /img/forum/go_quote.gif
Jitter


Quote:

Originally Posted by audioengr /img/forum/go_quote.gif
jitter


Thanks for the responses
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I recognise that both jitter and Wham cause a drop in sound quality.
 
Feb 6, 2010 at 9:38 PM Post #12 of 177
Jitter – not just the amount, but also and even more so the spectrum. Just my guess: I do hear sonic differences with different transports as well, and jitter is the only explanation that comes to mind.
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Feb 7, 2010 at 2:09 AM Post #13 of 177
Nice isn't it, all those 'scientific' types who are sure you are imagining things even though they weren't there.

I think another explanation could be different levels of RFI lifting along with your signal and disrupting your DAC.
 
Feb 7, 2010 at 2:58 AM Post #15 of 177
Well, the reason they call us crazy and frankly have every right to, is because the people who make these claims such as Steve Nugent can't be bothered to take the time to actually measure the jitter reduction he claims his products reduce.

It's a great marketing claim to say a product reduces jitter, but if you can't back it up with empirical evidence, don't make the claim. Just be honest and say "our products sound better, have a listen for yourself". Since jitter is the most probable cause, it makes sense that it would be the #1 reason transports sound different, and it probably is. But if a company can't back up those claims with evidence, I wouldn't buy a product from them because they have no integrity.

I actually had respect for Empirical Audio and their ingenuity for thinking outside the box, until I read Steve's posts at Dan Lavry's forums.
 

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