[ciphercomplete]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif Since when do you get fuzziness interference in a digital signal? And the reason people poo poo optical is because of the belief that optical introduces jitter more than coax due to the way optical must be converted from electrical to optical then back to electrical. I can not determine a lick of difference myself when using my gamma2 with my Squeezebox switching between optical and coax. But really fuzziness in a digital signal?

Maybe I worded this wrong. The fuzziness is not in the signal as in the 1's and 0's. Interference is picked up by the the actual wire and it travels that wire to the next component, the DAC. I never said it effects the signal but it can cause noise (what I should have said instead of fuzziness) on the analog side simply because of this nearby added interference. I look at any interconnect as a potential antenna for noise so you have to make sure they are properly shielded. I just look at optical as another way to reduce noise. It isolates the DAC from the transport by eliminating any electrical signals. The difference I heard from using a optical cable instead of a coax was a further elimination of noise. I don't for one second think that optical "sounds" better than coax under ideal noiseless conditons. 1's and 0's are the same no matter the signal.

 

[m1abrams]

Quote:

Originally Posted by ciphercomplete /img/forum/go_quote.gif Maybe I worded this wrong. The fuzziness is not in the signal as in the 1's and 0's. Interference is picked up by the the actual wire and it travels that wire to the next component, the DAC. I never said it effects the signal but it can cause noise (what I should have said instead of fuzziness) on the analog side simply because of this nearby added interference. I look at any interconnect as a potential antenna for noise so you have to make sure they are properly shielded. I just look at optical as another way to reduce noise. It isolates the DAC from the transport by eliminating any electrical signals. The difference I heard from using a optical cable instead of a coax was a further elimination of noise. I don't for one second think that optical "sounds" better than coax under ideal noiseless conditons. 1's and 0's are the same no matter the signal.

That interference should have no way to travel from the coax into the analog stage on a properly designed DAC. If the noise in the environment is strong enough to influence the coax what is protecting the analog stage from that same external noise? Unless your coax runs are extremely long to make for a very long antenna I just can not buy into the noise increase issue you claim.

 

[RickEC]

I guess whether transport makes a difference or not depends on what DAC you are using. imo, transport will makes no difference if it is connect to either an entry-level DAC (a bottleneck that hides the transport effect), or a very high end DAC (reclocking and jitter rejection). That is why there are two camps here.

In my system, a change of transport significantly changes the sound quality.

I couldn't hear a difference between coaxial and optical in my old set up (Marantz 5001 and Zero DAC). But now, I clearly know optical compromises the signal in my system.

I didn't think there would be any impact, until I heard it.

 

[RickEC]

My coaxial interconnect did pick up noise along the way. Previously, when I shift the cable left and right, the very slight noise goes on and off. A little like the effect of shifting your TV antenna.

 

[ciphercomplete]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif That interference should have no way to travel from the coax into the analog stage on a properly designed DAC. If the noise in the environment is strong enough to influence the coax what is protecting the analog stage from that same external noise? Unless your coax runs are extremely long to make for a very long antenna I just can not buy into the noise increase issue you claim.

OK thats fine not to "believe" it. I can switch immediately between a 2.5 foot optical cable and a 2.5 coax cable on my DAC and I hear added noise on the coax. With no CD playing, no signal, I hear added noise. I hear the difference, I don't have to buy into anything. My system is very low noise and my speakers are quite good so I hear added noise if its present. My DAC is tube based so it is more sensitive than its SS counterparts but that doesn't change the fact the fact that the interference is there.

I use a variety of digital cables. Audioquest and blue jeans optical cables. Moon audio black dragon coax cables. Blue Jeans coax cables. Blue Dragon balanced, blue jeans balanced. Xindak Coax. I have tried them all before settling on optical. Real world experience just does not agree with your theory on what "should" occur.

 

[m1abrams]

Quote:

Originally Posted by ciphercomplete /img/forum/go_quote.gif OK thats fine not to "believe" it. I can switch immediately between a 2.5 foot optical cable and a 2.5 coax cable on my DAC and I hear added noise on the coax. With no CD playing, no signal, I hear added noise. I hear the difference, I don't have to buy into anything. My system is very low noise and my speakers are quite good so I hear added noise if its present. My DAC is tube based so it is more sensitive than its SS counterparts but that doesn't change the fact the fact that the interference is there.

So you wont "believe" that maybe the issue is with the DAC? Many devices even expensive ones fail to properly handle grounding and such and issue would cause what you hear. This does not mean that optical is better, just that the Coax in your system is improperly done.

 

[RickEC]

Quote:

Originally Posted by ciphercomplete /img/forum/go_quote.gif I use a variety of digital cables. Audioquest and blue jeans optical cables. Moon audio black dragon coax cables. Blue Jeans coax cables. Blue Dragon balanced, blue jeans balanced. Xindak Coax. I have tried them all before settling on optical. Real world experience just does not agree with your theory on what "should" occur.

You may want to eliminate noise, rather than resorting to optical.

I refrain from discussing theory. I just put forward my experiences. The only counter argument that I may face is that I am nutz. Maybe I am, I wouldn't know.

 

[RickEC]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif So you wont "believe" that maybe the issue is with the DAC? Many devices even expensive ones fail to properly handle grounding and such and issue would cause what you hear. This does not mean that optical is better, just that the Coax in your system is improperly done.

Hmmm.... with reference to what m1abrams said to ciphercomplete, my coaxial picked up noise when I was using Zero. I am not sure if it is due to a shortcoming of Zero. Probably. I may not need another coaxial cable after all.

 

[ciphercomplete]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif So you wont "believe" that maybe the issue is with the DAC? Many devices even expensive ones fail to properly handle grounding and such and issue would cause what you hear. This does not mean that optical is better, just that the Coax in your system is improperly done.

Well again no. I never said that the interference was of a significant magnitude to cause alarm only that there was slightly more of it.

But we've gone off on too much of a tangent. The op posted about using cheaper players as transports. In my experience cheap dvd players are noisy so I suggested isolating the player using optical. My post was by no means saying that when "I" compare optical and coax in my system that optical sounds like complete silence and coax sounds like cassette tape.

 

[m1abrams]

Quote:

Originally Posted by ciphercomplete /img/forum/go_quote.gif Well again no. I never said that the interference was of a significant magnitude to cause alarm only that there was slightly more of it.

Ok but that does not mean that the issue is not with other components in the chain not properly working. Coax no matter what should not do what you describe, not even a little. So I suspect something else is not playing correctly and it most likely is a grounding issue which would be eliminated by using optical because it does not provide a path to ground. This does not make optical better per se just means it can mask other mistakes in a system. Properly done there should be no difference between the 2.

 

[googleborg]

a resolute no from me unless someone can give me proof equally as solid as why digital works in the first place. my £15 sony dvd drive in my pc manages to move data from dvd to my hd perfectly, if it didn't, i wouldn't have been able to install and play fallout3 (great game!). and accuraterip would be utterly and totally useless. I can only say that if the transport affects the sound then who the hell is designing all these things so poorly - if you have 3 transports and they all sound different then at least two of them must be not working properly, which is kinda shocking to base an entire thing about broken transports. I feel CD players are archaic anyhow, computer audio, please, more time to listen to music

and also, i want to know what jitter sounds like, is there a way to induce really stupendous amounts of it into my digital domain? I have an optical lead and unplugged it, then shone it into my dac and the sound never changed, just garbled & stopped when it was too far away. I figured that would totally bork the SQ - if even if teensy nanodefects can supposedly wreak so much havoc.

 

[m1abrams]

Quote:

Originally Posted by googleborg /img/forum/go_quote.gif a resolute no from me unless someone can give me proof equally as solid as why digital works in the first place. my £15 sony dvd drive in my pc manages to move data from dvd to my hd perfectly, if it didn't, i wouldn't have been able to install and play fallout3 (great game!).

CD Audio and CD Data are 2 completely different beasts and you really can not compare them like that. CD Audio (Redbook) does not have the error correction builtin that data has, therefore your example is invalid comparison.

That said my stand is the transport can only effect the sound via jitter and if you have jitter under control then it should have no effect.

 

[krmathis]

Perhaps not fancy, but you may want one who output bit-perfect audio.

 

[Shahrose]

Quote:

Originally Posted by IPodPJ /img/forum/go_quote.gif That's fine, John. If you are happy with what you have then no one has to convince you otherwise. But until you try it for yourself you shouldn't assume there will be no difference.

I strongly agree with this. I can't explain the technical reasons for it, but I definitely hear differences among transports.

I think hearing for yourself is the best way to judge anything in audio. If you based your decision completely off the data available (that ultimately measure only a few of the many variables involved in SQ), then you would immediately disqualify tube amps, and would be completely wrong in ranking sound quality among DACs.

With such a resolving setup like yours, I am almost certain you'd find SQ variability among transports.

 

[audioengr]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif I’m not convinced with any off these views put forward regarding the need of a quality transport, some of the higher end DAC’s offer 100% jitter ejection by design.

Dont believe it. It's marketing BS. It's never 100%.

Quote:

My current DAC extracts the data from the transport medium avoiding having to extract the clock at all, decoding does not require an explicit measure of the clock frequency. Once the DAC strips the data from the transport clock, it’s mathematically correct but there’s no time in the data.

Not possible. There will always be a PLL or DLL to track the clock, unless the transport is a slave to the DAC, such as with my Pace-Car reclocker. This is the case even with ASRC.

Quote:

Once jitter is removed from the transport clock a poly-phase filter is employed to rate-convert the signal into the new clock domain.

Reduced, not removed. It can never be removed.

Quote:

Both jitter rejection and rate conversion convert all data from the transport at high speed clock speed and then it’s passed on to the modulator.

This sounds like Asynchronous Sample-Rate Conversion to me. This reduces jitter also, but never to zero. Most inexpensive DACs use this technique to reduce jitter. The trick is to reduce jitter without resampling the data.

Steve N.
Empirical Audio