aes/ebu vs spdif with dacs other than benchmark?

[music_man]

the gentleman from benchmark explained in another thread that aes/ebu or s/pdif makes no difference when using the dac-1 because it uses ultra lock technology.

i was wondering if this is true of other modern dacs.
would the central station be much better if it had a aes input?

edit: i forgot to mention i was comparing aes/ebu on xlr vs. s/pdif on rca both with the same quality 1 meter cables.

music_man

 

[music_man]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif AES/EBU is essentially "balanced digital" (via XLR, TRS, or some proprietary connector) but the difference between AES/EBU and S/PDIF is so minimal that it's not worth worrying about.

i was wondering if everyone else agrees with that statement?

music_man

 

[audioengr]

Ultralock, which is asynchronous upsampling will remove most of the jitter on the incoming signal, whether it's S/PDIF or AES. The better the upsampling clock is, the less jitter will result. It's quite good, although I have not found that it removes ALL of the jitter.

IMO, In some systems where there is significant ground-loop noise or common-mode noise, the AES interface may introduce a bit less jitter, which may make its way through the upsampler via ground-noise or other means. Your system must be quite resolving and noise-free to hear the difference though.

 

[music_man]

what i was asking was about dacs that do not have the ultralock.
do those dacs exhibit a sonic difference between their aes/ebu and s/pdif inputs?

also i was wondering what technology the presonus central station uses to reduce jitter if any and if it is effective as the ultralock technology.

music_man

 

[thomaspf]

As far as I know Ultralock is simply a marketing term for using an AD1986 asynchronous sample rate converter to decouple the input clock from the actual conversion clock.

For any unit using a similar design the difference between AES and S/PDIF will come down to how the difference in jtter on the incoming side will manifest itself in different noise levels in the asynchronous sample rate conversion. These noise levels are very low and the difference is very likely beyond the hearing threshold.

However, be aware that on a unit with ASRC even a perfect input signal can result in artefacts if there is a difference between the incoming rate and the locl DAC clock.

Cheers

Thomas

 

[music_man]

i know dacs with asrc attempt to get around the interface. i meant dacs that only oversample. not upsample or reclock. instead of mentioning benchmark as reference.

going from analog single ended to balanced made a difference.
i cannot hear a difference between the two digital interfaces on any of my dacs. should i? is one type of interface generally regarded as superior to the other. regardless of what dac is used.

music_man

 

[music_man]

i read about this somewhere else. the answer is, aes should introduce less jitter than s/pdif under most circumstances. whether this will be audible or not depends on a number of other factors.

music_man

 

[audioengr]

Quote:

Originally Posted by music_man /img/forum/go_quote.gif i know dacs with asrc attempt to get around the interface. i meant dacs that only oversample. not upsample or reclock. instead of mentioning benchmark as reference. going from analog single ended to balanced made a difference. i cannot hear a difference between the two digital interfaces on any of my dacs. should i? is one type of interface generally regarded as superior to the other. regardless of what dac is used. music_man

Depends entirely on the implementation. If they are both well-implemented, the AES should be a bit better due to the common-mode noise rejection.

Steve N.

 

[EliasGwinn]

Music_Man,

The debate between XLR (balanced) transmission vs. coax transmission is completely seperate from AES vs. SPDIF. AES and SPDIF formats are not mutually exclusive to XLR, coax, etc. AES can run on unbalanced coax, balanced XLR, optical, etc, and SPDIF can also run on all these mediums (however, it is rare to see SPDIF on (XLR) balanced).

AES and SPDIF have no inherent sonic differences. They only differ by their metadata and binary voltages. Metadata are status bits which describe the nature of the the data (consumer vs. profession, copy protection on vs. off, etc). The binary voltages can have an affect on the sound if your running a long line. The difference in sound will be obvious (data drop out, clicks, pops etc). It won't be a 'coloration' difference. AES runs at 4V logic and SPDIF runs at 0.5-1V logic. For this reason, AES is advantageous.

Coax (unbalanced) is advantageous over balanced transmission for two main reasons:

1. Balanced cables has much higher capacitance and higher impedance which will round-off digital transitions (aka jitter).

2. Coax has better shielding to protect from EMI

The only reason balanced transmission exists is because the Audio Engineeing Society wanted to create a digital transmission standard using common cabling (XLR). At first, it didn't work so well because certain lengths of cable would cause perfect reflections/cancellations because of improper cable type and termination.

With all that being said, it should be noted that no matter what type of interconnect used (and no matter how expensive the cable is), the amount of clock jitter inherent in digital interconnecting is WAY too high by orders-of-magnitude for any converter chip. Without a properly designed clock recovery system, even a $30,000 cable can't save the audio!!

Thanks,
Elias

 

[EliasGwinn]

Quote:

Originally Posted by thomaspf /img/forum/go_quote.gif As far as I know Ultralock is simply a marketing term for using an AD1986 asynchronous sample rate converter to decouple the input clock from the actual conversion clock. For any unit using a similar design the difference between AES and S/PDIF will come down to how the difference in jtter on the incoming side will manifest itself in different noise levels in the asynchronous sample rate conversion. These noise levels are very low and the difference is very likely beyond the hearing threshold. However, be aware that on a unit with ASRC even a perfect input signal can result in artefacts if there is a difference between the incoming rate and the locl DAC clock. Cheers Thomas

Thomas,

The UltraLock system is actually much more complex then just an ASRC. Check out this post from John Siau, the inventor of UltraLock:

http://www.head-fi.org/forums/showpo...&postcount=407

Thanks,
Elias

 

[music_man]

thanks mr. gwinn.

i will use coaxial s/pdif from now on! i always figure that a real coaxial cable is better than some $500 cable that is not even coaxial.

i have dac's that have no apparent jitter resistance or correction. they sound ok. granted, they do not bring out every detail and nuance like the dac1 does.

are you saying these non jitter correcting dacs sound terrible? i know the dac1 is technically far superior to those designs but can't some of the inexpensive designs sound "ok" too? some sound ok to me.

benchmark is an amazing company that everyone can speak with the engineers. that is awesome. i wish i could ask you if another companies dac actually has jitter correction. since that companies tech support doesnt usually know their own names. of course i know you do not want to comment on other companies products. so i respect that.

thanks,
music_man

 

[A.Thorsen]

Quote:

Originally Posted by music_man /img/forum/go_quote.gif thanks mr. gwinn. i will use coaxial s/pdif from now on! i always figure that a real coaxial cable is better than some $500 cable that is not even coaxial. i have dac's that have no apparent jitter resistance or correction. they sound ok. granted, they do not bring out every detail and nuance like the dac1 does. are you saying these non jitter correcting dacs sound terrible? i know the dac1 is technically far superior to those designs but can't some of the inexpensive designs sound "ok" too? some sound ok to me. benchmark is an amazing company that everyone can speak with the engineers. that is awesome. i wish i could ask you if another companies dac actually has jitter correction. since that companies tech support doesnt usually know their own names. of course i know you do not want to comment on other companies products. so i respect that. thanks, music_man

Even if they're not here on this forum, most of the companies will be more than happy to answer questions over phone and/or email. Give 'em a shot. It can't hurt anything.

 

[EliasGwinn]

Quote:

Originally Posted by music_man /img/forum/go_quote.gif are you saying these non jitter correcting dacs sound terrible? i know the dac1 is technically far superior to those designs but can't some of the inexpensive designs sound "ok" too? some sound ok to me.

Music_man,

No, I'm not saying any devices sound terrible. I usually try to refrain from making subjective statements about competitors products, and I never state subjective qualities as fact. I will say that these devices have significant amounts of audio that is not present in the source CD (or whatever source). Whether or not someone enjoys those added artifacts is none of my business.

My feeling on anything audio is, if you enjoy it, by all means, please continue doing so. On the 'Audio-Wiki' on our website, I posted the instructions for achieving bit-transparent audio. I've had people ask "Do I have to turn off these DSP plug-ins and effects? I like how they sound." My answer is always the same: "Do whatever your heart desires - as long as its legal"

.

Thanks,
Elias

 

[infinitesymphony]

Just curious... How many sources on the market today are capable of AES/EBU digital output? I know that many audio interfaces/cards include it as a selectable output method (ex. E-MU 1212M), but it seems like only high-end CDPs or transports would have that sort of feature.

 

[pageman99]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif Just curious... How many sources on the market today are capable of AES/EBU digital output? I know that many audio interfaces/cards include it as a selectable output method (ex. E-MU 1212M), but it seems like only high-end CDPs or transports would have that sort of feature.

Heck, my Behringer SRC2496 has AES/EBU and it only cost me $100! While not my main DAC, it still sounds amazingly good. And that's in absolute terms, though certainly not in the DAC1 league, for the price it's very difficult to beat.

Naturally, I'm told it's out of production now.